llvm/unittests/Linker/LinkModulesTest.cpp
Duncan P. N. Exon Smith 268a755585 Linker: Move distinct MDNodes instead of cloning
Instead of cloning distinct `MDNode`s when linking in a module, just
move them over.  The module linker destroys the source module, so the
old node would otherwise just be leaked on the context.  Create the new
node in place.  This also reduces the number of cloned uniqued nodes
(since it's less likely their operands have changed).

This mapping strategy is only correct when we're discarding the source,
so the linker turns it on via a ValueMapper flag, `RF_MoveDistinctMDs`.

There's nothing observable in terms of `llvm-link` output here: the
linked module should be semantically identical.

I'll be adding more 'distinct' nodes to the debug info metadata graph in
order to break uniquing cycles, so the benefits of this will partly come
in future commits.  However, we should get some gains immediately, since
we have a fair number of 'distinct' `DILocation`s being linked in.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243883 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 17:09:38 +00:00

297 lines
9.9 KiB
C++

//===- llvm/unittest/Linker/LinkModulesTest.cpp - IRBuilder tests ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/STLExtras.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/Linker/Linker.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm-c/Linker.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace {
class LinkModuleTest : public testing::Test {
protected:
void SetUp() override {
M.reset(new Module("MyModule", Ctx));
FunctionType *FTy = FunctionType::get(
Type::getInt8PtrTy(Ctx), Type::getInt32Ty(Ctx), false /*=isVarArg*/);
F = Function::Create(FTy, Function::ExternalLinkage, "ba_func", M.get());
F->setCallingConv(CallingConv::C);
EntryBB = BasicBlock::Create(Ctx, "entry", F);
SwitchCase1BB = BasicBlock::Create(Ctx, "switch.case.1", F);
SwitchCase2BB = BasicBlock::Create(Ctx, "switch.case.2", F);
ExitBB = BasicBlock::Create(Ctx, "exit", F);
AT = ArrayType::get(Type::getInt8PtrTy(Ctx), 3);
GV = new GlobalVariable(*M.get(), AT, false /*=isConstant*/,
GlobalValue::InternalLinkage, nullptr,"switch.bas");
// Global Initializer
std::vector<Constant *> Init;
Constant *SwitchCase1BA = BlockAddress::get(SwitchCase1BB);
Init.push_back(SwitchCase1BA);
Constant *SwitchCase2BA = BlockAddress::get(SwitchCase2BB);
Init.push_back(SwitchCase2BA);
ConstantInt *One = ConstantInt::get(Type::getInt32Ty(Ctx), 1);
Constant *OnePtr = ConstantExpr::getCast(Instruction::IntToPtr, One,
Type::getInt8PtrTy(Ctx));
Init.push_back(OnePtr);
GV->setInitializer(ConstantArray::get(AT, Init));
}
void TearDown() override { M.reset(); }
LLVMContext Ctx;
std::unique_ptr<Module> M;
Function *F;
ArrayType *AT;
GlobalVariable *GV;
BasicBlock *EntryBB;
BasicBlock *SwitchCase1BB;
BasicBlock *SwitchCase2BB;
BasicBlock *ExitBB;
};
TEST_F(LinkModuleTest, BlockAddress) {
IRBuilder<> Builder(EntryBB);
std::vector<Value *> GEPIndices;
GEPIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ctx), 0));
GEPIndices.push_back(F->arg_begin());
Value *GEP = Builder.CreateGEP(AT, GV, GEPIndices, "switch.gep");
Value *Load = Builder.CreateLoad(GEP, "switch.load");
Builder.CreateRet(Load);
Builder.SetInsertPoint(SwitchCase1BB);
