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 "CodeGenModule.h"
16 #include "CGDebugInfo.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/OwningPtr.h"
24 #include "llvm/ADT/StringRef.h"
25 #include "llvm/IR/DataLayout.h"
26 #include "llvm/IR/LLVMContext.h"
27 #include "llvm/IR/Module.h"
28 using namespace clang;
29 
30 namespace {
31   class CodeGeneratorImpl : public CodeGenerator {
32     DiagnosticsEngine &Diags;
33     OwningPtr<const llvm::DataLayout> TD;
34     ASTContext *Ctx;
35     const CodeGenOptions CodeGenOpts;  // Intentionally copied in.
36   protected:
37     OwningPtr<llvm::Module> M;
38     OwningPtr<CodeGen::CodeGenModule> Builder;
39   public:
40     CodeGeneratorImpl(DiagnosticsEngine &diags, const std::string& ModuleName,
41                       const CodeGenOptions &CGO, llvm::LLVMContext& C)
42       : Diags(diags), CodeGenOpts(CGO),
43         M(new llvm::Module(ModuleName, C)) {}
44 
45     virtual ~CodeGeneratorImpl() {}
46 
47     virtual llvm::Module* GetModule() {
48       return M.get();
49     }
50 
51     virtual llvm::Module* ReleaseModule() {
52       return M.take();
53     }
54 
55     virtual void Initialize(ASTContext &Context) {
56       Ctx = &Context;
57 
58       M->setTargetTriple(Ctx->getTargetInfo().getTriple().getTriple());
59       M->setDataLayout(Ctx->getTargetInfo().getTargetDescription());
60       TD.reset(new llvm::DataLayout(Ctx->getTargetInfo().getTargetDescription()));
61       Builder.reset(new CodeGen::CodeGenModule(Context, CodeGenOpts, *M, *TD,
62                                                Diags));
63 
64       for (size_t i = 0, e = CodeGenOpts.DependentLibraries.size(); i < e; ++i)
65         HandleDependentLibrary(CodeGenOpts.DependentLibraries[i]);
66     }
67 
68     virtual void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
69       if (Diags.hasErrorOccurred())
70         return;
71 
72       Builder->HandleCXXStaticMemberVarInstantiation(VD);
73     }
74 
75     virtual bool HandleTopLevelDecl(DeclGroupRef DG) {
76       if (Diags.hasErrorOccurred())
77         return true;
78 
79       // Make sure to emit all elements of a Decl.
80       for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
81         Builder->EmitTopLevelDecl(*I);
82       return true;
83     }
84 
85     /// HandleTagDeclDefinition - This callback is invoked each time a TagDecl
86     /// to (e.g. struct, union, enum, class) is completed. This allows the
87     /// client hack on the type, which can occur at any point in the file
88     /// (because these can be defined in declspecs).
89     virtual void HandleTagDeclDefinition(TagDecl *D) {
90       if (Diags.hasErrorOccurred())
91         return;
92 
93       Builder->UpdateCompletedType(D);
94 
95       // In C++, we may have member functions that need to be emitted at this
96       // point.
97       if (Ctx->getLangOpts().CPlusPlus && !D->isDependentContext()) {
98         for (DeclContext::decl_iterator M = D->decls_begin(),
99                                      MEnd = D->decls_end();
100              M != MEnd; ++M)
101           if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(*M))
102             if (Method->doesThisDeclarationHaveABody() &&
103                 (Method->hasAttr<UsedAttr>() ||
104                  Method->hasAttr<ConstructorAttr>()))
105               Builder->EmitTopLevelDecl(Method);
106       }
107     }
108 
109     virtual void HandleTagDeclRequiredDefinition(const TagDecl *D) LLVM_OVERRIDE {
110       if (Diags.hasErrorOccurred())
111         return;
112 
113       if (CodeGen::CGDebugInfo *DI = Builder->getModuleDebugInfo())
114         if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
115           DI->completeRequiredType(RD);
116     }
117 
118     virtual void HandleTranslationUnit(ASTContext &Ctx) {
119       if (Diags.hasErrorOccurred()) {
120         M.reset();
121         return;
122       }
123 
124       if (Builder)
125         Builder->Release();
126     }
127 
128     virtual void CompleteTentativeDefinition(VarDecl *D) {
129       if (Diags.hasErrorOccurred())
130         return;
131 
132       Builder->EmitTentativeDefinition(D);
133     }
134 
135     virtual void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) {
136       if (Diags.hasErrorOccurred())
137         return;
138 
139       Builder->EmitVTable(RD, DefinitionRequired);
140     }
141 
142     virtual void HandleLinkerOptionPragma(llvm::StringRef Opts) {
143       Builder->AppendLinkerOptions(Opts);
144     }
145 
146     virtual void HandleDetectMismatch(llvm::StringRef Name,
147                                       llvm::StringRef Value) {
148       Builder->AddDetectMismatch(Name, Value);
149     }
150 
151     virtual void HandleDependentLibrary(llvm::StringRef Lib) {
152       Builder->AddDependentLib(Lib);
153     }
154   };
155 }
156 
157 void CodeGenerator::anchor() { }
158 
159 CodeGenerator *clang::CreateLLVMCodeGen(DiagnosticsEngine &Diags,
160                                         const std::string& ModuleName,
161                                         const CodeGenOptions &CGO,
162                                         const TargetOptions &/*TO*/,
163                                         llvm::LLVMContext& C) {
164   return new CodeGeneratorImpl(Diags, ModuleName, CGO, C);
165 }
166