clang  3.9.0
ModuleBuilder.cpp
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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 
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"
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;
48  HandlingTopLevelDeclRAII(CodeGeneratorImpl &Self,
49  bool EmitDeferred = true)
50  : Self(Self), EmitDeferred(EmitDeferred) {
51  ++Self.HandlingTopLevelDecls;
52  }
53  ~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:
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 
81  ~CodeGeneratorImpl() override {
82  // There should normally not be any leftover inline method definitions.
83  assert(DeferredInlineMethodDefinitions.empty() ||
84  Diags.hasErrorOccurred());
85  }
86 
87  CodeGenModule &CGM() {
88  return *Builder;
89  }
90 
91  llvm::Module *GetModule() {
92  return M.get();
93  }
94 
95  llvm::Module *ReleaseModule() {
96  return M.release();
97  }
98 
99  const Decl *GetDeclForMangledName(StringRef MangledName) {
101  if (!Builder->lookupRepresentativeDecl(MangledName, Result))
102  return nullptr;
103  const Decl *D = Result.getCanonicalDecl().getDecl();
104  if (auto FD = dyn_cast<FunctionDecl>(D)) {
105  if (FD->hasBody(FD))
106  return FD;
107  } else if (auto TD = dyn_cast<TagDecl>(D)) {
108  if (auto Def = TD->getDefinition())
109  return Def;
110  }
111  return D;
112  }
113 
114  llvm::Constant *GetAddrOfGlobal(GlobalDecl global, bool isForDefinition) {
115  return Builder->GetAddrOfGlobal(global, isForDefinition);
116  }
117 
118  void Initialize(ASTContext &Context) override {
119  Ctx = &Context;
120 
121  M->setTargetTriple(Ctx->getTargetInfo().getTriple().getTriple());
122  M->setDataLayout(Ctx->getTargetInfo().getDataLayout());
123  Builder.reset(new CodeGen::CodeGenModule(Context, HeaderSearchOpts,
124  PreprocessorOpts, CodeGenOpts,
125  *M, Diags, CoverageInfo));
126 
127  for (auto &&Lib : CodeGenOpts.DependentLibraries)
128  Builder->AddDependentLib(Lib);
129  for (auto &&Opt : CodeGenOpts.LinkerOptions)
130  Builder->AppendLinkerOptions(Opt);
131  }
132 
133  void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) override {
134  if (Diags.hasErrorOccurred())
135  return;
136 
137  Builder->HandleCXXStaticMemberVarInstantiation(VD);
138  }
139 
140  bool HandleTopLevelDecl(DeclGroupRef DG) override {
141  if (Diags.hasErrorOccurred())
142  return true;
143 
144  HandlingTopLevelDeclRAII HandlingDecl(*this);
145 
146  // Make sure to emit all elements of a Decl.
147  for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
148  Builder->EmitTopLevelDecl(*I);
149 
150  return true;
151  }
152 
153  void EmitDeferredDecls() {
154  if (DeferredInlineMethodDefinitions.empty())
155  return;
156 
157  // Emit any deferred inline method definitions. Note that more deferred
158  // methods may be added during this loop, since ASTConsumer callbacks
159  // can be invoked if AST inspection results in declarations being added.
160  HandlingTopLevelDeclRAII HandlingDecl(*this);
161  for (unsigned I = 0; I != DeferredInlineMethodDefinitions.size(); ++I)
162  Builder->EmitTopLevelDecl(DeferredInlineMethodDefinitions[I]);
163  DeferredInlineMethodDefinitions.clear();
164  }
165 
166  void HandleInlineFunctionDefinition(FunctionDecl *D) override {
167  if (Diags.hasErrorOccurred())
168  return;
169 
170  assert(D->doesThisDeclarationHaveABody());
171 
172  // Handle friend functions.
173  if (D->isInIdentifierNamespace(Decl::IDNS_OrdinaryFriend)) {
174  if (Ctx->getTargetInfo().getCXXABI().isMicrosoft()
175  && !D->getLexicalDeclContext()->isDependentContext())
176  Builder->EmitTopLevelDecl(D);
177  return;
178  }
179 
180  // Otherwise, must be a method.
