clang  10.0.0svn
CGBlocks.h
Go to the documentation of this file.
1 //===-- CGBlocks.h - state for LLVM CodeGen for blocks ----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This is the internal state used for llvm translation for block literals.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_LIB_CODEGEN_CGBLOCKS_H
14 #define LLVM_CLANG_LIB_CODEGEN_CGBLOCKS_H
15 
16 #include "CGBuilder.h"
17 #include "CGCall.h"
18 #include "CGValue.h"
19 #include "CodeGenFunction.h"
20 #include "CodeGenTypes.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 #include "clang/AST/Type.h"
26 #include "clang/Basic/TargetInfo.h"
27 
28 namespace llvm {
29 class Constant;
30 class Function;
31 class GlobalValue;
32 class DataLayout;
33 class FunctionType;
34 class PointerType;
35 class Value;
36 class LLVMContext;
37 }
38 
39 namespace clang {
40 namespace CodeGen {
41 
42 class CGBlockInfo;
43 
44 // Flags stored in __block variables.
46  BLOCK_BYREF_HAS_COPY_DISPOSE = (1 << 25), // compiler
47  BLOCK_BYREF_LAYOUT_MASK = (0xF << 28), // compiler
53 };
54 
56  BLOCK_IS_NOESCAPE = (1 << 23),
58  BLOCK_HAS_CXX_OBJ = (1 << 26),
59  BLOCK_IS_GLOBAL = (1 << 28),
60  BLOCK_USE_STRET = (1 << 29),
61  BLOCK_HAS_SIGNATURE = (1 << 30),
63 };
64 class BlockFlags {
65  uint32_t flags;
66 
67 public:
68  BlockFlags(uint32_t flags) : flags(flags) {}
69  BlockFlags() : flags(0) {}
70  BlockFlags(BlockLiteralFlags flag) : flags(flag) {}
71  BlockFlags(BlockByrefFlags flag) : flags(flag) {}
72 
73  uint32_t getBitMask() const { return flags; }
74  bool empty() const { return flags == 0; }
75 
77  return BlockFlags(l.flags | r.flags);
78  }
80  l.flags |= r.flags;
81  return l;
82  }
83  friend bool operator&(BlockFlags l, BlockFlags r) {
84  return (l.flags & r.flags);
85  }
87  return (flags == r.flags);
88  }
89 };
91  return BlockFlags(l) | BlockFlags(r);
92 }
93 
95  BLOCK_FIELD_IS_OBJECT = 0x03, /* id, NSObject, __attribute__((NSObject)),
96  block, ... */
97  BLOCK_FIELD_IS_BLOCK = 0x07, /* a block variable */
98 
99  BLOCK_FIELD_IS_BYREF = 0x08, /* the on stack structure holding the __block
100  variable */
101  BLOCK_FIELD_IS_WEAK = 0x10, /* declared __weak, only used in byref copy
102  helpers */
103  BLOCK_FIELD_IS_ARC = 0x40, /* field has ARC-specific semantics */
104  BLOCK_BYREF_CALLER = 128, /* called from __block (byref) copy/dispose
105  support routines */
107 };
108 
110  uint32_t flags;
111 
112  BlockFieldFlags(uint32_t flags) : flags(flags) {}
113 public:
114  BlockFieldFlags() : flags(0) {}
115  BlockFieldFlags(BlockFieldFlag_t flag) : flags(flag) {}
116 
117  uint32_t getBitMask() const { return flags; }
118  bool empty() const { return flags == 0; }
119 
120  /// Answers whether the flags indicate that this field is an object
121  /// or block pointer that requires _Block_object_assign/dispose.
122  bool isSpecialPointer() const { return flags & BLOCK_FIELD_IS_OBJECT; }
123 
125  return BlockFieldFlags(l.flags | r.flags);
126  }
128  l.flags |= r.flags;
129  return l;
130  }
132  return (l.flags & r.flags);
133  }
134  bool operator==(BlockFieldFlags Other) const {
135  return flags == Other.flags;
136  }
137 };
139  return BlockFieldFlags(l) | BlockFieldFlags(r);
140 }
141 
142 /// Information about the layout of a __block variable.
144 public:
145  llvm::StructType *Type;
146  unsigned FieldIndex;
149 };
150 
151 /// CGBlockInfo - Information to generate a block literal.
152 class CGBlockInfo {
153 public:
154  /// Name - The name of the block, kindof.
155  StringRef Name;
156 
157  /// The field index of 'this' within the block, if there is one.
158  unsigned CXXThisIndex;
159 
160  class Capture {
161  uintptr_t Data;
164 
165  /// Type of the capture field. Normally, this is identical to the type of
166  /// the capture's VarDecl, but can be different if there is an enclosing
167  /// lambda.
