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authorJohn McCall <rjmccall@apple.com>2015-12-10 23:31:01 +0000
committerJohn McCall <rjmccall@apple.com>2015-12-10 23:31:01 +0000
commit83760378617dfa9670ce9439e9bfdcf2a5c81b90 (patch)
tree3001c116d3d00bbc1df3fe26a74d4568f85a68c4 /clang/lib
parent07206ea19dd55c8180d443a0d55a25bd67fb0858 (diff)
downloadbcm5719-llvm-83760378617dfa9670ce9439e9bfdcf2a5c81b90.tar.gz
bcm5719-llvm-83760378617dfa9670ce9439e9bfdcf2a5c81b90.zip
In Objective-C, ignore attempts to redefine the ARC/GC qualifier macros.
This works around existing system headers which unconditionally redefine these macros. This is reasonably safe to do because we used to warn about it anyway (outside of system headers). Continue to warn if the redefinition would have changed the expansion. Still permit redefinition if the macro is explicitly #undef'ed first. rdar://23788307 llvm-svn: 255311
Diffstat (limited to 'clang/lib')
-rw-r--r--clang/lib/Lex/PPDirectives.cpp24
1 files changed, 24 insertions, 0 deletions
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index fd16168203a..298543e2e95 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -2266,6 +2266,30 @@ void Preprocessor::HandleDefineDirective(Token &DefineTok,
// Finally, if this identifier already had a macro defined for it, verify that
// the macro bodies are identical, and issue diagnostics if they are not.
if (const MacroInfo *OtherMI=getMacroInfo(MacroNameTok.getIdentifierInfo())) {
+ // In Objective-C, ignore attempts to directly redefine the builtin
+ // definitions of the ownership qualifiers. It's still possible to
+ // #undef them.
+ auto isObjCProtectedMacro = [](const IdentifierInfo *II) -> bool {
+ return II->isStr("__strong") ||
+ II->isStr("__weak") ||
+ II->isStr("__unsafe_unretained") ||
+ II->isStr("__autoreleasing");
+ };
+ if (getLangOpts().ObjC1 &&
+ SourceMgr.getFileID(OtherMI->getDefinitionLoc())
+ == getPredefinesFileID() &&
+ isObjCProtectedMacro(MacroNameTok.getIdentifierInfo())) {
+ // Warn if it changes the tokens.
+ if ((!getDiagnostics().getSuppressSystemWarnings() ||
+ !SourceMgr.isInSystemHeader(DefineTok.getLocation())) &&
+ !MI->isIdenticalTo(*OtherMI, *this,
+ /*Syntactic=*/LangOpts.MicrosoftExt)) {
+ Diag(MI->getDefinitionLoc(), diag::warn_pp_objc_macro_redef_ignored);
+ }
+ assert(!OtherMI->isWarnIfUnused());
+ return;
+ }
+
// It is very common for system headers to have tons of macro redefinitions
// and for warnings to be disabled in system headers. If this is the case,
// then don't bother calling MacroInfo::isIdenticalTo.
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