Enable modules support only for VC 15u5 and up, drop hacks for earlier

5 files changed, 20 insertions, 94 deletions

diff --git a/build2/cc/compile-rule.cxx b/build2/cc/compile-rule.cxx
index e77ef08..1e1d45d 100644
--- a/build2/cc/compile-rule.cxx
+++ b/build2/cc/compile-rule.cxx
@@ -2991,41 +2991,15 @@ namespace build2
             if (ps)
               psrc.active = true; // Re-arm.
 
-            // Prior to 15u5 VC was not using the 'export module' syntax so we
-            // use the preprequisite type to distinguish between interface and
-            // implementation units.
+            // Prior to 15u5 (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 (cid == compiler_id::msvc &&
                 cmaj == 19 && cmin <= 11 &&
                 x_mod != nullptr && src.is_a (*x_mod))
             {
-              // It's quite painful to guard the export with an #if/#endif so
-              // if it is present, "fixup" the (temporary) preprocessed output
-              // by getting rid of the keyword.
-              //
-              // Note: when removing this also remember to remove the test.
-              //
-              if (tu.mod.iface)
-              {
-                // We can only fixup a temporary file.
-                //
-                if (!ps)
-                  fail (relative (src)) << "fixup requires preprocessor";
-
-                // Stomp out the export keyword with spaces. We are using
-                // std::fstream since our fdstream does not yet support
-                // seeking.
-                //
-                fstream os (psrc.path.string (), fstream::out | fstream::in);
-                auto pos (static_cast<fstream::pos_type> (p.export_pos));
-
-                if (!os.is_open ()  ||
-                    !os.seekp (pos) ||
-                    !os.write ("      ", 6))
-                  fail << "unable to overwrite preprocessor output";
-              }
-              else
-                tu.mod.iface = true;
+              tu.mod.iface = true;
             }
 
             return pair<translation_unit, string> (move (tu), p.checksum);
diff --git a/build2/cc/parser.cxx b/build2/cc/parser.cxx
index fcb6265..c8fcf4b 100644
--- a/build2/cc/parser.cxx
+++ b/build2/cc/parser.cxx
@@ -82,23 +82,14 @@ namespace build2
               }
               else if (id == "export")
               {
-                uint64_t pos (t.position);
-
                 switch (l_->next (t))
                 {
                 case type::lcbrace:    ++bb; ex = true; break;
                 case type::identifier:
                   {
-                    if      (id == "module")
-                    {
-                      export_pos = pos;
-                      parse_module (t, true);
-                    }
-                    else if (id == "import")
-                      parse_import (t, true);
-                    else
-                      n = false; // Something else (e.g., export namespace).
-
+                    if      (id == "module") parse_module (t, true);
+                    else if (id == "import") parse_import (t, true);
+                    else n = false; // Something else (e.g., export namespace).
                     break;
                   }
                 default: n = false; break;
diff --git a/build2/cc/parser.hxx b/build2/cc/parser.hxx
index bec67bd..a4fd5f8 100644
--- a/build2/cc/parser.hxx
+++ b/build2/cc/parser.hxx
@@ -39,7 +39,6 @@ namespace build2
 
     public:
       string checksum;     // Translation unit checksum.
-      uint64_t export_pos; // Temporary hack, see parse_unit().
 
     private:
       lexer* l_;
diff --git a/build2/cxx/init.cxx b/build2/cxx/init.cxx
index ff97f5b..826d2b0 100644
--- a/build2/cxx/init.cxx
+++ b/build2/cxx/init.cxx
@@ -163,10 +163,10 @@ namespace build2
                 // While modules are supported in VC15u0 (19.10), there is a
                 // bug in separate interface/implementation unit support which
                 // makes them pretty much unusable. This has been fixed in
-                // VC15u3 (19.11). And VC15u5 supports the 'export module M;'
-                // syntax.
+                // VC15u3 (19.11). And VC15u5 (19.12) supports the 'export
+                // module M;' syntax.
                 //
-                if (mj > 19 || (mj == 19 && mi >= (l ? 10 : 11)))
+                if (mj > 19 || (mj == 19 && mi >= (l ? 10 : 12)))
                 {
                   r.push_back (
                     mj > 19 || mi > 11
diff --git a/tests/cc/modules/testscript b/tests/cc/modules/testscript
index a2b057d..ac46451 100644
--- a/tests/cc/modules/testscript
+++ b/tests/cc/modules/testscript
@@ -22,10 +22,10 @@ cxx.features.modules = true
 
