xref: /llvm-project/llvm/unittests/Linker/LinkModulesTest.cpp (revision 97d691b4b3f5ba446d6827fc29fbe15e44a7adac) 
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 =
31         FunctionType::get(PointerType::getUnqual(Ctx), Type::getInt32Ty(Ctx),
32                           false /*=isVarArg*/);
33     F = Function::Create(FTy, Function::ExternalLinkage, "ba_func", M.get());
34     F->setCallingConv(CallingConv::C);
35 
36     EntryBB = BasicBlock::Create(Ctx, "entry", F);
37     SwitchCase1BB = BasicBlock::Create(Ctx, "switch.case.1", F);
38     SwitchCase2BB = BasicBlock::Create(Ctx, "switch.case.2", F);
39     ExitBB = BasicBlock::Create(Ctx, "exit", F);
40 
41     AT = ArrayType::get(PointerType::getUnqual(Ctx), 3);
42 
43     GV =
44         new GlobalVariable(*M, AT, false /*=isConstant*/,
45                            GlobalValue::InternalLinkage, nullptr, "switch.bas");
46 
47     // Global Initializer
48     std::vector<Constant *> Init;
49     Constant *SwitchCase1BA = BlockAddress::get(SwitchCase1BB);
50     Init.push_back(SwitchCase1BA);
51 
52     Constant *SwitchCase2BA = BlockAddress::get(SwitchCase2BB);
53     Init.push_back(SwitchCase2BA);
54 
55     ConstantInt *One = ConstantInt::get(Type::getInt32Ty(Ctx), 1);
56     Constant *OnePtr =
57         ConstantExpr::getIntToPtr(One, PointerType::getUnqual(Ctx));
58     Init.push_back(OnePtr);
59 
60     GV->setInitializer(ConstantArray::get(AT, Init));
61   }
62 
63   void TearDown() override { M.reset(); }
64 
65   LLVMContext Ctx;
66   std::unique_ptr<Module> M;
67   Function *F;
68   ArrayType *AT;
69   GlobalVariable *GV;
70   BasicBlock *EntryBB;
71   BasicBlock *SwitchCase1BB;
72   BasicBlock *SwitchCase2BB;
73   BasicBlock *ExitBB;
74 };
75 
76 static void expectNoDiags(const DiagnosticInfo *DI, void *C) {
77   llvm_unreachable("expectNoDiags called!");
78 }
79 
80 TEST_F(LinkModuleTest, BlockAddress) {
81   IRBuilder<> Builder(EntryBB);
82 
83   std::vector<Value *> GEPIndices;
84   GEPIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ctx), 0));
85   GEPIndices.push_back(&*F->arg_begin());
86 
87   Value *GEP = Builder.CreateGEP(AT, GV, GEPIndices, "switch.gep");
88   Value *Load = Builder.CreateLoad(AT->getElementType(), GEP, "switch.load");
89 
90   Builder.CreateRet(Load);
91 
92   Builder.SetInsertPoint(SwitchCase1BB);
93   Builder.CreateBr(ExitBB);
94 
95   Builder.SetInsertPoint(SwitchCase2BB);
96   Builder.CreateBr(ExitBB);
97 
98   Builder.SetInsertPoint(ExitBB);
99   Builder.CreateRet(ConstantPointerNull::get(PointerType::getUnqual(Ctx)));
100 
101   Module *LinkedModule = new Module("MyModuleLinked", Ctx);
102   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
103   Linker::linkModules(*LinkedModule, std::move(M));
104 
105   // Check that the global "@switch.bas" is well-formed.
