Fix a bug that warnings generated with -M or -MM flags

This is a patch for bug: https://bugs.llvm.org/show_bug.cgi?id=6817

Warnings should not be emitted with -M and -MM flags, because this mode
is only used for generate MakeFiles.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@305561 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index 6d3dbb5b52043541d29f0927f728baa706fccab6..bd4e894d6504b3a2a1905a05303bc2a3a78a6d00 100644 (file)
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -980,6 +980,9 @@ void Clang::AddPreprocessingOptions(Compilation &C, const JobAction &JA,
         DepTarget = Args.MakeArgString(llvm::sys::path::filename(P));
       }
 
+      if (!A->getOption().matches(options::OPT_MD) && !A->getOption().matches(options::OPT_MMD)) {
+        CmdArgs.push_back("-w");
+      }
       CmdArgs.push_back("-MT");
       SmallString<128> Quoted;
       QuoteTarget(DepTarget, Quoted);

diff --git a/test/Driver/m_and_mm.c b/test/Driver/m_and_mm.c
index 18cf7abfa629de41e29eb05648ce47740df3f17d..e4d59bc70e2e2c1f22825aaa25204a88191c55f7 100644 (file)
--- a/test/Driver/m_and_mm.c
+++ b/test/Driver/m_and_mm.c
@@ -1,3 +1,15 @@
 // RUN: %clang -### \
 // RUN:   -M -MM %s 2> %t
 // RUN: not grep '"-sys-header-deps"' %t
+
+// RUN: %clang -M -MM %s 2> %t
+// RUN: not grep "warning" %t
+
+// RUN: %clang -MMD -MD %s 2> %t
+// RUN: grep "warning" %t
+
+#warning "This warning shouldn't show up with -M and -MM"
+int main (void)
+{
+    return 0;
+}