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swift-mirror/lib/SILOptimizer/Utils/Local.cpp

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//===--- Local.cpp - Functions that perform local SIL transformations. ----===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#include "swift/SILOptimizer/Utils/Local.h"
#include "swift/SILOptimizer/Analysis/Analysis.h"
#include "swift/SILOptimizer/Analysis/ARCAnalysis.h"
#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
#include "swift/SIL/DynamicCasts.h"
#include "swift/SIL/SILArgument.h"
#include "swift/SIL/SILBuilder.h"
#include "swift/SIL/SILModule.h"
#include "swift/SIL/SILUndef.h"
#include "swift/SIL/TypeLowering.h"
#include "swift/SIL/DebugUtils.h"
#include "swift/SIL/InstructionUtils.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/Support/CommandLine.h"
#include <deque>
using namespace swift;
/// \brief Perform a fast local check to see if the instruction is dead.
///
/// This routine only examines the state of the instruction at hand.
bool
swift::isInstructionTriviallyDead(SILInstruction *I) {
// At Onone, consider all uses, including the debug_info.
// This way, debug_info is preserved at Onone.
if (!I->use_empty() &&
I->getModule().getOptions().Optimization <= SILOptions::SILOptMode::None)
return false;
if (!hasNoUsesExceptDebug(I) || isa<TermInst>(I))
return false;
if (auto *BI = dyn_cast<BuiltinInst>(I)) {
return !BI->mayHaveSideEffects();
}
// condfail instructions that obviously can't fail are dead.
if (auto *CFI = dyn_cast<CondFailInst>(I))
if (auto *ILI = dyn_cast<IntegerLiteralInst>(CFI->getOperand()))
if (!ILI->getValue())
return true;
// mark_uninitialized is never dead.
if (isa<MarkUninitializedInst>(I))
return false;
if (isa<DebugValueInst>(I) || isa<DebugValueAddrInst>(I))
return false;
// These invalidate enums so "write" memory, but that is not an essential
// operation so we can remove these if they are trivially dead.
if (isa<UncheckedTakeEnumDataAddrInst>(I))
return true;
if (!I->mayHaveSideEffects())
return true;
return false;
}
namespace {
using CallbackTy = std::function<void(SILInstruction *)>;
} // end anonymous namespace
void swift::
recursivelyDeleteTriviallyDeadInstructions(ArrayRef<SILInstruction *> IA,
bool Force, CallbackTy Callback) {
// Delete these instruction and others that become dead after it's deleted.
llvm::SmallPtrSet<SILInstruction *, 8> DeadInsts;
for (auto I : IA) {
// If the instruction is not dead and force is false, do nothing.
if (Force || isInstructionTriviallyDead(I))
DeadInsts.insert(I);
}
llvm::SmallPtrSet<SILInstruction *, 8> NextInsts;
while (!DeadInsts.empty()) {
for (auto I : DeadInsts) {
// Call the callback before we mutate the to be deleted instruction in any
// way.
Callback(I);
// Check if any of the operands will become dead as well.
MutableArrayRef<Operand> Ops = I->getAllOperands();
for (Operand &Op : Ops) {
SILValue OpVal = Op.get();
if (!OpVal)
continue;
// Remove the reference from the instruction being deleted to this
// operand.
Op.drop();
// If the operand is an instruction that is only used by the instruction
// being deleted, delete it.
if (SILInstruction *OpValInst = dyn_cast<SILInstruction>(OpVal))
if (!DeadInsts.count(OpValInst) &&
isInstructionTriviallyDead(OpValInst))
NextInsts.insert(OpValInst);
}
// If we have a function ref inst, we need to especially drop its function
// argument so that it gets a proper ref decrement.
auto *FRI = dyn_cast<FunctionRefInst>(I);
if (FRI && FRI->getReferencedFunction())
FRI->dropReferencedFunction();
}
for (auto I : DeadInsts) {
// This will remove this instruction and all its uses.
eraseFromParentWithDebugInsts(I);
}
NextInsts.swap(DeadInsts);
NextInsts.clear();
}
}
/// \brief If the given instruction is dead, delete it along with its dead
/// operands.
///
/// \param I The instruction to be deleted.
/// \param Force If Force is set, don't check if the top level instruction is
/// considered dead - delete it regardless.
void swift::recursivelyDeleteTriviallyDeadInstructions(SILInstruction *I,
bool Force,
CallbackTy Callback) {
ArrayRef<SILInstruction *> AI = ArrayRef<SILInstruction *>(I);
recursivelyDeleteTriviallyDeadInstructions(AI, Force, Callback);
}
void swift::eraseUsesOfInstruction(SILInstruction *Inst,
CallbackTy Callback) {
for (auto UI = Inst->use_begin(), E = Inst->use_end(); UI != E;) {
auto *User = UI->getUser();
UI++;
// If the instruction itself has any uses, recursively zap them so that
// nothing uses this instruction.
eraseUsesOfInstruction(User, Callback);
// Walk through the operand list and delete any random instructions that
// will become trivially dead when this instruction is removed.
for (auto &Op : User->getAllOperands()) {
if (auto *OpI = dyn_cast<SILInstruction>(Op.get())) {
// Don't recursively delete the pointer we're getting in.
if (OpI != Inst) {
Op.drop();
recursivelyDeleteTriviallyDeadInstructions(OpI, false, Callback);
}
}
}
Callback(User);
User->eraseFromParent();
}
}
void swift::eraseUsesOfValue(SILValue V) {
for (auto UI = V->use_begin(), E = V->use_end(); UI != E;) {
auto *User = UI->getUser();
UI++;
// If the instruction itself has any uses, recursively zap them so that
// nothing uses this instruction.
eraseUsesOfValue(User);
// Walk through the operand list and delete any random instructions that
// will become trivially dead when this instruction is removed.
for (auto &Op : User->getAllOperands()) {
if (auto *OpI = dyn_cast<SILInstruction>(Op.get())) {
// Don't recursively delete the pointer we're getting in.
if (Op.get() != V) {
Op.drop();
recursivelyDeleteTriviallyDeadInstructions(OpI, false,
[](SILInstruction *){});
}
}
}
User->eraseFromParent();
}
}
// Devirtualization of functions with covariant return types produces
// a result that is not an apply, but takes an apply as an
// argument. Attempt to dig the apply out from this result.
FullApplySite swift::findApplyFromDevirtualizedResult(SILInstruction *I) {
if (!I)
return FullApplySite();
if (auto Apply = FullApplySite::isa(I))
return Apply;
if (!I->getNumOperands())
return FullApplySite();
if (isa<UpcastInst>(I) || isa<EnumInst>(I) || isa<UncheckedRefCastInst>(I))
return findApplyFromDevirtualizedResult(
dyn_cast<SILInstruction>(I->getOperand(0)));
return FullApplySite();
}
// Replace a dead apply with a new instruction that computes the same
// value, and delete the old apply.
void swift::replaceDeadApply(ApplySite Old, ValueBase *New) {
auto *OldApply = Old.getInstruction();
if (!isa<TryApplyInst>(OldApply))
OldApply->replaceAllUsesWith(New);
recursivelyDeleteTriviallyDeadInstructions(OldApply, true);
}
bool swift::hasUnboundGenericTypes(TypeSubstitutionMap &SubsMap) {
// Check whether any of the substitutions are dependent.
for (auto &entry : SubsMap)
if (entry.second->getCanonicalType()->hasArchetype())
return true;
return false;
}
bool swift::hasUnboundGenericTypes(ArrayRef<Substitution> Subs) {
// Check whether any of the substitutions are dependent.
for (auto &sub : Subs)
if (sub.getReplacement()->getCanonicalType()->hasArchetype())
return true;
return false;
}
bool swift::hasDynamicSelfTypes(TypeSubstitutionMap &SubsMap) {
// Check whether any of the substitutions are refer to dynamic self.
for (auto &entry : SubsMap)
if (entry.second->getCanonicalType()->hasDynamicSelfType())
return true;
return false;
}
bool swift::hasDynamicSelfTypes(ArrayRef<Substitution> Subs) {
// Check whether any of the substitutions are refer to dynamic self.
for (auto &sub : Subs)
if (sub.getReplacement()->getCanonicalType()->hasDynamicSelfType())
return true;
return false;
}
bool swift::computeMayBindDynamicSelf(SILFunction *F) {
for (auto &BB : *F)
for (auto &I : BB)
if (auto Apply = FullApplySite::isa(&I))
if (hasDynamicSelfTypes(Apply.getSubstitutions()))
return true;
return false;
}
/// Find a new position for an ApplyInst's FuncRef so that it dominates its
/// use. Not that FunctionRefInsts may be shared by multiple ApplyInsts.
void swift::placeFuncRef(ApplyInst *AI, DominanceInfo *DT) {
FunctionRefInst *FuncRef = cast<FunctionRefInst>(AI->getCallee());
SILBasicBlock *DomBB =
DT->findNearestCommonDominator(AI->getParent(), FuncRef->getParent());
if (DomBB == AI->getParent() && DomBB != FuncRef->getParent())
// Prefer to place the FuncRef immediately before the call. Since we're
// moving FuncRef up, this must be the only call to it in the block.
FuncRef->moveBefore(AI);
else
// Otherwise, conservatively stick it at the beginning of the block.
FuncRef->moveBefore(&*DomBB->begin());
}
/// \brief Add an argument, \p val, to the branch-edge that is pointing into
/// block \p Dest. Return a new instruction and do not erase the old
/// instruction.
TermInst *swift::addArgumentToBranch(SILValue Val, SILBasicBlock *Dest,
TermInst *Branch) {
SILBuilderWithScope Builder(Branch);
if (CondBranchInst *CBI = dyn_cast<CondBranchInst>(Branch)) {
SmallVector<SILValue, 8> TrueArgs;
SmallVector<SILValue, 8> FalseArgs;
for (auto A : CBI->getTrueArgs())
TrueArgs.push_back(A);
for (auto A : CBI->getFalseArgs())
FalseArgs.push_back(A);
if (Dest == CBI->getTrueBB()) {
TrueArgs.push_back(Val);
assert(TrueArgs.size() == Dest->getNumBBArg());
} else {
FalseArgs.push_back(Val);
assert(FalseArgs.size() == Dest->getNumBBArg());
}
return Builder.createCondBranch(CBI->getLoc(), CBI->getCondition(),
CBI->getTrueBB(), TrueArgs,
CBI->getFalseBB(), FalseArgs);
}
if (BranchInst *BI = dyn_cast<BranchInst>(Branch)) {
SmallVector<SILValue, 8> Args;
for (auto A : BI->getArgs())
Args.push_back(A);
Args.push_back(Val);
assert(Args.size() == Dest->getNumBBArg());
return Builder.createBranch(BI->getLoc(), BI->getDestBB(), Args);
}
llvm_unreachable("unsupported terminator");
}
SILLinkage swift::getSpecializedLinkage(SILFunction *F, SILLinkage L) {
switch (L) {
case SILLinkage::Public:
case SILLinkage::PublicExternal:
case SILLinkage::Shared:
case SILLinkage::SharedExternal:
case SILLinkage::Hidden:
case SILLinkage::HiddenExternal:
// Specializations of public or hidden symbols can be shared by all TUs
// that specialize the definition.