106   const GlobalVariable *LinkedGV = LinkedModule->getNamedGlobal("switch.bas");
107   const Constant *Init = LinkedGV->getInitializer();
108 
109   // @switch.bas = internal global [3 x i8*]
110   //   [i8* blockaddress(@ba_func, %switch.case.1),
111   //    i8* blockaddress(@ba_func, %switch.case.2),
112   //    i8* inttoptr (i32 1 to i8*)]
113 
114   ArrayType *AT = ArrayType::get(PointerType::getUnqual(Ctx), 3);
115   EXPECT_EQ(AT, Init->getType());
116 
117   Value *Elem = Init->getOperand(0);
118   ASSERT_TRUE(isa<BlockAddress>(Elem));
119   EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
120             LinkedModule->getFunction("ba_func"));
121   EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
122             LinkedModule->getFunction("ba_func"));
123 
124   Elem = Init->getOperand(1);
125   ASSERT_TRUE(isa<BlockAddress>(Elem));
126   EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
127             LinkedModule->getFunction("ba_func"));
128   EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
129             LinkedModule->getFunction("ba_func"));
130 
131   delete LinkedModule;
132 }
133 
134 static Module *getExternal(LLVMContext &Ctx, StringRef FuncName) {
135   // Create a module with an empty externally-linked function
136   Module *M = new Module("ExternalModule", Ctx);
137   FunctionType *FTy = FunctionType::get(
138       Type::getVoidTy(Ctx), PointerType::getUnqual(Ctx), false /*=isVarArgs*/);
139 
140   Function *F =
141       Function::Create(FTy, Function::ExternalLinkage, FuncName, M);
142   F->setCallingConv(CallingConv::C);
143 
144   BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
145   IRBuilder<> Builder(BB);
146   Builder.CreateRetVoid();
147   return M;
148 }
149 
150 static Module *getInternal(LLVMContext &Ctx) {
151   Module *InternalM = new Module("InternalModule", Ctx);
152   FunctionType *FTy = FunctionType::get(
153       Type::getVoidTy(Ctx), PointerType::getUnqual(Ctx), false /*=isVarArgs*/);
154 
155   Function *F =
156       Function::Create(FTy, Function::InternalLinkage, "bar", InternalM);
157   F->setCallingConv(CallingConv::C);
158 
159   BasicBlock *BB = BasicBlock::Create(Ctx, "", F);
160   IRBuilder<> Builder(BB);
161   Builder.CreateRetVoid();
162 
163   StructType *STy = StructType::create(Ctx, PointerType::get(Ctx, 0));
164 
165   GlobalVariable *GV =
166       new GlobalVariable(*InternalM, STy, false /*=isConstant*/,
167                          GlobalValue::InternalLinkage, nullptr, "g");
168 
169   GV->setInitializer(ConstantStruct::get(STy, F));
170   return InternalM;
171 }
172 
173 TEST_F(LinkModuleTest, EmptyModule) {
174   std::unique_ptr<Module> InternalM(getInternal(Ctx));
175   std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
176   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
177   Linker::linkModules(*EmptyM, std::move(InternalM));
178 }
179 
180 TEST_F(LinkModuleTest, EmptyModule2) {
181   std::unique_ptr<Module> InternalM(getInternal(Ctx));
182   std::unique_ptr<Module> EmptyM(new Module("EmptyModule1", Ctx));
183   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
184   Linker::linkModules(*InternalM, std::move(EmptyM));
185 }
186 
187 TEST_F(LinkModuleTest, TypeMerge) {
188   LLVMContext C;
189   SMDiagnostic Err;
190 
191   const char *M1Str = "%t = type {i32}\n"
192                       "@t1 = weak global %t zeroinitializer\n";
193   std::unique_ptr<Module> M1 = parseAssemblyString(M1Str, Err, C);
194 
195   const char *M2Str = "%t = type {i32}\n"
196                       "@t2 = weak global %t zeroinitializer\n";
197   std::unique_ptr<Module> M2 = parseAssemblyString(M2Str, Err, C);
198 
199   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
200   Linker::linkModules(*M1, std::move(M2));
201 
202   EXPECT_EQ(M1->getNamedGlobal("t1")->getType(),
203             M1->getNamedGlobal("t2")->getType());
204 }
205 
206 TEST_F(LinkModuleTest, NewCAPISuccess) {
207   std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
208   std::unique_ptr<Module> SourceM(getExternal(Ctx, "bar"));
209   LLVMBool Result =
210       LLVMLinkModules2(wrap(DestM.get()), wrap(SourceM.release()));
211   EXPECT_EQ(0, Result);
212   // "bar" is present in destination module
213   EXPECT_NE(nullptr, DestM->getFunction("bar"));
214 }
215 
216 static void diagnosticHandler(LLVMDiagnosticInfoRef DI, void *C) {
217   auto *Err = reinterpret_cast<std::string *>(C);
218   char *CErr = LLVMGetDiagInfoDescription(DI);
219   *Err = CErr;
220   LLVMDisposeMessage(CErr);
221 }
222 
223 TEST_F(LinkModuleTest, NewCAPIFailure) {
224   // Symbol clash between two modules
225   LLVMContext Ctx;
226   std::string Err;
227   LLVMContextSetDiagnosticHandler(wrap(&Ctx), diagnosticHandler, &Err);
228 
229   std::unique_ptr<Module> DestM(getExternal(Ctx, "foo"));
230   std::unique_ptr<Module> SourceM(getExternal(Ctx, "foo"));
231   LLVMBool Result =
232       LLVMLinkModules2(wrap(DestM.get()), wrap(SourceM.release()));
233   EXPECT_EQ(1, Result);
234   EXPECT_EQ("Linking globals named 'foo': symbol multiply defined!", Err);
235 }
236 
237 TEST_F(LinkModuleTest, MoveDistinctMDs) {
238   LLVMContext C;
239   SMDiagnostic Err;
240 
241   const char *SrcStr = "define void @foo() !attach !0 {\n"
242                        "entry:\n"
243                        "  call void @llvm.md(metadata !1)\n"
244                        "  ret void, !attach !2\n"
245                        "}\n"
246                        "declare void @llvm.md(metadata)\n"
247                        "!named = !{!3, !4}\n"
248                        "!0 = distinct !{}\n"
249                        "!1 = distinct !{}\n"
250                        "!2 = distinct !{}\n"
251                        "!3 = distinct !{}\n"
252                        "!4 = !{!3}\n";
253 
254   std::unique_ptr<Module> Src = parseAssemblyString(SrcStr, Err, C);
255   assert(Src);
256   ASSERT_TRUE(Src.get());
257 
258   // Get the addresses of the Metadata before merging.
259   Function *F = &*Src->begin();
260   ASSERT_EQ("foo", F->getName());
261   BasicBlock *BB = &F->getEntryBlock();
262   auto *CI = cast<CallInst>(&BB->front());
263   auto *RI = cast<ReturnInst>(BB->getTerminator());
264   NamedMDNode *NMD = &*Src->named_metadata_begin();
265 
266   MDNode *M0 = F->getMetadata("attach");
267   MDNode *M1 =
268       cast<MDNode>(cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
269   MDNode *M2 = RI->getMetadata("attach");
270   MDNode *M3 = NMD->getOperand(0);
271   MDNode *M4 = NMD->getOperand(1);
272 
273   // Confirm a few things about the IR.
274   EXPECT_TRUE(M0->isDistinct());
275   EXPECT_TRUE(M1->isDistinct());
276   EXPECT_TRUE(M2->isDistinct());
277   EXPECT_TRUE(M3->isDistinct());
278   EXPECT_TRUE(M4->isUniqued());
279   EXPECT_EQ(M3, M4->getOperand(0));
280 
281   // Link into destination module.
282   auto Dst = std::make_unique<Module>("Linked", C);
283   ASSERT_TRUE(Dst.get());
284   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
285   Linker::linkModules(*Dst, std::move(Src));
286 
287   // Check that distinct metadata was moved, not cloned.  Even !4, the uniqued
288   // node, should effectively be moved, since its only operand hasn't changed.
289   F = &*Dst->begin();
290   BB = &F->getEntryBlock();
291   CI = cast<CallInst>(&BB->front());
292   RI = cast<ReturnInst>(BB->getTerminator());
293   NMD = &*Dst->named_metadata_begin();
294 
295   EXPECT_EQ(M0, F->getMetadata("attach"));
296   EXPECT_EQ(M1, cast<MetadataAsValue>(CI->getArgOperand(0))->getMetadata());
297   EXPECT_EQ(M2, RI->getMetadata("attach"));
298   EXPECT_EQ(M3, NMD->getOperand(0));
299   EXPECT_EQ(M4, NMD->getOperand(1));
300 
301   // Confirm a few things about the IR.  This shouldn't have changed.
302   EXPECT_TRUE(M0->isDistinct());
303   EXPECT_TRUE(M1->isDistinct());
304   EXPECT_TRUE(M2->isDistinct());
305   EXPECT_TRUE(M3->isDistinct());
306   EXPECT_TRUE(M4->isUniqued());
307   EXPECT_EQ(M3, M4->getOperand(0));
308 }
309 
310 TEST_F(LinkModuleTest, RemangleIntrinsics) {
311   LLVMContext C;
312   SMDiagnostic Err;
313 
314   // We load two modules inside the same context C. In both modules there is a
315   // "struct.rtx_def" type. In the module loaded the second (Bar) this type will
316   // be renamed to "struct.rtx_def.0". Check that the intrinsics which have this
317   // type in the signature are properly remangled.
318   const char *FooStr =
319     "%struct.rtx_def = type { i16 }\n"
320     "define void @foo(%struct.rtx_def %a) {\n"
321     "  call %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def %a)\n"
322     "  ret void\n"
323     "}\n"
324     "declare %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def)\n";
325 
326   const char *BarStr =
327     "%struct.rtx_def = type { i16 }\n"
328     "define void @bar(%struct.rtx_def %a) {\n"
329     "  call %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def %a)\n"
330     "  ret void\n"
331     "}\n"
332     "declare %struct.rtx_def @llvm.ssa.copy.s_struct.rtx_defs(%struct.rtx_def)\n";
333 
334   std::unique_ptr<Module> Foo = parseAssemblyString(FooStr, Err, C);
335   assert(Foo);
336   ASSERT_TRUE(Foo.get());
337   // Foo is loaded first, so the type and the intrinsic have theis original
338   // names.
339   ASSERT_TRUE(Foo->getFunction("llvm.ssa.copy.s_struct.rtx_defs"));
340   ASSERT_FALSE(Foo->getFunction("llvm.ssa.copy.s_struct.rtx_defs.0"));
341 
342   std::unique_ptr<Module> Bar = parseAssemblyString(BarStr, Err, C);
343   assert(Bar);
344   ASSERT_TRUE(Bar.get());
345   // Bar is loaded after Foo, so the type is renamed to struct.rtx_def.0. Check
346   // that the intrinsic is also renamed.
347   ASSERT_FALSE(Bar->getFunction("llvm.ssa.copy.s_struct.rtx_defs"));
348   ASSERT_TRUE(Bar->getFunction("llvm.ssa.copy.s_struct.rtx_def.0s"));
349 
350   // Link two modules together.
351   auto Dst = std::make_unique<Module>("Linked", C);
352   ASSERT_TRUE(Dst.get());
353   Ctx.setDiagnosticHandlerCallBack(expectNoDiags);
354   bool Failed = Linker::linkModules(*Foo, std::move(Bar));
355   ASSERT_FALSE(Failed);
356 
357   // "struct.rtx_def" from Foo and "struct.rtx_def.0" from Bar are isomorphic
358   // types, so they must be uniquified by linker. Check that they use the same
359   // intrinsic definition.
360   Function *F = Foo->getFunction("llvm.ssa.copy.s_struct.rtx_defs");
361   ASSERT_EQ(F->getNumUses(), (unsigned)2);
362 }
363 
364 } // end anonymous namespace
365