xref: /llvm-project/llvm/unittests/Linker/LinkModulesTest.cpp (revision c8925b18719f5ee2da586a3f41b3e143c5d3466a) 
1 //===- llvm/unittest/Linker/LinkModulesTest.cpp - IRBuilder tests ---------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/ADT/STLExtras.h"
11 #include "llvm/AsmParser/Parser.h"
12 #include "llvm/IR/BasicBlock.h"
13 #include "llvm/IR/DataLayout.h"
14 #include "llvm/IR/Function.h"
15 #include "llvm/IR/IRBuilder.h"
16 #include "llvm/IR/Module.h"
17 #include "llvm/Linker/Linker.h"
18 #include "llvm/Support/SourceMgr.h"
19 #include "llvm-c/Linker.h"
20 #include "gtest/gtest.h"
21 
22 using namespace llvm;
23 
24 namespace {
25 
26 class LinkModuleTest : public testing::Test {
27 protected:
28   void SetUp() override {
29     M.reset(new Module("MyModule", Ctx));
30     FunctionType *FTy = FunctionType::get(
31         Type::getInt8PtrTy(Ctx), Type::getInt32Ty(Ctx), false /*=isVarArg*/);
32     F = Function::Create(FTy, Function::ExternalLinkage, "ba_func", M.get());
33     F->setCallingConv(CallingConv::C);
34 
35     EntryBB = BasicBlock::Create(Ctx, "entry", F);
36     SwitchCase1BB = BasicBlock::Create(Ctx, "switch.case.1", F);
37     SwitchCase2BB = BasicBlock::Create(Ctx, "switch.case.2", F);
38     ExitBB = BasicBlock::Create(Ctx, "exit", F);
39 
40     AT = ArrayType::get(Type::getInt8PtrTy(Ctx), 3);
41 
42     GV = new GlobalVariable(*M.get(), AT, false /*=isConstant*/,
43                             GlobalValue::InternalLinkage, nullptr,"switch.bas");
44 
45     // Global Initializer
46     std::vector<Constant *> Init;
47     Constant *SwitchCase1BA = BlockAddress::get(SwitchCase1BB);
48     Init.push_back(SwitchCase1BA);
49 
50     Constant *SwitchCase2BA = BlockAddress::get(SwitchCase2BB);
51     Init.push_back(SwitchCase2BA);
52 
53     ConstantInt *One = ConstantInt::get(Type::getInt32Ty(Ctx), 1);
54     Constant *OnePtr = ConstantExpr::getCast(Instruction::IntToPtr, One,
55                                              Type::getInt8PtrTy(Ctx));
56     Init.push_back(OnePtr);
57 
58     GV->setInitializer(ConstantArray::get(AT, Init));
59   }
60 
61   void TearDown() override { M.reset(); }
62 
63   LLVMContext Ctx;
64   std::unique_ptr<Module> M;
65   Function *F;
66   ArrayType *AT;
67   GlobalVariable *GV;
68   BasicBlock *EntryBB;
69   BasicBlock *SwitchCase1BB;
70   BasicBlock *SwitchCase2BB;
71   BasicBlock *ExitBB;
72 };
73 
74 TEST_F(LinkModuleTest, BlockAddress) {
75   IRBuilder<> Builder(EntryBB);
76 
77   std::vector<Value *> GEPIndices;
78   GEPIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ctx), 0));
79   GEPIndices.push_back(&*F->arg_begin());
80 
81   Value *GEP = Builder.CreateGEP(AT, GV, GEPIndices, "switch.gep");
82   Value *Load = Builder.CreateLoad(GEP, "switch.load");
83 
84   Builder.CreateRet(Load);
85 
86   Builder.SetInsertPoint(SwitchCase1BB);
87   Builder.CreateBr(ExitBB);
88 
89   Builder.SetInsertPoint(SwitchCase2BB);
90   Builder.CreateBr(ExitBB);
91 
92   Builder.SetInsertPoint(ExitBB);
93   Builder.CreateRet(ConstantPointerNull::get(Type::getInt8PtrTy(Ctx)));
94 
95   Module *LinkedModule = new Module("MyModuleLinked", Ctx);
96   Linker::LinkModules(LinkedModule, M.get());
97 
98   // Delete the original module.
99   M.reset();
100 
101   // Check that the global "@switch.bas" is well-formed.
