Implement compiler_info caching

6 files changed, 62 insertions, 29 deletions

diff --git a/build2/cc/gcc.cxx b/build2/cc/gcc.cxx
index ec69524..523236a 100644
--- a/build2/cc/gcc.cxx
+++ b/build2/cc/gcc.cxx
@@ -28,7 +28,7 @@ namespace build2
     // (Clang, Intel) using the -v -E </dev/null method.
     //
     dir_paths config_module::
-    gcc_header_search_paths (process_path& xc, scope& rs) const
+    gcc_header_search_paths (const process_path& xc, scope& rs) const
     {
       dir_paths r;
 
@@ -161,7 +161,7 @@ namespace build2
     // (Clang, Intel) using the -print-search-dirs option.
     //
     dir_paths config_module::
-    gcc_library_search_paths (process_path& xc, scope& rs) const
+    gcc_library_search_paths (const process_path& xc, scope& rs) const
     {
       dir_paths r;
 
diff --git a/build2/cc/guess.cxx b/build2/cc/guess.cxx
index 32c3166..9299885 100644
--- a/build2/cc/guess.cxx
+++ b/build2/cc/guess.cxx
@@ -4,6 +4,7 @@
 
 #include <build2/cc/guess.hxx>
 
+#include <map>
 #include <cstring>  // strlen(), strchr()
 
 #include <build2/diagnostics.hxx>
@@ -44,12 +45,12 @@ namespace build2
     //
     static string
     stdlib (lang xl,
-            const process_path& xc,
+            const process_path& xp,
             const strings* c_po, const strings* x_po,
             const strings* c_co, const strings* x_co,
             const char* src)
     {
-      cstrings args {xc.recall_string ()};
+      cstrings args {xp.recall_string ()};
       if (c_po != nullptr) append_options (args, *c_po);
       if (x_po != nullptr) append_options (args, *x_po);
       if (c_co != nullptr) append_options (args, *c_co);
@@ -72,6 +73,7 @@ namespace build2
       // options but that we simply leave to blow up later).
       //
       process pr (run_start (3     /* verbosity */,
+                             xp,
                              args.data (),
                              -1    /* stdin */,
                              -1    /* stdout */,
@@ -268,7 +270,7 @@ namespace build2
 
       guess_result r;
 
-      process_path xp (run_search (xc, true));
+      process_path xp (run_search (xc, false /* init */)); // Note: cached.
 
       // Start with -v. This will cover gcc and clang.
       //
@@ -601,7 +603,7 @@ namespace build2
       // multi-arch support), then use the result. Otherwise, fallback to
       // -dumpmachine (older gcc or not multi-arch).
       //
-      cstrings args {xc.string ().c_str (), "-print-multiarch"};
+      cstrings args {xp.recall_string (), "-print-multiarch"};
       if (c_co != nullptr) append_options (args, *c_co);
       if (x_co != nullptr) append_options (args, *x_co);
       args.push_back (nullptr);
@@ -1042,7 +1044,7 @@ namespace build2
       // "Intel(R)" "64"
       // "Intel(R)" "MIC"      (-dumpmachine says: x86_64-k1om-linux)
       //
-      cstrings args {xc.string ().c_str (), "-V"};
+      cstrings args {xp.recall_string (), "-V"};
       if (c_co != nullptr) append_options (args, *c_co);
       if (x_co != nullptr) append_options (args, *x_co);
       args.push_back (nullptr);
@@ -1408,13 +1410,38 @@ namespace build2
         move (xsl)};
     }
 
-    compiler_info
+    // Compiler checks can be expensive (we often need to run the compiler
+    // several times) so we cache the result.
+    //
+    static map<string, compiler_info> cache;
+
+    const compiler_info&
     guess (lang xl,
            const path& xc,
            const strings* c_po, const strings* x_po,
            const strings* c_co, const strings* x_co,
            const strings* c_lo, const strings* x_lo)
     {
+      // First check the cache.
+      //
+      string key;
+      {
+        sha256 cs;
+        cs.append (static_cast<size_t> (xl));
+        cs.append (xc.string ());
+        if (c_po != nullptr) hash_options (cs, *c_po);
+        if (x_po != nullptr) hash_options (cs, *x_po);
+        if (c_co != nullptr) hash_options (cs, *c_co);
+        if (x_co != nullptr) hash_options (cs, *x_co);
+        if (c_lo != nullptr) hash_options (cs, *c_lo);
+        if (x_lo != nullptr) hash_options (cs, *x_lo);
+        key = cs.string ();
+
+        auto i (cache.find (key));
+        if (i != cache.end ())
+          return i->second;
+      }
+
       string pre (pre_guess (xl, xc));
       guess_result gr;
 
@@ -1520,7 +1547,7 @@ namespace build2
           r.bin_pattern = p.directory ().representation (); // Trailing slash.
       }
 
