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llvm-project/llvm/lib/ExecutionEngine/Orc/ELFNixPlatform.cpp

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//===------ ELFNixPlatform.cpp - Utilities for executing MachO in Orc -----===//
//
// 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/ELFNixPlatform.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/ExecutionEngine/JITLink/ELF_x86_64.h"
#include "llvm/ExecutionEngine/JITLink/x86_64.h"
#include "llvm/ExecutionEngine/Orc/DebugUtils.h"
#include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
#include "llvm/Support/BinaryByteStream.h"
#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "orc"
using namespace llvm;
using namespace llvm::orc;
using namespace llvm::orc::shared;
namespace {
class DSOHandleMaterializationUnit : public MaterializationUnit {
public:
DSOHandleMaterializationUnit(ELFNixPlatform &ENP,
const SymbolStringPtr &DSOHandleSymbol)
: MaterializationUnit(
createDSOHandleSectionInterface(ENP, DSOHandleSymbol)),
ENP(ENP) {}
StringRef getName() const override { return "DSOHandleMU"; }
void materialize(std::unique_ptr<MaterializationResponsibility> R) override {
unsigned PointerSize;
support::endianness Endianness;
jitlink::Edge::Kind EdgeKind;
const auto &TT =
ENP.getExecutionSession().getExecutorProcessControl().getTargetTriple();
switch (TT.getArch()) {
case Triple::x86_64:
PointerSize = 8;
Endianness = support::endianness::little;
EdgeKind = jitlink::x86_64::Pointer64;
break;
default:
llvm_unreachable("Unrecognized architecture");
}
// void *__dso_handle = &__dso_handle;
auto G = std::make_unique<jitlink::LinkGraph>(
"<DSOHandleMU>", TT, PointerSize, Endianness,
jitlink::getGenericEdgeKindName);
auto &DSOHandleSection =
G->createSection(".data.__dso_handle", jitlink::MemProt::Read);
auto &DSOHandleBlock = G->createContentBlock(
DSOHandleSection, getDSOHandleContent(PointerSize), orc::ExecutorAddr(),
8, 0);
auto &DSOHandleSymbol = G->addDefinedSymbol(
DSOHandleBlock, 0, *R->getInitializerSymbol(), DSOHandleBlock.getSize(),
jitlink::Linkage::Strong, jitlink::Scope::Default, false, true);
DSOHandleBlock.addEdge(EdgeKind, 0, DSOHandleSymbol, 0);
ENP.getObjectLinkingLayer().emit(std::move(R), std::move(G));
}
void discard(const JITDylib &JD, const SymbolStringPtr &Sym) override {}
private:
static MaterializationUnit::Interface
createDSOHandleSectionInterface(ELFNixPlatform &ENP,
const SymbolStringPtr &DSOHandleSymbol) {
SymbolFlagsMap SymbolFlags;
SymbolFlags[DSOHandleSymbol] = JITSymbolFlags::Exported;
return MaterializationUnit::Interface(std::move(SymbolFlags),
DSOHandleSymbol);
}
ArrayRef<char> getDSOHandleContent(size_t PointerSize) {
static const char Content[8] = {0};
assert(PointerSize <= sizeof Content);
return {Content, PointerSize};
}
ELFNixPlatform &ENP;
};
StringRef EHFrameSectionName = ".eh_frame";
StringRef InitArrayFuncSectionName = ".init_array";
StringRef ThreadBSSSectionName = ".tbss";
StringRef ThreadDataSectionName = ".tdata";
StringRef InitSectionNames[] = {InitArrayFuncSectionName};
} // end anonymous namespace
namespace llvm {
namespace orc {
Expected<std::unique_ptr<ELFNixPlatform>>
ELFNixPlatform::Create(ExecutionSession &ES,
ObjectLinkingLayer &ObjLinkingLayer,
JITDylib &PlatformJD, const char *OrcRuntimePath,
Optional<SymbolAliasMap> RuntimeAliases) {
auto &EPC = ES.getExecutorProcessControl();
// If the target is not supported then bail out immediately.
