1 //===- llvm/InlineAsm.h - Class to represent inline asm strings -*- 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 class represents the inline asm strings, which are Value*'s that are 11 // used as the callee operand of call instructions. InlineAsm's are uniqued 12 // like constants, and created via InlineAsm::get(...). 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_IR_INLINEASM_H 17 #define LLVM_IR_INLINEASM_H 18 19 #include "llvm/ADT/StringRef.h" 20 #include "llvm/IR/Value.h" 21 #include <cassert> 22 #include <string> 23 #include <vector> 24 25 namespace llvm { 26 27 class FunctionType; 28 class PointerType; 29 template <class ConstantClass> class ConstantUniqueMap; 30 31 class InlineAsm final : public Value { 32 public: 33 enum AsmDialect { 34 AD_ATT, 35 AD_Intel 36 }; 37 38 private: 39 friend struct InlineAsmKeyType; 40 friend class ConstantUniqueMap<InlineAsm>; 41 42 std::string AsmString, Constraints; 43 FunctionType *FTy; 44 bool HasSideEffects; 45 bool IsAlignStack; 46 AsmDialect Dialect; 47 48 InlineAsm(FunctionType *Ty, const std::string &AsmString, 49 const std::string &Constraints, bool hasSideEffects, 50 bool isAlignStack, AsmDialect asmDialect); 51 52 /// When the ConstantUniqueMap merges two types and makes two InlineAsms 53 /// identical, it destroys one of them with this method. 54 void destroyConstant(); 55 56 public: 57 InlineAsm(const InlineAsm &) = delete; 58 InlineAsm &operator=(const InlineAsm &) = delete; 59 60 /// InlineAsm::get - Return the specified uniqued inline asm string. 61 /// 62 static InlineAsm *get(FunctionType *Ty, StringRef AsmString, 63 StringRef Constraints, bool hasSideEffects, 64 bool isAlignStack = false, 65 AsmDialect asmDialect = AD_ATT); 66 67 bool hasSideEffects() const { return HasSideEffects; } 68 bool isAlignStack() const { return IsAlignStack; } 69 AsmDialect getDialect() const { return Dialect; } 70 71 /// getType - InlineAsm's are always pointers. 72 /// 73 PointerType *getType() const { 74 return reinterpret_cast<PointerType*>(Value::getType()); 75 } 76 77 /// getFunctionType - InlineAsm's are always pointers to functions. 78 /// 79 FunctionType *getFunctionType() const; 80 81 const std::string &getAsmString() const { return AsmString; } 82 const std::string &getConstraintString() const { return Constraints; } 83 84 /// Verify - This static method can be used by the parser to check to see if 85 /// the specified constraint string is legal for the type. This returns true 86 /// if legal, false if not. 87 /// 88 static bool Verify(FunctionType *Ty, StringRef Constraints); 89 90 // Constraint String Parsing 91 enum ConstraintPrefix { 92 isInput, // 'x' 93 isOutput, // '=x' 94 isClobber // '~x' 95 }; 96 97 using ConstraintCodeVector = std::vector<std::string>; 98 99 struct SubConstraintInfo { 100 /// MatchingInput - If this is not -1, this is an output constraint where an 101 /// input constraint is required to match it (e.g. "0"). The value is the 102 /// constraint number that matches this one (for example, if this is 103 /// constraint #0 and constraint #4 has the value "0", this will be 4). 104 signed char MatchingInput = -1; 105 106 /// Code - The constraint code, either the register name (in braces) or the 107 /// constraint letter/number. 108 ConstraintCodeVector Codes; 109 110 /// Default constructor. 111 SubConstraintInfo() = default; 112 }; 113 114 using SubConstraintInfoVector = std::vector<SubConstraintInfo>; 115 struct ConstraintInfo; 116 using ConstraintInfoVector = std::vector<ConstraintInfo>; 117 118 struct ConstraintInfo { 119 /// Type - The basic type of the constraint: input/output/clobber 120 /// 121 ConstraintPrefix Type = isInput; 122 123 /// isEarlyClobber - "&": output operand writes result before inputs are all 124 /// read. This is only ever set for an output operand. 125 bool isEarlyClobber = false; 126 127 /// MatchingInput - If this is not -1, this is an output constraint where an 128 /// input constraint is required to match it (e.g. "0"). The value is the 129 /// constraint number that matches this one (for example, if this is 130 /// constraint #0 and constraint #4 has the value "0", this will be 4). 131 signed char MatchingInput = -1; 132 133 /// hasMatchingInput - Return true if this is an output constraint that has 134 /// a matching input constraint. 135 bool hasMatchingInput() const { return MatchingInput != -1; } 136 137 /// isCommutative - This is set to true for a constraint that is commutative 138 /// with the next operand. 