// Treat stdlib_binary_only specially. We don't serialize the body of
// stdlib_binary_only functions so we can't mark them as Shared (making
// their visibility in the dylib hidden).
return F->hasSemanticsAttr("stdlib_binary_only") ? SILLinkage::Public
: SILLinkage::Shared;
case SILLinkage::Private:
case SILLinkage::PrivateExternal:
// Specializations of private symbols should remain so.
// TODO: maybe PrivateExternals should get SharedExternal (these are private
// functions from the stdlib which are specialized in another module).
return SILLinkage::Private;
}
}
/// Remove all instructions in the body of \p BB in safe manner by using
/// undef.
void swift::clearBlockBody(SILBasicBlock *BB) {
// Instructions in the dead block may be used by other dead blocks. Replace
// any uses of them with undef values.
while (!BB->empty()) {
// Grab the last instruction in the BB.
auto *Inst = &BB->back();
// Replace any still-remaining uses with undef values and erase.
Inst->replaceAllUsesWithUndef();
Inst->eraseFromParent();
}
}
// Handle the mechanical aspects of removing an unreachable block.
void swift::removeDeadBlock(SILBasicBlock *BB) {
// Clear the body of BB.
clearBlockBody(BB);
// Now that the BB is empty, eliminate it.
BB->eraseFromParent();
}
/// Cast a value into the expected, ABI compatible type if necessary.
/// This may happen e.g. when:
/// - a type of the return value is a subclass of the expected return type.
/// - actual return type and expected return type differ in optionality.
/// - both types are tuple-types and some of the elements need to be casted.
///
/// If CheckOnly flag is set, then this function only checks if the
/// required casting is possible. If it is not possible, then None
/// is returned.
///
/// If CheckOnly is not set, then a casting code is generated and the final
/// casted value is returned.
///
/// NOTE: We intentionally combine the checking of the cast's handling possibility
/// and the transformation performing the cast in the same function, to avoid
/// any divergence between the check and the implementation in the future.
///
/// NOTE: The implementation of this function is very closely related to the
/// rules checked by SILVerifier::requireABICompatibleFunctionTypes.
Optional<SILValue> swift::castValueToABICompatibleType(SILBuilder *B, SILLocation Loc,
SILValue Value,
SILType SrcTy, SILType DestTy,
bool CheckOnly) {
// No cast is required if types are the same.
if (SrcTy == DestTy)
return Value;
SILValue CastedValue;
auto &M = B->getModule();
OptionalTypeKind SrcOTK;
OptionalTypeKind DestOTK;
// Check if src and dest types are optional.
auto OptionalSrcTy = SrcTy.getSwiftRValueType()
.getAnyOptionalObjectType(SrcOTK);
auto OptionalDestTy = DestTy.getSwiftRValueType()
.getAnyOptionalObjectType(DestOTK);
// If both types are classes and dest is the superclass of src,
// simply perform an upcast.
if (SrcTy.getSwiftRValueType()->mayHaveSuperclass() &&
DestTy.getSwiftRValueType()->mayHaveSuperclass() &&
DestTy.isSuperclassOf(SrcTy)) {
if (CheckOnly)
return Value;
CastedValue = B->createUpcast(Loc, Value, DestTy);
return CastedValue;
}
SILType OptionalSrcLoweredTy;
SILType OptionalDestLoweredTy;
if (OptionalSrcTy)
OptionalSrcLoweredTy = M.Types.getLoweredType(OptionalSrcTy);
if (OptionalDestTy)
OptionalDestLoweredTy = M.Types.getLoweredType(OptionalDestTy);
// Both types are optional.
if (OptionalDestTy && OptionalSrcTy) {
// If both wrapped types are classes and dest is the superclass of src,
// simply perform an upcast.
if (OptionalDestTy->mayHaveSuperclass() &&
OptionalSrcTy->mayHaveSuperclass() &&
OptionalDestLoweredTy.isSuperclassOf(OptionalSrcLoweredTy)) {
// Insert upcast.
if (CheckOnly)
return Value;
CastedValue = B->createUpcast(Loc, Value, DestTy);
return CastedValue;
}
if (CheckOnly)
return castValueToABICompatibleType(B, Loc, Value,
OptionalSrcLoweredTy,
OptionalDestLoweredTy, CheckOnly);
// Unwrap the original optional value.
auto *SomeDecl = B->getASTContext().getOptionalSomeDecl(SrcOTK);
auto *NoneBB = B->getFunction().createBasicBlock();
auto *SomeBB = B->getFunction().createBasicBlock();
auto *CurBB = B->getInsertionPoint()->getParent();
auto *ContBB = CurBB->splitBasicBlock(B->getInsertionPoint());
ContBB->createBBArg(DestTy,nullptr);
SmallVector<std::pair<EnumElementDecl *, SILBasicBlock *>, 1> CaseBBs;
CaseBBs.push_back(std::make_pair(SomeDecl, SomeBB));
B->setInsertionPoint(CurBB);
B->createSwitchEnum(Loc, Value, NoneBB, CaseBBs);
// Handle the Some case.
B->setInsertionPoint(SomeBB);
SILValue UnwrappedValue = B->createUncheckedEnumData(Loc, Value,
SomeDecl);
// Cast the unwrapped value.
auto CastedUnwrappedValue =
castValueToABICompatibleType(B, Loc, UnwrappedValue,
OptionalSrcLoweredTy,
OptionalDestLoweredTy).getValue();
// Wrap into optional.
CastedValue = B->createOptionalSome(Loc, CastedUnwrappedValue,
DestOTK, DestTy);
B->createBranch(Loc, ContBB, {CastedValue});
// Handle the None case.
B->setInsertionPoint(NoneBB);
CastedValue = B->createOptionalNone(Loc, DestTy);
B->createBranch(Loc, ContBB, {CastedValue});
B->setInsertionPoint(ContBB->begin());
CastedValue = ContBB->getBBArg(0);
return CastedValue;
}
// Src is not optional, but dest is optional.
if (!OptionalSrcTy && OptionalDestTy) {
auto OptionalSrcCanTy = OptionalType::get(DestOTK,
SrcTy.getSwiftRValueType()).getCanonicalTypeOrNull();
auto LoweredOptionalSrcType = M.Types.getLoweredType(OptionalSrcCanTy);
if (CheckOnly)
return castValueToABICompatibleType(B, Loc, Value,
LoweredOptionalSrcType, DestTy,
CheckOnly);
// Wrap the source value into an optional first.
SILValue WrappedValue = B->createOptionalSome(Loc, Value,
DestOTK,
LoweredOptionalSrcType);
// Cast the wrapped value.
return castValueToABICompatibleType(B, Loc, WrappedValue,
WrappedValue->getType(),
DestTy);
}
// Both types are not optional.
if (SrcTy.getSwiftRValueType()->mayHaveSuperclass() &&
DestTy.getSwiftRValueType()->mayHaveSuperclass()) {
if (CheckOnly)
return Value;
if (DestTy.isSuperclassOf(SrcTy)) {
// Insert upcast.
CastedValue = B->createUpcast(Loc, Value, DestTy);
return CastedValue;
}
// Cast the reference.
CastedValue = B->createUncheckedBitCast(Loc, Value, DestTy);
return CastedValue;
}
// If B.Type needs to be casted to A.Type and
// A is a superclass of B, then it can be done by means
// of a simple upcast.
if (isa<AnyMetatypeType>(SrcTy.getSwiftRValueType()) &&
isa<AnyMetatypeType>(DestTy.getSwiftRValueType()) &&
SrcTy.isClassOrClassMetatype() && DestTy.isClassOrClassMetatype() &&
DestTy.getMetatypeInstanceType(M).isSuperclassOf(
SrcTy.getMetatypeInstanceType(M))) {
if (CheckOnly)
return Value;
CastedValue = B->createUpcast(Loc, Value, DestTy);
return CastedValue;
}
if (SrcTy.isAddress() && DestTy.isAddress()) {
if (CheckOnly)
return Value;
CastedValue = B->createUncheckedAddrCast(Loc, Value, DestTy);
return CastedValue;
}
if (SrcTy.isHeapObjectReferenceType() && DestTy.isHeapObjectReferenceType()) {
if (CheckOnly)
return Value;
CastedValue = B->createUncheckedRefCast(Loc, Value, DestTy);
return CastedValue;
}
// Handle tuple types.
// Extract elements, cast each of them, create a new tuple.
if (auto tup = SrcTy.getAs<TupleType>()) {
SmallVector<CanType, 1> aElements, bElements;
auto atypes = tup.getElementTypes();
aElements.append(atypes.begin(), atypes.end());
auto btypes = DestTy.getAs<TupleType>().getElementTypes();
bElements.append(btypes.begin(), btypes.end());
if (CheckOnly && aElements.size() != bElements.size())
return None;
assert (aElements.size() == bElements.size() &&
"Tuple types should have the same number of elements");
SmallVector<SILValue, 8> ExpectedTuple;
for (unsigned i : indices(aElements)) {
auto aa = M.Types.getLoweredType(aElements[i]),
bb = M.Types.getLoweredType(bElements[i]);
if (CheckOnly) {
if (!castValueToABICompatibleType(B, Loc, Value, aa, bb, CheckOnly).hasValue())
return None;
continue;
}
SILValue Element = B->createTupleExtract(Loc, Value, i);
// Cast the value if necessary.
Element = castValueToABICompatibleType(B, Loc, Element, aa, bb).getValue();
ExpectedTuple.push_back(Element);
}
if (CheckOnly)
return Value;
CastedValue = B->createTuple(Loc, DestTy, ExpectedTuple);
return CastedValue;
}
// Function types are interchangeable if they're also ABI-compatible.
if (SrcTy.getAs<SILFunctionType>()) {
if (DestTy.getAs<SILFunctionType>()) {
if (CheckOnly)
return Value;
// Insert convert_function.
