diff options
| author | Karen Arutyunov <karen@codesynthesis.com> | 2019-08-24 17:41:30 +0300 |
|---|---|---|
| committer | Karen Arutyunov <karen@codesynthesis.com> | 2019-08-28 15:01:48 +0300 |
| commit | 4bdf53837e010073de802070d4e6087410662d3e (patch) | |
| tree | 2820d3964877d1a7d498833da325aa3d3a699353 /libbuild2/cc/compile-rule.cxx | |
| parent | ea24f530048cbce0c5335ca3fd3632c8ce34315a (diff) | |
Move cc build system module to separate library
Diffstat (limited to 'libbuild2/cc/compile-rule.cxx')
| -rw-r--r-- | libbuild2/cc/compile-rule.cxx | 6098 |
1 files changed, 6098 insertions, 0 deletions
diff --git a/libbuild2/cc/compile-rule.cxx b/libbuild2/cc/compile-rule.cxx new file mode 100644 index 0000000..8cebef0 --- /dev/null +++ b/libbuild2/cc/compile-rule.cxx @@ -0,0 +1,6098 @@ +// file : libbuild2/cc/compile-rule.cxx -*- C++ -*- +// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd +// license : MIT; see accompanying LICENSE file + +#include <libbuild2/cc/compile-rule.hxx> + +#include <cstdlib> // exit() +#include <cstring> // strlen(), strchr() + +#include <libbuild2/file.hxx> +#include <libbuild2/depdb.hxx> +#include <libbuild2/scope.hxx> +#include <libbuild2/context.hxx> +#include <libbuild2/variable.hxx> +#include <libbuild2/algorithm.hxx> +#include <libbuild2/filesystem.hxx> // mtime() +#include <libbuild2/diagnostics.hxx> + +#include <libbuild2/config/utility.hxx> // create_project() + +#include <libbuild2/bin/target.hxx> + +#include <libbuild2/cc/parser.hxx> +#include <libbuild2/cc/target.hxx> // h +#include <libbuild2/cc/module.hxx> +#include <libbuild2/cc/utility.hxx> + +using std::exit; +using std::strlen; + +using namespace butl; + +namespace build2 +{ + namespace cc + { + using namespace bin; + + // Module type/info string serialization. + // + // The string representation is a space-separated list of module names + // or quoted paths for header units with the following rules: + // + // 1. If this is a module unit, then the first name is the module name + // intself following by either '!' for an interface or header unit and + // by '+' for an implementation unit. + // + // 2. If an imported module is re-exported, then the module name is + // followed by '*'. + // + // For example: + // + // foo! foo.core* foo.base* foo.impl + // foo.base+ foo.impl + // foo.base foo.impl + // "/usr/include/stdio.h"! + // "/usr/include/stdio.h"! "/usr/include/stddef.h" + // + // NOTE: currently we omit the imported header units since we have no need + // for this information (everything is handled by the mapper). Plus, + // resolving an import declaration to an absolute path would require + // some effort. + // + static string + to_string (unit_type ut, const module_info& mi) + { + string s; + + if (ut != unit_type::non_modular) + { + if (ut == unit_type::module_header) s += '"'; + s += mi.name; + if (ut == unit_type::module_header) s += '"'; + + s += (ut == unit_type::module_impl ? '+' : '!'); + } + + for (const module_import& i: mi.imports) + { + if (!s.empty ()) + s += ' '; + + if (i.type == unit_type::module_header) s += '"'; + s += i.name; + if (i.type == unit_type::module_header) s += '"'; + + if (i.exported) + s += '*'; + } + + return s; + } + + static pair<unit_type, module_info> + to_module_info (const string& s) + { + unit_type ut (unit_type::non_modular); + module_info mi; + + for (size_t b (0), e (0), n (s.size ()), m; e < n; ) + { + // Let's handle paths with spaces seeing that we already quote them. + // + char d (s[b = e] == '"' ? '"' : ' '); + + if ((m = next_word (s, n, b, e, d)) == 0) + break; + + char c (d == ' ' ? s[e - 1] : // Before delimiter. + e + 1 < n ? s[e + 1] : // After delimiter. + '\0'); + + switch (c) + { + case '!': + case '+': + case '*': break; + default: c = '\0'; + } + + string w (s, b, m - (d == ' ' && c != '\0' ? 1 : 0)); + + unit_type t (c == '+' ? unit_type::module_impl : + d == ' ' ? unit_type::module_iface : + unit_type::module_header); + + if (c == '!' || c == '+') + { + ut = t; + mi.name = move (w); + } + else + mi.imports.push_back (module_import {t, move (w), c == '*', 0}); + + // Skip to the next word (quote and space or just space). + // + e += (d == '"' ? 2 : 1); + } + + return pair<unit_type, module_info> (move (ut), move (mi)); + } + + // preprocessed + // + template <typename T> + inline bool + operator< (preprocessed l, T r) // Template because of VC14 bug. + { + return static_cast<uint8_t> (l) < static_cast<uint8_t> (r); + } + + preprocessed + to_preprocessed (const string& s) + { + if (s == "none") return preprocessed::none; + if (s == "includes") return preprocessed::includes; + if (s == "modules") return preprocessed::modules; + if (s == "all") return preprocessed::all; + throw invalid_argument ("invalid preprocessed value '" + s + "'"); + } + + struct compile_rule::match_data + { + explicit + match_data (unit_type t, const prerequisite_member& s) + : type (t), src (s) {} + + unit_type type; + preprocessed pp = preprocessed::none; + bool symexport = false; // Target uses __symexport. + bool touch = false; // Target needs to be touched. + timestamp mt = timestamp_unknown; // Target timestamp. + prerequisite_member src; + auto_rmfile psrc; // Preprocessed source, if any. + path dd; // Dependency database path. + size_t headers = 0; // Number of imported header units. + module_positions modules = {0, 0, 0}; // Positions of imported modules. + }; + + compile_rule:: + compile_rule (data&& d) + : common (move (d)), + rule_id (string (x) += ".compile 4") + { + static_assert (sizeof (match_data) <= target::data_size, + "insufficient space"); + } + + size_t compile_rule:: + append_lang_options (cstrings& args, const match_data& md) const + { + size_t r (args.size ()); + + // Normally there will be one or two options/arguments. + // + const char* o1 (nullptr); + const char* o2 (nullptr); + + switch (cclass) + { + case compiler_class::msvc: + { + switch (x_lang) + { + case lang::c: o1 = "/TC"; break; + case lang::cxx: o1 = "/TP"; break; + } + break; + } + case compiler_class::gcc: + { + // For GCC we ignore the preprocessed value since it is handled via + // -fpreprocessed -fdirectives-only. + // + // Clang has *-cpp-output (but not c++-module-cpp-output) and they + // handle comments and line continuations. However, currently this + // is only by accident since these modes are essentially equivalent + // to their cpp-output-less versions. + // + switch (md.type) + { + case unit_type::non_modular: + case unit_type::module_impl: + { + o1 = "-x"; + switch (x_lang) + { + case lang::c: o2 = "c"; break; + case lang::cxx: o2 = "c++"; break; + } + break; + } + case unit_type::module_iface: + case unit_type::module_header: + { + // Here things get rather compiler-specific. We also assume + // the language is C++. + // + bool h (md.type == unit_type::module_header); + + //@@ MODHDR TODO: should we try to distinguish c-header vs + // c++-header based on the source target type? + + switch (ctype) + { + case compiler_type::gcc: + { + // In GCC compiling a header unit required -fmodule-header + // in addition to -x c/c++-header. Probably because relying + // on just -x would be ambigous with its PCH support. + // + if (h) + args.push_back ("-fmodule-header"); + + o1 = "-x"; + o2 = h ? "c++-header" : "c++"; + break; + } + case compiler_type::clang: + { + o1 = "-x"; + o2 = h ? "c++-header" : "c++-module"; + break; + } + default: + assert (false); + } + break; + } + } + break; + } + } + + if (o1 != nullptr) args.push_back (o1); + if (o2 != nullptr) args.push_back (o2); + + return args.size () - r; + } + + inline void compile_rule:: + append_symexport_options (cstrings& args, const target& t) const + { + // With VC if a BMI is compiled with dllexport, then when such BMI is + // imported, it is auto-magically treated as dllimport. Let's hope + // other compilers follow suit. + // + args.push_back (t.is_a<bmis> () && tclass == "windows" + ? "-D__symexport=__declspec(dllexport)" + : "-D__symexport="); + } + + bool compile_rule:: + match (action a, target& t, const string&) const + { + tracer trace (x, "compile_rule::match"); + + // Note: unit type will be refined in apply(). + // + unit_type ut (t.is_a<hbmix> () ? unit_type::module_header : + t.is_a<bmix> () ? unit_type::module_iface : + unit_type::non_modular); + + // Link-up to our group (this is the obj/bmi{} target group protocol + // which means this can be done whether we match or not). + // + if (t.group == nullptr) + t.group = &search (t, + (ut == unit_type::module_header ? hbmi::static_type: + ut == unit_type::module_iface ? bmi::static_type : + obj::static_type), + t.dir, t.out, t.name); + + // See if we have a source file. Iterate in reverse so that a source + // file specified for a member overrides the one specified for the + // group. Also "see through" groups. + // + for (prerequisite_member p: reverse_group_prerequisite_members (a, t)) + { + // If excluded or ad hoc, then don't factor it into our tests. + // + if (include (a, t, p) != include_type::normal) + continue; + + // For a header unit we check the "real header" plus the C header. + // + if (ut == unit_type::module_header ? p.is_a (**x_hdr) || p.is_a<h> () : + ut == unit_type::module_iface ? p.is_a (*x_mod) : + p.is_a (x_src)) + { + // Save in the target's auxiliary storage. + // + t.data (match_data (ut, p)); + return true; + } + } + + l4 ([&]{trace << "no " << x_lang << " source file for target " << t;}); + return false; + } + + // Append or hash library options from a pair of *.export.* variables + // (first one is cc.export.*) recursively, prerequisite libraries first. + // + void compile_rule:: + append_lib_options (const scope& bs, + cstrings& args, + action a, + const target& t, + linfo li) const + { + // See through utility libraries. + // + auto imp = [] (const file& l, bool la) {return la && l.is_a<libux> ();}; + + auto opt = [&args, this] ( + const file& l, const string& t, bool com, bool exp) + { + // Note that in our model *.export.poptions are always "interface", + // even if set on liba{}/libs{}, unlike loptions. + // + if (!exp) // Ignore libux. + return; + + const variable& var ( + com + ? c_export_poptions + : (t == x + ? x_export_poptions + : l.ctx.var_pool[t + ".export.poptions"])); + + append_options (args, l, var); + }; + + // In case we don't have the "small function object" optimization. + // + const function<bool (const file&, bool)> impf (imp); + const function<void (const file&, const string&, bool, bool)> optf (opt); + + for (prerequisite_member p: group_prerequisite_members (a, t)) + { + if (include (a, t, p) != include_type::normal) // Excluded/ad hoc. + continue; + + // Should be already searched and matched for libraries. + // + if (const target* pt = p.load ()) + { + if (const libx* l = pt->is_a<libx> ()) + pt = link_member (*l, a, li); + + bool la; + if (!((la = pt->is_a<liba> ()) || + (la = pt->is_a<libux> ()) || + pt->is_a<libs> ())) + continue; + + process_libraries (a, bs, li, sys_lib_dirs, + pt->as<file> (), la, 0, // Hack: lflags unused. + impf, nullptr, optf); + } + } + } + + void compile_rule:: + hash_lib_options (const scope& bs, + sha256& cs, + action a, + const target& t, + linfo li) const + { + auto imp = [] (const file& l, bool la) {return la && l.is_a<libux> ();}; + + auto opt = [&cs, this] ( + const file& l, const string& t, bool com, bool exp) + { + if (!exp) + return; + + const variable& var ( + com + ? c_export_poptions + : (t == x + ? x_export_poptions + : l.ctx.var_pool[t + ".export.poptions"])); + + hash_options (cs, l, var); + }; + + // The same logic as in append_lib_options(). + // + const function<bool (const file&, bool)> impf (imp); + const function<void (const file&, const string&, bool, bool)> optf (opt); + + for (prerequisite_member p: group_prerequisite_members (a, t)) + { + if (include (a, t, p) != include_type::normal) // Excluded/ad hoc. + continue; + + if (const target* pt = p.load ()) + { + if (const libx* l = pt->is_a<libx> ()) + pt = link_member (*l, a, li); + + bool la; + if (!((la = pt->is_a<liba> ()) || + (la = pt->is_a<libux> ()) || + pt->is_a<libs> ())) + continue; + + process_libraries (a, bs, li, sys_lib_dirs, + pt->as<file> (), la, 0, // Hack: lflags unused. + impf, nullptr, optf); + } + } + } + + // Append library prefixes based on the *.export.poptions variables + // recursively, prerequisite libraries first. + // + void compile_rule:: + append_lib_prefixes (const scope& bs, + prefix_map& m, + action a, + target& t, + linfo li) const + { + auto imp = [] (const file& l, bool la) {return la && l.is_a<libux> ();}; + + auto opt = [&m, this] ( + const file& l, const string& t, bool com, bool exp) + { + if (!exp) + return; + + const variable& var ( + com + ? c_export_poptions + : (t == x + ? x_export_poptions + : l.ctx.var_pool[t + ".export.poptions"])); + + append_prefixes (m, l, var); + }; + + // The same logic as in append_lib_options(). + // + const function<bool (const file&, bool)> impf (imp); + const function<void (const file&, const string&, bool, bool)> optf (opt); + + for (prerequisite_member p: group_prerequisite_members (a, t)) + { + if (include (a, t, p) != include_type::normal) // Excluded/ad hoc. + continue; + + if (const target* pt = p.load ()) + { + if (const libx* l = pt->is_a<libx> ()) + pt = link_member (*l, a, li); + + bool la; + if (!((la = pt->is_a<liba> ()) || + (la = pt->is_a<libux> ()) || + pt->is_a<libs> ())) + continue; + + process_libraries (a, bs, li, sys_lib_dirs, + pt->as<file> (), la, 0, // Hack: lflags unused. + impf, nullptr, optf); + } + } + } + + // Update the target during the match phase. Return true if it has changed + // or if the passed timestamp is not timestamp_unknown and is older than + // the target. + // + // This function is used to make sure header dependencies are up to date. + // + // There would normally be a lot of headers for every source file (think + // all the system headers) and just calling execute_direct() on all of + // them can get expensive. At the same time, most of these headers are + // existing files that we will never be updating (again, system headers, + // for example) and the rule that will match them is the fallback + // file_rule. That rule has an optimization: it returns noop_recipe (which + // causes the target state to be automatically set to unchanged) if the + // file is known to be up to date. So we do the update "smartly". + // + static bool + update (tracer& trace, action a, const target& t, timestamp ts) + { + const path_target* pt (t.is_a<path_target> ()); + + if (pt == nullptr) + ts = timestamp_unknown; + + target_state os (t.matched_state (a)); + + if (os == target_state::unchanged) + { + if (ts == timestamp_unknown) + return false; + else + { + // We expect the timestamp to be known (i.e., existing file). + // + timestamp mt (pt->mtime ()); + assert (mt != timestamp_unknown); + return mt > ts; + } + } + else + { + // We only want to return true if our call to execute() actually + // caused an update. In particular, the target could already have been + // in target_state::changed because of a dependency extraction run for + // some other source file. + // + // @@ MT perf: so we are going to switch the phase and execute for + // any generated header. + // + phase_switch ps (t.ctx, run_phase::execute); + target_state ns (execute_direct (a, t)); + + if (ns != os && ns != target_state::unchanged) + { + l6 ([&]{trace << "updated " << t + << "; old state " << os + << "; new state " << ns;}); + return true; + } + else + return ts != timestamp_unknown ? pt->newer (ts) : false; + } + } + + recipe compile_rule:: + apply (action a, target& xt) const + { + tracer trace (x, "compile_rule::apply"); + + file& t (xt.as<file> ()); // Either obj*{} or bmi*{}. + + match_data& md (t.data<match_data> ()); + + context& ctx (t.ctx); + + // Note: until refined below, non-BMI-generating translation unit is + // assumed non-modular. + // + unit_type ut (md.type); + + const scope& bs (t.base_scope ()); + const scope& rs (*bs.root_scope ()); + + otype ot (compile_type (t, ut)); + linfo li (link_info (bs, ot)); // Link info for selecting libraries. + compile_target_types tts (compile_types (ot)); + + // Derive file name from target name. + // + string e; // Primary target extension (module or object). + { + const char* o ("o"); // Object extension (.o or .obj). + + if (tsys == "win32-msvc") + { + switch (ot) + { + case otype::e: e = "exe."; break; + case otype::a: e = "lib."; break; + case otype::s: e = "dll."; break; + } + o = "obj"; + } + else if (tsys == "mingw32") + { + switch (ot) + { + case otype::e: e = "exe."; break; + case otype::a: e = "a."; break; + case otype::s: e = "dll."; break; + } + } + else if (tsys == "darwin") + { + switch (ot) + { + case otype::e: e = ""; break; + case otype::a: e = "a."; break; + case otype::s: e = "dylib."; break; + } + } + else + { + switch (ot) + { + case otype::e: e = ""; break; + case otype::a: e = "a."; break; + case otype::s: e = "so."; break; + } + } + + switch (ctype) + { + case compiler_type::gcc: + { + e += (ut != unit_type::non_modular ? "gcm" : o); + break; + } + case compiler_type::clang: + { + e += (ut != unit_type::non_modular ? "pcm" : o); + break; + } + case compiler_type::msvc: + { + e += (ut != unit_type::non_modular ? "ifc" : o); + break; + } + case compiler_type::icc: + { + assert (ut == unit_type::non_modular); + e += o; + } + } + + // If we are compiling a module, then the obj*{} is an ad hoc member + // of bmi*{}. For now neither GCC nor Clang produce an object file + // for a header unit (but something tells me this is going to change). + // + if (ut == unit_type::module_iface) + { + // The module interface unit can be the same as an implementation + // (e.g., foo.mxx and foo.cxx) which means obj*{} targets could + // collide. So we add the module extension to the target name. + // + file& obj (add_adhoc_member<file> (t, tts.obj, e.c_str ())); + + if (obj.path ().empty ()) + obj.derive_path (o); + } + } + + const path& tp (t.derive_path (e.c_str ())); + + // Inject dependency on the output directory. + // + const fsdir* dir (inject_fsdir (a, t)); + + // Match all the existing prerequisites. The injection code takes care + // of the ones it is adding. + // + // When cleaning, ignore prerequisites that are not in the same or a + // subdirectory of our project root. + // + auto& pts (t.prerequisite_targets[a]); + optional<dir_paths> usr_lib_dirs; // Extract lazily. + + // Start asynchronous matching of prerequisites. Wait with unlocked + // phase to allow phase switching. + // + wait_guard wg (ctx, ctx.count_busy (), t[a].task_count, true); + + size_t start (pts.size ()); // Index of the first to be added. + for (prerequisite_member p: group_prerequisite_members (a, t)) + { + const target* pt (nullptr); + include_type pi (include (a, t, p)); + + if (!pi) + continue; + + // A dependency on a library is there so that we can get its + // *.export.poptions, modules, etc. This is the library + // meta-information protocol. See also append_lib_options(). + // + if (pi == include_type::normal && + (p.is_a<libx> () || + p.is_a<liba> () || + p.is_a<libs> () || + p.is_a<libux> ())) + { + if (a.operation () == update_id) + { + // Handle (phase two) imported libraries. We know that for such + // libraries we don't need to do match() in order to get options + // (if any, they would be set by search_library()). + // + if (p.proj ()) + { + if (search_library (a, + sys_lib_dirs, + usr_lib_dirs, + p.prerequisite) != nullptr) + continue; + } + + pt = &p.search (t); + + if (const libx* l = pt->is_a<libx> ()) + pt = link_member (*l, a, li); + } + else + continue; + } + // + // For modules we pick only what we import which is done below so + // skip it here. One corner case is clean: we assume that someone + // else (normally library/executable) also depends on it and will + // clean it up. + // + else if (pi == include_type::normal && + (p.is_a<bmi> () || p.is_a (tts.bmi) || + p.is_a<hbmi> () || p.is_a (tts.hbmi))) + continue; + else + { + pt = &p.search (t); + + if (a.operation () == clean_id && !pt->dir.sub (rs.out_path ())) + continue; + } + + match_async (a, *pt, ctx.count_busy (), t[a].task_count); + pts.push_back (prerequisite_target (pt, pi)); + } + + wg.wait (); + + // Finish matching all the targets that we have started. + // + for (size_t i (start), n (pts.size ()); i != n; ++i) + { + const target*& pt (pts[i]); + + // Making sure a library is updated before us will only restrict + // parallelism. But we do need to match it in order to get its imports + // resolved and prerequisite_targets populated. So we match it but + // then unmatch if it is safe. And thanks to the two-pass prerequisite + // match in link::apply() it will be safe unless someone is building + // an obj?