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Reverting r85338 for now. It's causing a bootstrap failure on PPC darwin9. 

--- Reverse-merging r85338 into '.':
U    lib/CodeGen/SimpleRegisterCoalescing.cpp
U    lib/CodeGen/SimpleRegisterCoalescing.h

llvm-svn: 85454
This commit is contained in:
Bill Wendling 2009-10-29 00:22:16 +00:00
parent edc56ef41c
commit a8eceedb82
6 changed files with 309 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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

@ -186,7 +186,7 @@ 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 TargetLowering *tli, bool fast);
FunctionPass *createDwarfEHPass(const TargetLowering *tli);
/// createSjLjEHPass - This pass adapts exception handling code to use
/// the GCC-style builtin setjmp/longjmp (sjlj) to handling EH control flow.

13
llvm/include/llvm/IntrinsicInst.h
View File

@ -307,6 +307,19 @@ namespace llvm {
}
};
/// EHExceptionInst - This represents the llvm.eh.exception instruction.
///
struct EHExceptionInst : public IntrinsicInst {
// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const EHExceptionInst *) { return true; }
static inline bool classof(const IntrinsicInst *I) {
return I->getIntrinsicID() == Intrinsic::eh_exception;
}
static inline bool classof(const Value *V) {
return isa<IntrinsicInst>(V) && classof(cast<IntrinsicInst>(V));
}
};
/// EHSelectorInst - This represents the llvm.eh.selector instruction.
///
struct EHSelectorInst : public IntrinsicInst {

326
llvm/lib/CodeGen/DwarfEHPrepare.cpp
View File

@ -21,27 +21,41 @@
#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/IRBuilder.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");
STATISTIC(NumUnwindsLowered, "Number of unwind instructions lowered");
STATISTIC(NumExceptionValuesMoved, "Number of eh.exception calls moved");
STATISTIC(NumLonelyLandingPads, "Number of landing pads with no selector");
STATISTIC(NumLonelySelectors, "Number of lonely selectors lowered");
STATISTIC(NumLandingPadsSplit, "Number of landing pads split");
STATISTIC(NumSelectorsAdjusted, "Number of selector results adjusted");
STATISTIC(NumSelectorsSimplified, "Number of selectors truncated");
STATISTIC(NumStackTempsIntroduced, "Number of stack temporaries introduced");
STATISTIC(NumUnwindsLowered, "Number of unwind instructions lowered");
namespace {
class DwarfEHPrepare : public FunctionPass {
const TargetLowering *TLI;
bool CompileFast;
// The eh.exception intrinsic.
Function *ExceptionValueIntrinsic;
Function *ExceptionIntrinsic;
// The eh.selector intrinsic.
Function *SelectorIntrinsic;
// The eh.typeid.for intrinsic.
Function *TypeIdIntrinsic;
// _Unwind_Resume or the target equivalent.
Constant *RewindFunction;
// _Unwind_RaiseException.
Constant *UnwindFunction;
// Dominator info is used when turning stack temporaries into registers.
DominatorTree *DT;
DominanceFrontier *DF;
@ -49,6 +63,13 @@ namespace {
// The function we are running on.
Function *F;
// The current context.
LLVMContext *Context;
// The personality and catch-all value for this function.
Constant *Personality;
Constant *CatchAll;
// The landing pads for this function.
typedef SmallPtrSet<BasicBlock*, 8> BBSet;
BBSet LandingPads;
@ -58,7 +79,10 @@ namespace {
bool NormalizeLandingPads();
bool LowerUnwinds();
bool MoveSelectorCalls();
bool RectifySelectorCalls();
bool MoveExceptionValueCalls();
bool AddMissingSelectors();
bool FinishStackTemporaries();
bool PromoteStackTemporaries();
@ -75,22 +99,13 @@ namespace {
public:
static char ID; // Pass identification, replacement for typeid.
DwarfEHPrepare(const TargetLowering *tli, bool fast) :
FunctionPass(&ID), TLI(tli), CompileFast(fast),
ExceptionValueIntrinsic(0), RewindFunction(0) {}
DwarfEHPrepare(const TargetLowering *tli) :
FunctionPass(&ID), TLI(tli), ExceptionIntrinsic(0),
SelectorIntrinsic(0), TypeIdIntrinsic(0), RewindFunction(0),
UnwindFunction(0) {}
virtual bool runOnFunction(Function &Fn);
// getAnalysisUsage - We need dominance frontiers for memory promotion.
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
if (!CompileFast)
AU.addRequired<DominatorTree>();
AU.addPreserved<DominatorTree>();
if (!CompileFast)
AU.addRequired<DominanceFrontier>();
AU.addPreserved<DominanceFrontier>();
}
const char *getPassName() const {
return "Exception handling preparation";
}
@ -100,8 +115,8 @@ namespace {
char DwarfEHPrepare::ID = 0;
FunctionPass *llvm::createDwarfEHPass(const TargetLowering *tli, bool fast) {
return new DwarfEHPrepare(tli, fast);
FunctionPass *llvm::createDwarfEHPass(const TargetLowering *tli) {
return new DwarfEHPrepare(tli);
}
/// NormalizeLandingPads - Normalize and discover landing pads, noting them
@ -144,7 +159,7 @@ bool DwarfEHPrepare::NormalizeLandingPads() {
// edges to a new basic block which falls through into this one.
// Create the new basic block.
BasicBlock *NewBB = BasicBlock::Create(F->getContext(),
BasicBlock *NewBB = BasicBlock::Create(*Context,
LPad->getName() + "_unwind_edge");
// Insert it into the function right before the original landing pad.
@ -233,17 +248,14 @@ bool DwarfEHPrepare::LowerUnwinds() {
// Find the rewind function if we didn't already.
if (!RewindFunction) {
LLVMContext &Ctx = UnwindInsts[0]->getContext();
std::vector<const Type*>
Params(1, Type::getInt8PtrTy(Ctx));
FunctionType *FTy = FunctionType::get(Type::getVoidTy(Ctx),
Params(1, Type::getInt8PtrTy(*Context));
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Context),
Params, false);
const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
}
bool Changed = false;
for (SmallVectorImpl<TerminatorInst*>::iterator
I = UnwindInsts.begin(), E = UnwindInsts.end(); I != E; ++I) {
TerminatorInst *TI = *I;
@ -257,11 +269,244 @@ bool DwarfEHPrepare::LowerUnwinds() {
"", TI);
CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
// ...followed by an UnreachableInst.
new UnreachableInst(TI->getContext(), TI);
new UnreachableInst(*Context, TI);
// Nuke the unwind instruction.
TI->eraseFromParent();
++NumUnwindsLowered;
}
return true;
}
/// MoveSelectorCalls - Make sure that every call to eh.selector occurs in its
/// own landing pad, the landing pad corresponding to the exception object.
bool DwarfEHPrepare::MoveSelectorCalls() {
// If the eh.selector intrinsic is not declared in the module then there is
// nothing to do. Speed up compilation by checking for this common case.
if (!F->getParent()->getFunction(Intrinsic::getName(Intrinsic::eh_selector)))
return false;
