Google Git
Sign in
fuchsia / third_party / swift / 1862c95a58d6461091e849224696b3e35cd13dcf / . / lib / SILOptimizer / Utils / InstOptUtils.cpp
blob: 76f6d6551364bca277c0dc1494099a2c212d0ae0 [file] [log] [blame]
//===--- InstOptUtils.cpp - SILOptimizer instruction utilities ------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#include "swift/SILOptimizer/Utils/InstOptUtils.h"
#include "swift/AST/GenericSignature.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/SIL/BasicBlockUtils.h"
#include "swift/SIL/DebugUtils.h"
#include "swift/SIL/DynamicCasts.h"
#include "swift/SIL/InstructionUtils.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/SILOptimizer/Analysis/ARCAnalysis.h"
#include "swift/SILOptimizer/Analysis/Analysis.h"
#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
#include "swift/SILOptimizer/Utils/CFGOptUtils.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 "llvm/Support/Compiler.h"
#include <deque>
using namespace swift;
static llvm::cl::opt<bool> EnableExpandAll("enable-expand-all",
llvm::cl::init(false));
/// Creates an increment on \p Ptr before insertion point \p InsertPt that
/// creates a strong_retain if \p Ptr has reference semantics itself or a
/// retain_value if \p Ptr is a non-trivial value without reference-semantics.
NullablePtr<SILInstruction>
swift::createIncrementBefore(SILValue ptr, SILInstruction *insertPt) {
// Set up the builder we use to insert at our insertion point.
SILBuilder builder(insertPt);
auto loc = RegularLocation::getAutoGeneratedLocation();
// If we have a trivial type, just bail, there is no work to do.
if (ptr->getType().isTrivial(builder.getFunction()))
return nullptr;
// If Ptr is refcounted itself, create the strong_retain and
// return.
if (ptr->getType().isReferenceCounted(builder.getModule())) {
if (ptr->getType().is<UnownedStorageType>())
return builder.createUnownedRetain(loc, ptr,
builder.getDefaultAtomicity());
else
return builder.createStrongRetain(loc, ptr,
builder.getDefaultAtomicity());
}
// Otherwise, create the retain_value.
return builder.createRetainValue(loc, ptr, builder.getDefaultAtomicity());
}
/// Creates a decrement on \p ptr before insertion point \p InsertPt that
/// creates a strong_release if \p ptr has reference semantics itself or
/// a release_value if \p ptr is a non-trivial value without
/// reference-semantics.
NullablePtr<SILInstruction>
swift::createDecrementBefore(SILValue ptr, SILInstruction *insertPt) {
// Setup the builder we will use to insert at our insertion point.
SILBuilder builder(insertPt);
auto loc = RegularLocation::getAutoGeneratedLocation();
if (ptr->getType().isTrivial(builder.getFunction()))
return nullptr;
// If ptr has reference semantics itself, create a strong_release.
if (ptr->getType().isReferenceCounted(builder.getModule())) {
if (ptr->getType().is<UnownedStorageType>())
return builder.createUnownedRelease(loc, ptr,
builder.getDefaultAtomicity());
else
return builder.createStrongRelease(loc, ptr,
builder.getDefaultAtomicity());
}
// Otherwise create a release value.
return builder.createReleaseValue(loc, ptr, builder.getDefaultAtomicity());
}
/// 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 *inst) {
// At Onone, consider all uses, including the debug_info.
// This way, debug_info is preserved at Onone.
if (inst->hasUsesOfAnyResult()
&& inst->getFunction()->getEffectiveOptimizationMode()
<= OptimizationMode::NoOptimization)
return false;
if (!onlyHaveDebugUsesOfAllResults(inst) || isa<TermInst>(inst))
return false;
if (auto *bi = dyn_cast<BuiltinInst>(inst)) {
// Although the onFastPath builtin has no side-effects we don't want to
// remove it.
if (bi->getBuiltinInfo().ID == BuiltinValueKind::OnFastPath)
return false;
return !bi->mayHaveSideEffects();
}
// condfail instructions that obviously can't fail are dead.
if (auto *cfi = dyn_cast<CondFailInst>(inst))
if (auto *ili = dyn_cast<IntegerLiteralInst>(cfi->getOperand()))
if (!ili->getValue())
return true;
// mark_uninitialized is never dead.
if (isa<MarkUninitializedInst>(inst))
return false;
if (isa<DebugValueInst>(inst) || isa<DebugValueAddrInst>(inst))
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>(inst))
return true;
if (!inst->mayHaveSideEffects())
return true;
return false;
}
/// Return true if this is a release instruction and the released value
/// is a part of a guaranteed parameter.
bool swift::isIntermediateRelease(SILInstruction *inst,
EpilogueARCFunctionInfo *eafi) {
// Check whether this is a release instruction.
if (!isa<StrongReleaseInst>(inst) && !isa<ReleaseValueInst>(inst))
return false;
// OK. we have a release instruction.
// Check whether this is a release on part of a guaranteed function argument.
SILValue Op = stripValueProjections(inst->getOperand(0));
auto *arg = dyn_cast<SILFunctionArgument>(Op);
if (!arg)
return false;
// This is a release on a guaranteed parameter. Its not the final release.
if (arg->hasConvention(SILArgumentConvention::Direct_Guaranteed))
return true;
// This is a release on an owned parameter and its not the epilogue release.
