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//===--- GenericSpecializer.cpp - Specialization of generic functions -----===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 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
//
//===----------------------------------------------------------------------===//
//
// Specialize calls to generic functions by substituting static type
// information.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "sil-generic-specializer"
#include "swift/SIL/OptimizationRemark.h"
#include "swift/SIL/SILFunction.h"
#include "swift/SIL/SILInstruction.h"
#include "swift/SILOptimizer/PassManager/Transforms.h"
#include "swift/SILOptimizer/Utils/BasicBlockOptUtils.h"
#include "swift/SILOptimizer/Utils/ConstantFolding.h"
#include "swift/SILOptimizer/Utils/Devirtualize.h"
#include "swift/SILOptimizer/Utils/Generics.h"
#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
#include "swift/SILOptimizer/Utils/SILOptFunctionBuilder.h"
#include "swift/SILOptimizer/Utils/SILInliner.h"
#include "swift/SILOptimizer/Utils/StackNesting.h"
#include "llvm/ADT/SmallVector.h"
using namespace swift;
namespace {
static void transferSpecializeAttributeTargets(SILModule &M,
SILOptFunctionBuilder &builder,
Decl *d) {
auto *vd = cast<AbstractFunctionDecl>(d);
for (auto *A : vd->getAttrs().getAttributes<SpecializeAttr>()) {
auto *SA = cast<SpecializeAttr>(A);
// Filter _spi.
auto spiGroups = SA->getSPIGroups();
auto hasSPIGroup = !spiGroups.empty();
if (hasSPIGroup) {
if (vd->getModuleContext() != M.getSwiftModule() &&
!M.getSwiftModule()->isImportedAsSPI(SA, vd)) {
continue;
}
}
if (auto *targetFunctionDecl = SA->getTargetFunctionDecl(vd)) {
auto target = SILDeclRef(targetFunctionDecl);
auto targetSILFunction = builder.getOrCreateFunction(
SILLocation(vd), target, NotForDefinition,
[&builder](SILLocation loc, SILDeclRef constant) -> SILFunction * {
return builder.getOrCreateFunction(loc, constant, NotForDefinition);
});
auto kind = SA->getSpecializationKind() ==
SpecializeAttr::SpecializationKind::Full
? SILSpecializeAttr::SpecializationKind::Full
: SILSpecializeAttr::SpecializationKind::Partial;
Identifier spiGroupIdent;
if (hasSPIGroup) {
spiGroupIdent = spiGroups[0];
}
auto availability = AvailabilityInference::annotatedAvailableRangeForAttr(
SA, M.getSwiftModule()->getASTContext());
targetSILFunction->addSpecializeAttr(SILSpecializeAttr::create(
M, SA->getSpecializedSignature(vd), SA->getTypeErasedParams(),
SA->isExported(), kind, nullptr,
spiGroupIdent, vd->getModuleContext(), availability));
}
}
}
} // end anonymous namespace
bool swift::specializeAppliesInFunction(SILFunction &F,
SILTransform *transform,
bool isMandatory) {
SILOptFunctionBuilder FunctionBuilder(*transform);
DeadInstructionSet DeadApplies;
llvm::SmallSetVector<SILInstruction *, 8> Applies;
OptRemark::Emitter ORE(DEBUG_TYPE, F);
bool Changed = false;
for (auto &BB : F) {
// Collect the applies for this block in reverse order so that we
// can pop them off the end of our vector and process them in
// forward order.
for (auto &I : llvm::reverse(BB)) {
// Skip non-apply instructions, apply instructions with no
// substitutions, apply instructions where we do not statically
// know the called function, and apply instructions where we do
// not have the body of the called function.
ApplySite Apply = ApplySite::isa(&I);
if (!Apply || !Apply.hasSubstitutions())
continue;
auto *Callee = Apply.getReferencedFunctionOrNull();
if (!Callee)
continue;
FunctionBuilder.getModule().performOnceForPrespecializedImportedExtensions(
[&FunctionBuilder](AbstractFunctionDecl *pre) {
transferSpecializeAttributeTargets(FunctionBuilder.getModule(), FunctionBuilder,
pre);
});
if (!Callee->isDefinition() && !Callee->hasPrespecialization()) {
ORE.emit([&]() {
using namespace OptRemark;
return RemarkMissed("NoDef", I)
<< "Unable to specialize generic function "
<< NV("Callee", Callee) << " since definition is not visible";
});
continue;
}
Applies.insert(Apply.getInstruction());
}
// Attempt to specialize each apply we collected, deleting any
// that we do specialize (along with other instructions we clone
// in the process of doing so). We pop from the end of the list to
// avoid tricky iterator invalidation issues.
while (!Applies.empty()) {
auto *I = Applies.pop_back_val();
auto Apply = ApplySite::isa(I);
assert(Apply && "Expected an apply!");
SILFunction *Callee = Apply.getReferencedFunctionOrNull();
assert(Callee && "Expected to have a known callee");
if (!Apply.canOptimize())
continue;
if (!isMandatory && !Callee->shouldOptimize())
continue;
// We have a call that can potentially be specialized, so
// attempt to do so.
llvm::SmallVector<SILFunction *, 2> NewFunctions;
trySpecializeApplyOfGeneric(FunctionBuilder, Apply, DeadApplies,
NewFunctions, ORE, isMandatory);
// Remove all the now-dead applies. We must do this immediately
// rather than defer it in order to avoid problems with cloning
// dead instructions when doing recursive specialization.
while (!DeadApplies.empty()) {
auto *AI = DeadApplies.pop_back_val();
// Remove any applies we are deleting so that we don't attempt
// to specialize them.
Applies.remove(AI);
recursivelyDeleteTriviallyDeadInstructions(AI, true);
Changed = true;
}
if (auto *sft = dyn_cast<SILFunctionTransform>(transform)) {
// If calling the specialization utility resulted in new functions
// (as opposed to returning a previous specialization), we need to notify
// the pass manager so that the new functions get optimized.
for (SILFunction *NewF : reverse(NewFunctions)) {
sft->addFunctionToPassManagerWorklist(NewF, Callee);
}
}
}
}
return Changed;
}
namespace {
/// The generic specializer, used in the optimization pipeline.
class GenericSpecializer : public SILFunctionTransform {
/// The entry point to the transformation.
void run() override {
SILFunction &F = *getFunction();
LLVM_DEBUG(llvm::dbgs() << "***** GenericSpecializer on function:"
<< F.getName() << " *****\n");
if (specializeAppliesInFunction(F, this, /*isMandatory*/ false)) {
invalidateAnalysis(SILAnalysis::InvalidationKind::FunctionBody);
}
}
};
} // end anonymous namespace
SILTransform *swift::createGenericSpecializer() {
return new GenericSpecializer();
}
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