if (!supportedTarget(EPC.getTargetTriple()))
return make_error<StringError>("Unsupported ELFNixPlatform triple: " +
EPC.getTargetTriple().str(),
inconvertibleErrorCode());
// Create default aliases if the caller didn't supply any.
if (!RuntimeAliases)
RuntimeAliases = standardPlatformAliases(ES);
// Define the aliases.
if (auto Err = PlatformJD.define(symbolAliases(std::move(*RuntimeAliases))))
return std::move(Err);
// Add JIT-dispatch function support symbols.
if (auto Err = PlatformJD.define(absoluteSymbols(
{{ES.intern("__orc_rt_jit_dispatch"),
{EPC.getJITDispatchInfo().JITDispatchFunction.getValue(),
JITSymbolFlags::Exported}},
{ES.intern("__orc_rt_jit_dispatch_ctx"),
{EPC.getJITDispatchInfo().JITDispatchContext.getValue(),
JITSymbolFlags::Exported}}})))
return std::move(Err);
// Create a generator for the ORC runtime archive.
auto OrcRuntimeArchiveGenerator = StaticLibraryDefinitionGenerator::Load(
ObjLinkingLayer, OrcRuntimePath, EPC.getTargetTriple());
if (!OrcRuntimeArchiveGenerator)
return OrcRuntimeArchiveGenerator.takeError();
// Create the instance.
Error Err = Error::success();
auto P = std::unique_ptr<ELFNixPlatform>(
new ELFNixPlatform(ES, ObjLinkingLayer, PlatformJD,
std::move(*OrcRuntimeArchiveGenerator), Err));
if (Err)
return std::move(Err);
return std::move(P);
}
Error ELFNixPlatform::setupJITDylib(JITDylib &JD) {
return JD.define(
std::make_unique<DSOHandleMaterializationUnit>(*this, DSOHandleSymbol));
}
Error ELFNixPlatform::teardownJITDylib(JITDylib &JD) {
return Error::success();
}
Error ELFNixPlatform::notifyAdding(ResourceTracker &RT,
const MaterializationUnit &MU) {
auto &JD = RT.getJITDylib();
const auto &InitSym = MU.getInitializerSymbol();
if (!InitSym)
return Error::success();
RegisteredInitSymbols[&JD].add(InitSym,
SymbolLookupFlags::WeaklyReferencedSymbol);
LLVM_DEBUG({
dbgs() << "ELFNixPlatform: Registered init symbol " << *InitSym
<< " for MU " << MU.getName() << "\n";
});
return Error::success();
}
Error ELFNixPlatform::notifyRemoving(ResourceTracker &RT) {
llvm_unreachable("Not supported yet");
}
static void addAliases(ExecutionSession &ES, SymbolAliasMap &Aliases,
ArrayRef<std::pair<const char *, const char *>> AL) {
for (auto &KV : AL) {
auto AliasName = ES.intern(KV.first);
assert(!Aliases.count(AliasName) && "Duplicate symbol name in alias map");
Aliases[std::move(AliasName)] = {ES.intern(KV.second),
JITSymbolFlags::Exported};
}
}
SymbolAliasMap ELFNixPlatform::standardPlatformAliases(ExecutionSession &ES) {
SymbolAliasMap Aliases;
addAliases(ES, Aliases, requiredCXXAliases());
addAliases(ES, Aliases, standardRuntimeUtilityAliases());
return Aliases;
}
ArrayRef<std::pair<const char *, const char *>>
ELFNixPlatform::requiredCXXAliases() {
static const std::pair<const char *, const char *> RequiredCXXAliases[] = {
{"__cxa_atexit", "__orc_rt_elfnix_cxa_atexit"},
{"atexit", "__orc_rt_elfnix_atexit"}};
return ArrayRef<std::pair<const char *, const char *>>(RequiredCXXAliases);
}
ArrayRef<std::pair<const char *, const char *>>
ELFNixPlatform::standardRuntimeUtilityAliases() {