// Its not the final release.
auto rel = eafi->computeEpilogueARCInstructions(
EpilogueARCContext::EpilogueARCKind::Release, arg);
if (rel.size() && !rel.count(inst))
return true;
// Failed to prove anything.
return false;
}
namespace {
using CallbackTy = llvm::function_ref<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 *inst : ia) {
// If the instruction is not dead and force is false, do nothing.
if (force || isInstructionTriviallyDead(inst))
deadInsts.insert(inst);
}
llvm::SmallPtrSet<SILInstruction *, 8> nextInsts;
while (!deadInsts.empty()) {
for (auto inst : deadInsts) {
// Call the callback before we mutate the to be deleted instruction in any
// way.
callback(inst);
// Check if any of the operands will become dead as well.
MutableArrayRef<Operand> operands = inst->getAllOperands();
for (Operand &operand : operands) {
SILValue operandVal = operand.get();
if (!operandVal)
continue;
// Remove the reference from the instruction being deleted to this
// operand.
operand.drop();
// If the operand is an instruction that is only used by the instruction
// being deleted, delete it.
if (auto *operandValInst = operandVal->getDefiningInstruction())
if (!deadInsts.count(operandValInst)
&& isInstructionTriviallyDead(operandValInst))
nextInsts.insert(operandValInst);
}
// 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>(inst);
if (fri && fri->getInitiallyReferencedFunction())
fri->dropReferencedFunction();
auto *dfri = dyn_cast<DynamicFunctionRefInst>(inst);
if (dfri && dfri->getInitiallyReferencedFunction())
dfri->dropReferencedFunction();
auto *pfri = dyn_cast<PreviousDynamicFunctionRefInst>(inst);
if (pfri && pfri->getInitiallyReferencedFunction())
pfri->dropReferencedFunction();
}
for (auto inst : deadInsts) {
// This will remove this instruction and all its uses.
eraseFromParentWithDebugInsts(inst, callback);
}
nextInsts.swap(deadInsts);
nextInsts.clear();
}
}
/// If the given instruction is dead, delete it along with its dead
/// operands.
///
/// \param inst 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 *inst,
bool force,
CallbackTy callback) {
ArrayRef<SILInstruction *> ai = ArrayRef<SILInstruction *>(inst);
recursivelyDeleteTriviallyDeadInstructions(ai, force, callback);
}
void swift::eraseUsesOfInstruction(SILInstruction *inst, CallbackTy callback) {
for (auto result : inst->getResults()) {
while (!result->use_empty()) {
auto ui = result->use_begin();
auto *user = ui->getUser();
assert(user && "User should never be NULL!");
// 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 &operand : user->getAllOperands()) {
if (auto *operandI = operand.get()->getDefiningInstruction()) {
// Don't recursively delete the instruction we're working on.
// FIXME: what if we're being recursively invoked?
if (operandI != inst) {
operand.drop();
recursivelyDeleteTriviallyDeadInstructions(operandI, false,
callback);
}
}
}
callback(user);
user->eraseFromParent();
}
}
}
void swift::collectUsesOfValue(SILValue v,
llvm::SmallPtrSetImpl<SILInstruction *> &insts) {
for (auto ui = v->use_begin(), E = v->use_end(); ui != E; ui++) {
auto *user = ui->getUser();
// Instruction has been processed.
if (!insts.insert(user).second)
continue;
// Collect the users of this instruction.
for (auto result : user->getResults())
collectUsesOfValue(result, insts);
}
}
void swift::eraseUsesOfValue(SILValue v) {
llvm::SmallPtrSet<SILInstruction *, 4> insts;
// Collect the uses.
collectUsesOfValue(v, insts);
// Erase the uses, we can have instructions that become dead because
// of the removal of these instructions, leave to DCE to cleanup.
// Its not safe to do recursively delete here as some of the SILInstruction
// maybe tracked by this set.
for (auto inst : insts) {
inst->replaceAllUsesOfAllResultsWithUndef();
inst->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(SILValue v) {
if (auto Apply = FullApplySite::isa(v))
return Apply;
if (isa<UpcastInst>(v) || isa<EnumInst>(v) || isa<UncheckedRefCastInst>(v))
return findApplyFromDevirtualizedResult(
cast<SingleValueInstruction>(v)->getOperand(0));
return FullApplySite();
}
bool swift::mayBindDynamicSelf(SILFunction *F) {
if (!F->hasSelfMetadataParam())
return false;
SILValue mdArg = F->getSelfMetadataArgument();
for (Operand *mdUse : F->getSelfMetadataArgument()->getUses()) {
SILInstruction *mdUser = mdUse->getUser();
for (Operand &typeDepOp : mdUser->getTypeDependentOperands()) {
if (typeDepOp.get() == mdArg)
return true;
}
}
return false;
}
static SILValue skipAddrProjections(SILValue v) {
for (;;) {
switch (v->getKind()) {
case ValueKind::IndexAddrInst:
case ValueKind::IndexRawPointerInst:
case ValueKind::StructElementAddrInst:
case ValueKind::TupleElementAddrInst:
v = cast<SingleValueInstruction>(v)->getOperand(0);
break;
default:
return v;
}
}
llvm_unreachable("there is no escape from an infinite loop");
}
/// Check whether the \p addr is an address of a tail-allocated array element.
