PR17290: Use 'false' macro in fix-it hint for initializing a variable of type

_Bool in C, if the macro is defined. Also teach FixItUtils to look at whether
the macro was defined at the source location for which it is creating a fixit,
rather than looking at whether it's defined *now*. This is especially relevant
for analysis-based warnings which are delayed until end of TU.

llvm-svn: 191057

1 files changed, 18 insertions, 10 deletions

diff --git a/clang/lib/Sema/SemaFixItUtils.cpp b/clang/lib/Sema/SemaFixItUtils.cpp
index 2a845ba9898..32b56bcddc6 100644
--- a/clang/lib/Sema/SemaFixItUtils.cpp
+++ b/clang/lib/Sema/SemaFixItUtils.cpp
@@ -160,27 +160,33 @@ bool ConversionFixItGenerator::tryToFixConversion(const Expr *FullExpr,
   return false;
 }
 
-static bool isMacroDefined(const Sema &S, StringRef Name) {
-  return S.PP.getMacroInfo(&S.getASTContext().Idents.get(Name));
+static bool isMacroDefined(const Sema &S, SourceLocation Loc, StringRef Name) {
+  const IdentifierInfo *II = &S.getASTContext().Idents.get(Name);
+  if (!II->hadMacroDefinition()) return false;
+
+  MacroDirective *Macro = S.PP.getMacroDirectiveHistory(II);
+  return Macro && Macro->findDirectiveAtLoc(Loc, S.getSourceManager());
 }
 
-static std::string getScalarZeroExpressionForType(const Type& T, const Sema& S) {
+static std::string getScalarZeroExpressionForType(
+    const Type &T, SourceLocation Loc, const Sema &S) {
   assert(T.isScalarType() && "use scalar types only");
   // Suggest "0" for non-enumeration scalar types, unless we can find a
   // better initializer.
   if (T.isEnumeralType())
     return std::string();
   if ((T.isObjCObjectPointerType() || T.isBlockPointerType()) &&
-      isMacroDefined(S, "nil"))
+      isMacroDefined(S, Loc, "nil"))
     return "nil";
   if (T.isRealFloatingType())
     return "0.0";
-  if (T.isBooleanType() && S.LangOpts.CPlusPlus)
+  if (T.isBooleanType() &&
+      (S.LangOpts.CPlusPlus || isMacroDefined(S, Loc, "false")))
     return "false";
   if (T.isPointerType() || T.isMemberPointerType()) {
     if (S.LangOpts.CPlusPlus11)
       return "nullptr";
-    if (isMacroDefined(S, "NULL"))
+    if (isMacroDefined(S, Loc, "NULL"))
       return "NULL";
   }
   if (T.isCharType())
@@ -194,9 +200,10 @@ static std::string getScalarZeroExpressionForType(const Type& T, const Sema& S)
   return "0";
 }
 
-std::string Sema::getFixItZeroInitializerForType(QualType T) const {
+std::string
+Sema::getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const {
   if (T->isScalarType()) {
-    std::string s = getScalarZeroExpressionForType(*T, *this);
+    std::string s = getScalarZeroExpressionForType(*T, Loc, *this);
     if (!s.empty())
       s = " = " + s;
     return s;
@@ -212,6 +219,7 @@ std::string Sema::getFixItZeroInitializerForType(QualType T) const {
   return std::string();
 }
 
-std::string Sema::getFixItZeroLiteralForType(QualType T) const {
-  return getScalarZeroExpressionForType(*T, *this);
+std::string
+Sema::getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const {
+  return getScalarZeroExpressionForType(*T, Loc, *this);
 }