168  QualType FieldType;
169 
170  public:
171  bool isIndex() const { return (Data & 1) != 0; }
172  bool isConstant() const { return !isIndex(); }
173 
174  unsigned getIndex() const {
175  assert(isIndex());
176  return Data >> 1;
177  }
179  assert(isIndex());
180  return CharUnits::fromQuantity(Offset);
181  }
183  assert(isIndex());
184  return Cleanup;
185  }
187  assert(isIndex());
188  Cleanup = cleanup;
189  }
190 
192  assert(isConstant());
193  return reinterpret_cast<llvm::Value*>(Data);
194  }
195 
196  QualType fieldType() const {
197  return FieldType;
198  }
199 
200  static Capture makeIndex(unsigned index, CharUnits offset,
201  QualType FieldType) {
202  Capture v;
203  v.Data = (index << 1) | 1;
204  v.Offset = offset.getQuantity();
205  v.FieldType = FieldType;
206  return v;
207  }
208 
210  Capture v;
211  v.Data = reinterpret_cast<uintptr_t>(value);
212  return v;
213  }
214  };
215 
216  /// CanBeGlobal - True if the block can be global, i.e. it has
217  /// no non-constant captures.
218  bool CanBeGlobal : 1;
219 
220  /// True if the block has captures that would necessitate custom copy or
221  /// dispose helper functions if the block were escaping.
223 
224  /// HasCXXObject - True if the block's custom copy/dispose functions
225  /// need to be run even in GC mode.
226  bool HasCXXObject : 1;
227 
228  /// UsesStret : True if the block uses an stret return. Mutable
229  /// because it gets set later in the block-creation process.
230  mutable bool UsesStret : 1;
231 
232  /// HasCapturedVariableLayout : True if block has captured variables
233  /// and their layout meta-data has been generated.
235 
236  /// Indicates whether an object of a non-external C++ class is captured. This
237  /// bit is used to determine the linkage of the block copy/destroy helper
238  /// functions.
240 
241  /// The mapping of allocated indexes within the block.
242  llvm::DenseMap<const VarDecl*, Capture> Captures;
243 
245  llvm::StructType *StructureType;
246  const BlockDecl *Block;
251 
252  // Offset of the gap caused by block header having a smaller
253  // alignment than the alignment of the block descriptor. This
254  // is the gap offset before the first capturued field.
256  // Gap size caused by aligning first field after block header.
257  // This could be zero if no forced alignment is required.
259 
260  /// An instruction which dominates the full-expression that the
261  /// block is inside.
262  llvm::Instruction *DominatingIP;
263 
264  /// The next block in the block-info chain. Invalid if this block
265  /// info is not part of the CGF's block-info chain, which is true
266  /// if it corresponds to a global block or a block whose expression
267  /// has been encountered.
269 
270  const Capture &getCapture(const VarDecl *var) const {
271  return const_cast<CGBlockInfo*>(this)->getCapture(var);
272  }
273  Capture &getCapture(const VarDecl *var) {
274  llvm::DenseMap<const VarDecl*, Capture>::iterator
275  it = Captures.find(var);
276  assert(it != Captures.end() && "no entry for variable!");
277  return it->second;
278  }
279 
280  const BlockDecl *getBlockDecl() const { return Block; }
281  const BlockExpr *getBlockExpr() const {
282  assert(BlockExpression);
283  assert(BlockExpression->getBlockDecl() == Block);
284  return BlockExpression;
285  }
286 
287  CGBlockInfo(const BlockDecl *blockDecl, StringRef Name);
288 
289  // Indicates whether the block needs a custom copy or dispose function.
290  bool needsCopyDisposeHelpers() const {
291  return NeedsCopyDispose && !Block->doesNotEscape();
292  }
293 };
294 
295 } // end namespace CodeGen
296 } // end namespace clang
297 
298 #endif
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5565
Information about the layout of a __block variable.
Definition: CGBlocks.h:143
const Capture & getCapture(const VarDecl *var) const
Definition: CGBlocks.h:270
int64_t QuantityType
Definition: CharUnits.h:40
CharUnits BlockHeaderForcedGapOffset
Definition: CGBlocks.h:255
A (possibly-)qualified type.
Definition: Type.h:643
Capture & getCapture(const VarDecl *var)
Definition: CGBlocks.h:273
Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be placed into a PointerUnion...
Definition: Dominators.h:30
tooling::Replacements cleanup(const FormatStyle &Style, StringRef Code, ArrayRef< tooling::Range > Ranges, StringRef FileName="<stdin>")
Clean up any erroneous/redundant code in the given Ranges in Code.
Definition: Format.cpp:2454
C Language Family Type Representation.
friend BlockFieldFlags operator|(BlockFieldFlags l, BlockFieldFlags r)
Definition: CGBlocks.h:124
bool operator==(BlockFlags r)
Definition: CGBlocks.h:86
constexpr XRayInstrMask Function
Definition: XRayInstr.h:38
BlockFlags(uint32_t flags)
Definition: CGBlocks.h:68
Represents a variable declaration or definition.