{} target directory. + // + if (build2::match ( + a, + *pt, + pt->is_a<liba> () || pt->is_a<libs> () || pt->is_a<libux> () + ? unmatch::safe + : unmatch::none)) + pt = nullptr; // Ignore in execute. + } + + // Inject additional prerequisites. We only do it when performing update + // since chances are we will have to update some of our prerequisites in + // the process (auto-generated source code, header units). + // + if (a == perform_update_id) + { + // The cached prerequisite target should be the same as what is in + // t.prerequisite_targets since we used standard search() and match() + // above. + // + const file& src (*md.src.search (t).is_a<file> ()); + + // Figure out if __symexport is used. While normally it is specified + // on the project root (which we cached), it can be overridden with + // a target-specific value for installed modules (which we sidebuild + // as part of our project). + // + // @@ MODHDR MSVC: are we going to do the same for header units? I + // guess we will figure it out when MSVC supports header units. + // Also see hashing below. + // + if (ut == unit_type::module_iface) + { + lookup l (src.vars[x_symexport]); + md.symexport = l ? cast<bool> (l) : symexport; + } + + // Make sure the output directory exists. + // + // Is this the right thing to do? It does smell a bit, but then we do + // worse things in inject_prerequisites() below. There is also no way + // to postpone this until update since we need to extract and inject + // header dependencies now (we don't want to be calling search() and + // match() in update), which means we need to cache them now as well. + // So the only alternative, it seems, is to cache the updates to the + // database until later which will sure complicate (and slow down) + // things. + // + if (dir != nullptr) + { + // We can do it properly by using execute_direct(). But this means + // we will be switching to the execute phase with all the associated + // overheads. At the same time, in case of update, creation of a + // directory is not going to change the external state in any way + // that would affect any parallel efforts in building the internal + // state. So we are just going to create the directory directly. + // Note, however, that we cannot modify the fsdir{} target since + // this can very well be happening in parallel. But that's not a + // problem since fsdir{}'s update is idempotent. + // + fsdir_rule::perform_update_direct (a, t); + } + + // Note: the leading '@' is reserved for the module map prefix (see + // extract_modules()) and no other line must start with it. + // + depdb dd (tp + ".d"); + + // First should come the rule name/version. + // + if (dd.expect (rule_id) != nullptr) + l4 ([&]{trace << "rule mismatch forcing update of " << t;}); + + // Then the compiler checksum. Note that here we assume it + // incorporates the (default) target so that if the compiler changes + // but only in what it targets, then the checksum will still change. + // + if (dd.expect (cast<string> (rs[x_checksum])) != nullptr) + l4 ([&]{trace << "compiler mismatch forcing update of " << t;}); + + // Then the options checksum. + // + // The idea is to keep them exactly as they are passed to the compiler + // since the order may be significant. + // + { + sha256 cs; + + // These flags affect how we compile the source and/or the format of + // depdb so factor them in. + // + cs.append (&md.pp, sizeof (md.pp)); + + if (ut == unit_type::module_iface) + cs.append (&md.symexport, sizeof (md.symexport)); + + if (import_hdr != nullptr) + hash_options (cs, *import_hdr); + + if (md.pp != preprocessed::all) + { + hash_options (cs, t, c_poptions); + hash_options (cs, t, x_poptions); + + // Hash *.export.poptions from prerequisite libraries. + // + hash_lib_options (bs, cs, a, t, li); + + // Extra system header dirs (last). + // + assert (sys_inc_dirs_extra <= sys_inc_dirs.size ()); + hash_option_values ( + cs, "-I", + sys_inc_dirs.begin () + sys_inc_dirs_extra, sys_inc_dirs.end (), + [] (const dir_path& d) {return d.string ();}); + } + + hash_options (cs, t, c_coptions); + hash_options (cs, t, x_coptions); + hash_options (cs, tstd); + + if (ot == otype::s) + { + // On Darwin, Win32 -fPIC is the default. + // + if (tclass == "linux" || tclass == "bsd") + cs.append ("-fPIC"); + } + + if (dd.expect (cs.string ()) != nullptr) + l4 ([&]{trace << "options mismatch forcing update of " << t;}); + } + + // Finally the source file. + // + if (dd.expect (src.path ()) != nullptr) + l4 ([&]{trace << "source file mismatch forcing update of " << t;}); + + // If any of the above checks resulted in a mismatch (different + // compiler, options, or source file) or if the depdb is newer than + // the target (interrupted update), then do unconditional update. + // + // Note that load_mtime() can only be used in the execute phase so we + // have to check for a cached value manually. + // + bool u; + timestamp mt; + + if (dd.writing ()) + u = true; + else + { + if ((mt = t.mtime ()) == timestamp_unknown) + t.mtime (mt = mtime (tp)); // Cache. + + u = dd.mtime > mt; + } + + if (u) + mt = timestamp_nonexistent; // Treat as if it doesn't exist. + + // Update prerequisite targets (normally just the source file). + // + // This is an unusual place and time to do it. But we have to do it + // before extracting dependencies. The reasoning for source file is + // pretty clear. What other prerequisites could we have? While + // normally they will be some other sources (as in, static content + // from src_root), it's possible they are some auto-generated stuff. + // And it's possible they affect the preprocessor result. Say some ad + // hoc/out-of-band compiler input file that is passed via the command + // line. So, to be safe, we make sure everything is up to date. + // + for (const target* pt: pts) + { + if (pt == nullptr || pt == dir) + continue; + + u = update (trace, a, *pt, u ? timestamp_unknown : mt) || u; + } + + // Check if the source is already preprocessed to a certain degree. + // This determines which of the following steps we perform and on + // what source (original or preprocessed). + // + // Note: must be set on the src target. + // + if (const string* v = cast_null<string> (src[x_preprocessed])) + try + { + md.pp = to_preprocessed (*v); + } + catch (const invalid_argument& e) + { + fail << "invalid " << x_preprocessed.name << " variable value " + << "for target " << src << ": " << e; + } + + // If we have no #include directives (or header unit imports), then + // skip header dependency extraction. + // + pair<auto_rmfile, bool> psrc (auto_rmfile (), false); + if (md.pp < preprocessed::includes) + { + // Note: trace is used in a test. + // + l5 ([&]{trace << "extracting headers from " << src;}); + psrc = extract_headers (a, bs, t, li, src, md, dd, u, mt); + } + + // Next we "obtain" the translation unit information. What exactly + // "obtain" entails is tricky: If things changed, then we re-parse the + // translation unit. Otherwise, we re-create this information from + // depdb. We, however, have to do it here and now in case the database + // is invalid and we still have to fallback to re-parse. + // + // Store the translation unit's checksum to detect ignorable changes + // (whitespaces, comments, etc). + // + { + optional<string> cs; + if (string* l = dd.read ()) + cs = move (*l); + else + u = true; // Database is invalid, force re-parse. + + unit tu; + for (bool first (true);; first = false) + { + if (u) + { + // Flush depdb since it can be used (as a module map) by + // parse_unit(). + // + if (dd.writing ()) + dd.flush (); + + auto p (parse_unit (a, t, li, src, psrc.first, md, dd.path)); + + if (!cs || *cs != p.second) + { + assert (first); // Unchanged TU has a different checksum? + dd.write (p.second); + } + // + // Don't clear if it was forced or the checksum should not be + // relied upon. + // + else if (first && !p.second.empty ()) + { + // Clear the update flag and set the touch flag. Unless there + // is no object file, of course. See also the md.mt logic + // below. + // + if (mt != timestamp_nonexistent) + { + u = false; + md.touch = true; + } + } + + tu = move (p.first); + } + + if (modules) + { + if (u || !first) + { + string s (to_string (tu.type, tu.module_info)); + + if (first) + dd.expect (s); + else + dd.write (s); + } + else + { + if (string* l = dd.read ()) + { + auto p (to_module_info (*l)); + tu.type = p.first; + tu.module_info = move (p.second); + } + else + { + u = true; // Database is invalid, force re-parse. + continue; + } + } + } + + break; + } + + // Make sure the translation unit type matches the resulting target + // type. + // + switch (tu.type) + { + case unit_type::non_modular: + case unit_type::module_impl: + { + if (ut != unit_type::non_modular) + fail << "translation unit " << src << " is not a module interface" << + info << "consider using " << x_src.name << "{} instead"; + break; + } + case unit_type::module_iface: + { + if (ut != unit_type::module_iface) + fail << "translation unit " << src << " is a module interface" << + info << "consider using " << x_mod->name << "{} instead"; + break; + } + case unit_type::module_header: + { + assert (ut == unit_type::module_header); + break; + } + } + + // Refine the non-modular/module-impl decision from match(). + // + ut = md.type = tu.type; + + // Note: trace is used in a test. + // + l5 ([&]{trace << "extracting modules from " << t;}); + + // Extract the module dependency information in addition to header + // dependencies. + // + // NOTE: assumes that no further targets will be added into + // t.prerequisite_targets! + // + if (modules) + { + extract_modules (a, bs, t, li, + tts, src, + md, move (tu.module_info), dd, u); + + // Currently in VC module interface units must be compiled from + // the original source (something to do with having to detect and + // store header boundaries in the .ifc files). + // + // @@ MODHDR MSVC: should we do the same for header units? I guess + // we will figure it out when MSVC supports header units. + // + if (ctype == compiler_type::msvc) + { + if (ut == unit_type::module_iface) + psrc.second = false; + } + } + } + + // If anything got updated, then we didn't rely on the cache. However, + // the cached data could actually have been valid and the compiler run + // in extract_headers() as well as the code above merely validated it. + // + // We do need to update the database timestamp, however. Failed that, + // we will keep re-validating the cached data over and over again. + // + // @@ DRYRUN: note that for dry-run we would keep re-touching the + // database on every run (because u is true). So for now we suppress + // it (the file will be re-validated on the real run anyway). It feels + // like support for reusing the (partially) preprocessed output (see + // note below) should help solve this properly (i.e., we don't want + // to keep re-validating the file on every subsequent dry-run as well + // on the real run). + // + if (u && dd.reading () && !ctx.dry_run) + dd.touch = true; + + dd.close (); + md.dd = move (dd.path); + + // If the preprocessed output is suitable for compilation, then pass + // it along. + // + if (psrc.second) + { + md.psrc = move (psrc.first); + + // Without modules keeping the (partially) preprocessed output + // around doesn't buy us much: if the source/headers haven't changed + // then neither will the object file. Modules make things more + // interesting: now we may have to recompile an otherwise unchanged + // translation unit because a BMI it depends on has changed. In this + // case re-processing the translation unit would be a waste and + // compiling the original source would break distributed + // compilation. + // + // Note also that the long term trend will (hopefully) be for + // modularized projects to get rid of #include's which means the + // need for producing this partially preprocessed output will + // (hopefully) gradually disappear. + // + if (modules) + md.psrc.active = false; // Keep. + } + + // Above we may have ignored changes to the translation unit. The + // problem is, unless we also update the target's timestamp, we will + // keep re-checking this on subsequent runs and it is not cheap. + // Updating the target's timestamp is not without problems either: it + // will cause a re-link on a subsequent run. So, essentially, we + // somehow need to remember two timestamps: one for checking + // "preprocessor prerequisites" above and one for checking other + // prerequisites (like modules) below. So what we are going to do is + // store the first in the target file (so we do touch it) and the + // second in depdb (which is never newer that the target). + // + // Perhaps when we start keeping the partially preprocessed this will + // fall away? Yes, please. + // + md.mt = u ? timestamp_nonexistent : dd.mtime; + } + + switch (a) + { + case perform_update_id: return [this] (action a, const target& t) + { + return perform_update (a, t); + }; + case perform_clean_id: return [this] (action a, const target& t) + { + return perform_clean (a, t); + }; + default: return noop_recipe; // Configure update. + } + } + + // Reverse-lookup target type(s) from extension. + // + small_vector<const target_type*, 2> compile_rule:: + map_extension (const scope& s, const string& n, const string& e) const + { + // We will just have to try all of the possible ones, in the "most + // likely to match" order. + // + auto test = [&s, &n, &e] (const target_type& tt) -> bool + { + // Call the extension derivation function. Here we know that it will + // only use the target type and name from the target key so we can + // pass bogus values for the rest. + // + target_key tk {&tt, nullptr, nullptr, &n, nullopt}; + + // This is like prerequisite search. + // + optional<string> de (tt.default_extension (tk, s, nullptr, true)); + + return de && *de == e; + }; + + small_vector<const target_type*, 2> r; + + for (const target_type* const* p (x_inc); *p != nullptr; ++p) + if (test (**p)) + r.push_back (*p); + + return r; + } + + void compile_rule:: + append_prefixes (prefix_map& m, const target& t, const variable& var) const + { + tracer trace (x, "compile_rule::append_prefixes"); + + // If this target does not belong to any project (e.g, an "imported as + // installed" library), then it can't possibly generate any headers for + // us. + // + const scope& bs (t.base_scope ()); + const scope* rs (bs.root_scope ()); + if (rs == nullptr) + return; + + const dir_path& out_base (t.dir); + const dir_path& out_root (rs->out_path ()); + + if (auto l = t[var]) + { + const auto& v (cast<strings> (l)); + + for (auto i (v.begin ()), e (v.end ()); i != e; ++i) + { + // -I can either be in the "-Ifoo" or "-I foo" form. For VC it can + // also be /I. + // + const string& o (*i); + + if (o.size () < 2 || (o[0] != '-' && o[0] != '/') || o[1] != 'I') + continue; + + dir_path d; + + try + { + if (o.size () == 2) + { + if (++i == e) + break; // Let the compiler complain. + + d = dir_path (*i); + } + else + d = dir_path (*i, 2, string::npos); + } + catch (const invalid_path& e) + { + fail << "invalid directory '" << e.path << "'" + << " in option '" << o << "'" + << " in variable " << var + << " for target " << t; + } + + l6 ([&]{trace << "-I " << d;}); + + if (d.relative ()) + fail << "relative directory " << d + << " in option '" << o << "'" + << " in variable " << var + << " for target " << t; + + // If the directory is not normalized, we can complain or normalize + // it. Let's go with normalizing to minimize questions/complaints. + // + if (!d.normalized (false)) // Allow non-canonical dir separators. + d.normalize (); + + // If we are not inside our project root, then ignore. + // + if (!d.sub (out_root)) + continue; + + // If the target directory is a sub-directory of the include + // directory, then the prefix is the difference between the + // two. Otherwise, leave it empty. + // + // The idea here is to make this "canonical" setup work auto- + // magically: + // + // 1. We include all files with a prefix, e.g., <foo/bar>. + // 2. The library target is in the foo/ sub-directory, e.g., + // /tmp/foo/. + // 3. The poptions variable contains -I/tmp. + // + dir_path p (out_base.sub (d) ? out_base.leaf (d) : dir_path ()); + + // We use the target's directory as out_base but that doesn't work + // well for targets that are stashed in subdirectories. So as a + // heuristics we are going to also enter the outer directories of + // the original prefix. It is, however, possible, that another -I + // option after this one will produce one of these outer prefixes as + // its original prefix in which case we should override it. + // + // So we are going to assign the original prefix priority value 0 + // (highest) and then increment it for each outer prefix. + // + auto enter = [&trace, &m] (dir_path p, dir_path d, size_t prio) + { + auto j (m.find (p)); + + if (j != m.end ()) + { + prefix_value& v (j->second); + + // We used to reject duplicates but it seems this can be + // reasonably expected to work according to the order of the + // -I options. + // + // Seeing that we normally have more "specific" -I paths first, + // (so that we don't pick up installed headers, etc), we ignore + // it. + // + if (v.directory == d) + { + if (v.priority > prio) + v.priority = prio; + } + else if (v.priority <= prio) + { + if (verb >= 4) + trace << "ignoring mapping for prefix '" << p << "'\n" + << " existing mapping to " << v.directory + << " priority " << v.priority << '\n' + << " another mapping to " << d + << " priority " << prio; + } + else + { + if (verb >= 4) + trace << "overriding mapping for prefix '" << p << "'\n" + << " existing mapping to " << v.directory + << " priority " << v.priority << '\n' + << " new mapping to " << d + << " priority " << prio; + + v.directory = move (d); + v.priority = prio; + } + } + else + { + l6 ([&]{trace << "'" << p << "' -> " << d << " priority " + << prio;}); + m.emplace (move (p), prefix_value {move (d), prio}); + } + }; + +#if 1 + // Enter all outer prefixes, including prefixless. + // + // The prefixless part is fuzzy but seems to be doing the right + // thing ignoring/overriding-wise, at least in cases where one of + // the competing -I paths is a subdirectory of another. But the + // proper solution will be to keep all the prefixless entries (by + // changing prefix_map to a multimap) since for them we have an + // extra check (target must be explicitly spelled out in a + // buildfile). + // + for (size_t prio (0);; ++prio) + { + bool e (p.empty ()); + enter ((e ? move (p) : p), (e ? move (d) : d), prio); + if (e) + break; + p = p.directory (); + } +#else + size_t prio (0); + for (bool e (false); !e; ++prio) + { + dir_path n (p.directory ()); + e = n.empty (); + enter ((e ? move (p) : p), (e ? move (d) : d), prio); + p = move (n); + } +#endif + } + } + } + + auto compile_rule:: + build_prefix_map (const scope& bs, + action a, + target& t, + linfo li) const -> prefix_map + { + prefix_map m; + + // First process our own. + // + append_prefixes (m, t, c_poptions); + append_prefixes (m, t, x_poptions); + + // Then process the include directories from prerequisite libraries. + // + append_lib_prefixes (bs, m, a, t, li); + + return m; + } + + // Return the next make prerequisite starting from the specified + // position and update position to point to the start of the + // following prerequisite or l.size() if there are none left. + // + static string + next_make (const string& l, size_t& p) + { + size_t n (l.size ()); + + // Skip leading spaces. + // + for (; p != n && l[p] == ' '; p++) ; + + // Lines containing multiple prerequisites are 80 characters max. + // + string r; + r.reserve (n); + + // Scan the next prerequisite while watching out for escape sequences. + // + for (; p != n && l[p] != ' '; p++) + { + char c (l[p]); + + if (p + 1 != n) + { + if (c == '$') + { + // Got to be another (escaped) '$'. + // + if (l[p + 1] == '$') + ++p; + } + else if (c == '\\') + { + // This may or may not be an escape sequence depending on whether + // what follows is "escapable". + // + switch (c = l[++p]) + { + case '\\': break; + case ' ': break; + default: c = '\\'; --p; // Restore. + } + } + } + + r += c; + } + + // Skip trailing spaces. + // + for (; p != n && l[p] == ' '; p++) ; + + // Skip final '\'. + // + if (p == n - 1 && l[p] == '\\') + p++; + + return r; + } + + // VC /showIncludes output. The first line is the file being compiled + // (handled by our caller). Then we have the list of headers, one per + // line, in this form (text can presumably be translated): + // + // Note: including file: C:\Program Files (x86)\[...]