bool swift::isAddressOfArrayElement(SILValue addr) {
addr = stripAddressProjections(addr);
if (auto *md = dyn_cast<MarkDependenceInst>(addr))
addr = stripAddressProjections(md->getValue());
// High-level SIL: check for an get_element_address array semantics call.
if (auto *ptrToAddr = dyn_cast<PointerToAddressInst>(addr))
if (auto *sei = dyn_cast<StructExtractInst>(ptrToAddr->getOperand())) {
ArraySemanticsCall call(sei->getOperand());
if (call && call.getKind() == ArrayCallKind::kGetElementAddress)
return true;
}
// Check for an tail-address (of an array buffer object).
if (isa<RefTailAddrInst>(skipAddrProjections(addr)))
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 *domInfo) {
FunctionRefInst *funcRef = cast<FunctionRefInst>(ai->getCallee());
SILBasicBlock *domBB = domInfo->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());
}
/// 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 (auto *cbi = dyn_cast<CondBranchInst>(branch)) {
SmallVector<SILValue, 8> trueArgs;
SmallVector<SILValue, 8> falseArgs;
for (auto arg : cbi->getTrueArgs())
trueArgs.push_back(arg);
for (auto arg : cbi->getFalseArgs())
falseArgs.push_back(arg);
if (dest == cbi->getTrueBB()) {
trueArgs.push_back(val);
assert(trueArgs.size() == dest->getNumArguments());
} else {
falseArgs.push_back(val);
assert(falseArgs.size() == dest->getNumArguments());
}
return builder.createCondBranch(
cbi->getLoc(), cbi->getCondition(), cbi->getTrueBB(), trueArgs,
cbi->getFalseBB(), falseArgs, cbi->getTrueBBCount(),
cbi->getFalseBBCount());
}
if (auto *bi = dyn_cast<BranchInst>(branch)) {
SmallVector<SILValue, 8> args;
for (auto arg : bi->getArgs())
args.push_back(arg);
args.push_back(val);
assert(args.size() == dest->getNumArguments());
return builder.createBranch(bi->getLoc(), bi->getDestBB(), args);
}
llvm_unreachable("unsupported terminator");
}
SILLinkage swift::getSpecializedLinkage(SILFunction *f, SILLinkage linkage) {
if (hasPrivateVisibility(linkage) && !f->isSerialized()) {
// Specializations of private symbols should remain so, unless
// they were serialized, which can only happen when specializing
// definitions from a standard library built with -sil-serialize-all.
return SILLinkage::Private;
}
return SILLinkage::Shared;
}
/// 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.
SILValue swift::castValueToABICompatibleType(SILBuilder *builder,
SILLocation loc, SILValue value,
SILType srcTy, SILType destTy) {
// No cast is required if types are the same.
if (srcTy == destTy)
return value;
assert(srcTy.isAddress() == destTy.isAddress()
&& "Addresses aren't compatible with values");
if (srcTy.isAddress() && destTy.isAddress()) {
// Cast between two addresses and that's it.
return builder->createUncheckedAddrCast(loc, value, destTy);
}
// If both types are classes and dest is the superclass of src,
// simply perform an upcast.
if (destTy.isExactSuperclassOf(srcTy)) {
return builder->createUpcast(loc, value, destTy);
}
if (srcTy.isHeapObjectReferenceType() && destTy.isHeapObjectReferenceType()) {
return builder->createUncheckedRefCast(loc, value, destTy);
}
if (auto mt1 = srcTy.getAs<AnyMetatypeType>()) {
if (auto mt2 = destTy.getAs<AnyMetatypeType>()) {
if (mt1->getRepresentation() == mt2->getRepresentation()) {
// If builder.Type needs to be casted to A.Type and
// A is a superclass of builder, then it can be done by means
// of a simple upcast.
if (mt2.getInstanceType()->isExactSuperclassOf(mt1.getInstanceType())) {
return builder->createUpcast(loc, value, destTy);
}
// Cast between two metatypes and that's it.
return builder->createUncheckedBitCast(loc, value, destTy);
}
}
}
// Check if src and dest types are optional.
auto optionalSrcTy = srcTy.getOptionalObjectType();
auto optionalDestTy = destTy.getOptionalObjectType();
// 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.isExactSuperclassOf(optionalSrcTy)) {
// Insert upcast.
return builder->createUpcast(loc, value, destTy);
}
// Unwrap the original optional value.
auto *someDecl = builder->getASTContext().getOptionalSomeDecl();
auto *noneBB = builder->getFunction().createBasicBlock();
auto *someBB = builder->getFunction().createBasicBlock();
auto *curBB = builder->getInsertionPoint()->getParent();
auto *contBB = curBB->split(builder->getInsertionPoint());
contBB->createPhiArgument(destTy, ValueOwnershipKind::Owned);
SmallVector<std::pair<EnumElementDecl *, SILBasicBlock *>, 1> caseBBs;
caseBBs.push_back(std::make_pair(someDecl, someBB));
builder->setInsertionPoint(curBB);
builder->createSwitchEnum(loc, value, noneBB, caseBBs);
// Handle the Some case.
builder->setInsertionPoint(someBB);
SILValue unwrappedValue =
builder->createUncheckedEnumData(loc, value, someDecl);
// Cast the unwrapped value.