static const std::pair<const char *, const char *>
StandardRuntimeUtilityAliases[] = {
{"__orc_rt_run_program", "__orc_rt_elfnix_run_program"},
{"__orc_rt_log_error", "__orc_rt_log_error_to_stderr"}};
return ArrayRef<std::pair<const char *, const char *>>(
StandardRuntimeUtilityAliases);
}
bool ELFNixPlatform::isInitializerSection(StringRef SecName) {
for (auto &Name : InitSectionNames) {
if (Name.equals(SecName))
return true;
}
return false;
}
bool ELFNixPlatform::supportedTarget(const Triple &TT) {
switch (TT.getArch()) {
case Triple::x86_64:
return true;
default:
return false;
}
}
ELFNixPlatform::ELFNixPlatform(
ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer,
JITDylib &PlatformJD,
std::unique_ptr<DefinitionGenerator> OrcRuntimeGenerator, Error &Err)
: ES(ES), ObjLinkingLayer(ObjLinkingLayer),
DSOHandleSymbol(ES.intern("__dso_handle")) {
ErrorAsOutParameter _(&Err);
ObjLinkingLayer.addPlugin(std::make_unique<ELFNixPlatformPlugin>(*this));
PlatformJD.addGenerator(std::move(OrcRuntimeGenerator));
// PlatformJD hasn't been 'set-up' by the platform yet (since we're creating
// the platform now), so set it up.
if (auto E2 = setupJITDylib(PlatformJD)) {
Err = std::move(E2);
return;
}
RegisteredInitSymbols[&PlatformJD].add(
DSOHandleSymbol, SymbolLookupFlags::WeaklyReferencedSymbol);
// Associate wrapper function tags with JIT-side function implementations.
if (auto E2 = associateRuntimeSupportFunctions(PlatformJD)) {
Err = std::move(E2);
return;
}
// Lookup addresses of runtime functions callable by the platform,
// call the platform bootstrap function to initialize the platform-state
// object in the executor.
if (auto E2 = bootstrapELFNixRuntime(PlatformJD)) {
Err = std::move(E2);
return;
}
}
Error ELFNixPlatform::associateRuntimeSupportFunctions(JITDylib &PlatformJD) {
ExecutionSession::JITDispatchHandlerAssociationMap WFs;
using GetInitializersSPSSig =
SPSExpected<SPSELFNixJITDylibInitializerSequence>(SPSString);
WFs[ES.intern("__orc_rt_elfnix_get_initializers_tag")] =
ES.wrapAsyncWithSPS<GetInitializersSPSSig>(
this, &ELFNixPlatform::rt_getInitializers);
using GetDeinitializersSPSSig =
SPSExpected<SPSELFJITDylibDeinitializerSequence>(SPSExecutorAddr);
WFs[ES.intern("__orc_rt_elfnix_get_deinitializers_tag")] =
ES.wrapAsyncWithSPS<GetDeinitializersSPSSig>(
this, &ELFNixPlatform::rt_getDeinitializers);
using LookupSymbolSPSSig =
SPSExpected<SPSExecutorAddr>(SPSExecutorAddr, SPSString);
WFs[ES.intern("__orc_rt_elfnix_symbol_lookup_tag")] =
ES.wrapAsyncWithSPS<LookupSymbolSPSSig>(this,
&ELFNixPlatform::rt_lookupSymbol);
return ES.registerJITDispatchHandlers(PlatformJD, std::move(WFs));
}
void ELFNixPlatform::getInitializersBuildSequencePhase(
SendInitializerSequenceFn SendResult, JITDylib &JD,
std::vector<JITDylibSP> DFSLinkOrder) {
ELFNixJITDylibInitializerSequence FullInitSeq;
{
std::lock_guard<std::mutex> Lock(PlatformMutex);
for (auto &InitJD : reverse(DFSLinkOrder)) {
LLVM_DEBUG({
dbgs() << "ELFNixPlatform: Appending inits for \"" << InitJD->getName()
<< "\" to sequence\n";
});
auto ISItr = InitSeqs.find(InitJD.get());
