Add support for supplying MSVC IFCPATH equivalent

7 files changed, 64 insertions, 13 deletions

diff --git a/libbuild2/c/init.cxx b/libbuild2/c/init.cxx
index 7129f37..423e6af 100644
--- a/libbuild2/c/init.cxx
+++ b/libbuild2/c/init.cxx
@@ -354,6 +354,7 @@ namespace build2
 
         cast<dir_paths> (rs[cm.x_sys_lib_dirs]),
         cast<dir_paths> (rs[cm.x_sys_inc_dirs]),
+        cm.x_info->sys_mod_dirs,
 
         cm.sys_lib_dirs_extra,
         cm.sys_inc_dirs_extra,
diff --git a/libbuild2/cc/common.hxx b/libbuild2/cc/common.hxx
index 0548d6f..84d287c 100644
--- a/libbuild2/cc/common.hxx
+++ b/libbuild2/cc/common.hxx
@@ -162,8 +162,9 @@ namespace build2
       const strings* xlate_hdr;     // x.translatable_headers (NULL if
                                     // unused/empty).
 
-      const dir_paths& sys_lib_dirs; // x.sys_lib_dirs
-      const dir_paths& sys_inc_dirs; // x.sys_inc_dirs
+      const dir_paths&           sys_lib_dirs; // x.sys_lib_dirs
+      const dir_paths&           sys_inc_dirs; // x.sys_inc_dirs
+      const optional<dir_paths>& sys_mod_dirs; // compiler_info::sys_mod_dirs
 
       size_t sys_lib_dirs_extra;     // First extra path (size if none).
       size_t sys_inc_dirs_extra;     // First extra path (size if none).
@@ -213,6 +214,7 @@ namespace build2
             bool fs,
             const dir_paths& sld,
             const dir_paths& sid,
+            const optional<dir_paths>& smd,
             size_t sle,
             size_t sie,
             const target_type& src,
@@ -232,7 +234,7 @@ namespace build2
             modules (fm),
             symexport (fs),
             xlate_hdr (nullptr),
-            sys_lib_dirs (sld), sys_inc_dirs (sid),
+            sys_lib_dirs (sld), sys_inc_dirs (sid), sys_mod_dirs (smd),
             sys_lib_dirs_extra (sle), sys_inc_dirs_extra (sie),
             x_src (src), x_mod (mod), x_hdr (hdr), x_inc (inc) {}
     };
diff --git a/libbuild2/cc/compile-rule.cxx b/libbuild2/cc/compile-rule.cxx
index c0f876c..98b78e1 100644
--- a/libbuild2/cc/compile-rule.cxx
+++ b/libbuild2/cc/compile-rule.cxx
@@ -5576,11 +5576,24 @@ namespace build2
       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");
+      if (getenv ("IFCPATH"))
+      {
+        // 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");
+      }
+      else if (stdifc.empty ())
+      {
+        // Add the VC's default directory (should be only one).
+        //
+        if (sys_mod_dirs && !sys_mod_dirs->empty ())
+        {
+          args.push_back ("/module:stdIfcDir");
+          args.push_back (sys_mod_dirs->front ().string ().c_str ());
+        }
+      }
     }
 
     target_state compile_rule::
diff --git a/libbuild2/cc/guess.cxx b/libbuild2/cc/guess.cxx
index c37b6b6..053a4cb 100644
--- a/libbuild2/cc/guess.cxx
+++ b/libbuild2/cc/guess.cxx
@@ -1360,7 +1360,7 @@ namespace build2
     // do that probably first checking if they exist/empty).
     //
     static dir_paths
-    msvc_include (const msvc_info& mi)
+    msvc_inc (const msvc_info& mi)
     {
       dir_paths r;
 
@@ -1382,6 +1382,19 @@ namespace build2
       return r;
     }
 
+    // Return the MSVC system module search paths (i.e., what the Visual
+    // Studio command prompt puts into IFCPATH).
+    //
+    static dir_paths
+    msvc_mod (const msvc_info& mi, const char* cpu)
+    {
+      dir_paths r;
+
+      r.push_back ((dir_path (mi.msvc_dir) /= "ifc") /= cpu);
+
+      return r;
+    }
+
     // Return the MSVC system library search paths (i.e., what the Visual
     // Studio command prompt puts into LIB).
     //
@@ -1601,10 +1614,11 @@ namespace build2
 
