CodeGenModule.h revision 206084 
1//===--- CodeGenModule.h - Per-Module state for LLVM CodeGen ----*- C++ -*-===//
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 is the internal per-translation-unit state used for llvm translation.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef CLANG_CODEGEN_CODEGENMODULE_H
15#define CLANG_CODEGEN_CODEGENMODULE_H
16
17#include "clang/Basic/LangOptions.h"
18#include "clang/AST/Attr.h"
19#include "clang/AST/DeclCXX.h"
20#include "clang/AST/DeclObjC.h"
21#include "CGBlocks.h"
22#include "CGCall.h"
23#include "CGCXX.h"
24#include "CGVtable.h"
25#include "CodeGenTypes.h"
26#include "GlobalDecl.h"
27#include "Mangle.h"
28#include "llvm/Module.h"
29#include "llvm/ADT/DenseMap.h"
30#include "llvm/ADT/StringMap.h"
31#include "llvm/ADT/StringSet.h"
32#include "llvm/ADT/SmallPtrSet.h"
33#include "llvm/Support/ValueHandle.h"
34
35namespace llvm {
36  class Module;
37  class Constant;
38  class Function;
39  class GlobalValue;
40  class TargetData;
41  class FunctionType;
42  class LLVMContext;
43}
44
45namespace clang {
46  class TargetCodeGenInfo;
47  class ASTContext;
48  class FunctionDecl;
49  class IdentifierInfo;
50  class ObjCMethodDecl;
51  class ObjCImplementationDecl;
52  class ObjCCategoryImplDecl;
53  class ObjCProtocolDecl;
54  class ObjCEncodeExpr;
55  class BlockExpr;
56  class CharUnits;
57  class Decl;
58  class Expr;
59  class Stmt;
60  class StringLiteral;
61  class NamedDecl;
62  class ValueDecl;
63  class VarDecl;
64  class LangOptions;
65  class CodeGenOptions;
66  class Diagnostic;
67  class AnnotateAttr;
68  class CXXDestructorDecl;
69
70namespace CodeGen {
71
72  class CodeGenFunction;
73  class CGDebugInfo;
74  class CGObjCRuntime;
75  class MangleBuffer;
76
77/// CodeGenModule - This class organizes the cross-function state that is used
78/// while generating LLVM code.
79class CodeGenModule : public BlockModule {
80  CodeGenModule(const CodeGenModule&);  // DO NOT IMPLEMENT
81  void operator=(const CodeGenModule&); // DO NOT IMPLEMENT
82
83  typedef std::vector<std::pair<llvm::Constant*, int> > CtorList;
84
85  ASTContext &Context;
86  const LangOptions &Features;
87  const CodeGenOptions &CodeGenOpts;
88  llvm::Module &TheModule;
89  const llvm::TargetData &TheTargetData;
90  mutable const TargetCodeGenInfo *TheTargetCodeGenInfo;
91  Diagnostic &Diags;
92  CodeGenTypes Types;
93  MangleContext MangleCtx;
94
95  /// VTables - Holds information about C++ vtables.
96  CodeGenVTables VTables;
97
98  CGObjCRuntime* Runtime;
99  CGDebugInfo* DebugInfo;
100
101  llvm::Function *MemCpyFn;
102  llvm::Function *MemMoveFn;
103  llvm::Function *MemSetFn;
104
105  // WeakRefReferences - A set of references that have only been seen via
106  // a weakref so far. This is used to remove the weak of the reference if we ever
107  // see a direct reference or a definition.
108  llvm::SmallPtrSet<llvm::GlobalValue*, 10> WeakRefReferences;
109
110  /// DeferredDecls - This contains all the decls which have definitions but
111  /// which are deferred for emission and therefore should only be output if
112  /// they are actually used.  If a decl is in this, then it is known to have
113  /// not been referenced yet.