if (ISItr != InitSeqs.end()) {
FullInitSeq.emplace_back(std::move(ISItr->second));
InitSeqs.erase(ISItr);
}
}
}
SendResult(std::move(FullInitSeq));
}
void ELFNixPlatform::getInitializersLookupPhase(
SendInitializerSequenceFn SendResult, JITDylib &JD) {
auto DFSLinkOrder = JD.getDFSLinkOrder();
DenseMap<JITDylib *, SymbolLookupSet> NewInitSymbols;
ES.runSessionLocked([&]() {
for (auto &InitJD : DFSLinkOrder) {
auto RISItr = RegisteredInitSymbols.find(InitJD.get());
if (RISItr != RegisteredInitSymbols.end()) {
NewInitSymbols[InitJD.get()] = std::move(RISItr->second);
RegisteredInitSymbols.erase(RISItr);
}
}
});
// If there are no further init symbols to look up then move on to the next
// phase.
if (NewInitSymbols.empty()) {
getInitializersBuildSequencePhase(std::move(SendResult), JD,
std::move(DFSLinkOrder));
return;
}
// Otherwise issue a lookup and re-run this phase when it completes.
lookupInitSymbolsAsync(
[this, SendResult = std::move(SendResult), &JD](Error Err) mutable {
if (Err)
SendResult(std::move(Err));
else
getInitializersLookupPhase(std::move(SendResult), JD);
},
ES, std::move(NewInitSymbols));
}
void ELFNixPlatform::rt_getInitializers(SendInitializerSequenceFn SendResult,
StringRef JDName) {
LLVM_DEBUG({
dbgs() << "ELFNixPlatform::rt_getInitializers(\"" << JDName << "\")\n";
});
JITDylib *JD = ES.getJITDylibByName(JDName);
if (!JD) {
LLVM_DEBUG({
dbgs() << " No such JITDylib \"" << JDName << "\". Sending error.\n";
});
SendResult(make_error<StringError>("No JITDylib named " + JDName,
inconvertibleErrorCode()));
return;
}
getInitializersLookupPhase(std::move(SendResult), *JD);
}
void ELFNixPlatform::rt_getDeinitializers(
SendDeinitializerSequenceFn SendResult, ExecutorAddr Handle) {
LLVM_DEBUG({
dbgs() << "ELFNixPlatform::rt_getDeinitializers(\""
<< formatv("{0:x}", Handle.getValue()) << "\")\n";
});
JITDylib *JD = nullptr;
{
std::lock_guard<std::mutex> Lock(PlatformMutex);
auto I = HandleAddrToJITDylib.find(Handle);
if (I != HandleAddrToJITDylib.end())
JD = I->second;
}
if (!JD) {
LLVM_DEBUG({
dbgs() << " No JITDylib for handle "
<< formatv("{0:x}", Handle.getValue()) << "\n";
});
SendResult(make_error<StringError>("No JITDylib associated with handle " +
formatv("{0:x}", Handle.getValue()),
inconvertibleErrorCode()));
return;
}
SendResult(ELFNixJITDylibDeinitializerSequence());
}
void ELFNixPlatform::rt_lookupSymbol(SendSymbolAddressFn SendResult,
ExecutorAddr Handle,
StringRef SymbolName) {
LLVM_DEBUG({
dbgs() << "ELFNixPlatform::rt_lookupSymbol(\""
<< formatv("{0:x}", Handle.getValue()) << "\")\n";
});
JITDylib *JD = nullptr;
{
std::lock_guard<std::mutex> Lock(PlatformMutex);
auto I = HandleAddrToJITDylib.find(Handle);
if (I != HandleAddrToJITDylib.end())
JD = I->second;
}
if (!JD) {
LLVM_DEBUG({
dbgs() << " No JITDylib for handle "
<< formatv("{0:x}", Handle.getValue()) << "\n";
});
SendResult(make_error<StringError>("No JITDylib associated with handle " +
formatv("{0:x}", Handle.getValue()),
inconvertibleErrorCode()));
return;
}
// Use functor class to work around XL build compiler issue on AIX.
