xref: /llvm-project/llvm/unittests/Linker/LinkModulesTest.cpp (revision 739c86df807748182e576e11697db6002738aafd) 
1 //===- llvm/unittest/Linker/LinkModulesTest.cpp - IRBuilder tests ---------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm-c/Core.h"
10 #include "llvm-c/Linker.h"
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/AsmParser/Parser.h"
13 #include "llvm/IR/BasicBlock.h"
14 #include "llvm/IR/DataLayout.h"
15 #include "llvm/IR/Function.h"
16 #include "llvm/IR/IRBuilder.h"
17 #include "llvm/IR/Module.h"
18 #include "llvm/Linker/Linker.h"
19 #include "llvm/Support/SourceMgr.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::getIntToPtr(One, Type::getInt8PtrTy(Ctx));
55     Init.push_back(OnePtr);
56 
57     GV->setInitializer(ConstantArray::get(AT, Init));
58   }
59 
60   void TearDown() override { M.reset(); }
61 
62   LLVMContext Ctx;
63   std::unique_ptr<Module> M;
64   Function *F;
65   ArrayType *AT;
66   GlobalVariable *GV;
67   BasicBlock *EntryBB;
68   BasicBlock *SwitchCase1BB;
69   BasicBlock *SwitchCase2BB;
70   BasicBlock *ExitBB;
71 };
72 
73 static void expectNoDiags(const DiagnosticInfo &DI, void *C) {
74   llvm_unreachable("expectNoDiags called!");
75 }
76 
77 TEST_F(LinkModuleTest, BlockAddress) {
78   IRBuilder<> Builder(EntryBB);
79 
80   std::vector<Value *> GEPIndices;
81   GEPIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ctx), 0));
82   GEPIndices.push_back(&*F->arg_begin());
83 
84   Value *GEP = Builder.CreateGEP(AT, GV, GEPIndices, "switch.gep");
85   Value *Load = Builder.CreateLoad(AT->getElementType(), GEP, "switch.load");
86 
87   Builder.CreateRet(Load);
88 
89   Builder.SetInsertPoint(SwitchCase1BB);
90   Builder.CreateBr(ExitBB);
91 
92   Builder.SetInsertPoint(SwitchCase2BB);
93   Builder.CreateBr(ExitBB);
94 
95   Builder.SetInsertPoint(ExitBB);
96   Builder.CreateRet(ConstantPointerNull::get(Type::getInt8PtrTy(Ctx)));
97 
98   Module *LinkedModule = new Module("MyModuleLinked", Ctx);
99   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
100   Linker::linkModules(*LinkedModule, std::move(M));
101 
102   // Check that the global "@switch.bas" is well-formed.
103   const GlobalVariable *LinkedGV = LinkedModule->getNamedGlobal("switch.bas");
104   const Constant *Init = LinkedGV->getInitializer();
105 
106   // @switch.bas = internal global [3 x i8*]
107   //   [i8* blockaddress(@ba_func, %switch.case.1),
108   //    i8* blockaddress(@ba_func, %switch.case.2),
109   //    i8* inttoptr (i32 1 to i8*)]
110 
111   ArrayType *AT = ArrayType::get(Type::getInt8PtrTy(Ctx), 3);
112   EXPECT_EQ(AT, Init->getType());
113 
114   Value *Elem = Init->getOperand(0);
115   ASSERT_TRUE(isa<BlockAddress>(Elem));
116   EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
117             LinkedModule->getFunction("ba_func"));
118   EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
119             LinkedModule->getFunction("ba_func"));
120 
121   Elem = Init->getOperand(1);
122   ASSERT_TRUE(isa<BlockAddress>(Elem));
123   EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
124             LinkedModule->getFunction("ba_func"));
125   EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
126             LinkedModule->getFunction("ba_func"));
127 
128   delete LinkedModule;
129 }
130 
131 static Module *getExternal(LLVMContext &Ctx, StringRef FuncName) {
132   // Create a module with an empty externally-linked function
133   Module *M = new Module("ExternalModule", Ctx);
134   FunctionType *FTy = FunctionType::get(
135       Type::getVoidTy(Ctx), Type::getInt8PtrTy(Ctx), false /*=isVarArgs*/);
136 
137   Function *F =
138       Function::Create(FTy, Function::ExternalLinkage, FuncName, M);
139   F->setCallingConv(CallingConv::C);
140 
141   BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
142   IRBuilder<> Builder(BB);
143   Builder.CreateRetVoid();
144   return M;
145 }
146 
147 static Module *getInternal(LLVMContext &Ctx) {
148   Module *InternalM = new Module("InternalModule", Ctx);
149   FunctionType *FTy = FunctionType::get(
150       Type::getVoidTy(Ctx), Type::getInt8PtrTy(Ctx), false /*=isVarArgs*/);
151 
152   Function *F =
153       Function::Create(FTy, Function::InternalLinkage, "bar", InternalM);
154   F->setCallingConv(CallingConv::C);
155 
156   BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
157   IRBuilder<> Builder(BB);
