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-rw-r--r--lib/CodeGen/DwarfEHPrepare.cpp162
-rw-r--r--lib/Transforms/Scalar/GVN.cpp2
-rw-r--r--lib/Transforms/Scalar/JumpThreading.cpp4
-rw-r--r--lib/Transforms/Scalar/LICM.cpp4
-rw-r--r--lib/Transforms/Scalar/LoopRotation.cpp2
-rw-r--r--lib/Transforms/Utils/LCSSA.cpp2
-rw-r--r--lib/Transforms/Utils/SSAUpdater.cpp24
7 files changed, 102 insertions, 98 deletions
diff --git a/lib/CodeGen/DwarfEHPrepare.cpp b/lib/CodeGen/DwarfEHPrepare.cpp
index 550fd3e..2522d0b 100644
--- a/lib/CodeGen/DwarfEHPrepare.cpp
+++ b/lib/CodeGen/DwarfEHPrepare.cpp
@@ -25,12 +25,12 @@
#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/SSAUpdater.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(NumStackTempsIntroduced, "Number of stack temporaries introduced");
namespace {
class DwarfEHPrepare : public FunctionPass {
@@ -62,11 +62,24 @@ namespace {
typedef SmallPtrSet<BasicBlock*, 8> BBSet;
BBSet LandingPads;
+ // Stack temporary used to hold eh.exception values.
+ AllocaInst *ExceptionValueVar;
+
bool NormalizeLandingPads();
bool LowerUnwinds();
bool MoveExceptionValueCalls();
+ bool FinishStackTemporaries();
Instruction *CreateExceptionValueCall(BasicBlock *BB);
+ Instruction *CreateValueLoad(BasicBlock *BB);
+
+ /// CreateReadOfExceptionValue - Return the result of the eh.exception
+ /// intrinsic by calling the intrinsic if in a landing pad, or loading it
+ /// from the exception value variable otherwise.
+ Instruction *CreateReadOfExceptionValue(BasicBlock *BB) {
+ return LandingPads.count(BB) ?
+ CreateExceptionValueCall(BB) : CreateValueLoad(BB);
+ }
/// CleanupSelectors - Any remaining eh.selector intrinsic calls which still
/// use the "llvm.eh.catch.all.value" call need to convert to using its
@@ -104,7 +117,7 @@ namespace {
virtual bool runOnFunction(Function &Fn);
- // getAnalysisUsage - We need the dominator tree for handling URoR.
+ // getAnalysisUsage - We need dominance frontiers for memory promotion.
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<DominatorTree>();
AU.addPreserved<DominatorTree>();
@@ -504,7 +517,7 @@ bool DwarfEHPrepare::LowerUnwinds() {
// Create the call...
CallInst *CI = CallInst::Create(RewindFunction,
- CreateExceptionValueCall(TI->getParent()),
+ CreateReadOfExceptionValue(TI->getParent()),
"", TI);
CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
// ...followed by an UnreachableInst.
@@ -520,11 +533,9 @@ bool DwarfEHPrepare::LowerUnwinds() {
}
/// MoveExceptionValueCalls - Ensure that eh.exception is only ever called from
-/// landing pads by replacing calls outside of landing pads with direct use of
-/// a register holding the appropriate value; this requires adding calls inside
-/// all landing pads to initialize the register. Also, move eh.exception calls
-/// inside landing pads to the start of the landing pad (optional, but may make
-/// things simpler for later passes).
+/// landing pads by replacing calls outside of landing pads with loads from a
+/// stack temporary. Move eh.exception calls inside landing pads to the start
+/// of the landing pad (optional, but may make things simpler for later passes).
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.
@@ -534,87 +545,49 @@ bool DwarfEHPrepare::MoveExceptionValueCalls() {
bool Changed = false;
- // Move calls to eh.exception that are inside a landing pad to the start of
- // the landing pad.
- for (BBSet::const_iterator LI = LandingPads.begin(), LE = LandingPads.end();
- LI != LE; ++LI) {
- BasicBlock *LP = *LI;
- for (BasicBlock::iterator II = LP->getFirstNonPHIOrDbg(), IE = LP->end();
- II != IE;)
- if (EHExceptionInst *EI = dyn_cast<EHExceptionInst>(II++)) {
- // Found a call to eh.exception.
- if (!EI->use_empty()) {
- // If there is already a call to eh.exception at the start of the
- // landing pad, then get hold of it; otherwise create such a call.
- Value *CallAtStart = CreateExceptionValueCall(LP);
-
- // If the call was at the start of a landing pad then leave it alone.