102   const GlobalVariable *LinkedGV = LinkedModule->getNamedGlobal("switch.bas");
103   const Constant *Init = LinkedGV->getInitializer();
104 
105   // @switch.bas = internal global [3 x i8*]
106   //   [i8* blockaddress(@ba_func, %switch.case.1),
107   //    i8* blockaddress(@ba_func, %switch.case.2),
108   //    i8* inttoptr (i32 1 to i8*)]
109 
110   ArrayType *AT = ArrayType::get(Type::getInt8PtrTy(Ctx), 3);
111   EXPECT_EQ(AT, Init->getType());
112 
113   Value *Elem = Init->getOperand(0);
114   ASSERT_TRUE(isa<BlockAddress>(Elem));
115   EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
116             LinkedModule->getFunction("ba_func"));
117   EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
118             LinkedModule->getFunction("ba_func"));
119 
120   Elem = Init->getOperand(1);
121   ASSERT_TRUE(isa<BlockAddress>(Elem));
122   EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
123             LinkedModule->getFunction("ba_func"));
124   EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
125             LinkedModule->getFunction("ba_func"));
126 
127   delete LinkedModule;
128 }
129 
130 static Module *getExternal(LLVMContext &Ctx, StringRef FuncName) {
131   // Create a module with an empty externally-linked function
132   Module *M = new Module("ExternalModule", Ctx);
133   FunctionType *FTy = FunctionType::get(
134       Type::getVoidTy(Ctx), Type::getInt8PtrTy(Ctx), false /*=isVarArgs*/);
135 
136   Function *F =
137       Function::Create(FTy, Function::ExternalLinkage, FuncName, M);
138   F->setCallingConv(CallingConv::C);
139 
140   BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
141   IRBuilder<> Builder(BB);
142   Builder.CreateRetVoid();
143   return M;
144 }
145 
146 static Module *getInternal(LLVMContext &Ctx) {
147   Module *InternalM = new Module("InternalModule", Ctx);
148   FunctionType *FTy = FunctionType::get(
149       Type::getVoidTy(Ctx), Type::getInt8PtrTy(Ctx), false /*=isVarArgs*/);
150 
151   Function *F =
152       Function::Create(FTy, Function::InternalLinkage, "bar", InternalM);
153   F->setCallingConv(CallingConv::C);
154 
155   BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
156   IRBuilder<> Builder(BB);
157   Builder.CreateRetVoid();
158 
159   StructType *STy = StructType::create(Ctx, PointerType::get(FTy, 0));
160 
161   GlobalVariable *GV =
162       new GlobalVariable(*InternalM, STy, false /*=isConstant*/,
163                          GlobalValue::InternalLinkage, nullptr, "g");
164 
165   GV->setInitializer(ConstantStruct::get(STy, F));
166   return InternalM;
167 }
168 
169 TEST_F(LinkModuleTest, EmptyModule) {
170   std::unique_ptr<Module> InternalM(getInternal(Ctx));
171   std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
172   Linker::LinkModules(EmptyM.get(), InternalM.get());
173 }
174 
175 TEST_F(LinkModuleTest, EmptyModule2) {
176   std::unique_ptr<Module> InternalM(getInternal(Ctx));
177   std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
178   Linker::LinkModules(InternalM.get(), EmptyM.get());
179 }
180 
181 TEST_F(LinkModuleTest, TypeMerge) {
182   LLVMContext C;
183   SMDiagnostic Err;
184 
185   const char *M1Str = "%t = type {i32}\n"
186                       "@t1 = weak global %t zeroinitializer\n";
187   std::unique_ptr<Module> M1 = parseAssemblyString(M1Str, Err, C);
188 
189   const char *M2Str = "%t = type {i32}\n"
190                       "@t2 = weak global %t zeroinitializer\n";
191   std::unique_ptr<Module> M2 = parseAssemblyString(M2Str, Err, C);
192 
193   Linker::LinkModules(M1.get(), M2.get(), [](const llvm::DiagnosticInfo &){});
194 
195   EXPECT_EQ(M1->getNamedGlobal("t1")->getType(),
196             M1->getNamedGlobal("t2")->getType());
197 }
198 
199 TEST_F(LinkModuleTest, CAPISuccess) {
200   std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