CastedValue = B->createConvertFunction(Loc, Value, DestTy);
return CastedValue;
}
}
if (CheckOnly)
return None;
llvm_unreachable("Unknown combination of types for casting");
return SILValue();
}
bool swift::canCastValueToABICompatibleType(SILModule &M,
SILType SrcTy, SILType DestTy) {
SILBuilder B(*M.begin());
SILLocation Loc = ArtificialUnreachableLocation();
auto Result = castValueToABICompatibleType(&B, Loc, SILValue(),
SrcTy, DestTy,
/* CheckOnly */ true);
return Result.hasValue();
}
ProjectBoxInst *swift::getOrCreateProjectBox(AllocBoxInst *ABI) {
SILBasicBlock::iterator Iter(ABI);
Iter++;
assert(Iter != ABI->getParent()->end() &&
"alloc_box cannot be the last instruction of a block");
SILInstruction *NextInst = &*Iter;
if (auto *PBI = dyn_cast<ProjectBoxInst>(NextInst)) {
if (PBI->getOperand() == ABI)
return PBI;
}
SILBuilder B(NextInst);
return B.createProjectBox(ABI->getLoc(), ABI);
}
//===----------------------------------------------------------------------===//
// String Concatenation Optimizer
//===----------------------------------------------------------------------===//
namespace {
/// This is a helper class that performs optimization of string literals
/// concatenation.
class StringConcatenationOptimizer {
/// Apply instruction being optimized.
ApplyInst *AI;
/// Builder to be used for creation of new instructions.
SILBuilder &Builder;
/// Left string literal operand of a string concatenation.
StringLiteralInst *SLILeft = nullptr;
/// Right string literal operand of a string concatenation.
StringLiteralInst *SLIRight = nullptr;
/// Function used to construct the left string literal.
FunctionRefInst *FRILeft = nullptr;
/// Function used to construct the right string literal.
FunctionRefInst *FRIRight = nullptr;
/// Apply instructions used to construct left string literal.
ApplyInst *AILeft = nullptr;
/// Apply instructions used to construct right string literal.
ApplyInst *AIRight = nullptr;
/// String literal conversion function to be used.
FunctionRefInst *FRIConvertFromBuiltin = nullptr;
/// Result type of a function producing the concatenated string literal.
SILValue FuncResultType;
/// Internal helper methods
bool extractStringConcatOperands();
void adjustEncodings();
APInt getConcatenatedLength();
bool isAscii() const;
public:
StringConcatenationOptimizer(ApplyInst *AI, SILBuilder &Builder)
: AI(AI), Builder(Builder) {}
/// Tries to optimize a given apply instruction if it is a
/// concatenation of string literals.
///
/// Returns a new instruction if optimization was possible.
SILInstruction *optimize();
};
} // end anonymous namespace
/// Checks operands of a string concatenation operation to see if
/// optimization is applicable.
///
/// Returns false if optimization is not possible.
/// Returns true and initializes internal fields if optimization is possible.
bool StringConcatenationOptimizer::extractStringConcatOperands() {
auto *Fn = AI->getCalleeFunction();
if (!Fn)
return false;
if (AI->getNumOperands() != 3 || !Fn->hasSemanticsAttr("string.concat"))
return false;
// Left and right operands of a string concatenation operation.
AILeft = dyn_cast<ApplyInst>(AI->getOperand(1));
AIRight = dyn_cast<ApplyInst>(AI->getOperand(2));
if (!AILeft || !AIRight)
return false;
FRILeft = dyn_cast<FunctionRefInst>(AILeft->getCallee());
FRIRight = dyn_cast<FunctionRefInst>(AIRight->getCallee());
if (!FRILeft || !FRIRight)
return false;
auto *FRILeftFun = FRILeft->getReferencedFunction();
auto *FRIRightFun = FRIRight->getReferencedFunction();
if (FRILeftFun->getEffectsKind() >= EffectsKind::ReadWrite ||
FRIRightFun->getEffectsKind() >= EffectsKind::ReadWrite)
return false;
if (!FRILeftFun->hasSemanticsAttrs() || !FRIRightFun->hasSemanticsAttrs())
return false;
auto AILeftOperandsNum = AILeft->getNumOperands();
auto AIRightOperandsNum = AIRight->getNumOperands();
// makeUTF16 should have following parameters:
// (start: RawPointer, numberOfCodeUnits: Word)
// makeUTF8 should have following parameters:
// (start: RawPointer, byteSize: Word, isASCII: Int1)
if (!((FRILeftFun->hasSemanticsAttr("string.makeUTF16") &&
AILeftOperandsNum == 4) ||
(FRILeftFun->hasSemanticsAttr("string.makeUTF8") &&
AILeftOperandsNum == 5) ||
(FRIRightFun->hasSemanticsAttr("string.makeUTF16") &&
AIRightOperandsNum == 4) ||
(FRIRightFun->hasSemanticsAttr("string.makeUTF8") &&
AIRightOperandsNum == 5)))
return false;
SLILeft = dyn_cast<StringLiteralInst>(AILeft->getOperand(1));
SLIRight = dyn_cast<StringLiteralInst>(AIRight->getOperand(1));
if (!SLILeft || !SLIRight)
return false;
// Only UTF-8 and UTF-16 encoded string literals are supported by this
// optimization.
if (SLILeft->getEncoding() != StringLiteralInst::Encoding::UTF8 &&
SLILeft->getEncoding() != StringLiteralInst::Encoding::UTF16)
return false;
if (SLIRight->getEncoding() != StringLiteralInst::Encoding::UTF8 &&
SLIRight->getEncoding() != StringLiteralInst::Encoding::UTF16)
return false;
return true;
}
/// Ensures that both string literals to be concatenated use the same
/// UTF encoding. Converts UTF-8 into UTF-16 if required.
void StringConcatenationOptimizer::adjustEncodings() {
if (SLILeft->getEncoding() == SLIRight->getEncoding()) {
FRIConvertFromBuiltin = FRILeft;
if (SLILeft->getEncoding() == StringLiteralInst::Encoding::UTF8) {
FuncResultType = AILeft->getOperand(4);
} else {
FuncResultType = AILeft->getOperand(3);
}
return;
}
Builder.setCurrentDebugScope(AI->getDebugScope());
// If one of the string literals is UTF8 and another one is UTF16,
// convert the UTF8-encoded string literal into UTF16-encoding first.
if (SLILeft->getEncoding() == StringLiteralInst::Encoding::UTF8 &&
SLIRight->getEncoding() == StringLiteralInst::Encoding::UTF16) {
FuncResultType = AIRight->getOperand(3);
FRIConvertFromBuiltin = FRIRight;
// Convert UTF8 representation into UTF16.
SLILeft = Builder.createStringLiteral(AI->getLoc(), SLILeft->getValue(),
StringLiteralInst::Encoding::UTF16);
}
if (SLIRight->getEncoding() == StringLiteralInst::Encoding::UTF8 &&
SLILeft->getEncoding() == StringLiteralInst::Encoding::UTF16) {
FuncResultType = AILeft->getOperand(3);
FRIConvertFromBuiltin = FRILeft;
// Convert UTF8 representation into UTF16.
SLIRight = Builder.createStringLiteral(AI->getLoc(), SLIRight->getValue(),
StringLiteralInst::Encoding::UTF16);
}
// It should be impossible to have two operands with different
// encodings at this point.
assert(SLILeft->getEncoding() == SLIRight->getEncoding() &&
"Both operands of string concatenation should have the same encoding");
}
/// Computes the length of a concatenated string literal.
APInt StringConcatenationOptimizer::getConcatenatedLength() {
// Real length of string literals computed based on its contents.
// Length is in code units.
auto SLILenLeft = SLILeft->getCodeUnitCount();
(void) SLILenLeft;
auto SLILenRight = SLIRight->getCodeUnitCount();
(void) SLILenRight;
// Length of string literals as reported by string.make functions.
auto *LenLeft = dyn_cast<IntegerLiteralInst>(AILeft->getOperand(2));
auto *LenRight = dyn_cast<IntegerLiteralInst>(AIRight->getOperand(2));
// Real and reported length should be the same.
assert(SLILenLeft == LenLeft->getValue() &&
"Size of string literal in @_semantics(string.make) is wrong");
assert(SLILenRight == LenRight->getValue() &&
"Size of string literal in @_semantics(string.make) is wrong");
// Compute length of the concatenated literal.
return LenLeft->getValue() + LenRight->getValue();
}
/// Computes the isAscii flag of a concatenated UTF8-encoded string literal.
bool StringConcatenationOptimizer::isAscii() const{
// Add the isASCII argument in case of UTF8.
// IsASCII is true only if IsASCII of both literals is true.
auto *AsciiLeft = dyn_cast<IntegerLiteralInst>(AILeft->getOperand(3));
auto *AsciiRight = dyn_cast<IntegerLiteralInst>(AIRight->getOperand(3));
auto IsAsciiLeft = AsciiLeft->getValue() == 1;
auto IsAsciiRight = AsciiRight->getValue() == 1;
return IsAsciiLeft && IsAsciiRight;
}
SILInstruction *StringConcatenationOptimizer::optimize() {
// Bail out if string literals concatenation optimization is
// not possible.
if (!extractStringConcatOperands())
return nullptr;
// Perform string literal encodings adjustments if needed.
adjustEncodings();
// Arguments of the new StringLiteralInst to be created.
SmallVector<SILValue, 4> Arguments;
// Encoding to be used for the concatenated string literal.
auto Encoding = SLILeft->getEncoding();
// Create a concatenated string literal.
Builder.setCurrentDebugScope(AI->getDebugScope());
auto LV = SLILeft->getValue();
auto RV = SLIRight->getValue();
auto *NewSLI =
Builder.createStringLiteral(AI->getLoc(), LV + Twine(RV), Encoding);
Arguments.push_back(NewSLI);
// Length of the concatenated literal according to its encoding.
auto *Len = Builder.createIntegerLiteral(
AI->getLoc(), AILeft->getOperand(2)->getType(), getConcatenatedLength());
Arguments.push_back(Len);
// isAscii flag for UTF8-encoded string literals.
if (Encoding == StringLiteralInst::Encoding::UTF8) {
bool IsAscii = isAscii();
auto ILType = AILeft->getOperand(3)->getType();
auto *Ascii =
Builder.createIntegerLiteral(AI->getLoc(), ILType, intmax_t(IsAscii));
Arguments.push_back(Ascii);
}
// Type.
