[cfe-commits] r44339 - in /cfe/trunk: Lex/LiteralSupport.cpp include/clang/Lex/LiteralSupport.h

[Neil Booth]

Hi Ted,

Ted Kremenek wrote:-

>  llvm::APFloat NumericLiteralParser::
> -GetFloatValue(const llvm::fltSemantics &Format) {
> +GetFloatValue(const llvm::fltSemantics &Format, bool* isExact) {
> +  using llvm::APFloat;
> +  
>    char floatChars[256];
>    strncpy(floatChars, ThisTokBegin, ThisTokEnd-ThisTokBegin);
>    floatChars[ThisTokEnd-ThisTokBegin] = '\0';

I realize you didn't write it but that local buffer overflow
has to go :)

If ThisTokEnd points to a valid character that cannot continue
the literal, then pass ThisTokBegin and be done with it - APFloat
parses until the first character that is syntactically incorrect;
it assumes the caller has verified the syntax.  In other words
\0 is just one example of a suitable terminator; almost anything
outside [0-9.eE+-pP] will do.

> +#if 1
> +  APFloat V (Format, APFloat::fcZero, false);
> +
> +  APFloat::opStatus status;
> +  status = V.convertFromString(floatChars,APFloat::rmTowardZero);
> +  
> +  if (isExact)
> +    *isExact = status == APFloat::opOK;
> +  
> +  return V;

I think in general we should be rounding to nearest, not zero.

Neil.