\iostream + // + // Finally, if we hit a non-existent header, then we end with an error + // line in this form: + // + // x.cpp(3): fatal error C1083: Cannot open include file: 'd/h.hpp': + // No such file or directory + // + // Distinguishing between the include note and the include error is + // easy: we can just check for C1083. Distinguising between the note and + // other errors/warnings is harder: an error could very well end with + // what looks like a path so we cannot look for the note but rather have + // to look for an error. Here we assume that a line containing ' CNNNN:' + // is an error. Should be robust enough in the face of language + // translation, etc. + // + // It turns out C1083 is also used when we are unable to open the main + // source file and the error line (which is printed after the first line + // containing the file name) looks like this: + // + // c1xx: fatal error C1083: Cannot open source file: 's.cpp': No such + // file or directory + + size_t + msvc_sense_diag (const string&, char); // msvc.cxx + + // Extract the include path from the VC /showIncludes output line. Return + // empty string if the line is not an include note or include error. Set + // the good_error flag if it is an include error (which means the process + // will terminate with the error status that needs to be ignored). + // + static string + next_show (const string& l, bool& good_error) + { + // The include error should be the last line that we handle. + // + assert (!good_error); + + size_t p (msvc_sense_diag (l, 'C')); + if (p == string::npos) + { + // Include note. + // + // We assume the path is always at the end but need to handle both + // absolute Windows and POSIX ones. + // + // Note that VC appears to always write the absolute path to the + // included file even if it is ""-included and the source path is + // relative. Aren't we lucky today? + // + p = l.rfind (':'); + + if (p != string::npos) + { + // See if this one is part of the Windows drive letter. + // + if (p > 1 && p + 1 < l.size () && // 2 chars before, 1 after. + l[p - 2] == ' ' && + alpha (l[p - 1]) && + path::traits_type::is_separator (l[p + 1])) + p = l.rfind (':', p - 2); + } + + if (p != string::npos) + { + // VC uses indentation to indicate the include nesting so there + // could be any number of spaces after ':'. Skip them. + // + p = l.find_first_not_of (' ', p + 1); + } + + if (p == string::npos) + fail << "unable to parse /showIncludes include note line \"" + << l << '"'; + + return string (l, p); + } + else if (l.compare (p, 4, "1083") == 0 && + l.compare (0, 5, "c1xx:") != 0 /* Not the main source file. */ ) + { + // Include error. + // + // The path is conveniently quoted with ''. Or so we thought: turns + // out different translations (e.g., Chinese) can use different quote + // characters. But the overall structure seems to be stable: + // + // ...C1083: <translated>: 'd/h.hpp': <translated> + // + // Plus, it seems the quote character could to be multi-byte. + // + size_t p1 (l.find (':', p + 5)); + size_t p2 (l.rfind (':')); + + if (p1 != string::npos && + p2 != string::npos && + (p2 - p1) > 4 && // At least ": 'x':". + l[p1 + 1] == ' ' && + l[p2 + 1] == ' ') + { + p1 += 3; // First character of the path. + p2 -= 1; // One past last character of the path. + + // Skip any non-printable ASCII characters before/after (the mutli- + // byte quote case). + // + auto printable = [] (char c) { return c >= 0x20 && c <= 0x7e; }; + + for (; p1 != p2 && !printable (l[p1]); ++p1) ; + for (; p2 != p1 && !printable (l[p2 - 1]); --p2) ; + + if (p1 != p2) + { + good_error = true; + return string (l, p1 , p2 - p1); + } + } + + fail << "unable to parse /showIncludes include error line \"" + << l << '"' << endf; + } + else + { + // Some other error. + // + return string (); + } + } + + void + msvc_sanitize_cl (cstrings&); // msvc.cxx + + // GCC module mapper handler. + // + // Note that the input stream is non-blocking while output is blocking + // and this function should be prepared to handle closed input stream. + // Any unhandled io_error is handled by the caller as a generic module + // mapper io error. + // + struct compile_rule::module_mapper_state + { + size_t headers = 0; // Number of header units imported. + size_t skip; // Number of depdb entries to skip. + string data; // Auxiliary data. + + explicit + module_mapper_state (size_t skip_count): skip (skip_count) {} + }; + + void compile_rule:: + gcc_module_mapper (module_mapper_state& st, + action a, const scope& bs, file& t, linfo li, + ifdstream& is, + ofdstream& os, + depdb& dd, bool& update, bool& bad_error, + optional<prefix_map>& pfx_map, srcout_map& so_map) const + { + tracer trace (x, "compile_rule::gcc_module_mapper"); + + // Read in the request line. + // + // Because the dynamic mapper is only used during preprocessing, we + // can assume there is no batching and expect to see one line at a + // time. + // + string rq; +#if 1 + if (!eof (getline (is, rq))) + { + if (rq.empty ()) + rq = "<empty>"; // Not to confuse with EOF. + } +#else + for (char buf[4096]; !is.eof (); ) + { + streamsize n (is.readsome (buf, sizeof (buf) - 1)); + buf[n] = '\0'; + + if (char* p = strchr (buf, '\n')) + { + *p = '\0'; + + if (++p != buf + n) + fail << "batched module mapper request: '" << p << "'"; + + rq += buf; + break; + } + else + rq += buf; + } +#endif + + if (rq.empty ()) // EOF + return; + + // @@ MODHDR: Should we print the pid we are talking to? It gets hard to + // follow once things get nested. But if all our diag will + // include some kind of id (chain, thread?), then this will + // not be strictly necessary. + // + if (verb >= 3) + text << " > " << rq; + + // Check for a command. If match, remove it and the following space from + // the request string saving it in cmd (for diagnostics) unless the + // second argument is false, and return true. + // + const char* cmd (nullptr); + auto command = [&rq, &cmd] (const char* c, bool r = true) + { + size_t n (strlen (c)); + bool m (rq.compare (0, n, c) == 0 && rq[n] == ' '); + + if (m && r) + { + cmd = c; + rq.erase (0, n + 1); + } + + return m; + }; + + string rs; + for (;;) // Breakout loop. + { + // Each command is reponsible for handling its auxiliary data while we + // just clear it. + // + string data (move (st.data)); + + if (command ("HELLO")) + { + // HELLO <ver> <kind> <ident> + // + //@@ MODHDR TODO: check protocol version. + + // We don't use "repository path" (whatever it is) so we pass '.'. + // + rs = "HELLO 0 build2 ."; + } + // + // Turns out it's easiest to handle IMPORT together with INCLUDE since + // it can also trigger a re-search, etc. In a sense, IMPORT is all of + // the INCLUDE logic (skipping translation) plus the BMI dependency + // synthesis. + // + else if (command ("INCLUDE") || command ("IMPORT")) + { + // INCLUDE [<"']<name>[>"'] <path> + // IMPORT [<"']<name>[>"'] <path> + // IMPORT '<path>' + // + // <path> is the resolved path or empty if the header is not found. + // It can be relative if it is derived from a relative path (either + // via -I or includer). If <name> is single-quoted, then it cannot + // be re-searched (e.g., implicitly included stdc-predef.h) and in + // this case <path> is never empty. + // + // In case of re-search or include translation we may have to split + // handling the same include or import across multiple commands. + // Here are the scenarios in question: + // + // INCLUDE --> SEARCH -?-> INCLUDE + // IMPORT --> SEARCH -?-> IMPORT + // INCLUDE --> IMPORT -?-> IMPORT + // + // The problem is we may not necessarily get the "followup" command + // (the question marks above). We may not get the followup after + // SEARCH because, for example, the newly found header has already + // been included/imported using a different style/path. Similarly, + // the IMPORT response may not be followed up with the IMPORT + // command because this header has already been imported, for + // example, using an import declaration. Throw into this #pragma + // once, include guards, and how exactly the compiler deals with + // them and things become truly unpredictable and hard to reason + // about. As a result, for each command we have to keep the build + // state consistent, specifically, without any "dangling" matched + // targets (which would lead to skew dependency counts). Note: the + // include translation is no longer a problem since we respond with + // an immediate BMI. + // + // To keep things simple we are going to always add a target that we + // matched to our prerequisite_targets. This includes the header + // target when building the BMI: while not ideal, this should be + // harmless provided we don't take its state/mtime into account. + // + // One thing we do want to handle specially is the "maybe-followup" + // case discussed above. It is hard to distinguish from an unrelated + // INCLUDE/IMPORT (we could have saved <name> and maybe correlated + // based on that). But if we don't, then we will keep matching and + // adding each target twice. What we can do, however, is check + // whether this target is already in prerequisite_targets and skip + // it if that's the case, which is a valid thing to do whether it is + // a followup or an unrelated command. In fact, for a followup, we + // only need to check the last element in prerequisite_targets. + // + // This approach strikes a reasonable balance between keeping things + // simple and handling normal cases without too much overhead. Note + // that we may still end up matching and adding the same targets + // multiple times for pathological cases, like when the same header + // is included using a different style/path, etc. We could, however, + // take care of this by searching the entire prerequisite_targets, + // which is always an option (and which would probably be required + // if the compiler were to send the INCLUDE command before checking + // for #pragma once or include guards, which GCC does not do). + // + // One thing that we cannot do without distinguishing followup and + // unrelated commands is verify the remapped header found by the + // compiler resolves to the expected target. So we will also do the + // correlation via <name>. + // + bool imp (cmd[1] == 'M'); + + path f; // <path> or <name> if doesn't exist + string n; // [<"']<name>[>"'] + bool exists; // <path> is not empty + bool searchable; // <name> is not single-quoted + { + char q (rq[0]); // Opening quote. + q = (q == '<' ? '>' : + q == '"' ? '"' : + q == '\'' ? '\'' : '\0'); // Closing quote. + + size_t s (rq.size ()), qp; // Quote position. + if (q == '\0' || (qp = rq.find (q, 1)) == string::npos) + break; // Malformed command. + + n.assign (rq, 0, qp + 1); + + size_t p (qp + 1); + if (imp && q == '\'' && p == s) // IMPORT '<path>' + { + exists = true; + // Leave f empty and fall through. + } + else + { + if (p != s && rq[p++] != ' ') // Skip following space, if any. + break; + + exists = (p != s); + + if (exists) + { + rq.erase (0, p); + f = path (move (rq)); + assert (!f.empty ()); + } + //else // Leave f empty and fall through. + } + + if (f.empty ()) + { + rq.erase (0, 1); // Opening quote. + rq.erase (qp - 1); // Closing quote and trailing space, if any. + f = path (move (rq)); + } + + // Complete relative paths not to confuse with non-existent. + // + if (exists && !f.absolute ()) + f.complete (); + + searchable = (q != '\''); + } + + // The skip_count logic: in a nutshell (and similar to the non- + // mapper case), we may have "processed" some portion of the headers + // based on the depdb cache and we need to avoid re-processing them + // here. See the skip_count discussion for details. + // + // Note also that we need to be careful not to decrementing the + // count for re-searches and include translation. + // + bool skip (st.skip != 0); + + // The first part is the same for both INCLUDE and IMPORT: resolve + // the header path to target, update it, and trigger re-search if + // necessary. + // + const file* ht (nullptr); + auto& pts (t.prerequisite_targets[a]); + + // If this is a followup command (or indistinguishable from one), + // then as a sanity check verify the header found by the compiler + // resolves to the expected target. + // + if (data == n) + { + assert (!skip); // We shouldn't be re-searching while skipping. + + if (exists) + { + pair<const file*, bool> r ( + enter_header (a, bs, t, li, + move (f), false /* cache */, + pfx_map, so_map)); + + if (!r.second) // Shouldn't be remapped. + ht = r.first; + } + + if (ht != pts.back ()) + { + ht = static_cast<const file*> (pts.back ().target); + rs = "ERROR expected header '" + ht->path ().string () + + "' to be found instead"; + bad_error = true; // We expect an error from the compiler. + break; + } + + // Fall through. + } + else + { + // Enter, update, and see if we need to re-search this header. + // + bool updated (false), remapped; + try + { + pair<const file*, bool> er ( + enter_header (a, bs, t, li, + move (f), false /* cache */, + pfx_map, so_map)); + + ht = er.first; + remapped = er.second; + + if (remapped && !searchable) + { + rs = "ERROR remapping non-re-searchable header " + n; + bad_error = true; + break; + } + + // If we couldn't enter this header as a target (as opposed to + // not finding a rule to update it), then our diagnostics won't + // really add anything to the compiler's. + // + if (ht == nullptr) + { + assert (!exists); // Sanity check. + throw failed (); + } + + // Note that we explicitly update even for IMPORT (instead of, + // say, letting the BMI rule do it implicitly) since we may need + // to cause a re-search (see below). + // + if (!skip) + { + if (pts.empty () || pts.back () != ht) + { + optional<bool> ir (inject_header (a, t, + *ht, false /* cache */, + timestamp_unknown)); + assert (ir); // Not from cache. + updated = *ir; + } + else + assert (exists); + } + else + assert (exists && !remapped); // Maybe this should be an error. + } + catch (const failed&) + { + // If the header does not exist or could not be updated, do we + // want our diagnostics, the compiler's, or both? We definitely + // want the compiler's since it points to the exact location. + // Ours could also be helpful. So while it will look a bit + // messy, let's keep both (it would have been nicer to print + // ours after the compiler's but that isn't easy). + // + rs = !exists + ? string ("INCLUDE") + : ("ERROR unable to update header '" + + (ht != nullptr ? ht->path () : f).string () + "'"); + + bad_error = true; + break; + } + + if (!imp) // Indirect prerequisite (see above). + update = updated || update; + + // A mere update is not enough to cause a re-search. It either had + // to also not exist or be remapped. + // + if ((updated && !exists) || remapped) + { + rs = "SEARCH"; + st.data = move (n); // Followup correlation. + break; + } + + // Fall through. + } + + // Now handle INCLUDE and IMPORT differences. + // + const string& hp (ht->path ().string ()); + + // Reduce include translation to the import case. + // + if (!imp && import_hdr != nullptr) + { + const strings& ih (*import_hdr); + + auto i (lower_bound (ih.begin (), + ih.end (), + hp, + [] (const string& x, const string& y) + { + return path::traits_type::compare (x, y) < 0; + })); + + imp = (i != ih.end () && *i == hp); + } + + if (imp) + { + try + { + // Synthesize the BMI dependency then update and add the BMI + // target as a prerequisite. + // + const file& bt (make_header_sidebuild (a, bs, li, *ht)); + + if (!skip) + { + optional<bool> ir (inject_header (a, t, + bt, false /* cache */, + timestamp_unknown)); + assert (ir); // Not from cache. + update = *ir || update; + } + + const string& bp (bt.path ().string ()); + + if (!skip) + { + // @@ MODHDR: we write normalized path while the compiler will + // look for the original. In particular, this means + // that paths with `..` won't work. Maybe write + // original for mapping and normalized for our use? + // + st.headers++; + dd.expect ("@ '" + hp + "' " + bp); + } + else + st.skip--; + + rs = "IMPORT " + bp; + } + catch (const failed&) + { + rs = "ERROR unable to update header unit '" + hp + "'"; + bad_error = true; + break; + } + } + else + { + if (!skip) + dd.expect (hp); + else + st.skip--; + + rs = "INCLUDE"; + } + } + + break; + } + + if (rs.empty ()) + { + rs = "ERROR unexpected command '"; + + if (cmd != nullptr) + { + rs += cmd; // Add the command back. + rs += ' '; + } + + rs += rq; + rs += "'"; + + bad_error = true; + } + + if (verb >= 3) + text << " < " << rs; + + os << rs << endl; + } + + // Enter as a target a header file. Depending on the cache flag, the file + // is assumed to either have come from the depdb cache or from the + // compiler run. + // + // Return the header target and an indication of whether it was remapped + // or NULL if the header does not exist and cannot be generated. In the + // latter case the passed header path is guaranteed to be still valid but + // might have been adjusted (e.g., normalized, etc). + // + // Note: this used to be a lambda inside extract_headers() so refer to the + // body of that function for the overall picture. + // + pair<const file*, bool> compile_rule:: + enter_header (action a, const scope& bs, file& t, linfo li, + path&& f, bool cache, + optional<prefix_map>& pfx_map, srcout_map& so_map) const + { + tracer trace (x, "compile_rule::enter_header"); + + // Find or maybe insert the target. The directory is only moved from if + // insert is true. + // + auto find = [&trace, &t, this] (dir_path&& d, + path&& f, + bool insert) -> const file* + { + // Split the file into its name part and extension. Here we can assume + // the name part is a valid filesystem name. + // + // Note that if the file has no extension, we record an empty + // extension rather than NULL (which would signify that the default + // extension should be added). + // + string e (f.extension ()); + string n (move (f).string ()); + + if (!e.empty ()) + n.resize (n.size () - e.size () - 1); // One for the dot. + + // See if this directory is part of any project out_root hierarchy and + // if so determine the target type. + // + // Note that this will miss all the headers that come from src_root + // (so they will be treated as generic C headers below). Generally, we + // don't have the ability to determine that some file belongs to + // src_root of some project. But that's not a problem for our + // purposes: it is only important for us to accurately determine + // target types for headers that could be auto-generated. + // + // While at it also try to determine if this target is from the src or + // out tree of said project. + // + dir_path out; + + // It's possible the extension-to-target type mapping is ambiguous + // (usually because both C and X-language headers use the same .h + // extension). In this case we will first try to find one that matches + // an explicit target (similar logic to when insert is false). + // + small_vector<const target_type*, 2> tts; + + const scope& bs (t.ctx.scopes.find (d)); + if (const scope* rs = bs.root_scope ()) + { + tts = map_extension (bs, n, e); + + if (bs.out_path () != bs.src_path () && d.sub (bs.src_path ())) + out = out_src (d, *rs); + } + + // If it is outside any project, or the project doesn't have such an + // extension, assume it is a plain old C header. + // + if (tts.empty ()) + { + // If the project doesn't "know" this extension then we can't + // possibly find an explicit target of this type. + // + if (!insert) + return nullptr; + + tts.push_back (&h::static_type); + } + + // Find or insert target. + // + // Note that in case of the target type ambiguity we first try to find + // an explicit target that resolves this ambiguity. + // + const target* r (nullptr); + + if (!insert || tts.size () > 1) + { + // Note that we skip any target type-specific searches (like for an + // existing file) and go straight for the target object since we + // need to find the target explicitly spelled out. + // + // Also, it doesn't feel like we should be able to resolve an + // absolute path with a spelled-out extension to multiple targets. + // + for (const target_type* tt: tts) + if ((r = t.ctx.targets.find (*tt, d, out, n, e, trace)) != nullptr) + break; + + // Note: we can't do this because of the in-source builds where + // there won't be explicit targets for non-generated headers. + // + // This should be harmless, however, since in our world generated + // headers are normally spelled-out as explicit targets. And if not, + // we will still get an error, just a bit less specific. + // +#if 0 + if (r == nullptr && insert) + { + f = d / n; + if (!e.empty ()) + { + f += '.'; + f += e; + } + + diag_record dr (fail); + dr << "mapping of header " << f << " to target type is ambiguous"; + for (const target_type* tt: tts) + dr << info << "could be " << tt->name << "{}"; + dr << info << "spell-out its target to resolve this ambiguity"; + } +#endif + } + + // @@ OPT: move d, out, n + // + if (r == nullptr && insert) + r = &search (t, *tts[0], d, out, n, &e, nullptr); + + return static_cast<const file*> (r); + }; + + // If it's not absolute then it either does not (yet) exist or is a + // relative ""-include (see init_args() for details). Reduce the second + // case to absolute. + // + // Note: we now always use absolute path to the translation unit so this + // no longer applies. But let's keep it for posterity. + // +#if 0 + if (f.relative () && rels.relative ()) + { + // If the relative source path has a directory component, make sure + // it matches since ""-include will always start with that (none of + // the compilers we support try to normalize this path). Failed that + // we may end up searching for a generated header in a random + // (working) directory. + // + const string& fs (f.string ()); + const string& ss (rels.string ()); + + size_t p (path::traits::rfind_separator (ss)); + + if (p == string::npos || // No directory. + (fs.size () > p + 1 && + path::traits::compare (fs.c_str (), p, ss.c_str (), p) == 0)) + { + path t (work / f); // The rels path is relative to work. + + if (exists (t)) + f = move (t); + } + } +#endif + + const file* pt (nullptr); + bool remapped (false); + + // If still relative then it does not exist. + // + if (f.relative ()) + { + // This is probably as often an error as an auto-generated file, so + // trace at level 4. + // + l4 ([&]{trace << "non-existent header '" << f << "'";}); + + f.normalize (); + + // The relative path might still contain '..' (e.g., ../foo.hxx; + // presumably ""-include'ed). We don't attempt to support auto- + // generated headers with such inclusion styles. + // + if (f.normalized ()) + { + if (!pfx_map) + pfx_map = build_prefix_map (bs, a, t, li); + + // First try the whole file. Then just the directory. + // + // @@ Has to be a separate map since the prefix can be the same as + // the file name. + // + // auto i (pfx_map->find (f)); + + // Find the most qualified prefix of which we are a sub-path. + // + if (!pfx_map->empty ()) + { + dir_path d (f.directory ()); + auto i (pfx_map->find_sup (d)); + + if (i != pfx_map->end ()) + { + const dir_path& pd (i->second.directory); + + l4 ([&]{trace << "prefix '" << d << "' mapped to " << pd;}); + + // If this is a prefixless mapping, then only use it if we can + // resolve it to an existing target (i.e., it is explicitly + // spelled out in a buildfile). + // + // Note that at some point we will probably have a list of + // directories. + // + pt = find (pd / d, f.leaf (), !i->first.empty ()); + if (pt != nullptr) + { + f = pd / f; + l4 ([&]{trace << "mapped as auto-generated " << f;}); + } + else + l4 ([&]{trace << "no explicit target in " << pd;}); + } + else + l4 ([&]{trace << "no prefix map entry for '" << d << "'";}); + } + else + l4 ([&]{trace << "prefix map is empty";}); + } + } + else + { + // We used to just normalize the path but that could result in an + // invalid path (e.g., for some system/compiler headers on CentOS 7 + // with Clang 3.4) because of the symlinks (if a directory component + // is a symlink, then any following `..