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 "CGBuilder.h"
18#include "CGCall.h"
19#include "CGValue.h"
20#include "CodeGenFunction.h"
21#include "CodeGenTypes.h"
22#include "clang/AST/CharUnits.h"
23#include "clang/AST/Expr.h"
24#include "clang/AST/ExprCXX.h"
25#include "clang/AST/ExprObjC.h"
26#include "clang/AST/Type.h"
27#include "clang/Basic/TargetInfo.h"
28#include "llvm/IR/Module.h"
29
30namespace llvm {
31class Module;
32class Constant;
33class Function;
34class GlobalValue;
35class DataLayout;
36class FunctionType;
37class PointerType;
38class Value;
39class LLVMContext;
40}
41
42namespace clang {
43
44namespace CodeGen {
45
46class CodeGenModule;
47class CGBlockInfo;
48
49// Flags stored in __block variables.
50enum BlockByrefFlags {
51  BLOCK_BYREF_HAS_COPY_DISPOSE         = (1   << 25), // compiler
52  BLOCK_BYREF_LAYOUT_MASK              = (0xF << 28), // compiler
53  BLOCK_BYREF_LAYOUT_EXTENDED          = (1   << 28),
54  BLOCK_BYREF_LAYOUT_NON_OBJECT        = (2   << 28),
55  BLOCK_BYREF_LAYOUT_STRONG            = (3   << 28),
56  BLOCK_BYREF_LAYOUT_WEAK              = (4   << 28),
57  BLOCK_BYREF_LAYOUT_UNRETAINED        = (5   << 28)
58};
59
60enum BlockLiteralFlags {
61  BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
62  BLOCK_HAS_CXX_OBJ =       (1 << 26),
63  BLOCK_IS_GLOBAL =         (1 << 28),
64  BLOCK_USE_STRET =         (1 << 29),
65  BLOCK_HAS_SIGNATURE  =    (1 << 30),
66  BLOCK_HAS_EXTENDED_LAYOUT = (1 << 31)
67};
68class BlockFlags {
69  uint32_t flags;
70
71public:
72  BlockFlags(uint32_t flags) : flags(flags) {}
73  BlockFlags() : flags(0) {}
74  BlockFlags(BlockLiteralFlags flag) : flags(flag) {}
75  BlockFlags(BlockByrefFlags flag) : flags(flag) {}
76
77  uint32_t getBitMask() const { return flags; }
78  bool empty() const { return flags == 0; }
79
80  friend BlockFlags operator|(BlockFlags l, BlockFlags r) {
81    return BlockFlags(l.flags | r.flags);
82  }
83  friend BlockFlags &operator|=(BlockFlags &l, BlockFlags r) {
84    l.flags |= r.flags;
85    return l;
86  }
87  friend bool operator&(BlockFlags l, BlockFlags r) {
88    return (l.flags & r.flags);
89  }
90  bool operator==(BlockFlags r) {
91    return (flags == r.flags);
92  }
93};
94inline BlockFlags operator|(BlockLiteralFlags l, BlockLiteralFlags r) {
95  return BlockFlags(l) | BlockFlags(r);
96}
97
98enum BlockFieldFlag_t {
99  BLOCK_FIELD_IS_OBJECT   = 0x03,  /* id, NSObject, __attribute__((NSObject)),
100                                    block, ... */
101  BLOCK_FIELD_IS_BLOCK    = 0x07,  /* a block variable */
102
103  BLOCK_FIELD_IS_BYREF    = 0x08,  /* the on stack structure holding the __block
104                                    variable */
105  BLOCK_FIELD_IS_WEAK     = 0x10,  /* declared __weak, only used in byref copy
106                                    helpers */
107  BLOCK_FIELD_IS_ARC      = 0x40,  /* field has ARC-specific semantics */
108  BLOCK_BYREF_CALLER      = 128,   /* called from __block (byref) copy/dispose
109                                      support routines */
110  BLOCK_BYREF_CURRENT_MAX = 256
111};
112
113class BlockFieldFlags {
114  uint32_t flags;
115
116  BlockFieldFlags(uint32_t flags) : flags(flags) {}
117public:
118  BlockFieldFlags() : flags(0) {}
119  BlockFieldFlags(BlockFieldFlag_t flag) : flags(flag) {}
120
121  uint32_t getBitMask() const { return flags; }
122  bool empty() const { return flags == 0; }
123
124  /// Answers whether the flags indicate that this field is an object
125  /// or block pointer that requires _Block_object_assign/dispose.