auto castedUnwrappedValue = castValueToABICompatibleType(
builder, loc, unwrappedValue, optionalSrcTy, optionalDestTy);
// Wrap into optional.
auto castedValue =
builder->createOptionalSome(loc, castedUnwrappedValue, destTy);
builder->createBranch(loc, contBB, {castedValue});
// Handle the None case.
builder->setInsertionPoint(noneBB);
castedValue = builder->createOptionalNone(loc, destTy);
builder->createBranch(loc, contBB, {castedValue});
builder->setInsertionPoint(contBB->begin());
return contBB->getArgument(0);
}
// Src is not optional, but dest is optional.
if (!optionalSrcTy && optionalDestTy) {
auto optionalSrcCanTy =
OptionalType::get(srcTy.getASTType())->getCanonicalType();
auto loweredOptionalSrcType =
SILType::getPrimitiveObjectType(optionalSrcCanTy);
// Wrap the source value into an optional first.
SILValue wrappedValue =
builder->createOptionalSome(loc, value, loweredOptionalSrcType);
// Cast the wrapped value.
return castValueToABICompatibleType(builder, loc, wrappedValue,
wrappedValue->getType(), destTy);
}
// Handle tuple types.
// Extract elements, cast each of them, create a new tuple.
if (auto srcTupleTy = srcTy.getAs<TupleType>()) {
SmallVector<SILValue, 8> expectedTuple;
for (unsigned i = 0, e = srcTupleTy->getNumElements(); i < e; i++) {
SILValue element = builder->createTupleExtract(loc, value, i);
// Cast the value if necessary.
element = castValueToABICompatibleType(builder, loc, element,
srcTy.getTupleElementType(i),
destTy.getTupleElementType(i));
expectedTuple.push_back(element);
}
return builder->createTuple(loc, destTy, expectedTuple);
}
// Function types are interchangeable if they're also ABI-compatible.
if (srcTy.is<SILFunctionType>()) {
if (destTy.is<SILFunctionType>()) {
assert(srcTy.getAs<SILFunctionType>()->isNoEscape()
== destTy.getAs<SILFunctionType>()->isNoEscape()
|| srcTy.getAs<SILFunctionType>()->getRepresentation()
!= SILFunctionType::Representation::Thick
&& "Swift thick functions that differ in escapeness are "
"not ABI "
"compatible");
// Insert convert_function.
return builder->createConvertFunction(loc, value, destTy,
/*WithoutActuallyEscaping=*/false);
}
}
llvm::errs() << "Source type: " << srcTy << "\n";
llvm::errs() << "Destination type: " << destTy << "\n";
llvm_unreachable("Unknown combination of types for casting");
}
ProjectBoxInst *swift::getOrCreateProjectBox(AllocBoxInst *abi,
unsigned index) {
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 && pbi->getFieldIndex() == index)
return pbi;
}
SILBuilder builder(nextInst);
return builder.createProjectBox(abi->getLoc(), abi, index);
}
// Peek through trivial Enum initialization, typically for pointless
// Optionals.
//
// Given an UncheckedTakeEnumDataAddrInst, check that there are no
// other uses of the Enum value and return the address used to initialized the
// enum's payload:
//
// %stack_adr = alloc_stack
// %data_adr = init_enum_data_addr %stk_adr
// %enum_adr = inject_enum_addr %stack_adr
// %copy_src = unchecked_take_enum_data_addr %enum_adr
// dealloc_stack %stack_adr
// (No other uses of %stack_adr.)
InitEnumDataAddrInst *
swift::findInitAddressForTrivialEnum(UncheckedTakeEnumDataAddrInst *utedai) {
auto *asi = dyn_cast<AllocStackInst>(utedai->getOperand());
if (!asi)
return nullptr;
SILInstruction *singleUser = nullptr;
for (auto use : asi->getUses()) {
auto *user = use->getUser();
if (user == utedai)
continue;
// As long as there's only one UncheckedTakeEnumDataAddrInst and one
// InitEnumDataAddrInst, we don't care how many InjectEnumAddr and
// DeallocStack users there are.
if (isa<InjectEnumAddrInst>(user) || isa<DeallocStackInst>(user))
continue;
if (singleUser)
return nullptr;
singleUser = user;
}
if (!singleUser)
return nullptr;
// Assume, without checking, that the returned InitEnumDataAddr dominates the
// given UncheckedTakeEnumDataAddrInst, because that's how SIL is defined. I
// don't know where this is actually verified.
return dyn_cast<InitEnumDataAddrInst>(singleUser);
}
//===----------------------------------------------------------------------===//
// 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.
