llvm-project/llvm/unittests/ExecutionEngine/Orc/RTDyldObjectLinkingLayerTest.cpp
Lang Hames 674df13b5f [ORC][JITLink] Add support for weak references, and improve handling of static
libraries.

This patch substantially updates ORCv2's lookup API in order to support weak
references, and to better support static archives. Key changes:

-- Each symbol being looked for is now associated with a SymbolLookupFlags
   value. If the associated value is SymbolLookupFlags::RequiredSymbol then
   the symbol must be defined in one of the JITDylibs being searched (or be
   able to be generated in one of these JITDylibs via an attached definition
   generator) or the lookup will fail with an error. If the associated value is
   SymbolLookupFlags::WeaklyReferencedSymbol then the symbol is permitted to be
   undefined, in which case it will simply not appear in the resulting
   SymbolMap if the rest of the lookup succeeds.

   Since lookup now requires these flags for each symbol, the lookup method now
   takes an instance of a new SymbolLookupSet type rather than a SymbolNameSet.
   SymbolLookupSet is a vector-backed set of (name, flags) pairs. Clients are
   responsible for ensuring that the set property (i.e. unique elements) holds,
   though this is usually simple and SymbolLookupSet provides convenience
   methods to support this.

-- Lookups now have an associated LookupKind value, which is either
   LookupKind::Static or LookupKind::DLSym. Definition generators can inspect
   the lookup kind when determining whether or not to generate new definitions.
   The StaticLibraryDefinitionGenerator is updated to only pull in new objects
   from the archive if the lookup kind is Static. This allows lookup to be
   re-used to emulate dlsym for JIT'd symbols without pulling in new objects
   from archives (which would not happen in a normal dlsym call).

-- JITLink is updated to allow externals to be assigned weak linkage, and
   weak externals now use the SymbolLookupFlags::WeaklyReferencedSymbol value
   for lookups. Unresolved weak references will be assigned the default value of
   zero.

Since this patch was modifying the lookup API anyway, it alo replaces all of the
"MatchNonExported" boolean arguments with a "JITDylibLookupFlags" enum for
readability. If a JITDylib's associated value is
JITDylibLookupFlags::MatchExportedSymbolsOnly then the lookup will only
match against exported (non-hidden) symbols in that JITDylib. If a JITDylib's
associated value is JITDylibLookupFlags::MatchAllSymbols then the lookup will
match against any symbol defined in the JITDylib.
2019-11-28 13:30:49 -08:00