 using cxx
 
-# We forced modules but for VC we need at least 15u3 (19.11). So "unforce"
+# We forced modules but for VC we need at least 15u5 (19.12). So "unforce"
 # them in this case.
 #
-if ($cxx.id == 'msvc' && $cxx.version.major == 19 && $cxx.version.minor < 11)
+if ($cxx.id == 'msvc' && $cxx.version.major == 19 && $cxx.version.minor < 12)
   cxx.features.modules = false
 
 hxx{*}: extension = hxx
@@ -53,11 +53,7 @@ EOI
 #  define LIBFOO_EXPORT
 #endif
 
-#if __cpp_modules >= 201704
-export
-#endif
-module foo.core;
-
+export module foo.core;
 export LIBFOO_EXPORT int f (int);
 EOI
 
@@ -123,10 +119,7 @@ $* test clean <<EOI
   # "Bad" match which we should better.
   #
   +cat <<EOI >=core.mxx
-    #if __cpp_modules >= 201704
-    export
-    #endif
-    module bar.core;
+    export module bar.core;
     EOI
 
   : separator
@@ -202,11 +195,7 @@ $* test clean <<EOI
 :
 {
   +cat <<EOI >=base.mxx
-    #if __cpp_modules >= 201704
-    export
-    #endif
-    module foo.base;
-
+    export module foo.base;
     export import foo.core;
     EOI
 
@@ -215,10 +204,7 @@ $* test clean <<EOI
     #  define LIBFOO_EXPORT
     #endif
 
-    #if __cpp_modules >= 201704
-    export
-    #endif
-    module foo.extra;
+    export module foo.extra;
 
     export
     {
@@ -231,10 +217,7 @@ $* test clean <<EOI
     EOI
 
   +cat <<EOI >=foo.mxx
-    #if __cpp_modules >= 201704
-    export
-    #endif
-    module foo;
+    export module foo;
 
     export
     {
@@ -290,8 +273,6 @@ $* test clean <<EOI
 : entire, recursively-explored list of BMIs.
 :
 {
-  # Note: using VC export module fixup support.
-
   +cat <<EOI >=base.mxx
     export module foo.base;
     import foo.core;
@@ -329,10 +310,7 @@ $* test clean <<EOI
 :
 ln -s ../core.mxx ../core.cxx ../driver.cxx ./;
 cat <<EOI >=foo-core.mxx;
-  #if __cpp_modules >= 201704
-  export
-  #endif
-  module foo.core;
+  export module foo.core;
   export inline int f (int i) {return i - 2;}
   EOI
 $* update <<EOI;
@@ -359,10 +337,7 @@ $* test clean <<EOI
 : Test the __symexport feature.
 :
 cat <<EOI >=core.mxx;
-  #if __cpp_modules >= 201704
-  export
-  #endif
-  module foo.core;
+  export module foo.core;
 
   export __symexport int f (int);
 
@@ -381,18 +356,5 @@ cat <<EOI >=driver.cxx;
 $* test clean <<EOI
   ./: lib{foo} exe{test} # Full build.
   exe{test}: cxx{driver} lib{foo}
-  lib{foo}: mxx{core} cxx{core-f} # core-g @@ VC
-  EOI
-
-: export-fixup
-:
-: Test removing the export keyword for VC compatibility.
-:
-ln -s ../core.cxx ../driver.cxx ./;
-cat <<EOI >=core.mxx;
-  export module foo.core;
-  export int f (int);
+  lib{foo}: mxx{core} cxx{core-f} # @@ VC: core-g
   EOI
-$* test <'exe{test}: cxx{driver core} mxx{core}';
-touch core.mxx; # Test use of cached .ii's.
-$* test clean <'exe{test}: cxx{driver core} mxx{core}'