SingleValueInstruction *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->getReferencedFunctionOrNull();
if (!Fn)
return false;
if (ai->getNumArguments() != 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->getReferencedFunctionOrNull();
auto *friRightFun = friRight->getReferencedFunctionOrNull();
if (friLeftFun->getEffectsKind() >= EffectsKind::ReleaseNone
|| friRightFun->getEffectsKind() >= EffectsKind::ReleaseNone)
return false;
if (!friLeftFun->hasSemanticsAttrs() || !friRightFun->hasSemanticsAttrs())
return false;
auto aiLeftOperandsNum = aiLeft->getNumOperands();
auto aiRightOperandsNum = aiRight->getNumOperands();
// makeUTF8 should have following parameters:
// (start: RawPointer, utf8CodeUnitCount: Word, isASCII: Int1)
if (!((friLeftFun->hasSemanticsAttr("string.makeUTF8")
&& aiLeftOperandsNum == 5)
|| (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;
}
SingleValueInstruction *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 ascii = isAscii();
auto ilType = aiLeft->getOperand(3)->getType();
auto *asciiLiteral =
builder.createIntegerLiteral(ai->getLoc(), ilType, intmax_t(ascii));
arguments.push_back(asciiLiteral);
}
// Type.
arguments.push_back(funcResultType);
return builder.createApply(ai->getLoc(), friConvertFromBuiltin,
SubstitutionMap(), arguments);
}
/// Top level entry point
SingleValueInstruction *swift::tryToConcatenateStrings(ApplyInst *ai,
SILBuilder &builder) {
return StringConcatenationOptimizer(ai, builder).optimize();
}
//===----------------------------------------------------------------------===//
// Closure Deletion
//===----------------------------------------------------------------------===//
/// NOTE: Instructions with transitive ownership kind are assumed to not keep
/// the underlying closure alive as well. This is meant for instructions only
/// with non-transitive users.
static bool useDoesNotKeepClosureAlive(const SILInstruction *inst) {
switch (inst->getKind()) {
case SILInstructionKind::StrongRetainInst:
case SILInstructionKind::StrongReleaseInst:
case SILInstructionKind::DestroyValueInst:
case SILInstructionKind::RetainValueInst:
case SILInstructionKind::ReleaseValueInst:
case SILInstructionKind::DebugValueInst:
case SILInstructionKind::EndBorrowInst:
return true;
default:
return false;
}
}
static bool useHasTransitiveOwnership(const SILInstruction *inst) {
// convert_escape_to_noescape is used to convert to a @noescape function type.
// It does not change ownership of the function value.
if (isa<ConvertEscapeToNoEscapeInst>(inst))
return true;
// Look through copy_value, begin_borrow. They are inert for our purposes, but
// we need to look through it.
return isa<CopyValueInst>(inst) || isa<BeginBorrowInst>(inst);
}
static SILValue createLifetimeExtendedAllocStack(
SILBuilder &builder, SILLocation loc, SILValue arg,
ArrayRef<SILBasicBlock *> exitingBlocks, InstModCallbacks callbacks) {
AllocStackInst *asi = nullptr;
{
// Save our insert point and create a new alloc_stack in the initial BB and
// dealloc_stack in all exit blocks.
auto *oldInsertPt = &*builder.getInsertionPoint();
builder.setInsertionPoint(builder.getFunction().begin()->begin());
asi = builder.createAllocStack(loc, arg->getType());
callbacks.createdNewInst(asi);
for (auto *BB : exitingBlocks) {
builder.setInsertionPoint(BB->getTerminator());
callbacks.createdNewInst(builder.createDeallocStack(loc, asi));
}
builder.setInsertionPoint(oldInsertPt);
}
assert(asi != nullptr);
// Then perform a copy_addr [take] [init] right after the partial_apply from
// the original address argument to the new alloc_stack that we have
// created.
callbacks.createdNewInst(
builder.createCopyAddr(loc, arg, asi, IsTake, IsInitialization));
// Return the new alloc_stack inst that has the appropriate live range to
// destroy said values.
return asi;
}
static bool shouldDestroyPartialApplyCapturedArg(SILValue arg,
SILParameterInfo paramInfo,
const SILFunction &F) {
// 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 (paramInfo.isIndirectMutating())
return false;
// If we have a trivial type, we do not need to put in any extra releases.
if (arg->getType().isTrivial(F))
return false;
// We handle all other cases.
return true;
}
// *HEY YOU, YES YOU, PLEASE READ*. Even though a textual partial apply is
// printed with the convention of the closed over function upon it, all
// non-inout arguments to a partial_apply are passed at +1. This includes
// arguments that will eventually be passed as guaranteed or in_guaranteed to
// the closed over function. This is because the partial apply is building up a
// boxed aggregate to send off to the closed over function. Of course when you
// call the function, the proper conventions will be used.
void swift::releasePartialApplyCapturedArg(SILBuilder &builder, SILLocation loc,
SILValue arg,
SILParameterInfo paramInfo,
InstModCallbacks callbacks) {
if (!shouldDestroyPartialApplyCapturedArg(arg, paramInfo,
builder.getFunction()))
return;
// Otherwise, we need to destroy the argument. If we have an address, we
// insert a destroy_addr and return. Any live range issues must have been
// dealt with by our caller.
if (arg->getType().isAddress()) {
// Then emit the destroy_addr for this arg
SILInstruction *newInst = builder.emitDestroyAddrAndFold(loc, arg);
callbacks.createdNewInst(newInst);
return;
}
// Otherwise, we have an object. We emit the most optimized form of release
// possible for that value.