158   Builder.CreateRetVoid();
159 
160   StructType *STy = StructType::create(Ctx, PointerType::get(FTy, 0));
161 
162   GlobalVariable *GV =
163       new GlobalVariable(*InternalM, STy, false /*=isConstant*/,
164                          GlobalValue::InternalLinkage, nullptr, "g");
165 
166   GV->setInitializer(ConstantStruct::get(STy, F));
167   return InternalM;
168 }
169 
170 TEST_F(LinkModuleTest, EmptyModule) {
171   std::unique_ptr<Module> InternalM(getInternal(Ctx));
172   std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
173   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
174   Linker::linkModules(*EmptyM, std::move(InternalM));
175 }
176 
177 TEST_F(LinkModuleTest, EmptyModule2) {
178   std::unique_ptr<Module> InternalM(getInternal(Ctx));
179   std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
180   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
181   Linker::linkModules(*InternalM, std::move(EmptyM));
182 }
183 
184 TEST_F(LinkModuleTest, TypeMerge) {
185   LLVMContext C;
186   SMDiagnostic Err;
187 
188   const char *M1Str = "%t = type {i32}\n"
189                       "@t1 = weak global %t zeroinitializer\n";
190   std::unique_ptr<Module> M1 = parseAssemblyString(M1Str, Err, C);
191 
192   const char *M2Str = "%t = type {i32}\n"
193                       "@t2 = weak global %t zeroinitializer\n";
194   std::unique_ptr<Module> M2 = parseAssemblyString(M2Str, Err, C);
195 
196   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
197   Linker::linkModules(*M1, std::move(M2));
198 
199   EXPECT_EQ(M1->getNamedGlobal("t1")->getType(),
200             M1->getNamedGlobal("t2")->getType());
201 }
202 
203 TEST_F(LinkModuleTest, NewCAPISuccess) {
204   std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
205   std::unique_ptr<Module> SourceM(getExternal(Ctx, "bar"));
206   LLVMBool Result =
207       LLVMLinkModules2(wrap(DestM.get()), wrap(SourceM.release()));
208   EXPECT_EQ(0, Result);
209   // "bar" is present in destination module
210   EXPECT_NE(nullptr, DestM->getFunction("bar"));
211 }
212 
213 static void diagnosticHandler(LLVMDiagnosticInfoRef DI, void *C) {
214   auto *Err = reinterpret_cast<std::string *>(C);
215   char *CErr = LLVMGetDiagInfoDescription(DI);
216   *Err = CErr;
217   LLVMDisposeMessage(CErr);
218 }
219 
220 TEST_F(LinkModuleTest, NewCAPIFailure) {
221   // Symbol clash between two modules
222   LLVMContext Ctx;
223   std::string Err;
224   LLVMContextSetDiagnosticHandler(wrap(&Ctx), diagnosticHandler, &Err);
225 
226   std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
227   std::unique_ptr<Module> SourceM(getExternal(Ctx, "foo"));
228   LLVMBool Result =
229       LLVMLinkModules2(wrap(DestM.get()), wrap(SourceM.release()));
230   EXPECT_EQ(1, Result);
231   EXPECT_EQ("Linking globals named 'foo': symbol multiply defined!", Err);
232 }
233 
234 TEST_F(LinkModuleTest, MoveDistinctMDs) {
235   LLVMContext C;
236   SMDiagnostic Err;
237 
238   const char *SrcStr = "define void @foo() !attach !0 {\n"
239                        "entry:\n"
240                        "  call void @llvm.md(metadata !1)\n"
241                        "  ret void, !attach !2\n"
242                        "}\n"
243                        "declare void @llvm.md(metadata)\n"
244                        "!named = !{!3, !4}\n"
245                        "!0 = distinct !{}\n"
246                        "!1 = distinct !{}\n"
247                        "!2 = distinct !{}\n"
248                        "!3 = distinct !{}\n"
249                        "!4 = !{!3}\n";
250 
251   std::unique_ptr<Module> Src = parseAssemblyString(SrcStr, Err, C);
252   assert(Src);
253   ASSERT_TRUE(Src.get());
254 
255   // Get the addresses of the Metadata before merging.
256   Function *F = &*Src->begin();
257   ASSERT_EQ("foo", F->getName());
258   BasicBlock *BB = &F->getEntryBlock();
259   auto *CI = cast<CallInst>(&BB->front());
260   auto *RI = cast<ReturnInst>(BB->getTerminator());
261   NamedMDNode *NMD = &*Src->named_metadata_begin();
262 
263   MDNode *M0 = F->getMetadata("attach");
264   MDNode *M1 =
265       cast<MDNode>(cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
266   MDNode *M2 = RI->getMetadata("attach");
267   MDNode *M3 = NMD->getOperand(0);
268   MDNode *M4 = NMD->getOperand(1);
269 
270   // Confirm a few things about the IR.