Arguments.push_back(FuncResultType);
auto FnTy = FRIConvertFromBuiltin->getType();
auto STResultType = FnTy.castTo<SILFunctionType>()->getResult().getSILType();
return Builder.createApply(AI->getLoc(), FRIConvertFromBuiltin, FnTy,
STResultType, ArrayRef<Substitution>(), Arguments,
false);
}
/// Top level entry point
SILInstruction *swift::tryToConcatenateStrings(ApplyInst *AI, SILBuilder &B) {
return StringConcatenationOptimizer(AI, B).optimize();
}
//===----------------------------------------------------------------------===//
// Closure Deletion
//===----------------------------------------------------------------------===//
static bool useDoesNotKeepClosureAlive(const SILInstruction *I) {
switch (I->getKind()) {
case ValueKind::StrongRetainInst:
case ValueKind::StrongReleaseInst:
case ValueKind::RetainValueInst:
case ValueKind::ReleaseValueInst:
case ValueKind::DebugValueInst:
return true;
default:
return false;
}
}
void swift::releasePartialApplyCapturedArg(SILBuilder &Builder, SILLocation Loc,
SILValue Arg, SILParameterInfo PInfo,
InstModCallbacks Callbacks) {
// If we have a non-trivial type and the argument is passed in @inout, we do
// not need to destroy it here. This is something that is implicit in the
// partial_apply design that will be revisited when partial_apply is
// redesigned.
if (PInfo.isIndirectMutating())
return;
if (isa<AllocStackInst>(Arg)) {
return;
}
// If we have a trivial type, we do not need to put in any extra releases.
if (Arg->getType().isTrivial(Builder.getModule()))
return;
// Otherwise, we need to destroy the argument.
if (Arg->getType().isObject()) {
if (Arg->getType().hasReferenceSemantics()) {
auto U = Builder.emitStrongRelease(Loc, Arg);
if (U.isNull())
return;
if (auto *SRI = U.dyn_cast<StrongRetainInst *>()) {
Callbacks.DeleteInst(SRI);
return;
}
Callbacks.CreatedNewInst(U.get<StrongReleaseInst *>());
return;
}
auto U = Builder.emitReleaseValue(Loc, Arg);
if (U.isNull())
return;
if (auto *RVI = U.dyn_cast<RetainValueInst *>()) {
Callbacks.DeleteInst(RVI);
return;
}
Callbacks.CreatedNewInst(U.get<ReleaseValueInst *>());
return;
}
SILInstruction *NewInst = Builder.emitDestroyAddrAndFold(Loc, Arg);
Callbacks.CreatedNewInst(NewInst);
}
/// For each captured argument of PAI, decrement the ref count of the captured
/// argument as appropriate at each of the post dominated release locations
/// found by Tracker.
static void releaseCapturedArgsOfDeadPartialApply(PartialApplyInst *PAI,
ReleaseTracker &Tracker,
InstModCallbacks Callbacks) {
SILBuilderWithScope Builder(PAI);
SILLocation Loc = PAI->getLoc();
CanSILFunctionType PAITy =
dyn_cast<SILFunctionType>(PAI->getCallee()->getType().getSwiftType());
// Emit a destroy value for each captured closure argument.
ArrayRef<SILParameterInfo> Params = PAITy->getParameters();
auto Args = PAI->getArguments();
unsigned Delta = Params.size() - Args.size();
assert(Delta <= Params.size() && "Error, more Args to partial apply than "
"params in its interface.");
for (auto *FinalRelease : Tracker.getFinalReleases()) {
Builder.setInsertionPoint(FinalRelease);
for (unsigned AI = 0, AE = Args.size(); AI != AE; ++AI) {
SILValue Arg = Args[AI];
SILParameterInfo Param = Params[AI + Delta];
releasePartialApplyCapturedArg(Builder, Loc, Arg, Param, Callbacks);
}
}
}
/// TODO: Generalize this to general objects.
bool swift::tryDeleteDeadClosure(SILInstruction *Closure,
InstModCallbacks Callbacks) {
// We currently only handle locally identified values that do not escape. We
// also assume that the partial apply does not capture any addresses.
if (!isa<PartialApplyInst>(Closure) && !isa<ThinToThickFunctionInst>(Closure))
return false;
// We only accept a user if it is an ARC object that can be removed if the
// object is dead. This should be expanded in the future. This also ensures
// that we are locally identified and non-escaping since we only allow for
// specific ARC users.
ReleaseTracker Tracker([](const SILInstruction *I) -> bool {
return useDoesNotKeepClosureAlive(I);
});
// Find the ARC Users and the final retain, release.
if (!getFinalReleasesForValue(SILValue(Closure), Tracker))
return false;
// If we have a partial_apply, release each captured argument at each one of
// the final release locations of the partial apply.
if (auto *PAI = dyn_cast<PartialApplyInst>(Closure))
releaseCapturedArgsOfDeadPartialApply(PAI, Tracker, Callbacks);
// Then delete all user instructions.
for (auto *User : Tracker.getTrackedUsers()) {
assert(!User->hasValue() && "We expect only ARC operations without "
"results. This is true b/c of "
"isARCOperationRemovableIfObjectIsDead");
Callbacks.DeleteInst(User);
}
// Finally delete the closure.
Callbacks.DeleteInst(Closure);
return true;
}
//===----------------------------------------------------------------------===//
// Value Lifetime
//===----------------------------------------------------------------------===//
// Record a use by marking it's block and adding it to the initial LiveIn set.
void ValueLifetimeAnalysis::visitUser(SILInstruction *User) {
auto *BB = User->getParent();
UseBlocks.insert(BB);
if (BB != DefValue->getParentBB())
LiveIn.insert(BB);
}
// Generate ValueLifetimeAnalysis::liveIn.
//
// Propagate liveness backwards from an initial set of blocks in our
// liveIn set.
void ValueLifetimeAnalysis::propagateLiveness() {
// First populate a worklist of predecessors.
llvm::SmallVector<SILBasicBlock *, 64> Worklist;
for (auto *BB : LiveIn)
for (auto Pred : BB->getPreds())
Worklist.push_back(Pred);
// Now propagate liveness backwards until we hit the block that
// defines the value.
auto DefBB = DefValue->getParentBB();
while (!Worklist.empty()) {
auto *BB = Worklist.pop_back_val();
// If it's already in the set, then we've already queued and/or
// processed the predecessors.
if (BB == DefBB || !LiveIn.insert(BB).second)
continue;
for (auto Pred : BB->getPreds())
Worklist.push_back(Pred);
}
}
// Is any successor of BB in the LiveIn set?
bool ValueLifetimeAnalysis::successorHasLiveIn(SILBasicBlock *BB) {
for (auto &Succ : BB->getSuccessors())
if (LiveIn.count(Succ))
return true;
return false;
}
// Walk backwards in BB looking for last use of value DefValue.
SILInstruction *ValueLifetimeAnalysis::
findLastDirectUseInBlock(SILBasicBlock *BB) {
for (auto II = BB->rbegin(); II != BB->rend(); ++II) {
assert(DefValue != &*II && "Found def before finding use!");
for (auto &Oper : II->getAllOperands()) {
if (Oper.get() != DefValue)
continue;
return &*II;
}
}
llvm_unreachable("Expected to find use of value in block!");
}
// Walk backwards in BB looking for last use specified in the provided use
// list. This likely includes transitive uses of defValue.
SILInstruction *ValueLifetimeAnalysis::
findLastSpecifiedUseInBlock(SILBasicBlock *BB) {
for (auto II = BB->rbegin(); II != BB->rend(); ++II) {
assert(DefValue != &*II && "Found def before finding use!");
if (UserSet.count(&*II))
return &*II;
}
llvm_unreachable("Expected to find use of value in block!");
}
/// Generate ValueLifetime::lastUsers from ValueLifetimeAnalysis.
ValueLifetime ValueLifetimeAnalysis::computeLastUsers() {
ValueLifetime Lifetime;
for (auto *BB : UseBlocks) {
if (successorHasLiveIn(BB))
continue;
Lifetime.LastUsers.insert(UserSet.empty()
? findLastDirectUseInBlock(BB)
: findLastSpecifiedUseInBlock(BB));
}
return Lifetime;
}
//===----------------------------------------------------------------------===//
// Casts Optimization and Simplification
//===----------------------------------------------------------------------===//
/// \brief Get a substitution corresponding to the type witness.
/// Inspired by ProtocolConformance::getTypeWitnessByName.
static const Substitution *
getTypeWitnessByName(ProtocolConformance *conformance, Identifier name) {
// Find the named requirement.
AssociatedTypeDecl *assocType = nullptr;
assert(conformance && "Missing conformance information");
auto members = conformance->getProtocol()->lookupDirect(name);
for (auto member : members) {
assocType = dyn_cast<AssociatedTypeDecl>(member);
if (assocType)
break;
}
if (!assocType)
return nullptr;
if (!conformance->hasTypeWitness(assocType, nullptr)) {
return nullptr;
}
return &conformance->getTypeWitness(assocType, nullptr);
}
/// Check if is a bridging cast, i.e. one of the sides is
/// a bridged type.
static bool isBridgingCast(CanType SourceType, CanType TargetType) {
// Bridging casts cannot be further simplified.
auto TargetIsBridgeable = TargetType->isBridgeableObjectType();
auto SourceIsBridgeable = SourceType->isBridgeableObjectType();
if (TargetIsBridgeable != SourceIsBridgeable)
return true;
return false;
}
/// If target is a Swift type bridging to an ObjC type,
/// return the ObjC type it bridges to.
/// If target is an ObjC type, return this type.
static Type getCastFromObjC(SILModule &M, CanType source, CanType target) {
Optional<Type> BridgedTy = M.getASTContext().getBridgedToObjC(
M.getSwiftModule(), target, nullptr);
if (!BridgedTy.hasValue() || !BridgedTy.getValue())
return Type();
return BridgedTy.getValue();
}
/// Create a call of _forceBridgeFromObjectiveC_bridgeable or
/// _conditionallyBridgeFromObjectiveC_bridgeable which converts an ObjC
/// instance into a corresponding Swift type, conforming to
/// _ObjectiveCBridgeable.
SILInstruction *
CastOptimizer::
optimizeBridgedObjCToSwiftCast(SILInstruction *Inst,
bool isConditional,
SILValue Src,
SILValue Dest,
CanType Source,
CanType Target,
Type BridgedSourceTy,
Type BridgedTargetTy,
SILBasicBlock *SuccessBB,
SILBasicBlock *FailureBB) {
auto &M = Inst->getModule();
auto Loc = Inst->getLoc();
// The conformance to _BridgedToObjectiveC is statically known.
// Retrieve the bridging operation to be used if a static conformance
// to _BridgedToObjectiveC can be proven.
FuncDecl *BridgeFuncDecl =
isConditional
? M.getASTContext().getConditionallyBridgeFromObjectiveCBridgeable(nullptr)
: M.getASTContext().getForceBridgeFromObjectiveCBridgeable(nullptr);
assert(BridgeFuncDecl && "_forceBridgeFromObjectiveC should exist");
SILDeclRef FuncDeclRef(BridgeFuncDecl, SILDeclRef::Kind::Func);
// Lookup a function from the stdlib.
