Fix <rdar://problem/6880975> [format string] Assertion failed: (Arg < NumArgs && "Arg access out of range!").

For format string checking, only check the type of the format
specifier for non-vararg functions.

llvm-svn: 71672

clang/lib/Sema/SemaChecking.cpp

@@ -917,7 +917,8 @@ void Sema::CheckPrintfString(const StringLiteral *FExpr,
     case '*': {
       ++numConversions;
       
-      if (!HasVAListArg && numConversions > numDataArgs) {
+      if (!HasVAListArg) {
+        if (numConversions > numDataArgs) {
           SourceLocation Loc = getLocationOfStringLiteralByte(FExpr, StrIdx);
 
           if (Str[StrIdx-1] == '.')
@@ -948,6 +949,7 @@ void Sema::CheckPrintfString(const StringLiteral *FExpr,
         
         break;        
       }
+    }
       
     // Characters which can terminate a format conversion
     // (e.g. "%d").  Characters that specify length modifiers or

clang/test/Sema/format-strings.c

@@ -125,3 +125,8 @@ void test9(char *P) {
   printf(P, 42);
   printf("%n", &x); // expected-warning {{use of '%n' in format string discouraged }}
 }
+
+void torture(va_list v8) {
+  vprintf ("%*.*d", v8);  // no-warning
+}
+