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[sil-devirtualizer] Support devirtualization of try_apply instructions.

Browse Source 
rdar://21909405

Swift SVN r30710
This commit is contained in:
Roman Levenstein
2015-07-28 00:11:38 +00:00
parent 85367420bd
commit 696da80ca0
6 changed files with 374 additions and 107 deletions
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129
lib/SILPasses/Devirtualizer.cpp
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@@ -71,7 +71,7 @@ public:
<< "\n");
for (auto &BB : F) {
for (auto II = BB.begin(), IE = BB.end(); II != IE;) {
ApplyInst *AI = dyn_cast<ApplyInst>(&*II);
FullApplySite AI = FullApplySite::isa(&*II);
++II;
if (!AI)
@@ -109,37 +109,56 @@ SILTransform *swift::createDevirtualizer() {
}
// A utility function for cloning the apply instruction.
static ApplyInst *CloneApply(ApplyInst *AI, SILBuilder &Builder) {
static FullApplySite CloneApply(FullApplySite AI, SILBuilder &Builder) {
// Clone the Apply.
auto Args = AI->getArguments();
auto Args = AI.getArguments();
SmallVector<SILValue, 8> Ret(Args.size());
for (unsigned i = 0, e = Args.size(); i != e; ++i)
Ret[i] = Args[i];
auto NAI = Builder.createApply(AI->getLoc(), AI->getCallee(),
AI->getSubstCalleeSILType(),
AI->getType(),
AI->getSubstitutions(),
Ret);
NAI->setDebugScope(AI->getDebugScope());
FullApplySite NAI;
switch (AI.getInstruction()->getKind()) {
case ValueKind::ApplyInst:
NAI = Builder.createApply(AI.getLoc(), AI.getCallee(),
AI.getSubstCalleeSILType(),
AI.getType(),
AI.getSubstitutions(),
Ret);
break;
case ValueKind::TryApplyInst: {
auto *TryApplyI = cast<TryApplyInst>(AI.getInstruction());
NAI = Builder.createTryApply(AI.getLoc(), AI.getCallee(),
AI.getSubstCalleeSILType(),
AI.getSubstitutions(),
Ret,
TryApplyI->getNormalBB(),
TryApplyI->getErrorBB());
}
break;
default:
llvm_unreachable("Trying to clone an unsupported apply instruction");
}
NAI.getInstruction()->setDebugScope(AI.getDebugScope());
return NAI;
}
/// Insert monomorphic inline caches for a specific class or metatype
/// type \p SubClassTy.
static ApplyInst* speculateMonomorphicTarget(ApplyInst *AI,
SILType SubType) {
static FullApplySite speculateMonomorphicTarget(FullApplySite AI,
SILType SubType) {
// Bail if this class_method cannot be devirtualized.
if (!canDevirtualizeClassMethod(AI, SubType))
return nullptr;
return FullApplySite();
// Create a diamond shaped control flow and a checked_cast_branch
// instruction that checks the exact type of the object.
// This cast selects between two paths: one that calls the slow dynamic
// dispatch and one that calls the specific method.
SILBasicBlock::iterator It = AI;
SILFunction *F = AI->getFunction();
SILBasicBlock *Entry = AI->getParent();
SILBasicBlock::iterator It = AI.getInstruction();
SILFunction *F = AI.getFunction();
SILBasicBlock *Entry = AI.getParent();
// Iden is the basic block containing the direct call.
SILBasicBlock *Iden = F->createBasicBlock();
@@ -149,13 +168,13 @@ static ApplyInst* speculateMonomorphicTarget(ApplyInst *AI,
SILBasicBlock *Continue = Entry->splitBasicBlock(It);
SILBuilderWithScope<> Builder(Entry, AI->getDebugScope());
SILBuilderWithScope<> Builder(Entry, AI.getDebugScope());
// Create the checked_cast_branch instruction that checks at runtime if the
// class instance is identical to the SILType.
ClassMethodInst *CMI = cast<ClassMethodInst>(AI->getCallee());
ClassMethodInst *CMI = cast<ClassMethodInst>(AI.getCallee());
It = Builder.createCheckedCastBranch(AI->getLoc(), /*exact*/ true,
It = Builder.createCheckedCastBranch(AI.getLoc(), /*exact*/ true,
CMI->getOperand(), SubType, Iden,
Virt);
@@ -181,8 +200,8 @@ static ApplyInst* speculateMonomorphicTarget(ApplyInst *AI,
}
// Copy the two apply instructions into the two blocks.
ApplyInst *IdenAI = CloneApply(AI, IdenBuilder);
ApplyInst *VirtAI = CloneApply(AI, VirtBuilder);
FullApplySite IdenAI = CloneApply(AI, IdenBuilder);
FullApplySite VirtAI = CloneApply(AI, VirtBuilder);
// See if Continue has a release on self as the instruction right after the
// apply. If it exists, move it into position in the diamond.
@@ -200,15 +219,23 @@ static ApplyInst* speculateMonomorphicTarget(ApplyInst *AI,
// Create a PHInode for returning the return value from both apply
// instructions.
SILArgument *Arg = Continue->createBBArg(AI->getType());
IdenBuilder.createBranch(AI->getLoc(), Continue, ArrayRef<SILValue>(IdenAI))
->setDebugScope(AI->getDebugScope());
VirtBuilder.createBranch(AI->getLoc(), Continue, ArrayRef<SILValue>(VirtAI))
->setDebugScope(AI->getDebugScope());
SILArgument *Arg = Continue->createBBArg(AI.getType());
if (!isa<TryApplyInst>(AI)) {
IdenBuilder.createBranch(AI.getLoc(), Continue,
ArrayRef<SILValue>(IdenAI.getInstruction()))->setDebugScope(
AI.getDebugScope());
VirtBuilder.createBranch(AI.getLoc(), Continue,
ArrayRef<SILValue>(VirtAI.getInstruction()))->setDebugScope(
AI.getDebugScope());
}
// Remove the old Apply instruction.
