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Implement clang support for indirect branch and address of label

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using the new LLVM support for this.  This is temporarily hiding
behind horrible and ugly #ifdefs until the time when the optimizer
is stable (hopefully a week or so).  Until then, lets make it "opt in" :)

llvm-svn: 85446
This commit is contained in:
Chris Lattner
2009-10-28 23:59:40 +00:00
parent 48d9995d2b
commit 6c4d255bf3
6 changed files with 107 additions and 0 deletions
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68
clang/lib/CodeGen/CodeGenFunction.cpp
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@@ -27,7 +27,11 @@ CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
: BlockFunction(cgm, *this, Builder), CGM(cgm),
Target(CGM.getContext().Target),
Builder(cgm.getModule().getContext()),
#ifndef USEINDIRECTBRANCH
DebugInfo(0), IndirectGotoSwitch(0),
#else
DebugInfo(0), IndirectBranch(0),
#endif
SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0),
CXXThisDecl(0) {
LLVMIntTy = ConvertType(getContext().IntTy);
@@ -130,10 +134,33 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
EmitFunctionEpilog(*CurFnInfo, ReturnValue);
#ifdef USEINDIRECTBRANCH
// If someone did an indirect goto, emit the indirect goto block at the end of
// the function.
if (IndirectBranch) {
EmitBlock(IndirectBranch->getParent());
Builder.ClearInsertionPoint();
}
#endif
// Remove the AllocaInsertPt instruction, which is just a convenience for us.
llvm::Instruction *Ptr = AllocaInsertPt;
AllocaInsertPt = 0;
Ptr->eraseFromParent();
#ifdef USEINDIRECTBRANCH
// If someone took the address of a label but never did an indirect goto, we
// made a zero entry PHI node, which is illegal, zap it now.
if (IndirectBranch) {
llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress());
if (PN->getNumIncomingValues() == 0) {
PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType()));
PN->eraseFromParent();
}
}
#endif
}
void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
@@ -466,13 +493,26 @@ void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) {
TypeInfo.second/8));
}
#ifndef USEINDIRECTBRANCH
unsigned CodeGenFunction::GetIDForAddrOfLabel(const LabelStmt *L) {
// Use LabelIDs.size()+1 as the new ID if one hasn't been assigned.
unsigned &Entry = LabelIDs[L];
if (Entry) return Entry;
#else
llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelStmt *L) {
// Make sure that there is a block for the indirect goto.
if (IndirectBranch == 0)
GetIndirectGotoBlock();
#endif
#ifndef USEINDIRECTBRANCH
Entry = LabelIDs.size();
#else
llvm::BasicBlock *BB = getBasicBlockForLabel(L);
#endif
#ifndef USEINDIRECTBRANCH
// If this is the first "address taken" of a label and the indirect goto has
// already been seen, add this to it.
if (IndirectGotoSwitch) {
@@ -488,19 +528,42 @@ unsigned CodeGenFunction::GetIDForAddrOfLabel(const LabelStmt *L) {
}
return Entry;
#else
// Make sure the indirect branch includes all of the address-taken blocks.
IndirectBranch->addDestination(BB);
return llvm::BlockAddress::get(CurFn, BB);
#endif
}
llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() {
#ifndef USEINDIRECTBRANCH
// If we already made the switch stmt for indirect goto, return its block.
if (IndirectGotoSwitch) return IndirectGotoSwitch->getParent();
#else
// If we already made the indirect branch for indirect goto, return its block.
if (IndirectBranch) return IndirectBranch->getParent();
#endif
#ifndef USEINDIRECTBRANCH
EmitBlock(createBasicBlock("indirectgoto"));
#else
CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto"));
#endif
#ifndef USEINDIRECTBRANCH
const llvm::IntegerType *Int32Ty = llvm::Type::getInt32Ty(VMContext);
#else
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
#endif
// Create the PHI node that indirect gotos will add entries to.
#ifndef USEINDIRECTBRANCH
llvm::Value *DestVal = Builder.CreatePHI(Int32Ty, "indirect.goto.dest");
#else
llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, "indirect.goto.dest");
#endif
#ifndef USEINDIRECTBRANCH
// Create the switch instruction. For now, set the insert block to this block
// which will be fixed as labels are added.
IndirectGotoSwitch = Builder.CreateSwitch(DestVal, Builder.GetInsertBlock());
@@ -540,6 +603,11 @@ llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() {
}
return IndirectGotoSwitch->getParent();
#else
// Create the indirect branch instruction.
IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal);
return IndirectBranch->getParent();
#endif
}
llvm::Value *CodeGenFunction::GetVLASize(const VariableArrayType *VAT) {