Add --suppress-system-warnings (on by default, use =0 to disable)

 - For investigating warnings in system headers / builtins.
 - Currently also enables the behavior that allows silent redefinition
   of types in system headers. Conceptually these are separate but I
   didn't feel it was worth two options (or changing LangOptions).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@56163 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 5 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 726372356e..2f4350766a 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -276,11 +276,13 @@ TypedefDecl *Sema::MergeTypeDefDecl(TypedefDecl *New, Decl *OldD) {
   // *either* declaration is in a system header. The code below implements
   // this adhoc compatibility rule. FIXME: The following code will not
   // work properly when compiling ".i" files (containing preprocessed output).
-  SourceManager &SrcMgr = Context.getSourceManager();
-  if (SrcMgr.isInSystemHeader(Old->getLocation()))
-    return New;
-  if (SrcMgr.isInSystemHeader(New->getLocation()))
-    return New;
+  if (PP.getDiagnostics().getSuppressSystemWarnings()) {
+    SourceManager &SrcMgr = Context.getSourceManager();
+    if (SrcMgr.isInSystemHeader(Old->getLocation()))
+      return New;
+    if (SrcMgr.isInSystemHeader(New->getLocation()))
+      return New;
+  }
 
   Diag(New->getLocation(), diag::err_redefinition, New->getName());
   Diag(Old->getLocation(), diag::err_previous_definition);