114  llvm::StringMap<GlobalDecl> DeferredDecls;
115
116  /// DeferredDeclsToEmit - This is a list of deferred decls which we have seen
117  /// that *are* actually referenced.  These get code generated when the module
118  /// is done.
119  std::vector<GlobalDecl> DeferredDeclsToEmit;
120
121  /// LLVMUsed - List of global values which are required to be
122  /// present in the object file; bitcast to i8*. This is used for
123  /// forcing visibility of symbols which may otherwise be optimized
124  /// out.
125  std::vector<llvm::WeakVH> LLVMUsed;
126
127  /// GlobalCtors - Store the list of global constructors and their respective
128  /// priorities to be emitted when the translation unit is complete.
129  CtorList GlobalCtors;
130
131  /// GlobalDtors - Store the list of global destructors and their respective
132  /// priorities to be emitted when the translation unit is complete.
133  CtorList GlobalDtors;
134
135  std::vector<llvm::Constant*> Annotations;
136
137  llvm::StringMap<llvm::Constant*> CFConstantStringMap;
138  llvm::StringMap<llvm::Constant*> ConstantStringMap;
139
140  /// CXXGlobalInits - Global variables with initializers that need to run
141  /// before main.
142  std::vector<llvm::Constant*> CXXGlobalInits;
143
144  /// CXXGlobalDtors - Global destructor functions and arguments that need to
145  /// run on termination.
146  std::vector<std::pair<llvm::Constant*,llvm::Constant*> > CXXGlobalDtors;
147
148  /// CFConstantStringClassRef - Cached reference to the class for constant
149  /// strings. This value has type int * but is actually an Obj-C class pointer.
150  llvm::Constant *CFConstantStringClassRef;
151
152  /// Lazily create the Objective-C runtime
153  void createObjCRuntime();
154
155  llvm::LLVMContext &VMContext;
156public:
157  CodeGenModule(ASTContext &C, const CodeGenOptions &CodeGenOpts,
158                llvm::Module &M, const llvm::TargetData &TD, Diagnostic &Diags);
159
160  ~CodeGenModule();
161
162  /// Release - Finalize LLVM code generation.
163  void Release();
164
165  /// getObjCRuntime() - Return a reference to the configured
166  /// Objective-C runtime.
167  CGObjCRuntime &getObjCRuntime() {
168    if (!Runtime) createObjCRuntime();
169    return *Runtime;
170  }
171
172  /// hasObjCRuntime() - Return true iff an Objective-C runtime has
173  /// been configured.
174  bool hasObjCRuntime() { return !!Runtime; }
175
176  CGDebugInfo *getDebugInfo() { return DebugInfo; }
177  ASTContext &getContext() const { return Context; }
178  const CodeGenOptions &getCodeGenOpts() const { return CodeGenOpts; }
179  const LangOptions &getLangOptions() const { return Features; }
180  llvm::Module &getModule() const { return TheModule; }
181  CodeGenTypes &getTypes() { return Types; }
182  MangleContext &getMangleContext() { return MangleCtx; }
183  CodeGenVTables &getVTables() { return VTables; }
184  Diagnostic &getDiags() const { return Diags; }
185  const llvm::TargetData &getTargetData() const { return TheTargetData; }
186  llvm::LLVMContext &getLLVMContext() { return VMContext; }
187  const TargetCodeGenInfo &getTargetCodeGenInfo() const;
188  bool isTargetDarwin() const;
189
190  /// getDeclVisibilityMode - Compute the visibility of the decl \arg D.
191  LangOptions::VisibilityMode getDeclVisibilityMode(const Decl *D) const;
192
193  /// setGlobalVisibility - Set the visibility for the given LLVM
194  /// GlobalValue.