139 bool isCommutative = false; 140 141 /// isIndirect - True if this operand is an indirect operand. This means 142 /// that the address of the source or destination is present in the call 143 /// instruction, instead of it being returned or passed in explicitly. This 144 /// is represented with a '*' in the asm string. 145 bool isIndirect = false; 146 147 /// Code - The constraint code, either the register name (in braces) or the 148 /// constraint letter/number. 149 ConstraintCodeVector Codes; 150 151 /// isMultipleAlternative - '|': has multiple-alternative constraints. 152 bool isMultipleAlternative = false; 153 154 /// multipleAlternatives - If there are multiple alternative constraints, 155 /// this array will contain them. Otherwise it will be empty. 156 SubConstraintInfoVector multipleAlternatives; 157 158 /// The currently selected alternative constraint index. 159 unsigned currentAlternativeIndex = 0; 160 161 /// Default constructor. 162 ConstraintInfo() = default; 163 164 /// Parse - Analyze the specified string (e.g. "=*&{eax}") and fill in the 165 /// fields in this structure. If the constraint string is not understood, 166 /// return true, otherwise return false. 167 bool Parse(StringRef Str, ConstraintInfoVector &ConstraintsSoFar); 168 169 /// selectAlternative - Point this constraint to the alternative constraint 170 /// indicated by the index. 171 void selectAlternative(unsigned index); 172 }; 173 174 /// ParseConstraints - Split up the constraint string into the specific 175 /// constraints and their prefixes. If this returns an empty vector, and if 176 /// the constraint string itself isn't empty, there was an error parsing. 177 static ConstraintInfoVector ParseConstraints(StringRef ConstraintString); 178 179 /// ParseConstraints - Parse the constraints of this inlineasm object, 180 /// returning them the same way that ParseConstraints(str) does. 181 ConstraintInfoVector ParseConstraints() const { 182 return ParseConstraints(Constraints); 183 } 184 185 // Methods for support type inquiry through isa, cast, and dyn_cast: 186 static bool classof(const Value *V) { 187 return V->getValueID() == Value::InlineAsmVal; 188 } 189 190 // These are helper methods for dealing with flags in the INLINEASM SDNode 191 // in the backend. 192 // 193 // The encoding of the flag word is currently: 194 // Bits 2-0 - A Kind_* value indicating the kind of the operand. 195 // Bits 15-3 - The number of SDNode operands associated with this inline 196 // assembly operand. 197 // If bit 31 is set: 198 // Bit 30-16 - The operand number that this operand must match. 199 // When bits 2-0 are Kind_Mem, the Constraint_* value must be 200 // obtained from the flags for this operand number. 201 // Else if bits 2-0 are Kind_Mem: 202 // Bit 30-16 - A Constraint_* value indicating the original constraint 203 // code. 204 // Else: 205 // Bit 30-16 - The register class ID to use for the operand. 206 207 enum : uint32_t { 208 // Fixed operands on an INLINEASM SDNode. 209 Op_InputChain = 0, 210 Op_AsmString = 1, 211 Op_MDNode = 2, 212 Op_ExtraInfo = 3, // HasSideEffects, IsAlignStack, AsmDialect. 213 Op_FirstOperand = 4, 214 215 // Fixed operands on an INLINEASM MachineInstr. 216 MIOp_AsmString = 0, 217 MIOp_ExtraInfo = 1, // HasSideEffects, IsAlignStack, AsmDialect. 218 MIOp_FirstOperand = 2, 219 220 // Interpretation of the MIOp_ExtraInfo bit field. 221 Extra_HasSideEffects = 1, 222 Extra_IsAlignStack = 2, 223 Extra_AsmDialect = 4, 224 Extra_MayLoad = 8, 225 Extra_MayStore = 16, 226 Extra_IsConvergent = 32, 227 228 // Inline asm operands map to multiple SDNode / MachineInstr operands. 229 // The first operand is an immediate describing the asm operand, the low 230 // bits is the kind: 231 Kind_RegUse = 1, // Input register, "r". 232 Kind_RegDef = 2, // Output register, "=r". 233 Kind_RegDefEarlyClobber = 3, // Early-clobber output register, "=&r". 234 Kind_Clobber = 4, // Clobbered register, "~r". 235 Kind_Imm = 5, // Immediate. 236 Kind_Mem = 6, // Memory operand, "m". 237 238 // Memory constraint codes. 239 // These could be tablegenerated but there's little need to do that since 240 // there's plenty of space in the encoding to support the union of all 241 // constraint codes for all targets. 