// If we have qualified ownership, we should just emit a destroy value.
if (arg->getFunction()->hasOwnership()) {
callbacks.createdNewInst(builder.createDestroyValue(loc, arg));
return;
}
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 *>());
}
/// 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 bool releaseCapturedArgsOfDeadPartialApply(PartialApplyInst *pai,
ReleaseTracker &tracker,
InstModCallbacks callbacks) {
SILBuilderWithScope builder(pai);
SILLocation loc = pai->getLoc();
CanSILFunctionType paiTy =
pai->getCallee()->getType().getAs<SILFunctionType>();
ArrayRef<SILParameterInfo> params = paiTy->getParameters();
llvm::SmallVector<SILValue, 8> args;
for (SILValue v : pai->getArguments()) {
// If any of our arguments contain open existentials, bail. We do not
// support this for now so that we can avoid having to re-order stack
// locations (a larger change).
if (v->getType().hasOpenedExistential())
return false;
args.emplace_back(v);
}
unsigned delta = params.size() - args.size();
assert(delta <= params.size()
&& "Error, more args to partial apply than "
"params in its interface.");
params = params.drop_front(delta);
llvm::SmallVector<SILBasicBlock *, 2> exitingBlocks;
pai->getFunction()->findExitingBlocks(exitingBlocks);
// Go through our argument list and create new alloc_stacks for each
// non-trivial address value. This ensures that the memory location that we
// are cleaning up has the same live range as the partial_apply. Otherwise, we
// may be inserting destroy_addr of alloc_stack that have already been passed
// to a dealloc_stack.
for (unsigned i : llvm::reverse(indices(args))) {
SILValue arg = args[i];
SILParameterInfo paramInfo = params[i];
// If we are not going to destroy this partial_apply, continue.
if (!shouldDestroyPartialApplyCapturedArg(arg, paramInfo,
builder.getFunction()))
continue;
// If we have an object, we will not have live range issues, just continue.
if (arg->getType().isObject())
continue;
// Now that we know that we have a non-argument address, perform a take-init
// of arg into a lifetime extended alloc_stack
args[i] = createLifetimeExtendedAllocStack(builder, loc, arg, exitingBlocks,
callbacks);
}
// Emit a destroy for each captured closure argument at each final release
// point.
for (auto *finalRelease : tracker.getFinalReleases()) {
builder.setInsertionPoint(finalRelease);
builder.setCurrentDebugScope(finalRelease->getDebugScope());
for (unsigned i : indices(args)) {
SILValue arg = args[i];
SILParameterInfo param = params[i];
releasePartialApplyCapturedArg(builder, loc, arg, param, callbacks);
}
}
return true;
}
static bool
deadMarkDependenceUser(SILInstruction *inst,
SmallVectorImpl<SILInstruction *> &deleteInsts) {
if (!isa<MarkDependenceInst>(inst))
return false;
deleteInsts.push_back(inst);
for (auto *use : cast<SingleValueInstruction>(inst)->getUses()) {
if (!deadMarkDependenceUser(use->getUser(), deleteInsts))
return false;
}
return true;
}
/// TODO: Generalize this to general objects.
bool swift::tryDeleteDeadClosure(SingleValueInstruction *closure,
InstModCallbacks callbacks) {
auto *pa = dyn_cast<PartialApplyInst>(closure);
// We currently only handle locally identified values that do not escape. We
// also assume that the partial apply does not capture any addresses.
if (!pa && !isa<ThinToThickFunctionInst>(closure))
return false;
// A stack allocated partial apply does not have any release users. Delete it
// if the only users are the dealloc_stack and mark_dependence instructions.
if (pa && pa->isOnStack()) {
SmallVector<SILInstruction *, 8> deleteInsts;
for (auto *use : pa->getUses()) {
if (isa<DeallocStackInst>(use->getUser())
|| isa<DebugValueInst>(use->getUser()))
deleteInsts.push_back(use->getUser());
else if (!deadMarkDependenceUser(use->getUser(), deleteInsts))
return false;
}
for (auto *inst : reverse(deleteInsts))
callbacks.deleteInst(inst);
callbacks.deleteInst(pa);
// Note: the lifetime of the captured arguments is managed outside of the
// trivial closure value i.e: there will already be releases for the
// captured arguments. Releasing captured arguments is not necessary.
return true;
}
// 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(useDoesNotKeepClosureAlive, useHasTransitiveOwnership);
// 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)) {
// If we can not decrement the ref counts of the dead partial apply for any
// reason, bail.
if (!releaseCapturedArgsOfDeadPartialApply(pai, tracker, callbacks))
return false;
}
// Then delete all user instructions in reverse so that leaf uses are deleted
// first.
for (auto *user : reverse(tracker.getTrackedUsers())) {
assert(user->getResults().empty()
|| useHasTransitiveOwnership(user)
&& "We expect only ARC operations without "
"results or a cast from escape to noescape without users");
callbacks.deleteInst(user);
}
// Finally delete the closure.
callbacks.deleteInst(closure);
return true;
}
bool swift::simplifyUsers(SingleValueInstruction *inst) {
bool changed = false;
for (auto ui = inst->use_begin(), ue = inst->use_end(); ui != ue;) {
SILInstruction *user = ui->getUser();
++ui;
auto svi = dyn_cast<SingleValueInstruction>(user);
if (!svi)
continue;
SILValue S = simplifyInstruction(svi);
if (!S)
continue;
replaceAllSimplifiedUsesAndErase(svi, S);
changed = true;
}
return changed;
}
/// True if a type can be expanded without a significant increase to code size.
bool swift::shouldExpand(SILModule &module, SILType ty) {
// FIXME: Expansion
auto expansion = ResilienceExpansion::Minimal;
if (module.Types.getTypeLowering(ty, expansion).isAddressOnly()) {
return false;
}
if (EnableExpandAll) {
return true;
}
unsigned numFields = module.Types.countNumberOfFields(ty, expansion);
return (numFields <= 6);
}
/// Some support functions for the global-opt and let-properties-opts
// Encapsulate the state used for recursive analysis of a static
// initializer. Discover all the instruction in a use-def graph and return them
// in topological order.