class RtLookupNotifyComplete {
public:
RtLookupNotifyComplete(SendSymbolAddressFn &&SendResult)
: SendResult(std::move(SendResult)) {}
void operator()(Expected<SymbolMap> Result) {
if (Result) {
assert(Result->size() == 1 && "Unexpected result map count");
SendResult(ExecutorAddr(Result->begin()->second.getAddress()));
} else {
SendResult(Result.takeError());
}
}
private:
SendSymbolAddressFn SendResult;
};
ES.lookup(
LookupKind::DLSym, {{JD, JITDylibLookupFlags::MatchExportedSymbolsOnly}},
SymbolLookupSet(ES.intern(SymbolName)), SymbolState::Ready,
RtLookupNotifyComplete(std::move(SendResult)), NoDependenciesToRegister);
}
Error ELFNixPlatform::bootstrapELFNixRuntime(JITDylib &PlatformJD) {
std::pair<const char *, ExecutorAddr *> Symbols[] = {
{"__orc_rt_elfnix_platform_bootstrap", &orc_rt_elfnix_platform_bootstrap},
{"__orc_rt_elfnix_platform_shutdown", &orc_rt_elfnix_platform_shutdown},
{"__orc_rt_elfnix_register_object_sections",
&orc_rt_elfnix_register_object_sections},
{"__orc_rt_elfnix_create_pthread_key",
&orc_rt_elfnix_create_pthread_key}};
SymbolLookupSet RuntimeSymbols;
std::vector<std::pair<SymbolStringPtr, ExecutorAddr *>> AddrsToRecord;
for (const auto &KV : Symbols) {
auto Name = ES.intern(KV.first);
RuntimeSymbols.add(Name);
AddrsToRecord.push_back({std::move(Name), KV.second});
}
auto RuntimeSymbolAddrs = ES.lookup(
{{&PlatformJD, JITDylibLookupFlags::MatchAllSymbols}}, RuntimeSymbols);
if (!RuntimeSymbolAddrs)
return RuntimeSymbolAddrs.takeError();
for (const auto &KV : AddrsToRecord) {
auto &Name = KV.first;
assert(RuntimeSymbolAddrs->count(Name) && "Missing runtime symbol?");
KV.second->setValue((*RuntimeSymbolAddrs)[Name].getAddress());
}
auto PJDDSOHandle = ES.lookup(
{{&PlatformJD, JITDylibLookupFlags::MatchAllSymbols}}, DSOHandleSymbol);
if (!PJDDSOHandle)
return PJDDSOHandle.takeError();
if (auto Err = ES.callSPSWrapper<void(uint64_t)>(
orc_rt_elfnix_platform_bootstrap, PJDDSOHandle->getAddress()))
return Err;
// FIXME: Ordering is fuzzy here. We're probably best off saying
// "behavior is undefined if code that uses the runtime is added before
// the platform constructor returns", then move all this to the constructor.
RuntimeBootstrapped = true;
std::vector<ELFPerObjectSectionsToRegister> DeferredPOSRs;
{
std::lock_guard<std::mutex> Lock(PlatformMutex);
DeferredPOSRs = std::move(BootstrapPOSRs);
}
for (auto &D : DeferredPOSRs)
if (auto Err = registerPerObjectSections(D))
return Err;
return Error::success();
}
Error ELFNixPlatform::registerInitInfo(
JITDylib &JD, ArrayRef<jitlink::Section *> InitSections) {
std::unique_lock<std::mutex> Lock(PlatformMutex);
ELFNixJITDylibInitializers *InitSeq = nullptr;
{
auto I = InitSeqs.find(&JD);
if (I == InitSeqs.end()) {
// If there's no init sequence entry yet then we need to look up the
// header symbol to force creation of one.
Lock.unlock();
auto SearchOrder =
JD.withLinkOrderDo([](const JITDylibSearchOrder &SO) { return SO; });
if (auto Err = ES.lookup(SearchOrder, DSOHandleSymbol).takeError())
return Err;
Lock.lock();
I = InitSeqs.find(&JD);
assert(I != InitSeqs.end() &&
"Entry missing after header symbol lookup?");
}
InitSeq = &I->second;
}
for (auto *Sec : InitSections) {
// FIXME: Avoid copy here.
jitlink::SectionRange R(*Sec);
InitSeq->InitSections[Sec->getName()].push_back(
{ExecutorAddr(R.getStart()), ExecutorAddr(R.getEnd())});
}
return Error::success();
}
Error ELFNixPlatform::registerPerObjectSections(
const ELFPerObjectSectionsToRegister &POSR) {
if (!orc_rt_elfnix_register_object_sections)
return make_error<StringError>("Attempting to register per-object "
"sections, but runtime support has not "
"been loaded yet",
inconvertibleErrorCode());
Error ErrResult = Error::success();
if (auto Err = ES.callSPSWrapper<shared::SPSError(
SPSELFPerObjectSectionsToRegister)>(
orc_rt_elfnix_register_object_sections, ErrResult, POSR))
return Err;
return ErrResult;
}
Expected<uint64_t> ELFNixPlatform::createPThreadKey() {
if (!orc_rt_elfnix_create_pthread_key)
return make_error<StringError>(
"Attempting to create pthread key in target, but runtime support has "
"not been loaded yet",
inconvertibleErrorCode());
Expected<uint64_t> Result(0);
if (auto Err = ES.callSPSWrapper<SPSExpected<uint64_t>(void)>(
orc_rt_elfnix_create_pthread_key, Result))
return std::move(Err);
return Result;
}
void ELFNixPlatform::ELFNixPlatformPlugin::modifyPassConfig(
MaterializationResponsibility &MR, jitlink::LinkGraph &LG,
jitlink::PassConfiguration &Config) {
// If the initializer symbol is the __dso_handle symbol then just add
// the DSO handle support passes.
if (MR.getInitializerSymbol() == MP.DSOHandleSymbol) {
addDSOHandleSupportPasses(MR, Config);
// The DSOHandle materialization unit doesn't require any other
// support, so we can bail out early.
return;
}
// If the object contains initializers then add passes to record them.
if (MR.getInitializerSymbol())
addInitializerSupportPasses(MR, Config);
// Add passes for eh-frame and TLV support.
addEHAndTLVSupportPasses(MR, Config);
}
ObjectLinkingLayer::Plugin::SyntheticSymbolDependenciesMap
ELFNixPlatform::ELFNixPlatformPlugin::getSyntheticSymbolDependencies(
MaterializationResponsibility &MR) {
std::lock_guard<std::mutex> Lock(PluginMutex);
auto I = InitSymbolDeps.find(&MR);
if (I != InitSymbolDeps.end()) {
SyntheticSymbolDependenciesMap Result;
Result[MR.getInitializerSymbol()] = std::move(I->second);
InitSymbolDeps.erase(&MR);
return Result;
}
return SyntheticSymbolDependenciesMap();
}
void ELFNixPlatform::ELFNixPlatformPlugin::addInitializerSupportPasses(
MaterializationResponsibility &MR, jitlink::PassConfiguration &Config) {
/// Preserve init sections.
Config.PrePrunePasses.push_back([this, &MR](jitlink::LinkGraph &G) -> Error {
if (auto Err = preserveInitSections(G, MR))
return Err;
return Error::success();
});
Config.PostFixupPasses.push_back(
[this, &JD = MR.getTargetJITDylib()](jitlink::LinkGraph &G) {
return registerInitSections(G, JD);
});
}
void ELFNixPlatform::ELFNixPlatformPlugin::addDSOHandleSupportPasses(
MaterializationResponsibility &MR, jitlink::PassConfiguration &Config) {
Config.PostAllocationPasses.push_back([this, &JD = MR.getTargetJITDylib()](
jitlink::LinkGraph &G) -> Error {
auto I = llvm::find_if(G.defined_symbols(), [this](jitlink::Symbol *Sym) {
return Sym->getName() == *MP.DSOHandleSymbol;
});
assert(I != G.defined_symbols().end() && "Missing DSO handle symbol");
{
std::lock_guard<std::mutex> Lock(MP.PlatformMutex);
auto HandleAddr = (*I)->getAddress();
MP.HandleAddrToJITDylib[HandleAddr] = &JD;
assert(!MP.InitSeqs.count(&JD) && "InitSeq entry for JD already exists");
MP.InitSeqs.insert(std::make_pair(
&JD, ELFNixJITDylibInitializers(JD.getName(), HandleAddr)));
}
return Error::success();
});
}
void ELFNixPlatform::ELFNixPlatformPlugin::addEHAndTLVSupportPasses(
MaterializationResponsibility &MR, jitlink::PassConfiguration &Config) {
// Insert TLV lowering at the start of the PostPrunePasses, since we want
// it to run before GOT/PLT lowering.
// TODO: Check that before the fixTLVSectionsAndEdges pass, the GOT/PLT build
// pass has done. Because the TLS descriptor need to be allocate in GOT.
Config.PostPrunePasses.push_back(
[this, &JD = MR.getTargetJITDylib()](jitlink::LinkGraph &G) {
return fixTLVSectionsAndEdges(G, JD);
});
// Add a pass to register the final addresses of the eh-frame and TLV sections
// with the runtime.
Config.PostFixupPasses.push_back([this](jitlink::LinkGraph &G) -> Error {
ELFPerObjectSectionsToRegister POSR;
if (auto *EHFrameSection = G.findSectionByName(EHFrameSectionName)) {
jitlink::SectionRange R(*EHFrameSection);
if (!R.empty())
POSR.EHFrameSection = {ExecutorAddr(R.getStart()),
ExecutorAddr(R.getEnd())};
}
// Get a pointer to the thread data section if there is one. It will be used
// below.
jitlink::Section *ThreadDataSection =
G.findSectionByName(ThreadDataSectionName);
// Handle thread BSS section if there is one.
if (auto *ThreadBSSSection = G.findSectionByName(ThreadBSSSectionName)) {
// If there's already a thread data section in this graph then merge the
// thread BSS section content into it, otherwise just treat the thread
// BSS section as the thread data section.
if (ThreadDataSection)
G.mergeSections(*ThreadDataSection, *ThreadBSSSection);
else
ThreadDataSection = ThreadBSSSection;
}
// Having merged thread BSS (if present) and thread data (if present),
// record the resulting section range.
if (ThreadDataSection) {
jitlink::SectionRange R(*ThreadDataSection);
if (!R.empty())
POSR.ThreadDataSection = {ExecutorAddr(R.getStart()),
ExecutorAddr(R.getEnd())};
}
if (POSR.EHFrameSection.Start || POSR.ThreadDataSection.Start) {
// If we're still bootstrapping the runtime then just record this
// frame for now.
if (!MP.RuntimeBootstrapped) {
std::lock_guard<std::mutex> Lock(MP.PlatformMutex);
MP.BootstrapPOSRs.push_back(POSR);
return Error::success();
}
// Otherwise register it immediately.
if (auto Err = MP.registerPerObjectSections(POSR))
return Err;
}
return Error::success();
});
}
Error ELFNixPlatform::ELFNixPlatformPlugin::preserveInitSections(
jitlink::LinkGraph &G, MaterializationResponsibility &MR) {
JITLinkSymbolSet InitSectionSymbols;
for (auto &InitSectionName : InitSectionNames) {
// Skip non-init sections.
auto *InitSection = G.findSectionByName(InitSectionName);
if (!InitSection)
continue;
// Make a pass over live symbols in the section: those blocks are already
// preserved.