` are resolved relative to the + // target; see path::normalize() for background). + // + // Initially, to fix this, we realized (i.e., realpath(3)) it instead. + // But that turned out also not to be quite right since now we have + // all the symlinks resolved: conceptually it feels correct to keep + // the original header names since that's how the user chose to + // arrange things and practically this is how the compilers see/report + // them (e.g., the GCC module mapper). + // + // So now we have a pretty elaborate scheme where we try to use the + // normalized path if possible and fallback to realized. Normalized + // paths will work for situations where `..` does not cross symlink + // boundaries, which is the sane case. And for the insane case we only + // really care about out-of-project files (i.e., system/compiler + // headers). In other words, if you have the insane case inside your + // project, then you are on your own. + // + // All of this is unless the path comes from the depdb, in which case + // we've already done that. This is also where we handle src-out remap + // (again, not needed if cached). + // + if (!cache) + { + // Interestingly, on most paltforms and with most compilers (Clang + // on Linux being a notable exception) most system/compiler headers + // are already normalized. + // + path_abnormality a (f.abnormalities ()); + if (a != path_abnormality::none) + { + // While we can reasonably expect this path to exit, things do go + // south from time to time (like compiling under wine with file + // wlantypes.h included as WlanTypes.h). + // + try + { + // If we have any parent components, then we have to verify the + // normalized path matches realized. + // + path r; + if ((a & path_abnormality::parent) == path_abnormality::parent) + { + r = f; + r.realize (); + } + + try + { + f.normalize (); + + // Note that we might still need to resolve symlinks in the + // normalized path. + // + if (!r.empty () && f != r && path (f).realize () != r) + f = move (r); + } + catch (const invalid_path&) + { + assert (!r.empty ()); // Shouldn't have failed if no `..`. + f = move (r); // Fallback to realize. + } + } + catch (const invalid_path&) + { + fail << "invalid header path '" << f.string () << "'"; + } + catch (const system_error& e) + { + fail << "invalid header path '" << f.string () << "': " << e; + } + } + + if (!so_map.empty ()) + { + // Find the most qualified prefix of which we are a sub-path. + // + auto i (so_map.find_sup (f)); + if (i != so_map.end ()) + { + // Ok, there is an out tree for this headers. Remap to a path + // from the out tree and see if there is a target for it. + // + dir_path d (i->second); + d /= f.leaf (i->first).directory (); + pt = find (move (d), f.leaf (), false); // d is not moved from. + + if (pt != nullptr) + { + path p (d / f.leaf ()); + l4 ([&]{trace << "remapping " << f << " to " << p;}); + f = move (p); + remapped = true; + } + } + } + } + + if (pt == nullptr) + { + l6 ([&]{trace << "entering " << f;}); + pt = find (f.directory (), f.leaf (), true); + } + } + + return make_pair (pt, remapped); + } + + // Update and add (unless add is false) to the list of prerequisite + // targets a header or header unit target. Depending on the cache flag, + // the target is assumed to either have come from the depdb cache or from + // the compiler run. + // + // Return the indication of whether it has changed or, if the passed + // timestamp is not timestamp_unknown, is older than the target. If the + // header came from the cache and it no longer exists nor can be + // generated, then return nullopt. + // + // Note: this used to be a lambda inside extract_headers() so refer to the + // body of that function for the overall picture. + // + optional<bool> compile_rule:: + inject_header (action a, file& t, + const file& pt, bool cache, timestamp mt) const + { + tracer trace (x, "compile_rule::inject_header"); + + // Match to a rule. + // + // If we are reading the cache, then it is possible the file has since + // been removed (think of a header in /usr/local/include that has been + // uninstalled and now we need to use one from /usr/include). This will + // lead to the match failure which we translate to a restart. + // + if (!cache) + build2::match (a, pt); + else if (!build2::try_match (a, pt).first) + return nullopt; + + bool r (update (trace, a, pt, mt)); + + // Add to our prerequisite target list. + // + t.prerequisite_targets[a].push_back (&pt); + + return r; + } + + // Extract and inject header dependencies. Return the preprocessed source + // file as well as an indication if it is usable for compilation (see + // below for details). + // + // This is also the place where we handle header units which are a lot + // more like auto-generated headers than modules. In particular, if a + // header unit BMI is out-of-date, then we have to re-preprocess this + // translation unit. + // + pair<auto_rmfile, bool> compile_rule:: + extract_headers (action a, + const scope& bs, + file& t, + linfo li, + const file& src, + match_data& md, + depdb& dd, + bool& update, + timestamp mt) const + { + tracer trace (x, "compile_rule::extract_headers"); + + otype ot (li.type); + + bool reprocess (cast_false<bool> (t[c_reprocess])); + + auto_rmfile psrc; + bool puse (true); + + // If things go wrong (and they often do in this area), give the user a + // bit extra context. + // + auto df = make_diag_frame ( + [&src](const diag_record& dr) + { + if (verb != 0) + dr << info << "while extracting header dependencies from " << src; + }); + + const scope& rs (*bs.root_scope ()); + + // Preprocesor mode that preserves as much information as possible while + // still performing inclusions. Also serves as a flag indicating whether + // this compiler uses the separate preprocess and compile setup. + // + const char* pp (nullptr); + + switch (ctype) + { + case compiler_type::gcc: + { + // -fdirectives-only is available since GCC 4.3.0. + // + if (cmaj > 4 || (cmaj == 4 && cmin >= 3)) + pp = "-fdirectives-only"; + + break; + } + case compiler_type::clang: + { + // -frewrite-includes is available since vanilla Clang 3.2.0. + // + // Apple Clang 5.0 is based on LLVM 3.3svn so it should have this + // option (4.2 is based on 3.2svc so it may or may not have it and, + // no, we are not going to try to find out). + // + if (cvariant == "apple" + ? (cmaj >= 5) + : (cmaj > 3 || (cmaj == 3 && cmin >= 2))) + pp = "-frewrite-includes"; + + break; + } + case compiler_type::msvc: + { + // Asking MSVC to preserve comments doesn't really buy us anything + // but does cause some extra buggy behavior. + // + //pp = "/C"; + break; + } + case compiler_type::icc: + break; + } + + // Initialize lazily, only if required. + // + environment env; + cstrings args; + string out; // Storage. + + // Some compilers in certain modes (e.g., when also producing the + // preprocessed output) are incapable of writing the dependecy + // information to stdout. In this case we use a temporary file. + // + auto_rmfile drm; + + // Here is the problem: neither GCC nor Clang allow -MG (treat missing + // header as generated) when we produce any kind of other output (-MD). + // And that's probably for the best since otherwise the semantics gets + // pretty hairy (e.g., what is the exit code and state of the output)? + // + // One thing to note about generated headers: if we detect one, then, + // after generating it, we re-run the compiler since we need to get + // this header's dependencies. + // + // So this is how we are going to work around this problem: we first run + // with -E but without -MG. If there are any errors (maybe because of + // generated headers maybe not), we restart with -MG and without -E. If + // this fixes the error (so it was a generated header after all), then + // we have to restart at which point we go back to -E and no -MG. And we + // keep yo-yoing like this. Missing generated headers will probably be + // fairly rare occurrence so this shouldn't be too expensive. + // + // Actually, there is another error case we would like to handle: an + // outdated generated header that is now causing an error (e.g., because + // of a check that is now triggering #error or some such). So there are + // actually three error cases: outdated generated header, missing + // generated header, and some other error. To handle the outdated case + // we need the compiler to produce the dependency information even in + // case of an error. Clang does it, for VC we parse diagnostics + // ourselves, but GCC does not (but a patch has been submitted). + // + // So the final plan is then as follows: + // + // 1. Start wothout -MG and with suppressed diagnostics. + // 2. If error but we've updated a header, then repeat step 1. + // 3. Otherwise, restart with -MG and diagnostics. + // + // Note that below we don't even check if the compiler supports the + // dependency info on error. We just try to use it and if it's not + // there we ignore the io error since the compiler has failed. + // + bool args_gen; // Current state of args. + size_t args_i (0); // Start of the -M/-MD "tail". + + // Ok, all good then? Not so fast, the rabbit hole is deeper than it + // seems: When we run with -E we have to discard diagnostics. This is + // not a problem for errors since they will be shown on the re-run but + // it is for (preprocessor) warnings. + // + // Clang's -frewrite-includes is nice in that it preserves the warnings + // so they will be shown during the compilation of the preprocessed + // source. They are also shown during -E but that we discard. And unlike + // GCC, in Clang -M does not imply -w (disable warnings) so it would + // have been shown in -M -MG re-runs but we suppress that with explicit + // -w. All is good in the Clang land then (even -Werror works nicely). + // + // GCC's -fdirective-only, on the other hand, processes all the + // directives so they are gone from the preprocessed source. Here is + // what we are going to do to work around this: we will detect if any + // diagnostics has been written to stderr on the -E run. If that's the + // case (but the compiler indicated success) then we assume they are + // warnings and disable the use of the preprocessed output for + // compilation. This in turn will result in compilation from source + // which will display the warnings. Note that we may still use the + // preprocessed output for other things (e.g., C++ module dependency + // discovery). BTW, another option would be to collect all the + // diagnostics and then dump it if the run is successful, similar to + // the VC semantics (and drawbacks) described below. + // + // Finally, for VC, things are completely different: there is no -MG + // equivalent and we handle generated headers by analyzing the + // diagnostics. This means that unlike in the above two cases, the + // preprocessor warnings are shown during dependency extraction, not + // compilation. Not ideal but that's the best we can do. Or is it -- we + // could implement ad hoc diagnostics sensing... It appears warnings are + // in the C4000-C4999 code range though there can also be note lines + // which don't have any C-code. + // + // BTW, triggering a warning in the VC preprocessor is not easy; there + // is no #warning and pragmas are passed through to the compiler. One + // way to do it is to redefine a macro, for example: + // + // hello.cxx(4): warning C4005: 'FOO': macro redefinition + // hello.cxx(3): note: see previous definition of 'FOO' + // + // So seeing that it is hard to trigger a legitimate VC preprocessor + // warning, for now, we will just treat them as errors by adding /WX. + // + // Finally, if we are using the module mapper, then all this mess falls + // away: we only run the compiler once, we let the diagnostics through, + // we get a compiler error (with location information) if a header is + // not found, and there is no problem with outdated generated headers + // since we update/remap them before the compiler has a chance to read + // them. Overall, this "dependency mapper" approach is how it should + // have been done from the beginning. + + // Note: diagnostics sensing is currently only supported if dependency + // info is written to a file (see above). + // + bool sense_diag (false); + + // And here is another problem: if we have an already generated header + // in src and the one in out does not yet exist, then the compiler will + // pick the one in src and we won't even notice. Note that this is not + // only an issue with mixing in- and out-of-tree builds (which does feel + // wrong but is oh so convenient): this is also a problem with + // pre-generated headers, a technique we use to make installing the + // generator by end-users optional by shipping pre-generated headers. + // + // This is a nasty problem that doesn't seem to have a perfect solution + // (except, perhaps, C++ modules). So what we are going to do is try to + // rectify the situation by detecting and automatically remapping such + // mis-inclusions. It works as follows. + // + // First we will build a map of src/out pairs that were specified with + // -I. Here, for performance and simplicity, we will assume that they + // always come in pairs with out first and src second. We build this + // map lazily only if we are running the preprocessor and reuse it + // between restarts. + // + // With the map in hand we can then check each included header for + // potentially having a doppelganger in the out tree. If this is the + // case, then we calculate a corresponding header in the out tree and, + // (this is the most important part), check if there is a target for + // this header in the out tree. This should be fairly accurate and not + // require anything explicit from the user except perhaps for a case + // where the header is generated out of nothing (so there is no need to + // explicitly mention its target in the buildfile). But this probably + // won't be very common. + // + // One tricky area in this setup are target groups: if the generated + // sources are mentioned in the buildfile as a group, then there might + // be no header target (yet). The way we solve this is by requiring code + // generator rules to cooperate and create at least the header target as + // part of the group creation. While not all members of the group may be + // generated depending on the options (e.g., inline files might be + // suppressed), headers are usually non-optional. + // + // Note that we use path_map instead of dir_path_map to allow searching + // using path (file path). + // + srcout_map so_map; // path_map<dir_path> + + // Dynamic module mapper. + // + bool mod_mapper (false); + + // The gen argument to init_args() is in/out. The caller signals whether + // to force the generated header support and on return it signals + // whether this support is enabled. The first call to init_args is + // expected to have gen false. + // + // Return NULL if the dependency information goes to stdout and a + // pointer to the temporary file path otherwise. + // + auto init_args = [a, &t, ot, li, reprocess, + &src, &md, &psrc, &sense_diag, &mod_mapper, + &rs, &bs, + pp, &env, &args, &args_gen, &args_i, &out, &drm, + &so_map, this] + (bool& gen) -> const path* + { + const path* r (nullptr); + + if (args.empty ()) // First call. + { + assert (!gen); + + // We use absolute/relative paths in the dependency output to + // distinguish existing headers from (missing) generated. Which + // means we have to (a) use absolute paths in -I and (b) pass + // absolute source path (for ""-includes). That (b) is a problem: + // if we use an absolute path, then all the #line directives will be + // absolute and all the diagnostics will have long, noisy paths + // (actually, we will still have long paths for diagnostics in + // headers). + // + // To work around this we used to pass a relative path to the source + // file and then check every relative path in the dependency output + // for existence in the source file's directory. This is not without + // issues: it is theoretically possible for a generated header that + // is <>-included and found via -I to exist in the source file's + // directory. Note, however, that this is a lot more likely to + // happen with prefix-less inclusion (e.g., <foo>) and in this case + // we assume the file is in the project anyway. And if there is a + // conflict with a prefixed include (e.g., <bar/foo>), then, well, + // we will just have to get rid of quoted includes (which are + // generally a bad idea, anyway). + // + // But then this approach (relative path) fell apart further when we + // tried to implement precise changed detection: the preprocessed + // output would change depending from where it was compiled because + // of #line (which we could work around) and __FILE__/assert() + // (which we can't really do anything about). So it looks like using + // the absolute path is the lesser of all the evils (and there are + // many). + // + // Note that we detect and diagnose relative -I directories lazily + // when building the include prefix map. + // + args.push_back (cpath.recall_string ()); + + // If we are re-processing the translation unit, then allow the + // translation unit to detect header/module dependency extraction. + // This can be used to work around separate preprocessing bugs in + // the compiler. + // + if (reprocess) + args.push_back ("-D__build2_preprocess"); + + append_options (args, t, c_poptions); + append_options (args, t, x_poptions); + + // Add *.export.poptions from prerequisite libraries. + // + append_lib_options (bs, args, a, t, li); + + // Populate the src-out with the -I$out_base -I$src_base pairs. + // + { + // Try to be fast and efficient by reusing buffers as much as + // possible. + // + string ds; + + // Previous -I innermost scope if out_base plus the difference + // between the scope path and the -I path (normally empty). + // + const scope* s (nullptr); + dir_path p; + + for (auto i (args.begin ()), e (args.end ()); i != e; ++i) + { + // -I can either be in the "-Ifoo" or "-I foo" form. For VC it + // can also be /I. + // + const char* o (*i); + size_t n (strlen (o)); + + if (n < 2 || (o[0] != '-' && o[0] != '/') || o[1] != 'I') + { + s = nullptr; + continue; + } + + if (n == 2) + { + if (++i == e) + break; // Let the compiler complain. + + ds = *i; + } + else + ds.assign (o + 2, n - 2); + + if (!ds.empty ()) + { + // Note that we don't normalize the paths since it would be + // quite expensive and normally the pairs we are inerested in + // are already normalized (since they are usually specified as + // -I$src/out_*). We just need to add a trailing directory + // separator if it's not already there. + // + if (!dir_path::traits_type::is_separator (ds.back ())) + ds += dir_path::traits_type::directory_separator; + + dir_path d (move (ds), dir_path::exact); // Move the buffer in. + + // Ignore invalid paths (buffer is not moved). + // + if (!d.empty ()) + { + // Ignore any paths containing '.', '..' components. Allow + // any directory separators thought (think -I$src_root/foo + // on Windows). + // + if (d.absolute () && d.normalized (false)) + { + // If we have a candidate out_base, see if this is its + // src_base. + // + if (s != nullptr) + { + const dir_path& bp (s->src_path ()); + + if (d.sub (bp)) + { + if (p.empty () || d.leaf (bp) == p) + { + // We've got a pair. + // + so_map.emplace (move (d), s->out_path () / p); + s = nullptr; // Taken. + continue; + } + } + + // Not a pair. Fall through to consider as out_base. + // + s = nullptr; + } + + // See if this path is inside a project with an out-of- + // tree build and is in the out directory tree. + // + const scope& bs (t.ctx.scopes.find (d)); + if (bs.root_scope () != nullptr) + { + const dir_path& bp (bs.out_path ()); + if (bp != bs.src_path ()) + { + bool e; + if ((e = (d == bp)) || d.sub (bp)) + { + s = &bs; + if (e) + p.clear (); + else + p = d.leaf (bp); + } + } + } + } + else + s = nullptr; + + ds = move (d).string (); // Move the buffer out. + } + else + s = nullptr; + } + else + s = nullptr; + } + } + + // Extra system header dirs (last). + // + assert (sys_inc_dirs_extra <= sys_inc_dirs.size ()); + append_option_values ( + args, "-I", + sys_inc_dirs.begin () + sys_inc_dirs_extra, sys_inc_dirs.end (), + [] (const dir_path& d) {return d.string ().c_str ();}); + + if (md.symexport) + append_symexport_options (args, t); + + // Some compile options (e.g., -std, -m) affect the preprocessor. + // + // Currently Clang supports importing "header modules" even when in + // the TS mode. And "header modules" support macros which means + // imports have to be resolved during preprocessing. Which poses a + // bit of a chicken and egg problem for us. For now, the workaround + // is to remove the -fmodules-ts option when preprocessing. Hopefully + // there will be a "pure modules" mode at some point. + // + // @@ MODHDR Clang: should be solved with the dynamic module mapper + // if/when Clang supports it? + // + + // Don't treat warnings as errors. + // + const char* werror (nullptr); + switch (cclass) + { + case compiler_class::gcc: werror = "-Werror"; break; + case compiler_class::msvc: werror = "/WX"; break; + } + + bool clang (ctype == compiler_type::clang); + + append_options (args, t, c_coptions, werror); + append_options (args, t, x_coptions, werror); + append_options (args, tstd, + tstd.size () - (modules && clang ? 