MCExpr.h revision 7597212abced110723f2fee985a7d60557c092ec 
1//===- MCExpr.h - Assembly Level Expressions --------------------*- 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#ifndef LLVM_MC_MCEXPR_H
11#define LLVM_MC_MCEXPR_H
12
13#include "llvm/ADT/DenseMap.h"
14#include "llvm/Support/Casting.h"
15#include "llvm/Support/DataTypes.h"
16
17namespace llvm {
18class MCAsmInfo;
19class MCAsmLayout;
20class MCAssembler;
21class MCContext;
22class MCSectionData;
23class MCSymbol;
24class MCValue;
25class raw_ostream;
26class StringRef;
27typedef DenseMap<const MCSectionData*, uint64_t> SectionAddrMap;
28
29/// MCExpr - Base class for the full range of assembler expressions which are
30/// needed for parsing.
31class MCExpr {
32public:
33  enum ExprKind {
34    Binary,    ///< Binary expressions.
35    Constant,  ///< Constant expressions.
36    SymbolRef, ///< References to labels and assigned expressions.
37    Unary,     ///< Unary expressions.
38    Target     ///< Target specific expression.
39  };
40
41private:
42  ExprKind Kind;
43
44  MCExpr(const MCExpr&); // DO NOT IMPLEMENT
45  void operator=(const MCExpr&); // DO NOT IMPLEMENT
46
47  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
48                          const MCAsmLayout *Layout,
49                          const SectionAddrMap *Addrs) const;
50protected:
51  explicit MCExpr(ExprKind _Kind) : Kind(_Kind) {}
52
53  bool EvaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
54                                 const MCAsmLayout *Layout,
55                                 const SectionAddrMap *Addrs,
56                                 bool InSet) const;
57public:
58  /// @name Accessors
59  /// @{
60
61  ExprKind getKind() const { return Kind; }
62
63  /// @}
64  /// @name Utility Methods
65  /// @{
66
67  void print(raw_ostream &OS) const;
68  void dump() const;
69
70  /// @}
71  /// @name Expression Evaluation
72  /// @{
73
74  /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
75  ///
76  /// @param Res - The absolute value, if evaluation succeeds.
77  /// @param Layout - The assembler layout object to use for evaluating symbol
78  /// values. If not given, then only non-symbolic expressions will be
79  /// evaluated.
80  /// @result - True on success.
81  bool EvaluateAsAbsolute(int64_t &Res) const;
82  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const;
83  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
84  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout,
85                          const SectionAddrMap &Addrs) const;
86
87  /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
88  /// value, i.e. an expression of the fixed form (a - b + constant).
89  ///
90  /// @param Res - The relocatable value, if evaluation succeeds.
91  /// @param Layout - The assembler layout object to use for evaluating values.
92  /// @result - True on success.
93  bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout &Layout) const;
94
95  /// @}
96
97  static bool classof(const MCExpr *) { return true; }
98};
99
100inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
101  E.print(OS);
102  return OS;
103}
104
105//// MCConstantExpr - Represent a constant integer expression.
106class MCConstantExpr : public MCExpr {
107  int64_t Value;
108
109  explicit MCConstantExpr(int64_t _Value)
110    : MCExpr(MCExpr::Constant), Value(_Value) {}
111
112public:
113  /// @name Construction
114  /// @{
115
116  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
117
118  /// @}
119  /// @name Accessors
120  /// @{
121
122  int64_t getValue() const { return Value; }
123
124  /// @}
125
126  static bool classof(const MCExpr *E) {
127    return E->getKind() == MCExpr::Constant;
128  }
129  static bool classof(const MCConstantExpr *) { return true; }
130};
131
132/// MCSymbolRefExpr - Represent a reference to a symbol from inside an
133/// expression.
134///
135/// A symbol reference in an expression may be a use of a label, a use of an
136/// assembler variable (defined constant), or constitute an implicit definition
137/// of the symbol as external.
