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Do not parse hexadecimal floating point literals in C++0x mode because they are 

incompatible with user-defined literals, specifically with the following form:

  0x1p+1

The preprocessing-number token extends only as far as the 'p'; the '+' is not
included. Previously we could get away with this extension as p was an invalid
suffix, but now with user-defined literals, 'p' might well be a valid suffix
and we are forced to consider it as such.

This patch also adds a warning in non-0x C++ modes telling the user that
this extension is incompatible with C++0x that is enabled by default
(previously and with other languages, we warn only with a compliance
option such as -pedantic).

llvm-svn: 93135
This commit is contained in:
Alexis Hunt 2010-01-10 23:37:56 +00:00
parent 504a6ae83e
commit 91b78382b5
4 changed files with 20 additions and 3 deletions
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3
clang/include/clang/Basic/DiagnosticLexKinds.td
View File

@ -84,6 +84,9 @@ def err_exponent_has_no_digits : Error<"exponent has no digits">;
def ext_imaginary_constant : Extension<"imaginary constants are an extension">;
def err_hexconstant_requires_exponent : Error<
"hexadecimal floating constants require an exponent">;
def ext_hexconstant_cplusplus : ExtWarn<
"hexadecimal floating constants are a C99 feature that is incompatible with "
"C++0x">;
def ext_hexconstant_invalid : Extension<
"hexadecimal floating constants are a C99 feature">;
def ext_binary_literal : Extension<

3
clang/lib/Lex/Lexer.cpp
View File

@ -724,7 +724,8 @@ void Lexer::LexNumericConstant(Token &Result, const char *CurPtr) {
return LexNumericConstant(Result, ConsumeChar(CurPtr, Size, Result));
// If we have a hex FP constant, continue.
if ((C == '-' || C == '+') && (PrevCh == 'P' || PrevCh == 'p'))
if ((C == '-' || C == '+') && (PrevCh == 'P' || PrevCh == 'p') &&
(!PP || !PP->getLangOptions().CPlusPlus0x))
return LexNumericConstant(Result, ConsumeChar(CurPtr, Size, Result));
// Update the location of token as well as BufferPtr.

9
clang/lib/Lex/LiteralSupport.cpp
View File

@ -458,7 +458,7 @@ void NumericLiteralParser::ParseNumberStartingWithZero(SourceLocation TokLoc) {
}
// A binary exponent can appear with or with a '.'. If dotted, the
// binary exponent is required.
if (*s == 'p' || *s == 'P') {
if ((*s == 'p' || *s == 'P') && !PP.getLangOptions().CPlusPlus0x) {
const char *Exponent = s;
s++;
saw_exponent = true;
@ -472,7 +472,12 @@ void NumericLiteralParser::ParseNumberStartingWithZero(SourceLocation TokLoc) {
}
s = first_non_digit;
if (!PP.getLangOptions().HexFloats)
// In C++0x, we cannot support hexadecmial floating literals because
// they conflict with user-defined literals, so we warn in previous
// versions of C++ by default.
if (PP.getLangOptions().CPlusPlus)
PP.Diag(TokLoc, diag::ext_hexconstant_cplusplus);
else if (!PP.getLangOptions().HexFloats)
PP.Diag(TokLoc, diag::ext_hexconstant_invalid);
} else if (saw_period) {
PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),

8
clang/test/Lexer/hexfloat.cpp Normal file
View File

@ -0,0 +1,8 @@
//RUN: %clang_cc1 -fsyntax-only -verify
//RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify
#ifndef __GXX_EXPERIMENTAL_CXX0X__
float f = 0x1p+1; // expected-warning {{incompatible with C++0x}}
#else
float f = 0x1p+1; // expected-warning {{invalid suffix}}
#endif