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>
28using namespace clang;
29
30namespace {
31  class CodeGeneratorImpl : public CodeGenerator {
32    DiagnosticsEngine &Diags;
33    std::unique_ptr<const llvm::DataLayout> TD;
34    ASTContext *Ctx;
35    const CodeGenOptions CodeGenOpts;  // Intentionally copied in.
36  protected:
37    std::unique_ptr<llvm::Module> M;
38    std::unique_ptr<CodeGen::CodeGenModule> Builder;
39
40  public:
41    CodeGeneratorImpl(DiagnosticsEngine &diags, const std::string& ModuleName,
42                      const CodeGenOptions &CGO, llvm::LLVMContext& C)
43      : Diags(diags), CodeGenOpts(CGO),
44        M(new llvm::Module(ModuleName, C)) {}
45
46    virtual ~CodeGeneratorImpl() {}
47
48    llvm::Module* GetModule() override {
49      return M.get();
50    }
51
52    const Decl *GetDeclForMangledName(StringRef MangledName) override {
53      GlobalDecl Result;
54      if (!Builder->lookupRepresentativeDecl(MangledName, Result))
55        return nullptr;
56      const Decl *D = Result.getCanonicalDecl().getDecl();
57      if (auto FD = dyn_cast<FunctionDecl>(D)) {
58        if (FD->hasBody(FD))
59          return FD;
60      } else if (auto TD = dyn_cast<TagDecl>(D)) {
61        if (auto Def = TD->getDefinition())
62          return Def;
63      }
64      return D;
65    }
66
67    llvm::Module *ReleaseModule() override { return M.release(); }
68
69    void Initialize(ASTContext &Context) override {
70      Ctx = &Context;
71
72      M->setTargetTriple(Ctx->getTargetInfo().getTriple().getTriple());
73      M->setDataLayout(Ctx->getTargetInfo().getTargetDescription());
74      TD.reset(new llvm::DataLayout(Ctx->getTargetInfo().getTargetDescription()));
75      Builder.reset(new CodeGen::CodeGenModule(Context, CodeGenOpts, *M, *TD,
76                                               Diags));
77
78      for (size_t i = 0, e = CodeGenOpts.DependentLibraries.size(); i < e; ++i)
79        HandleDependentLibrary(CodeGenOpts.DependentLibraries[i]);
80    }
81
82    void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) override {
83      if (Diags.hasErrorOccurred())
84        return;
85
86      Builder->HandleCXXStaticMemberVarInstantiation(VD);
87    }
88
89    bool HandleTopLevelDecl(DeclGroupRef DG) override {
90      if (Diags.hasErrorOccurred())
91        return true;
92
93      // Make sure to emit all elements of a Decl.
94      for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
95        Builder->EmitTopLevelDecl(*I);
96
97      // Emit any deferred inline method definitions.
98      for (CXXMethodDecl *MD : DeferredInlineMethodDefinitions)
99        Builder->EmitTopLevelDecl(MD);
100      DeferredInlineMethodDefinitions.clear();
101
102      return true;
103    }
104
105    void HandleInlineMethodDefinition(CXXMethodDecl *D) override {
106      if (Diags.hasErrorOccurred())
107        return;
108
109      assert(D->doesThisDeclarationHaveABody());
110
111      // We may want to emit this definition. However, that decision might be
112      // based on computing the linkage, and we have to defer that in case we
113      // are inside of something that will change the method's final linkage,
114      // e.g.
115      //   typedef struct {
116      //     void bar();
117      //     void foo() { bar(); }
118      //   } A;
119      DeferredInlineMethodDefinitions.push_back(D);
120    }
121
122    /// HandleTagDeclDefinition - This callback is invoked each time a TagDecl
123    /// to (e.g. struct, union, enum, class) is completed. This allows the
124    /// client hack on the type, which can occur at any point in the file
125    /// (because these can be defined in declspecs).
126    void HandleTagDeclDefinition(TagDecl *D) override {
127      if (Diags.hasErrorOccurred())
128        return;
129
130      Builder->UpdateCompletedType(D);
131    }
132
133    void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
134      if (Diags.hasErrorOccurred())
135        return;
136
137      if (CodeGen::CGDebugInfo *DI = Builder->getModuleDebugInfo())
138        if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
139          DI->completeRequiredType(RD);
140    }
141
142    void HandleTranslationUnit(ASTContext &Ctx) override {
143      if (Diags.hasErrorOccurred()) {
144        if (Builder)
145          Builder->clear();
146        M.reset();
147        return;
148      }
149
150      if (Builder)
151        Builder->Release();
152    }
153
154    void CompleteTentativeDefinition(VarDecl *D) override {
155      if (Diags.hasErrorOccurred())
156        return;
157
158      Builder->EmitTentativeDefinition(D);
159    }
160
161    void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) override {
162      if (Diags.hasErrorOccurred())
163        return;
164
165      Builder->EmitVTable(RD, DefinitionRequired);
166    }
167
168    void HandleLinkerOptionPragma(llvm::StringRef Opts) override {
169      Builder->AppendLinkerOptions(Opts);
170    }
171
172    void HandleDetectMismatch(llvm::StringRef Name,
173                              llvm::StringRef Value) override {
174      Builder->AddDetectMismatch(Name, Value);
175    }
176
177    void HandleDependentLibrary(llvm::StringRef Lib) override {
178      Builder->AddDependentLib(Lib);
179    }
180
181  private:
182    std::vector<CXXMethodDecl *> DeferredInlineMethodDefinitions;
183  };
184}
185
186void CodeGenerator::anchor() { }
187
188CodeGenerator *clang::CreateLLVMCodeGen(DiagnosticsEngine &Diags,
189                                        const std::string& ModuleName,
190                                        const CodeGenOptions &CGO,
191                                        const TargetOptions &/*TO*/,
192                                        llvm::LLVMContext& C) {
193  return new CodeGeneratorImpl(Diags, ModuleName, CGO, C);
194}
195