[Sema][ObjC] Fix a -Wformat false positive with localizedStringForKey

Only honour format_arg attributes on -[NSBundle localizedStringForKey] when its
argument has a format specifier in it, otherwise its likely to just be a key to
fetch localized strings.

Fixes rdar://23622446

Differential revision: https://reviews.llvm.org/D27165

llvm-svn: 368878

1 files changed, 17 insertions, 0 deletions

diff --git a/clang/lib/AST/PrintfFormatString.cpp b/clang/lib/AST/PrintfFormatString.cpp
index 68f78299a0f..bae60d46440 100644
--- a/clang/lib/AST/PrintfFormatString.cpp
+++ b/clang/lib/AST/PrintfFormatString.cpp
@@ -463,6 +463,23 @@ bool clang::analyze_format_string::ParseFormatStringHasSArg(const char *I,
   return false;
 }
 
+bool clang::analyze_format_string::parseFormatStringHasFormattingSpecifiers(
+    const char *Begin, const char *End, const LangOptions &LO,
+    const TargetInfo &Target) {
+  unsigned ArgIndex = 0;
+  // Keep looking for a formatting specifier until we have exhausted the string.
+  FormatStringHandler H;
+  while (Begin != End) {
+    const PrintfSpecifierResult &FSR =
+        ParsePrintfSpecifier(H, Begin, End, ArgIndex, LO, Target, false, false);
+    if (FSR.shouldStop())
+      break;
+    if (FSR.hasValue())
+      return true;
+  }
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // Methods on PrintfSpecifier.
 //===----------------------------------------------------------------------===//