//
// TODO: We should have a DFS utility for this sort of thing so it isn't
// recursive.
class StaticInitializerAnalysis {
SmallVectorImpl<SILInstruction *> &postOrderInstructions;
llvm::SmallDenseSet<SILValue, 8> visited;
int recursionLevel = 0;
public:
StaticInitializerAnalysis(
SmallVectorImpl<SILInstruction *> &postOrderInstructions)
: postOrderInstructions(postOrderInstructions) {}
// Perform a recursive DFS on on the use-def graph rooted at `V`. Insert
// values in the `visited` set in preorder. Insert values in
// `postOrderInstructions` in postorder so that the instructions are
// topologically def-use ordered (in execution order).
bool analyze(SILValue rootValue) {
return recursivelyAnalyzeOperand(rootValue);
}
protected:
bool recursivelyAnalyzeOperand(SILValue v) {
if (!visited.insert(v).second)
return true;
if (++recursionLevel > 50)
return false;
// TODO: For multi-result instructions, we could simply insert all result
// values in the visited set here.
auto *inst = dyn_cast<SingleValueInstruction>(v);
if (!inst)
return false;
if (!recursivelyAnalyzeInstruction(inst))
return false;
postOrderInstructions.push_back(inst);
--recursionLevel;
return true;
}
bool recursivelyAnalyzeInstruction(SILInstruction *inst) {
if (auto *si = dyn_cast<StructInst>(inst)) {
// If it is not a struct which is a simple type, bail.
if (!si->getType().isTrivial(*si->getFunction()))
return false;
return llvm::all_of(si->getAllOperands(), [&](Operand &operand) -> bool {
return recursivelyAnalyzeOperand(operand.get());
});
}
if (auto *ti = dyn_cast<TupleInst>(inst)) {
// If it is not a tuple which is a simple type, bail.
if (!ti->getType().isTrivial(*ti->getFunction()))
return false;
return llvm::all_of(ti->getAllOperands(), [&](Operand &operand) -> bool {
return recursivelyAnalyzeOperand(operand.get());
});
}
if (auto *bi = dyn_cast<BuiltinInst>(inst)) {
switch (bi->getBuiltinInfo().ID) {
case BuiltinValueKind::FPTrunc:
if (auto *li = dyn_cast<LiteralInst>(bi->getArguments()[0])) {
return recursivelyAnalyzeOperand(li);
}
return false;
default:
return false;
}
}
return isa<IntegerLiteralInst>(inst) || isa<FloatLiteralInst>(inst)
|| isa<StringLiteralInst>(inst);
}
};
/// Check if the value of v is computed by means of a simple initialization.
/// Populate `forwardInstructions` with references to all the instructions
/// that participate in the use-def graph required to compute `V`. The
/// instructions will be in def-use topological order.
bool swift::analyzeStaticInitializer(
SILValue v, SmallVectorImpl<SILInstruction *> &forwardInstructions) {
return StaticInitializerAnalysis(forwardInstructions).analyze(v);
}
/// FIXME: This must be kept in sync with replaceLoadSequence()
/// below. What a horrible design.
bool swift::canReplaceLoadSequence(SILInstruction *inst) {
if (auto *cai = dyn_cast<CopyAddrInst>(inst))
return true;
if (auto *li = dyn_cast<LoadInst>(inst))
return true;
if (auto *seai = dyn_cast<StructElementAddrInst>(inst)) {
for (auto seaiUse : seai->getUses()) {
if (!canReplaceLoadSequence(seaiUse->getUser()))
return false;
}
return true;
}
if (auto *teai = dyn_cast<TupleElementAddrInst>(inst)) {
for (auto teaiUse : teai->getUses()) {
if (!canReplaceLoadSequence(teaiUse->getUser()))
return false;
}
return true;
}
if (auto *ba = dyn_cast<BeginAccessInst>(inst)) {
for (auto use : ba->getUses()) {
if (!canReplaceLoadSequence(use->getUser()))
return false;
}
return true;
}
// Incidental uses of an address are meaningless with regard to the loaded
// value.
if (isIncidentalUse(inst) || isa<BeginUnpairedAccessInst>(inst))
return true;
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.
///
/// FIXME: this utility does not make sense as an API. How can the caller
/// guarantee that the only uses of `I` are struct_element_addr and
/// tuple_element_addr?
