Files
swift-mirror/lib/SILPasses/GenericSpecializer.cpp
Adrian Prantl b1a7a7af1b Reference-count inlined functions to keep them alive until we emit debug
info for them and generally clean up the inline scope handling a bit.
Fix the debug scope handling for all clients of SILCloner, especially
the SIL-level spezializers and inliners.
This also adds a ton of additional assertions that will ensure that
future optimization passes won't mess with the debug info in a way that
could confuse the LLVM backend.

Swift SVN r18984
2014-06-18 22:34:10 +00:00

391 lines
13 KiB
C++

//===-- Specializer.cpp ------ Performs Generic Specialization ------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 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
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "specialization"
#include "swift/SIL/SILDebugScope.h"
#include "swift/SIL/SILFunction.h"
#include "swift/SIL/SILInstruction.h"
#include "swift/SIL/SILModule.h"
#include "swift/SIL/TypeSubstCloner.h"
#include "swift/SILPasses/Passes.h"
#include "swift/SILPasses/Utils/Local.h"
#include "swift/SILPasses/Transforms.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/Mangle.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/Debug.h"
using namespace swift;
STATISTIC(NumSpecialized, "Number of functions specialized");
/// Check if we can clone and remap types this function.
static bool canSpecializeFunction(SILFunction *F) {
return !F->isExternalDeclaration();
}
namespace {
class SpecializingCloner : public TypeSubstCloner<SpecializingCloner> {
public:
SpecializingCloner(SILFunction *F,
TypeSubstitutionMap &InterfaceSubs,
TypeSubstitutionMap &ContextSubs,
StringRef NewName,
ArrayRef<Substitution> ApplySubs)
: TypeSubstCloner(*initCloned(F, InterfaceSubs, NewName), *F, ContextSubs,
ApplySubs) {}
/// Clone and remap the types in \p F according to the substitution
/// list in \p Subs.
static SILFunction *cloneFunction(SILFunction *F,
TypeSubstitutionMap &InterfaceSubs,
TypeSubstitutionMap &ContextSubs,
StringRef NewName, ApplyInst *Caller) {
// Clone and specialize the function.
SpecializingCloner SC(F, InterfaceSubs, ContextSubs, NewName,
Caller->getSubstitutions());
SC.populateCloned();
return SC.getCloned();
}
private:
static SILFunction *initCloned(SILFunction *Orig,
TypeSubstitutionMap &InterfaceSubs,
StringRef NewName);
/// Clone the body of the function into the empty function that was created
/// by initCloned.
void populateCloned();
SILFunction *getCloned() { return &getBuilder().getFunction(); }
};
/// Create a new empty function with the correct arguments and a unique name.
SILFunction *SpecializingCloner::initCloned(SILFunction *Orig,
TypeSubstitutionMap &InterfaceSubs,
StringRef NewName) {
SILModule &M = Orig->getModule();
Module *SM = M.getSwiftModule();
CanSILFunctionType FTy =
SILType::substFuncType(M, SM, InterfaceSubs,
Orig->getLoweredFunctionType(),
/*dropGenerics = */ true);
assert((Orig->isTransparent() || Orig->isBare() || Orig->getLocation())
&& "SILFunction missing location");
assert((Orig->isTransparent() || Orig->isBare() || Orig->getDebugScope())
&& "SILFunction missing DebugScope");
assert(!Orig->isGlobalInit() && "Global initializer cannot be cloned");
// Create a new empty function.
SILFunction *NewF =
SILFunction::create(M, getSpecializedLinkage(Orig->getLinkage()),
NewName, FTy, nullptr,
Orig->getLocation(), Orig->isBare(),
Orig->isTransparent(), 0,
Orig->getDebugScope(), Orig->getDeclContext());
NumSpecialized++;
return NewF;
}
void SpecializingCloner::populateCloned() {
SILFunction *Cloned = getCloned();
SILModule &M = Cloned->getModule();
// Create arguments for the entry block.