DenseSet<jitlink::Block *> AlreadyLiveBlocks;
for (auto &Sym : InitSection->symbols()) {
auto &B = Sym->getBlock();
if (Sym->isLive() && Sym->getOffset() == 0 &&
Sym->getSize() == B.getSize() && !AlreadyLiveBlocks.count(&B)) {
InitSectionSymbols.insert(Sym);
AlreadyLiveBlocks.insert(&B);
}
}
// Add anonymous symbols to preserve any not-already-preserved blocks.
for (auto *B : InitSection->blocks())
if (!AlreadyLiveBlocks.count(B))
InitSectionSymbols.insert(
&G.addAnonymousSymbol(*B, 0, B->getSize(), false, true));
}
if (!InitSectionSymbols.empty()) {
std::lock_guard<std::mutex> Lock(PluginMutex);
InitSymbolDeps[&MR] = std::move(InitSectionSymbols);
}
return Error::success();
}
Error ELFNixPlatform::ELFNixPlatformPlugin::registerInitSections(
jitlink::LinkGraph &G, JITDylib &JD) {
SmallVector<jitlink::Section *> InitSections;
LLVM_DEBUG({ dbgs() << "ELFNixPlatform::registerInitSections\n"; });
for (auto InitSectionName : InitSectionNames) {
if (auto *Sec = G.findSectionByName(InitSectionName)) {
InitSections.push_back(Sec);
}
}
// Dump the scraped inits.
LLVM_DEBUG({
dbgs() << "ELFNixPlatform: Scraped " << G.getName() << " init sections:\n";
for (auto *Sec : InitSections) {
jitlink::SectionRange R(*Sec);
dbgs() << " " << Sec->getName() << ": "
<< formatv("[ {0:x} -- {1:x} ]", R.getStart(), R.getEnd()) << "\n";
}
});
return MP.registerInitInfo(JD, InitSections);
}
Error ELFNixPlatform::ELFNixPlatformPlugin::fixTLVSectionsAndEdges(
jitlink::LinkGraph &G, JITDylib &JD) {
// TODO implement TLV support
for (auto *Sym : G.external_symbols())
if (Sym->getName() == "__tls_get_addr") {
Sym->setName("___orc_rt_elfnix_tls_get_addr");
}
auto *TLSInfoEntrySection = G.findSectionByName("$__TLSINFO");
if (TLSInfoEntrySection) {
Optional<uint64_t> Key;
{
std::lock_guard<std::mutex> Lock(MP.PlatformMutex);
auto I = MP.JITDylibToPThreadKey.find(&JD);
if (I != MP.JITDylibToPThreadKey.end())
Key = I->second;
}
if (!Key) {
if (auto KeyOrErr = MP.createPThreadKey())
Key = *KeyOrErr;
else
return KeyOrErr.takeError();
}
uint64_t PlatformKeyBits =
support::endian::byte_swap(*Key, G.getEndianness());
for (auto *B : TLSInfoEntrySection->blocks()) {
// FIXME: The TLS descriptor byte length may different with different
// ISA
assert(B->getSize() == (G.getPointerSize() * 2) &&
"TLS descriptor must be 2 words length");
auto TLSInfoEntryContent = B->getMutableContent(G);
memcpy(TLSInfoEntryContent.data(), &PlatformKeyBits, G.getPointerSize());
}
}
return Error::success();
}
} // End namespace orc.
} // End namespace llvm.
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