Builder.CreateBr(ExitBB);
Builder.SetInsertPoint(SwitchCase2BB);
Builder.CreateBr(ExitBB);
Builder.SetInsertPoint(ExitBB);
Builder.CreateRet(ConstantPointerNull::get(Type::getInt8PtrTy(Ctx)));
Module *LinkedModule = new Module("MyModuleLinked", Ctx);
Linker::LinkModules(LinkedModule, M.get());
// Delete the original module.
M.reset();
// Check that the global "@switch.bas" is well-formed.
const GlobalVariable *LinkedGV = LinkedModule->getNamedGlobal("switch.bas");
const Constant *Init = LinkedGV->getInitializer();
// @switch.bas = internal global [3 x i8*]
// [i8* blockaddress(@ba_func, %switch.case.1),
// i8* blockaddress(@ba_func, %switch.case.2),
// i8* inttoptr (i32 1 to i8*)]
ArrayType *AT = ArrayType::get(Type::getInt8PtrTy(Ctx), 3);
EXPECT_EQ(AT, Init->getType());
Value *Elem = Init->getOperand(0);
ASSERT_TRUE(isa<BlockAddress>(Elem));
EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
LinkedModule->getFunction("ba_func"));
EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
LinkedModule->getFunction("ba_func"));
Elem = Init->getOperand(1);
ASSERT_TRUE(isa<BlockAddress>(Elem));
EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
LinkedModule->getFunction("ba_func"));
EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
LinkedModule->getFunction("ba_func"));
delete LinkedModule;
}
static Module *getExternal(LLVMContext &Ctx, StringRef FuncName) {
// Create a module with an empty externally-linked function
Module *M = new Module("ExternalModule", Ctx);
FunctionType *FTy = FunctionType::get(
Type::getVoidTy(Ctx), Type::getInt8PtrTy(Ctx), false /*=isVarArgs*/);
Function *F =
Function::Create(FTy, Function::ExternalLinkage, FuncName, M);
F->setCallingConv(CallingConv::C);
BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
IRBuilder<> Builder(BB);
Builder.CreateRetVoid();
return M;
}
static Module *getInternal(LLVMContext &Ctx) {
Module *InternalM = new Module("InternalModule", Ctx);
FunctionType *FTy = FunctionType::get(
Type::getVoidTy(Ctx), Type::getInt8PtrTy(Ctx), false /*=isVarArgs*/);
Function *F =
Function::Create(FTy, Function::InternalLinkage, "bar", InternalM);
F->setCallingConv(CallingConv::C);
BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
IRBuilder<> Builder(BB);
Builder.CreateRetVoid();
StructType *STy = StructType::create(Ctx, PointerType::get(FTy, 0));
GlobalVariable *GV =
new GlobalVariable(*InternalM, STy, false /*=isConstant*/,
GlobalValue::InternalLinkage, nullptr, "g");
GV->setInitializer(ConstantStruct::get(STy, F));
return InternalM;
}
TEST_F(LinkModuleTest, EmptyModule) {
std::unique_ptr<Module> InternalM(getInternal(Ctx));
std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
Linker::LinkModules(EmptyM.get(), InternalM.get());
}
TEST_F(LinkModuleTest, EmptyModule2) {
std::unique_ptr<Module> InternalM(getInternal(Ctx));
std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
Linker::LinkModules(InternalM.get(), EmptyM.get());
}
TEST_F(LinkModuleTest, TypeMerge) {
LLVMContext C;
SMDiagnostic Err;
const char *M1Str = "%t = type {i32}\n"
"@t1 = weak global %t zeroinitializer\n";
std::unique_ptr<Module> M1 = parseAssemblyString(M1Str, Err, C);
const char *M2Str = "%t = type {i32}\n"
"@t2 = weak global %t zeroinitializer\n";
std::unique_ptr<Module> M2 = parseAssemblyString(M2Str, Err, C);