       // If we have the MSVC installation information, then this means we are
       // running out of the Visual Studio command prompt and will have to
-      // supply PATH/INCLUDE/LIB equivalents ourselves.
+      // supply PATH/INCLUDE/LIB/IFCPATH equivalents ourselves.
       //
       optional<dir_paths> lib_dirs;
       optional<dir_paths> inc_dirs;
+      optional<dir_paths> mod_dirs;
       string bpat;
 
       if (const msvc_info* mi = static_cast<msvc_info*> (gr.info.get ()))
@@ -1612,7 +1626,9 @@ namespace build2
         const char* cpu (msvc_cpu (target_triplet (t).cpu));
 
         lib_dirs = msvc_lib (*mi, cpu);
-        inc_dirs = msvc_include (*mi);
+        inc_dirs = msvc_inc (*mi);
+        mod_dirs = msvc_mod (*mi, cpu);
+
         bpat = msvc_bin (*mi, cpu);
       }
 
@@ -1654,7 +1670,8 @@ namespace build2
         move (csl),
         move (xsl),
         move (lib_dirs),
-        move (inc_dirs)};
+        move (inc_dirs),
+        move (mod_dirs)};
     }
 
     static compiler_info
@@ -1852,6 +1869,7 @@ namespace build2
         move (csl),
         move (xsl),
         nullopt,
+        nullopt,
         nullopt};
     }
 
@@ -2438,6 +2456,7 @@ namespace build2
         move (csl),
         move (xsl),
         move (lib_dirs),
+        nullopt,
         nullopt};
     }
 
@@ -2743,6 +2762,7 @@ namespace build2
         move (csl),
         move (xsl),
         nullopt,
+        nullopt,
         nullopt};
     }
 
diff --git a/libbuild2/cc/guess.hxx b/libbuild2/cc/guess.hxx
index d93aaf9..b32aaa9 100644
--- a/libbuild2/cc/guess.hxx
+++ b/libbuild2/cc/guess.hxx
@@ -227,10 +227,12 @@ namespace build2
       string c_stdlib;
       string x_stdlib;
 
-      // System library/header search paths, if extracted at the guess stage.
+      // System library/header/module search paths, if extracted at the guess
+      // stage.
       //
       optional<dir_paths> sys_lib_dirs;
       optional<dir_paths> sys_inc_dirs;
+      optional<dir_paths> sys_mod_dirs;
     };
 
     // In a sense this is analagous to the language standard which we handle
diff --git a/libbuild2/cc/module.cxx b/libbuild2/cc/module.cxx
index 5f8652e..881583f 100644
--- a/libbuild2/cc/module.cxx
+++ b/libbuild2/cc/module.cxx
@@ -403,8 +403,11 @@ namespace build2
       // Extract system header/library search paths from the compiler and
       // determine if we need any additional search paths.
       //
+      // Note that for now module search paths only come from compiler_info.
+      //
       dir_paths lib_dirs;
       dir_paths inc_dirs;
+      const optional<dir_paths>& mod_dirs (xi.sys_mod_dirs);
 
       if (xi.sys_lib_dirs)
         lib_dirs = *xi.sys_lib_dirs;
@@ -599,6 +602,15 @@ namespace build2
           dr << "\n  pattern    " << xi.pattern;
         }
 
+        if (verb >= 3 && mod_dirs && !mod_dirs->empty ())
+        {
+          dr << "\n  mod dirs";
+          for (const dir_path& d: *mod_dirs)
+          {
+            dr << "\n    " << d;
+          }
+        }
+
         if (verb >= 3 && !inc_dirs.empty ())
         {
           dr << "\n  inc dirs";
diff --git a/libbuild2/cxx/init.cxx b/libbuild2/cxx/init.cxx
index 851ea0c..8e641b5 100644
--- a/libbuild2/cxx/init.cxx
+++ b/libbuild2/cxx/init.cxx
@@ -626,6 +626,7 @@ namespace build2
 
         cast<dir_paths> (rs[cm.x_sys_lib_dirs]),
         cast<dir_paths> (rs[cm.x_sys_inc_dirs]),
+        cm.x_info->sys_mod_dirs,
 
         cm.sys_lib_dirs_extra,
         cm.sys_inc_dirs_extra,