138class MCSymbolRefExpr : public MCExpr {
139public:
140  enum VariantKind {
141    VK_None,
142    VK_Invalid,
143
144    VK_GOT,
145    VK_GOTOFF,
146    VK_GOTPCREL,
147    VK_GOTTPOFF,
148    VK_INDNTPOFF,
149    VK_NTPOFF,
150    VK_GOTNTPOFF,
151    VK_PLT,
152    VK_TLSGD,
153    VK_TLSLD,
154    VK_TLSLDM,
155    VK_TPOFF,
156    VK_DTPOFF,
157    VK_TLVP,      // Mach-O thread local variable relocation
158    // FIXME: We'd really like to use the generic Kinds listed above for these.
159    VK_ARM_PLT,   // ARM-style PLT references. i.e., (PLT) instead of @PLT
160    VK_ARM_TLSGD, //   ditto for TLSGD, GOT, GOTOFF, TPOFF and GOTTPOFF
161    VK_ARM_GOT,
162    VK_ARM_GOTOFF,
163    VK_ARM_TPOFF,
164    VK_ARM_GOTTPOFF,
165
166    VK_PPC_TOC,
167    VK_PPC_HA16,  // ha16(symbol)
168    VK_PPC_LO16   // lo16(symbol)
169  };
170
171private:
172  /// The symbol being referenced.
173  const MCSymbol *Symbol;
174
175  /// The symbol reference modifier.
176  const VariantKind Kind;
177
178  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
179    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
180
181public:
182  /// @name Construction
183  /// @{
184
185  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
186    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
187  }
188
189  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
190                                       MCContext &Ctx);
191  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
192                                       MCContext &Ctx);
193
194  /// @}
195  /// @name Accessors
196  /// @{
197
198  const MCSymbol &getSymbol() const { return *Symbol; }
199
200  VariantKind getKind() const { return Kind; }
201
202  /// @}
203  /// @name Static Utility Functions
204  /// @{
205
206  static StringRef getVariantKindName(VariantKind Kind);
207
208  static VariantKind getVariantKindForName(StringRef Name);
209
210  /// @}
211
212  static bool classof(const MCExpr *E) {
213    return E->getKind() == MCExpr::SymbolRef;
214  }
215  static bool classof(const MCSymbolRefExpr *) { return true; }
216};
217
218/// MCUnaryExpr - Unary assembler expressions.
219class MCUnaryExpr : public MCExpr {
220public:
221  enum Opcode {
222    LNot,  ///< Logical negation.
223    Minus, ///< Unary minus.
224    Not,   ///< Bitwise negation.
225    Plus   ///< Unary plus.
226  };
227
228private:
229  Opcode Op;
230  const MCExpr *Expr;
231
232  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
233    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
234
235public:
236  /// @name Construction
237  /// @{
238
239  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
240                                   MCContext &Ctx);
241  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
242    return Create(LNot, Expr, Ctx);
243  }
244  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
245    return Create(Minus, Expr, Ctx);
246  }
247  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
248    return Create(Not, Expr, Ctx);
249  }
250  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
251    return Create(Plus, Expr, Ctx);
252  }
253
254  /// @}
255  /// @name Accessors
256  /// @{
257
258  /// getOpcode - Get the kind of this unary expression.
259  Opcode getOpcode() const { return Op; }
260
261  /// getSubExpr - Get the child of this unary expression.
262  const MCExpr *getSubExpr() const { return Expr; }
263
264  /// @}
265
266  static bool classof(const MCExpr *E) {
267    return E->getKind() == MCExpr::Unary;
268  }
269  static bool classof(const MCUnaryExpr *) { return true; }
270};
271
272/// MCBinaryExpr - Binary assembler expressions.
273class MCBinaryExpr : public MCExpr {
274public:
275  enum Opcode {
276    Add,  ///< Addition.
277    And,  ///< Bitwise and.
278    Div,  ///< Signed division.
279    EQ,   ///< Equality comparison.
280    GT,   ///< Signed greater than comparison (result is either 0 or some
281          ///< target-specific non-zero value)
282    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
283          ///< some target-specific non-zero value).
284    LAnd, ///< Logical and.
285    LOr,  ///< Logical or.
286    LT,   ///< Signed less than comparison (result is either 0 or
287          ///< some target-specific non-zero value).
288    LTE,  ///< Signed less than or equal comparison (result is either 0 or
289          ///< some target-specific non-zero value).
