Make conversion specifier warning refer to typedef if possible.

For example, the warning for printf("%zu", 42.0);
changes from "conversion specifies type 'unsigned long'" to "conversion
specifies type 'size_t' (aka 'unsigned long')"

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@145697 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 5 deletions

diff --git a/lib/Analysis/PrintfFormatString.cpp b/lib/Analysis/PrintfFormatString.cpp
index 70dbfd30ce..b37b23f3b1 100644
--- a/lib/Analysis/PrintfFormatString.cpp
+++ b/lib/Analysis/PrintfFormatString.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Analysis/Analyses/FormatString.h"
+#include "clang/Sema/Sema.h"
 #include "FormatStringParsing.h"
 
 using clang::analyze_format_string::ArgTypeResult;
@@ -278,8 +279,27 @@ const char *ConversionSpecifier::toString() const {
 // Methods on PrintfSpecifier.
 //===----------------------------------------------------------------------===//
 
-ArgTypeResult PrintfSpecifier::getArgType(ASTContext &Ctx) const {
+/// \brief Try to find and return a typedef type named Name whose actual type
+/// is Underlying. Return Underlying if such a typedef cannot be found.
+static QualType FindTypedef(Sema &S, const char *Name, QualType Underlying) {
+  ASTContext &Ctx = S.getASTContext();
+  IdentifierInfo &II = Ctx.Idents.get(Name);
+
+  NamedDecl *D = S.LookupSingleName(S.getCurScope(), DeclarationName(&II),
+                                    SourceLocation(), Sema::LookupOrdinaryName);
+
+  if (TypedefDecl *TD = dyn_cast_or_null<TypedefDecl>(D)) {
+    QualType TypedefType = Ctx.getTypedefType(TD, QualType());
+    if (TD->getUnderlyingType() == Underlying)
+      return TypedefType;
+  }
+
+  return Underlying;
+}
+
+ArgTypeResult PrintfSpecifier::getArgType(Sema &S) const {
   const PrintfConversionSpecifier &CS = getConversionSpecifier();
+  ASTContext &Ctx = S.getASTContext();
 
   if (!CS.consumesDataArgument())
     return ArgTypeResult::Invalid();
@@ -301,11 +321,13 @@ ArgTypeResult PrintfSpecifier::getArgType(ASTContext &Ctx) const {
       case LengthModifier::AsShort: return Ctx.ShortTy;
       case LengthModifier::AsLong: return Ctx.LongTy;
       case LengthModifier::AsLongLong: return Ctx.LongLongTy;
-      case LengthModifier::AsIntMax: return Ctx.getIntMaxType();
+      case LengthModifier::AsIntMax:
+        return FindTypedef(S, "intmax_t", Ctx.getIntMaxType());
       case LengthModifier::AsSizeT:
         // FIXME: How to get the corresponding signed version of size_t?
         return ArgTypeResult();
-      case LengthModifier::AsPtrDiff: return Ctx.getPointerDiffType();
+      case LengthModifier::AsPtrDiff:
+        return FindTypedef(S, "ptrdiff_t", Ctx.getPointerDiffType());
     }
 
   if (CS.isUIntArg())
@@ -317,9 +339,10 @@ ArgTypeResult PrintfSpecifier::getArgType(ASTContext &Ctx) const {
       case LengthModifier::AsShort: return Ctx.UnsignedShortTy;
       case LengthModifier::AsLong: return Ctx.UnsignedLongTy;
       case LengthModifier::AsLongLong: return Ctx.UnsignedLongLongTy;
-      case LengthModifier::AsIntMax: return Ctx.getUIntMaxType();
+      case LengthModifier::AsIntMax:
+        return FindTypedef(S, "uintmax_t", Ctx.getUIntMaxType());
       case LengthModifier::AsSizeT:
-        return Ctx.getSizeType();
+        return FindTypedef(S, "size_t", Ctx.getSizeType());
       case LengthModifier::AsPtrDiff:
         // FIXME: How to get the corresponding unsigned
         // version of ptrdiff_t?