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Stop using the dom frontier in DwarfEHPrepare by not promoting alloca's 

any more.  I plan to reimplement alloca promotion using SSAUpdater later.
It looks like Bill's URoR logic really always needs domtree, so the pass
now always asks for domtree info.

llvm-svn: 112597
This commit is contained in:
Duncan Sands 2010-08-31 09:05:06 +00:00
parent 68984ede5c
commit bb8a3f9f6d
3 changed files with 11 additions and 88 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
llvm/include/llvm/CodeGen/Passes.h
View File

@ -192,7 +192,7 @@ namespace llvm {
/// createDwarfEHPass - This pass mulches exception handling code into a form
/// adapted to code generation. Required if using dwarf exception handling.
FunctionPass *createDwarfEHPass(const TargetMachine *tm, bool fast);
FunctionPass *createDwarfEHPass(const TargetMachine *tm);
/// createSjLjEHPass - This pass adapts exception handling code to use
/// the GCC-style builtin setjmp/longjmp (sjlj) to handling EH control flow.

95
llvm/lib/CodeGen/DwarfEHPrepare.cpp
View File

@ -25,7 +25,6 @@
#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/PromoteMemToReg.h"
using namespace llvm;
STATISTIC(NumLandingPadsSplit, "Number of landing pads split");
@ -37,7 +36,6 @@ namespace {
class DwarfEHPrepare : public FunctionPass {
const TargetMachine *TM;
const TargetLowering *TLI;
bool CompileFast;
// The eh.exception intrinsic.
Function *ExceptionValueIntrinsic;
@ -54,9 +52,8 @@ namespace {
// _Unwind_Resume or the target equivalent.
Constant *RewindFunction;
// Dominator info is used when turning stack temporaries into registers.
// We both use and preserve dominator info.
DominatorTree *DT;
DominanceFrontier *DF;
// The function we are running on.
Function *F;
@ -72,7 +69,6 @@ namespace {
bool LowerUnwinds();
bool MoveExceptionValueCalls();
bool FinishStackTemporaries();
bool PromoteStackTemporaries();
Instruction *CreateExceptionValueCall(BasicBlock *BB);
Instruction *CreateValueLoad(BasicBlock *BB);
@ -112,49 +108,10 @@ namespace {
bool FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
SmallPtrSet<IntrinsicInst*, 8> &SelCalls);
/// PromoteStoreInst - Perform Mem2Reg on a StoreInst.
bool PromoteStoreInst(StoreInst *SI) {
if (!SI || !DT || !DF) return false;
AllocaInst *AI = dyn_cast<AllocaInst>(SI->getOperand(1));
if (!AI || !isAllocaPromotable(AI)) return false;
// Turn the alloca into a register.
std::vector<AllocaInst*> Allocas(1, AI);
PromoteMemToReg(Allocas, *DT, *DF);
return true;
}
/// PromoteEHPtrStore - Promote the storing of an EH pointer into a
/// register. This should get rid of the store and subsequent loads.
bool PromoteEHPtrStore(IntrinsicInst *II) {
if (!DT || !DF) return false;
bool Changed = false;
StoreInst *SI;
while (1) {
SI = 0;
for (Value::use_iterator
I = II->use_begin(), E = II->use_end(); I != E; ++I) {
SI = dyn_cast<StoreInst>(*I);
if (SI) break;
}
if (!PromoteStoreInst(SI))
break;
Changed = true;
}
return Changed;
}
public:
static char ID; // Pass identification, replacement for typeid.
DwarfEHPrepare(const TargetMachine *tm, bool fast) :
DwarfEHPrepare(const TargetMachine *tm) :
FunctionPass(ID), TM(tm), TLI(TM->getTargetLowering()),
CompileFast(fast),
ExceptionValueIntrinsic(0), SelectorIntrinsic(0),
URoR(0), EHCatchAllValue(0), RewindFunction(0) {}
@ -162,12 +119,8 @@ namespace {
// getAnalysisUsage - We need dominance frontiers for memory promotion.
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
if (!CompileFast)
AU.addRequired<DominatorTree>();
AU.addRequired<DominatorTree>();
AU.addPreserved<DominatorTree>();
if (!CompileFast)
AU.addRequired<DominanceFrontier>();
AU.addPreserved<DominanceFrontier>();
}
const char *getPassName() const {
@ -179,8 +132,8 @@ namespace {
char DwarfEHPrepare::ID = 0;
FunctionPass *llvm::createDwarfEHPass(const TargetMachine *tm, bool fast) {
return new DwarfEHPrepare(tm, fast);
