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//===--- CGCXXTemp.cpp - Emit LLVM Code for C++ temporaries ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with C++ code generation of temporaries
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
using namespace clang;
using namespace CodeGen;
void CodeGenFunction::PushCXXTemporary(const CXXTemporary *Temporary,
llvm::Value *Ptr) {
llvm::BasicBlock *DtorBlock = createBasicBlock("temp.dtor");
llvm::Value *CondPtr = 0;
// Check if temporaries need to be conditional. If so, we'll create a
// condition boolean, initialize it to 0 and
if (!ConditionalTempDestructionStack.empty()) {
CondPtr = CreateTempAlloca(llvm::Type::getInt1Ty(VMContext), "cond");
// Initialize it to false. This initialization takes place right after
// the alloca insert point.
llvm::StoreInst *SI =
new llvm::StoreInst(llvm::ConstantInt::getFalse(VMContext), CondPtr);
llvm::BasicBlock *Block = AllocaInsertPt->getParent();
Block->getInstList().insertAfter((llvm::Instruction *)AllocaInsertPt, SI);
// Now set it to true.
Builder.CreateStore(llvm::ConstantInt::getTrue(VMContext), CondPtr);
}
LiveTemporaries.push_back(CXXLiveTemporaryInfo(Temporary, Ptr, DtorBlock,
CondPtr));
PushCleanupBlock(DtorBlock);
}
void CodeGenFunction::PopCXXTemporary() {
const CXXLiveTemporaryInfo& Info = LiveTemporaries.back();
CleanupBlockInfo CleanupInfo = PopCleanupBlock();
assert(CleanupInfo.CleanupBlock == Info.DtorBlock &&
"Cleanup block mismatch!");
assert(!CleanupInfo.SwitchBlock &&
"Should not have a switch block for temporary cleanup!");
assert(!CleanupInfo.EndBlock &&
"Should not have an end block for temporary cleanup!");
EmitBlock(Info.DtorBlock);
llvm::BasicBlock *CondEnd = 0;
// If this is a conditional temporary, we need to check the condition
// boolean and only call the destructor if it's true.
if (Info.CondPtr) {
llvm::BasicBlock *CondBlock = createBasicBlock("cond.dtor.call");
CondEnd = createBasicBlock("cond.dtor.end");
llvm::Value *Cond = Builder.CreateLoad(Info.CondPtr);
Builder.CreateCondBr(Cond, CondBlock, CondEnd);
EmitBlock(CondBlock);
}
EmitCXXDestructorCall(Info.Temporary->getDestructor(),
Dtor_Complete, Info.ThisPtr);
if (CondEnd) {
// Reset the condition. to false.
Builder.CreateStore(llvm::ConstantInt::getFalse(VMContext), Info.CondPtr);
EmitBlock(CondEnd);
}
LiveTemporaries.pop_back();
}
RValue
CodeGenFunction::EmitCXXExprWithTemporaries(const CXXExprWithTemporaries *E,
llvm::Value *AggLoc,
bool IsAggLocVolatile,
bool IsInitializer) {
// If we shouldn't destroy the temporaries, just emit the
// child expression.
if (!E->shouldDestroyTemporaries())
return EmitAnyExpr(E->getSubExpr(), AggLoc, IsAggLocVolatile,
/*IgnoreResult=*/false, IsInitializer);
// Keep track of the current cleanup stack depth.
size_t CleanupStackDepth = CleanupEntries.size();
(void) CleanupStackDepth;
unsigned OldNumLiveTemporaries = LiveTemporaries.size();
RValue RV = EmitAnyExpr(E->getSubExpr(), AggLoc, IsAggLocVolatile,
/*IgnoreResult=*/false, IsInitializer);
// Pop temporaries.
while (LiveTemporaries.size() > OldNumLiveTemporaries)
PopCXXTemporary();
assert(CleanupEntries.size() == CleanupStackDepth &&
"Cleanup size mismatch!");
return RV;
}
void
CodeGenFunction::PushConditionalTempDestruction() {
// Store the current number of live temporaries.
ConditionalTempDestructionStack.push_back(LiveTemporaries.size());
}
void CodeGenFunction::PopConditionalTempDestruction() {
size_t NumLiveTemporaries = ConditionalTempDestructionStack.back();
ConditionalTempDestructionStack.pop_back();
// Pop temporaries.
while (LiveTemporaries.size() > NumLiveTemporaries) {
assert(LiveTemporaries.back().CondPtr &&
"Conditional temporary must have a cond ptr!");
PopCXXTemporary();
}
}
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