- if (EI == CallAtStart)
- continue;
- EI->replaceAllUsesWith(CallAtStart);
+ for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+ for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E;)
+ if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(II++))
+ if (CI->getIntrinsicID() == Intrinsic::eh_exception) {
+ if (!CI->use_empty()) {
+ Value *ExceptionValue = CreateReadOfExceptionValue(BB);
+ if (CI == ExceptionValue) {
+ // The call was at the start of a landing pad - leave it alone.
+ assert(LandingPads.count(BB) &&
+ "Created eh.exception call outside landing pad!");
+ continue;
+ }
+ CI->replaceAllUsesWith(ExceptionValue);
+ }
+ CI->eraseFromParent();
+ ++NumExceptionValuesMoved;
+ Changed = true;
}
- EI->eraseFromParent();
- ++NumExceptionValuesMoved;
- Changed = true;
- }
}
- // Look for calls to eh.exception that are not in a landing pad. If one is
- // found, then a register that holds the exception value will be created in
- // each landing pad, and the SSAUpdater will be used to compute the values
- // returned by eh.exception calls outside of landing pads.
- SSAUpdater SSA;
-
- // Remember where we found the eh.exception call, to avoid rescanning earlier
- // basic blocks which we already know contain no eh.exception calls.
- bool FoundCallOutsideLandingPad = false;
- Function::iterator BB = F->begin();
- for (Function::iterator BE = F->end(); BB != BE; ++BB) {
- // Skip over landing pads.
- if (LandingPads.count(BB))
- continue;
-
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
- II != IE; ++II)
- if (isa<EHExceptionInst>(II)) {
- SSA.Initialize(II->getType(), II->getName());
- FoundCallOutsideLandingPad = true;
- break;
- }
+ return Changed;
+}
- if (FoundCallOutsideLandingPad)
- break;
- }
+/// FinishStackTemporaries - If we introduced a stack variable to hold the
+/// exception value then initialize it in each landing pad.
+bool DwarfEHPrepare::FinishStackTemporaries() {
+ if (!ExceptionValueVar)
+ // Nothing to do.
+ return false;
- // If all calls to eh.exception are in landing pads then we are done.
- if (!FoundCallOutsideLandingPad)
- return Changed;
+ bool Changed = false;
- // Add a call to eh.exception at the start of each landing pad, and tell the
- // SSAUpdater that this is the value produced by the landing pad.
+ // Make sure that there is a store of the exception value at the start of
+ // each landing pad.
for (BBSet::iterator LI = LandingPads.begin(), LE = LandingPads.end();
- LI != LE; ++LI)
- SSA.AddAvailableValue(*LI, CreateExceptionValueCall(*LI));
-
- // Now turn all calls to eh.exception that are not in a landing pad into a use
- // of the appropriate register.
- for (Function::iterator BE = F->end(); BB != BE; ++BB) {
- // Skip over landing pads.
- if (LandingPads.count(BB))
- continue;
-
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
- II != IE;)
- if (EHExceptionInst *EI = dyn_cast<EHExceptionInst>(II++)) {
- // Found a call to eh.exception, replace it with the value from any
- // upstream landing pad(s).
- EI->replaceAllUsesWith(SSA.GetValueAtEndOfBlock(BB));
- EI->eraseFromParent();
- ++NumExceptionValuesMoved;
- }
+ LI != LE; ++LI) {
+ Instruction *ExceptionValue = CreateReadOfExceptionValue(*LI);
+ Instruction *Store = new StoreInst(ExceptionValue, ExceptionValueVar);
+ Store->insertAfter(ExceptionValue);
+ Changed = true;
}
- return true;
+ return Changed;
}
/// CreateExceptionValueCall - Insert a call to the eh.exception intrinsic at
@@ -637,11 +610,35 @@ Instruction *DwarfEHPrepare::CreateExceptionValueCall(BasicBlock *BB) {
return CallInst::Create(ExceptionValueIntrinsic, "eh.value.call", Start);
}
+/// CreateValueLoad - Insert a load of the exception value stack variable
+/// (creating it if necessary) at the start of the basic block (unless
+/// there already is a load, in which case the existing load is returned).
+Instruction *DwarfEHPrepare::CreateValueLoad(BasicBlock *BB) {
+ Instruction *Start = BB->getFirstNonPHIOrDbg();
+ // Is this a load of the exception temporary?
+ if (ExceptionValueVar)
+ if (LoadInst* LI = dyn_cast<LoadInst>(Start))
+ if (LI->getPointerOperand() == ExceptionValueVar)
+ // Reuse the existing load.
+ return Start;
+
+ // Create the temporary if we didn't already.