290    Mod,  ///< Signed remainder.
291    Mul,  ///< Multiplication.
292    NE,   ///< Inequality comparison.
293    Or,   ///< Bitwise or.
294    Shl,  ///< Shift left.
295    Shr,  ///< Shift right (arithmetic or logical, depending on target)
296    Sub,  ///< Subtraction.
297    Xor   ///< Bitwise exclusive or.
298  };
299
300private:
301  Opcode Op;
302  const MCExpr *LHS, *RHS;
303
304  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
305    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
306
307public:
308  /// @name Construction
309  /// @{
310
311  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
312                                    const MCExpr *RHS, MCContext &Ctx);
313  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
314                                       MCContext &Ctx) {
315    return Create(Add, LHS, RHS, Ctx);
316  }
317  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
318                                       MCContext &Ctx) {
319    return Create(And, LHS, RHS, Ctx);
320  }
321  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
322                                       MCContext &Ctx) {
323    return Create(Div, LHS, RHS, Ctx);
324  }
325  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
326                                      MCContext &Ctx) {
327    return Create(EQ, LHS, RHS, Ctx);
328  }
329  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
330                                      MCContext &Ctx) {
331    return Create(GT, LHS, RHS, Ctx);
332  }
333  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
334                                       MCContext &Ctx) {
335    return Create(GTE, LHS, RHS, Ctx);
336  }
337  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
338                                        MCContext &Ctx) {
339    return Create(LAnd, LHS, RHS, Ctx);
340  }
341  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
342                                       MCContext &Ctx) {
343    return Create(LOr, LHS, RHS, Ctx);
344  }
345  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
346                                      MCContext &Ctx) {
347    return Create(LT, LHS, RHS, Ctx);
348  }
349  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
350                                       MCContext &Ctx) {
351    return Create(LTE, LHS, RHS, Ctx);
352  }
353  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
354                                       MCContext &Ctx) {
355    return Create(Mod, LHS, RHS, Ctx);
356  }
357  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
358                                       MCContext &Ctx) {
359    return Create(Mul, LHS, RHS, Ctx);
360  }
361  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
362                                      MCContext &Ctx) {
363    return Create(NE, LHS, RHS, Ctx);
364  }
365  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
366                                      MCContext &Ctx) {
367    return Create(Or, LHS, RHS, Ctx);
368  }
369  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
370                                       MCContext &Ctx) {
371    return Create(Shl, LHS, RHS, Ctx);
372  }
373  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
374                                       MCContext &Ctx) {
375    return Create(Shr, LHS, RHS, Ctx);
376  }
377  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
378                                       MCContext &Ctx) {
379    return Create(Sub, LHS, RHS, Ctx);
380  }
381  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
382                                       MCContext &Ctx) {
383    return Create(Xor, LHS, RHS, Ctx);
384  }
385
386  /// @}
387  /// @name Accessors
388  /// @{
389
390  /// getOpcode - Get the kind of this binary expression.
391  Opcode getOpcode() const { return Op; }
392
393  /// getLHS - Get the left-hand side expression of the binary operator.
394  const MCExpr *getLHS() const { return LHS; }
395
396  /// getRHS - Get the right-hand side expression of the binary operator.
397  const MCExpr *getRHS() const { return RHS; }
398
399  /// @}
400
401  static bool classof(const MCExpr *E) {
402    return E->getKind() == MCExpr::Binary;
403  }
404  static bool classof(const MCBinaryExpr *) { return true; }
405};
406
407/// MCTargetExpr - This is an extension point for target-specific MCExpr
408/// subclasses to implement.
409///
410/// NOTE: All subclasses are required to have trivial destructors because
411/// MCExprs are bump pointer allocated and not destructed.
412class MCTargetExpr : public MCExpr {
413  virtual void Anchor();
414protected:
415  MCTargetExpr() : MCExpr(Target) {}
416  virtual ~MCTargetExpr() {}
417public:
418
419  virtual void PrintImpl(raw_ostream &OS) const = 0;
420  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
421                                         const MCAsmLayout *Layout) const = 0;
422  virtual void AddValueSymbols(MCAssembler *) const = 0;
423
424  static bool classof(const MCExpr *E) {
425    return E->getKind() == MCExpr::Target;
426  }
427  static bool classof(const MCTargetExpr *) { return true; }
428};
429
430} // end namespace llvm
431
432#endif
433