// TODO: There is a lot of room for optimization here.
bool Changed = false;
BasicBlock *UnrBB = 0;
for (Function::iterator BB = F->begin(); BB != F->end(); ++BB) {
// If this basic block is not a landing pad then synthesize a landing pad
// for every selector in it.
bool SynthesizeLandingPad = !LandingPads.count(BB);
for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; ++II) {
EHSelectorInst *SI = dyn_cast<EHSelectorInst>(II);
// Only interested in eh.selector calls.
if (!SI)
continue;
// Note the personality and catch-all for later use.
Personality = cast<Constant>(SI->getOperand(2));
CatchAll = cast<Constant>(SI->getOperand(SI->getNumOperands() - 1)
->stripPointerCasts());
// The exception object.
Value *Exception = SI->getOperand(1);
if (!SynthesizeLandingPad) {
// Did the exception come from unwinding to this landing pad or another?
// If it comes from a different landing pad then we need to synthesize a
// new landing pad for the selector.
EHExceptionInst *EI = dyn_cast<EHExceptionInst>(Exception);
SynthesizeLandingPad = !EI || EI->getParent() != BB;
}
if (!SynthesizeLandingPad) {
// This is the first selector in this landing pad, and it is the landing
// pad corresponding to the exception object. No need to do anything to
// this selector, but any subsequent selectors in this landing pad will
// need their own invoke in order to make them independent of this one.
SynthesizeLandingPad = true;
continue;
}
// Rethrow the exception and catch it again, generating a landing pad for
// this selector to live in.
// Find _Unwind_RaiseException if we didn't already.
if (!UnwindFunction) {
std::vector<const Type*> ArgTys(1, Type::getInt8PtrTy(*Context));
const FunctionType *FTy =
FunctionType::get(Type::getInt32Ty(*Context), ArgTys, true);
const char *Name = "_Unwind_RaiseException";
UnwindFunction = F->getParent()->getOrInsertFunction(Name, FTy);
}
// Create a basic block containing only an unreachable instruction if we
// didn't already.
if (!UnrBB) {
UnrBB = BasicBlock::Create(*Context, "unreachable", F);
new UnreachableInst(*Context, UnrBB);
}
// Split the basic block before the selector.
BasicBlock *NewBB = SplitBlock(BB, SI, this);
// Replace the terminator with an invoke of _Unwind_RaiseException.
BB->getTerminator()->eraseFromParent();
InvokeInst::Create(UnwindFunction, UnrBB, NewBB, &Exception,
1 + &Exception, "", BB);
// The split off basic block is now a landing pad.
LandingPads.insert(NewBB);
// Replace the exception argument in the selector call with a call to
// eh.exception. This is not really necessary but it makes things more
// regular.
Exception = CreateExceptionValueCall(NewBB);
SI->setOperand(1, Exception);
++NumLonelySelectors;
Changed = true;
// All instructions still in the original basic block have been scanned.
// Move on to the next basic block.
break;
}
}
return Changed;
}
/// RectifySelectorCalls - Remove useless catch-all clauses from the ends of
/// selectors, or correct the selector result for the presence of the catch-all
/// if it is really needed.
bool DwarfEHPrepare::RectifySelectorCalls() {
// If the eh.selector intrinsic is not declared in the module then there is
// nothing to do. Speed up compilation by checking for this common case.
if (!F->getParent()->getFunction(Intrinsic::getName(Intrinsic::eh_selector)))
return false;
bool Changed = false;
for (BBSet::iterator I = LandingPads.begin(), E = LandingPads.end(); I != E;
++I)
for (BasicBlock::iterator II = (*I)->begin(), IE = (*I)->end(); II != IE; )
if (EHSelectorInst *SI = dyn_cast<EHSelectorInst>(II++)) {
// Found a call to eh.selector. Check whether it has a catch-all in the
// middle.
unsigned LastIndex = 0;
for (unsigned i = 3, e = SI->getNumOperands() - 1; i < e; ++i) {
Value *V = SI->getOperand(i);
if (V->stripPointerCasts() == CatchAll) {
// A catch-all. The catch-all at the end was not needed.
LastIndex = i;
break;
} else if (ConstantInt *FilterLength = dyn_cast<ConstantInt>(V)) {
// A cleanup or a filter.
unsigned Length = FilterLength->getZExtValue();
if (Length == 0)
// A cleanup - skip it.
continue;
if (Length == 1) {
// A catch-all filter. Drop everything that follows.
LastIndex = i;
break;
}
// A filter, skip over the typeinfos.
i += Length - 1;
}
}
if (LastIndex) {
// Drop the pointless catch-all from the end. In fact drop everything
// after LastIndex as an optimization.
SmallVector<Value*, 16> Args;
Args.reserve(LastIndex);
for (unsigned i = 1; i <= LastIndex; ++i)
Args.push_back(SI->getOperand(i));
CallInst *CI = CallInst::Create(SI->getOperand(0), Args.begin(),
Args.end(), "", SI);
CI->takeName(SI);
SI->replaceAllUsesWith(CI);
SI->eraseFromParent();
++NumSelectorsSimplified;
} else if (!isa<ConstantInt>(CatchAll) && // Not a cleanup.
!SI->use_empty()) {
// Correct the selector value to return zero if the catch-all matches.
Constant *Zero = ConstantInt::getNullValue(Type::getInt32Ty(*Context));
// Create the new selector value, with placeholders instead of the