+ if (!ExceptionValueVar) {
+ ExceptionValueVar = new AllocaInst(PointerType::getUnqual(
+ Type::getInt8Ty(BB->getContext())), "eh.value", F->begin()->begin());
+ ++NumStackTempsIntroduced;
+ }
+
+ // Load the value.
+ return new LoadInst(ExceptionValueVar, "eh.value.load", Start);
+}
+
bool DwarfEHPrepare::runOnFunction(Function &Fn) {
bool Changed = false;
// Initialize internal state.
DT = &getAnalysis<DominatorTree>();
+ ExceptionValueVar = 0;
F = &Fn;
// Ensure that only unwind edges end at landing pads (a landing pad is a
@@ -656,6 +653,11 @@ bool DwarfEHPrepare::runOnFunction(Function &Fn) {
// Move eh.exception calls to landing pads.
Changed |= MoveExceptionValueCalls();
+ // Initialize any stack temporaries we introduced.
+ Changed |= FinishStackTemporaries();
+
+ // TODO: Turn any stack temporaries into registers if possible.
+
Changed |= HandleURoRInvokes();
LandingPads.clear();
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index c62ce1f..e9cb52e 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -1310,7 +1310,7 @@ static Value *ConstructSSAForLoadSet(LoadInst *LI,
// Otherwise, we have to construct SSA form.
SmallVector<PHINode*, 8> NewPHIs;
SSAUpdater SSAUpdate(&NewPHIs);
- SSAUpdate.Initialize(LI->getType(), LI->getName());
+ SSAUpdate.Initialize(LI);
const Type *LoadTy = LI->getType();
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 5f35067..abf9886 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -1526,7 +1526,7 @@ bool JumpThreading::ThreadEdge(BasicBlock *BB,
// We found a use of I outside of BB. Rename all uses of I that are outside
// its block to be uses of the appropriate PHI node etc. See ValuesInBlocks
// with the two values we know.
- SSAUpdate.Initialize(I->getType(), I->getName());
+ SSAUpdate.Initialize(I);
SSAUpdate.AddAvailableValue(BB, I);
SSAUpdate.AddAvailableValue(NewBB, ValueMapping[I]);
@@ -1681,7 +1681,7 @@ bool JumpThreading::DuplicateCondBranchOnPHIIntoPred(BasicBlock *BB,
// We found a use of I outside of BB. Rename all uses of I that are outside
// its block to be uses of the appropriate PHI node etc. See ValuesInBlocks
// with the two values we know.
- SSAUpdate.Initialize(I->getType(), I->getName());
+ SSAUpdate.Initialize(I);
SSAUpdate.AddAvailableValue(BB, I);
SSAUpdate.AddAvailableValue(PredBB, ValueMapping[I]);
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp
index 85ed358..fa71ab5 100644
--- a/lib/Transforms/Scalar/LICM.cpp
+++ b/lib/Transforms/Scalar/LICM.cpp
@@ -526,7 +526,7 @@ void LICM::sink(Instruction &I) {
SSAUpdater SSA(&NewPHIs);
if (!I.use_empty())
- SSA.Initialize(I.getType(), I.getName());
+ SSA.Initialize(&I);
// Insert a copy of the instruction in each exit block of the loop that is
// dominated by the instruction. Each exit block is known to only be in the
@@ -728,7 +728,7 @@ void LICM::PromoteAliasSet(AliasSet &AS) {
SomeValue = LoopUses[0];
else
SomeValue = cast<StoreInst>(LoopUses[0])->getOperand(0);
- SSA.Initialize(SomeValue->getType(), SomeValue->getName());
+ SSA.Initialize(SomeValue);
// First step: bucket up uses of the pointers by the block they occur in.
// This is important because we have to handle multiple defs/uses in a block
diff --git a/lib/Transforms/Scalar/LoopRotation.cpp b/lib/Transforms/Scalar/LoopRotation.cpp
index 65acc1d..31957dd 100644
--- a/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/lib/Transforms/Scalar/LoopRotation.cpp
@@ -221,7 +221,7 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
// The value now exits in two versions: the initial value in the preheader
// and the loop "next" value in the original header.
