aboutsummaryrefslogtreecommitdiffstats
path: root/include/llvm/IR/InlineAsm.h
blob: 6ae4122d936e71a3e9f7da86b3463247a9e6d7fa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
//===-- llvm/InlineAsm.h - Class to represent inline asm strings-*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This class represents the inline asm strings, which are Value*'s that are
// used as the callee operand of call instructions.  InlineAsm's are uniqued
// like constants, and created via InlineAsm::get(...).
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_INLINEASM_H
#define LLVM_IR_INLINEASM_H

#include "llvm/ADT/StringRef.h"
#include "llvm/IR/Value.h"
#include <vector>

namespace llvm {

class PointerType;
class FunctionType;
class Module;

struct InlineAsmKeyType;
template <class ConstantClass> class ConstantUniqueMap;

class InlineAsm : public Value {
public:
  enum AsmDialect {
    AD_ATT,
    AD_Intel
  };

private:
  friend struct InlineAsmKeyType;
  friend class ConstantUniqueMap<InlineAsm>;

  InlineAsm(const InlineAsm &) = delete;
  void operator=(const InlineAsm&) = delete;

  std::string AsmString, Constraints;
  bool HasSideEffects;
  bool IsAlignStack;
  AsmDialect Dialect;

  InlineAsm(PointerType *Ty, const std::string &AsmString,
            const std::string &Constraints, bool hasSideEffects,
            bool isAlignStack, AsmDialect asmDialect);
  virtual ~InlineAsm();

  /// When the ConstantUniqueMap merges two types and makes two InlineAsms
  /// identical, it destroys one of them with this method.
  void destroyConstant();
public:

  /// InlineAsm::get - Return the specified uniqued inline asm string.
  ///
  static InlineAsm *get(FunctionType *Ty, StringRef AsmString,
                        StringRef Constraints, bool hasSideEffects,
                        bool isAlignStack = false,
                        AsmDialect asmDialect = AD_ATT);
  
  bool hasSideEffects() const { return HasSideEffects; }
  bool isAlignStack() const { return IsAlignStack; }
  AsmDialect getDialect() const { return Dialect; }

  /// getType - InlineAsm's are always pointers.
  ///
  PointerType *getType() const {
    return reinterpret_cast<PointerType*>(Value::getType());
  }
  
  /// getFunctionType - InlineAsm's are always pointers to functions.
  ///
  FunctionType *getFunctionType() const;
  
  const std::string &getAsmString() const { return AsmString; }
  const std::string &getConstraintString() const { return Constraints; }

  /// Verify - This static method can be used by the parser to check to see if
  /// the specified constraint string is legal for the type.  This returns true
  /// if legal, false if not.
  ///
  static bool Verify(FunctionType *Ty, StringRef Constraints);

  // Constraint String Parsing 
  enum ConstraintPrefix {
    isInput,            // 'x'
    isOutput,           // '=x'
    isClobber           // '~x'
  };
  
  typedef std::vector<std::string> ConstraintCodeVector;
  
  struct SubConstraintInfo {
    /// MatchingInput - If this is not -1, this is an output constraint where an
    /// input constraint is required to match it (e.g. "0").  The value is the
    /// constraint number that matches this one (for example, if this is
    /// constraint #0 and constraint #4 has the value "0", this will be 4).
    signed char MatchingInput;
    /// Code - The constraint code, either the register name (in braces) or the
    /// constraint letter/number.
    ConstraintCodeVector Codes;
    /// Default constructor.
    SubConstraintInfo() : MatchingInput(-1) {}
  };

  typedef std::vector<SubConstraintInfo> SubConstraintInfoVector;
  struct ConstraintInfo;
  typedef std::vector<ConstraintInfo> ConstraintInfoVector;
  
  struct ConstraintInfo {
    /// Type - The basic type of the constraint: input/output/clobber
    ///
    ConstraintPrefix Type;
    
    /// isEarlyClobber - "&": output operand writes result before inputs are all
    /// read.  This is only ever set for an output operand.
    bool isEarlyClobber; 
    
    /// MatchingInput - If this is not -1, this is an output constraint where an
    /// input constraint is required to match it (e.g. "0").  The value is the
    /// constraint number that matches this one (for example, if this is
    /// constraint #0 and constraint #4 has the value "0", this will be 4).
    signed char MatchingInput;
    
    /// hasMatchingInput - Return true if this is an output constraint that has
    /// a matching input constraint.
    bool hasMatchingInput() const { return MatchingInput != -1; }
    
