From d64ae97f6865bc25d496485622530e2a090c2eb4 Mon Sep 17 00:00:00 2001 From: Boris Kolpackov Date: Wed, 21 Aug 2019 12:11:48 +0200 Subject: Implement dynamic loading of build system modules --- libbuild2/module.cxx | 307 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 269 insertions(+), 38 deletions(-) (limited to 'libbuild2/module.cxx') diff --git a/libbuild2/module.cxx b/libbuild2/module.cxx index 50530f2..1feb121 100644 --- a/libbuild2/module.cxx +++ b/libbuild2/module.cxx @@ -4,23 +4,259 @@ #include +#ifndef _WIN32 +# include +#else +# include +#endif + +#include // import() #include #include #include +// Core modules bundled with libbuild2. +// +#include +#include +#include +#include + using namespace std; +using namespace butl; namespace build2 { - available_module_map builtin_modules; + loaded_module_map loaded_modules; + + // Sorted array of bundled modules (excluding core modules bundled with + // libbuild2; see below). + // + static const char* bundled_modules[] = { + "bash", + "in", + "version" + }; + + static inline bool + bundled_module (const string& mod) + { + return binary_search ( + bundled_modules, + bundled_modules + sizeof (bundled_modules) / sizeof (*bundled_modules), + mod); + } + + static module_load_function* + import_module (scope& /*bs*/, + const string& mod, + const location& loc, + bool boot, + bool opt) + { + // Take care of core modules that are bundled with libbuild2 in case they + // are not pre-loaded by the driver. + // + if (mod == "config") return &config::build2_config_load; + else if (mod == "dist") return &dist::build2_dist_load; + else if (mod == "install") return &install::build2_install_load; + else if (mod == "test") return &test::build2_test_load; + + bool bundled (bundled_module (mod)); + + // Importing external modules during bootstrap is problematic: we haven't + // loaded config.build nor entered all the variable overrides so it's not + // clear what import() can do except confuse matters. So this requires + // more thinking. + // + if (boot && !bundled) + { + fail (loc) << "unable to load build system module " << mod << + info << "loading external modules during bootstrap is not yet " + << "supported"; + } + + path lib; + +#if 0 + // See if we can import a target for this module. + // + // Check if one of the bundled modules, if so, the project name is + // build2, otherwise -- libbuild2-. + // + // The target we are looking for is %lib{build2-}. + // + name tgt ( + import (bs, + name (bundled ? "build2" : "libbuild2-" + mod, + dir_path (), + "lib", + "build2-" + mod), + loc)); + + if (!tgt.qualified ()) + { + // Switch the phase and update the target. This will also give us the + // shared library path. + // + // @@ TODO + // + } + else +#endif + { + // No luck. Form the shared library name (incorporating build system + // core version) and try using system-default search (installed, rpath, + // etc). + + // @@ This is unfortunate: it would have been nice to do something + // similar to what we've done for exe{}. While libs{} is in the bin + // module, we could bring it in (we've done it for exe{}). The + // problems are: it is intertwined with its group (lib{}) and we + // don't have any mechanisms to deal with prefixes, only extensions. + // + const char* pfx; + const char* sfx; +#if defined(_WIN32) + pfx = "build2-"; sfx = ".dll"; +#elif defined(__APPLE__) + pfx = "libbuild2-"; sfx = ".dylib"; +#else + pfx = "libbuild2-"; sfx = ".so"; +#endif + + lib = path (pfx + mod + '-' + build_version_interface + sfx); + } + + string sym (sanitize_identifier ("build2_" + mod + "_load")); + + // Note that we don't unload our modules since it's not clear what would + // the benefit be. + // + module_load_function* r (nullptr); + +#ifndef _WIN32 + // Use RTLD_NOW instead of RTLD_LAZY to both speed things up (we are going + // to use this module now) and to detect any symbol mismatches. + // + if (void* h = dlopen (lib.string ().c_str (), RTLD_NOW | RTLD_GLOBAL)) + { + r = function_cast (dlsym (h, sym.c_str ())); + + // I don't think we should ignore this even if optional. + // + if (r == nullptr) + fail (loc) << "unable to lookup " << sym << " in build system module " + << mod << " (" << lib << "): " << dlerror (); + } + else if (!opt) + fail (loc) << "unable to load build system module " << mod + << " (" << lib << "): " << dlerror (); +#else + if (HMODULE h = LoadLibrary (lib.string ().c_str ())) + { + r = function_cast ( + GetProcAddress (h, sym.c_str ())); + + if (r == nullptr) + fail (loc) << "unable to lookup " << sym << " in build system module " + << mod << " (" << lib << "): " << win32::last_error_msg (); + } + else if (!opt) + fail (loc) << "unable to load build system module " << mod + << " (" << lib << "): " << win32::last_error_msg (); +#endif + + return r; + } + + static const module_functions* + find_module (scope& bs, + const string& smod, + const location& loc, + bool boot, + bool opt) + { + // Optional modules and submodules sure make this logic convoluted. So we + // divide it into two parts: (1) find or insert an entry (for submodule + // or, failed that, for the main module, the latter potentially NULL) and + // (2) analyze the entry and issue diagnostics. + // + auto i (loaded_modules.find (smod)), e (loaded_modules.end ()); + + if (i == e) + { + // If this is a submodule, get the main module name. + // + string mmod (smod, 0, smod.find ('.')); + + if (mmod != smod) + i = loaded_modules.find (mmod); + + if (i == e) + { + module_load_function* f (import_module (bs, mmod, loc, boot, opt)); + + if (f != nullptr) + { + // Enter all the entries noticing which one is our submodule. If + // none are, then we notice the main module. + // + for (const module_functions* j (f ()); j->name != nullptr; ++j) + { + const string& n (j->name); + + auto p (loaded_modules.emplace (n, j)); + + if (!p.second) + fail (loc) << "build system submodule name " << n << " of main " + << "module " << mmod << " is already in use"; + + if (n == smod || (i == e && n == mmod)) + i = p.first; + } + + // We should at least have the main module. + // + if (i == e) + fail (loc) << "invalid function list in build system module " + << mmod; + } + else + i = loaded_modules.emplace (move (mmod), nullptr).first; + } + } + + // Now the iterator points to a submodule or to the main module, the + // latter potentially NULL. + // + if (!opt) + { + if (i->second == nullptr) + { + fail (loc) << "unable to load build system module " << i->first; + } + else if (i->first != smod) + { + fail (loc) << "build system module " << i->first << " has no " + << "submodule " << smod; + } + } + + // Note that if the main module exists but has no such submodule, we + // return NULL rather than fail (think of an older version of a module + // that doesn't implement some extra functionality). + // + return i->second; + } void - boot_module (scope& rs, const string& name, const location& loc) + boot_module (scope& rs, const string& mod, const location& loc) { - // First see if this modules has already been loaded for this project. + // First see if this modules has already been booted for this project. // - loaded_module_map& lm (rs.root_extra->modules); - auto i (lm.find (name)); + module_map& lm (rs.root_extra->modules); + auto i (lm.find (mod)); if (i != lm.end ()) { @@ -35,58 +271,48 @@ namespace build2 // Otherwise search for this module. // - auto j (builtin_modules.find (name)); - - if (j == builtin_modules.end ()) - fail (loc) << "unknown module " << name; - - const module_functions& mf (j->second); + const module_functions& mf ( + *find_module (rs, mod, loc, true /* boot */, false /* optional */)); if (mf.boot == nullptr) - fail (loc) << "module " << name << " shouldn't be loaded in bootstrap"; + fail (loc) << "build system module " << mod << " should not be loaded " + << "during bootstrap"; - i = lm.emplace (name, + i = lm.emplace (mod, module_state {true, false, mf.init, nullptr, loc}).first; i->second.first = mf.boot (rs, loc, i->second.module); - rs.assign (var_pool.rw (rs).insert (name + ".booted")) = true; + rs.assign (var_pool.rw (rs).insert (mod + ".booted")) = true; } bool - load_module (scope& rs, + init_module (scope& rs, scope& bs, - const string& name, + const string& mod, const location& loc, bool opt, const variable_map& hints) { - // First see if this modules has already been loaded for this project. + // First see if this modules has already been inited for this project. // - loaded_module_map& lm (rs.root_extra->modules); - auto i (lm.find (name)); + module_map& lm (rs.root_extra->modules); + auto i (lm.find (mod)); bool f (i == lm.end ()); if (f) { // Otherwise search for this module. // - auto j (builtin_modules.find (name)); - - if (j == builtin_modules.end ()) + if (const module_functions* mf = find_module ( + rs, mod, loc, false /* boot */, opt)) { - if (!opt) - fail (loc) << "unknown module " << name; - } - else - { - const module_functions& mf (j->second); - - if (mf.boot != nullptr) - fail (loc) << "module " << name << " should be loaded in bootstrap"; + if (mf->boot != nullptr) + fail (loc) << "build system module " << mod << " should be loaded " + << "during bootstrap"; i = lm.emplace ( - name, - module_state {false, false, mf.init, nullptr, loc}).first; + mod, + module_state {false, false, mf->init, nullptr, loc}).first; } } else @@ -103,11 +329,15 @@ namespace build2 // Note: pattern-typed in context.cxx:reset() as project-visibility // variables of type bool. // + // We call the variable 'loaded' rather than 'inited' because it is + // buildfile-visible (where we use the term "load a module"; see the note + // on terminology above) + // auto& vp (var_pool.rw (rs)); - value& lv (bs.assign (vp.insert (name + ".loaded"))); - value& cv (bs.assign (vp.insert (name + ".configured"))); + value& lv (bs.assign (vp.insert (mod + ".loaded"))); + value& cv (bs.assign (vp.insert (mod + ".configured"))); - bool l; // Loaded. + bool l; // Loaded (initialized). bool c; // Configured. // Suppress duplicate init() calls for the same module in the same scope. @@ -122,7 +352,7 @@ namespace build2 if (!opt) { if (!l) - fail (loc) << "unknown module " << name; + fail (loc) << "unable to load build system module " << mod; // We don't have original diagnostics. We could call init() again so // that it can issue it. But that means optional modules must be @@ -130,7 +360,8 @@ namespace build2 // simple for now. // if (!c) - fail (loc) << "module " << name << " failed to configure"; + fail (loc) << "build system module " << mod << " failed to " + << "configure"; } } else -- cgit v1.1