271   EXPECT_TRUE(M0->isDistinct());
272   EXPECT_TRUE(M1->isDistinct());
273   EXPECT_TRUE(M2->isDistinct());
274   EXPECT_TRUE(M3->isDistinct());
275   EXPECT_TRUE(M4->isUniqued());
276   EXPECT_EQ(M3, M4->getOperand(0));
277 
278   // Link into destination module.
279   auto Dst = std::make_unique<Module>("Linked", C);
280   ASSERT_TRUE(Dst.get());
281   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
282   Linker::linkModules(*Dst, std::move(Src));
283 
284   // Check that distinct metadata was moved, not cloned.  Even !4, the uniqued
285   // node, should effectively be moved, since its only operand hasn't changed.
286   F = &*Dst->begin();
287   BB = &F->getEntryBlock();
288   CI = cast<CallInst>(&BB->front());
289   RI = cast<ReturnInst>(BB->getTerminator());
290   NMD = &*Dst->named_metadata_begin();
291 
292   EXPECT_EQ(M0, F->getMetadata("attach"));
293   EXPECT_EQ(M1, cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
294   EXPECT_EQ(M2, RI->getMetadata("attach"));
295   EXPECT_EQ(M3, NMD->getOperand(0));
296   EXPECT_EQ(M4, NMD->getOperand(1));
297 
298   // Confirm a few things about the IR.  This shouldn't have changed.
299   EXPECT_TRUE(M0->isDistinct());
300   EXPECT_TRUE(M1->isDistinct());
301   EXPECT_TRUE(M2->isDistinct());
302   EXPECT_TRUE(M3->isDistinct());
303   EXPECT_TRUE(M4->isUniqued());
304   EXPECT_EQ(M3, M4->getOperand(0));
305 }
306 
307 TEST_F(LinkModuleTest, RemangleIntrinsics) {
308   LLVMContext C;
309   SMDiagnostic Err;
310 
311   // We load two modules inside the same context C. In both modules there is a
312   // "struct.rtx_def" type. In the module loaded the second (Bar) this type will
313   // be renamed to "struct.rtx_def.0". Check that the intrinsics which have this
314   // type in the signature are properly remangled.
315   const char *FooStr =
316     "%struct.rtx_def = type { i16 }\n"
317     "define void @foo(%struct.rtx_def %a) {\n"
318     "  call %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def %a)\n"
319     "  ret void\n"
320     "}\n"
321     "declare %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def)\n";
322 
323   const char *BarStr =
324     "%struct.rtx_def = type { i16 }\n"
325     "define void @bar(%struct.rtx_def %a) {\n"
326     "  call %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def %a)\n"
327     "  ret void\n"
328     "}\n"
329     "declare %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def)\n";
330 
331   std::unique_ptr<Module> Foo = parseAssemblyString(FooStr, Err, C);
332   assert(Foo);
333   ASSERT_TRUE(Foo.get());
334   // Foo is loaded first, so the type and the intrinsic have theis original
335   // names.
336   ASSERT_TRUE(Foo->getFunction("llvm.ssa.copy.s_struct.rtx_defs"));
337   ASSERT_FALSE(Foo->getFunction("llvm.ssa.copy.s_struct.rtx_defs.0"));
338 
339   std::unique_ptr<Module> Bar = parseAssemblyString(BarStr, Err, C);
340   assert(Bar);
341   ASSERT_TRUE(Bar.get());
342   // Bar is loaded after Foo, so the type is renamed to struct.rtx_def.0. Check
343   // that the intrinsic is also renamed.
344   ASSERT_FALSE(Bar->getFunction("llvm.ssa.copy.s_struct.rtx_defs"));
345   ASSERT_TRUE(Bar->getFunction("llvm.ssa.copy.s_struct.rtx_def.0s"));
346 
347   // Link two modules together.
348   auto Dst = std::make_unique<Module>("Linked", C);
349   ASSERT_TRUE(Dst.get());
350   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
351   bool Failed = Linker::linkModules(*Foo, std::move(Bar));
352   ASSERT_FALSE(Failed);
353 
354   // "struct.rtx_def" from Foo and "struct.rtx_def.0" from Bar are isomorphic
355   // types, so they must be uniquified by linker. Check that they use the same
356   // intrinsic definition.
357   Function *F = Foo->getFunction("llvm.ssa.copy.s_struct.rtx_defs");
358   ASSERT_EQ(F->getNumUses(), (unsigned)2);
359 }
360 
361 } // end anonymous namespace
362