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 LLVM_CLANG_LIB_CODEGEN_CGBLOCKS_H
15#define LLVM_CLANG_LIB_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/// Information about the layout of a __block variable.
144class BlockByrefInfo {
145public:
146  llvm::StructType *Type;
147  unsigned FieldIndex;
148  CharUnits ByrefAlignment;
149  CharUnits FieldOffset;
150};
151
152/// CGBlockInfo - Information to generate a block literal.
153class CGBlockInfo {
154public:
155  /// Name - The name of the block, kindof.
156  StringRef Name;
157
158  /// The field index of 'this' within the block, if there is one.
159  unsigned CXXThisIndex;
160
161  class Capture {
162    uintptr_t Data;
163    EHScopeStack::stable_iterator Cleanup;
164    CharUnits::QuantityType Offset;
165
166  public:
167    bool isIndex() const { return (Data & 1) != 0; }
168    bool isConstant() const { return !isIndex(); }
169
170    unsigned getIndex() const {
171      assert(isIndex());
172      return Data >> 1;
173    }
174    CharUnits getOffset() const {
175      assert(isIndex());
176      return CharUnits::fromQuantity(Offset);
177    }
178    EHScopeStack::stable_iterator getCleanup() const {
179      assert(isIndex());
180      return Cleanup;
181    }
182    void setCleanup(EHScopeStack::stable_iterator cleanup) {
183      assert(isIndex());
184      Cleanup = cleanup;
185    }
186
187    llvm::Value *getConstant() const {
188      assert(isConstant());
189      return reinterpret_cast<llvm::Value*>(Data);
190    }
191
192    static Capture makeIndex(unsigned index, CharUnits offset) {
193      Capture v;
194      v.Data = (index << 1) | 1;
195      v.Offset = offset.getQuantity();
196      return v;
197    }
198
199    static Capture makeConstant(llvm::Value *value) {
200      Capture v;
201      v.Data = reinterpret_cast<uintptr_t>(value);
202      return v;
203    }
204  };
205
206  /// CanBeGlobal - True if the block can be global, i.e. it has
207  /// no non-constant captures.
208  bool CanBeGlobal : 1;
209
210  /// True if the block needs a custom copy or dispose function.
211  bool NeedsCopyDispose : 1;
212
213  /// HasCXXObject - True if the block's custom copy/dispose functions
214  /// need to be run even in GC mode.
215  bool HasCXXObject : 1;
216
217  /// UsesStret : True if the block uses an stret return.  Mutable
218  /// because it gets set later in the block-creation process.
219  mutable bool UsesStret : 1;
220
221  /// HasCapturedVariableLayout : True if block has captured variables
222  /// and their layout meta-data has been generated.
223  bool HasCapturedVariableLayout : 1;
224
225  /// The mapping of allocated indexes within the block.
226  llvm::DenseMap<const VarDecl*, Capture> Captures;
227
228  Address LocalAddress;
229  llvm::StructType *StructureType;
230  const BlockDecl *Block;
231  const BlockExpr *BlockExpression;
232  CharUnits BlockSize;
233  CharUnits BlockAlign;
234  CharUnits CXXThisOffset;
235
236  // Offset of the gap caused by block header having a smaller
237  // alignment than the alignment of the block descriptor. This
238  // is the gap offset before the first capturued field.
239  CharUnits BlockHeaderForcedGapOffset;
240  // Gap size caused by aligning first field after block header.
241  // This could be zero if no forced alignment is required.
242  CharUnits BlockHeaderForcedGapSize;
243
244  /// An instruction which dominates the full-expression that the
245  /// block is inside.
246  llvm::Instruction *DominatingIP;
247
248  /// The next block in the block-info chain.  Invalid if this block
249  /// info is not part of the CGF's block-info chain, which is true
250  /// if it corresponds to a global block or a block whose expression
251  /// has been encountered.
252  CGBlockInfo *NextBlockInfo;
253
254  const Capture &getCapture(const VarDecl *var) const {
255    return const_cast<CGBlockInfo*>(this)->getCapture(var);
256  }
257  Capture &getCapture(const VarDecl *var) {
258    llvm::DenseMap<const VarDecl*, Capture>::iterator
259      it = Captures.find(var);
260    assert(it != Captures.end() && "no entry for variable!");
261    return it->second;
262  }
263
264  const BlockDecl *getBlockDecl() const { return Block; }
265  const BlockExpr *getBlockExpr() const {
266    assert(BlockExpression);
267    assert(BlockExpression->getBlockDecl() == Block);
268    return BlockExpression;
269  }
270
271  CGBlockInfo(const BlockDecl *blockDecl, StringRef Name);
272};
273
274}  // end namespace CodeGen
275}  // end namespace clang
276
277#endif
278