void swift::replaceLoadSequence(SILInstruction *inst, SILValue value) {
if (auto *cai = dyn_cast<CopyAddrInst>(inst)) {
SILBuilder builder(cai);
builder.createStore(cai->getLoc(), value, cai->getDest(),
StoreOwnershipQualifier::Unqualified);
return;
}
if (auto *li = dyn_cast<LoadInst>(inst)) {
li->replaceAllUsesWith(value);
return;
}
if (auto *seai = dyn_cast<StructElementAddrInst>(inst)) {
SILBuilder builder(seai);
auto *sei =
builder.createStructExtract(seai->getLoc(), value, seai->getField());
for (auto seaiUse : seai->getUses()) {
replaceLoadSequence(seaiUse->getUser(), sei);
}
return;
}
if (auto *teai = dyn_cast<TupleElementAddrInst>(inst)) {
SILBuilder builder(teai);
auto *tei =
builder.createTupleExtract(teai->getLoc(), value, teai->getFieldNo());
for (auto teaiUse : teai->getUses()) {
replaceLoadSequence(teaiUse->getUser(), tei);
}
return;
}
if (auto *ba = dyn_cast<BeginAccessInst>(inst)) {
for (auto use : ba->getUses()) {
replaceLoadSequence(use->getUser(), value);
}
return;
}
// Incidental uses of an addres are meaningless with regard to the loaded
// value.
if (isIncidentalUse(inst) || isa<BeginUnpairedAccessInst>(inst))
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 &module, SILDeclRef decl) {
if (decl.isForeign)
return false;
const DeclContext *assocDC = module.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->hasAccess())
return false;
// Only consider 'private' members, unless we are in whole-module compilation.
switch (afd->getEffectiveAccess()) {
case AccessLevel::Open:
return false;
case AccessLevel::Public:
if (isa<ConstructorDecl>(afd)) {
// Constructors are special: a derived class in another module can
// "override" a constructor if its class is "open", although the
// constructor itself is not open.
auto *nd = afd->getDeclContext()->getSelfNominalTypeDecl();
if (nd->getEffectiveAccess() == AccessLevel::Open)
return false;
}
LLVM_FALLTHROUGH;
case AccessLevel::Internal:
return module.isWholeModule();
case AccessLevel::FilePrivate:
case AccessLevel::Private:
return true;
}
llvm_unreachable("Unhandled access level in switch.");
}
Optional<FindLocalApplySitesResult>
swift::findLocalApplySites(FunctionRefBaseInst *fri) {
SmallVector<Operand *, 32> worklist(fri->use_begin(), fri->use_end());
Optional<FindLocalApplySitesResult> f;
f.emplace();
// Optimistically state that we have no escapes before our def-use dataflow.
f->escapes = false;
while (!worklist.empty()) {
auto *op = worklist.pop_back_val();
auto *user = op->getUser();
// If we have a full apply site as our user.
if (auto apply = FullApplySite::isa(user)) {
if (apply.getCallee() == op->get()) {
f->fullApplySites.push_back(apply);
continue;
}
}
// If we have a partial apply as a user, start tracking it, but also look at
// its users.
if (auto *pai = dyn_cast<PartialApplyInst>(user)) {
if (pai->getCallee() == op->get()) {
// Track the partial apply that we saw so we can potentially eliminate
// dead closure arguments.
f->partialApplySites.push_back(pai);
// Look to see if we can find a full application of this partial apply
// as well.
llvm::copy(pai->getUses(), std::back_inserter(worklist));
continue;
}
}
// Otherwise, see if we have any function casts to look through...
switch (user->getKind()) {
case SILInstructionKind::ThinToThickFunctionInst:
case SILInstructionKind::ConvertFunctionInst:
case SILInstructionKind::ConvertEscapeToNoEscapeInst:
llvm::copy(cast<SingleValueInstruction>(user)->getUses(),
std::back_inserter(worklist));
continue;
// A partial_apply [stack] marks its captured arguments with
// mark_dependence.
case SILInstructionKind::MarkDependenceInst:
llvm::copy(cast<SingleValueInstruction>(user)->getUses(),
std::back_inserter(worklist));
continue;
// Look through any reference count instructions since these are not
// escapes:
case SILInstructionKind::CopyValueInst:
llvm::copy(cast<CopyValueInst>(user)->getUses(),
std::back_inserter(worklist));
continue;
case SILInstructionKind::StrongRetainInst:
case SILInstructionKind::StrongReleaseInst:
case SILInstructionKind::RetainValueInst:
case SILInstructionKind::ReleaseValueInst:
case SILInstructionKind::DestroyValueInst:
// A partial_apply [stack] is deallocated with a dealloc_stack.
case SILInstructionKind::DeallocStackInst:
continue;
default:
break;
}
// But everything else is considered an escape.
f->escapes = true;
}
// If we did escape and didn't find any apply sites, then we have no
// information for our users that is interesting.
if (f->escapes && f->partialApplySites.empty() && f->fullApplySites.empty())
return None;
return f;
}
/// Insert destroys of captured arguments of partial_apply [stack].
void swift::insertDestroyOfCapturedArguments(
PartialApplyInst *pai, SILBuilder &builder,
llvm::function_ref<bool(SILValue)> shouldInsertDestroy) {
assert(pai->isOnStack());
ApplySite site(pai);
SILFunctionConventions calleeConv(site.getSubstCalleeType(),
pai->getModule());
auto loc = RegularLocation::getAutoGeneratedLocation();
for (auto &arg : pai->getArgumentOperands()) {
if (!shouldInsertDestroy(arg.get()))
continue;
unsigned calleeArgumentIndex = site.getCalleeArgIndex(arg);
assert(calleeArgumentIndex >= calleeConv.getSILArgIndexOfFirstParam());
auto paramInfo = calleeConv.getParamInfoForSILArg(calleeArgumentIndex);
releasePartialApplyCapturedArg(builder, loc, arg.get(), paramInfo);
}
}