FunctionPass *llvm::createDwarfEHPass(const TargetMachine *tm) {
return new DwarfEHPrepare(tm);
}
/// HasCatchAllInSelector - Return true if the intrinsic instruction has a
@ -261,7 +214,6 @@ DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
SmallPtrSet<PHINode*, 32> SeenPHIs;
bool Changed = false;
restart:
for (Value::use_iterator
I = Inst->use_begin(), E = Inst->use_end(); I != E; ++I) {
Instruction *II = dyn_cast<Instruction>(*I);
@ -275,11 +227,6 @@ DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
URoRInvoke = true;
} else if (CastInst *CI = dyn_cast<CastInst>(II)) {
Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls);
} else if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
if (!PromoteStoreInst(SI)) continue;
Changed = true;
SeenPHIs.clear();
goto restart; // Uses may have changed, restart loop.
} else if (PHINode *PN = dyn_cast<PHINode>(II)) {
if (SeenPHIs.insert(PN))
// Don't process a PHI node more than once.
@ -311,10 +258,6 @@ bool DwarfEHPrepare::HandleURoRInvokes() {
SmallPtrSet<IntrinsicInst*, 32> CatchAllSels;
FindAllCleanupSelectors(Sels, CatchAllSels);
if (!DT)
// We require DominatorTree information.
return CleanupSelectors(CatchAllSels);
if (!URoR) {
URoR = F->getParent()->getFunction("_Unwind_Resume_or_Rethrow");
if (!URoR) return CleanupSelectors(CatchAllSels);
@ -356,8 +299,6 @@ bool DwarfEHPrepare::HandleURoRInvokes() {
IntrinsicInst *EHPtr = dyn_cast<IntrinsicInst>(*I);
if (!EHPtr || EHPtr->getParent()->getParent() != F) continue;
Changed |= PromoteEHPtrStore(EHPtr);
bool URoRInvoke = false;
SmallPtrSet<IntrinsicInst*, 8> SelCalls;
Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls);
@ -525,11 +466,8 @@ bool DwarfEHPrepare::NormalizeLandingPads() {
// Add a fallthrough from NewBB to the original landing pad.
BranchInst::Create(LPad, NewBB);
// Now update DominatorTree and DominanceFrontier analysis information.
if (DT)
DT->splitBlock(NewBB);
if (DF)
DF->splitBlock(NewBB);
// Now update DominatorTree analysis information.
DT->splitBlock(NewBB);
// Remember the newly constructed landing pad. The original landing pad
// LPad is no longer a landing pad now that all unwind edges have been
@ -652,18 +590,6 @@ bool DwarfEHPrepare::FinishStackTemporaries() {
return Changed;
}
/// PromoteStackTemporaries - Turn any stack temporaries we introduced into
/// registers if possible.
bool DwarfEHPrepare::PromoteStackTemporaries() {
if (ExceptionValueVar && DT && DF && isAllocaPromotable(ExceptionValueVar)) {
// Turn the exception temporary into registers and phi nodes if possible.
std::vector<AllocaInst*> Allocas(1, ExceptionValueVar);
PromoteMemToReg(Allocas, *DT, *DF);
return true;
}
return false;
}
/// CreateExceptionValueCall - Insert a call to the eh.exception intrinsic at
/// the start of the basic block (unless there already is one, in which case
/// the existing call is returned).
@ -711,8 +637,7 @@ bool DwarfEHPrepare::runOnFunction(Function &Fn) {
bool Changed = false;
// Initialize internal state.
DT = getAnalysisIfAvailable<DominatorTree>();
DF = getAnalysisIfAvailable<DominanceFrontier>();
DT = &getAnalysis<DominatorTree>();
ExceptionValueVar = 0;
F = &Fn;
@ -731,9 +656,7 @@ bool DwarfEHPrepare::runOnFunction(Function &Fn) {
// Initialize any stack temporaries we introduced.
Changed |= FinishStackTemporaries();
// Turn any stack temporaries into registers if possible.
if (!CompileFast)
Changed |= PromoteStackTemporaries();
// TODO: Turn any stack temporaries into registers if possible.
Changed |= HandleURoRInvokes();

2
llvm/lib/CodeGen/LLVMTargetMachine.cpp
View File

@ -289,7 +289,7 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
PM.add(createSjLjEHPass(getTargetLowering()));
// FALLTHROUGH
case ExceptionHandling::Dwarf:
PM.add(createDwarfEHPass(this, OptLevel==CodeGenOpt::None));
PM.add(createDwarfEHPass(this));
break;
case ExceptionHandling::None:
PM.add(createLowerInvokePass(getTargetLowering()));