SILBasicBlock *OrigEntryBB = Original.begin();
SILBasicBlock *ClonedEntryBB = new (M) SILBasicBlock(Cloned);
// Create the entry basic block with the function arguments.
auto I = OrigEntryBB->bbarg_begin(), E = OrigEntryBB->bbarg_end();
while (I != E) {
SILValue MappedValue =
new (M) SILArgument(remapType((*I)->getType()), ClonedEntryBB,
(*I)->getDecl());
ValueMap.insert(std::make_pair(*I, MappedValue));
++I;
}
getBuilder().setInsertionPoint(ClonedEntryBB);
BBMap.insert(std::make_pair(OrigEntryBB, ClonedEntryBB));
// Recursively visit original BBs in depth-first preorder, starting with the
// entry block, cloning all instructions other than terminators.
visitSILBasicBlock(OrigEntryBB);
// Now iterate over the BBs and fix up the terminators.
for (auto BI = BBMap.begin(), BE = BBMap.end(); BI != BE; ++BI) {
getBuilder().setInsertionPoint(BI->second);
visit(BI->first->getTerminator());
}
}
struct GenericSpecializer {
/// A list of ApplyInst instructions.
typedef SmallVector<ApplyInst *, 16> AIList;
/// The SIL Module.
SILModule *M;
/// Maps a function to all of the ApplyInst that call it.
llvm::MapVector<SILFunction *, AIList> ApplyInstMap;
/// A worklist of functions to specialize.
std::vector<SILFunction*> Worklist;
GenericSpecializer(SILModule *Mod) : M(Mod) {}
bool specializeApplyInstGroup(SILFunction *F, AIList &List);
/// Scan the function and collect all of the ApplyInst with generic
/// substitutions into buckets according to the called function.
void collectApplyInst(SILFunction &F);
/// The driver for the generic specialization pass.
bool specialize(const std::vector<SILFunction *> &BotUpFuncList) {
bool Changed = false;
for (auto &F : *M)
collectApplyInst(F);
// Initialize the worklist with a call-graph bottom-up list of functions.
// We specialize the functions in a top-down order, starting from the end
// of the list.
Worklist.insert(Worklist.begin(),
BotUpFuncList.begin(), BotUpFuncList.end());
while (Worklist.size()) {
SILFunction *F = Worklist.back();
Worklist.pop_back();
if (ApplyInstMap.count(F))
Changed |= specializeApplyInstGroup(F, ApplyInstMap[F]);
}
return Changed;
}
};
} // end anonymous namespace.
void GenericSpecializer::collectApplyInst(SILFunction &F) {
// Don't collect apply inst from transparent functions since we do not want to
// expose shared functions in the mandatory inliner. We will specialize the
// relevant callsites after we inline.
if (F.isTransparent())
return;
// Scan all of the instructions in this function in search of ApplyInsts.
for (auto &BB : F)
for (auto &I : BB) {
ApplyInst *AI = dyn_cast<ApplyInst>(&I);
if (!AI || !AI->hasSubstitutions())
continue;
SILValue CalleeVal = AI->getCallee();
FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(CalleeVal);
if (!FRI)
continue;
SILFunction *Callee = FRI->getReferencedFunction();
if (Callee->isExternalDeclaration())
if (!M->linkFunction(Callee, SILModule::LinkingMode::LinkAll))
continue;
// Save the ApplyInst into the function/bucket that it calls.
ApplyInstMap[Callee].push_back(AI);
}
}
static bool hasSameSubstitutions(ApplyInst *A, ApplyInst *B) {
if (A == B)
return true;
ArrayRef<swift::Substitution> SubsA = A->getSubstitutions();
ArrayRef<swift::Substitution> SubsB = B->getSubstitutions();
if (SubsA.size() != SubsB.size())
return false;
for (int i = 0, e = SubsA.size(); i != e; ++i)
if (SubsA[i] != SubsB[i])
return false;
return true;
}
void dumpTypeSubstitutionMap(const TypeSubstitutionMap &map) {
llvm::errs() << "{\n";
for (auto &kv : map) {
llvm::errs() << " ";
kv.first->print(llvm::errs());
llvm::errs() << " => ";
kv.second->print(llvm::errs());
llvm::errs() << "\n";
}
llvm::errs() << "}\n";
}
bool
GenericSpecializer::specializeApplyInstGroup(SILFunction *F, AIList &List) {
bool Changed = false;
// Make sure we can specialize this function.
if (!canSpecializeFunction(F))
return false;
DEBUG(llvm::dbgs() << "*** Processing: " << F->getName() << "\n");
SmallVector<AIList, 4> Buckets;
// Sort the incoming ApplyInst instructions into multiple buckets of AI with
// exactly the same substitution lists.