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//===--- RTDyldObjectLinkingLayerTest.cpp - RTDyld linking layer tests ---===//
//
// 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 "OrcTestCommon.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
#include "llvm/ExecutionEngine/Orc/Legacy.h"
#include "llvm/ExecutionEngine/Orc/NullResolver.h"
#include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/LLVMContext.h"
#include "gtest/gtest.h"
using namespace llvm;
using namespace llvm::orc;
namespace {
class RTDyldObjectLinkingLayerExecutionTest : public testing::Test,
public OrcExecutionTest {};
// Adds an object with a debug section to RuntimeDyld and then returns whether
// the debug section was passed to the memory manager.
static bool testSetProcessAllSections(std::unique_ptr<MemoryBuffer> Obj,
bool ProcessAllSections) {
class MemoryManagerWrapper : public SectionMemoryManager {
public:
MemoryManagerWrapper(bool &DebugSeen) : DebugSeen(DebugSeen) {}
uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
unsigned SectionID, StringRef SectionName,
bool IsReadOnly) override {
if (SectionName == ".debug_str")
DebugSeen = true;
return SectionMemoryManager::allocateDataSection(
Size, Alignment, SectionID, SectionName, IsReadOnly);
}
private:
bool &DebugSeen;
};
bool DebugSectionSeen = false;
ExecutionSession ES;
auto &JD = ES.createJITDylib("main");
auto Foo = ES.intern("foo");
RTDyldObjectLinkingLayer ObjLayer(ES, [&DebugSectionSeen]() {
return std::make_unique<MemoryManagerWrapper>(DebugSectionSeen);
});
auto OnResolveDoNothing = [](Expected<SymbolMap> R) {
cantFail(std::move(R));
};
ObjLayer.setProcessAllSections(ProcessAllSections);
cantFail(ObjLayer.add(JD, std::move(Obj), ES.allocateVModule()));
ES.lookup(LookupKind::Static, makeJITDylibSearchOrder(&JD),
SymbolLookupSet(Foo), SymbolState::Resolved, OnResolveDoNothing,
NoDependenciesToRegister);
return DebugSectionSeen;
}
TEST(RTDyldObjectLinkingLayerTest, TestSetProcessAllSections) {
LLVMContext Context;
auto M = std::make_unique<Module>("", Context);
M->setTargetTriple("x86_64-unknown-linux-gnu");
Type *Int32Ty = IntegerType::get(Context, 32);
GlobalVariable *GV =
new GlobalVariable(*M, Int32Ty, false, GlobalValue::ExternalLinkage,
ConstantInt::get(Int32Ty, 42), "foo");
GV->setSection(".debug_str");
// Initialize the native target in case this is the first unit test
// to try to build a TM.
OrcNativeTarget::initialize();
std::unique_ptr<TargetMachine> TM(EngineBuilder().selectTarget(
Triple(M->getTargetTriple()), "", "", SmallVector<std::string, 1>()));
if (!TM)
return;
auto Obj = SimpleCompiler(*TM)(*M);
EXPECT_FALSE(testSetProcessAllSections(
MemoryBuffer::getMemBufferCopy(Obj->getBuffer()), false))
<< "Debug section seen despite ProcessAllSections being false";
EXPECT_TRUE(testSetProcessAllSections(std::move(Obj), true))
<< "Expected to see debug section when ProcessAllSections is true";
}
TEST(RTDyldObjectLinkingLayerTest, TestOverrideObjectFlags) {
OrcNativeTarget::initialize();
std::unique_ptr<TargetMachine> TM(
EngineBuilder().selectTarget(Triple("x86_64-unknown-linux-gnu"), "", "",
SmallVector<std::string, 1>()));
if (!TM)
return;
// Our compiler is going to modify symbol visibility settings without telling
// ORC. This will test our ability to override the flags later.
class FunkySimpleCompiler : public SimpleCompiler {
public:
FunkySimpleCompiler(TargetMachine &TM) : SimpleCompiler(TM) {}
CompileResult operator()(Module &M) {
auto *Foo = M.getFunction("foo");
assert(Foo && "Expected function Foo not found");
Foo->setVisibility(GlobalValue::HiddenVisibility);
return SimpleCompiler::operator()(M);
}
};
// Create a module with two void() functions: foo and bar.
ThreadSafeContext TSCtx(std::make_unique<LLVMContext>());
ThreadSafeModule M;
{
ModuleBuilder MB(*TSCtx.getContext(), TM->getTargetTriple().str(), "dummy");
MB.getModule()->setDataLayout(TM->createDataLayout());
Function *FooImpl = MB.createFunctionDecl(
FunctionType::get(Type::getVoidTy(*TSCtx.getContext()), {}, false),
"foo");
BasicBlock *FooEntry =
BasicBlock::Create(*TSCtx.getContext(), "entry", FooImpl);
IRBuilder<> B1(FooEntry);
B1.CreateRetVoid();
Function *BarImpl = MB.createFunctionDecl(
FunctionType::get(Type::getVoidTy(*TSCtx.getContext()), {}, false),
"bar");
BasicBlock *BarEntry =
BasicBlock::Create(*TSCtx.getContext(), "entry", BarImpl);
IRBuilder<> B2(BarEntry);
B2.CreateRetVoid();
M = ThreadSafeModule(MB.takeModule(), std::move(TSCtx));
}
// Create a simple stack and set the override flags option.
ExecutionSession ES;
auto &JD = ES.createJITDylib("main");
auto Foo = ES.intern("foo");
RTDyldObjectLinkingLayer ObjLayer(
ES, []() { return std::make_unique<SectionMemoryManager>(); });
IRCompileLayer CompileLayer(ES, ObjLayer, FunkySimpleCompiler(*TM));
ObjLayer.setOverrideObjectFlagsWithResponsibilityFlags(true);
cantFail(CompileLayer.add(JD, std::move(M), ES.allocateVModule()));
ES.lookup(
LookupKind::Static, makeJITDylibSearchOrder(&JD), SymbolLookupSet(Foo),
SymbolState::Resolved,
[](Expected<SymbolMap> R) { cantFail(std::move(R)); },
NoDependenciesToRegister);
}
TEST(RTDyldObjectLinkingLayerTest, TestAutoClaimResponsibilityForSymbols) {
OrcNativeTarget::initialize();
std::unique_ptr<TargetMachine> TM(
EngineBuilder().selectTarget(Triple("x86_64-unknown-linux-gnu"), "", "",
SmallVector<std::string, 1>()));
if (!TM)
return;
// Our compiler is going to add a new symbol without telling ORC.
// This will test our ability to auto-claim responsibility later.
class FunkySimpleCompiler : public SimpleCompiler {
public:
FunkySimpleCompiler(TargetMachine &TM) : SimpleCompiler(TM) {}
CompileResult operator()(Module &M) {
Function *BarImpl = Function::Create(
FunctionType::get(Type::getVoidTy(M.getContext()), {}, false),
GlobalValue::ExternalLinkage, "bar", &M);
BasicBlock *BarEntry =
BasicBlock::Create(M.getContext(), "entry", BarImpl);
IRBuilder<> B(BarEntry);
B.CreateRetVoid();
return SimpleCompiler::operator()(M);
}
};
// Create a module with two void() functions: foo and bar.
ThreadSafeContext TSCtx(std::make_unique<LLVMContext>());
ThreadSafeModule M;
{
ModuleBuilder MB(*TSCtx.getContext(), TM->getTargetTriple().str(), "dummy");
MB.getModule()->setDataLayout(TM->createDataLayout());
Function *FooImpl = MB.createFunctionDecl(
FunctionType::get(Type::getVoidTy(*TSCtx.getContext()), {}, false),
"foo");
BasicBlock *FooEntry =
BasicBlock::Create(*TSCtx.getContext(), "entry", FooImpl);
IRBuilder<> B(FooEntry);
B.CreateRetVoid();
M = ThreadSafeModule(MB.takeModule(), std::move(TSCtx));
}
// Create a simple stack and set the override flags option.
ExecutionSession ES;
auto &JD = ES.createJITDylib("main");
auto Foo = ES.intern("foo");
RTDyldObjectLinkingLayer ObjLayer(
ES, []() { return std::make_unique<SectionMemoryManager>(); });
IRCompileLayer CompileLayer(ES, ObjLayer, FunkySimpleCompiler(*TM));
ObjLayer.setAutoClaimResponsibilityForObjectSymbols(true);
cantFail(CompileLayer.add(JD, std::move(M), ES.allocateVModule()));
ES.lookup(
LookupKind::Static, makeJITDylibSearchOrder(&JD), SymbolLookupSet(Foo),
SymbolState::Resolved,
[](Expected<SymbolMap> R) { cantFail(std::move(R)); },
NoDependenciesToRegister);
}
} // end anonymous namespace