1 //===-- CGBlocks.h - state for LLVM CodeGen for blocks ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This is the internal state used for llvm translation for block literals.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_LIB_CODEGEN_CGBLOCKS_H
15 #define LLVM_CLANG_LIB_CODEGEN_CGBLOCKS_H
17 #include "CGBuilder.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"
45 // Flags stored in __block variables.
46 enum BlockByrefFlags {
47 BLOCK_BYREF_HAS_COPY_DISPOSE = (1 << 25), // compiler
48 BLOCK_BYREF_LAYOUT_MASK = (0xF << 28), // compiler
49 BLOCK_BYREF_LAYOUT_EXTENDED = (1 << 28),
50 BLOCK_BYREF_LAYOUT_NON_OBJECT = (2 << 28),
51 BLOCK_BYREF_LAYOUT_STRONG = (3 << 28),
52 BLOCK_BYREF_LAYOUT_WEAK = (4 << 28),
53 BLOCK_BYREF_LAYOUT_UNRETAINED = (5 << 28)
56 enum BlockLiteralFlags {
57 BLOCK_IS_NOESCAPE = (1 << 23),
58 BLOCK_HAS_COPY_DISPOSE = (1 << 25),
59 BLOCK_HAS_CXX_OBJ = (1 << 26),
60 BLOCK_IS_GLOBAL = (1 << 28),
61 BLOCK_USE_STRET = (1 << 29),
62 BLOCK_HAS_SIGNATURE = (1 << 30),
63 BLOCK_HAS_EXTENDED_LAYOUT = (1 << 31)
69 BlockFlags(uint32_t flags) : flags(flags) {}
70 BlockFlags() : flags(0) {}
71 BlockFlags(BlockLiteralFlags flag) : flags(flag) {}
72 BlockFlags(BlockByrefFlags flag) : flags(flag) {}
74 uint32_t getBitMask() const { return flags; }
75 bool empty() const { return flags == 0; }
77 friend BlockFlags operator|(BlockFlags l, BlockFlags r) {
78 return BlockFlags(l.flags | r.flags);
80 friend BlockFlags &operator|=(BlockFlags &l, BlockFlags r) {
84 friend bool operator&(BlockFlags l, BlockFlags r) {
85 return (l.flags & r.flags);
87 bool operator==(BlockFlags r) {
88 return (flags == r.flags);
91 inline BlockFlags operator|(BlockLiteralFlags l, BlockLiteralFlags r) {
92 return BlockFlags(l) | BlockFlags(r);
95 enum BlockFieldFlag_t {
96 BLOCK_FIELD_IS_OBJECT = 0x03, /* id, NSObject, __attribute__((NSObject)),
98 BLOCK_FIELD_IS_BLOCK = 0x07, /* a block variable */
100 BLOCK_FIELD_IS_BYREF = 0x08, /* the on stack structure holding the __block
102 BLOCK_FIELD_IS_WEAK = 0x10, /* declared __weak, only used in byref copy
104 BLOCK_FIELD_IS_ARC = 0x40, /* field has ARC-specific semantics */
105 BLOCK_BYREF_CALLER = 128, /* called from __block (byref) copy/dispose
107 BLOCK_BYREF_CURRENT_MAX = 256
110 class BlockFieldFlags {
113 BlockFieldFlags(uint32_t flags) : flags(flags) {}
115 BlockFieldFlags() : flags(0) {}
116 BlockFieldFlags(BlockFieldFlag_t flag) : flags(flag) {}
118 uint32_t getBitMask() const { return flags; }
119 bool empty() const { return flags == 0; }
121 /// Answers whether the flags indicate that this field is an object
122 /// or block pointer that requires _Block_object_assign/dispose.
123 bool isSpecialPointer() const { return flags & BLOCK_FIELD_IS_OBJECT; }
125 friend BlockFieldFlags operator|(BlockFieldFlags l, BlockFieldFlags r) {
126 return BlockFieldFlags(l.flags | r.flags);
128 friend BlockFieldFlags &operator|=(BlockFieldFlags &l, BlockFieldFlags r) {
132 friend bool operator&(BlockFieldFlags l, BlockFieldFlags r) {
133 return (l.flags & r.flags);
136 inline BlockFieldFlags operator|(BlockFieldFlag_t l, BlockFieldFlag_t r) {
137 return BlockFieldFlags(l) | BlockFieldFlags(r);
140 /// Information about the layout of a __block variable.