    /// isCommutative - This is set to true for a constraint that is commutative
    /// with the next operand.
    bool isCommutative;
    
    /// isIndirect - True if this operand is an indirect operand.  This means
    /// that the address of the source or destination is present in the call
    /// instruction, instead of it being returned or passed in explicitly.  This
    /// is represented with a '*' in the asm string.
    bool isIndirect;
    
    /// Code - The constraint code, either the register name (in braces) or the
    /// constraint letter/number.
    ConstraintCodeVector Codes;
    
    /// isMultipleAlternative - '|': has multiple-alternative constraints.
    bool isMultipleAlternative;
    
    /// multipleAlternatives - If there are multiple alternative constraints,
    /// this array will contain them.  Otherwise it will be empty.
    SubConstraintInfoVector multipleAlternatives;
    
    /// The currently selected alternative constraint index.
    unsigned currentAlternativeIndex;
    
    ///Default constructor.
    ConstraintInfo();
    
    /// Parse - Analyze the specified string (e.g. "=*&{eax}") and fill in the
    /// fields in this structure.  If the constraint string is not understood,
    /// return true, otherwise return false.
    bool Parse(StringRef Str, ConstraintInfoVector &ConstraintsSoFar);
               
    /// selectAlternative - Point this constraint to the alternative constraint
    /// indicated by the index.
    void selectAlternative(unsigned index);
  };
  
  /// ParseConstraints - Split up the constraint string into the specific
  /// constraints and their prefixes.  If this returns an empty vector, and if
  /// the constraint string itself isn't empty, there was an error parsing.
  static ConstraintInfoVector ParseConstraints(StringRef ConstraintString);
  
  /// ParseConstraints - Parse the constraints of this inlineasm object, 
  /// returning them the same way that ParseConstraints(str) does.
  ConstraintInfoVector ParseConstraints() const {
    return ParseConstraints(Constraints);
  }
  
  // Methods for support type inquiry through isa, cast, and dyn_cast:
  static inline bool classof(const Value *V) {
    return V->getValueID() == Value::InlineAsmVal;
  }

  
  // These are helper methods for dealing with flags in the INLINEASM SDNode
  // in the backend.
  //
  // The encoding of the flag word is currently:
  //   Bits 2-0 - A Kind_* value indicating the kind of the operand.
  //   Bits 15-3 - The number of SDNode operands associated with this inline
  //               assembly operand.
  //   If bit 31 is set:
  //     Bit 30-16 - The operand number that this operand must match.
  //                 When bits 2-0 are Kind_Mem, the Constraint_* value must be
  //                 obtained from the flags for this operand number.
  //   Else if bits 2-0 are Kind_Mem:
  //     Bit 30-16 - A Constraint_* value indicating the original constraint
  //                 code.
  //   Else:
  //     Bit 30-16 - The register class ID to use for the operand.
  
  enum : uint32_t {
    // Fixed operands on an INLINEASM SDNode.
    Op_InputChain = 0,
    Op_AsmString = 1,
    Op_MDNode = 2,
    Op_ExtraInfo = 3,    // HasSideEffects, IsAlignStack, AsmDialect.
    Op_FirstOperand = 4,

    // Fixed operands on an INLINEASM MachineInstr.
    MIOp_AsmString = 0,
    MIOp_ExtraInfo = 1,    // HasSideEffects, IsAlignStack, AsmDialect.
    MIOp_FirstOperand = 2,

    // Interpretation of the MIOp_ExtraInfo bit field.
    Extra_HasSideEffects = 1,
    Extra_IsAlignStack = 2,
    Extra_AsmDialect = 4,
    Extra_MayLoad = 8,
    Extra_MayStore = 16,

    // Inline asm operands map to multiple SDNode / MachineInstr operands.
    // The first operand is an immediate describing the asm operand, the low
    // bits is the kind:
    Kind_RegUse = 1,             // Input register, "r".
    Kind_RegDef = 2,             // Output register, "=r".
    Kind_RegDefEarlyClobber = 3, // Early-clobber output register, "=&r".
    Kind_Clobber = 4,            // Clobbered register, "~r".
    Kind_Imm = 5,                // Immediate.
    Kind_Mem = 6,                // Memory operand, "m".