1 : 0)); + + switch (cclass) + { + case compiler_class::msvc: + { + args.push_back ("/nologo"); + + // See perform_update() for details on overriding the default + // exceptions and runtime. + // + if (x_lang == lang::cxx && !find_option_prefix ("/EH", args)) + args.push_back ("/EHsc"); + + if (!find_option_prefixes ({"/MD", "/MT"}, args)) + args.push_back ("/MD"); + + args.push_back ("/P"); // Preprocess to file. + args.push_back ("/showIncludes"); // Goes to stdout (with diag). + if (pp != nullptr) + args.push_back (pp); // /C (preserve comments). + args.push_back ("/WX"); // Warning as error (see above). + + msvc_sanitize_cl (args); + + psrc = auto_rmfile (t.path () + x_pext); + + if (cast<uint64_t> (rs[x_version_major]) >= 18) + { + args.push_back ("/Fi:"); + args.push_back (psrc.path.string ().c_str ()); + } + else + { + out = "/Fi" + psrc.path.string (); + args.push_back (out.c_str ()); + } + + append_lang_options (args, md); // Compile as. + gen = args_gen = true; + break; + } + case compiler_class::gcc: + { + if (ot == otype::s) + { + // On Darwin, Win32 -fPIC is the default. + // + if (tclass == "linux" || tclass == "bsd") + args.push_back ("-fPIC"); + } + + // Setup the dynamic module mapper if needed. + // + // Note that it's plausible in the future we will use it even if + // modules are disabled, for example, to implement better -MG. + // In which case it will have probably be better called a + // "dependency mapper". + // + if (modules) + { + if (ctype == compiler_type::gcc) + { + args.push_back ("-fmodule-mapper=<>"); + mod_mapper = true; + } + } + + // Depending on the compiler, decide whether (and how) we can + // produce preprocessed output as a side effect of dependency + // extraction. + // + // Note: -MM -MG skips missing <>-included. + + // Clang's -M does not imply -w (disable warnings). We also + // don't need them in the -MD case (see above) so disable for + // both. + // + if (clang) + args.push_back ("-w"); + + append_lang_options (args, md); + + if (pp != nullptr) + { + // With the GCC module mapper the dependency information is + // written directly to depdb by the mapper. + // + if (ctype == compiler_type::gcc && mod_mapper) + { + // Note that in this mode we don't have -MG re-runs. In a + // sense we are in the -MG mode (or, more precisely, the "no + // -MG required" mode) right away. + // + args.push_back ("-E"); + args.push_back (pp); + gen = args_gen = true; + r = &drm.path; // Bogus/hack to force desired process start. + } + else + { + // Previously we used '*' as a target name but it gets + // expanded to the current directory file names by GCC (4.9) + // that comes with MSYS2 (2.4). Yes, this is the (bizarre) + // behavior of GCC being executed in the shell with -MQ '*' + // option and not just -MQ *. + // + args.push_back ("-MQ"); // Quoted target name. + args.push_back ("^"); // Old versions can't do empty. + + // Note that the options are carefully laid out to be easy + // to override (see below). + // + args_i = args.size (); + + args.push_back ("-MD"); + args.push_back ("-E"); + args.push_back (pp); + + // Dependency output. + // + // GCC until version 8 was not capable of writing the + // dependency information to stdout. We also either need to + // sense the diagnostics on the -E runs (which we currently + // can only do if we don't need to read stdout) or we could + // be communicating with the module mapper via stdin/stdout. + // + if (ctype == compiler_type::gcc) + { + // Use the .t extension (for "temporary"; .d is taken). + // + r = &(drm = auto_rmfile (t.path () + ".t")).path; + } + + args.push_back ("-MF"); + args.push_back (r != nullptr ? r->string ().c_str () : "-"); + + sense_diag = (ctype == compiler_type::gcc); + gen = args_gen = false; + } + + // Preprocessor output. + // + psrc = auto_rmfile (t.path () + x_pext); + args.push_back ("-o"); + args.push_back (psrc.path.string ().c_str ()); + } + else + { + args.push_back ("-MQ"); + args.push_back ("^"); + args.push_back ("-M"); + args.push_back ("-MG"); // Treat missing headers as generated. + gen = args_gen = true; + } + + break; + } + } + + args.push_back (src.path ().string ().c_str ()); + args.push_back (nullptr); + + // Note: only doing it here. + // + if (!env.empty ()) + env.push_back (nullptr); + } + else + { + assert (gen != args_gen && args_i != 0); + + size_t i (args_i); + + if (gen) + { + // Overwrite. + // + args[i++] = "-M"; + args[i++] = "-MG"; + args[i++] = src.path ().string ().c_str (); + args[i] = nullptr; + + if (ctype == compiler_type::gcc) + { + sense_diag = false; + } + } + else + { + // Restore. + // + args[i++] = "-MD"; + args[i++] = "-E"; + args[i++] = pp; + args[i] = "-MF"; + + if (ctype == compiler_type::gcc) + { + r = &drm.path; + sense_diag = true; + } + } + + args_gen = gen; + } + + return r; + }; + + // Build the prefix map lazily only if we have non-existent files. + // Also reuse it over restarts since it doesn't change. + // + optional<prefix_map> pfx_map; + + // If any prerequisites that we have extracted changed, then we have to + // redo the whole thing. The reason for this is auto-generated headers: + // the updated header may now include a yet-non-existent header. Unless + // we discover this and generate it (which, BTW, will trigger another + // restart since that header, in turn, can also include auto-generated + // headers), we will end up with an error during compilation proper. + // + // One complication with this restart logic is that we will see a + // "prefix" of prerequisites that we have already processed (i.e., they + // are already in our prerequisite_targets list) and we don't want to + // keep redoing this over and over again. One thing to note, however, is + // that the prefix that we have seen on the previous run must appear + // exactly the same in the subsequent run. The reason for this is that + // none of the files that it can possibly be based on have changed and + // thus it should be exactly the same. To put it another way, the + // presence or absence of a file in the dependency output can only + // depend on the previous files (assuming the compiler outputs them as + // it encounters them and it is hard to think of a reason why would + // someone do otherwise). And we have already made sure that all those + // files are up to date. And here is the way we are going to exploit + // this: we are going to keep track of how many prerequisites we have + // processed so far and on restart skip right to the next one. + // + // And one more thing: most of the time this list of headers would stay + // unchanged and extracting them by running the compiler every time is a + // bit wasteful. So we are going to cache them in the depdb. If the db + // hasn't been invalidated yet (e.g., because the compiler options have + // changed), then we start by reading from it. If anything is out of + // date then we use the same restart and skip logic to switch to the + // compiler run. + // + size_t skip_count (0); + + // Enter as a target, update, and add to the list of prerequisite + // targets a header file. Depending on the cache flag, the file is + // assumed to either have come from the depdb cache or from the compiler + // run. Return true if the extraction process should be restarted. + // + auto add = [a, &bs, &t, li, + &pfx_map, &so_map, + &dd, &skip_count, + this] (path hp, bool cache, timestamp mt) -> bool + { + const file* ht (enter_header (a, bs, t, li, + move (hp), cache, + pfx_map, so_map).first); + if (ht == nullptr) + { + diag_record dr; + dr << fail << "header '" << hp + << "' not found and cannot be generated"; + + if (verb < 4) + dr << info << "re-run with --verbose=4 for more information"; + } + + if (optional<bool> u = inject_header (a, t, *ht, cache, mt)) + { + // Verify/add it to the dependency database. + // + if (!cache) + dd.expect (ht->path ()); + + skip_count++; + return *u; + } + + dd.write (); // Invalidate this line. + return true; + }; + + // As above but for a header unit. Note that currently it is only used + // for the cached case (the other case is handled by the mapper). + // + auto add_unit = [a, &bs, &t, li, + &pfx_map, &so_map, + &dd, &skip_count, &md, + this] (path hp, path bp, timestamp mt) -> bool + { + const file* ht (enter_header (a, bs, t, li, + move (hp), true /* cache */, + pfx_map, so_map).first); + if (ht == nullptr) + fail << "header '" << hp << "' not found and cannot be generated"; + + // Again, looks like we have to update the header explicitly since + // we want to restart rather than fail if it cannot be updated. + // + if (inject_header (a, t, *ht, true /* cache */, mt)) + { + const file& bt (make_header_sidebuild (a, bs, li, *ht)); + + // It doesn't look like we need the cache semantics here since given + // the header, we should be able to build its BMI. In other words, a + // restart is not going to change anything. + // + optional<bool> u (inject_header (a, t, + bt, false /* cache */, mt)); + assert (u); // Not from cache. + + if (bt.path () == bp) + { + md.headers++; + skip_count++; + return *u; + } + } + + dd.write (); // Invalidate this line. + return true; + }; + + // See init_args() above for details on generated header support. + // + bool gen (false); + optional<bool> force_gen; + optional<size_t> force_gen_skip; // Skip count at last force_gen run. + + const path* drmp (nullptr); // Points to drm.path () if active. + + // If nothing so far has invalidated the dependency database, then try + // the cached data before running the compiler. + // + bool cache (!update); + + for (bool restart (true); restart; cache = false) + { + restart = false; + + if (cache) + { + // If any, this is always the first run. + // + assert (skip_count == 0); + + // We should always end with a blank line. + // + for (;;) + { + string* l (dd.read ()); + + // If the line is invalid, run the compiler. + // + if (l == nullptr) + { + restart = true; + break; + } + + if (l->empty ()) // Done, nothing changed. + { + // If modules are enabled, then we keep the preprocessed output + // around (see apply() for details). + // + return modules + ? make_pair (auto_rmfile (t.path () + x_pext, false), true) + : make_pair (auto_rmfile (), false); + } + + // This can be a header or a header unit (mapping). The latter + // is single-quoted. + // + // If this header (unit) came from the depdb, make sure it is no + // older than the target (if it has changed since the target was + // updated, then the cached data is stale). + // + if ((*l)[0] == '@') + { + size_t p (l->find ('\'', 3)); + + if (p != string::npos) + { + path h (*l, 3, p - 3); + path b (move (l->erase (0, p + 2))); + + restart = add_unit (move (h), move (b), mt); + } + else + restart = true; // Corrupt database? + } + else + restart = add (path (move (*l)), true, mt); + + if (restart) + { + update = true; + l6 ([&]{trace << "restarting (cache)";}); + break; + } + } + } + else + { + try + { + if (force_gen) + gen = *force_gen; + + if (args.empty () || gen != args_gen) + drmp = init_args (gen); + + if (verb >= 3) + print_process (args.data ()); // Disable pipe mode. + + process pr; + + try + { + // Assume the preprocessed output (if produced) is usable + // until proven otherwise. + // + puse = true; + + // Save the timestamp just before we start preprocessing. If + // we depend on any header that has been updated since, then + // we should assume we've "seen" the old copy and re-process. + // + timestamp pmt (system_clock::now ()); + + // In some cases we may need to ignore the error return status. + // The good_error flag keeps track of that. Similarly, sometimes + // we expect the error return status based on the output that we + // see. The bad_error flag is for that. + // + bool good_error (false), bad_error (false); + + // If we have no generated header support, then suppress all + // diagnostics (if things go badly we will restart with this + // support). + // + if (drmp == nullptr) // Dependency info goes to stdout. + { + assert (!sense_diag); // Note: could support with fdselect(). + + // For VC with /P the dependency info and diagnostics all go + // to stderr so redirect it to stdout. + // + pr = process ( + cpath, + args.data (), + 0, + -1, + cclass == compiler_class::msvc ? 1 : gen ? 2 : -2, + nullptr, // CWD + env.empty () ? nullptr : env.data ()); + } + else // Dependency info goes to a temporary file. + { + pr = process (cpath, + args.data (), + mod_mapper ? -1 : 0, + mod_mapper ? -1 : 2, // Send stdout to stderr. + gen ? 2 : sense_diag ? -1 : -2, + nullptr, // CWD + env.empty () ? nullptr : env.data ()); + + // Monitor for module mapper requests and/or diagnostics. If + // diagnostics is detected, mark the preprocessed output as + // unusable for compilation. + // + if (mod_mapper || sense_diag) + { + module_mapper_state mm_state (skip_count); + + const char* w (nullptr); + try + { + // For now we don't need to do both so let's use a simpler + // blocking implementation. Note that the module mapper + // also needs to be adjusted when switching to the + // non-blocking version. + // +#if 1 + assert (mod_mapper != sense_diag); + + if (mod_mapper) + { + w = "module mapper request"; + + // Note: the order is important (see the non-blocking + // verison for details). + // + ifdstream is (move (pr.in_ofd), + fdstream_mode::skip, + ifdstream::badbit); + ofdstream os (move (pr.out_fd)); + + do + { + gcc_module_mapper (mm_state, + a, bs, t, li, + is, os, + dd, update, bad_error, + pfx_map, so_map); + } while (!is.eof ()); + + os.close (); + is.close (); + } + + if (sense_diag) + { + w = "diagnostics"; + ifdstream is (move (pr.in_efd), fdstream_mode::skip); + puse = puse && (is.peek () == ifdstream::traits_type::eof ()); + is.close (); + } +#else + fdselect_set fds; + auto add = [&fds] (const auto_fd& afd) -> fdselect_state* + { + int fd (afd.get ()); + fdmode (fd, fdstream_mode::non_blocking); + fds.push_back (fd); + return &fds.back (); + }; + + // Note that while we read both streams until eof in + // normal circumstances, we cannot use fdstream_mode::skip + // for the exception case on both of them: we may end up + // being blocked trying to read one stream while the + // process may be blocked writing to the other. So in case + // of an exception we only skip the diagnostics and close + // the mapper stream hard. The latter should happen first + // so the order of the following variable is important. + // + ifdstream es; + ofdstream os; + ifdstream is; + + fdselect_state* ds (nullptr); + if (sense_diag) + { + w = "diagnostics"; + ds = add (pr.in_efd); + es.open (move (pr.in_efd), fdstream_mode::skip); + } + + fdselect_state* ms (nullptr); + if (mod_mapper) + { + w = "module mapper request"; + ms = add (pr.in_ofd); + is.open (move (pr.in_ofd)); + os.open (move (pr.out_fd)); // Note: blocking. + } + + // Set each state pointer to NULL when the respective + // stream reaches eof. + // + while (ds != nullptr || ms != nullptr) + { + w = "output"; + ifdselect (fds); + + // First read out the diagnostics in case the mapper + // interaction produces more. To make sure we don't get + // blocked by full stderr, the mapper should only handle + // one request at a time. + // + if (ds != nullptr && ds->ready) + { + w = "diagnostics"; + + for (char buf[4096];;) + { + streamsize c (sizeof (buf)); + streamsize n (es.readsome (buf, c)); + + if (puse && n > 0) + puse = false; + + if (n < c) + break; + } + + if (es.eof ()) + { + es.close (); + ds->fd = nullfd; + ds = nullptr; + } + } + + if (ms != nullptr && ms->ready) + { + w = "module mapper request"; + + gcc_module_mapper (mm_state, + a, bs, t, li, + is, os, + dd, update, bad_error, + pfx_map, so_map); + if (is.eof ()) + { + os.close (); + is.close (); + ms->fd = nullfd; + ms = nullptr; + } + } + } +#endif + } + catch (const io_error& e) + { + if (pr.wait ()) + fail << "io error handling " << x_lang << " compiler " + << w << ": " << e; + + // Fall through. + } + + if (mod_mapper) + md.headers += mm_state.headers; + } + + // The idea is to reduce this to the stdout case. + // + pr.wait (); + + // With -MG we want to read dependency info even if there is + // an error (in case an outdated header file caused it). But + // with the GCC module mapper an error is non-negotiable, so + // to speak, and so we want to skip all of that. In fact, we + // now write directly to depdb without generating and then + // parsing an intermadiate dependency makefile. + // + pr.in_ofd = (ctype == compiler_type::gcc && mod_mapper) + ? auto_fd (nullfd) + : fdopen (*drmp, fdopen_mode::in); + } + + if (pr.in_ofd != nullfd) + { + // We may not read all the output (e.g., due to a restart). + // Before we used to just close the file descriptor to signal + // to the other end that we are not interested in the rest. + // This works fine with GCC but Clang (3.7.0) finds this + // impolite and complains, loudly (broken pipe). So now we are + // going to skip until the end. + // + ifdstream is (move (pr.in_ofd), + fdstream_mode::text | fdstream_mode::skip, + ifdstream::badbit); + + size_t skip (skip_count); + string l; // Reuse. + for (bool first (true), second (false); !restart; ) + { + if (eof (getline (is, l))) + break; + + l6 ([&]{trace << "header dependency line '" << l << "'";}); + + // Parse different dependency output formats. + // + switch (cclass) + { + case compiler_class::msvc: + { + if (first) + { + // The first line should be the file we are compiling. + // If it is not, then something went wrong even before + // we could compile anything (e.g., file does not + // exist). In this case the first line (and everything + // after it) is presumably diagnostics. + // + // It can, however, be a command line warning, for + // example: + // + // cl : Command line warning D9025 : overriding '/W3' with '/W4' + // + // So we try to detect and skip them assuming they + // will also show up during the compilation proper. + // + if (l != src.path ().leaf ().string ()) + { + // D8XXX are errors while D9XXX are warnings. + // + size_t p (msvc_sense_diag (l, 'D')); + if (p != string::npos && l[p] == '9') + continue; + + text << l; + bad_error = true; + break; + } + + first = false; + continue; + } + + string f (next_show (l, good_error)); + + if (f.empty ()) // Some other diagnostics. + { + text << l; + bad_error = true; + break; + } + + // Skip until where we left off. + // + if (skip != 0) + { + // We can't be skipping over a non-existent header. + // + assert (!good_error); + skip--; + } + else + { + restart = add (path (move (f)), false, pmt); + + // If the header does not exist (good_error), then + // restart must be true. Except that it is possible + // that someone running in parallel has already + // updated it. In this case we must force a restart + // since we haven't yet seen what's after this + // at-that-time-non-existent header. + // + // We also need to force the target update (normally + // done by add()). + // + if (good_error) + restart = true; + // + // And if we have updated the header (restart is + // true), then we may end up in this situation: an old + // header got included which caused the preprocessor + // to fail down the line. So if we are restarting, set + // the good error flag in case the process fails + // because of something like this (and if it is for a + // valid reason, then we will pick it up on the next + // round). + // + else if (restart) + good_error = true; + + if (restart) + { + update = true; + l6 ([&]{trace << "restarting";}); + } + } + + break; + } + case compiler_class::gcc: + { + // Make dependency declaration. + // + size_t pos (0); + + if (first) + { + // Empty/invalid output should mean the wait() call + // below will return false. + // + if (l.empty () || + l[0] != '^' || l[1] != ':' || l[2] != ' ') + { + // @@ Hm, we don't seem to redirect stderr to stdout + // for this class of compilers so I wonder why + // we are doing this? + // + if (!l.empty ()) + text << l; + + bad_error = true; + break; + } + + first = false; + second = true; + + // While normally we would have the source file on the + // first line, if too long, it will be moved to the + // next line and all we will have on this line is: + // "^: \". + // + if (l.size () == 4 && l[3] == '\\') + continue; + else + pos = 3; // Skip "^: ". + + // Fall through to the 'second' block. + } + + if (second) + { + second = false; + next_make (l, pos); // Skip the source file. + } + + while (pos != l.size ()) + { + string f (next_make (l, pos)); + + // Skip until where we left off. + // + if (skip != 0) + { + skip--; + continue; + } + + restart = add (path (move (f)), false, pmt); + + if (restart) + { + // The same "preprocessor may fail down the line" + // logic as above. + // + good_error = true; + + update = true; + l6 ([&]{trace << "restarting";}); + break; + } + } + + break; + } + } + + if (bad_error) + break; + } + + // In case of VC, we are parsing stderr and if things go + // south, we need to copy the diagnostics for the user to see. + // + if (bad_error && cclass == compiler_class::msvc) + { + // We used to just dump the whole rdbuf but it turns out VC + // may continue writing include notes interleaved with the + // diagnostics. So we have to filter them out. + // + for (; !eof (getline (is, l)); ) + { + size_t p (msvc_sense_diag (l, 'C')); + if (p != string::npos && l.compare (p, 4, "1083") != 0) + diag_stream_lock () << l << endl; + } + } + + is.close (); + + // This is tricky: it is possible that in parallel someone has + // generated all our missing headers and we wouldn't restart + // normally. + // + // In this case we also need to force the target update (which + // is normally done by add()). + // + if (force_gen && *force_gen) + { + restart = update = true; + force_gen = false; + } + } + + if (pr.wait ()) + { + if (!bad_error) // Ignore expected successes (we are done). + continue; + + fail << "expected error exit status from " << x_lang + << " compiler"; + } + else if (pr.exit->normal ()) + { + if (good_error) // Ignore expected errors (restart). + continue; + } + + // Fall through. + } + catch (const io_error& e) + { + if (pr.wait ()) + fail << "unable to read " << x_lang << " compiler header " + << "dependency output: " << e; + + // Fall through. + } + + assert (pr.exit && !