SILFunction *BridgedFunc = M.getOrCreateFunction(
Loc, FuncDeclRef, ForDefinition_t::NotForDefinition);
if (!BridgedFunc)
return nullptr;
CanType CanBridgedTy(BridgedTargetTy);
SILType SILBridgedTy = SILType::getPrimitiveObjectType(CanBridgedTy);
SILBuilderWithScope Builder(Inst);
SILValue SrcOp;
SILInstruction *NewI = nullptr;
assert(Src->getType().isAddress() && "Source should have an address type");
assert(Dest->getType().isAddress() && "Source should have an address type");
if (SILBridgedTy != Src->getType()) {
// Check if we can simplify a cast into:
// - ObjCTy to _ObjectiveCBridgeable._ObjectiveCType.
// - then convert _ObjectiveCBridgeable._ObjectiveCType to
// a Swift type using _forceBridgeFromObjectiveC.
// Generate a load for the source argument.
auto *Load = Builder.createLoad(Loc, Src);
// Try to convert the source into the expected ObjC type first.
if (Load->getType() == SILBridgedTy) {
// If type of the source and the expected ObjC type are
// equal, there is no need to generate the conversion
// from ObjCTy to _ObjectiveCBridgeable._ObjectiveCType.
if (isConditional) {
SILBasicBlock *CastSuccessBB = Inst->getFunction()->createBasicBlock();
CastSuccessBB->createBBArg(SILBridgedTy);
Builder.createBranch(Loc, CastSuccessBB, SILValue(Load));
Builder.setInsertionPoint(CastSuccessBB);
SrcOp = CastSuccessBB->getBBArg(0);
} else {
SrcOp = Load;
}
} else if (isConditional) {
SILBasicBlock *CastSuccessBB = Inst->getFunction()->createBasicBlock();
CastSuccessBB->createBBArg(SILBridgedTy);
NewI = Builder.createCheckedCastBranch(Loc, false, Load,
SILBridgedTy, CastSuccessBB,
FailureBB);
Builder.setInsertionPoint(CastSuccessBB);
SrcOp = CastSuccessBB->getBBArg(0);
} else {
NewI = Builder.createUnconditionalCheckedCast(Loc, Load,
SILBridgedTy);
SrcOp = NewI;
}
} else {
SrcOp = Src;
}
// Now emit the a cast from the casted ObjC object into a target type.
// This is done by means of calling _forceBridgeFromObjectiveC or
// _conditionallyBridgeFromObjectiveC_bridgeable from the Target type.
// Lookup the required function in the Target type.
// Lookup the _ObjectiveCBridgeable protocol.
auto BridgedProto =
M.getASTContext().getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
auto Conf =
M.getSwiftModule()->lookupConformance(Target, BridgedProto, nullptr);
assert(Conf.getInt() == ConformanceKind::Conforms &&
"_ObjectiveCBridgeable conformance should exist");
auto *Conformance = Conf.getPointer();
auto ParamTypes = BridgedFunc->getLoweredFunctionType()
->getParametersWithoutIndirectResult();
auto *FuncRef = Builder.createFunctionRef(Loc, BridgedFunc);
auto MetaTy = MetatypeType::get(Target, MetatypeRepresentation::Thick);
auto SILMetaTy = M.Types.getTypeLowering(MetaTy, 0).getLoweredType();
auto *MetaTyVal = Builder.createMetatype(Loc, SILMetaTy);
SmallVector<SILValue, 1> Args;
// Add substitutions
SmallVector<Substitution, 2> Subs;
auto Conformances =
M.getASTContext().AllocateUninitialized<ProtocolConformanceRef>(1);
Conformances[0] = ProtocolConformanceRef(Conformance);
Subs.push_back(Substitution(Target, Conformances));
const Substitution *DepTypeSubst = getTypeWitnessByName(
Conformance, M.getASTContext().getIdentifier("_ObjectiveCType"));
Subs.push_back(*DepTypeSubst);
auto SILFnTy = FuncRef->getType();
SILType SubstFnTy = SILFnTy.substGenericArgs(M, Subs);
SILType ResultTy = SubstFnTy.castTo<SILFunctionType>()->getSILResult();
// Temporary to hold the intermediate result.
AllocStackInst *Tmp = nullptr;
CanType OptionalTy;
OptionalTypeKind OTK;
SILValue InOutOptionalParam;
if (isConditional) {
// Create a temporary
OptionalTy = OptionalType::get(Dest->getType().getSwiftRValueType())
->getImplementationType()
.getCanonicalTypeOrNull();
OptionalTy.getAnyOptionalObjectType(OTK);
Tmp = Builder.createAllocStack(Loc,
SILType::getPrimitiveObjectType(OptionalTy));
InOutOptionalParam = Tmp;
} else {
InOutOptionalParam = Dest;
}
(void) ParamTypes;
assert(ParamTypes[0].getConvention() == ParameterConvention::Direct_Owned &&
"Parameter should be @owned");
// Emit a retain.
Builder.createRetainValue(Loc, SrcOp);
Args.push_back(InOutOptionalParam);
Args.push_back(SrcOp);
Args.push_back(MetaTyVal);
auto *AI = Builder.createApply(Loc, FuncRef, SubstFnTy, ResultTy, Subs, Args,
false);
// If the source of a cast should be destroyed, emit a release.
if (auto *UCCAI = dyn_cast<UnconditionalCheckedCastAddrInst>(Inst)) {
assert(UCCAI->getConsumptionKind() == CastConsumptionKind::TakeAlways);
if (UCCAI->getConsumptionKind() == CastConsumptionKind::TakeAlways) {
Builder.createReleaseValue(Loc, SrcOp);
}
}
if (auto *CCABI = dyn_cast<CheckedCastAddrBranchInst>(Inst)) {
if (CCABI->getConsumptionKind() == CastConsumptionKind::TakeAlways) {
Builder.createReleaseValue(Loc, SrcOp);
} else if (CCABI->getConsumptionKind() ==
CastConsumptionKind::TakeOnSuccess) {
// Insert a release in the success BB.
Builder.setInsertionPoint(SuccessBB->begin());
Builder.createReleaseValue(Loc, SrcOp);
}
}
// Results should be checked in case we process a conditional
// case. E.g. casts from NSArray into [SwiftType] may fail, i.e. return .None.
if (isConditional) {
// Copy the temporary into Dest.
// Load from the optional.
auto *SomeDecl = Builder.getASTContext().getOptionalSomeDecl(OTK);
SILBasicBlock *ConvSuccessBB = Inst->getFunction()->createBasicBlock();
SmallVector<std::pair<EnumElementDecl *, SILBasicBlock*>, 1> CaseBBs;
CaseBBs.push_back(std::make_pair(M.getASTContext().getOptionalNoneDecl(), FailureBB));
Builder.createSwitchEnumAddr(Loc, InOutOptionalParam, ConvSuccessBB, CaseBBs);
Builder.setInsertionPoint(FailureBB->begin());
Builder.createDeallocStack(Loc, Tmp);
Builder.setInsertionPoint(ConvSuccessBB);
auto Addr = Builder.createUncheckedTakeEnumDataAddr(Loc, InOutOptionalParam,
SomeDecl);
auto LoadFromOptional = Builder.createLoad(Loc, Addr);
// Store into Dest
Builder.createStore(Loc, LoadFromOptional, Dest);
Builder.createDeallocStack(Loc, Tmp);
SmallVector<SILValue, 1> SuccessBBArgs;
Builder.createBranch(Loc, SuccessBB, SuccessBBArgs);
}
EraseInstAction(Inst);
return (NewI) ? NewI : AI;
}
bool swift::isValidLinkageForFragileRef(SILLinkage linkage) {
switch (linkage) {
case SILLinkage::Private:
case SILLinkage::PrivateExternal:
case SILLinkage::Hidden:
case SILLinkage::HiddenExternal:
return false;
case SILLinkage::Shared:
case SILLinkage::SharedExternal:
// This handles some kind of generated functions, like constructors
// of clang imported types.
// TODO: check why those functions are not fragile anyway and make
// a less conservative check here.
return true;
case SILLinkage::Public:
case SILLinkage::PublicExternal:
return true;
}
}
/// Create a call of _bridgeToObjectiveC which converts an _ObjectiveCBridgeable
/// instance into a bridged ObjC type.
SILInstruction *
CastOptimizer::
optimizeBridgedSwiftToObjCCast(SILInstruction *Inst,
bool isConditional,
SILValue Src,
SILValue Dest,
CanType Source,
CanType Target,
Type BridgedSourceTy,
Type BridgedTargetTy,
SILBasicBlock *SuccessBB,
SILBasicBlock *FailureBB) {
auto &M = Inst->getModule();
auto Loc = Inst->getLoc();
// Find the _BridgedToObjectiveC protocol.
auto BridgedProto =
M.getASTContext().getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
auto Conf =
M.getSwiftModule()->lookupConformance(Source, BridgedProto, nullptr);
assert(Conf.getInt() == ConformanceKind::Conforms &&
"_ObjectiveCBridgeable conformance should exist");
(void) Conf;
bool isCurrentModuleBridgeToObjectiveC = false;
// Generate code to invoke _bridgeToObjectiveC
SILBuilderWithScope Builder(Inst);
auto Members = Source.getNominalOrBoundGenericNominal()->lookupDirect(
M.getASTContext().Id_bridgeToObjectiveC);
assert(Members.size() == 1 &&
"There should be exactly one implementation of _bridgeToObjectiveC");
auto BridgeFuncDecl = Members.front();
auto BridgeFuncDeclRef = SILDeclRef(BridgeFuncDecl);
Module *Mod = M.getASTContext().getLoadedModule(
M.getASTContext().Id_Foundation);
if (!Mod)
return nullptr;
SmallVector<ValueDecl *, 2> Results;
Mod->lookupMember(Results, Source.getNominalOrBoundGenericNominal(),
M.getASTContext().Id_bridgeToObjectiveC, Identifier());
ArrayRef<ValueDecl *> ResultsRef(Results);
if (ResultsRef.empty()) {
M.getSwiftModule()->lookupMember(Results, Source.getNominalOrBoundGenericNominal(),
M.getASTContext().Id_bridgeToObjectiveC, Identifier());
ResultsRef = Results;
isCurrentModuleBridgeToObjectiveC = true;
}
if (ResultsRef.size() != 1)
return nullptr;
auto MemberDeclRef = SILDeclRef(Results.front());
auto Linkage = (isCurrentModuleBridgeToObjectiveC)
? ForDefinition_t::ForDefinition
: ForDefinition_t::NotForDefinition;
auto *BridgedFunc = M.getOrCreateFunction(Loc, MemberDeclRef, Linkage);
assert(BridgedFunc &&
"Implementation of _bridgeToObjectiveC could not be found");
if (Inst->getFunction()->isFragile() &&
!(BridgedFunc->isFragile() ||
isValidLinkageForFragileRef(BridgedFunc->getLinkage()) ||
BridgedFunc->isExternalDeclaration()))
return nullptr;
auto ParamTypes = BridgedFunc->getLoweredFunctionType()
->getParametersWithoutIndirectResult();
auto SILFnTy = SILType::getPrimitiveObjectType(
M.Types.getConstantFunctionType(BridgeFuncDeclRef));
ArrayRef<Substitution> Subs;
if (Source.getNominalOrBoundGenericNominal()->getGenericSignature()) {
// Get substitutions, if source is a bound generic type.
