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simplify CXXNameMangler::mangle, making it exit earlier for C functions. 

This speeds up a testcase in 3810 by ~16%.

llvm-svn: 67429
This commit is contained in:
Chris Lattner 2009-03-21 06:19:20 +00:00
parent 9b62dff5f6
commit cfbe9e746f
1 changed files with 31 additions and 30 deletions
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61
clang/lib/CodeGen/Mangle.cpp
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@ -62,40 +62,41 @@ bool CXXNameMangler::mangle(const NamedDecl *D) {
// ::= <special-name>
// FIXME: Actually use a visitor to decode these?
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
bool RequiresMangling = false;
// Clang's "overloadable" attribute extension to C/C++ implies
// name mangling (always).
if (FD->getAttr<OverloadableAttr>())
RequiresMangling = true;
// No mangled in an "implicit extern C" header.
else if (Context.getSourceManager().getFileCharacteristic(FD->getLocation())
== SrcMgr::C_ExternCSystem)
RequiresMangling = false;
else if (Context.getLangOptions().CPlusPlus && !FD->isMain()) {
// C++ requires name mangling, unless we're in a C linkage
// specification.
RequiresMangling = true;
const FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
if (!FD) // Can only mangle functions so far.
return false;
// Clang's "overloadable" attribute extension to C/C++ implies
// name mangling (always).
if (FD->getAttr<OverloadableAttr>())
; // fall into mangling code unconditionally.
else if (// C functions are not mangled
!Context.getLangOptions().CPlusPlus ||
// "main" is not mangled in C++
FD->isMain() ||
// No mangling in an "implicit extern C" header.
Context.getSourceManager().getFileCharacteristic(FD->getLocation())
== SrcMgr::C_ExternCSystem)
return false;
else {
// No name mangling in a C linkage specification.
for (const DeclContext *DC = FD->getDeclContext();
!DC->isTranslationUnit(); DC = DC->getParent()) {
if (const LinkageSpecDecl *Linkage = dyn_cast<LinkageSpecDecl>(DC)) {
// extern "C" functions don't use name mangling
if (Linkage->getLanguage() == LinkageSpecDecl::lang_c)
RequiresMangling = false;
break;
}
for (const DeclContext *DC = FD->getDeclContext();
!DC->isTranslationUnit(); DC = DC->getParent()) {
if (const LinkageSpecDecl *Linkage = dyn_cast<LinkageSpecDecl>(DC)) {
// extern "C" functions don't use name mangling.
if (Linkage->getLanguage() == LinkageSpecDecl::lang_c)
return false;
// Others do.
break;
}
}
}
if (RequiresMangling) {
Out << "_Z";
mangleFunctionEncoding(FD);
return true;
}
}
return false;
// If we get here, mangle the decl name!
Out << "_Z";
mangleFunctionEncoding(FD);
return true;
}
void CXXNameMangler::mangleFunctionEncoding(const FunctionDecl *FD) {