Linker::LinkModules(M1.get(), M2.get(), [](const llvm::DiagnosticInfo &){});
EXPECT_EQ(M1->getNamedGlobal("t1")->getType(),
M1->getNamedGlobal("t2")->getType());
}
TEST_F(LinkModuleTest, CAPISuccess) {
std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
std::unique_ptr<Module> SourceM(getExternal(Ctx, "bar"));
char *errout = nullptr;
LLVMBool result = LLVMLinkModules(wrap(DestM.get()), wrap(SourceM.get()),
LLVMLinkerDestroySource, &errout);
EXPECT_EQ(0, result);
EXPECT_EQ(nullptr, errout);
// "bar" is present in destination module
EXPECT_NE(nullptr, DestM->getFunction("bar"));
}
TEST_F(LinkModuleTest, CAPIFailure) {
// Symbol clash between two modules
std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
std::unique_ptr<Module> SourceM(getExternal(Ctx, "foo"));
char *errout = nullptr;
LLVMBool result = LLVMLinkModules(wrap(DestM.get()), wrap(SourceM.get()),
LLVMLinkerDestroySource, &errout);
EXPECT_EQ(1, result);
EXPECT_STREQ("Linking globals named 'foo': symbol multiply defined!", errout);
LLVMDisposeMessage(errout);
}
TEST_F(LinkModuleTest, MoveDistinctMDs) {
LLVMContext C;
SMDiagnostic Err;
const char *SrcStr = "define void @foo() !attach !0 {\n"
"entry:\n"
" call void @llvm.md(metadata !1)\n"
" ret void, !attach !2\n"
"}\n"
"declare void @llvm.md(metadata)\n"
"!named = !{!3, !4}\n"
"!0 = distinct !{}\n"
"!1 = distinct !{}\n"
"!2 = distinct !{}\n"
"!3 = distinct !{}\n"
"!4 = !{!3}\n";
std::unique_ptr<Module> Src = parseAssemblyString(SrcStr, Err, C);
assert(Src);
ASSERT_TRUE(Src.get());
// Get the addresses of the Metadata before merging.
Function *F = &*Src->begin();
ASSERT_EQ("foo", F->getName());
BasicBlock *BB = &F->getEntryBlock();
auto *CI = cast<CallInst>(&BB->front());
auto *RI = cast<ReturnInst>(BB->getTerminator());
NamedMDNode *NMD = &*Src->named_metadata_begin();
MDNode *M0 = F->getMetadata("attach");
MDNode *M1 =
cast<MDNode>(cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
MDNode *M2 = RI->getMetadata("attach");
MDNode *M3 = NMD->getOperand(0);
MDNode *M4 = NMD->getOperand(1);
// Confirm a few things about the IR.
EXPECT_TRUE(M0->isDistinct());
EXPECT_TRUE(M1->isDistinct());
EXPECT_TRUE(M2->isDistinct());
EXPECT_TRUE(M3->isDistinct());
EXPECT_TRUE(M4->isUniqued());
EXPECT_EQ(M3, M4->getOperand(0));
// Link into destination module.
auto Dst = llvm::make_unique<Module>("Linked", C);
ASSERT_TRUE(Dst.get());
Linker::LinkModules(Dst.get(), Src.get(),
[](const llvm::DiagnosticInfo &) {});
// Check that distinct metadata was moved, not cloned. Even !4, the uniqued
// node, should effectively be moved, since its only operand hasn't changed.
F = &*Dst->begin();
BB = &F->getEntryBlock();
CI = cast<CallInst>(&BB->front());
RI = cast<ReturnInst>(BB->getTerminator());
NMD = &*Dst->named_metadata_begin();
EXPECT_EQ(M0, F->getMetadata("attach"));
EXPECT_EQ(M1, cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
EXPECT_EQ(M2, RI->getMetadata("attach"));
EXPECT_EQ(M3, NMD->getOperand(0));
EXPECT_EQ(M4, NMD->getOperand(1));
// Confirm a few things about the IR. This shouldn't have changed.
EXPECT_TRUE(M0->isDistinct());
EXPECT_TRUE(M1->isDistinct());
EXPECT_TRUE(M2->isDistinct());
EXPECT_TRUE(M3->isDistinct());
EXPECT_TRUE(M4->isUniqued());
EXPECT_EQ(M3, M4->getOperand(0));
}
} // end anonymous namespace