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PP: Implement token pasting for PP identifiers.

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Implement token pasting as per the C++ specification, within the current
style of the PP code.
Non-identifiers (turning 12 ## 10 into the numeral 1210) is not yet covered;
they should be a simple incremental change built on this one.
Addresses issue #255.
This commit is contained in:
John Kessenich 2016-12-19 09:19:43 -07:00
parent abf5057948
commit d485e0b710
10 changed files with 304 additions and 34 deletions
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46
glslang/MachineIndependent/preprocessor/PpScanner.cpp
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@ -739,6 +739,11 @@ const char* TPpContext::tokenize(TPpToken* ppToken)
for(;;) {
token = scanToken(ppToken);
ppToken->token = token;
// Handle token-pasting logic
token = tokenPaste(*ppToken);
ppToken->token = token;
if (token == EndOfInput) {
missingEndifCheck();
return nullptr;
@ -800,6 +805,47 @@ const char* TPpContext::tokenize(TPpToken* ppToken)
}
}
//
// Do all token-pasting related combining of two pasted tokens when getting a
// stream of tokens from a replacement list. Degenerates to no processing if a
// replacement list is not the source of the token stream.
//
int TPpContext::tokenPaste(TPpToken& ppToken)
{
// starting with ## is illegal, skip to next token
if (ppToken.token == PpAtomPaste) {
parseContext.ppError(ppToken.loc, "unexpected location", "##", "");
ppToken.token = scanToken(&ppToken);
}
// ## can be chained, process all in the chain at once
while (peekPasting()) {
TPpToken pastedPpToken;
// next token has to be ##
pastedPpToken.token = scanToken(&pastedPpToken);
assert(pastedPpToken.token == PpAtomPaste);
if (endOfReplacementList()) {
parseContext.ppError(ppToken.loc, "unexpected location; end of replacement list", "##", "");
break;
}
// get the token after the ##
scanToken(&pastedPpToken);
// combine the tokens
if (strlen(ppToken.name) + strlen(pastedPpToken.name) > MaxTokenLength)
parseContext.ppError(ppToken.loc, "combined tokens are too long", "##", "");
strncat(ppToken.name, pastedPpToken.name, MaxTokenLength - strlen(ppToken.name));
ppToken.atom = LookUpAddString(ppToken.name);
if (ppToken.token != PpAtomIdentifier)
parseContext.ppError(ppToken.loc, "only supported for preprocessing identifiers", "##", "");
}
return ppToken.token;
}
// Checks if we've seen balanced #if...#endif
void TPpContext::missingEndifCheck()
{