for (auto &AI : List) {
bool Placed = false;
DEBUG(llvm::dbgs() << "Function: " << AI->getFunction()->getName() << "; ApplyInst: " << *AI);
// Scan the existing buckets and search for a bucket of the right type.
for (int i = 0, e = Buckets.size(); i < e; ++i) {
assert(Buckets[i].size() && "Found an empty bucket!");
if (hasSameSubstitutions(Buckets[i][0], AI)) {
Buckets[i].push_back(AI);
Placed = true;
break;
}
}
// Continue if the AI is placed in a bucket.
if (Placed)
continue;
// Create a new bucket and place the AI.
Buckets.push_back(AIList());
Buckets[Buckets.size() - 1].push_back(AI);
}
// For each bucket of AI instructions of the same type.
for (auto &Bucket : Buckets) {
assert(Bucket.size() && "Empty bucket!");
DEBUG(llvm::dbgs() << " Bucket: \n");
DEBUG(for (auto *AI : Bucket) {
llvm::dbgs() << " ApplyInst: " << *AI;
});
// Create the substitution maps.
TypeSubstitutionMap InterfaceSubs
= F->getLoweredFunctionType()->getGenericSignature()
->getSubstitutionMap(Bucket[0]->getSubstitutions());
TypeSubstitutionMap ContextSubs
= F->getContextGenericParams()
->getSubstitutionMap(Bucket[0]->getSubstitutions());
// We do not support partial specialization.
if (hasUnboundGenericTypes(InterfaceSubs)) {
DEBUG(llvm::dbgs() << " Can not specialize with interface subs.\n");
continue;
}
llvm::SmallString<64> ClonedName;
{
llvm::raw_svector_ostream buffer(ClonedName);
buffer << "_TTS";
Mangle::Mangler mangle(buffer);
for (auto &Sub : Bucket[0]->getSubstitutions()) {
DEBUG(llvm::dbgs() << " Replacement Type: "; Sub.Replacement->getCanonicalType().dump());
mangle.mangleType(Sub.Replacement->getCanonicalType(),
ResilienceExpansion::Minimal, 0);
for (auto C : Sub.Conformance) {
if (!C)
goto null_conformances;
mangle.mangleProtocolConformance(C);
}
null_conformances:;
buffer << '_';
}
buffer << '_' << F->getName();
}
SILFunction *NewF;
bool createdFunction;
// If we already have this specialization, reuse it.
if (auto PrevF = M->lookUpFunction(ClonedName)) {
NewF = PrevF;
createdFunction = false;
#ifndef NDEBUG
// Make sure that NewF's subst type matches the expected type.
auto Subs = Bucket[0]->getSubstitutions();
auto FTy =
F->getLoweredFunctionType()->substInterfaceGenericArgs(*M,
M->getSwiftModule(),
Subs);
assert(FTy == NewF->getLoweredFunctionType() &&
"Previously specialized function does not match expected type.");
#endif
} else {
// Create a new function.
NewF = SpecializingCloner::cloneFunction(F, InterfaceSubs, ContextSubs,
ClonedName, Bucket[0]);
createdFunction = true;
}
// Replace all of the AI functions with the new function.
for (auto &AI : Bucket)
replaceWithSpecializedFunction(AI, NewF);
Changed = true;
// Analyze the ApplyInsts in the new function.
if (createdFunction) {
collectApplyInst(*NewF);
Worklist.push_back(NewF);
}
}
return Changed;
}
namespace {
class SILGenericSpecializerTransform : public SILModuleTransform {
public:
SILGenericSpecializerTransform() {}
void run() {
CallGraphAnalysis* CGA = PM->getAnalysis<CallGraphAnalysis>();
// Collect a call-graph bottom-up list of functions and specialize the
// functions in reverse order.
bool Changed = GenericSpecializer(getModule()).
specialize(CGA->bottomUpCallGraphOrder());
if (Changed) {
// Schedule another iteration of the transformation pipe.
PM->scheduleAnotherIteration();
// Invalidate the call graph.
invalidateAnalysis(SILAnalysis::InvalidationKind::CallGraph);
}
}
StringRef getName() override { return "Generic Specialization"; }
};
} // end anonymous namespace
SILTransform *swift::createGenericSpecializer() {
return new SILGenericSpecializerTransform();
}