195  void setGlobalVisibility(llvm::GlobalValue *GV, const Decl *D) const;
196
197  llvm::Constant *GetAddrOfGlobal(GlobalDecl GD) {
198    if (isa<CXXConstructorDecl>(GD.getDecl()))
199      return GetAddrOfCXXConstructor(cast<CXXConstructorDecl>(GD.getDecl()),
200                                     GD.getCtorType());
201    else if (isa<CXXDestructorDecl>(GD.getDecl()))
202      return GetAddrOfCXXDestructor(cast<CXXDestructorDecl>(GD.getDecl()),
203                                     GD.getDtorType());
204    else if (isa<FunctionDecl>(GD.getDecl()))
205      return GetAddrOfFunction(GD);
206    else
207      return GetAddrOfGlobalVar(cast<VarDecl>(GD.getDecl()));
208  }
209
210  /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
211  /// given global variable.  If Ty is non-null and if the global doesn't exist,
212  /// then it will be greated with the specified type instead of whatever the
213  /// normal requested type would be.
214  llvm::Constant *GetAddrOfGlobalVar(const VarDecl *D,
215                                     const llvm::Type *Ty = 0);
216
217  /// GetAddrOfFunction - Return the address of the given function.  If Ty is
218  /// non-null, then this function will use the specified type if it has to
219  /// create it.
220  llvm::Constant *GetAddrOfFunction(GlobalDecl GD,
221                                    const llvm::Type *Ty = 0);
222
223  /// GetAddrOfRTTIDescriptor - Get the address of the RTTI descriptor
224  /// for the given type.
225  llvm::Constant *GetAddrOfRTTIDescriptor(QualType Ty);
226
227  /// GetAddrOfThunk - Get the address of the thunk for the given global decl.
228  llvm::Constant *GetAddrOfThunk(GlobalDecl GD, const ThunkInfo &Thunk);
229
230  /// GetWeakRefReference - Get a reference to the target of VD.
231  llvm::Constant *GetWeakRefReference(const ValueDecl *VD);
232
233  /// GetNonVirtualBaseClassOffset - Returns the offset from a derived class to
234  /// its base class. Returns null if the offset is 0.
235  llvm::Constant *
236  GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
237                               const CXXRecordDecl *BaseClassDecl);
238
239  /// GetStringForStringLiteral - Return the appropriate bytes for a string
240  /// literal, properly padded to match the literal type. If only the address of
241  /// a constant is needed consider using GetAddrOfConstantStringLiteral.
242  std::string GetStringForStringLiteral(const StringLiteral *E);
243
244  /// GetAddrOfConstantCFString - Return a pointer to a constant CFString object
245  /// for the given string.
246  llvm::Constant *GetAddrOfConstantCFString(const StringLiteral *Literal);
247
248  /// GetAddrOfConstantStringFromLiteral - Return a pointer to a constant array
249  /// for the given string literal.
250  llvm::Constant *GetAddrOfConstantStringFromLiteral(const StringLiteral *S);
251
252  /// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
253  /// array for the given ObjCEncodeExpr node.
254  llvm::Constant *GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *);
255
256  /// GetAddrOfConstantString - Returns a pointer to a character array
257  /// containing the literal. This contents are exactly that of the given
258  /// string, i.e. it will not be null terminated automatically; see
259  /// GetAddrOfConstantCString. Note that whether the result is actually a
260  /// pointer to an LLVM constant depends on Feature.WriteableStrings.
261  ///
262  /// The result has pointer to array type.
263  ///
264  /// \param GlobalName If provided, the name to use for the global
265  /// (if one is created).
266  llvm::Constant *GetAddrOfConstantString(const std::string& str,
267                                          const char *GlobalName=0);
268
269  /// GetAddrOfConstantCString - Returns a pointer to a character array
270  /// containing the literal and a terminating '\0' character. The result has
271  /// pointer to array type.
272  ///
273  /// \param GlobalName If provided, the name to use for the global (if one is
274  /// created).
275  llvm::Constant *GetAddrOfConstantCString(const std::string &str,
276                                           const char *GlobalName=0);
277
278  /// GetAddrOfCXXConstructor - Return the address of the constructor of the
279  /// given type.
