CGObjCRuntime.h revision 302408 
1//===----- CGObjCRuntime.h - Interface to ObjC Runtimes ---------*- 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 provides an abstract class for Objective-C code generation.  Concrete
11// subclasses of this implement code generation for specific Objective-C
12// runtime libraries.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H
17#define LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H
18#include "CGBuilder.h"
19#include "CGCall.h"
20#include "CGValue.h"
21#include "clang/AST/DeclObjC.h"
22#include "clang/Basic/IdentifierTable.h" // Selector
23
24namespace llvm {
25  class Constant;
26  class Function;
27  class Module;
28  class StructLayout;
29  class StructType;
30  class Type;
31  class Value;
32}
33
34namespace clang {
35namespace CodeGen {
36  class CodeGenFunction;
37}
38
39  class FieldDecl;
40  class ObjCAtTryStmt;
41  class ObjCAtThrowStmt;
42  class ObjCAtSynchronizedStmt;
43  class ObjCContainerDecl;
44  class ObjCCategoryImplDecl;
45  class ObjCImplementationDecl;
46  class ObjCInterfaceDecl;
47  class ObjCMessageExpr;
48  class ObjCMethodDecl;
49  class ObjCProtocolDecl;
50  class Selector;
51  class ObjCIvarDecl;
52  class ObjCStringLiteral;
53  class BlockDeclRefExpr;
54
55namespace CodeGen {
56  class CodeGenModule;
57  class CGBlockInfo;
58
59// FIXME: Several methods should be pure virtual but aren't to avoid the
60// partially-implemented subclass breaking.
61
62/// Implements runtime-specific code generation functions.
63class CGObjCRuntime {
64protected:
65  CodeGen::CodeGenModule &CGM;
66  CGObjCRuntime(CodeGen::CodeGenModule &CGM) : CGM(CGM) {}
67
68  // Utility functions for unified ivar access. These need to
69  // eventually be folded into other places (the structure layout
70  // code).
71
72  /// Compute an offset to the given ivar, suitable for passing to
73  /// EmitValueForIvarAtOffset.  Note that the correct handling of
74  /// bit-fields is carefully coordinated by these two, use caution!
75  ///
76  /// The latter overload is suitable for computing the offset of a
77  /// sythesized ivar.
78  uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
79                                 const ObjCInterfaceDecl *OID,
80                                 const ObjCIvarDecl *Ivar);
81  uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
82                                 const ObjCImplementationDecl *OID,
83                                 const ObjCIvarDecl *Ivar);
84
85  LValue EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
86                                  const ObjCInterfaceDecl *OID,
87                                  llvm::Value *BaseValue,
88                                  const ObjCIvarDecl *Ivar,
89                                  unsigned CVRQualifiers,
90                                  llvm::Value *Offset);
91  /// Emits a try / catch statement.  This function is intended to be called by
92  /// subclasses, and provides a generic mechanism for generating these, which
93  /// should be usable by all runtimes.  The caller must provide the functions
94  /// to call when entering and exiting a \@catch() block, and the function
95  /// used to rethrow exceptions.  If the begin and end catch functions are
96  /// NULL, then the function assumes that the EH personality function provides
97  /// the thrown object directly.
98  void EmitTryCatchStmt(CodeGenFunction &CGF,
99                        const ObjCAtTryStmt &S,
100                        llvm::Constant *beginCatchFn,
101                        llvm::Constant *endCatchFn,
102                        llvm::Constant *exceptionRethrowFn);
103
104  void EmitInitOfCatchParam(CodeGenFunction &CGF, llvm::Value *exn,
105                            const VarDecl *paramDecl);
106
107  /// Emits an \@synchronize() statement, using the \p syncEnterFn and
108  /// \p syncExitFn arguments as the functions called to lock and unlock
109  /// the object.  This function can be called by subclasses that use
110  /// zero-cost exception handling.
111  void EmitAtSynchronizedStmt(CodeGenFunction &CGF,
112                            const ObjCAtSynchronizedStmt &S,
113                            llvm::Function *syncEnterFn,
114                            llvm::Function *syncExitFn);
115
116public:
117  virtual ~CGObjCRuntime();
118
119  /// Generate the function required to register all Objective-C components in
120  /// this compilation unit with the runtime library.