AI->replaceAllUsesWith(Arg);
AI->eraseFromParent();
if (!isa<TryApplyInst>(AI))
AI.getInstruction()->replaceAllUsesWith(Arg);
auto *OriginalBB = AI.getParent();
AI.getInstruction()->eraseFromParent();
if (OriginalBB->empty())
OriginalBB->removeFromParent();
// Update the stats.
NumTargetsPredicted++;
@@ -222,6 +249,32 @@ static ApplyInst* speculateMonomorphicTarget(ApplyInst *AI,
if (CMI->hasOneUse())
CMI->moveBefore(CMI->use_begin()->getUser());
// Split critical edges resulting from VirtAI.
if (auto *TAI = dyn_cast<TryApplyInst>(VirtAI)) {
auto *ErrorBB = TAI->getFunction()->createBasicBlock();
ErrorBB->createBBArg(TAI->getErrorBB()->getBBArg(0)->getType());
Builder.setInsertionPoint(ErrorBB);
Builder.createBranch(TAI->getLoc(), TAI->getErrorBB(),
{ErrorBB->getBBArg(0)});
auto *NormalBB = TAI->getFunction()->createBasicBlock();
NormalBB->createBBArg(TAI->getNormalBB()->getBBArg(0)->getType());
Builder.setInsertionPoint(NormalBB);
Builder.createBranch(TAI->getLoc(), TAI->getNormalBB(),
{NormalBB->getBBArg(0) });
Builder.setInsertionPoint(VirtAI.getInstruction());
SmallVector<SILValue, 4> Args;
for (auto Arg : VirtAI.getArguments()) {
Args.push_back(Arg);
}
FullApplySite NewVirtAI = Builder.createTryApply(VirtAI.getLoc(), VirtAI.getCallee(),
VirtAI.getSubstCalleeSILType(), VirtAI.getSubstitutions(),
Args, NormalBB, ErrorBB);
VirtAI.getInstruction()->eraseFromParent();
VirtAI = NewVirtAI;
}
return VirtAI;
}
@@ -235,12 +288,12 @@ static ApplyInst* speculateMonomorphicTarget(ApplyInst *AI,
/// \p CD static class of the instance whose method is being invoked
/// \p Subs set of direct subclasses of this class
static bool isDefaultCaseKnown(ClassHierarchyAnalysis *CHA,
ApplyInst *AI,
FullApplySite AI,
ClassDecl *CD,
ClassHierarchyAnalysis::ClassList &Subs) {
ClassMethodInst *CMI = cast<ClassMethodInst>(AI->getCallee());
ClassMethodInst *CMI = cast<ClassMethodInst>(AI.getCallee());
auto *Method = CMI->getMember().getFuncDecl();
const DeclContext *DC = AI->getModule().getAssociatedContext();
const DeclContext *DC = AI.getModule().getAssociatedContext();
if (CD->isFinal())
return true;
@@ -262,7 +315,7 @@ static bool isDefaultCaseKnown(ClassHierarchyAnalysis *CHA,
case Accessibility::Public:
return false;
case Accessibility::Internal:
if (!AI->getModule().isWholeModule())
if (!AI.getModule().isWholeModule())
return false;
break;
case Accessibility::Private:
@@ -323,9 +376,9 @@ static bool isDefaultCaseKnown(ClassHierarchyAnalysis *CHA,
/// \brief Try to speculate the call target for the call \p AI. This function
/// returns true if a change was made.
static bool tryToSpeculateTarget(ApplyInst *AI,
static bool tryToSpeculateTarget(FullApplySite AI,
ClassHierarchyAnalysis *CHA) {
ClassMethodInst *CMI = cast<ClassMethodInst>(AI->getCallee());
ClassMethodInst *CMI = cast<ClassMethodInst>(AI.getCallee());
// We cannot devirtualize in cases where dynamic calls are
// semantically required.
@@ -341,7 +394,7 @@ static bool tryToSpeculateTarget(ApplyInst *AI,
// Bail if any generic types parameters of the class instance type are
// unbound.
// We cannot devirtualize unbound generic calls yet.
if (isClassWithUnboundGenericParameters(SubType, AI->getModule()))
if (isClassWithUnboundGenericParameters(SubType, AI.getModule()))
return false;
auto &M = CMI->getModule();
@@ -365,7 +418,7 @@ static bool tryToSpeculateTarget(ApplyInst *AI,
DEBUG(llvm::dbgs() << "Inserting monomorphic speculative call for class " <<
CD->getName() << "\n");
return speculateMonomorphicTarget(AI, SubType);
return !!speculateMonomorphicTarget(AI, SubType);
}
// Collect the direct subclasses for the class.
@@ -511,11 +564,11 @@ namespace {
bool Changed = false;
// Collect virtual calls that may be specialized.
SmallVector<ApplyInst *, 16> ToSpecialize;
SmallVector<FullApplySite, 16> ToSpecialize;
for (auto &BB : *getFunction()) {
for (auto II = BB.begin(), IE = BB.end(); II != IE; ++II) {
auto *AI = dyn_cast<ApplyInst>(&*II);
if (AI && isa<ClassMethodInst>(AI->getCallee()))
FullApplySite AI = FullApplySite::isa(&*II);
if (AI && isa<ClassMethodInst>(AI.getCallee()))
ToSpecialize.push_back(AI);
}
}