    // Memory constraint codes.
    // These could be tablegenerated but there's little need to do that since
    // there's plenty of space in the encoding to support the union of all
    // constraint codes for all targets.
    Constraint_Unknown = 0,
    Constraint_es,
    Constraint_i,
    Constraint_m,
    Constraint_o,
    Constraint_v,
    Constraint_Q,
    Constraint_R,
    Constraint_S,
    Constraint_T,
    Constraint_Z,
    Constraint_ZC,
    Constraint_Zy,
    Constraints_Max = Constraint_Zy,
    Constraints_ShiftAmount = 16,

    Flag_MatchingOperand = 0x80000000
  };
  
  static unsigned getFlagWord(unsigned Kind, unsigned NumOps) {
    assert(((NumOps << 3) & ~0xffff) == 0 && "Too many inline asm operands!");
    assert(Kind >= Kind_RegUse && Kind <= Kind_Mem && "Invalid Kind");
    return Kind | (NumOps << 3);
  }
  
  /// getFlagWordForMatchingOp - Augment an existing flag word returned by
  /// getFlagWord with information indicating that this input operand is tied 
  /// to a previous output operand.
  static unsigned getFlagWordForMatchingOp(unsigned InputFlag,
                                           unsigned MatchedOperandNo) {
    assert(MatchedOperandNo <= 0x7fff && "Too big matched operand");
    assert((InputFlag & ~0xffff) == 0 && "High bits already contain data");
    return InputFlag | Flag_MatchingOperand | (MatchedOperandNo << 16);
  }

  /// getFlagWordForRegClass - Augment an existing flag word returned by
  /// getFlagWord with the required register class for the following register
  /// operands.
  /// A tied use operand cannot have a register class, use the register class
  /// from the def operand instead.
  static unsigned getFlagWordForRegClass(unsigned InputFlag, unsigned RC) {
    // Store RC + 1, reserve the value 0 to mean 'no register class'.
    ++RC;
    assert(RC <= 0x7fff && "Too large register class ID");
    assert((InputFlag & ~0xffff) == 0 && "High bits already contain data");
    return InputFlag | (RC << 16);
  }

  /// Augment an existing flag word returned by getFlagWord with the constraint
  /// code for a memory constraint.
  static unsigned getFlagWordForMem(unsigned InputFlag, unsigned Constraint) {
    assert(Constraint <= 0x7fff && "Too large a memory constraint ID");
    assert(Constraint <= Constraints_Max && "Unknown constraint ID");
    assert((InputFlag & ~0xffff) == 0 && "High bits already contain data");
    return InputFlag | (Constraint << Constraints_ShiftAmount);
  }

  static unsigned convertMemFlagWordToMatchingFlagWord(unsigned InputFlag) {
    assert(isMemKind(InputFlag));
    return InputFlag & ~(0x7fff << Constraints_ShiftAmount);
  }

  static unsigned getKind(unsigned Flags) {
    return Flags & 7;
  }

  static bool isRegDefKind(unsigned Flag){ return getKind(Flag) == Kind_RegDef;}
  static bool isImmKind(unsigned Flag) { return getKind(Flag) == Kind_Imm; }
  static bool isMemKind(unsigned Flag) { return getKind(Flag) == Kind_Mem; }
  static bool isRegDefEarlyClobberKind(unsigned Flag) {
    return getKind(Flag) == Kind_RegDefEarlyClobber;
  }
  static bool isClobberKind(unsigned Flag) {
    return getKind(Flag) == Kind_Clobber;
  }

  static unsigned getMemoryConstraintID(unsigned Flag) {
    assert(isMemKind(Flag));
    return (Flag >> Constraints_ShiftAmount) & 0x7fff;
  }

  /// getNumOperandRegisters - Extract the number of registers field from the
  /// inline asm operand flag.
  static unsigned getNumOperandRegisters(unsigned Flag) {
    return (Flag & 0xffff) >> 3;
  }

  /// isUseOperandTiedToDef - Return true if the flag of the inline asm
  /// operand indicates it is an use operand that's matched to a def operand.
  static bool isUseOperandTiedToDef(unsigned Flag, unsigned &Idx) {
    if ((Flag & Flag_MatchingOperand) == 0)
      return false;
    Idx = (Flag & ~Flag_MatchingOperand) >> 16;
    return true;
  }

  /// hasRegClassConstraint - Returns true if the flag contains a register
  /// class constraint.  Sets RC to the register class ID.
  static bool hasRegClassConstraint(unsigned Flag, unsigned &RC) {
    if (Flag & Flag_MatchingOperand)
      return false;
    unsigned High = Flag >> 16;
    // getFlagWordForRegClass() uses 0 to mean no register class, and otherwise
    // stores RC + 1.
    if (!High)
      return false;
    RC = High - 1;
    return true;
  }

};

} // End llvm namespace

#endif