181  auto MD = cast<CXXMethodDecl>(D);
182 
183  // We may want to emit this definition. However, that decision might be
184  // based on computing the linkage, and we have to defer that in case we
185  // are inside of something that will change the method's final linkage,
186  // e.g.
187  // typedef struct {
188  // void bar();
189  // void foo() { bar(); }
190  // } A;
191  DeferredInlineMethodDefinitions.push_back(MD);
192 
193  // Provide some coverage mapping even for methods that aren't emitted.
194  // Don't do this for templated classes though, as they may not be
195  // instantiable.
196  if (!MD->getParent()->getDescribedClassTemplate())
197  Builder->AddDeferredUnusedCoverageMapping(MD);
198  }
199 
200  /// HandleTagDeclDefinition - This callback is invoked each time a TagDecl
201  /// to (e.g. struct, union, enum, class) is completed. This allows the
202  /// client hack on the type, which can occur at any point in the file
203  /// (because these can be defined in declspecs).
204  void HandleTagDeclDefinition(TagDecl *D) override {
205  if (Diags.hasErrorOccurred())
206  return;
207 
208  // Don't allow re-entrant calls to CodeGen triggered by PCH
209  // deserialization to emit deferred decls.
210  HandlingTopLevelDeclRAII HandlingDecl(*this, /*EmitDeferred=*/false);
211 
212  Builder->UpdateCompletedType(D);
213 
214  // For MSVC compatibility, treat declarations of static data members with
215  // inline initializers as definitions.
216  if (Ctx->getTargetInfo().getCXXABI().isMicrosoft()) {
217  for (Decl *Member : D->decls()) {
218  if (VarDecl *VD = dyn_cast<VarDecl>(Member)) {
219  if (Ctx->isMSStaticDataMemberInlineDefinition(VD) &&
220  Ctx->DeclMustBeEmitted(VD)) {
221  Builder->EmitGlobal(VD);
222  }
223  }
224  }
225  }
226  // For OpenMP emit declare reduction functions, if required.
227  if (Ctx->getLangOpts().OpenMP) {
228  for (Decl *Member : D->decls()) {
229  if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(Member)) {
230  if (Ctx->DeclMustBeEmitted(DRD))
231  Builder->EmitGlobal(DRD);
232  }
233  }
234  }
235  }
236 
237  void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
238  if (Diags.hasErrorOccurred())
239  return;
240 
241  // Don't allow re-entrant calls to CodeGen triggered by PCH
242  // deserialization to emit deferred decls.
243  HandlingTopLevelDeclRAII HandlingDecl(*this, /*EmitDeferred=*/false);
244 
245  if (CodeGen::CGDebugInfo *DI = Builder->getModuleDebugInfo())
246  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
247  DI->completeRequiredType(RD);
248  }
249 
250  void HandleTranslationUnit(ASTContext &Ctx) override {
251  // Release the Builder when there is no error.
252  if (!Diags.hasErrorOccurred() && Builder)
253  Builder->Release();
254 
255  // If there are errors before or when releasing the Builder, reset
256  // the module to stop here before invoking the backend.
257  if (Diags.hasErrorOccurred()) {
258  if (Builder)
259  Builder->clear();
260  M.reset();
261  return;
262  }
263  }
264 
265  void AssignInheritanceModel(CXXRecordDecl *RD) override {
266  if (Diags.hasErrorOccurred())
267  return;
268 
269  Builder->RefreshTypeCacheForClass(RD);
270  }
271 
272  void CompleteTentativeDefinition(VarDecl *D) override {
273  if (Diags.hasErrorOccurred())
274  return;
275 
276  Builder->EmitTentativeDefinition(D);
277  }
278 
279  void HandleVTable(CXXRecordDecl *RD) override {
280  if (Diags.hasErrorOccurred())
281  return;
282 
283  Builder->EmitVTable(RD);
284  }
285  };
286 }
287 
288 void CodeGenerator::anchor() { }
289 
291  return static_cast<CodeGeneratorImpl*>(this)->CGM();
292 }
293 
294 llvm::Module *CodeGenerator::GetModule() {
295  return static_cast<CodeGeneratorImpl*>(this)->GetModule();
296 }
297 
299  return static_cast<CodeGeneratorImpl*>(this)->ReleaseModule();
300 }
301 
302 const Decl *CodeGenerator::GetDeclForMangledName(llvm::StringRef name) {
303  return static_cast<CodeGeneratorImpl*>(this)->GetDeclForMangledName(name);
304 }
305 
307  bool isForDefinition) {
308  return static_cast<CodeGeneratorImpl*>(this)
309  ->GetAddrOfGlobal(global, isForDefinition);
310 }
311 
313  DiagnosticsEngine &Diags, llvm::StringRef ModuleName,
314  const HeaderSearchOptions &HeaderSearchOpts,
315  const PreprocessorOptions &PreprocessorOpts, const CodeGenOptions &CGO,
316  llvm::LLVMContext &C, CoverageSourceInfo *CoverageInfo) {
317  return new CodeGeneratorImpl(Diags, ModuleName, HeaderSearchOpts,
318  PreprocessorOpts, CGO, C, CoverageInfo);
319 }
Defines the clang::ASTContext interface.