*pr.exit); + const process_exit& e (*pr.exit); + + // For normal exit we assume the child process issued some + // diagnostics. + // + if (e.normal ()) + { + // If this run was with the generated header support then we + // have issued diagnostics and it's time to give up. + // + if (gen) + throw failed (); + + // Just to recap, being here means something is wrong with the + // source: it can be a missing generated header, it can be an + // outdated generated header (e.g., some check triggered #error + // which will go away if only we updated the generated header), + // or it can be a real error that is not going away. + // + // So this is what we are going to do here: if anything got + // updated on this run (i.e., the compiler has produced valid + // dependency information even though there were errors and we + // managed to find and update a header based on this + // informaion), then we restart in the same mode hoping that + // this fixes things. Otherwise, we force the generated header + // support which will either uncover a missing generated header + // or will issue diagnostics. + // + if (restart) + l6 ([&]{trace << "trying again without generated headers";}); + else + { + // In some pathological situations we may end up switching + // back and forth indefinitely without making any headway. So + // we use skip_count to track our progress. + // + // Examples that have been encountered so far: + // + // - Running out of disk space. + // + // - Using __COUNTER__ in #if which is incompatible with the + // GCC's -fdirectives-only mode. + // + // - A Clang bug: https://bugs.llvm.org/show_bug.cgi?id=35580 + // + // So let's show the yo-yo'ing command lines and ask the user + // to investigate. + // + // Note: we could restart one more time but this time without + // suppressing diagnostics. This could be useful since, say, + // running out of disk space may not reproduce on its own (for + // example, because we have removed all the partially + // preprocessed source files). + // + if (force_gen_skip && *force_gen_skip == skip_count) + { + diag_record dr (fail); + + dr << "inconsistent " << x_lang << " compiler behavior" << + info << "run the following two commands to investigate"; + + dr << info; + print_process (dr, args.data ()); // No pipes. + + init_args ((gen = true)); + dr << info << ""; + print_process (dr, args.data ()); // No pipes. + } + + restart = true; + force_gen = true; + force_gen_skip = skip_count; + l6 ([&]{trace << "restarting with forced generated headers";}); + } + continue; + } + else + run_finish (args, pr); // Throws. + } + catch (const process_error& e) + { + error << "unable to execute " << args[0] << ": " << e; + + // In a multi-threaded program that fork()'ed but did not exec(), + // it is unwise to try to do any kind of cleanup (like unwinding + // the stack and running destructors). + // + if (e.child) + { + drm.cancel (); + exit (1); + } + + throw failed (); + } + } + } + + // Add the terminating blank line (we are updating depdb). + // + dd.expect (""); + + puse = puse && !reprocess && !psrc.path.empty (); + return make_pair (move (psrc), puse); + } + + // Return the translation unit information (first) and its checksum + // (second). If the checksum is empty, then it should not be used. + // + pair<unit, string> compile_rule:: + parse_unit (action a, + file& t, + linfo li, + const file& src, + auto_rmfile& psrc, + const match_data& md, + const path& dd) const + { + tracer trace (x, "compile_rule::parse_unit"); + + otype ot (li.type); + + // If things go wrong give the user a bit extra context. + // + auto df = make_diag_frame ( + [&src](const diag_record& dr) + { + if (verb != 0) + dr << info << "while parsing " << src; + }); + + // For some compilers (GCC, Clang) the preporcessed output is only + // partially preprocessed. For others (VC), it is already fully + // preprocessed (well, almost: it still has comments but we can handle + // that). Plus, the source file might already be (sufficiently) + // preprocessed. + // + // So the plan is to start the compiler process that writes the fully + // preprocessed output to stdout and reduce the already preprocessed + // case to it. + // + environment env; + cstrings args; + small_vector<string, 2> header_args; // Header unit options storage. + + const path* sp; // Source path. + + // @@ MODHDR: If we are reprocessing, then will need module mapper for + // include translation. Hairy... Can't we add support for + // include translation in file mapper? + // + bool reprocess (cast_false<bool> (t[c_reprocess])); + + bool ps; // True if extracting from psrc. + if (md.pp < preprocessed::modules) + { + // If we were instructed to reprocess the source during compilation, + // then also reprocess it here. While the preprocessed output may be + // usable for our needs, to be safe we assume it is not (and later we + // may extend cc.reprocess to allow specifying where reprocessing is + // needed). + // + ps = !psrc.path.empty () && !reprocess; + sp = &(ps ? psrc.path : src.path ()); + + // VC's preprocessed output, if present, is fully preprocessed. + // + if (cclass != compiler_class::msvc || !ps) + { + // This should match with how we setup preprocessing and is pretty + // similar to init_args() from extract_headers(). + // + args.push_back (cpath.recall_string ()); + + if (reprocess) + args.push_back ("-D__build2_preprocess"); + + append_options (args, t, c_poptions); + append_options (args, t, x_poptions); + + append_lib_options (t.base_scope (), args, a, t, li); + + assert (sys_inc_dirs_extra <= sys_inc_dirs.size ()); + append_option_values ( + args, "-I", + sys_inc_dirs.begin () + sys_inc_dirs_extra, sys_inc_dirs.end (), + [] (const dir_path& d) {return d.string ().c_str ();}); + + if (md.symexport) + append_symexport_options (args, t); + + // Make sure we don't fail because of warnings. + // + // @@ Can be both -WX and /WX. + // + const char* werror (nullptr); + switch (cclass) + { + case compiler_class::gcc: werror = "-Werror"; break; + case compiler_class::msvc: werror = "/WX"; break; + } + + bool clang (ctype == compiler_type::clang); + + append_options (args, t, c_coptions, werror); + append_options (args, t, x_coptions, werror); + append_options (args, tstd, + tstd.size () - (modules && clang ? 1 : 0)); + + append_headers (env, args, header_args, a, t, md, dd); + + switch (cclass) + { + case compiler_class::msvc: + { + args.push_back ("/nologo"); + + if (x_lang == lang::cxx && !find_option_prefix ("/EH", args)) + args.push_back ("/EHsc"); + + if (!find_option_prefixes ({"/MD", "/MT"}, args)) + args.push_back ("/MD"); + + args.push_back ("/E"); + // args.push_back ("/C"); // See above. + + msvc_sanitize_cl (args); + + append_lang_options (args, md); // Compile as. + + break; + } + case compiler_class::gcc: + { + if (ot == otype::s) + { + if (tclass == "linux" || tclass == "bsd") + args.push_back ("-fPIC"); + } + + args.push_back ("-E"); + append_lang_options (args, md); + + // Options that trigger preprocessing of partially preprocessed + // output are a bit of a compiler-specific voodoo. + // + if (ps) + { + if (ctype == compiler_type::gcc) + { + // Note that only these two *plus* -x do the trick. + // + args.push_back ("-fpreprocessed"); + args.push_back ("-fdirectives-only"); + } + } + + break; + } + } + + args.push_back (sp->string ().c_str ()); + args.push_back (nullptr); + } + + if (!env.empty ()) + env.push_back (nullptr); + } + else + { + // Extracting directly from source. + // + ps = false; + sp = &src.path (); + } + + // Preprocess and parse. + // + for (;;) // Breakout loop. + try + { + // Disarm the removal of the preprocessed file in case of an error. + // We re-arm it below. + // + if (ps) + psrc.active = false; + + process pr; + + try + { + if (args.empty ()) + { + pr = process (process_exit (0)); // Successfully exited. + pr.in_ofd = fdopen (*sp, fdopen_mode::in); + } + else + { + if (verb >= 3) + print_process (args); + + // We don't want to see warnings multiple times so ignore all + // diagnostics. + // + pr = process (cpath, + args.data (), + 0, -1, -2, + nullptr, // CWD + env.empty () ? nullptr : env.data ()); + } + + // Use binary mode to obtain consistent positions. + // + ifdstream is (move (pr.in_ofd), + fdstream_mode::binary | fdstream_mode::skip); + + parser p; + unit tu (p.parse (is, *sp)); + + is.close (); + + if (pr.wait ()) + { + if (ps) + psrc.active = true; // Re-arm. + + unit_type& ut (tu.type); + module_info& mi (tu.module_info); + + if (!modules) + { + if (ut != unit_type::non_modular || !mi.imports.empty ()) + fail << "modules support required by " << src; + } + else + { + // Sanity checks. + // + // If we are compiling a module interface, make sure the + // translation unit has the necessary declarations. + // + if (ut != unit_type::module_iface && src.is_a (*x_mod)) + fail << src << " is not a module interface unit"; + + // A header unit should look like a non-modular translation unit. + // + if (md.type == unit_type::module_header) + { + if (ut != unit_type::non_modular) + fail << "module declaration in header unit " << src; + + ut = md.type; + mi.name = src.path ().string (); + } + + // Prior to 15.5 (19.12) VC was not using the 'export module M;' + // syntax so we use the preprequisite type to distinguish + // between interface and implementation units. + // + if (ctype == compiler_type::msvc && cmaj == 19 && cmin <= 11) + { + if (ut == unit_type::module_impl && src.is_a (*x_mod)) + ut = unit_type::module_iface; + } + } + + // If we were forced to reprocess, assume the checksum is not + // accurate (parts of the translation unit could have been + // #ifdef'ed out; see __build2_preprocess). + // + return pair<unit, string> ( + move (tu), + reprocess ? string () : move (p.checksum)); + } + + // Fall through. + } + catch (const io_error& e) + { + if (pr.wait ()) + fail << "unable to read " << x_lang << " preprocessor output: " + << e; + + // Fall through. + } + + assert (pr.exit && !*pr.exit); + const process_exit& e (*pr.exit); + + // What should we do with a normal error exit? Remember we suppressed + // the compiler's diagnostics. We used to issue a warning and continue + // with the assumption that the compilation step will fail with + // diagnostics. The problem with this approach is that we may fail + // before that because the information we return (e.g., module name) + // is bogus. So looks like failing is the only option. + // + if (e.normal ()) + { + fail << "unable to preprocess " << src << + info << "re-run with -s -V to display failing command" << + info << "then run failing command to display compiler diagnostics"; + } + else + run_finish (args, pr); // Throws. + } + catch (const process_error& e) + { + error << "unable to execute " << args[0] << ": " << e; + + if (e.child) + exit (1); + } + + throw failed (); + } + + // Extract and inject module dependencies. + // + void compile_rule:: + extract_modules (action a, + const scope& bs, + file& t, + linfo li, + const compile_target_types& tts, + const file& src, + match_data& md, + module_info&& mi, + depdb& dd, + bool& update) const + { + tracer trace (x, "compile_rule::extract_modules"); + + // If things go wrong, give the user a bit extra context. + // + auto df = make_diag_frame ( + [&src](const diag_record& dr) + { + if (verb != 0) + dr << info << "while extracting module dependencies from " << src; + }); + + unit_type ut (md.type); + module_imports& is (mi.imports); + + // Search and match all the modules we depend on. If this is a module + // implementation unit, then treat the module itself as if it was + // imported (we insert it first since for some compilers we have to + // differentiate between this special module and real imports). Note: + // move. + // + if (ut == unit_type::module_impl) + is.insert ( + is.begin (), + module_import {unit_type::module_iface, move (mi.name), false, 0}); + + // The change to the set of imports would have required a change to + // source code (or options). Changes to the bmi{}s themselves will be + // detected via the normal prerequisite machinery. However, the same set + // of imports could be resolved to a different set of bmi{}s (in a sense + // similar to changing the source file). To detect this we calculate and + // store a hash of all (not just direct) bmi{}'s paths. + // + sha256 cs; + + if (!is.empty ()) + md.modules = search_modules (a, bs, t, li, tts.bmi, src, is, cs); + + if (dd.expect (cs.string ()) != nullptr) + update = true; + + // Save the module map for compilers that use it. + // + switch (ctype) + { + case compiler_type::gcc: + { + // We don't need to redo this if the above hash hasn't changed and + // the database is still valid. + // + if (dd.writing () || !dd.skip ()) + { + auto write = [&dd] (const string& name, const path& file, bool q) + { + dd.write ("@ ", false); + if (q) dd.write ('\'', false); + dd.write (name, false); + if (q) dd.write ('\'', false); + dd.write (' ', false); + dd.write (file); + }; + + // The output mapping is provided in the same way as input. + // + if (ut == unit_type::module_iface || + ut == unit_type::module_header) + write (mi.name, t.path (), ut == unit_type::module_header); + + if (size_t start = md.modules.start) + { + // Note that we map both direct and indirect imports to override + // any module paths that might be stored in the BMIs (or + // resolved relative to "repository path", whatever that is). + // + const auto& pts (t.prerequisite_targets[a]); + for (size_t i (start); i != pts.size (); ++i) + { + if (const target* m = pts[i]) + { + // Save a variable lookup by getting the module name from + // the import list (see search_modules()). + // + // Note: all real modules (not header units). + // + write (is[i - start].name, m->as<file> ().path (), false); + } + } + } + } + break; + } + default: + break; + } + + // Set the cc.module_name rule-specific variable if this is an interface + // unit. Note that it may seem like a good idea to set it on the bmi{} + // group to avoid duplication. We, however, cannot do it MT-safely since + // we don't match the group. + // + // @@ MODHDR TODO: do we need this for header units? Currently we don't + // see header units here. + // + if (ut == unit_type::module_iface /*|| ut == unit_type::module_header*/) + { + if (value& v = t.state[a].assign (c_module_name)) + assert (cast<string> (v) == mi.name); + else + v = move (mi.name); // Note: move. + } + } + + inline bool + std_module (const string& m) + { + size_t n (m.size ()); + return (n >= 3 && + m[0] == 's' && m[1] == 't' && m[2] == 'd' && + (n == 3 || m[3] == '.')); + }; + + // Resolve imported modules to bmi*{} targets. + // + module_positions compile_rule:: + search_modules (action a, + const scope& bs, + file& t, + linfo li, + const target_type& btt, + const file& src, + module_imports& imports, + sha256& cs) const + { + tracer trace (x, "compile_rule::search_modules"); + + // NOTE: currently we don't see header unit imports (they are + // handled by extract_headers() and are not in imports). + + // So we have a list of imports and a list of "potential" module + // prerequisites. They are potential in the sense that they may or may + // not be required by this translation unit. In other words, they are + // the pool where we can resolve actual imports. + // + // Because we may not need all of these prerequisites, we cannot just go + // ahead and match all of them (and they can even have cycles; see rule + // synthesis). This poses a bit of a problem: the only way to discover + // the module's actual name (see cc.module_name) is by matching it. + // + // One way to solve this would be to make the user specify the module + // name for each mxx{} explicitly. This will be a major pain, however. + // Another would be to require encoding of the module name in the + // interface unit file name. For example, hello.core -> hello-core.mxx. + // This is better but still too restrictive: some will want to call it + // hello_core.mxx or HelloCore.mxx (because that's their file naming + // convention) or place it in a subdirectory, say, hello/core.mxx. + // + // In the above examples one common theme about all the file names is + // that they contain, in one form or another, the "tail" of the module + // name ('core'). So what we are going to do is require that the + // interface file names contain enough of the module name tail to + // unambiguously resolve all the module imports. On our side we are + // going to implement a "fuzzy" module name to file name match. This + // should be reliable enough since we will always verify our guesses + // once we match the target and extract the actual module name. Plus, + // the user will always have the option of resolving any impasses by + // specifying the module name explicitly. + // + // So, the fuzzy match: the idea is that each match gets a score, the + // number of characters in the module name that got matched. A match + // with the highest score is used. And we use the (length + 1) for a + // match against an actual module name. + // + // Actually, the scoring system is a bit more elaborate than that. + // Consider module name core.window and two files, window.mxx and + // abstract-window.mxx: which one is likely to define this module? + // Clearly the first, but in the above-described scheme they will get + // the same score. More generally, consider these "obvious" (to the + // human) situations: + // + // window.mxx vs abstract-window.mxx + // details/window.mxx vs abstract-window.mxx + // gtk-window.mxx vs gtk-abstract-window.mxx + // + // To handle such cases we are going to combine the above primary score + // with the following secondary scores (in that order): + // + // a) Strength of separation between matched and unmatched parts: + // + // '\0' > directory separator > other separator > unseparated + // + // Here '\0' signifies nothing to separate (unmatched part is empty). + // + // b) Shortness of the unmatched part. + // + // For std.* modules we only accept non-fuzzy matches (think std.core vs + // some core.mxx). And if such a module is unresolved, then we assume it + // is pre-built and will be found by some other means (e.g., VC's + // IFCPATH). + // + auto match_max = [] (const string& m) -> size_t + { + // The primary and sub-scores are packed in the following decimal + // representation: + // + // PPPPABBBB + // + // We use decimal instead of binary packing to make it easier to + // separate fields in the trace messages, during debugging, etc. + // + return m.size () * 100000 + 99999; // Maximum match score. + }; + + auto match = [] (const string& f, const string& m) -> size_t + { + auto file_sep = [] (char c) -> char + { + // Return the character (translating directory seperator to '/') if + // it is a separator and '\0' otherwise (so can be used as bool). + // + return (c == '_' || c == '-' || c == '.' ? c : + path::traits_type::is_separator (c) ? '/' : '\0'); + }; + + auto case_sep = [] (char c1, char c2) + { + return (alpha (c1) && + alpha (c2) && + (ucase (c1) == c1) != (ucase (c2) == c2)); + }; + + size_t fn (f.size ()), fi (fn); + size_t mn (m.size ()), mi (mn); + + // True if the previous character was counted as a real (that is, + // non-case changing) separator. + // + bool fsep (false); + bool msep (false); + + // Scan backwards for as long as we match. Keep track of the previous + // character for case change detection. + // + for (char fc, mc, fp ('\0'), mp ('\0'); + fi != 0 && mi != 0; + fp = fc, mp = mc, --fi, --mi) + { + fc = f[fi - 1]; + mc = m[mi - 1]; + + if (casecmp (fc, mc) == 0) + { + fsep = msep = false; + continue; + } + + // We consider all separators equal and character case change being + // a separators. Some examples of the latter: + // + // foo.bar + // fooBAR + // FOObar + // + bool fs (file_sep (fc)); + bool ms (mc == '_' || mc == '.'); + + if (fs && ms) + { + fsep = msep = true; + continue; + } + + // Only if one is a real separator do we consider case change. + // + if (fs || ms) + { + bool fa (false), ma (false); + if ((fs || (fa = case_sep (fp, fc))) && + (ms || (ma = case_sep (mp, mc)))) + { + // Stay on this character if imaginary punctuation (note: cannot + // be both true). + // + if (fa) {++fi; msep = true;} + if (ma) {++mi; fsep = true;} + + continue; + } + } + + break; // No match. + } + + // "Uncount" real separators. + // + if (fsep) fi++; + if (msep) mi++; + + // Use the number of characters matched in the module name and not + // in the file (this may not be the same because of the imaginary + // separators). + // + size_t ps (mn - mi); + + // The strength of separation sub-score. + // + // Check for case change between the last character that matched and + // the first character that did not. + // + size_t as (0); + if (fi == 0) as = 9; + else if (char c = file_sep (f[fi - 1])) as = c == '/' ? 