Add two flags to the CC1 layer that I was hoping to avoid. We need to

encode the *exact* semantics which the header search paths internally
built by the Frontend layer have had, which is both non-user-provided,
and at times adding the implicit extern "C" bit to the directory entry.

There are lots of CC1 options that are very close, but none do quite
this, and they are all already overloaded for other purposes. In some
senses this makes the command lines more clean as it clearly indicates
which flags are exclusively used to implement internal detection of
"standard" header search paths.

Lots of the implementation of this is really crufty, due to the
surrounding cruft. It doesn't seem worth investing lots of time cleaning
this up as it isn't new, and hopefully *lots* of this code will melt
away as header search inside of the frontend becomes increasingly
trivial.

llvm-svn: 143798

1 files changed, 19 insertions, 4 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 399e0ca8d86..1829d7de0ad 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -575,10 +575,16 @@ static void HeaderSearchOptsToArgs(const HeaderSearchOptions &Opts,
         break;
       }
     } else {
-      if (E.Group != frontend::Angled && E.Group != frontend::System)
-        llvm::report_fatal_error("Invalid option set!");
-      Res.push_back(E.Group == frontend::Angled ? "-iwithprefixbefore" :
-                    "-iwithprefix");
+      if (E.IsInternal) {
+        assert(E.Group == frontend::System && "Unexpected header search group");
+        Res.push_back(E.ImplicitExternC ? "-internal-externc-isystem"
+                                        : "-internal-isystem");
+      } else {
+        if (E.Group != frontend::Angled && E.Group != frontend::System)
+          llvm::report_fatal_error("Invalid option set!");
+        Res.push_back(E.Group == frontend::Angled ? "-iwithprefixbefore" :
+                      "-iwithprefix");
+      }
     }
     Res.push_back(E.Path);
   }
@@ -1483,6 +1489,15 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
        ie = Args.filtered_end(); it != ie; ++it)
     Opts.AddPath((*it)->getValue(Args), frontend::ObjCXXSystem, true, false,
                  true);
+
+  // Add the internal paths from a driver that detects standard include paths.
+  for (arg_iterator I = Args.filtered_begin(OPT_internal_isystem,
+                                            OPT_internal_externc_isystem),
+                    E = Args.filtered_end();
+       I != E; ++I)
+    Opts.AddPath((*I)->getValue(Args), frontend::System,
+                 false, false, false, /*IsInternal=*/true,
+                 (*I)->getOption().matches(OPT_internal_externc_isystem));
 }
 
 void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,