Enhancements to the alternate (WIP) format string checking:

- Add ConversionSpecifier::consumesDataArgument() as a helper method
  to determine if a conversion specifier requires a matching argument.
- Add support for glibc-specific '%m' conversion
- Add an extra callback to HandleNull() for locations within the
  format specifier that have a null character

llvm-svn: 94834

clang/include/clang/Analysis/Analyses/PrintfFormatString.h

@@ -46,6 +46,8 @@ public:
    PercentArg,    // '%'
     // Objective-C specific specifiers.
    ObjCObjArg,    // '@'
+    // GlibC specific specifiers.
+   PrintErrno,    // 'm'
     // Specifier ranges.
    IntArgBeg = dArg,
    IntArgEnd = iArg,
@@ -69,6 +71,16 @@ public:
     return Position;
   }
 	
+  bool consumesDataArgument() const {
+    switch (kind) {
+  	  case PercentArg:
+	  case PrintErrno:
+		return false;
+	  default:
+		return true;
+	}
+  }
+  
   bool isObjCArg() const { return kind >= ObjCBeg && kind <= ObjCEnd; }
   bool isIntArg() const { return kind >= dArg && kind <= iArg; }
   bool isUIntArg() const { return kind >= oArg && kind <= XArg; }

clang/lib/Analysis/PrintfFormatString.cpp

@@ -192,6 +192,12 @@ static FormatSpecifierResult ParseFormatSpecifier(FormatStringHandler &H,
     return true;
   }
 	
+  if (*I == '\0') {
+	// Detect spurious null characters, which are likely errors.
+	H.HandleNullChar(I);
+	return true;
+  }
+  
   // Finally, look for the conversion specifier.
   const char *conversionPosition = I++;
   ConversionSpecifier::Kind k = ConversionSpecifier::InvalidSpecifier;
@@ -220,6 +226,8 @@ static FormatSpecifierResult ParseFormatSpecifier(FormatStringHandler &H,
     case '%': k = ConversionSpecifier::PercentArg;   break;      
     // Objective-C.
     case '@': k = ConversionSpecifier::ObjCObjArg; break;
+	// Glibc specific.
+    case 'm': k = ConversionSpecifier::PrintErrno; break;
   }
   FS.setConversionSpecifier(ConversionSpecifier(conversionPosition, k));
 
@@ -246,7 +254,7 @@ bool clang::ParseFormatString(FormatStringHandler &H,
     // We have a format specifier.  Pass it to the callback.
     if (!H.HandleFormatSpecifier(FSR.getValue(), FSR.getStart(),
                                  I - FSR.getStart()))
-      return false;
+      return true;
   }  
   assert(I == E && "Format string not exhausted");      
   return false;