8 : 7; + else if (fi != fn && case_sep (f[fi], f[fi - 1])) as = 7; + + // The length of the unmatched part sub-score. + // + size_t bs (9999 - fi); + + return ps * 100000 + as * 10000 + bs; + }; + + auto& pts (t.prerequisite_targets[a]); + size_t start (pts.size ()); // Index of the first to be added. + + // We have two parallel vectors: module names/scores in imports and + // targets in prerequisite_targets (offset with start). Pre-allocate + // NULL entries in the latter. + // + size_t n (imports.size ()); + pts.resize (start + n, nullptr); + + // Oh, yes, there is one "minor" complication. It's the last one, I + // promise. It has to do with module re-exporting (export import M;). + // In this case (currently) all implementations simply treat it as a + // shallow (from the BMI's point of view) reference to the module (or an + // implicit import, if you will). Do you see where it's going? Nowever + // good, that's right. This shallow reference means that the compiler + // should be able to find BMIs for all the re-exported modules, + // recursive. The good news is we are actually in a pretty good shape to + // handle this: after match all our prerequisite BMIs will have their + // prerequisite BMIs known, recursively. The only bit that is missing is + // the re-export flag of some sorts. As well as deciding where to handle + // it: here or in append_modules(). After some meditation it became + // clear handling it here will be simpler: we need to weed out + // duplicates for which we can re-use the imports vector. And we may + // also need to save this "flattened" list of modules in depdb. + // + // Ok, so, here is the plan: + // + // 1. There is no good place in prerequisite_targets to store the + // exported flag (no, using the marking facility across match/execute + // is a bad idea). So what we are going to do is put re-exported + // bmi{}s at the back and store (in the target's data pad) the start + // position. One bad aspect about this part is that we assume those + // bmi{}s have been matched by the same rule. But let's not kid + // ourselves, there will be no other rule that matches bmi{}s. + // + // 2. Once we have matched all the bmi{}s we are importing directly + // (with all the re-exported by us at the back), we will go over them + // and copy all of their re-exported bmi{}s (using the position we + // saved on step #1). The end result will be a recursively-explored + // list of imported bmi{}s that append_modules() can simply convert + // to the list of options. + // + // One issue with this approach is that these copied targets will be + // executed which means we need to adjust their dependent counts + // (which is normally done by match). While this seems conceptually + // correct (especially if you view re-exports as implicit imports), + // it's just extra overhead (we know they will be updated). So what + // we are going to do is save another position, that of the start of + // these copied-over targets, and will only execute up to this point. + // + // And after implementing this came the reality check: all the current + // implementations require access to all the imported BMIs, not only + // re-exported. Some (like Clang) store references to imported BMI files + // so we actually don't need to pass any extra options (unless things + // get moved) but they still need access to the BMIs (and things will + // most likely have to be done differenly for distributed compilation). + // + // So the revised plan: on the off chance that some implementation will + // do it differently we will continue maintaing the imported/re-exported + // split and how much to copy-over can be made compiler specific. + // + // As a first sub-step of step #1, move all the re-exported imports to + // the end of the vector. This will make sure they end up at the end + // of prerequisite_targets. Note: the special first import, if any, + // should be unaffected. + // + sort (imports.begin (), imports.end (), + [] (const module_import& x, const module_import& y) + { + return !x.exported && y.exported; + }); + + // Go over the prerequisites once. + // + // For (direct) library prerequisites, check their prerequisite bmi{}s + // (which should be searched and matched with module names discovered; + // see the library meta-information protocol for details). + // + // For our own bmi{} prerequisites, checking if each (better) matches + // any of the imports. + + // For fuzzy check if a file name (better) resolves any of our imports + // and if so make it the new selection. For exact the name is the actual + // module name and it can only resolve one import (there are no + // duplicates). + // + // Set done to true if all the imports have now been resolved to actual + // module names (which means we can stop searching). This will happens + // if all the modules come from libraries. Which will be fairly common + // (think of all the tests) so it's worth optimizing for. + // + bool done (false); + + auto check_fuzzy = [&trace, &imports, &pts, &match, &match_max, start, n] + (const target* pt, const string& name) + { + for (size_t i (0); i != n; ++i) + { + module_import& m (imports[i]); + + if (std_module (m.name)) // No fuzzy std.* matches. + continue; + + if (m.score > match_max (m.name)) // Resolved to module name. + continue; + + size_t s (match (name, m.name)); + + l5 ([&]{trace << name << " ~ " << m.name << ": " << s;}); + + if (s > m.score) + { + pts[start + i] = pt; + m.score = s; + } + } + }; + + // If resolved, return the "slot" in pts (we don't want to create a + // side build until we know we match; see below for details). + // + auto check_exact = [&trace, &imports, &pts, &match_max, start, n, &done] + (const string& name) -> const target** + { + const target** r (nullptr); + done = true; + + for (size_t i (0); i != n; ++i) + { + module_import& m (imports[i]); + + size_t ms (match_max (m.name)); + + if (m.score > ms) // Resolved to module name (no effect on done). + continue; + + if (r == nullptr) + { + size_t s (name == m.name ? ms + 1 : 0); + + l5 ([&]{trace << name << " ~ " << m.name << ": " << s;}); + + if (s > m.score) + { + r = &pts[start + i].target; + m.score = s; + continue; // Scan the rest to detect if all done. + } + } + + done = false; + } + + return r; + }; + + for (prerequisite_member p: group_prerequisite_members (a, t)) + { + if (include (a, t, p) != include_type::normal) // Excluded/ad hoc. + continue; + + const target* pt (p.load ()); // Should be cached for libraries. + + if (pt != nullptr) + { + const target* lt (nullptr); + + if (const libx* l = pt->is_a<libx> ()) + lt = link_member (*l, a, li); + else if (pt->is_a<liba> () || pt->is_a<libs> () || pt->is_a<libux> ()) + lt = pt; + + // If this is a library, check its bmi{}s and mxx{}s. + // + if (lt != nullptr) + { + for (const target* bt: lt->prerequisite_targets[a]) + { + if (bt == nullptr) + continue; + + // Note that here we (try) to use whatever flavor of bmi*{} is + // available. + // + // @@ MOD: BMI compatibility check. + // @@ UTL: we need to (recursively) see through libu*{} (and + // also in pkgconfig_save()). + // + if (bt->is_a<bmix> ()) + { + const string& n ( + cast<string> (bt->state[a].vars[c_module_name])); + + if (const target** p = check_exact (n)) + *p = bt; + } + else if (bt->is_a (*x_mod)) + { + // This is an installed library with a list of module sources + // (the source are specified as prerequisites but the fallback + // file rule puts them into prerequisite_targets for us). + // + // The module names should be specified but if not assume + // something else is going on and ignore. + // + const string* n (cast_null<string> (bt->vars[c_module_name])); + + if (n == nullptr) + continue; + + if (const target** p = check_exact (*n)) + *p = &make_module_sidebuild (a, bs, *lt, *bt, *n); + } + else + continue; + + if (done) + break; + } + + if (done) + break; + + continue; + } + + // Fall through. + } + + // While it would have been even better not to search for a target, we + // need to get hold of the corresponding mxx{} (unlikely but possible + // for bmi{} to have a different name). + // + // While we want to use group_prerequisite_members() below, we cannot + // call resolve_group() since we will be doing it "speculatively" for + // modules that we may use but also for modules that may use us. This + // quickly leads to deadlocks. So instead we are going to perform an + // ad hoc group resolution. + // + const target* pg; + if (p.is_a<bmi> ()) + { + pg = pt != nullptr ? pt : &p.search (t); + pt = &search (t, btt, p.key ()); // Same logic as in picking obj*{}. + } + else if (p.is_a (btt)) + { + pg = &search (t, bmi::static_type, p.key ()); + if (pt == nullptr) pt = &p.search (t); + } + else + continue; + + // Find the mxx{} prerequisite and extract its "file name" for the + // fuzzy match unless the user specified the module name explicitly. + // + for (prerequisite_member p: + prerequisite_members (a, t, group_prerequisites (*pt, pg))) + { + if (include (a, t, p) != include_type::normal) // Excluded/ad hoc. + continue; + + if (p.is_a (*x_mod)) + { + // Check for an explicit module name. Only look for an existing + // target (which means the name can only be specified on the + // target itself, not target type/pattern-spec). + // + const target* t (p.search_existing ()); + const string* n (t != nullptr + ? cast_null<string> (t->vars[c_module_name]) + : nullptr); + if (n != nullptr) + { + if (const target** p = check_exact (*n)) + *p = pt; + } + else + { + // Fuzzy match. + // + string f; + + // Add the directory part if it is relative. The idea is to + // include it into the module match, say hello.core vs + // hello/mxx{core}. + // + // @@ MOD: Why not for absolute? Good question. What if it + // contains special components, say, ../mxx{core}? + // + const dir_path& d (p.dir ()); + + if (!d.empty () && d.relative ()) + f = d.representation (); // Includes trailing slash. + + f += p.name (); + check_fuzzy (pt, f); + } + break; + } + } + + if (done) + break; + } + + // Diagnose unresolved modules. + // + if (!done) + { + for (size_t i (0); i != n; ++i) + { + if (pts[start + i] == nullptr && !std_module (imports[i].name)) + { + // It would have been nice to print the location of the import + // declaration. And we could save it during parsing at the expense + // of a few paths (that can be pooled). The question is what to do + // when we re-create this information from depdb? We could have + // saved the location information there but the relative paths + // (e.g., from the #line directives) could end up being wrong if + // the we re-run from a different working directory. + // + // It seems the only workable approach is to extract full location + // info during parse, not save it in depdb, when re-creating, + // fallback to just src path without any line/column information. + // This will probably cover the majority of case (most of the time + // it will be a misspelled module name, not a removal of module + // from buildfile). + // + // But at this stage this doesn't seem worth the trouble. + // + fail (relative (src)) << "unable to resolve module " + << imports[i].name; + } + } + } + + // Match in parallel and wait for completion. + // + match_members (a, t, pts, start); + + // Post-process the list of our (direct) imports. While at it, calculate + // the checksum of all (direct and indirect) bmi{} paths. + // + size_t exported (n); + size_t copied (pts.size ()); + + for (size_t i (0); i != n; ++i) + { + const module_import& m (imports[i]); + + // Determine the position of the first re-exported bmi{}. + // + if (m.exported && exported == n) + exported = i; + + const target* bt (pts[start + i]); + + if (bt == nullptr) + continue; // Unresolved (std.*). + + // Verify our guesses against extracted module names but don't waste + // time if it was a match against the actual module name. + // + const string& in (m.name); + + if (m.score <= match_max (in)) + { + const string& mn (cast<string> (bt->state[a].vars[c_module_name])); + + if (in != mn) + { + // Note: matched, so the group should be resolved. + // + for (prerequisite_member p: group_prerequisite_members (a, *bt)) + { + if (include (a, t, p) != include_type::normal) // Excluded/ad hoc. + continue; + + if (p.is_a (*x_mod)) // Got to be there. + { + fail (relative (src)) + << "failed to correctly guess module name from " << p << + info << "guessed: " << in << + info << "actual: " << mn << + info << "consider adjusting module interface file names or" << + info << "consider specifying module name with " << x + << ".module_name"; + } + } + } + } + + // Hash (we know it's a file). + // + cs.append (static_cast<const file&> (*bt).path ().string ()); + + // Copy over bmi{}s from our prerequisites weeding out duplicates. + // + if (size_t j = bt->data<match_data> ().modules.start) + { + // Hard to say whether we should reserve or not. We will probably + // get quite a bit of duplications. + // + auto& bpts (bt->prerequisite_targets[a]); + for (size_t m (bpts.size ()); j != m; ++j) + { + const target* et (bpts[j]); + + if (et == nullptr) + continue; // Unresolved (std.*). + + const string& mn (cast<string> (et->state[a].vars[c_module_name])); + + if (find_if (imports.begin (), imports.end (), + [&mn] (const module_import& i) + { + return i.name == mn; + }) == imports.end ()) + { + pts.push_back (et); + cs.append (static_cast<const file&> (*et).path ().string ()); + + // Add to the list of imports for further duplicate suppression. + // We could have stored reference to the name (e.g., in score) + // but it's probably not worth it if we have a small string + // optimization. + // + imports.push_back ( + module_import {unit_type::module_iface, mn, true, 0}); + } + } + } + } + + if (copied == pts.size ()) // No copied tail. + copied = 0; + + if (exported == n) // No (own) re-exported imports. + exported = copied; + else + exported += start; // Rebase. + + return module_positions {start, exported, copied}; + } + + // Find or create a modules sidebuild subproject returning its root + // directory. + // + dir_path compile_rule:: + find_modules_sidebuild (const scope& rs) const + { + // First figure out where we are going to build. We want to avoid + // multiple sidebuilds so the outermost scope that has loaded the + // cc.config module and that is within our amalgmantion seems like a + // good place. + // + const scope* as (&rs); + { + const scope* ws (as->weak_scope ()); + if (as != ws) + { + const scope* s (as); + do + { + s = s->parent_scope ()->root_scope (); + + // Use cc.core.vars as a proxy for {c,cxx}.config (a bit smelly). + // + // This is also the module that registers the scope operation + // callback that cleans up the subproject. + // + if (cast_false<bool> ((*s)["cc.core.vars.loaded"])) + as = s; + + } while (s != ws); + } + } + + // We build modules in a subproject (since there might be no full + // language support loaded in the amalgamation, only *.config). So the + // first step is to check if the project has already been created and/or + // loaded and if not, then to go ahead and do so. + // + dir_path pd (as->out_path () / + as->root_extra->build_dir / + modules_sidebuild_dir /= + x); + + const scope* ps (&rs.ctx.scopes.find (pd)); + + if (ps->out_path () != pd) + { + // Switch the phase to load then create and load the subproject. + // + phase_switch phs (rs.ctx, run_phase::load); + + // Re-test again now that we are in exclusive phase (another thread + // could have already created and loaded the subproject). + // + ps = &rs.ctx.scopes.find (pd); + + if (ps->out_path () != pd) + { + // The project might already be created in which case we just need + // to load it. + // + optional<bool> altn (false); // Standard naming scheme. + if (!is_src_root (pd, altn)) + { + // Copy our standard and force modules. + // + string extra; + + if (const string* std = cast_null<string> (rs[x_std])) + extra += string (x) + ".std = " + *std + '\n'; + + extra += string (x) + ".features.modules = true"; + + config::create_project ( + pd, + as->out_path ().relative (pd), /* amalgamation */ + {}, /* boot_modules */ + extra, /* root_pre */ + {string (x) + '.'}, /* root_modules */ + "", /* root_post */ + false, /* config */ + false, /* buildfile */ + "the cc module", + 2); /* verbosity */ + } + + ps = &load_project (as->rw () /* lock */, + pd, + pd, + false /* forwarded */); + } + } + + // Some sanity checks. + // +#ifndef NDEBUG + assert (ps->root ()); + const module* m (ps->lookup_module<module> (x)); + assert (m != nullptr && m->modules); +#endif + + return pd; + } + + // Synthesize a dependency for building a module binary interface on + // the side. + // + const file& compile_rule:: + make_module_sidebuild (action a, + const scope& bs, + const target& lt, + const target& mt, + const string& mn) const + { + tracer trace (x, "compile_rule::make_module_sidebuild"); + + // Note: see also make_header_sidebuild() below. + + dir_path pd (find_modules_sidebuild (*bs.root_scope ())); + + // We need to come up with a file/target name that will be unique enough + // not to conflict with other modules. If we assume that within an + // amalgamation there is only one "version" of each module, then the + // module name itself seems like a good fit. We just replace '.' with + // '-'. + // + string mf; + transform (mn.begin (), mn.end (), + back_inserter (mf), + [] (char c) {return c == '.' ? '-' : c;}); + + // It seems natural to build a BMI type that corresponds to the library + // type. After all, this is where the object file part of the BMI is + // going to come from (though things will probably be different for + // module-only libraries). + // + const target_type& tt (compile_types (link_type (lt).type).bmi); + + // Store the BMI target in the subproject root. If the target already + // exists then we assume all this is already done (otherwise why would + // someone have created such a target). + // + if (const file* bt = bs.ctx.targets.find<file> ( + tt, + pd, + dir_path (), // Always in the out tree. + mf, + nullopt, // Use default extension. + trace)) + return *bt; + + prerequisites ps; + ps.push_back (prerequisite (mt)); + + // We've added the mxx{} but it may import other modules from this + // library. Or from (direct) dependencies of this library. We add them + // all as prerequisites so that the standard module search logic can + // sort things out. This is pretty similar to what we do in link when + // synthesizing dependencies for bmi{}'s. + // + // Note: lt is matched and so the group is resolved. + // + ps.push_back (prerequisite (lt)); + for (prerequisite_member p: group_prerequisite_members (a, lt)) + { + if (include (a, lt, p) != include_type::normal) // Excluded/ad hoc. + continue; + + // @@ TODO: will probably need revision if using sidebuild for + // non-installed libraries (e.g., direct BMI dependencies + // will probably have to be translated to mxx{} or some such). + // + if (p.is_a<libx> () || + p.is_a<liba> () || p.is_a<libs> () || p.is_a<libux> ()) + { + ps.push_back (p.as_prerequisite ()); + } + } + + auto p (bs.ctx.targets.insert_locked ( + tt, + move (pd), + dir_path (), // Always in the out tree. + move (mf), + nullopt, // Use default extension. + true, // Implied. + trace)); + file& bt (static_cast<file&> (p.first)); + + // Note that this is racy and someone might have created this target + // while we were preparing the prerequisite list. + // + if (p.second.owns_lock ()) + bt.prerequisites (move (ps)); + + return bt; + } + + // Synthesize a dependency for building a header unit binary interface on + // the side. + // + const file& compile_rule:: + make_header_sidebuild (action, + const scope& bs, + linfo li, + const file& ht) const + { + tracer trace (x, "compile_rule::make_header_sidebuild"); + + // Note: similar to make_module_sidebuild() above. + + dir_path pd (find_modules_sidebuild (*bs.root_scope ())); + + // What should we use as a file/target name? On one hand we want it + // unique enough so that <stdio.h> and <custom/stdio.h> don't end up + // with the same BMI. On the other, we need the same headers resolving + // to the same target, regardless of how they were imported. So it feels + // like the name should be the absolute and normalized (actualized on + // case-insensitive filesystems) header path. We could try to come up + // with something by sanitizing certain characters, etc. But then the + // names will be very long and ugly, they will run into path length + // limits, etc. So instead we will use the file name plus an abbreviated + // hash of the whole path, something like stdio-211321fe6de7. + // + string mf; + { + // @@ MODHDR: Can we assume the path is actualized since the header + // target came from enter_header()? No, not anymore: it + // is now normally just normalized. + // + const path& hp (ht.path ()); + mf = hp.leaf ().make_base ().string (); + mf += '-'; + mf += sha256 (hp.string ()).abbreviated_string (12); + } + + const target_type& tt (compile_types (li.type).hbmi); + + if (const file* bt = bs.ctx.targets.find<file> ( + tt, + pd, + dir_path (), // Always in the out tree. + mf, + nullopt, // Use default extension. + trace)) + return *bt; + + prerequisites ps; + ps.push_back (prerequisite (ht)); + + auto p (bs.ctx.targets.insert_locked ( + tt, + move (pd), + dir_path (), // Always in the out tree. + move (mf), + nullopt, // Use default extension. + true, // Implied. + trace)); + file& bt (static_cast<file&> (p.first)); + + // Note that this is racy and someone might have created this target + // while we were preparing the prerequisite list. + // + if (p.second.owns_lock ()) + bt.prerequisites (move (ps)); + + return bt; + } + + // Filter cl.exe noise (msvc.cxx). + // + void + msvc_filter_cl (ifdstream&, const path& src); + + // Append header unit-related options. + // + // Note that this function is called for both full preprocessing and + // compilation proper and in the latter case it is followed by a call + // to append_modules(). + // + void compile_rule:: + append_headers (environment&, + cstrings& args, + small_vector<string, 2>& stor, + action, + const file&, + const match_data& md, + const path& dd) const + { + switch (ctype) + { + case compiler_type::gcc: + { + if (md.headers != 0) + { + string s (relative (dd).string ()); + s.insert (0, "-fmodule-mapper="); + s += "?