nicolas/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

PR20473: Don't "deduplicate" string literals with the same value but different

Browse Source 
lengths! In passing, simplify string literal deduplication by relying on LLVM
to deduplicate the underlying constant values.

llvm-svn: 214222
This commit is contained in:
Richard Smith
2014-07-29 21:20:12 +00:00
parent 9d2250ad43
commit 00db2f13f8
3 changed files with 21 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
clang/lib/CodeGen/CodeGenModule.cpp
View File

@@ -2773,10 +2773,11 @@ CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
auto Alignment =
getContext().getAlignOfGlobalVarInChars(S->getType()).getQuantity();
llvm::StringMapEntry<llvm::GlobalVariable *> *Entry = nullptr;
llvm::Constant *C = GetConstantArrayFromStringLiteral(S);
llvm::GlobalVariable **Entry = nullptr;
if (!LangOpts.WritableStrings) {
Entry = getConstantStringMapEntry(S->getBytes(), S->getCharByteWidth());
if (auto GV = Entry->getValue()) {
Entry = &ConstantStringMap[C];
if (auto GV = *Entry) {
if (Alignment > GV->getAlignment())
GV->setAlignment(Alignment);
return GV;
@@ -2803,10 +2804,9 @@ CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
GlobalVariableName = ".str";
}
llvm::Constant *C = GetConstantArrayFromStringLiteral(S);
auto GV = GenerateStringLiteral(C, LT, *this, GlobalVariableName, Alignment);
if (Entry)
Entry->setValue(GV);
*Entry = GV;
reportGlobalToASan(GV, S->getStrTokenLoc(0), "<string literal>");
return GV;
@@ -2822,26 +2822,6 @@ CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) {
return GetAddrOfConstantCString(Str);
}
llvm::StringMapEntry<llvm::GlobalVariable *> *CodeGenModule::getConstantStringMapEntry(
StringRef Str, int CharByteWidth) {
llvm::StringMap<llvm::GlobalVariable *> *ConstantStringMap = nullptr;
switch (CharByteWidth) {
case 1:
ConstantStringMap = &Constant1ByteStringMap;
break;
case 2:
ConstantStringMap = &Constant2ByteStringMap;
break;
case 4:
ConstantStringMap = &Constant4ByteStringMap;
break;
default:
llvm_unreachable("unhandled byte width!");
}
return &ConstantStringMap->GetOrCreateValue(Str);
}
/// GetAddrOfConstantCString - Returns a pointer to a character array containing
/// the literal and a terminating '\0' character.
/// The result has pointer to array type.
@@ -2854,19 +2834,20 @@ llvm::GlobalVariable *CodeGenModule::GetAddrOfConstantCString(
.getQuantity();
}
llvm::Constant *C =
llvm::ConstantDataArray::getString(getLLVMContext(), StrWithNull, false);
// Don't share any string literals if strings aren't constant.
llvm::StringMapEntry<llvm::GlobalVariable *> *Entry = nullptr;
llvm::GlobalVariable **Entry = nullptr;
if (!LangOpts.WritableStrings) {
Entry = getConstantStringMapEntry(StrWithNull, 1);
if (auto GV = Entry->getValue()) {
Entry = &ConstantStringMap[C];
if (auto GV = *Entry) {
if (Alignment > GV->getAlignment())
GV->setAlignment(Alignment);
return GV;
}
}
llvm::Constant *C =
llvm::ConstantDataArray::getString(getLLVMContext(), StrWithNull, false);
// Get the default prefix if a name wasn't specified.
if (!GlobalName)
GlobalName = ".str";
@@ -2874,7 +2855,7 @@ llvm::GlobalVariable *CodeGenModule::GetAddrOfConstantCString(
auto GV = GenerateStringLiteral(C, llvm::GlobalValue::PrivateLinkage, *this,
GlobalName, Alignment);
if (Entry)
Entry->setValue(GV);
*Entry = GV;
return GV;
}