// real operands and make everyone use it. The reason for this round
// about approach is that the computation of the new value makes use
// of the old value, so we can't just compute it then do RAUW.
SelectInst *S = SelectInst::Create(ConstantInt::getFalse(*Context),
Zero, Zero, "", II);
SI->replaceAllUsesWith(S);
// Now calculate the operands of the select.
IRBuilder<> Builder(*I, S);
// Find the eh.typeid.for intrinsic if we didn't already.
if (!TypeIdIntrinsic)
TypeIdIntrinsic = Intrinsic::getDeclaration(F->getParent(),
Intrinsic::eh_typeid_for);
// Obtain the id of the catch-all.
Value *CatchAllId = Builder.CreateCall(TypeIdIntrinsic,
ConstantExpr::getBitCast(CatchAll, Type::getInt8PtrTy(*Context)));
// Compare it with the original selector result. If it matched then
// the selector result is zero, otherwise it is the original selector.
Value *MatchesCatchAll = Builder.CreateICmpEQ(SI, CatchAllId);
S->setOperand(0, MatchesCatchAll);
S->setOperand(2, SI);
++NumSelectorsAdjusted;
}
Changed = true;
break;
}
return Changed;
}
/// Make sure every landing pad has a selector in it.
bool DwarfEHPrepare::AddMissingSelectors() {
if (!Personality)
// We only know how to codegen invokes if there is a personality.
// FIXME: This results in wrong code.
return false;
bool Changed = false;
for (BBSet::iterator I = LandingPads.begin(), E = LandingPads.end(); I != E;
++I) {
bool FoundSelector = false;
// Check whether the landing pad already contains a call to eh.selector.
for (BasicBlock::iterator II = (*I)->begin(), IE = (*I)->end(); II != IE;
++II)
if (isa<EHSelectorInst>(II)) {
FoundSelector = true;
break;
}
if (FoundSelector)
continue;
// Find the eh.selector intrinsic if we didn't already.
if (!SelectorIntrinsic)
SelectorIntrinsic = Intrinsic::getDeclaration(F->getParent(),
Intrinsic::eh_selector);
// Get the exception object.
Instruction *Exception = CreateExceptionValueCall(*I);
Value *Args[3] = { Exception, Personality, CatchAll };
CallInst *Selector = CallInst::Create(SelectorIntrinsic, Args, Args + 3);
Selector->insertAfter(Exception);
++NumLonelyLandingPads;
Changed = true;
}
@ -275,7 +520,7 @@ bool DwarfEHPrepare::LowerUnwinds() {
bool DwarfEHPrepare::MoveExceptionValueCalls() {
// If the eh.exception intrinsic is not declared in the module then there is
// nothing to do. Speed up compilation by checking for this common case.
if (!ExceptionValueIntrinsic &&
if (!ExceptionIntrinsic &&
!F->getParent()->getFunction(Intrinsic::getName(Intrinsic::eh_exception)))
return false;
@ -332,7 +577,7 @@ 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, ExceptionValueVar->getContext());
PromoteMemToReg(Allocas, *DT, *DF, *Context);
return true;
}
return false;
@ -350,12 +595,12 @@ Instruction *DwarfEHPrepare::CreateExceptionValueCall(BasicBlock *BB) {
return Start;
// Find the eh.exception intrinsic if we didn't already.
if (!ExceptionValueIntrinsic)
ExceptionValueIntrinsic = Intrinsic::getDeclaration(F->getParent(),
if (!ExceptionIntrinsic)
ExceptionIntrinsic = Intrinsic::getDeclaration(F->getParent(),
Intrinsic::eh_exception);
// Create the call.
return CallInst::Create(ExceptionValueIntrinsic, "eh.value.call", Start);
return CallInst::Create(ExceptionIntrinsic, "eh.value.call", Start);
}
/// CreateValueLoad - Insert a load of the exception value stack variable
@ -373,7 +618,7 @@ Instruction *DwarfEHPrepare::CreateValueLoad(BasicBlock *BB) {
// Create the temporary if we didn't already.
if (!ExceptionValueVar) {
ExceptionValueVar = new AllocaInst(PointerType::getUnqual(
Type::getInt8Ty(BB->getContext())), "eh.value", F->begin()->begin());
Type::getInt8Ty(*Context)), "eh.value", F->begin()->begin());
++NumStackTempsIntroduced;
}
@ -388,6 +633,9 @@ bool DwarfEHPrepare::runOnFunction(Function &Fn) {
DT = getAnalysisIfAvailable<DominatorTree>();
DF = getAnalysisIfAvailable<DominanceFrontier>();
ExceptionValueVar = 0;
Personality = 0;
CatchAll = 0;
Context = &Fn.getContext();
F = &Fn;
// Ensure that only unwind edges end at landing pads (a landing pad is a
@ -397,7 +645,15 @@ bool DwarfEHPrepare::runOnFunction(Function &Fn) {
// Turn unwind instructions into libcalls.
Changed |= LowerUnwinds();
// TODO: Move eh.selector calls to landing pads and combine them.
// Make sure that every call to eh.selector occurs in its own landing pad.
Changed |= MoveSelectorCalls();
// Remove useless catch-all clauses from the ends of selectors, or correct the
// selector result for the presence of the catch-all if it is really needed.
Changed |= RectifySelectorCalls();
// Make sure every landing pad has a selector in it.
Changed |= AddMissingSelectors();
// Move eh.exception calls to landing pads.
Changed |= MoveExceptionValueCalls();
@ -406,8 +662,8 @@ bool DwarfEHPrepare::runOnFunction(Function &Fn) {
Changed |= FinishStackTemporaries();
// Turn any stack temporaries into registers if possible.
if (!CompileFast)
Changed |= PromoteStackTemporaries();
//TODO if (!CompileFast)
//TODO Changed |= PromoteStackTemporaries();
LandingPads.clear();

