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//===----- CompileOnDemandLayer.cpp - Lazily emit IR on first call --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/Orc/CompileOnDemandLayer.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/FormatVariadic.h"
#include <string>
using namespace llvm;
using namespace llvm::orc;
static ThreadSafeModule extractSubModule(ThreadSafeModule &TSM,
StringRef Suffix,
GVPredicate ShouldExtract) {
auto DeleteExtractedDefs = [](GlobalValue &GV) {
// Bump the linkage: this global will be provided by the external module.
GV.setLinkage(GlobalValue::ExternalLinkage);
// Delete the definition in the source module.
if (isa<Function>(GV)) {
auto &F = cast<Function>(GV);
F.deleteBody();
F.setPersonalityFn(nullptr);
} else if (isa<GlobalVariable>(GV)) {
cast<GlobalVariable>(GV).setInitializer(nullptr);
} else if (isa<GlobalAlias>(GV)) {
// We need to turn deleted aliases into function or variable decls based
// on the type of their aliasee.
auto &A = cast<GlobalAlias>(GV);
Constant *Aliasee = A.getAliasee();
assert(A.hasName() && "Anonymous alias?");
assert(Aliasee->hasName() && "Anonymous aliasee");
std::string AliasName = std::string(A.getName());
if (isa<Function>(Aliasee)) {
auto *F = cloneFunctionDecl(*A.getParent(), *cast<Function>(Aliasee));
A.replaceAllUsesWith(F);
A.eraseFromParent();
F->setName(AliasName);
} else if (isa<GlobalVariable>(Aliasee)) {
auto *G = cloneGlobalVariableDecl(*A.getParent(),
*cast<GlobalVariable>(Aliasee));
A.replaceAllUsesWith(G);
A.eraseFromParent();
G->setName(AliasName);
} else
llvm_unreachable("Alias to unsupported type");
} else
llvm_unreachable("Unsupported global type");
};
auto NewTSM = cloneToNewContext(TSM, ShouldExtract, DeleteExtractedDefs);
NewTSM.withModuleDo([&](Module &M) {
M.setModuleIdentifier((M.getModuleIdentifier() + Suffix).str());
});
return NewTSM;
}
namespace llvm {
namespace orc {
class PartitioningIRMaterializationUnit : public IRMaterializationUnit {
public:
PartitioningIRMaterializationUnit(ExecutionSession &ES,
const IRSymbolMapper::ManglingOptions &MO,
ThreadSafeModule TSM,
CompileOnDemandLayer &Parent)
: IRMaterializationUnit(ES, MO, std::move(TSM)), Parent(Parent) {}
PartitioningIRMaterializationUnit(
ThreadSafeModule TSM, Interface I,
SymbolNameToDefinitionMap SymbolToDefinition,
CompileOnDemandLayer &Parent)
: IRMaterializationUnit(std::move(TSM), std::move(I),
std::move(SymbolToDefinition)),
Parent(Parent) {}
private:
void materialize(std::unique_ptr<MaterializationResponsibility> R) override {
Parent.emitPartition(std::move(R), std::move(TSM),
std::move(SymbolToDefinition));
}
void discard(const JITDylib &V, const SymbolStringPtr &Name) override {
// All original symbols were materialized by the CODLayer and should be
// final. The function bodies provided by M should never be overridden.
llvm_unreachable("Discard should never be called on an "
"ExtractingIRMaterializationUnit");
}
mutable std::mutex SourceModuleMutex;
CompileOnDemandLayer &Parent;
};
std::optional<CompileOnDemandLayer::GlobalValueSet>
CompileOnDemandLayer::compileRequested(GlobalValueSet Requested) {
return std::move(Requested);
}
std::optional<CompileOnDemandLayer::GlobalValueSet>
CompileOnDemandLayer::compileWholeModule(GlobalValueSet Requested) {
return std::nullopt;
}
CompileOnDemandLayer::CompileOnDemandLayer(
ExecutionSession &ES, IRLayer &BaseLayer, LazyCallThroughManager &LCTMgr,
IndirectStubsManagerBuilder BuildIndirectStubsManager)
: IRLayer(ES, BaseLayer.getManglingOptions()), BaseLayer(BaseLayer),
LCTMgr(LCTMgr),
BuildIndirectStubsManager(std::move(BuildIndirectStubsManager)) {}
void CompileOnDemandLayer::setPartitionFunction(PartitionFunction Partition) {
this->Partition = std::move(Partition);
}
void CompileOnDemandLayer::setImplMap(ImplSymbolMap *Imp) {
this->AliaseeImpls = Imp;
}
void CompileOnDemandLayer::emit(
std::unique_ptr<MaterializationResponsibility> R, ThreadSafeModule TSM) {
assert(TSM && "Null module");
auto &ES = getExecutionSession();
// Sort the callables and non-callables, build re-exports and lodge the
// actual module with the implementation dylib.