@"; // Cookie (aka line prefix). + stor.push_back (move (s)); + } + + break; + } + case compiler_type::clang: + case compiler_type::msvc: + case compiler_type::icc: + break; + } + + // Shallow-copy storage to args. Why not do it as we go along pushing + // into storage? Because of potential reallocations. + // + for (const string& a: stor) + args.push_back (a.c_str ()); + } + + // Append module-related options. + // + // Note that this function is only called for the compilation proper and + // after a call to append_headers() (so watch out for duplicate options). + // + void compile_rule:: + append_modules (environment& env, + cstrings& args, + small_vector<string, 2>& stor, + action a, + const file& t, + const match_data& md, + const path& dd) const + { + unit_type ut (md.type); + const module_positions& ms (md.modules); + + dir_path stdifc; // See the VC case below. + + switch (ctype) + { + case compiler_type::gcc: + { + // Use the module map stored in depdb. + // + // Note that it is also used to specify the output BMI file. + // + if (md.headers == 0 && // Done in append_headers()? + (ms.start != 0 || + ut == unit_type::module_iface || + ut == unit_type::module_header)) + { + string s (relative (dd).string ()); + s.insert (0, "-fmodule-mapper="); + s += "?@"; // Cookie (aka line prefix). + stor.push_back (move (s)); + } + + break; + } + case compiler_type::clang: + { + if (ms.start == 0) + return; + + // Clang embeds module file references so we only need to specify + // our direct imports. + // + // If/when we get the ability to specify the mapping in a file, we + // will pass the whole list. + // +#if 0 + // In Clang the module implementation's unit .pcm is special and + // must be "loaded". + // + if (ut == unit_type::module_impl) + { + const file& f (pts[ms.start]->as<file> ()); + string s (relative (f.path ()).string ()); + s.insert (0, "-fmodule-file="); + stor.push_back (move (s)); + } + + // Use the module map stored in depdb for others. + // + string s (relative (dd).string ()); + s.insert (0, "-fmodule-file-map=@="); + stor.push_back (move (s)); +#else + auto& pts (t.prerequisite_targets[a]); + for (size_t i (ms.start), + n (ms.copied != 0 ? ms.copied : pts.size ()); + i != n; + ++i) + { + const target* pt (pts[i]); + + if (pt == nullptr) + continue; + + // Here we use whatever bmi type has been added. And we know all + // of these are bmi's. + // + const file& f (pt->as<file> ()); + string s (relative (f.path ()).string ()); + + // In Clang the module implementation's unit .pcm is special and + // must be "loaded". + // + if (ut == unit_type::module_impl && i == ms.start) + s.insert (0, "-fmodule-file="); + else + { + s.insert (0, 1, '='); + s.insert (0, cast<string> (f.state[a].vars[c_module_name])); + s.insert (0, "-fmodule-file="); + } + + stor.push_back (move (s)); + } +#endif + break; + } + case compiler_type::msvc: + { + if (ms.start == 0) + return; + + auto& pts (t.prerequisite_targets[a]); + for (size_t i (ms.start), n (pts.size ()); + i != n; + ++i) + { + const target* pt (pts[i]); + + if (pt == nullptr) + continue; + + // Here we use whatever bmi type has been added. And we know all + // of these are bmi's. + // + const file& f (pt->as<file> ()); + + // In VC std.* modules can only come from a single directory + // specified with the IFCPATH environment variable or the + // /module:stdIfcDir option. + // + if (std_module (cast<string> (f.state[a].vars[c_module_name]))) + { + dir_path d (f.path ().directory ()); + + if (stdifc.empty ()) + { + // Go one directory up since /module:stdIfcDir will look in + // either Release or Debug subdirectories. Keeping the result + // absolute feels right. + // + stor.push_back ("/module:stdIfcDir"); + stor.push_back (d.directory ().string ()); + stdifc = move (d); + } + else if (d != stdifc) // Absolute and normalized. + fail << "multiple std.* modules in different directories"; + } + else + { + stor.push_back ("/module:reference"); + stor.push_back (relative (f.path ()).string ()); + } + } + break; + } + case compiler_type::icc: + break; + } + + // Shallow-copy storage to args. Why not do it as we go along pushing + // into storage? Because of potential reallocations. + // + for (const string& a: stor) + args.push_back (a.c_str ()); + + // VC's IFCPATH takes precedence over /module:stdIfcDir so unset it + // if we are using our own std modules. + // + if (!stdifc.empty ()) + env.push_back ("IFCPATH"); + } + + target_state compile_rule:: + perform_update (action a, const target& xt) const + { + const file& t (xt.as<file> ()); + const path& tp (t.path ()); + + match_data md (move (t.data<match_data> ())); + unit_type ut (md.type); + + context& ctx (t.ctx); + + // While all our prerequisites are already up-to-date, we still have to + // execute them to keep the dependency counts straight. Actually, no, we + // may also have to update the modules. + // + // Note that this also takes care of forcing update on any ad hoc + // prerequisite change. + // + auto pr ( + execute_prerequisites<file> ( + md.src.type (), + a, t, + md.mt, + [s = md.modules.start] (const target&, size_t i) + { + return s != 0 && i >= s; // Only compare timestamps for modules. + }, + md.modules.copied)); // See search_modules() for details. + + const file& s (pr.second); + const path* sp (&s.path ()); + + if (pr.first) + { + if (md.touch) + { + touch (ctx, tp, false, 2); + t.mtime (system_clock::now ()); + ctx.skip_count.fetch_add (1, memory_order_relaxed); + } + // Note: else mtime should be cached. + + return *pr.first; + } + + // Make sure depdb is no older than any of our prerequisites (see md.mt + // logic description above for details). Also save the sequence start + // time if doing mtime checks (see the depdb::check_mtime() call below). + // + timestamp start (depdb::mtime_check () + ? system_clock::now () + : timestamp_unknown); + + touch (ctx, md.dd, false, verb_never); + + const scope& bs (t.base_scope ()); + const scope& rs (*bs.root_scope ()); + + otype ot (compile_type (t, ut)); + linfo li (link_info (bs, ot)); + compile_target_types tts (compile_types (ot)); + + environment env; + cstrings args {cpath.recall_string ()}; + + // If we are building a module interface, then the target is bmi*{} and + // its ad hoc member is obj*{}. For header units there is no obj*{}. + // + path relm; + path relo (ut == unit_type::module_header + ? path () + : relative (ut == unit_type::module_iface + ? find_adhoc_member<file> (t, tts.obj)->path () + : tp)); + + // Build the command line. + // + if (md.pp != preprocessed::all) + { + append_options (args, t, c_poptions); + append_options (args, t, x_poptions); + + // Add *.export.poptions from prerequisite libraries. + // + append_lib_options (bs, args, a, t, li); + + // Extra system header dirs (last). + // + assert (sys_inc_dirs_extra <= sys_inc_dirs.size ()); + append_option_values ( + args, "-I", + sys_inc_dirs.begin () + sys_inc_dirs_extra, sys_inc_dirs.end (), + [] (const dir_path& d) {return d.string ().c_str ();}); + + if (md.symexport) + append_symexport_options (args, t); + } + + append_options (args, t, c_coptions); + append_options (args, t, x_coptions); + append_options (args, tstd); + + string out, out1; // Output options storage. + small_vector<string, 2> header_args; // Header unit options storage. + small_vector<string, 2> module_args; // Module options storage. + + size_t out_i (0); // Index of the -o option. + size_t lang_n (0); // Number of lang options. + + if (cclass == compiler_class::msvc) + { + // The /F*: option variants with separate names only became available + // in VS2013/12.0. Why do we bother? Because the command line suddenly + // becomes readable. + // + uint64_t ver (cast<uint64_t> (rs[x_version_major])); + + args.push_back ("/nologo"); + + // While we want to keep the low-level build as "pure" as possible, + // the two misguided defaults, exceptions and runtime, just have to be + // fixed. Otherwise the default build is pretty much unusable. But we + // also make sure that the user can easily disable our defaults: if we + // see any relevant options explicitly specified, we take our hands + // off. + // + // For C looks like no /EH* (exceptions supported but no C++ objects + // destroyed) is a reasonable default. + // + if (x_lang == lang::cxx && !find_option_prefix ("/EH", args)) + args.push_back ("/EHsc"); + + // The runtime is a bit more interesting. At first it may seem like a + // good idea to be a bit clever and use the static runtime if we are + // building obja{}. And for obje{} we could decide which runtime to + // use based on the library link order: if it is static-only, then we + // could assume the static runtime. But it is indeed too clever: when + // building liba{} we have no idea who is going to use it. It could be + // an exe{} that links both static and shared libraries (and is + // therefore built with the shared runtime). And to safely use the + // static runtime, everything must be built with /MT and there should + // be no DLLs in the picture. So we are going to play it safe and + // always default to the shared runtime. + // + // In a similar vein, it would seem reasonable to use the debug runtime + // if we are compiling with debug. But, again, there will be fireworks + // if we have some projects built with debug and some without and then + // we try to link them together (which is not an unreasonable thing to + // do). So by default we will always use the release runtime. + // + if (!find_option_prefixes ({"/MD", "/MT"}, args)) + args.push_back ("/MD"); + + msvc_sanitize_cl (args); + + append_headers (env, args, header_args, a, t, md, md.dd); + append_modules (env, args, module_args, a, t, md, md.dd); + + // The presence of /Zi or /ZI causes the compiler to write debug info + // to the .pdb file. By default it is a shared file called vcNN.pdb + // (where NN is the VC version) created (wait for it) in the current + // working directory (and not the directory of the .obj file). Also, + // because it is shared, there is a special Windows service that + // serializes access. We, of course, want none of that so we will + // create a .pdb per object file. + // + // Note that this also changes the name of the .idb file (used for + // minimal rebuild and incremental compilation): cl.exe take the /Fd + // value and replaces the .pdb extension with .idb. + // + // Note also that what we are doing here appears to be incompatible + // with PCH (/Y* options) and /Gm (minimal rebuild). + // + if (find_options ({"/Zi", "/ZI"}, args)) + { + if (ver >= 18) + args.push_back ("/Fd:"); + else + out1 = "/Fd"; + + out1 += relo.string (); + out1 += ".pdb"; + + args.push_back (out1.c_str ()); + } + + if (ver >= 18) + { + args.push_back ("/Fo:"); + args.push_back (relo.string ().c_str ()); + } + else + { + out = "/Fo" + relo.string (); + args.push_back (out.c_str ()); + } + + // @@ MODHDR MSVC + // + if (ut == unit_type::module_iface) + { + relm = relative (tp); + + args.push_back ("/module:interface"); + args.push_back ("/module:output"); + args.push_back (relm.string ().c_str ()); + } + + // Note: no way to indicate that the source if already preprocessed. + + args.push_back ("/c"); // Compile only. + append_lang_options (args, md); // Compile as. + args.push_back (sp->string ().c_str ()); // Note: relied on being last. + } + else + { + if (ot == otype::s) + { + // On Darwin, Win32 -fPIC is the default. + // + if (tclass == "linux" || tclass == "bsd") + args.push_back ("-fPIC"); + } + + append_headers (env, args, header_args, a, t, md, md.dd); + append_modules (env, args, module_args, a, t, md, md.dd); + + // Note: the order of the following options is relied upon below. + // + out_i = args.size (); // Index of the -o option. + + if (ut == unit_type::module_iface || ut == unit_type::module_header) + { + switch (ctype) + { + case compiler_type::gcc: + { + // Output module file is specified in the mapping file, the + // same as input. + // + if (ut != unit_type::module_header) // No object file. + { + args.push_back ("-o"); + args.push_back (relo.string ().c_str ()); + args.push_back ("-c"); + } + break; + } + case compiler_type::clang: + { + relm = relative (tp); + + args.push_back ("-o"); + args.push_back (relm.string ().c_str ()); + args.push_back ("--precompile"); + + // Without this option Clang's .pcm will reference source files. + // In our case this file may be transient (.ii). Plus, it won't + // play nice with distributed compilation. + // + args.push_back ("-Xclang"); + args.push_back ("-fmodules-embed-all-files"); + + break; + } + case compiler_type::msvc: + case compiler_type::icc: + assert (false); + } + } + else + { + args.push_back ("-o"); + args.push_back (relo.string ().c_str ()); + args.push_back ("-c"); + } + + lang_n = append_lang_options (args, md); + + if (md.pp == preprocessed::all) + { + // Note that the mode we select must still handle comments and line + // continuations. So some more compiler-specific voodoo. + // + switch (ctype) + { + case compiler_type::gcc: + { + // -fdirectives-only is available since GCC 4.3.0. + // + if (cmaj > 4 || (cmaj == 4 && cmin >= 3)) + { + args.push_back ("-fpreprocessed"); + args.push_back ("-fdirectives-only"); + } + break; + } + case compiler_type::clang: + { + // Clang handles comments and line continuations in the + // preprocessed source (it does not have -fpreprocessed). + // + break; + } + case compiler_type::icc: + break; // Compile as normal source for now. + case compiler_type::msvc: + assert (false); + } + } + + args.push_back (sp->string ().c_str ()); + } + + args.push_back (nullptr); + + if (!env.empty ()) + env.push_back (nullptr); + + // With verbosity level 2 print the command line as if we are compiling + // the source file, not its preprocessed version (so that it's easy to + // copy and re-run, etc). Only at level 3 and above print the real deal. + // + if (verb == 1) + text << x_name << ' ' << s; + else if (verb == 2) + print_process (args); + + // If we have the (partially) preprocessed output, switch to that. + // + bool psrc (!md.psrc.path.empty ()); + bool pact (md.psrc.active); + if (psrc) + { + args.pop_back (); // nullptr + args.pop_back (); // sp + + sp = &md.psrc.path; + + // This should match with how we setup preprocessing. + // + switch (ctype) + { + case compiler_type::gcc: + { + // The -fpreprocessed is implied by .i/.ii. But not when compiling + // a header unit (there is no .hi/.hii). + // + if (ut == unit_type::module_header) + args.push_back ("-fpreprocessed"); + else + // Pop -x since it takes precedence over the extension. + // + // @@ I wonder why bother and not just add -fpreprocessed? Are + // we trying to save an option or does something break? + // + for (; lang_n != 0; --lang_n) + args.pop_back (); + + args.push_back ("-fdirectives-only"); + break; + } + case compiler_type::clang: + { + // Note that without -x Clang will treat .i/.ii as fully + // preprocessed. + // + break; + } + case compiler_type::msvc: + { + // Nothing to do (/TP or /TC already there). + // + break; + } + case compiler_type::icc: + assert (false); + } + + args.push_back (sp->string ().c_str ()); + args.push_back (nullptr); + + // Let's keep the preprocessed file in case of an error but only at + // verbosity level 3 and up (when one actually sees it mentioned on + // the command line). We also have to re-arm on success (see below). + // + if (pact && verb >= 3) + md.psrc.active = false; + } + + if (verb >= 3) + print_process (args); + + // @@ DRYRUN: Currently we discard the (partially) preprocessed file on + // dry-run which is a waste. Even if we keep the file around (like we do + // for the error case; see above), we currently have no support for + // re-using the previously preprocessed output. However, everything + // points towards us needing this in the near future since with modules + // we may be out of date but not needing to re-preprocess the + // translation unit (i.e., one of the imported module's has BMIs + // changed). + // + if (!ctx.dry_run) + { + try + { + // VC cl.exe sends diagnostics to stdout. It also prints the file + // name being compiled as the first line. So for cl.exe we redirect + // stdout to a pipe, filter that noise out, and send the rest to + // stderr. + // + // For other compilers redirect stdout to stderr, in case any of + // them tries to pull off something similar. For sane compilers this + // should be harmless. + // + bool filter (ctype == compiler_type::msvc); + + process pr (cpath, + args.data (), + 0, (filter ? -1 : 2), 2, + nullptr, // CWD + env.empty () ? nullptr : env.data ()); + + if (filter) + { + try + { + ifdstream is ( + move (pr.in_ofd), fdstream_mode::text, ifdstream::badbit); + + msvc_filter_cl (is, *sp); + + // If anything remains in the stream, send it all to stderr. + // Note that the eof check is important: if the stream is at + // eof, this and all subsequent writes to the diagnostics stream + // will fail (and you won't see a thing). + // + if (is.peek () != ifdstream::traits_type::eof ()) + diag_stream_lock () << is.rdbuf (); + + is.close (); + } + catch (const io_error&) {} // Assume exits with error. + } + + run_finish (args, pr); + } + catch (const process_error& e) + { + error << "unable to execute " << args[0] << ": " << e; + + if (e.child) + exit (1); + + throw failed (); + } + } + + // Remove preprocessed file (see above). + // + if (pact && verb >= 3) + md.psrc.active = true; + + // Clang's module compilation requires two separate compiler + // invocations. + // + if (ctype == compiler_type::clang && ut == unit_type::module_iface) + { + // Adjust the command line. First discard everything after -o then + // build the new "tail". + // + args.resize (out_i + 1); + args.push_back (relo.string ().c_str ()); // Produce .o. + args.push_back ("-c"); // By compiling .pcm. + args.push_back ("-Wno-unused-command-line-argument"); + args.push_back (relm.string ().c_str ()); + args.push_back (nullptr); + + if (verb >= 2) + print_process (args); + + if (!ctx.dry_run) + { + // Remove the target file if this fails. If we don't do that, we + // will end up with a broken build that is up-to-date. + // + auto_rmfile rm (relm); + + try + { + process pr (cpath, + args.data (), + 0, 2, 2, + nullptr, // CWD + env.empty () ? nullptr : env.data ()); + + run_finish (args, pr); + } + catch (const process_error& e) + { + error << "unable to execute " << args[0] << ": " << e; + + if (e.child) + exit (1); + + throw failed (); + } + + rm.cancel (); + } + } + + timestamp now (system_clock::now ()); + + if (!ctx.dry_run) + depdb::check_mtime (start, md.dd, tp, now); + + // Should we go to the filesystem and get the new mtime? We know the + // file has been modified, so instead just use the current clock time. + // It has the advantage of having the subseconds precision. Plus, in + // case of dry-run, the file won't be modified. + // + t.mtime (now); + return target_state::changed; + } + + target_state compile_rule:: + perform_clean (action a, const target& xt) const + { + const file& t (xt.as<file> ()); + + clean_extras extras; + + switch (ctype) + { + case compiler_type::gcc: extras = {".d", x_pext, ".t"}; break; + case compiler_type::clang: extras = {".d", x_pext}; break; + case compiler_type::msvc: extras = {".d", x_pext, ".idb", ".pdb"};break; + case compiler_type::icc: extras = {".d"}; break; + } + + return perform_clean_extra (a, t, extras); + } + } +} |