Make -Wformat walk the typedef chain when looking for size_t, etc.

Clang's -Wformat fix-its currently suggest using "%zu" for values of
type size_t (in C99 or C++11 mode). However, for a type such as
std::vector<T>::size_type, it does not notice that type is actually
typedeffed to size_t, and instead suggests a format for the underlying
type, such as "%lu" or "%u".

This commit makes the format string fix mechanism walk the typedef chain
so that it notices if the type is size_t, even if that isn't "at the
top".

llvm-svn: 160886

1 files changed, 2 insertions, 15 deletions

diff --git a/clang/lib/Analysis/ScanfFormatString.cpp b/clang/lib/Analysis/ScanfFormatString.cpp
index 066d5d6fa13..5c7e6ef8f27 100644
--- a/clang/lib/Analysis/ScanfFormatString.cpp
+++ b/clang/lib/Analysis/ScanfFormatString.cpp
@@ -382,21 +382,8 @@ bool ScanfSpecifier::fixType(QualType QT, const LangOptions &LangOpt,
   }
 
   // Handle size_t, ptrdiff_t, etc. that have dedicated length modifiers in C99.
-  if (isa<TypedefType>(PT) && (LangOpt.C99 || LangOpt.CPlusPlus0x)) {
-    const IdentifierInfo *Identifier = QT.getBaseTypeIdentifier();
-    if (Identifier->getName() == "size_t") {
-      LM.setKind(LengthModifier::AsSizeT);
-    } else if (Identifier->getName() == "ssize_t") {
-      // Not C99, but common in Unix.
-      LM.setKind(LengthModifier::AsSizeT);
-    } else if (Identifier->getName() == "intmax_t") {
-      LM.setKind(LengthModifier::AsIntMax);
-    } else if (Identifier->getName() == "uintmax_t") {
-      LM.setKind(LengthModifier::AsIntMax);
-    } else if (Identifier->getName() == "ptrdiff_t") {
-      LM.setKind(LengthModifier::AsPtrDiff);
-    }
-  }
+  if (isa<TypedefType>(PT) && (LangOpt.C99 || LangOpt.CPlusPlus0x))
+    namedTypeToLengthModifier(PT, LM);
 
   // If fixing the length modifier was enough, we are done.
   const analyze_scanf::ScanfArgTypeResult &ATR = getArgType(Ctx);