121  virtual llvm::Function *ModuleInitFunction() = 0;
122
123  /// Get a selector for the specified name and type values.
124  /// The result should have the LLVM type for ASTContext::getObjCSelType().
125  virtual llvm::Value *GetSelector(CodeGenFunction &CGF, Selector Sel) = 0;
126
127  /// Get the address of a selector for the specified name and type values.
128  /// This is a rarely-used language extension, but sadly it exists.
129  ///
130  /// The result should have the LLVM type for a pointer to
131  /// ASTContext::getObjCSelType().
132  virtual Address GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) = 0;
133
134  /// Get a typed selector.
135  virtual llvm::Value *GetSelector(CodeGenFunction &CGF,
136                                   const ObjCMethodDecl *Method) = 0;
137
138  /// Get the type constant to catch for the given ObjC pointer type.
139  /// This is used externally to implement catching ObjC types in C++.
140  /// Runtimes which don't support this should add the appropriate
141  /// error to Sema.
142  virtual llvm::Constant *GetEHType(QualType T) = 0;
143
144  /// Generate a constant string object.
145  virtual ConstantAddress GenerateConstantString(const StringLiteral *) = 0;
146
147  /// Generate a category.  A category contains a list of methods (and
148  /// accompanying metadata) and a list of protocols.
149  virtual void GenerateCategory(const ObjCCategoryImplDecl *OCD) = 0;
150
151  /// Generate a class structure for this class.
152  virtual void GenerateClass(const ObjCImplementationDecl *OID) = 0;
153
154  /// Register an class alias.
155  virtual void RegisterAlias(const ObjCCompatibleAliasDecl *OAD) = 0;
156
157  /// Generate an Objective-C message send operation.
158  ///
159  /// \param Method - The method being called, this may be null if synthesizing
160  /// a property setter or getter.
161  virtual CodeGen::RValue
162  GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
163                      ReturnValueSlot ReturnSlot,
164                      QualType ResultType,
165                      Selector Sel,
166                      llvm::Value *Receiver,
167                      const CallArgList &CallArgs,
168                      const ObjCInterfaceDecl *Class = nullptr,
169                      const ObjCMethodDecl *Method = nullptr) = 0;
170
171  /// Generate an Objective-C message send operation to the super
172  /// class initiated in a method for Class and with the given Self
173  /// object.
174  ///
175  /// \param Method - The method being called, this may be null if synthesizing
176  /// a property setter or getter.
177  virtual CodeGen::RValue
178  GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
179                           ReturnValueSlot ReturnSlot,
180                           QualType ResultType,
181                           Selector Sel,
182                           const ObjCInterfaceDecl *Class,
183                           bool isCategoryImpl,
184                           llvm::Value *Self,
185                           bool IsClassMessage,
186                           const CallArgList &CallArgs,
187                           const ObjCMethodDecl *Method = nullptr) = 0;
188
189  /// Emit the code to return the named protocol as an object, as in a
190  /// \@protocol expression.
191  virtual llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
192                                           const ObjCProtocolDecl *OPD) = 0;
193
194  /// Generate the named protocol.  Protocols contain method metadata but no
195  /// implementations.
196  virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 0;
197
198  /// Generate a function preamble for a method with the specified
199  /// types.
200
201  // FIXME: Current this just generates the Function definition, but really this
202  // should also be generating the loads of the parameters, as the runtime
203  // should have full control over how parameters are passed.
204  virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
205                                         const ObjCContainerDecl *CD) = 0;
206
207  /// Return the runtime function for getting properties.
208  virtual llvm::Constant *GetPropertyGetFunction() = 0;
209
210  /// Return the runtime function for setting properties.
211  virtual llvm::Constant *GetPropertySetFunction() = 0;
212
213  /// Return the runtime function for optimized setting properties.