242 Constraint_Unknown = 0, 243 Constraint_es, 244 Constraint_i, 245 Constraint_m, 246 Constraint_o, 247 Constraint_v, 248 Constraint_Q, 249 Constraint_R, 250 Constraint_S, 251 Constraint_T, 252 Constraint_Um, 253 Constraint_Un, 254 Constraint_Uq, 255 Constraint_Us, 256 Constraint_Ut, 257 Constraint_Uv, 258 Constraint_Uy, 259 Constraint_X, 260 Constraint_Z, 261 Constraint_ZC, 262 Constraint_Zy, 263 Constraints_Max = Constraint_Zy, 264 Constraints_ShiftAmount = 16, 265 266 Flag_MatchingOperand = 0x80000000 267 }; 268 269 static unsigned getFlagWord(unsigned Kind, unsigned NumOps) { 270 assert(((NumOps << 3) & ~0xffff) == 0 && "Too many inline asm operands!"); 271 assert(Kind >= Kind_RegUse && Kind <= Kind_Mem && "Invalid Kind"); 272 return Kind | (NumOps << 3); 273 } 274 275 static bool isRegDefKind(unsigned Flag){ return getKind(Flag) == Kind_RegDef;} 276 static bool isImmKind(unsigned Flag) { return getKind(Flag) == Kind_Imm; } 277 static bool isMemKind(unsigned Flag) { return getKind(Flag) == Kind_Mem; } 278 static bool isRegDefEarlyClobberKind(unsigned Flag) { 279 return getKind(Flag) == Kind_RegDefEarlyClobber; 280 } 281 static bool isClobberKind(unsigned Flag) { 282 return getKind(Flag) == Kind_Clobber; 283 } 284 285 /// getFlagWordForMatchingOp - Augment an existing flag word returned by 286 /// getFlagWord with information indicating that this input operand is tied 287 /// to a previous output operand. 288 static unsigned getFlagWordForMatchingOp(unsigned InputFlag, 289 unsigned MatchedOperandNo) { 290 assert(MatchedOperandNo <= 0x7fff && "Too big matched operand"); 291 assert((InputFlag & ~0xffff) == 0 && "High bits already contain data"); 292 return InputFlag | Flag_MatchingOperand | (MatchedOperandNo << 16); 293 } 294 295 /// getFlagWordForRegClass - Augment an existing flag word returned by 296 /// getFlagWord with the required register class for the following register 297 /// operands. 298 /// A tied use operand cannot have a register class, use the register class 299 /// from the def operand instead. 300 static unsigned getFlagWordForRegClass(unsigned InputFlag, unsigned RC) { 301 // Store RC + 1, reserve the value 0 to mean 'no register class'. 302 ++RC; 303 assert(!isImmKind(InputFlag) && "Immediates cannot have a register class"); 304 assert(!isMemKind(InputFlag) && "Memory operand cannot have a register class"); 305 assert(RC <= 0x7fff && "Too large register class ID"); 306 assert((InputFlag & ~0xffff) == 0 && "High bits already contain data"); 307 return InputFlag | (RC << 16); 308 } 309 310 /// Augment an existing flag word returned by getFlagWord with the constraint 311 /// code for a memory constraint. 312 static unsigned getFlagWordForMem(unsigned InputFlag, unsigned Constraint) { 313 assert(isMemKind(InputFlag) && "InputFlag is not a memory constraint!"); 314 assert(Constraint <= 0x7fff && "Too large a memory constraint ID"); 315 assert(Constraint <= Constraints_Max && "Unknown constraint ID"); 316 assert((InputFlag & ~0xffff) == 0 && "High bits already contain data"); 317 return InputFlag | (Constraint << Constraints_ShiftAmount); 318 } 319 320 static unsigned convertMemFlagWordToMatchingFlagWord(unsigned InputFlag) { 321 assert(isMemKind(InputFlag)); 322 return InputFlag & ~(0x7fff << Constraints_ShiftAmount); 323 } 324 325 static unsigned getKind(unsigned Flags) { 326 return Flags & 7; 327 } 328 329 static unsigned getMemoryConstraintID(unsigned Flag) { 330 assert(isMemKind(Flag)); 331 return (Flag >> Constraints_ShiftAmount) & 0x7fff; 332 } 333 334 /// getNumOperandRegisters - Extract the number of registers field from the 335 /// inline asm operand flag. 336 static unsigned getNumOperandRegisters(unsigned Flag) { 337 return (Flag & 0xffff) >> 3; 338 } 339 340 /// isUseOperandTiedToDef - Return true if the flag of the inline asm 341 /// operand indicates it is an use operand that's matched to a def operand. 342 static bool isUseOperandTiedToDef(unsigned Flag, unsigned &Idx) { 343 if ((Flag & Flag_MatchingOperand) == 0) 344 return false; 345 Idx = (Flag & ~Flag_MatchingOperand) >> 16; 346 return true; 347 } 348 349 /// hasRegClassConstraint - Returns true if the flag contains a register 350 /// class constraint. Sets RC to the register class ID. 351 static bool hasRegClassConstraint(unsigned Flag, unsigned &RC) { 352 if (Flag & Flag_MatchingOperand) 353 return false; 354 unsigned High = Flag >> 16; 355 // getFlagWordForRegClass() uses 0 to mean no register class, and otherwise 356 // stores RC + 1. 357 if (!High) 358 return false; 359 RC = High - 1; 360 return true; 361 } 362 }; 363 364 } // end namespace llvm 365 366 #endif // LLVM_IR_INLINEASM_H 367
