Incorporate project environment checksum into cc::compiler_info cache key

8 files changed, 60 insertions, 3 deletions

diff --git a/libbuild2/bin/guess.cxx b/libbuild2/bin/guess.cxx
index 219b8e8..8dd3cb6 100644
--- a/libbuild2/bin/guess.cxx
+++ b/libbuild2/bin/guess.cxx
@@ -363,6 +363,9 @@ namespace build2
     //    will need to figure out what's important (some of them are clearly
     //    for debugging of ld itself).
     //
+    // See also the note on environment and caching below if adding any new
+    // variables.
+    //
     static const char* gnu_ld_env[] = {
       "LD_RUN_PATH", "GNUTARGET", "LDEMULATION", "COLLECT_NO_DEMANGLE", nullptr};
 
@@ -381,6 +384,9 @@ namespace build2
 
       // First check the cache.
       //
+      // Note that none of the information that we cache can be affected by
+      // the environment.
+      //
       string key;
       {
         sha256 cs;
@@ -569,6 +575,9 @@ namespace build2
 
     // Resource compiler environment variables.
     //
+    // See also the note on environment and caching below if adding any new
+    // variables.
+    //
     static const char* msvc_rc_env[] = {"INCLUDE", nullptr};
 
     // Extracting rc information requires running it which can become
@@ -583,6 +592,9 @@ namespace build2
 
       // First check the cache.
       //
+      // Note that none of the information that we cache can be affected by
+      // the environment.
+      //
       string key;
       {
         sha256 cs;
diff --git a/libbuild2/bin/guess.hxx b/libbuild2/bin/guess.hxx
index e5da263..3307999 100644
--- a/libbuild2/bin/guess.hxx
+++ b/libbuild2/bin/guess.hxx
@@ -31,6 +31,9 @@ namespace build2
     // The environment is an optional list of environment variables that
     // affect ar/ranlib result.
     //
+    // Watch out for the environment not to affect any of the extracted
+    // information since we cache it.
+    //
     struct ar_info
     {
       process_path ar_path;
@@ -80,6 +83,9 @@ namespace build2
     // The environment is an optional list of environment variables that
     // affect the linker result.
     //
+    // Watch out for the environment not to affect any of the extracted
+    // information since we cache it.
+    //
     // Note that for now the version is extracted only for some linkers. Once
     // it's done for all of them, we should drop optional.
     //
@@ -113,6 +119,9 @@ namespace build2
     // The environment is an optional list of environment variables that
     // affect the resource compiler result.
     //
+    // Watch out for the environment not to affect any of the extracted
+    // information since we cache it.
+    //
     struct rc_info
     {
       process_path path;
diff --git a/libbuild2/cc/guess.cxx b/libbuild2/cc/guess.cxx
index 839bf20..ff96466 100644
--- a/libbuild2/cc/guess.cxx
+++ b/libbuild2/cc/guess.cxx
@@ -1577,6 +1577,9 @@ namespace build2
     // but we include them in case linking is done via the compiler without
     // loading bin.ld. BTW, the same applies to rc.exe INCLUDE.
     //
+    // See also the note on environment and caching below if adding any new
+    // variables.
+    //
     static const char* msvc_env[] = {"INCLUDE", "IFCPATH", "CL", "_CL_",
                                      "LIB", "LINK", "_LINK_", nullptr};
 