Subs = Source->castTo<BoundGenericType>()->getSubstitutions(
M.getSwiftModule(), nullptr);
}
SILType SubstFnTy = SILFnTy.substGenericArgs(M, Subs);
SILType ResultTy = SubstFnTy.castTo<SILFunctionType>()->getSILResult();
auto FnRef = Builder.createFunctionRef(Loc, BridgedFunc);
if (Src->getType().isAddress()) {
// Create load
Src = Builder.createLoad(Loc, Src);
}
if(ParamTypes[0].getConvention() == ParameterConvention::Direct_Guaranteed)
Builder.createRetainValue(Loc, Src);
// Generate a code to invoke the bridging function.
auto *NewAI = Builder.createApply(Loc, FnRef, SubstFnTy, ResultTy, Subs, Src,
false);
if(ParamTypes[0].getConvention() == ParameterConvention::Direct_Guaranteed)
Builder.createReleaseValue(Loc, Src);
SILInstruction *NewI = NewAI;
if (Dest) {
// If it is addr cast then store the result.
auto ConvTy = NewAI->getType();
auto DestTy = Dest->getType().getObjectType();
assert((ConvTy == DestTy || DestTy.isSuperclassOf(ConvTy)) &&
"Destination should have the same type or be a superclass "
"of the source operand");
auto CastedValue = SILValue(
(ConvTy == DestTy) ? NewI : Builder.createUpcast(Loc, NewAI, DestTy));
NewI = Builder.createStore(Loc, CastedValue, Dest);
}
if (Dest) {
EraseInstAction(Inst);
}
return NewI;
}
/// Make use of the fact that some of these casts cannot fail.
/// For example, if the ObjC type is exactly the expected
/// _ObjectiveCType type, then it would always succeed for
/// NSString, NSNumber, etc.
/// Casts from NSArray, NSDictionary and NSSet may fail.
///
/// If ObjC class is not exactly _ObjectiveCType, then
/// its conversion to a required _ObjectiveCType may fail.
SILInstruction *
CastOptimizer::
optimizeBridgedCasts(SILInstruction *Inst,
bool isConditional,
SILValue Src,
SILValue Dest,
CanType source,
CanType target,
SILBasicBlock *SuccessBB,
SILBasicBlock *FailureBB) {
auto &M = Inst->getModule();
// To apply the bridged optimizations, we should
// ensure that types are not existential,
// and that one of the types is a class and another
// one is a struct.
if (source.isAnyExistentialType() ||
target.isAnyExistentialType() ||
(source.getClassOrBoundGenericClass() &&
!target.getStructOrBoundGenericStruct()) ||
(target.getClassOrBoundGenericClass() &&
!source.getStructOrBoundGenericStruct()))
return nullptr;
// Casts involving non-bound generic types cannot be optimized.
if (source->hasArchetype() || target->hasArchetype())
return nullptr;
auto BridgedTargetTy = getCastFromObjC(M, source, target);
if (!BridgedTargetTy)
return nullptr;
auto BridgedSourceTy = getCastFromObjC(M, target, source);
CanType CanBridgedTargetTy(BridgedTargetTy);
CanType CanBridgedSourceTy(BridgedSourceTy);
if (CanBridgedSourceTy == source && CanBridgedTargetTy == target) {
// Both source and target type are ObjC types.
return nullptr;
}
if (CanBridgedSourceTy != source && CanBridgedTargetTy != target) {
// Both source and target type are Swift types.
return nullptr;
}
if (CanBridgedSourceTy || CanBridgedTargetTy) {
// Check what kind of conversion it is? ObjC->Swift or Swift-ObjC?
if (CanBridgedTargetTy != target) {
// This is an ObjC to Swift cast.
return optimizeBridgedObjCToSwiftCast(Inst, isConditional, Src, Dest, source,
target, BridgedSourceTy, BridgedTargetTy, SuccessBB, FailureBB);
} else {
// This is a Swift to ObjC cast
return optimizeBridgedSwiftToObjCCast(Inst, isConditional, Src, Dest, source,
target, BridgedSourceTy, BridgedTargetTy, SuccessBB, FailureBB);
}
}
llvm_unreachable("Unknown kind of bridging");
}
SILInstruction *
CastOptimizer::
simplifyCheckedCastAddrBranchInst(CheckedCastAddrBranchInst *Inst) {
if (auto *I = optimizeCheckedCastAddrBranchInst(Inst))
Inst = dyn_cast<CheckedCastAddrBranchInst>(I);
if (!Inst)
return nullptr;
auto Loc = Inst->getLoc();
auto Src = Inst->getSrc();
auto Dest = Inst->getDest();
auto SourceType = Inst->getSourceType();
auto TargetType = Inst->getTargetType();
auto *SuccessBB = Inst->getSuccessBB();
auto *FailureBB = Inst->getFailureBB();
auto &Mod = Inst->getModule();
SILBuilderWithScope Builder(Inst);
// Try to determine the outcome of the cast from a known type
// to a protocol type at compile-time.
bool isSourceTypeExact = isa<MetatypeInst>(Inst->getSrc());
// Check if we can statically predict the outcome of the cast.
auto Feasibility = classifyDynamicCast(Mod.getSwiftModule(),
Src->getType().getSwiftRValueType(),
Dest->getType().getSwiftRValueType(),
isSourceTypeExact,
Mod.isWholeModule());
if (Feasibility == DynamicCastFeasibility::MaySucceed) {
return nullptr;
}
if (Feasibility == DynamicCastFeasibility::WillFail) {
if (shouldDestroyOnFailure(Inst->getConsumptionKind())) {
auto &srcTL = Builder.getModule().getTypeLowering(Src->getType());
srcTL.emitDestroyAddress(Builder, Loc, Src);
}
auto NewI = Builder.createBranch(Loc, FailureBB);
EraseInstAction(Inst);
WillFailAction();
return NewI;
}
// Cast will succeed
// Replace by unconditional_addr_cast, followed by a branch.
// The unconditional_addr_cast can be skipped, if the result of a cast
// is not used afterwards.
bool ResultNotUsed = isa<AllocStackInst>(Dest);
for (auto Use : Dest->getUses()) {
auto *User = Use->getUser();
if (isa<DeallocStackInst>(User) || User == Inst)
continue;
ResultNotUsed = false;
break;
}
auto *BB = Inst->getParent();
if (!ResultNotUsed) {
SILInstruction *BridgedI = nullptr;
// To apply the bridged optimizations, we should
// ensure that types are not existential,
// and that not both types are classes.
BridgedI = optimizeBridgedCasts(Inst, true, Src, Dest, SourceType,
TargetType, SuccessBB, FailureBB);
if (!BridgedI) {
// Since it is an addr cast, only address types are handled here.
if (!Src->getType().isAddress() || !Dest->getType().isAddress()) {
return nullptr;
} else if (!emitSuccessfulIndirectUnconditionalCast(
Builder, Mod.getSwiftModule(), Loc,
Inst->getConsumptionKind(), Src, SourceType, Dest,
TargetType, Inst)) {
// No optimization was possible.
return nullptr;
}
EraseInstAction(Inst);
}
SILInstruction *NewI = &BB->back();
if (!isa<TermInst>(NewI)) {
Builder.setInsertionPoint(BB);
NewI = Builder.createBranch(Loc, SuccessBB);
}
WillSucceedAction();
return NewI;
} else {
// Result is not used.
EraseInstAction(Inst);
Builder.setInsertionPoint(BB);
auto *NewI = Builder.createBranch(Loc, SuccessBB);
WillSucceedAction();
return NewI;
}
}
SILInstruction *
CastOptimizer::simplifyCheckedCastBranchInst(CheckedCastBranchInst *Inst) {
if (Inst->isExact()) {
auto *ARI = dyn_cast<AllocRefInst>(stripUpCasts(Inst->getOperand()));
if (!ARI)
return nullptr;
// We know the dynamic type of the operand.
SILBuilderWithScope Builder(Inst);
auto Loc = Inst->getLoc();
auto *SuccessBB = Inst->getSuccessBB();
auto *FailureBB = Inst->getFailureBB();
if (ARI->getType() == Inst->getCastType()) {
// This exact cast will succeed.
SmallVector<SILValue, 1> Args;
Args.push_back(ARI);
auto *NewI = Builder.createBranch(Loc, SuccessBB, Args);
EraseInstAction(Inst);
WillSucceedAction();
return NewI;
}
// This exact cast will fail.
auto *NewI = Builder.createBranch(Loc, FailureBB);
EraseInstAction(Inst);
WillFailAction();
return NewI;
}
if (auto *I = optimizeCheckedCastBranchInst(Inst))
Inst = dyn_cast<CheckedCastBranchInst>(I);
if (!Inst)
return nullptr;
auto LoweredSourceType = Inst->getOperand()->getType();
auto LoweredTargetType = Inst->getCastType();
auto SourceType = LoweredSourceType.getSwiftRValueType();
auto TargetType = LoweredTargetType.getSwiftRValueType();
auto Loc = Inst->getLoc();
auto *SuccessBB = Inst->getSuccessBB();
auto *FailureBB = Inst->getFailureBB();
auto Op = Inst->getOperand();
auto &Mod = Inst->getModule();
bool isSourceTypeExact = isa<MetatypeInst>(Op);
// Check if we can statically predict the outcome of the cast.
auto Feasibility = classifyDynamicCast(Mod.getSwiftModule(),
SourceType,
TargetType,
isSourceTypeExact);
if (Feasibility == DynamicCastFeasibility::MaySucceed) {
return nullptr;
}
SILBuilderWithScope Builder(Inst);
if (Feasibility == DynamicCastFeasibility::WillFail) {
auto *NewI = Builder.createBranch(Loc, FailureBB);
EraseInstAction(Inst);
WillFailAction();
return NewI;
}
// Casting will succeed.
// Replace by unconditional_cast, followed by a branch.
