CGBlocks.h revision 2acc6e3feda5e4f7d9009bdcf8b1cd777fecfe2d 
1//===-- CGBlocks.h - state for LLVM CodeGen for blocks ----------*- 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 state used for llvm translation for block literals.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef CLANG_CODEGEN_CGBLOCKS_H
15#define CLANG_CODEGEN_CGBLOCKS_H
16
17#include "CodeGenTypes.h"
18#include "clang/AST/Type.h"
19#include "llvm/Module.h"
20#include "clang/Basic/TargetInfo.h"
21#include "clang/AST/CharUnits.h"
22#include "clang/AST/Expr.h"
23#include "clang/AST/ExprCXX.h"
24#include "clang/AST/ExprObjC.h"
25
26#include "CGBuilder.h"
27#include "CGCall.h"
28#include "CGValue.h"
29
30namespace llvm {
31  class Module;
32  class Constant;
33  class Function;
34  class GlobalValue;
35  class TargetData;
36  class FunctionType;
37  class PointerType;
38  class Value;
39  class LLVMContext;
40}
41
42namespace clang {
43
44namespace CodeGen {
45
46class CodeGenModule;
47class CGBlockInfo;
48
49enum BlockFlag_t {
50  BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
51  BLOCK_HAS_CXX_OBJ =       (1 << 26),
52  BLOCK_IS_GLOBAL =         (1 << 28),
53  BLOCK_USE_STRET =         (1 << 29),
54  BLOCK_HAS_SIGNATURE  =    (1 << 30)
55};
56class BlockFlags {
57  uint32_t flags;
58
59  BlockFlags(uint32_t flags) : flags(flags) {}
60public:
61  BlockFlags() : flags(0) {}
62  BlockFlags(BlockFlag_t flag) : flags(flag) {}
63
64  uint32_t getBitMask() const { return flags; }
65  bool empty() const { return flags == 0; }
66
67  friend BlockFlags operator|(BlockFlags l, BlockFlags r) {
68    return BlockFlags(l.flags | r.flags);
69  }
70  friend BlockFlags &operator|=(BlockFlags &l, BlockFlags r) {
71    l.flags |= r.flags;
72    return l;
73  }
74  friend bool operator&(BlockFlags l, BlockFlags r) {
75    return (l.flags & r.flags);
76  }
77};
78inline BlockFlags operator|(BlockFlag_t l, BlockFlag_t r) {
79  return BlockFlags(l) | BlockFlags(r);
80}
81
82enum BlockFieldFlag_t {
83  BLOCK_FIELD_IS_OBJECT   = 0x03,  /* id, NSObject, __attribute__((NSObject)),
84                                    block, ... */
85  BLOCK_FIELD_IS_BLOCK    = 0x07,  /* a block variable */
86
87  BLOCK_FIELD_IS_BYREF    = 0x08,  /* the on stack structure holding the __block
88                                    variable */
89  BLOCK_FIELD_IS_WEAK     = 0x10,  /* declared __weak, only used in byref copy
90                                    helpers */
91  BLOCK_FIELD_IS_ARC      = 0x40,  /* field has ARC-specific semantics */
92  BLOCK_BYREF_CALLER      = 128,   /* called from __block (byref) copy/dispose
93                                      support routines */
94  BLOCK_BYREF_CURRENT_MAX = 256
95};
96
97class BlockFieldFlags {
98  uint32_t flags;
99
100  BlockFieldFlags(uint32_t flags) : flags(flags) {}
101public:
102  BlockFieldFlags() : flags(0) {}
103  BlockFieldFlags(BlockFieldFlag_t flag) : flags(flag) {}
104
105  uint32_t getBitMask() const { return flags; }
106  bool empty() const { return flags == 0; }
107
108  /// Answers whether the flags indicate that this field is an object
109  /// or block pointer that requires _Block_object_assign/dispose.
110  bool isSpecialPointer() const { return flags & BLOCK_FIELD_IS_OBJECT; }
111
112  friend BlockFieldFlags operator|(BlockFieldFlags l, BlockFieldFlags r) {
113    return BlockFieldFlags(l.flags | r.flags);
114  }
115  friend BlockFieldFlags &operator|=(BlockFieldFlags &l, BlockFieldFlags r) {
116    l.flags |= r.flags;
117    return l;
118  }
119  friend bool operator&(BlockFieldFlags l, BlockFieldFlags r) {
120    return (l.flags & r.flags);
121  }
122};
123inline BlockFieldFlags operator|(BlockFieldFlag_t l, BlockFieldFlag_t r) {
124  return BlockFieldFlags(l) | BlockFieldFlags(r);
125}
126
127/// CGBlockInfo - Information to generate a block literal.
128class CGBlockInfo {
129public:
130  /// Name - The name of the block, kindof.
131  const char *Name;
132
133  /// The field index of 'this' within the block, if there is one.
134  unsigned CXXThisIndex;
135
136  class Capture {
137    uintptr_t Data;
138
139  public:
140    bool isIndex() const { return (Data & 1) != 0; }
141    bool isConstant() const { return !isIndex(); }
142    unsigned getIndex() const { assert(isIndex()); return Data >> 1; }
143    llvm::Value *getConstant() const {
144      assert(isConstant());
145      return reinterpret_cast<llvm::Value*>(Data);
146    }
147
148    static Capture makeIndex(unsigned index) {
149      Capture v;
150      v.Data = (index << 1) | 1;
151      return v;
152    }
153
154    static Capture makeConstant(llvm::Value *value) {
155      Capture v;
156      v.Data = reinterpret_cast<uintptr_t>(value);
157      return v;
158    }
159  };
160
161  /// The mapping of allocated indexes within the block.
162  llvm::DenseMap<const VarDecl*, Capture> Captures;
163
164  /// CanBeGlobal - True if the block can be global, i.e. it has
165  /// no non-constant captures.
166  bool CanBeGlobal : 1;
167
168  /// True if the block needs a custom copy or dispose function.
169  bool NeedsCopyDispose : 1;
170
171  /// HasCXXObject - True if the block's custom copy/dispose functions
172  /// need to be run even in GC mode.
173  bool HasCXXObject : 1;
174
175  /// UsesStret : True if the block uses an stret return.  Mutable
176  /// because it gets set later in the block-creation process.
177  mutable bool UsesStret : 1;
178
179  llvm::StructType *StructureType;
180  const BlockExpr *Block;
181  CharUnits BlockSize;
182  CharUnits BlockAlign;
183
184  const Capture &getCapture(const VarDecl *var) const {
185    llvm::DenseMap<const VarDecl*, Capture>::const_iterator
186      it = Captures.find(var);
187    assert(it != Captures.end() && "no entry for variable!");
188    return it->second;
189  }
190
191  const BlockDecl *getBlockDecl() const { return Block->getBlockDecl(); }
192  const BlockExpr *getBlockExpr() const { return Block; }
193
194  CGBlockInfo(const BlockExpr *blockExpr, const char *Name);
195};
196
197}  // end namespace CodeGen
198}  // end namespace clang
199
200#endif
201