280  llvm::GlobalValue *GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
281                                             CXXCtorType Type);
282
283  /// GetAddrOfCXXDestructor - Return the address of the constructor of the
284  /// given type.
285  llvm::GlobalValue *GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
286                                            CXXDtorType Type);
287
288  /// getBuiltinLibFunction - Given a builtin id for a function like
289  /// "__builtin_fabsf", return a Function* for "fabsf".
290  llvm::Value *getBuiltinLibFunction(const FunctionDecl *FD,
291                                     unsigned BuiltinID);
292
293  llvm::Function *getMemCpyFn();
294  llvm::Function *getMemMoveFn();
295  llvm::Function *getMemSetFn();
296  llvm::Function *getIntrinsic(unsigned IID, const llvm::Type **Tys = 0,
297                               unsigned NumTys = 0);
298
299  /// EmitTopLevelDecl - Emit code for a single top level declaration.
300  void EmitTopLevelDecl(Decl *D);
301
302  /// AddUsedGlobal - Add a global which should be forced to be
303  /// present in the object file; these are emitted to the llvm.used
304  /// metadata global.
305  void AddUsedGlobal(llvm::GlobalValue *GV);
306
307  void AddAnnotation(llvm::Constant *C) { Annotations.push_back(C); }
308
309  /// AddCXXDtorEntry - Add a destructor and object to add to the C++ global
310  /// destructor function.
311  void AddCXXDtorEntry(llvm::Constant *DtorFn, llvm::Constant *Object);
312
313  /// CreateRuntimeFunction - Create a new runtime function with the specified
314  /// type and name.
315  llvm::Constant *CreateRuntimeFunction(const llvm::FunctionType *Ty,
316                                        llvm::StringRef Name);
317  /// CreateRuntimeVariable - Create a new runtime global variable with the
318  /// specified type and name.
319  llvm::Constant *CreateRuntimeVariable(const llvm::Type *Ty,
320                                        llvm::StringRef Name);
321
322  void UpdateCompletedType(const TagDecl *TD) {
323    // Make sure that this type is translated.
324    Types.UpdateCompletedType(TD);
325  }
326
327  /// EmitConstantExpr - Try to emit the given expression as a
328  /// constant; returns 0 if the expression cannot be emitted as a
329  /// constant.
330  llvm::Constant *EmitConstantExpr(const Expr *E, QualType DestType,
331                                   CodeGenFunction *CGF = 0);
332
333  /// EmitNullConstant - Return the result of value-initializing the given
334  /// type, i.e. a null expression of the given type.  This is usually,
335  /// but not always, an LLVM null constant.
336  llvm::Constant *EmitNullConstant(QualType T);
337
338  llvm::Constant *EmitAnnotateAttr(llvm::GlobalValue *GV,
339                                   const AnnotateAttr *AA, unsigned LineNo);
340
341  llvm::Constant *EmitPointerToDataMember(const FieldDecl *FD);
342
343  /// ErrorUnsupported - Print out an error that codegen doesn't support the
344  /// specified stmt yet.
345  /// \param OmitOnError - If true, then this error should only be emitted if no
346  /// other errors have been reported.
347  void ErrorUnsupported(const Stmt *S, const char *Type,
348                        bool OmitOnError=false);
349
350  /// ErrorUnsupported - Print out an error that codegen doesn't support the
351  /// specified decl yet.
352  /// \param OmitOnError - If true, then this error should only be emitted if no
353  /// other errors have been reported.
354  void ErrorUnsupported(const Decl *D, const char *Type,
355                        bool OmitOnError=false);
356
357  /// SetInternalFunctionAttributes - Set the attributes on the LLVM
358  /// function for the given decl and function info. This applies
359  /// attributes necessary for handling the ABI as well as user
360  /// specified attributes like section.