4
llvm/lib/CodeGen/LLVMTargetMachine.cpp
View File

@ -239,11 +239,11 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
{
case ExceptionHandling::SjLj:
// SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
PM.add(createDwarfEHPass(getTargetLowering()));
PM.add(createSjLjEHPass(getTargetLowering()));
break;
case ExceptionHandling::Dwarf:
PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
PM.add(createDwarfEHPass(getTargetLowering()));
break;
case ExceptionHandling::None:
PM.add(createLowerInvokePass(getTargetLowering()));

19
llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
View File

@ -1861,21 +1861,6 @@ bool SimpleRegisterCoalescing::RangeIsDefinedByCopyFromReg(LiveInterval &li,
return false;
}
/// ValueLiveAt - Return true if the LiveRange pointed to by the given
/// iterator, or any subsequent range with the same value number,
/// is live at the given point.
bool SimpleRegisterCoalescing::ValueLiveAt(LiveInterval::iterator LRItr,
LiveIndex defPoint) const {
for (const VNInfo *valno = LRItr->valno; LRItr->valno == valno; ++LRItr) {
if (LRItr->contains(defPoint))
return true;
}
return false;
}
/// SimpleJoin - Attempt to joint the specified interval into this one. The
/// caller of this method must guarantee that the RHS only contains a single
/// value number and that the RHS is not defined by a copy from this
@ -1922,7 +1907,7 @@ bool SimpleRegisterCoalescing::SimpleJoin(LiveInterval &LHS, LiveInterval &RHS){
if (!RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg))
return false; // Nope, bail out.
if (ValueLiveAt(LHSIt, RHSIt->valno->def))
if (LHSIt->contains(RHSIt->valno->def))
// Here is an interesting situation:
// BB1:
// vr1025 = copy vr1024
@ -1960,7 +1945,7 @@ bool SimpleRegisterCoalescing::SimpleJoin(LiveInterval &LHS, LiveInterval &RHS){
// Otherwise, if this is a copy from the RHS, mark it as being merged
// in.
if (RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg)) {
if (ValueLiveAt(LHSIt, RHSIt->valno->def))
if (LHSIt->contains(RHSIt->valno->def))
// Here is an interesting situation:
// BB1:
// vr1025 = copy vr1024

5
llvm/lib/CodeGen/SimpleRegisterCoalescing.h
View File

@ -201,11 +201,6 @@ namespace llvm {
bool CanJoinInsertSubRegToPhysReg(unsigned DstReg, unsigned SrcReg,
unsigned SubIdx, unsigned &RealDstReg);
/// ValueLiveAt - Return true if the LiveRange pointed to by the given
/// iterator, or any subsequent range with the same value number,
/// is live at the given point.
bool ValueLiveAt(LiveInterval::iterator LRItr, LiveIndex defPoint) const;
/// RangeIsDefinedByCopyFromReg - Return true if the specified live range of
/// the specified live interval is defined by a copy from the specified
/// register.