214  virtual llvm::Constant *GetOptimizedPropertySetFunction(bool atomic,
215                                                          bool copy) = 0;
216
217  // API for atomic copying of qualified aggregates in getter.
218  virtual llvm::Constant *GetGetStructFunction() = 0;
219  // API for atomic copying of qualified aggregates in setter.
220  virtual llvm::Constant *GetSetStructFunction() = 0;
221  /// API for atomic copying of qualified aggregates with non-trivial copy
222  /// assignment (c++) in setter.
223  virtual llvm::Constant *GetCppAtomicObjectSetFunction() = 0;
224  /// API for atomic copying of qualified aggregates with non-trivial copy
225  /// assignment (c++) in getter.
226  virtual llvm::Constant *GetCppAtomicObjectGetFunction() = 0;
227
228  /// GetClass - Return a reference to the class for the given
229  /// interface decl.
230  virtual llvm::Value *GetClass(CodeGenFunction &CGF,
231                                const ObjCInterfaceDecl *OID) = 0;
232
233
234  virtual llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) {
235    llvm_unreachable("autoreleasepool unsupported in this ABI");
236  }
237
238  /// EnumerationMutationFunction - Return the function that's called by the
239  /// compiler when a mutation is detected during foreach iteration.
240  virtual llvm::Constant *EnumerationMutationFunction() = 0;
241
242  virtual void EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
243                                    const ObjCAtSynchronizedStmt &S) = 0;
244  virtual void EmitTryStmt(CodeGen::CodeGenFunction &CGF,
245                           const ObjCAtTryStmt &S) = 0;
246  virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
247                             const ObjCAtThrowStmt &S,
248                             bool ClearInsertionPoint=true) = 0;
249  virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
250                                        Address AddrWeakObj) = 0;
251  virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
252                                  llvm::Value *src, Address dest) = 0;
253  virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
254                                    llvm::Value *src, Address dest,
255                                    bool threadlocal=false) = 0;
256  virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
257                                  llvm::Value *src, Address dest,
258                                  llvm::Value *ivarOffset) = 0;
259  virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
260                                        llvm::Value *src, Address dest) = 0;
261
262  virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
263                                      QualType ObjectTy,
264                                      llvm::Value *BaseValue,
265                                      const ObjCIvarDecl *Ivar,
266                                      unsigned CVRQualifiers) = 0;
267  virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
268                                      const ObjCInterfaceDecl *Interface,
269                                      const ObjCIvarDecl *Ivar) = 0;
270  virtual void EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF,
271                                        Address DestPtr,
272                                        Address SrcPtr,
273                                        llvm::Value *Size) = 0;
274  virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
275                                  const CodeGen::CGBlockInfo &blockInfo) = 0;
276  virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
277                                  const CodeGen::CGBlockInfo &blockInfo) = 0;
278
279  /// Returns an i8* which points to the byref layout information.
280  virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM,
281                                           QualType T) = 0;
282
283  virtual llvm::GlobalVariable *GetClassGlobal(const std::string &Name,
284                                               bool Weak = false) = 0;
285
286  struct MessageSendInfo {
287    const CGFunctionInfo &CallInfo;
288    llvm::PointerType *MessengerType;
289
290    MessageSendInfo(const CGFunctionInfo &callInfo,
291                    llvm::PointerType *messengerType)
292      : CallInfo(callInfo), MessengerType(messengerType) {}
293  };
294
295  MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method,
296                                     QualType resultType,
297                                     CallArgList &callArgs);
298
299  // FIXME: This probably shouldn't be here, but the code to compute
300  // it is here.
301  unsigned ComputeBitfieldBitOffset(CodeGen::CodeGenModule &CGM,
302                                    const ObjCInterfaceDecl *ID,
303                                    const ObjCIvarDecl *Ivar);
304};
305
306/// Creates an instance of an Objective-C runtime class.
307//TODO: This should include some way of selecting which runtime to target.
308CGObjCRuntime *CreateGNUObjCRuntime(CodeGenModule &CGM);
309CGObjCRuntime *CreateMacObjCRuntime(CodeGenModule &CGM);
310}
311}
312#endif
313