// The unconditional_cast can be skipped, if the result of a cast
// is not used afterwards.
bool ResultNotUsed = SuccessBB->getBBArg(0)->use_empty();
SILValue CastedValue;
if (Op->getType() != LoweredTargetType) {
if (!ResultNotUsed) {
auto Src = Inst->getOperand();
auto Dest = SILValue();
// To apply the bridged casts optimizations.
auto BridgedI = optimizeBridgedCasts(Inst, false, Src, Dest, SourceType,
TargetType, nullptr, nullptr);
if (BridgedI) {
CastedValue = BridgedI;
} else {
if (!canUseScalarCheckedCastInstructions(Mod, SourceType, TargetType))
return nullptr;
CastedValue = emitSuccessfulScalarUnconditionalCast(
Builder, Mod.getSwiftModule(), Loc, Op, LoweredTargetType,
SourceType, TargetType, Inst);
}
if (!CastedValue)
CastedValue =
Builder.createUnconditionalCheckedCast(Loc, Op, LoweredTargetType);
} else {
CastedValue = SILUndef::get(LoweredTargetType, Mod);
}
} else {
// No need to cast.
CastedValue = Op;
}
auto *NewI = Builder.createBranch(Loc, SuccessBB, CastedValue);
EraseInstAction(Inst);
WillSucceedAction();
return NewI;
}
SILInstruction *
CastOptimizer::
optimizeCheckedCastAddrBranchInst(CheckedCastAddrBranchInst *Inst) {
auto Loc = Inst->getLoc();
auto Src = Inst->getSrc();
auto Dest = Inst->getDest();
auto *SuccessBB = Inst->getSuccessBB();
auto *FailureBB = Inst->getFailureBB();
// If there is an unbound generic type involved in the cast, bail.
if (Src->getType().hasArchetype() || Dest->getType().hasArchetype())
return nullptr;
// %1 = metatype $A.Type
// [%2 = init_existential_metatype %1 ...]
// %3 = alloc_stack
// store %1 to %3 or store %2 to %3
// checked_cast_addr_br %3 to ...
// ->
// %1 = metatype $A.Type
// %c = checked_cast_br %1 to ...
// store %c to %3 (if successful)
if (auto *ASI = dyn_cast<AllocStackInst>(Src)) {
// Check if the value of this alloc_stack is set only once by a store
// instruction, used only by CCABI and then deallocated.
bool isLegal = true;
StoreInst *Store = nullptr;
for (auto Use : ASI->getUses()) {
auto *User = Use->getUser();
if (isa<DeallocStackInst>(User) || User == Inst)
continue;
if (auto *SI = dyn_cast<StoreInst>(User)) {
if (!Store) {
Store = SI;
continue;
}
}
isLegal = false;
break;
}
if (isLegal && Store) {
// Check what was the value stored in the allocated stack slot.
auto Src = Store->getSrc();
MetatypeInst *MI = nullptr;
if (auto *IEMI = dyn_cast<InitExistentialMetatypeInst>(Src)) {
MI = dyn_cast<MetatypeInst>(IEMI->getOperand());
}
if (!MI)
MI = dyn_cast<MetatypeInst>(Src);
if (MI) {
if (SuccessBB->getSinglePredecessor()
&& canUseScalarCheckedCastInstructions(Inst->getModule(),
MI->getType().getSwiftRValueType(),
Dest->getType().getObjectType().getSwiftRValueType())) {
SILBuilderWithScope B(Inst);
auto NewI = B.createCheckedCastBranch(
Loc, false /*isExact*/, MI,
Dest->getType().getObjectType(), SuccessBB, FailureBB);
SuccessBB->createBBArg(Dest->getType().getObjectType(), nullptr);
B.setInsertionPoint(SuccessBB->begin());
// Store the result
B.createStore(Loc, SuccessBB->getBBArg(0), Dest);
EraseInstAction(Inst);
return NewI;
}
}
}
}
return nullptr;
}
SILInstruction *
CastOptimizer::optimizeCheckedCastBranchInst(CheckedCastBranchInst *Inst) {
if (Inst->isExact())
return nullptr;
auto LoweredTargetType = Inst->getCastType();
auto Loc = Inst->getLoc();
auto *SuccessBB = Inst->getSuccessBB();
auto *FailureBB = Inst->getFailureBB();
auto Op = Inst->getOperand();
// Try to simplify checked_cond_br instructions using existential
// metatypes by propagating a concrete type whenever it can be
// determined statically.
// %0 = metatype $A.Type
// %1 = init_existential_metatype ..., %0: $A
// checked_cond_br %1, ....
// ->
// %1 = metatype $A.Type
// checked_cond_br %1, ....
if (auto *IEMI = dyn_cast<InitExistentialMetatypeInst>(Op)) {
if (auto *MI = dyn_cast<MetatypeInst>(IEMI->getOperand())) {
SILBuilderWithScope B(Inst);
auto *NewI = B.createCheckedCastBranch(Loc, /* isExact */ false, MI,
LoweredTargetType,
SuccessBB,
FailureBB);
EraseInstAction(Inst);
return NewI;
}
}
if (auto *EMI = dyn_cast<ExistentialMetatypeInst>(Op)) {
// Operand of the existential_metatype instruction.
auto Op = EMI->getOperand();
auto EmiTy = EMI->getType();
// %0 = alloc_stack ..
// %1 = init_existential_addr %0: $A
// %2 = existential_metatype %0, ...
// checked_cond_br %2, ....
// ->
// %1 = metatype $A.Type
// checked_cond_br %1, ....
if (auto *ASI = dyn_cast<AllocStackInst>(Op)) {
// Should be in the same BB.
if (ASI->getParent() != EMI->getParent())
return nullptr;
// Check if this alloc_stack is only initialized once by means of
// single init_existential_addr.
bool isLegal = true;
// init_existential instruction used to initialize this alloc_stack.
InitExistentialAddrInst *FoundIEI = nullptr;
for (auto Use: getNonDebugUses(ASI)) {
auto *User = Use->getUser();
if (isa<ExistentialMetatypeInst>(User) ||
isa<DestroyAddrInst>(User) ||
isa<DeallocStackInst>(User))
continue;
if (auto *IEI = dyn_cast<InitExistentialAddrInst>(User)) {
if (!FoundIEI) {
FoundIEI = IEI;
continue;
}
}
isLegal = false;
break;
}
if (isLegal && FoundIEI) {
// Should be in the same BB.
if (FoundIEI->getParent() != EMI->getParent())
return nullptr;
// Get the type used to initialize the existential.
auto LoweredConcreteTy = FoundIEI->getLoweredConcreteType();
if (LoweredConcreteTy.isAnyExistentialType())
return nullptr;
// Get the metatype of this type.
auto EMT = dyn_cast<AnyMetatypeType>(EmiTy.getSwiftRValueType());
auto *MetaTy = MetatypeType::get(LoweredConcreteTy.getSwiftRValueType(),
EMT->getRepresentation());
auto CanMetaTy = CanMetatypeType::CanTypeWrapper(MetaTy);
auto SILMetaTy = SILType::getPrimitiveObjectType(CanMetaTy);
SILBuilderWithScope B(Inst);
auto *MI = B.createMetatype(FoundIEI->getLoc(), SILMetaTy);
auto *NewI = B.createCheckedCastBranch(Loc, /* isExact */ false, MI,
LoweredTargetType,
SuccessBB,
FailureBB);
EraseInstAction(Inst);
return NewI;
}
}
// %0 = alloc_ref $A
// %1 = init_existential_ref %0: $A, $...
// %2 = existential_metatype ..., %1 : ...
// checked_cond_br %2, ....
// ->
// %1 = metatype $A.Type
// checked_cond_br %1, ....
if (auto *FoundIERI = dyn_cast<InitExistentialRefInst>(Op)) {
auto *ASRI = dyn_cast<AllocRefInst>(FoundIERI->getOperand());
if (!ASRI)
return nullptr;
// Should be in the same BB.
if (ASRI->getParent() != EMI->getParent())
return nullptr;
// Check if this alloc_stack is only initialized once by means of
// a single init_existential_ref.
bool isLegal = true;
for (auto Use: getNonDebugUses(ASRI)) {
auto *User = Use->getUser();
if (isa<ExistentialMetatypeInst>(User) || isa<StrongReleaseInst>(User))
continue;
if (auto *IERI = dyn_cast<InitExistentialRefInst>(User)) {
if (IERI == FoundIERI) {
continue;
}
}
isLegal = false;
break;
}
if (isLegal && FoundIERI) {
// Should be in the same BB.
if (FoundIERI->getParent() != EMI->getParent())
return nullptr;
// Get the type used to initialize the existential.
auto ConcreteTy = FoundIERI->getFormalConcreteType();
if (ConcreteTy.isAnyExistentialType())
return nullptr;
// Get the SIL metatype of this type.
auto EMT = dyn_cast<AnyMetatypeType>(EMI->getType().getSwiftRValueType());
auto *MetaTy = MetatypeType::get(ConcreteTy, EMT->getRepresentation());
auto CanMetaTy = CanMetatypeType::CanTypeWrapper(MetaTy);
auto SILMetaTy = SILType::getPrimitiveObjectType(CanMetaTy);
SILBuilderWithScope B(Inst);
auto *MI = B.createMetatype(FoundIERI->getLoc(), SILMetaTy);
auto *NewI = B.createCheckedCastBranch(Loc, /* isExact */ false, MI,
LoweredTargetType,
SuccessBB,
FailureBB);
EraseInstAction(Inst);
return NewI;
}
}
}
return nullptr;
}
ValueBase *
CastOptimizer::
optimizeUnconditionalCheckedCastInst(UnconditionalCheckedCastInst *Inst) {
auto LoweredSourceType = Inst->getOperand()->getType();
auto LoweredTargetType = Inst->getType();
auto Loc = Inst->getLoc();
auto Op = Inst->getOperand();
auto &Mod = Inst->getModule();
bool isSourceTypeExact = isa<MetatypeInst>(Op);
// Check if we can statically predict the outcome of the cast.
auto Feasibility = classifyDynamicCast(Mod.getSwiftModule(),
LoweredSourceType.getSwiftRValueType(),
LoweredTargetType.getSwiftRValueType(),
isSourceTypeExact);
if (Feasibility == DynamicCastFeasibility::MaySucceed) {
return nullptr;
}
if (Feasibility == DynamicCastFeasibility::WillFail) {
// Remove the cast and insert a trap, followed by an
// unreachable instruction.