Definition: Decl.h:827
EHScopeStack::stable_iterator getCleanup() const
Definition: CGBlocks.h:182
Defines the clang::Expr interface and subclasses for C++ expressions.
const BlockDecl * Block
Definition: CGBlocks.h:246
bool doesNotEscape() const
Definition: Decl.h:4102
bool HasCapturedVariableLayout
HasCapturedVariableLayout : True if block has captured variables and their layout meta-data has been ...
Definition: CGBlocks.h:234
BlockFlags(BlockByrefFlags flag)
Definition: CGBlocks.h:71
BlockFieldFlags operator|(BlockFieldFlag_t l, BlockFieldFlag_t r)
Definition: CGBlocks.h:138
BlockFieldFlags(BlockFieldFlag_t flag)
Definition: CGBlocks.h:115
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
const BlockDecl * getBlockDecl() const
Definition: CGBlocks.h:280
bool HasCXXObject
HasCXXObject - True if the block&#39;s custom copy/dispose functions need to be run even in GC mode...
Definition: CGBlocks.h:226
uint32_t getBitMask() const
Definition: CGBlocks.h:117
static Capture makeConstant(llvm::Value *value)
Definition: CGBlocks.h:209
friend BlockFieldFlags & operator|=(BlockFieldFlags &l, BlockFieldFlags r)
Definition: CGBlocks.h:127
StringRef Name
Name - The name of the block, kindof.
Definition: CGBlocks.h:155
bool NeedsCopyDispose
True if the block has captures that would necessitate custom copy or dispose helper functions if the ...
Definition: CGBlocks.h:222
const BlockExpr * BlockExpression
Definition: CGBlocks.h:247
uint32_t getBitMask() const
Definition: CGBlocks.h:73
CGBlockInfo - Information to generate a block literal.
Definition: CGBlocks.h:152
bool CanBeGlobal
CanBeGlobal - True if the block can be global, i.e.
Definition: CGBlocks.h:218
QuantityType getQuantity() const
getQuantity - Get the raw integer representation of this quantity.
Definition: CharUnits.h:179
BlockFlags(BlockLiteralFlags flag)
Definition: CGBlocks.h:70
unsigned Offset
Definition: Format.cpp:1809
CGBlockInfo * NextBlockInfo
The next block in the block-info chain.
Definition: CGBlocks.h:268
DiagnosticLevelMask operator &(DiagnosticLevelMask LHS, DiagnosticLevelMask RHS)
Represents a block literal declaration, which is like an unnamed FunctionDecl.
Definition: Decl.h:3951
__UINTPTR_TYPE__ uintptr_t
An unsigned integer type with the property that any valid pointer to void can be converted to this ty...
Definition: opencl-c-base.h:62
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5551
friend BlockFlags operator|(BlockFlags l, BlockFlags r)
Definition: CGBlocks.h:76
bool needsCopyDisposeHelpers() const
Definition: CGBlocks.h:290
static Capture makeIndex(unsigned index, CharUnits offset, QualType FieldType)
Definition: CGBlocks.h:200
do v
Definition: arm_acle.h:64
bool UsesStret
UsesStret : True if the block uses an stret return.
Definition: CGBlocks.h:230
A saved depth on the scope stack.
Definition: EHScopeStack.h:106
llvm::StructType * StructureType
Definition: CGBlocks.h:245
bool CapturesNonExternalType
Indicates whether an object of a non-external C++ class is captured.
Definition: CGBlocks.h:239
llvm::DenseMap< const VarDecl *, Capture > Captures
The mapping of allocated indexes within the block.
Definition: CGBlocks.h:242
An aligned address.
Definition: Address.h:24
llvm::Value * getConstant() const
Definition: CGBlocks.h:191
const BlockExpr * getBlockExpr() const
Definition: CGBlocks.h:281
unsigned CXXThisIndex
The field index of &#39;this&#39; within the block, if there is one.
Definition: CGBlocks.h:158
Dataflow Directional Tag Classes.
bool isSpecialPointer() const
Answers whether the flags indicate that this field is an object or block pointer that requires _Block...
Definition: CGBlocks.h:122
friend BlockFlags & operator|=(BlockFlags &l, BlockFlags r)
Definition: CGBlocks.h:79
llvm::StructType * Type
Definition: CGBlocks.h:145
CharUnits BlockHeaderForcedGapSize
Definition: CGBlocks.h:258
bool operator==(BlockFieldFlags Other) const
Definition: CGBlocks.h:134
Defines the clang::TargetInfo interface.
const internal::VariadicDynCastAllOfMatcher< Decl, BlockDecl > blockDecl
Matches block declarations.
llvm::Instruction * DominatingIP
An instruction which dominates the full-expression that the block is inside.
Definition: CGBlocks.h:262
void setCleanup(EHScopeStack::stable_iterator cleanup)
Definition: CGBlocks.h:186