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 30 namespace llvm { 31 class Module; 32 class Constant; 33 class Function; 34 class GlobalValue; 35 class DataLayout; 36 class FunctionType; 37 class PointerType; 38 class Value; 39 class LLVMContext; 40 } 41 42 namespace clang { 43 44 namespace CodeGen { 45 46 class CodeGenModule; 47 class CGBlockInfo; 48 49 // Flags stored in __block variables. 50 enum 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 60 enum 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 }; 68 class BlockFlags { 69 uint32_t flags; 70 71 public: BlockFlags(uint32_t flags)72 BlockFlags(uint32_t flags) : flags(flags) {} BlockFlags()73 BlockFlags() : flags(0) {} BlockFlags(BlockLiteralFlags flag)74 BlockFlags(BlockLiteralFlags flag) : flags(flag) {} BlockFlags(BlockByrefFlags flag)75 BlockFlags(BlockByrefFlags flag) : flags(flag) {} 76 getBitMask()77 uint32_t getBitMask() const { return flags; } empty()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 }; 94 inline BlockFlags operator|(BlockLiteralFlags l, BlockLiteralFlags r) { 95 return BlockFlags(l) | BlockFlags(r); 96 } 97 98 enum 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 }; 112 113 class BlockFieldFlags { 114 uint32_t flags; 115 BlockFieldFlags(uint32_t flags)116 BlockFieldFlags(uint32_t flags) : flags(flags) {} 117 public: BlockFieldFlags()118 BlockFieldFlags() : flags(0) {} BlockFieldFlags(BlockFieldFlag_t flag)119 BlockFieldFlags(BlockFieldFlag_t flag) : flags(flag) {} 120 getBitMask()121 uint32_t getBitMask() const { return flags; } empty()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. isSpecialPointer()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 }; 139 inline 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. 144 class BlockByrefInfo { 145 public: 146 llvm::StructType *Type; 147 unsigned FieldIndex; 148 CharUnits ByrefAlignment; 149 CharUnits FieldOffset; 150 }; 151 152 /// CGBlockInfo - Information to generate a block literal. 153 class CGBlockInfo { 154 public: 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: isIndex()167 bool isIndex() const { return (Data & 1) != 0; } isConstant()168 bool isConstant() const { return !isIndex(); } 169 getIndex()170 unsigned getIndex() const { 171 assert(isIndex()); 172 return Data >> 1; 173 } getOffset()174 CharUnits getOffset() const { 175 assert(isIndex()); 176 return CharUnits::fromQuantity(Offset); 177 } getCleanup()178 EHScopeStack::stable_iterator getCleanup() const { 179 assert(isIndex()); 180 return Cleanup; 181 } setCleanup(EHScopeStack::stable_iterator cleanup)182 void setCleanup(EHScopeStack::stable_iterator cleanup) { 183 assert(isIndex()); 184 Cleanup = cleanup; 185 } 186 getConstant()187 llvm::Value *getConstant() const { 188 assert(isConstant()); 189 return reinterpret_cast<llvm::Value*>(Data); 190 } 191 makeIndex(unsigned index,CharUnits offset)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 makeConstant(llvm::Value * value)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 getCapture(const VarDecl * var)254 const Capture &getCapture(const VarDecl *var) const { 255 return const_cast<CGBlockInfo*>(this)->getCapture(var); 256 } getCapture(const VarDecl * var)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 getBlockDecl()264 const BlockDecl *getBlockDecl() const { return Block; } getBlockExpr()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