- SSA.Initialize(OrigHeaderVal->getType(), OrigHeaderVal->getName());
+ SSA.Initialize(OrigHeaderVal);
SSA.AddAvailableValue(OrigHeader, OrigHeaderVal);
SSA.AddAvailableValue(OrigPreHeader, OrigPreHeaderVal);
diff --git a/lib/Transforms/Utils/LCSSA.cpp b/lib/Transforms/Utils/LCSSA.cpp
index 275b265..409b4bd 100644
--- a/lib/Transforms/Utils/LCSSA.cpp
+++ b/lib/Transforms/Utils/LCSSA.cpp
@@ -206,7 +206,7 @@ bool LCSSA::ProcessInstruction(Instruction *Inst,
DomTreeNode *DomNode = DT->getNode(DomBB);
SSAUpdater SSAUpdate;
- SSAUpdate.Initialize(Inst->getType(), Inst->getName());
+ SSAUpdate.Initialize(Inst);
// Insert the LCSSA phi's into all of the exit blocks dominated by the
// value, and add them to the Phi's map.
diff --git a/lib/Transforms/Utils/SSAUpdater.cpp b/lib/Transforms/Utils/SSAUpdater.cpp
index c855988..9dc2a1e 100644
--- a/lib/Transforms/Utils/SSAUpdater.cpp
+++ b/lib/Transforms/Utils/SSAUpdater.cpp
@@ -29,21 +29,20 @@ static AvailableValsTy &getAvailableVals(void *AV) {
}
SSAUpdater::SSAUpdater(SmallVectorImpl<PHINode*> *NewPHI)
- : AV(0), ProtoType(0), ProtoName(), InsertedPHIs(NewPHI) {}
+ : AV(0), PrototypeValue(0), InsertedPHIs(NewPHI) {}
SSAUpdater::~SSAUpdater() {
delete &getAvailableVals(AV);
}
/// Initialize - Reset this object to get ready for a new set of SSA
-/// updates with type 'Ty'. PHI nodes get a name based on 'Name'.
-void SSAUpdater::Initialize(const Type *Ty, StringRef Name) {
+/// updates. ProtoValue is the value used to name PHI nodes.
+void SSAUpdater::Initialize(Value *ProtoValue) {
if (AV == 0)
AV = new AvailableValsTy();
else
getAvailableVals(AV).clear();
- ProtoType = Ty;
- ProtoName = Name;
+ PrototypeValue = ProtoValue;
}
/// HasValueForBlock - Return true if the SSAUpdater already has a value for
@@ -55,8 +54,8 @@ bool SSAUpdater::HasValueForBlock(BasicBlock *BB) const {
/// AddAvailableValue - Indicate that a rewritten value is available in the
/// specified block with the specified value.
void SSAUpdater::AddAvailableValue(BasicBlock *BB, Value *V) {
- assert(ProtoType != 0 && "Need to initialize SSAUpdater");
- assert(ProtoType == V->getType() &&
+ assert(PrototypeValue != 0 && "Need to initialize SSAUpdater");
+ assert(PrototypeValue->getType() == V->getType() &&
"All rewritten values must have the same type");
getAvailableVals(AV)[BB] = V;
}
@@ -149,7 +148,7 @@ Value *SSAUpdater::GetValueInMiddleOfBlock(BasicBlock *BB) {
// If there are no predecessors, just return undef.
if (PredValues.empty())
- return UndefValue::get(ProtoType);
+ return UndefValue::get(PrototypeValue->getType());
// Otherwise, if all the merged values are the same, just use it.
if (SingularValue != 0)
@@ -169,7 +168,9 @@ Value *SSAUpdater::GetValueInMiddleOfBlock(BasicBlock *BB) {
}
// Ok, we have no way out, insert a new one now.
- PHINode *InsertedPHI = PHINode::Create(ProtoType, ProtoName, &BB->front());
+ PHINode *InsertedPHI = PHINode::Create(PrototypeValue->getType(),
+ PrototypeValue->getName(),
+ &BB->front());
InsertedPHI->reserveOperandSpace(PredValues.size());
// Fill in all the predecessors of the PHI.
@@ -281,14 +282,15 @@ public:
/// GetUndefVal - Get an undefined value of the same type as the value
/// being handled.
static Value *GetUndefVal(BasicBlock *BB, SSAUpdater *Updater) {
- return UndefValue::get(Updater->ProtoType);
+ return UndefValue::get(Updater->PrototypeValue->getType());
}
/// CreateEmptyPHI - Create a new PHI instruction in the specified block.
/// Reserve space for the operands but do not fill them in yet.
static Value *CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds,
SSAUpdater *Updater) {
- PHINode *PHI = PHINode::Create(Updater->ProtoType, Updater->ProtoName,
+ PHINode *PHI = PHINode::Create(Updater->PrototypeValue->getType(),
+ Updater->PrototypeValue->getName(),
&BB->front());
PHI->reserveOperandSpace(NumPreds);
return PHI;
generated by cgit v1.1 at 2025-03-15 07:55:03 +0000