361  void SetInternalFunctionAttributes(const Decl *D, llvm::Function *F,
362                                     const CGFunctionInfo &FI);
363
364  /// SetLLVMFunctionAttributes - Set the LLVM function attributes
365  /// (sext, zext, etc).
366  void SetLLVMFunctionAttributes(const Decl *D,
367                                 const CGFunctionInfo &Info,
368                                 llvm::Function *F);
369
370  /// SetLLVMFunctionAttributesForDefinition - Set the LLVM function attributes
371  /// which only apply to a function definintion.
372  void SetLLVMFunctionAttributesForDefinition(const Decl *D, llvm::Function *F);
373
374  /// ReturnTypeUsesSret - Return true iff the given type uses 'sret' when used
375  /// as a return type.
376  bool ReturnTypeUsesSret(const CGFunctionInfo &FI);
377
378  /// ConstructAttributeList - Get the LLVM attributes and calling convention to
379  /// use for a particular function type.
380  ///
381  /// \param Info - The function type information.
382  /// \param TargetDecl - The decl these attributes are being constructed
383  /// for. If supplied the attributes applied to this decl may contribute to the
384  /// function attributes and calling convention.
385  /// \param PAL [out] - On return, the attribute list to use.
386  /// \param CallingConv [out] - On return, the LLVM calling convention to use.
387  void ConstructAttributeList(const CGFunctionInfo &Info,
388                              const Decl *TargetDecl,
389                              AttributeListType &PAL,
390                              unsigned &CallingConv);
391
392  void getMangledName(MangleBuffer &Buffer, GlobalDecl D);
393  void getMangledName(MangleBuffer &Buffer, const NamedDecl *ND);
394  void getMangledCXXCtorName(MangleBuffer &Buffer,
395                             const CXXConstructorDecl *D,
396                             CXXCtorType Type);
397  void getMangledCXXDtorName(MangleBuffer &Buffer,
398                             const CXXDestructorDecl *D,
399                             CXXDtorType Type);
400
401  void EmitTentativeDefinition(const VarDecl *D);
402
403  enum GVALinkage {
404    GVA_Internal,
405    GVA_C99Inline,
406    GVA_CXXInline,
407    GVA_StrongExternal,
408    GVA_TemplateInstantiation,
409    GVA_ExplicitTemplateInstantiation
410  };
411
412  llvm::GlobalVariable::LinkageTypes
413  getFunctionLinkage(const FunctionDecl *FD);
414
415  /// getVtableLinkage - Return the appropriate linkage for the vtable, VTT,
416  /// and type information of the given class.
417  static llvm::GlobalVariable::LinkageTypes
418  getVtableLinkage(const CXXRecordDecl *RD);
419
420  /// GetTargetTypeStoreSize - Return the store size, in character units, of
421  /// the given LLVM type.
422  CharUnits GetTargetTypeStoreSize(const llvm::Type *Ty) const;
423
424  std::vector<const CXXRecordDecl*> DeferredVtables;
425
426private:
427  llvm::GlobalValue *GetGlobalValue(llvm::StringRef Ref);
428
429  llvm::Constant *GetOrCreateLLVMFunction(llvm::StringRef MangledName,
430                                          const llvm::Type *Ty,
431                                          GlobalDecl D);
432  llvm::Constant *GetOrCreateLLVMGlobal(llvm::StringRef MangledName,
433                                        const llvm::PointerType *PTy,
434                                        const VarDecl *D);
435
436  /// SetCommonAttributes - Set attributes which are common to any
437  /// form of a global definition (alias, Objective-C method,
438  /// function, global variable).
439  ///
440  /// NOTE: This should only be called for definitions.
441  void SetCommonAttributes(const Decl *D, llvm::GlobalValue *GV);
442
443  /// SetFunctionDefinitionAttributes - Set attributes for a global definition.