auto &PDR = getPerDylibResources(R->getTargetJITDylib());
SymbolAliasMap NonCallables;
SymbolAliasMap Callables;
TSM.withModuleDo([&](Module &M) {
// First, do some cleanup on the module:
cleanUpModule(M);
});
for (auto &KV : R->getSymbols()) {
auto &Name = KV.first;
auto &Flags = KV.second;
if (Flags.isCallable())
Callables[Name] = SymbolAliasMapEntry(Name, Flags);
else
NonCallables[Name] = SymbolAliasMapEntry(Name, Flags);
}
// Create a partitioning materialization unit and lodge it with the
// implementation dylib.
if (auto Err = PDR.getImplDylib().define(
std::make_unique<PartitioningIRMaterializationUnit>(
ES, *getManglingOptions(), std::move(TSM), *this))) {
ES.reportError(std::move(Err));
R->failMaterialization();
return;
}
if (!NonCallables.empty())
if (auto Err =
R->replace(reexports(PDR.getImplDylib(), std::move(NonCallables),
JITDylibLookupFlags::MatchAllSymbols))) {
getExecutionSession().reportError(std::move(Err));
R->failMaterialization();
return;
}
if (!Callables.empty()) {
if (auto Err = R->replace(
lazyReexports(LCTMgr, PDR.getISManager(), PDR.getImplDylib(),
std::move(Callables), AliaseeImpls))) {
getExecutionSession().reportError(std::move(Err));
R->failMaterialization();
return;
}
}
}
CompileOnDemandLayer::PerDylibResources &
CompileOnDemandLayer::getPerDylibResources(JITDylib &TargetD) {
std::lock_guard<std::mutex> Lock(CODLayerMutex);
auto I = DylibResources.find(&TargetD);
if (I == DylibResources.end()) {
auto &ImplD =
getExecutionSession().createBareJITDylib(TargetD.getName() + ".impl");
JITDylibSearchOrder NewLinkOrder;
TargetD.withLinkOrderDo([&](const JITDylibSearchOrder &TargetLinkOrder) {
NewLinkOrder = TargetLinkOrder;
});
assert(!NewLinkOrder.empty() && NewLinkOrder.front().first == &TargetD &&
NewLinkOrder.front().second ==
JITDylibLookupFlags::MatchAllSymbols &&
"TargetD must be at the front of its own search order and match "
"non-exported symbol");
NewLinkOrder.insert(std::next(NewLinkOrder.begin()),
{&ImplD, JITDylibLookupFlags::MatchAllSymbols});
ImplD.setLinkOrder(NewLinkOrder, false);
TargetD.setLinkOrder(std::move(NewLinkOrder), false);
PerDylibResources PDR(ImplD, BuildIndirectStubsManager());
I = DylibResources.insert(std::make_pair(&TargetD, std::move(PDR))).first;
}
return I->second;
}
void CompileOnDemandLayer::cleanUpModule(Module &M) {
for (auto &F : M.functions()) {
if (F.isDeclaration())
continue;
if (F.hasAvailableExternallyLinkage()) {
F.deleteBody();
F.setPersonalityFn(nullptr);
continue;
}
}
}
void CompileOnDemandLayer::expandPartition(GlobalValueSet &Partition) {
// Expands the partition to ensure the following rules hold:
// (1) If any alias is in the partition, its aliasee is also in the partition.
// (2) If any aliasee is in the partition, its aliases are also in the
// partiton.
// (3) If any global variable is in the partition then all global variables
// are in the partition.
assert(!Partition.empty() && "Unexpected empty partition");
const Module &M = *(*Partition.begin())->getParent();
bool ContainsGlobalVariables = false;
std::vector<const GlobalValue *> GVsToAdd;
for (const auto *GV : Partition)
if (isa<GlobalAlias>(GV))
GVsToAdd.push_back(
cast<GlobalValue>(cast<GlobalAlias>(GV)->getAliasee()));
else if (isa<GlobalVariable>(GV))
ContainsGlobalVariables = true;
for (auto &A : M.aliases())
if (Partition.count(cast<GlobalValue>(A.getAliasee())))
GVsToAdd.push_back(&A);
if (ContainsGlobalVariables)
for (auto &G : M.globals())
GVsToAdd.push_back(&G);
for (const auto *GV : GVsToAdd)
Partition.insert(GV);
}
void CompileOnDemandLayer::emitPartition(
std::unique_ptr<MaterializationResponsibility> R, ThreadSafeModule TSM,
IRMaterializationUnit::SymbolNameToDefinitionMap Defs) {
// FIXME: Need a 'notify lazy-extracting/emitting' callback to tie the
// extracted module key, extracted module, and source module key
// together. This could be used, for example, to provide a specific
// memory manager instance to the linking layer.
