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Convert to StringRef, avoid a memcpy in the common case. 

llvm-svn: 92357
This commit is contained in:
Benjamin Kramer 2009-12-31 13:32:38 +00:00
parent 15e77a2fd3
commit 14488464be
1 changed files with 16 additions and 19 deletions
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35
clang/lib/Lex/PPDirectives.cpp
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@ -220,32 +220,28 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
// Get the identifier name without trigraphs or embedded newlines. Note
// that we can't use Tok.getIdentifierInfo() because its lookup is disabled
// when skipping.
// TODO: could do this with zero copies in the no-clean case by using
// strncmp below.
char Directive[20];
unsigned IdLen;
char DirectiveBuf[20];
llvm::StringRef Directive;
if (!Tok.needsCleaning() && Tok.getLength() < 20) {
IdLen = Tok.getLength();
memcpy(Directive, RawCharData, IdLen);
Directive[IdLen] = 0;
Directive = llvm::StringRef(RawCharData, Tok.getLength());
} else {
std::string DirectiveStr = getSpelling(Tok);
IdLen = DirectiveStr.size();
unsigned IdLen = DirectiveStr.size();
if (IdLen >= 20) {
CurPPLexer->ParsingPreprocessorDirective = false;
// Restore comment saving mode.
if (CurLexer) CurLexer->SetCommentRetentionState(KeepComments);
continue;
}
memcpy(Directive, &DirectiveStr[0], IdLen);
Directive[IdLen] = 0;
FirstChar = Directive[0];
memcpy(DirectiveBuf, &DirectiveStr[0], IdLen);
Directive = llvm::StringRef(DirectiveBuf, IdLen);
}
if (FirstChar == 'i' && Directive[1] == 'f') {
if ((IdLen == 2) || // "if"
(IdLen == 5 && !strcmp(Directive+2, "def")) || // "ifdef"
(IdLen == 6 && !strcmp(Directive+2, "ndef"))) { // "ifndef"
if (Directive.startswith("if")) {
llvm::StringRef Sub = Directive.substr(2);
if (Sub.empty() || // "if"
Sub == "def" || // "ifdef"
Sub == "ndef") { // "ifndef"
// We know the entire #if/#ifdef/#ifndef block will be skipped, don't
// bother parsing the condition.
DiscardUntilEndOfDirective();
@ -253,8 +249,9 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
/*foundnonskip*/false,
/*fnddelse*/false);
}
} else if (FirstChar == 'e') {
if (IdLen == 5 && !strcmp(Directive+1, "ndif")) { // "endif"
} else if (Directive[0] == 'e') {
llvm::StringRef Sub = Directive.substr(1);
if (Sub == "ndif") { // "endif"
CheckEndOfDirective("endif");
PPConditionalInfo CondInfo;
CondInfo.WasSkipping = true; // Silence bogus warning.
@ -265,7 +262,7 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
// If we popped the outermost skipping block, we're done skipping!
if (!CondInfo.WasSkipping)
break;
} else if (IdLen == 4 && !strcmp(Directive+1, "lse")) { // "else".
} else if (Sub == "lse") { // "else".
// #else directive in a skipping conditional. If not in some other
// skipping conditional, and if #else hasn't already been seen, enter it
// as a non-skipping conditional.
@ -284,7 +281,7 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
CondInfo.FoundNonSkip = true;
break;
}
} else if (IdLen == 4 && !strcmp(Directive+1, "lif")) { // "elif".
} else if (Sub == "lif") { // "elif".
PPConditionalInfo &CondInfo = CurPPLexer->peekConditionalLevel();
bool ShouldEnter;