@@ -1822,6 +1825,9 @@ namespace build2
     // would need to detect which linker is being used at which point we might
     // as well load bin.ld).
     //
+    // See also the note on environment and caching below if adding any new
+    // variables.
+    //
     static const char* gcc_c_env[] = {
       "CPATH", "C_INCLUDE_PATH",
       "LIBRARY_PATH", "LD_RUN_PATH",
@@ -2275,6 +2281,8 @@ namespace build2
     // These are derived from gcc_* plus the sparse documentation (clang(1))
     // and source code.
     //
+    // See also the note on environment and caching below if adding any new
+    // variables.
     //
     static const char* clang_c_env[] = {
       "CPATH", "C_INCLUDE_PATH",
@@ -3064,6 +3072,7 @@ namespace build2
     const compiler_info&
     guess (const char* xm,
            lang xl,
+           const string& ec,
            const path& xc,
            const string* xis,
            const string* xv,
@@ -3075,6 +3084,13 @@ namespace build2
     {
       // First check the cache.
       //
+      // Note that in case of MSVC (and Clang targeting MSVC) sys_*_dirs can
+      // be affected by the environment (INCLUDE, LIB, and IFCPATH) which is
+      // project-specific. So we have to include those into the key. But we
+      // don't know yet know whether it's those compilers/targets. So it seems
+      // we have no better choice than to include the project environment if
+      // overridden.
+      //
       // @@ We currently include config.{cc,x}.[pc]options into the key which
       //    means any project-specific tweaks to these result in a different
       //    key. Perhaps we should assume that any options that can affect the
@@ -3087,6 +3103,7 @@ namespace build2
         sha256 cs;
         cs.append (static_cast<size_t> (xl));
         cs.append (xc.string ());
+        if (!ec.empty ()) cs.append (ec);
         if (xis != nullptr) cs.append (*xis);
         append_options (cs, x_mo);
         if (c_po != nullptr) append_options (cs, *c_po);
diff --git a/libbuild2/cc/guess.hxx b/libbuild2/cc/guess.hxx
index 6bab649..0180c97 100644
--- a/libbuild2/cc/guess.hxx
+++ b/libbuild2/cc/guess.hxx
@@ -173,6 +173,9 @@ namespace build2
     // search paths (similar to the PATH environment variable), in which case
     // it will end with a directory separator but will not contain '*'.
     //
+    // Watch out for the environment variables affecting any of the extracted
+    // information (like sys_*_dirs) since we cache it.
+    //
     struct compiler_info
     {
       process_path path;
@@ -252,6 +255,7 @@ namespace build2
     const compiler_info&
     guess (const char* xm,        // Module (for var names in diagnostics).
            lang xl,               // Language.
+           const string& ec,      // Environment checksum.
            const path& xc,        // Compiler path.
            const string* xi,      // Compiler id (optional).
            const string* xv,      // Compiler version (optional).
diff --git a/libbuild2/cc/module.cxx b/libbuild2/cc/module.cxx
index 98e0451..44f1943 100644
--- a/libbuild2/cc/module.cxx
+++ b/libbuild2/cc/module.cxx
@@ -154,7 +154,9 @@ namespace build2
         // we are now folding *.std options into mode options.
         //
         x_info = &build2::cc::guess (
-          x, x_lang, move (xc),
+          x, x_lang,
+          rs.root_extra->environment_checksum,
+          move (xc),
           cast_null<string> (lookup_config (rs, config_x_id)),
           cast_null<string> (lookup_config (rs, config_x_version)),
           cast_null<string> (lookup_config (rs, config_x_target)),
diff --git a/libbuild2/config/init.cxx b/libbuild2/config/init.cxx
index 7b810bd..87b492c 100644
--- a/libbuild2/config/init.cxx
+++ b/libbuild2/config/init.cxx
@@ -455,13 +455,15 @@ namespace build2
         rs.vars.erase (c_e); // Undefine.
       }
 
-      // Copy config.config.environment to scope::root_extra::environment.
+      // Copy config.config.environment to scope::root_extra::environment and
+      // calculate its checksum.
       //
       // Note that we store shallow copies that point to the c.c.environment
       // value which means it should not change.
       //
       if (const strings* src = cast_null<strings> (rs[c_e]))
       {
+        sha256 cs;
         vector<const char*>& dst (rs.root_extra->environment);
 
         // The idea is to only copy entries that are effective, that is those
@@ -511,10 +513,14 @@ namespace build2
           }
 
           dst.push_back (v.c_str ());
+          cs.append (v);
         }
 
         if (!dst.empty ())
+        {
           dst.push_back (nullptr);
+          rs.root_extra->environment_checksum = cs.string ();
+        }
       }
 
       // Register alias and fallback rule for the configure meta-operation.
diff --git a/libbuild2/file.cxx b/libbuild2/file.cxx
index 02ad71d..8bc84e2 100644
--- a/libbuild2/file.cxx
+++ b/libbuild2/file.cxx
@@ -610,7 +610,8 @@ namespace build2
         {}, /* modules */
         {}, /* override_cache */
         {}, /* target_types */
-        {}} /* environment */);
+        {}, /* environment */
+        ""} /* environment_checksum */);
 
     // Enter built-in meta-operation and operation names. Loading of
     // modules (via the src bootstrap; see below) can result in
diff --git a/libbuild2/scope.hxx b/libbuild2/scope.hxx
index 9f88dc9..f78a565 100644
--- a/libbuild2/scope.hxx
+++ b/libbuild2/scope.hxx
@@ -501,6 +501,12 @@ namespace build2
       // See also auto_project_env below.
       //
       vector<const char*> environment;
+
+      // A checksum of the above environment variables (empty if there are
+      // none). This can be used to take into account project environment
+      // when, for example, caching environment-sensitive information.
+      //
+      string environment_checksum;
     };
 
     unique_ptr<root_extra_type> root_extra;