Avoid warning on "clang -c -Dfoo test.i". Lines like these are created

when using ccache and libtool.m4 assumes that the compiler cannot print
warnings about options it knows about.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135723 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index c54ced2d1d0648cdbe69783d19393458129c8b11..2fb865e020759d00a862f125002d1b173df1e0e8 100644 (file)
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1459,6 +1459,12 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   if (types::getPreprocessedType(InputType) != types::TY_INVALID)
     AddPreprocessingOptions(D, Args, CmdArgs, Output, Inputs);
 
+  // Don't warn about "clang -c -DPIC -fPIC test.i" because libtool.m4 assumes
+  // that "The compiler can only warn and ignore the option if not recognized".
+  // When building with ccache, it will pass -D options to clang even on
+  // preprocessed inputs and configure concludes that -fPIC is not supported.
+  Args.ClaimAllArgs(options::OPT_D);
+
   // Manually translate -O to -O2 and -O4 to -O3; let clang reject
   // others.
   if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {