1 //===--- ModuleBuilder.cpp - Emit LLVM Code from ASTs ---------------------===//
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 // This builds an AST and converts it to LLVM Code.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "clang/CodeGen/ModuleBuilder.h"
15 #include "CGDebugInfo.h"
16 #include "CodeGenModule.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/DeclObjC.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/Basic/Diagnostic.h"
21 #include "clang/Basic/TargetInfo.h"
22 #include "clang/Frontend/CodeGenOptions.h"
23 #include "llvm/ADT/StringRef.h"
24 #include "llvm/IR/DataLayout.h"
25 #include "llvm/IR/LLVMContext.h"
26 #include "llvm/IR/Module.h"
27 #include <memory>
28
29 using namespace clang;
30 using namespace CodeGen;
31
32 namespace {
33 class CodeGeneratorImpl : public CodeGenerator {
34 DiagnosticsEngine &Diags;
35 ASTContext *Ctx;
36 const HeaderSearchOptions &HeaderSearchOpts; // Only used for debug info.
37 const PreprocessorOptions &PreprocessorOpts; // Only used for debug info.
38 const CodeGenOptions CodeGenOpts; // Intentionally copied in.
39
40 unsigned HandlingTopLevelDecls;
41
42 /// Use this when emitting decls to block re-entrant decl emission. It will
43 /// emit all deferred decls on scope exit. Set EmitDeferred to false if decl
44 /// emission must be deferred longer, like at the end of a tag definition.
45 struct HandlingTopLevelDeclRAII {
46 CodeGeneratorImpl &Self;
47 bool EmitDeferred;
HandlingTopLevelDeclRAII__anon765d2f370111::CodeGeneratorImpl::HandlingTopLevelDeclRAII48 HandlingTopLevelDeclRAII(CodeGeneratorImpl &Self,
49 bool EmitDeferred = true)
50 : Self(Self), EmitDeferred(EmitDeferred) {
51 ++Self.HandlingTopLevelDecls;
52 }
~HandlingTopLevelDeclRAII__anon765d2f370111::CodeGeneratorImpl::HandlingTopLevelDeclRAII53 ~HandlingTopLevelDeclRAII() {
54 unsigned Level = --Self.HandlingTopLevelDecls;
55 if (Level == 0 && EmitDeferred)
56 Self.EmitDeferredDecls();
57 }
58 };
59
60 CoverageSourceInfo *CoverageInfo;
61
62 protected:
63 std::unique_ptr<llvm::Module> M;
64 std::unique_ptr<CodeGen::CodeGenModule> Builder;
65
66 private:
67 SmallVector<CXXMethodDecl *, 8> DeferredInlineMethodDefinitions;
68
69 public:
CodeGeneratorImpl(DiagnosticsEngine & diags,llvm::StringRef ModuleName,const HeaderSearchOptions & HSO,const PreprocessorOptions & PPO,const CodeGenOptions & CGO,llvm::LLVMContext & C,CoverageSourceInfo * CoverageInfo=nullptr)70 CodeGeneratorImpl(DiagnosticsEngine &diags, llvm::StringRef ModuleName,
71 const HeaderSearchOptions &HSO,
72 const PreprocessorOptions &PPO, const CodeGenOptions &CGO,
73 llvm::LLVMContext &C,
74 CoverageSourceInfo *CoverageInfo = nullptr)
75 : Diags(diags), Ctx(nullptr), HeaderSearchOpts(HSO),
76 PreprocessorOpts(PPO), CodeGenOpts(CGO), HandlingTopLevelDecls(0),
77 CoverageInfo(CoverageInfo), M(new llvm::Module(ModuleName, C)) {
78 C.setDiscardValueNames(CGO.DiscardValueNames);
79 }
80
~CodeGeneratorImpl()81 ~CodeGeneratorImpl() override {
82 // There should normally not be any leftover inline method definitions.
83 assert(DeferredInlineMethodDefinitions.empty() ||
84 Diags.hasErrorOccurred());
85 }
86
CGM()87 CodeGenModule &CGM() {
88 return *Builder;
89 }
90
GetModule()91 llvm::Module *GetModule() {
92 return M.get();
93 }
94
getCGDebugInfo()95 CGDebugInfo *getCGDebugInfo() {
96 return Builder->getModuleDebugInfo();
97 }
98
ReleaseModule()99 llvm::Module *ReleaseModule() {
100 return M.release();
101 }
102
GetDeclForMangledName(StringRef MangledName)103 const Decl *GetDeclForMangledName(StringRef MangledName) {
104 GlobalDecl Result;
105 if (!Builder->lookupRepresentativeDecl(MangledName, Result))
106 return nullptr;
107 const Decl *D = Result.getCanonicalDecl().getDecl();
108 if (auto FD = dyn_cast<FunctionDecl>(D)) {
109 if (FD->hasBody(FD))
110 return FD;
111 } else if (auto TD = dyn_cast<TagDecl>(D)) {
112 if (auto Def = TD->getDefinition())
113 return Def;
114 }
115 return D;
116 }
117
GetAddrOfGlobal(GlobalDecl global,bool isForDefinition)118 llvm::Constant *GetAddrOfGlobal(GlobalDecl global, bool isForDefinition) {
119 return Builder->GetAddrOfGlobal(global, ForDefinition_t(isForDefinition));
120 }
121
StartModule(llvm::StringRef ModuleName,llvm::LLVMContext & C)122 llvm::Module *StartModule(llvm::StringRef ModuleName,
123 llvm::LLVMContext &C) {
124 assert(!M && "Replacing existing Module?");
125 M.reset(new llvm::Module(ModuleName, C));
126 Initialize(*Ctx);
127 return M.get();
128 }
129
Initialize(ASTContext & Context)130 void Initialize(ASTContext &Context) override {
131 Ctx = &Context;
132
133 M->setTargetTriple(Ctx->getTargetInfo().getTriple().getTriple());
134 M->setDataLayout(Ctx->getTargetInfo().getDataLayout());
135 Builder.reset(new CodeGen::CodeGenModule(Context, HeaderSearchOpts,
136 PreprocessorOpts, CodeGenOpts,
137 *M, Diags, CoverageInfo));
138
139 for (auto &&Lib : CodeGenOpts.DependentLibraries)
140 Builder->AddDependentLib(Lib);
141 for (auto &&Opt : CodeGenOpts.LinkerOptions)
142 Builder->AppendLinkerOptions(Opt);
143 }
144
HandleCXXStaticMemberVarInstantiation(VarDecl * VD)145 void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) override {
146 if (Diags.hasErrorOccurred())
147 return;
148
149 Builder->HandleCXXStaticMemberVarInstantiation(VD);
150 }
151
HandleTopLevelDecl(DeclGroupRef DG)152 bool HandleTopLevelDecl(DeclGroupRef DG) override {
153 if (Diags.hasErrorOccurred())
154 return true;
155
156 HandlingTopLevelDeclRAII HandlingDecl(*this);
157
158 // Make sure to emit all elements of a Decl.
159 for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
160 Builder->EmitTopLevelDecl(*I);
161
162 return true;
163 }
164
EmitDeferredDecls()165 void EmitDeferredDecls() {
166 if (DeferredInlineMethodDefinitions.empty())
167 return;
168
169 // Emit any deferred inline method definitions. Note that more deferred
170 // methods may be added during this loop, since ASTConsumer callbacks
171 // can be invoked if AST inspection results in declarations being added.
172 HandlingTopLevelDeclRAII HandlingDecl(*this);
173 for (unsigned I = 0; I != DeferredInlineMethodDefinitions.size(); ++I)
174 Builder->EmitTopLevelDecl(DeferredInlineMethodDefinitions[I]);
175 DeferredInlineMethodDefinitions.clear();
176 }
177
HandleInlineFunctionDefinition(FunctionDecl * D)178 void HandleInlineFunctionDefinition(FunctionDecl *D) override {
179 if (Diags.hasErrorOccurred())
180 return;
181
182 assert(D->doesThisDeclarationHaveABody());
183
184 // Handle friend functions.
185 if (D->isInIdentifierNamespace(Decl::IDNS_OrdinaryFriend)) {
186 if (Ctx->getTargetInfo().getCXXABI().isMicrosoft()
187 && !D->getLexicalDeclContext()->isDependentContext())
188 Builder->EmitTopLevelDecl(D);
189 return;
190 }
191
192 // Otherwise, must be a method.
193 auto MD = cast<CXXMethodDecl>(D);
194
195 // We may want to emit this definition. However, that decision might be
196 // based on computing the linkage, and we have to defer that in case we
197 // are inside of something that will change the method's final linkage,
198 // e.g.
199 // typedef struct {
200 // void bar();
201 // void foo() { bar(); }
202 // } A;
203 DeferredInlineMethodDefinitions.push_back(MD);
204
205 // Provide some coverage mapping even for methods that aren't emitted.
206 // Don't do this for templated classes though, as they may not be
207 // instantiable.
208 if (!MD->getParent()->isDependentContext())
209 Builder->AddDeferredUnusedCoverageMapping(MD);
210 }
211
212 /// HandleTagDeclDefinition - This callback is invoked each time a TagDecl
213 /// to (e.g. struct, union, enum, class) is completed. This allows the
214 /// client hack on the type, which can occur at any point in the file
215 /// (because these can be defined in declspecs).
HandleTagDeclDefinition(TagDecl * D)216 void HandleTagDeclDefinition(TagDecl *D) override {
217 if (Diags.hasErrorOccurred())
218 return;
219
220 // Don't allow re-entrant calls to CodeGen triggered by PCH
221 // deserialization to emit deferred decls.
222 HandlingTopLevelDeclRAII HandlingDecl(*this, /*EmitDeferred=*/false);
223
224 Builder->UpdateCompletedType(D);
225
226 // For MSVC compatibility, treat declarations of static data members with
227 // inline initializers as definitions.
228 if (Ctx->getTargetInfo().getCXXABI().isMicrosoft()) {
229 for (Decl *Member : D->decls()) {
230 if (VarDecl *VD = dyn_cast<VarDecl>(Member)) {
231 if (Ctx->isMSStaticDataMemberInlineDefinition(VD) &&
232 Ctx->DeclMustBeEmitted(VD)) {
233 Builder->EmitGlobal(VD);
234 }
235 }
236 }
237 }
238 // For OpenMP emit declare reduction functions, if required.
239 if (Ctx->getLangOpts().OpenMP) {
240 for (Decl *Member : D->decls()) {
241 if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(Member)) {
242 if (Ctx->DeclMustBeEmitted(DRD))
243 Builder->EmitGlobal(DRD);
244 }
245 }
246 }
247 }
248
HandleTagDeclRequiredDefinition(const TagDecl * D)249 void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
250 if (Diags.hasErrorOccurred())
251 return;
252
253 // Don't allow re-entrant calls to CodeGen triggered by PCH
254 // deserialization to emit deferred decls.
255 HandlingTopLevelDeclRAII HandlingDecl(*this, /*EmitDeferred=*/false);
256
257 if (CodeGen::CGDebugInfo *DI = Builder->getModuleDebugInfo())
258 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
259 DI->completeRequiredType(RD);
260 }
261
HandleTranslationUnit(ASTContext & Ctx)262 void HandleTranslationUnit(ASTContext &Ctx) override {
263 // Release the Builder when there is no error.
264 if (!Diags.hasErrorOccurred() && Builder)
265 Builder->Release();
266
267 // If there are errors before or when releasing the Builder, reset
268 // the module to stop here before invoking the backend.
269 if (Diags.hasErrorOccurred()) {
270 if (Builder)
271 Builder->clear();
272 M.reset();
273 return;
274 }
275 }
276
AssignInheritanceModel(CXXRecordDecl * RD)277 void AssignInheritanceModel(CXXRecordDecl *RD) override {
278 if (Diags.hasErrorOccurred())
279 return;
280
281 Builder->RefreshTypeCacheForClass(RD);
282 }
283
CompleteTentativeDefinition(VarDecl * D)284 void CompleteTentativeDefinition(VarDecl *D) override {
285 if (Diags.hasErrorOccurred())
286 return;
287
288 Builder->EmitTentativeDefinition(D);
289 }
290
HandleVTable(CXXRecordDecl * RD)291 void HandleVTable(CXXRecordDecl *RD) override {
292 if (Diags.hasErrorOccurred())
293 return;
294
295 Builder->EmitVTable(RD);
296 }
297 };
298 }
299
anchor()300 void CodeGenerator::anchor() { }
301
CGM()302 CodeGenModule &CodeGenerator::CGM() {
303 return static_cast<CodeGeneratorImpl*>(this)->CGM();
304 }
305
GetModule()306 llvm::Module *CodeGenerator::GetModule() {
307 return static_cast<CodeGeneratorImpl*>(this)->GetModule();
308 }
309
ReleaseModule()310 llvm::Module *CodeGenerator::ReleaseModule() {
311 return static_cast<CodeGeneratorImpl*>(this)->ReleaseModule();
312 }
313
getCGDebugInfo()314 CGDebugInfo *CodeGenerator::getCGDebugInfo() {
315 return static_cast<CodeGeneratorImpl*>(this)->getCGDebugInfo();
316 }
317
GetDeclForMangledName(llvm::StringRef name)318 const Decl *CodeGenerator::GetDeclForMangledName(llvm::StringRef name) {
319 return static_cast<CodeGeneratorImpl*>(this)->GetDeclForMangledName(name);
320 }
321
GetAddrOfGlobal(GlobalDecl global,bool isForDefinition)322 llvm::Constant *CodeGenerator::GetAddrOfGlobal(GlobalDecl global,
323 bool isForDefinition) {
324 return static_cast<CodeGeneratorImpl*>(this)
325 ->GetAddrOfGlobal(global, isForDefinition);
326 }
327
StartModule(llvm::StringRef ModuleName,llvm::LLVMContext & C)328 llvm::Module *CodeGenerator::StartModule(llvm::StringRef ModuleName,
329 llvm::LLVMContext &C) {
330 return static_cast<CodeGeneratorImpl*>(this)->StartModule(ModuleName, C);
331 }
332
CreateLLVMCodeGen(DiagnosticsEngine & Diags,llvm::StringRef ModuleName,const HeaderSearchOptions & HeaderSearchOpts,const PreprocessorOptions & PreprocessorOpts,const CodeGenOptions & CGO,llvm::LLVMContext & C,CoverageSourceInfo * CoverageInfo)333 CodeGenerator *clang::CreateLLVMCodeGen(
334 DiagnosticsEngine &Diags, llvm::StringRef ModuleName,
335 const HeaderSearchOptions &HeaderSearchOpts,
336 const PreprocessorOptions &PreprocessorOpts, const CodeGenOptions &CGO,
337 llvm::LLVMContext &C, CoverageSourceInfo *CoverageInfo) {
338 return new CodeGeneratorImpl(Diags, ModuleName, HeaderSearchOpts,
339 PreprocessorOpts, CGO, C, CoverageInfo);
340 }
341