-      return r;
+      return (cache[key] = move (r));
     }
 
     path
diff --git a/build2/cc/guess.hxx b/build2/cc/guess.hxx
index d6ca28d..8c291a9 100644
--- a/build2/cc/guess.hxx
+++ b/build2/cc/guess.hxx
@@ -202,7 +202,7 @@ namespace build2
     // of fur in multiple places doesn't seem wise, especially considering
     // that most of it will be the same, at least for C and C++.
     //
-    compiler_info
+    const compiler_info&
     guess (lang,
            const path& xc,
            const strings* c_poptions, const strings* x_poptions,
diff --git a/build2/cc/module.cxx b/build2/cc/module.cxx
index 1020bd6..c56bca9 100644
--- a/build2/cc/module.cxx
+++ b/build2/cc/module.cxx
@@ -107,14 +107,15 @@ namespace build2
       // Figure out which compiler we are dealing with, its target, etc.
       //
       const path& xc (cast<path> (*p.first));
-      ci = build2::cc::guess (x_lang,
-                              xc,
-                              cast_null<strings> (rs[config_c_poptions]),
-                              cast_null<strings> (rs[config_x_poptions]),
-                              cast_null<strings> (rs[config_c_coptions]),
-                              cast_null<strings> (rs[config_x_coptions]),
-                              cast_null<strings> (rs[config_c_loptions]),
-                              cast_null<strings> (rs[config_x_loptions]));
+      ci_ = &build2::cc::guess (x_lang,
+                                xc,
+                                cast_null<strings> (rs[config_c_poptions]),
+                                cast_null<strings> (rs[config_x_poptions]),
+                                cast_null<strings> (rs[config_c_coptions]),
+                                cast_null<strings> (rs[config_x_coptions]),
+                                cast_null<strings> (rs[config_c_loptions]),
+                                cast_null<strings> (rs[config_x_loptions]));
+      const compiler_info& ci (*ci_);
 
       // Split/canonicalize the target. First see if the user asked us to
       // use config.sub.
@@ -262,6 +263,7 @@ namespace build2
     {
       tracer trace (x, "config_init");
 
+      const compiler_info& ci (*ci_);
       const target_triplet& tt (cast<target_triplet> (rs[x_target]));
 
       // Translate x_std value (if any) to the compiler option(s) (if any).
@@ -398,12 +400,12 @@ namespace build2
         }
       }
 
-      rs.assign (x_path) = move (ci.path);
+      rs.assign (x_path) = process_path (ci.path, false /* init */);
       rs.assign (x_sys_lib_dirs) = move (lib_dirs);
       rs.assign (x_sys_inc_dirs) = move (inc_dirs);
 
-      rs.assign (x_signature) = move (ci.signature);
-      rs.assign (x_checksum) = move (ci.checksum);
+      rs.assign (x_signature) = ci.signature;
+      rs.assign (x_checksum) = ci.checksum;
 
       // config.x.{p,c,l}options
       // config.x.libs
@@ -440,7 +442,7 @@ namespace build2
         variable_map h;
 
         if (!ci.bin_pattern.empty ())
-          h.assign ("config.bin.pattern") = move (ci.bin_pattern);
+          h.assign ("config.bin.pattern") = ci.bin_pattern;
 
         load_module (rs, rs, "cc.core.config", loc, false, h);
       }
diff --git a/build2/cc/module.hxx b/build2/cc/module.hxx
index 928e16c..de61611 100644
--- a/build2/cc/module.hxx
+++ b/build2/cc/module.hxx
@@ -52,20 +52,24 @@ namespace build2
       size_t sys_lib_dirs_extra; // First extra path (size if none).
       size_t sys_inc_dirs_extra; // First extra path (size if none).
 
-      compiler_info ci; // Note: some members are moved from.
+      const compiler_info* ci_;
 
     private:
+      // Defined in gcc.cxx.
+      //
       dir_paths
-      gcc_header_search_paths (process_path&, scope&) const; // gcc.cxx
+      gcc_header_search_paths (const process_path&, scope&) const;
 
       dir_paths
-      gcc_library_search_paths (process_path&, scope&) const; // gcc.cxx
+      gcc_library_search_paths (const process_path&, scope&) const;
 
+      // Defined in msvc.cxx.
+      //
       dir_paths
-      msvc_header_search_paths (process_path&, scope&) const; // msvc.cxx
+      msvc_header_search_paths (const process_path&, scope&) const;
 
       dir_paths
-      msvc_library_search_paths (process_path&, scope&) const; // msvc.cxx
+      msvc_library_search_paths (const process_path&, scope&) const;
 
     private:
       bool new_; // See guess() and init() for details.
diff --git a/build2/cc/msvc.cxx b/build2/cc/msvc.cxx
index b418f78..1d94f66 100644
--- a/build2/cc/msvc.cxx
+++ b/build2/cc/msvc.cxx
@@ -86,7 +86,7 @@ namespace build2
     // Extract system header search paths from MSVC.
     //
     dir_paths config_module::
-    msvc_header_search_paths (process_path&, scope&) const
+    msvc_header_search_paths (const process_path&, scope&) const
     {
       // The compiler doesn't seem to have any built-in paths and all of them
       // come from the INCLUDE environment variable.
@@ -105,7 +105,7 @@ namespace build2
     // Extract system library search paths from MSVC.
     //
     dir_paths config_module::
-    msvc_library_search_paths (process_path&, scope&) const
+    msvc_library_search_paths (const process_path&, scope&) const
     {
       // The linker doesn't seem to have any built-in paths and all of them
       // come from the LIB environment variable.