auto &ES = getExecutionSession();
GlobalValueSet RequestedGVs;
for (auto &Name : R->getRequestedSymbols()) {
if (Name == R->getInitializerSymbol())
TSM.withModuleDo([&](Module &M) {
for (auto &GV : getStaticInitGVs(M))
RequestedGVs.insert(&GV);
});
else {
assert(Defs.count(Name) && "No definition for symbol");
RequestedGVs.insert(Defs[Name]);
}
}
/// Perform partitioning with the context lock held, since the partition
/// function is allowed to access the globals to compute the partition.
auto GVsToExtract =
TSM.withModuleDo([&](Module &M) { return Partition(RequestedGVs); });
// Take a 'None' partition to mean the whole module (as opposed to an empty
// partition, which means "materialize nothing"). Emit the whole module
// unmodified to the base layer.
if (GVsToExtract == std::nullopt) {
Defs.clear();
BaseLayer.emit(std::move(R), std::move(TSM));
return;
}
// If the partition is empty, return the whole module to the symbol table.
if (GVsToExtract->empty()) {
if (auto Err =
R->replace(std::make_unique<PartitioningIRMaterializationUnit>(
std::move(TSM),
MaterializationUnit::Interface(R->getSymbols(),
R->getInitializerSymbol()),
std::move(Defs), *this))) {
getExecutionSession().reportError(std::move(Err));
R->failMaterialization();
return;
}
return;
}
// Ok -- we actually need to partition the symbols. Promote the symbol
// linkages/names, expand the partition to include any required symbols
// (i.e. symbols that can't be separated from our partition), and
// then extract the partition.
//
// FIXME: We apply this promotion once per partitioning. It's safe, but
// overkill.
auto ExtractedTSM =
TSM.withModuleDo([&](Module &M) -> Expected<ThreadSafeModule> {
auto PromotedGlobals = PromoteSymbols(M);
if (!PromotedGlobals.empty()) {
MangleAndInterner Mangle(ES, M.getDataLayout());
SymbolFlagsMap SymbolFlags;
IRSymbolMapper::add(ES, *getManglingOptions(),
PromotedGlobals, SymbolFlags);
if (auto Err = R->defineMaterializing(SymbolFlags))
return std::move(Err);
}
expandPartition(*GVsToExtract);
// Submodule name is given by hashing the names of the globals.
std::string SubModuleName;
{
std::vector<const GlobalValue*> HashGVs;
HashGVs.reserve(GVsToExtract->size());
for (const auto *GV : *GVsToExtract)
HashGVs.push_back(GV);
llvm::sort(HashGVs, [](const GlobalValue *LHS, const GlobalValue *RHS) {
return LHS->getName() < RHS->getName();
});
hash_code HC(0);
for (const auto *GV : HashGVs) {
assert(GV->hasName() && "All GVs to extract should be named by now");
auto GVName = GV->getName();
HC = hash_combine(HC, hash_combine_range(GVName.begin(), GVName.end()));
}
raw_string_ostream(SubModuleName)
<< ".submodule."
<< formatv(sizeof(size_t) == 8 ? "{0:x16}" : "{0:x8}",
static_cast<size_t>(HC))
<< ".ll";
}
// Extract the requested partiton (plus any necessary aliases) and
// put the rest back into the impl dylib.
auto ShouldExtract = [&](const GlobalValue &GV) -> bool {
return GVsToExtract->count(&GV);
};
return extractSubModule(TSM, SubModuleName , ShouldExtract);
});
if (!ExtractedTSM) {
ES.reportError(ExtractedTSM.takeError());
R->failMaterialization();
return;
}
if (auto Err = R->replace(std::make_unique<PartitioningIRMaterializationUnit>(
ES, *getManglingOptions(), std::move(TSM), *this))) {
ES.reportError(std::move(Err));
R->failMaterialization();
return;
}
BaseLayer.emit(std::move(R), std::move(*ExtractedTSM));
}
} // end namespace orc
} // end namespace llvm