llvm::Constant * GetAddrOfGlobal(GlobalDecl decl, bool isForDefinition)
Return the LLVM address of the given global entity.
FunctionDecl - An instance of this class is created to represent a function declaration or definition...
Definition: Decl.h:1561
decl_range decls() const
decls_begin/decls_end - Iterate over the declarations stored in this context.
Definition: DeclBase.h:1453
iterator end()
Definition: DeclGroup.h:108
bool isDependentContext() const
Determines whether this context is dependent on a template parameter.
Definition: DeclBase.cpp:922
Stores additional source code information like skipped ranges which is required by the coverage mappi...
PreprocessorOptions - This class is used for passing the various options used in preprocessor initial...
llvm::Module * ReleaseModule()
Release ownership of the module to the caller.
VarDecl - An instance of this class is created to represent a variable declaration or definition...
Definition: Decl.h:768
This class gathers all debug information during compilation and is responsible for emitting to llvm g...
Definition: CGDebugInfo.h:52
GlobalDecl getCanonicalDecl() const
Definition: GlobalDecl.h:54
RecordDecl - Represents a struct/union/class.
Definition: Decl.h:3253
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:92
const Decl * getDecl() const
Definition: GlobalDecl.h:62
Describes a module or submodule.
Definition: Basic/Module.h:47
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:135
iterator begin()
Definition: DeclGroup.h:102
CodeGenerator * CreateLLVMCodeGen(DiagnosticsEngine &Diags, llvm::StringRef ModuleName, const HeaderSearchOptions &HeaderSearchOpts, const PreprocessorOptions &PreprocessorOpts, const CodeGenOptions &CGO, llvm::LLVMContext &C, CoverageSourceInfo *CoverageInfo=nullptr)
CreateLLVMCodeGen - Create a CodeGenerator instance.
The primary public interface to the Clang code generator.
Definition: ModuleBuilder.h:42
detail::InMemoryDirectory::const_iterator I
ASTContext * Context
llvm::Module * GetModule()
Return the module that this code generator is building into.
The result type of a method or function.
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:29
CodeGen::CodeGenModule & CGM()
Return an opaque reference to the CodeGenModule object, which can be used in various secondary APIs...
bool doesThisDeclarationHaveABody() const
doesThisDeclarationHaveABody - Returns whether this specific declaration of the function has a body -...
Definition: Decl.h:1821
const Decl * GetDeclForMangledName(llvm::StringRef MangledName)
Given a mangled name, return a declaration which mangles that way which has been added to this code g...
TagDecl - Represents the declaration of a struct/union/class/enum.
Definition: Decl.h:2727
This class organizes the cross-function state that is used while generating LLVM code.
detail::InMemoryDirectory::const_iterator E
Defines the Diagnostic-related interfaces.
CodeGenOptions - Track various options which control how the code is optimized and passed to the back...
Represents a C++ struct/union/class.
Definition: DeclCXX.h:263
BoundNodesTreeBuilder *const Builder
Defines the clang::TargetInfo interface.
HeaderSearchOptions - Helper class for storing options related to the initialization of the HeaderSea...