201   std::unique_ptr<Module> SourceM(getExternal(Ctx, "bar"));
202   char *errout = nullptr;
203   LLVMBool result = LLVMLinkModules(wrap(DestM.get()), wrap(SourceM.get()),
204                                     LLVMLinkerDestroySource, &errout);
205   EXPECT_EQ(0, result);
206   EXPECT_EQ(nullptr, errout);
207   // "bar" is present in destination module
208   EXPECT_NE(nullptr, DestM->getFunction("bar"));
209 }
210 
211 TEST_F(LinkModuleTest, CAPIFailure) {
212   // Symbol clash between two modules
213   std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
214   std::unique_ptr<Module> SourceM(getExternal(Ctx, "foo"));
215   char *errout = nullptr;
216   LLVMBool result = LLVMLinkModules(wrap(DestM.get()), wrap(SourceM.get()),
217                                     LLVMLinkerDestroySource, &errout);
218   EXPECT_EQ(1, result);
219   EXPECT_STREQ("Linking globals named 'foo': symbol multiply defined!", errout);
220   LLVMDisposeMessage(errout);
221 }
222 
223 TEST_F(LinkModuleTest, MoveDistinctMDs) {
224   LLVMContext C;
225   SMDiagnostic Err;
226 
227   const char *SrcStr = "define void @foo() !attach !0 {\n"
228                        "entry:\n"
229                        "  call void @llvm.md(metadata !1)\n"
230                        "  ret void, !attach !2\n"
231                        "}\n"
232                        "declare void @llvm.md(metadata)\n"
233                        "!named = !{!3, !4}\n"
234                        "!0 = distinct !{}\n"
235                        "!1 = distinct !{}\n"
236                        "!2 = distinct !{}\n"
237                        "!3 = distinct !{}\n"
238                        "!4 = !{!3}\n";
239 
240   std::unique_ptr<Module> Src = parseAssemblyString(SrcStr, Err, C);
241   assert(Src);
242   ASSERT_TRUE(Src.get());
243 
244   // Get the addresses of the Metadata before merging.
245   Function *F = &*Src->begin();
246   ASSERT_EQ("foo", F->getName());
247   BasicBlock *BB = &F->getEntryBlock();
248   auto *CI = cast<CallInst>(&BB->front());
249   auto *RI = cast<ReturnInst>(BB->getTerminator());
250   NamedMDNode *NMD = &*Src->named_metadata_begin();
251 
252   MDNode *M0 = F->getMetadata("attach");
253   MDNode *M1 =
254       cast<MDNode>(cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
255   MDNode *M2 = RI->getMetadata("attach");
256   MDNode *M3 = NMD->getOperand(0);
257   MDNode *M4 = NMD->getOperand(1);
258 
259   // Confirm a few things about the IR.
260   EXPECT_TRUE(M0->isDistinct());
261   EXPECT_TRUE(M1->isDistinct());
262   EXPECT_TRUE(M2->isDistinct());
263   EXPECT_TRUE(M3->isDistinct());
264   EXPECT_TRUE(M4->isUniqued());
265   EXPECT_EQ(M3, M4->getOperand(0));
266 
267   // Link into destination module.
268   auto Dst = llvm::make_unique<Module>("Linked", C);
269   ASSERT_TRUE(Dst.get());
270   Linker::LinkModules(Dst.get(), Src.get(),
271                       [](const llvm::DiagnosticInfo &) {});
272 
273   // Check that distinct metadata was moved, not cloned.  Even !4, the uniqued
274   // node, should effectively be moved, since its only operand hasn't changed.
275   F = &*Dst->begin();
276   BB = &F->getEntryBlock();
277   CI = cast<CallInst>(&BB->front());
278   RI = cast<ReturnInst>(BB->getTerminator());
279   NMD = &*Dst->named_metadata_begin();
280 
281   EXPECT_EQ(M0, F->getMetadata("attach"));
282   EXPECT_EQ(M1, cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
283   EXPECT_EQ(M2, RI->getMetadata("attach"));
284   EXPECT_EQ(M3, NMD->getOperand(0));
285   EXPECT_EQ(M4, NMD->getOperand(1));
286 
287   // Confirm a few things about the IR.  This shouldn't have changed.
288   EXPECT_TRUE(M0->isDistinct());
289   EXPECT_TRUE(M1->isDistinct());
290   EXPECT_TRUE(M2->isDistinct());
291   EXPECT_TRUE(M3->isDistinct());
292   EXPECT_TRUE(M4->isUniqued());
293   EXPECT_EQ(M3, M4->getOperand(0));
294 }
295 
296 } // end anonymous namespace
297