SILBuilderWithScope Builder(Inst);
auto *Trap = Builder.createBuiltinTrap(Loc);
Inst->replaceAllUsesWithUndef();
EraseInstAction(Inst);
Builder.setInsertionPoint(std::next(SILBasicBlock::iterator(Trap)));
Builder.createUnreachable(ArtificialUnreachableLocation());
WillFailAction();
return Trap;
}
if (Feasibility == DynamicCastFeasibility::WillSucceed) {
if (Inst->use_empty()) {
EraseInstAction(Inst);
WillSucceedAction();
return nullptr;
}
SILBuilderWithScope Builder(Inst);
// Try to apply the bridged casts optimizations
auto SourceType = LoweredSourceType.getSwiftRValueType();
auto TargetType = LoweredTargetType.getSwiftRValueType();
auto Src = Inst->getOperand();
auto NewI = optimizeBridgedCasts(Inst, false, Src, SILValue(), SourceType,
TargetType, nullptr, nullptr);
if (NewI) {
ReplaceInstUsesAction(Inst, NewI);
EraseInstAction(Inst);
WillSucceedAction();
return NewI;
}
if (isBridgingCast(SourceType, TargetType))
return nullptr;
auto Result = emitSuccessfulScalarUnconditionalCast(Builder,
Mod.getSwiftModule(), Loc, Op,
LoweredTargetType,
LoweredSourceType.getSwiftRValueType(),
LoweredTargetType.getSwiftRValueType(),
Inst);
if (!Result) {
// No optimization was possible.
return nullptr;
}
ReplaceInstUsesAction(Inst, Result);
EraseInstAction(Inst);
WillSucceedAction();
return Result;
}
return nullptr;
}
SILInstruction *
CastOptimizer::
optimizeUnconditionalCheckedCastAddrInst(UnconditionalCheckedCastAddrInst *Inst) {
auto Loc = Inst->getLoc();
auto Src = Inst->getSrc();
auto Dest = Inst->getDest();
auto SourceType = Inst->getSourceType();
auto TargetType = Inst->getTargetType();
auto &Mod = Inst->getModule();
bool isSourceTypeExact = isa<MetatypeInst>(Src);
// Check if we can statically predict the outcome of the cast.
auto Feasibility = classifyDynamicCast(Mod.getSwiftModule(), SourceType,
TargetType, isSourceTypeExact);
if (Feasibility == DynamicCastFeasibility::MaySucceed) {
// Forced bridged casts can be still simplified here.
// If they fail, they fail inside the conversion function.
if (!isBridgingCast(SourceType, TargetType))
return nullptr;
}
if (Feasibility == DynamicCastFeasibility::WillFail) {
// Remove the cast and insert a trap, followed by an
// unreachable instruction.
SILBuilderWithScope Builder(Inst);
SILInstruction *NewI = Builder.createBuiltinTrap(Loc);
// mem2reg's invariants get unhappy if we don't try to
// initialize a loadable result.
auto DestType = Dest->getType();
auto &resultTL = Mod.Types.getTypeLowering(DestType);
if (!resultTL.isAddressOnly()) {
auto undef = SILValue(SILUndef::get(DestType.getObjectType(),
Builder.getModule()));
NewI = Builder.createStore(Loc, undef, Dest);
}
Inst->replaceAllUsesWithUndef();
EraseInstAction(Inst);
Builder.setInsertionPoint(std::next(SILBasicBlock::iterator(NewI)));
Builder.createUnreachable(ArtificialUnreachableLocation());
WillFailAction();
}
if (Feasibility == DynamicCastFeasibility::WillSucceed ||
Feasibility == DynamicCastFeasibility::MaySucceed) {
bool ResultNotUsed = isa<AllocStackInst>(Dest);
for (auto Use : Dest->getUses()) {
auto *User = Use->getUser();
if (isa<DeallocStackInst>(User) || User == Inst)
continue;
ResultNotUsed = false;
break;
}
if (ResultNotUsed) {
EraseInstAction(Inst);
WillSucceedAction();
return nullptr;
}
// Try to apply the bridged casts optimizations
auto NewI = optimizeBridgedCasts(Inst, false, Src, Dest, SourceType,
TargetType, nullptr, nullptr);
if (NewI) {
WillSucceedAction();
return nullptr;
}
if (isBridgingCast(SourceType, TargetType))
return nullptr;
SILBuilderWithScope Builder(Inst);
if (!emitSuccessfulIndirectUnconditionalCast(Builder, Mod.getSwiftModule(),
Loc, Inst->getConsumptionKind(),
Src, SourceType,
Dest, TargetType, Inst)) {
// No optimization was possible.
return nullptr;
}
Inst->replaceAllUsesWithUndef();
EraseInstAction(Inst);
WillSucceedAction();
}
return nullptr;
}
bool swift::simplifyUsers(SILInstruction *I) {
bool Changed = false;
for (auto UI = I->use_begin(), UE = I->use_end(); UI != UE; ) {
SILInstruction *User = UI->getUser();
++UI;
if (!User->hasValue())
continue;
SILValue S = simplifyInstruction(User);
if (!S)
continue;
User->replaceAllUsesWith(S);
User->eraseFromParent();
Changed = true;
}
return Changed;
}
/// Some support functions for the global-opt and let-properties-opts
/// Check if a given type is a simple type, i.e. a builtin
/// integer or floating point type or a struct/tuple whose members
/// are of simple types.
/// TODO: Cache the "simple" flag for types to avoid repeating checks.
bool swift::isSimpleType(SILType SILTy, SILModule& Module) {
// Classes can never be initialized statically at compile-time.
if (SILTy.getClassOrBoundGenericClass()) {
return false;
}
if (!SILTy.isTrivial(Module))
return false;
return true;
}
/// Check if the value of V is computed by means of a simple initialization.
/// Store the actual SILValue into Val and the reversed list of instructions
/// initializing it in Insns.
/// The check is performed by recursively walking the computation of the
/// SIL value being analyzed.
/// TODO: Move into utils.
bool
swift::analyzeStaticInitializer(SILValue V,
SmallVectorImpl<SILInstruction *> &Insns) {
auto I = dyn_cast<SILInstruction>(V);
if (!I)
return false;
while (true) {
if (!isa<AllocGlobalInst>(I))
Insns.push_back(I);
if (auto *SI = dyn_cast<StructInst>(I)) {
// If it is not a struct which is a simple type, bail.
if (!isSimpleType(SI->getType(), I->getModule()))
return false;
for (auto &Op: SI->getAllOperands()) {
// If one of the struct instruction operands is not
// a simple initializer, bail.
if (!analyzeStaticInitializer(Op.get(), Insns))
return false;
}
return true;
} if (auto *TI = dyn_cast<TupleInst>(I)) {
// If it is not a tuple which is a simple type, bail.
if (!isSimpleType(TI->getType(), I->getModule()))
return false;
for (auto &Op: TI->getAllOperands()) {
// If one of the struct instruction operands is not
// a simple initializer, bail.
if (!analyzeStaticInitializer(Op.get(), Insns))
return false;
}
return true;
} else {
if (auto *bi = dyn_cast<BuiltinInst>(I)) {
switch (bi->getBuiltinInfo().ID) {
case BuiltinValueKind::FPTrunc:
if (auto *LI = dyn_cast<LiteralInst>(bi->getArguments()[0])) {
I = LI;
continue;
}
break;
default:
return false;
}
}
if (I->getKind() == ValueKind::IntegerLiteralInst
|| I->getKind() == ValueKind::FloatLiteralInst
|| I->getKind() == ValueKind::StringLiteralInst)
return true;
return false;
}
}
return false;
}
/// Replace load sequence which may contain
/// a chain of struct_element_addr followed by a load.
/// The sequence is traversed inside out, i.e.
/// starting with the innermost struct_element_addr
/// Move into utils.
void swift::replaceLoadSequence(SILInstruction *I,
SILInstruction *Value,
SILBuilder &B) {
if (auto *LI = dyn_cast<LoadInst>(I)) {
LI->replaceAllUsesWith(Value);
return;
}
// It is a series of struct_element_addr followed by load.
if (auto *SEAI = dyn_cast<StructElementAddrInst>(I)) {
auto *SEI = B.createStructExtract(SEAI->getLoc(), Value, SEAI->getField());
for (auto SEAIUse : SEAI->getUses()) {
replaceLoadSequence(SEAIUse->getUser(), SEI, B);
}
return;
}
if (auto *TEAI = dyn_cast<TupleElementAddrInst>(I)) {
auto *TEI = B.createTupleExtract(TEAI->getLoc(), Value, TEAI->getFieldNo());
for (auto TEAIUse : TEAI->getUses()) {
replaceLoadSequence(TEAIUse->getUser(), TEI, B);
}
return;
}
llvm_unreachable("Unknown instruction sequence for reading from a global");
}
/// Are the callees that could be called through Decl statically
/// knowable based on the Decl and the compilation mode?
bool swift::calleesAreStaticallyKnowable(SILModule &M, SILDeclRef Decl) {
if (Decl.isForeign)
return false;
const DeclContext *AssocDC = M.getAssociatedContext();
if (!AssocDC)
return false;
auto *AFD = Decl.getAbstractFunctionDecl();
assert(AFD && "Expected abstract function decl!");
// Only handle members defined within the SILModule's associated context.
if (!AFD->isChildContextOf(AssocDC))
return false;
if (AFD->isDynamic())
return false;
if (!AFD->hasAccessibility())
return false;
// Only consider 'private' members, unless we are in whole-module compilation.
switch (AFD->getEffectiveAccess()) {
case Accessibility::Public:
return false;
case Accessibility::Internal:
return M.isWholeModule();
case Accessibility::Private:
return true;
}
}
void swift::hoistAddressProjections(Operand &Op, SILInstruction *InsertBefore,
DominanceInfo *DomTree) {
SILValue V = Op.get();
SILInstruction *Prev = nullptr;
auto *InsertPt = InsertBefore;
while (true) {
SILValue Incoming = stripSinglePredecessorArgs(V);
// Forward the incoming arg from a single predecessor.
if (V != Incoming) {
if (V == Op.get()) {
// If we are the operand itself set the operand to the incoming
// argument.
Op.set(Incoming);
V = Incoming;
} else {
// Otherwise, set the previous projections operand to the incoming
// argument.
assert(Prev && "Must have seen a projection");
Prev->setOperand(0, Incoming);
V = Incoming;
}
}
switch (V->getKind()) {
case ValueKind::StructElementAddrInst:
case ValueKind::TupleElementAddrInst:
case ValueKind::RefElementAddrInst:
case ValueKind::UncheckedTakeEnumDataAddrInst: {
auto *Inst = cast<SILInstruction>(V);
// We are done once the current projection dominates the insert point.
if (DomTree->dominates(Inst->getParent(), InsertBefore->getParent()))
return;
// Move the current projection and memorize it for the next iteration.
Prev = Inst;
Inst->moveBefore(InsertPt);
InsertPt = Inst;
V = Inst->getOperand(0);
continue;
}
default:
assert(DomTree->dominates(V->getParentBB(), InsertBefore->getParent()) &&
"The projected value must dominate the insertion point");
return;
}
}
}
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