[cfe-commits] r140777 - in /cfe/trunk: lib/Sema/SemaChecking.cpp test/Sema/format-strings.c

[Ted Kremenek]

Author: kremenek
Date: Thu Sep 29 00:52:16 2011
New Revision: 140777

URL: http://llvm.org/viewvc/llvm-project?rev=140777&view=rev
Log:
Do not warn about empty format strings when there are no data arguments.  Fixes <rdar://problem/9473155>.

Modified:
    cfe/trunk/lib/Sema/SemaChecking.cpp
    cfe/trunk/test/Sema/format-strings.c

Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=140777&r1=140776&r2=140777&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Thu Sep 29 00:52:16 2011
@@ -1880,9 +1880,10 @@
   StringRef StrRef = FExpr->getString();
   const char *Str = StrRef.data();
   unsigned StrLen = StrRef.size();
+  const unsigned numDataArgs = TheCall->getNumArgs() - firstDataArg;
   
   // CHECK: empty format string?
-  if (StrLen == 0) {
+  if (StrLen == 0 && numDataArgs > 0) {
     Diag(FExpr->getLocStart(), diag::warn_empty_format_string)
     << OrigFormatExpr->getSourceRange();
     return;
@@ -1890,18 +1891,16 @@
   
   if (isPrintf) {
     CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
-                         TheCall->getNumArgs() - firstDataArg,
-                         isa<ObjCStringLiteral>(OrigFormatExpr), Str,
-                         HasVAListArg, TheCall, format_idx);
+                         numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr),
+                         Str, HasVAListArg, TheCall, format_idx);
   
     if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen))
       H.DoneProcessing();
   }
   else {
     CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
-                        TheCall->getNumArgs() - firstDataArg,
-                        isa<ObjCStringLiteral>(OrigFormatExpr), Str,
-                        HasVAListArg, TheCall, format_idx);
+                        numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr),
+                        Str, HasVAListArg, TheCall, format_idx);
     
     if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen))
       H.DoneProcessing();

Modified: cfe/trunk/test/Sema/format-strings.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/format-strings.c?rev=140777&r1=140776&r2=140777&view=diff
==============================================================================
--- cfe/trunk/test/Sema/format-strings.c (original)
+++ cfe/trunk/test/Sema/format-strings.c Thu Sep 29 00:52:16 2011
@@ -87,7 +87,12 @@
   va_list ap;
   va_start(ap,buf);
   vprintf("",ap); // expected-warning {{format string is empty}}
-  sprintf(buf,""); // expected-warning {{format string is empty}}
+  sprintf(buf, "", 1); // expected-warning {{format string is empty}}
+  
+  // Don't warn about empty format strings when there are no data arguments.
+  // This can arise from macro expansions and non-standard format string
+  // functions.
+  sprintf(buf, ""); // no-warning
 }
 
 void check_wide_string(char* b, ...)