126  bool isSpecialPointer() const { return flags & BLOCK_FIELD_IS_OBJECT; }
127
128  friend BlockFieldFlags operator|(BlockFieldFlags l, BlockFieldFlags r) {
129    return BlockFieldFlags(l.flags | r.flags);
130  }
131  friend BlockFieldFlags &operator|=(BlockFieldFlags &l, BlockFieldFlags r) {
132    l.flags |= r.flags;
133    return l;
134  }
135  friend bool operator&(BlockFieldFlags l, BlockFieldFlags r) {
136    return (l.flags & r.flags);
137  }
138};
139inline BlockFieldFlags operator|(BlockFieldFlag_t l, BlockFieldFlag_t r) {
140  return BlockFieldFlags(l) | BlockFieldFlags(r);
141}
142
143/// CGBlockInfo - Information to generate a block literal.
144class CGBlockInfo {
145public:
146  /// Name - The name of the block, kindof.
147  StringRef Name;
148
149  /// The field index of 'this' within the block, if there is one.
150  unsigned CXXThisIndex;
151
152  class Capture {
153    uintptr_t Data;
154    EHScopeStack::stable_iterator Cleanup;
155
156  public:
157    bool isIndex() const { return (Data & 1) != 0; }
158    bool isConstant() const { return !isIndex(); }
159    unsigned getIndex() const { assert(isIndex()); return Data >> 1; }
160    llvm::Value *getConstant() const {
161      assert(isConstant());
162      return reinterpret_cast<llvm::Value*>(Data);
163    }
164    EHScopeStack::stable_iterator getCleanup() const {
165      assert(isIndex());
166      return Cleanup;
167    }
168    void setCleanup(EHScopeStack::stable_iterator cleanup) {
169      assert(isIndex());
170      Cleanup = cleanup;
171    }
172
173    static Capture makeIndex(unsigned index) {
174      Capture v;
175      v.Data = (index << 1) | 1;
176      return v;
177    }
178
179    static Capture makeConstant(llvm::Value *value) {
180      Capture v;
181      v.Data = reinterpret_cast<uintptr_t>(value);
182      return v;
183    }
184  };
185
186  /// CanBeGlobal - True if the block can be global, i.e. it has
187  /// no non-constant captures.
188  bool CanBeGlobal : 1;
189
190  /// True if the block needs a custom copy or dispose function.
191  bool NeedsCopyDispose : 1;
192
193  /// HasCXXObject - True if the block's custom copy/dispose functions
194  /// need to be run even in GC mode.
195  bool HasCXXObject : 1;
196
197  /// UsesStret : True if the block uses an stret return.  Mutable
198  /// because it gets set later in the block-creation process.
199  mutable bool UsesStret : 1;
200
201  /// HasCapturedVariableLayout : True if block has captured variables
202  /// and their layout meta-data has been generated.
203  bool HasCapturedVariableLayout : 1;
204
205  /// The mapping of allocated indexes within the block.
206  llvm::DenseMap<const VarDecl*, Capture> Captures;
207
208  llvm::AllocaInst *Address;
209  llvm::StructType *StructureType;
210  const BlockDecl *Block;
211  const BlockExpr *BlockExpression;
212  CharUnits BlockSize;
213  CharUnits BlockAlign;
214
215  // Offset of the gap caused by block header having a smaller
216  // alignment than the alignment of the block descriptor. This
217  // is the gap offset before the first capturued field.
218  CharUnits BlockHeaderForcedGapOffset;
219  // Gap size caused by aligning first field after block header.
220  // This could be zero if no forced alignment is required.
221  CharUnits BlockHeaderForcedGapSize;
222
223  /// An instruction which dominates the full-expression that the
224  /// block is inside.
225  llvm::Instruction *DominatingIP;
226
227  /// The next block in the block-info chain.  Invalid if this block
228  /// info is not part of the CGF's block-info chain, which is true
229  /// if it corresponds to a global block or a block whose expression
230  /// has been encountered.
231  CGBlockInfo *NextBlockInfo;
232
233  const Capture &getCapture(const VarDecl *var) const {
234    return const_cast<CGBlockInfo*>(this)->getCapture(var);
235  }
236  Capture &getCapture(const VarDecl *var) {
237    llvm::DenseMap<const VarDecl*, Capture>::iterator
238      it = Captures.find(var);
239    assert(it != Captures.end() && "no entry for variable!");
240    return it->second;
241  }
242
243  const BlockDecl *getBlockDecl() const { return Block; }
244  const BlockExpr *getBlockExpr() const {
245    assert(BlockExpression);
246    assert(BlockExpression->getBlockDecl() == Block);
247    return BlockExpression;
248  }
249
250  CGBlockInfo(const BlockDecl *blockDecl, StringRef Name);
251};
252
253}  // end namespace CodeGen
254}  // end namespace clang
255
256#endif
257