Fix diagnostic pragmas.

Diagnostic pragmas are broken because we don't keep track of the diagnostic state changes and we only check the current/latest state.
Problems manifest if a diagnostic is emitted for a source line that has different diagnostic state than the current state; this can affect
a lot of places, like C++ inline methods, template instantiations, the lexer, etc.

Fix the issue by having the Diagnostic object keep track of the source location of the pragmas so that it is able to know what is the diagnostic state at any given source location.

Fixes rdar://8365684.

llvm-svn: 121873

1 files changed, 14 insertions, 6 deletions

diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 3414c27bfc8..467d4858883 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -1504,11 +1504,6 @@ void Preprocessor::HandleDefineDirective(Token &DefineTok) {
     }
   }
 
-  // If this is the primary source file, remember that this macro hasn't been
-  // used yet.
-  if (isInPrimaryFile())
-    MI->setIsUsed(false);
-
   MI->setDefinitionEndLoc(LastTok.getLocation());
 
   // Finally, if this identifier already had a macro defined for it, verify that
@@ -1536,6 +1531,16 @@ void Preprocessor::HandleDefineDirective(Token &DefineTok) {
 
   setMacroInfo(MacroNameTok.getIdentifierInfo(), MI);
 
+  assert(!MI->isUsed());
+  // If we need warning for not using the macro, add its location in the
+  // warn-because-unused-macro set. If it gets used it will be removed from set.
+  if (isInPrimaryFile() && // don't warn for include'd macros.
+      Diags->getDiagnosticLevel(diag::pp_macro_not_used,
+                               MI->getDefinitionLoc()) != Diagnostic::Ignored) {
+    MI->setIsWarnIfUnused(true);
+    WarnUnusedMacroLocs.insert(MI->getDefinitionLoc());
+  }
+
   // If the callbacks want to know, tell them about the macro definition.
   if (Callbacks)
     Callbacks->MacroDefined(MacroNameTok, MI);
@@ -1569,6 +1574,9 @@ void Preprocessor::HandleUndefDirective(Token &UndefTok) {
   if (Callbacks)
     Callbacks->MacroUndefined(MacroNameTok, MI);
 
+  if (MI->isWarnIfUnused())
+    WarnUnusedMacroLocs.erase(MI->getDefinitionLoc());
+
   // Free macro definition.
   ReleaseMacroInfo(MI);
   setMacroInfo(MacroNameTok.getIdentifierInfo(), 0);
@@ -1621,7 +1629,7 @@ void Preprocessor::HandleIfdefDirective(Token &Result, bool isIfndef,
 
   // If there is a macro, process it.
   if (MI)  // Mark it used.
-    MI->setIsUsed(true);
+    markMacroAsUsed(MI);
 
   // Should we include the stuff contained by this directive?
   if (!MI == isIfndef) {