141 class BlockByrefInfo {
143 llvm::StructType *Type;
145 CharUnits ByrefAlignment;
146 CharUnits FieldOffset;
149 /// CGBlockInfo - Information to generate a block literal.
152 /// Name - The name of the block, kindof.
155 /// The field index of 'this' within the block, if there is one.
156 unsigned CXXThisIndex;
160 EHScopeStack::stable_iterator Cleanup;
161 CharUnits::QuantityType Offset;
163 /// Type of the capture field. Normally, this is identical to the type of
164 /// the capture's VarDecl, but can be different if there is an enclosing
169 bool isIndex() const { return (Data & 1) != 0; }
170 bool isConstant() const { return !isIndex(); }
172 unsigned getIndex() const {
176 CharUnits getOffset() const {
178 return CharUnits::fromQuantity(Offset);
180 EHScopeStack::stable_iterator getCleanup() const {
184 void setCleanup(EHScopeStack::stable_iterator cleanup) {
189 llvm::Value *getConstant() const {
190 assert(isConstant());
191 return reinterpret_cast<llvm::Value*>(Data);
194 QualType fieldType() const {
198 static Capture makeIndex(unsigned index, CharUnits offset,
199 QualType FieldType) {
201 v.Data = (index << 1) | 1;
202 v.Offset = offset.getQuantity();
203 v.FieldType = FieldType;
207 static Capture makeConstant(llvm::Value *value) {
209 v.Data = reinterpret_cast<uintptr_t>(value);
214 /// CanBeGlobal - True if the block can be global, i.e. it has
215 /// no non-constant captures.
216 bool CanBeGlobal : 1;
218 /// True if the block has captures that would necessitate custom copy or
219 /// dispose helper functions if the block were escaping.
220 bool NeedsCopyDispose : 1;
222 /// HasCXXObject - True if the block's custom copy/dispose functions
223 /// need to be run even in GC mode.
224 bool HasCXXObject : 1;
226 /// UsesStret : True if the block uses an stret return. Mutable
227 /// because it gets set later in the block-creation process.
228 mutable bool UsesStret : 1;
230 /// HasCapturedVariableLayout : True if block has captured variables
231 /// and their layout meta-data has been generated.
232 bool HasCapturedVariableLayout : 1;
234 /// The mapping of allocated indexes within the block.
235 llvm::DenseMap<const VarDecl*, Capture> Captures;
237 Address LocalAddress;
238 llvm::StructType *StructureType;
239 const BlockDecl *Block;
240 const BlockExpr *BlockExpression;
242 CharUnits BlockAlign;
243 CharUnits CXXThisOffset;
245 // Offset of the gap caused by block header having a smaller
246 // alignment than the alignment of the block descriptor. This
247 // is the gap offset before the first capturued field.
248 CharUnits BlockHeaderForcedGapOffset;
249 // Gap size caused by aligning first field after block header.
250 // This could be zero if no forced alignment is required.
251 CharUnits BlockHeaderForcedGapSize;
253 /// An instruction which dominates the full-expression that the
255 llvm::Instruction *DominatingIP;
257 /// The next block in the block-info chain. Invalid if this block
258 /// info is not part of the CGF's block-info chain, which is true
259 /// if it corresponds to a global block or a block whose expression
260 /// has been encountered.
261 CGBlockInfo *NextBlockInfo;
263 const Capture &getCapture(const VarDecl *var) const {
264 return const_cast<CGBlockInfo*>(this)->getCapture(var);
266 Capture &getCapture(const VarDecl *var) {
267 llvm::DenseMap<const VarDecl*, Capture>::iterator
268 it = Captures.find(var);
269 assert(it != Captures.end() && "no entry for variable!");
273 const BlockDecl *getBlockDecl() const { return Block; }
274 const BlockExpr *getBlockExpr() const {
275 assert(BlockExpression);
276 assert(BlockExpression->getBlockDecl() == Block);
277 return BlockExpression;
280 CGBlockInfo(const BlockDecl *blockDecl, StringRef Name);
282 // Indicates whether the block needs a custom copy or dispose function.
283 bool needsCopyDisposeHelpers() const {
284 return NeedsCopyDispose && !Block->doesNotEscape();
288 } // end namespace CodeGen
289 } // end namespace clang