444  void SetFunctionDefinitionAttributes(const FunctionDecl *D,
445                                       llvm::GlobalValue *GV);
446
447  /// SetFunctionAttributes - Set function attributes for a function
448  /// declaration.
449  void SetFunctionAttributes(GlobalDecl GD,
450                             llvm::Function *F,
451                             bool IsIncompleteFunction);
452
453  /// EmitGlobal - Emit code for a singal global function or var decl. Forward
454  /// declarations are emitted lazily.
455  void EmitGlobal(GlobalDecl D);
456
457  void EmitGlobalDefinition(GlobalDecl D);
458
459  void EmitGlobalFunctionDefinition(GlobalDecl GD);
460  void EmitGlobalVarDefinition(const VarDecl *D);
461  void EmitAliasDefinition(GlobalDecl GD);
462  void EmitObjCPropertyImplementations(const ObjCImplementationDecl *D);
463
464  // C++ related functions.
465
466  bool TryEmitDefinitionAsAlias(GlobalDecl Alias, GlobalDecl Target);
467  bool TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D);
468
469  void EmitNamespace(const NamespaceDecl *D);
470  void EmitLinkageSpec(const LinkageSpecDecl *D);
471
472  /// EmitCXXConstructors - Emit constructors (base, complete) from a
473  /// C++ constructor Decl.
474  void EmitCXXConstructors(const CXXConstructorDecl *D);
475
476  /// EmitCXXConstructor - Emit a single constructor with the given type from
477  /// a C++ constructor Decl.
478  void EmitCXXConstructor(const CXXConstructorDecl *D, CXXCtorType Type);
479
480  /// EmitCXXDestructors - Emit destructors (base, complete) from a
481  /// C++ destructor Decl.
482  void EmitCXXDestructors(const CXXDestructorDecl *D);
483
484  /// EmitCXXDestructor - Emit a single destructor with the given type from
485  /// a C++ destructor Decl.
486  void EmitCXXDestructor(const CXXDestructorDecl *D, CXXDtorType Type);
487
488  /// EmitCXXGlobalInitFunc - Emit the function that initializes C++ globals.
489  void EmitCXXGlobalInitFunc();
490
491  /// EmitCXXGlobalDtorFunc - Emit the function that destroys C++ globals.
492  void EmitCXXGlobalDtorFunc();
493
494  void EmitCXXGlobalVarDeclInitFunc(const VarDecl *D);
495
496  // FIXME: Hardcoding priority here is gross.
497  void AddGlobalCtor(llvm::Function *Ctor, int Priority=65535);
498  void AddGlobalDtor(llvm::Function *Dtor, int Priority=65535);
499
500  /// EmitCtorList - Generates a global array of functions and priorities using
501  /// the given list and name. This array will have appending linkage and is
502  /// suitable for use as a LLVM constructor or destructor array.
503  void EmitCtorList(const CtorList &Fns, const char *GlobalName);
504
505  void EmitAnnotations(void);
506
507  /// EmitFundamentalRTTIDescriptor - Emit the RTTI descriptors for the
508  /// given type.
509  void EmitFundamentalRTTIDescriptor(QualType Type);
510
511  /// EmitFundamentalRTTIDescriptors - Emit the RTTI descriptors for the
512  /// builtin types.
513  void EmitFundamentalRTTIDescriptors();
514
515  /// EmitDeferred - Emit any needed decls for which code generation
516  /// was deferred.
517  void EmitDeferred(void);
518
519  /// EmitLLVMUsed - Emit the llvm.used metadata used to force
520  /// references to global which may otherwise be optimized out.
521  void EmitLLVMUsed(void);
522
523  /// MayDeferGeneration - Determine if the given decl can be emitted
524  /// lazily; this is only relevant for definitions. The given decl
525  /// must be either a function or var decl.
526  bool MayDeferGeneration(const ValueDecl *D);
527};
528}  // end namespace CodeGen
529}  // end namespace clang
530
531#endif
532