MCExpr.h revision 637d89fe0eca4fa2b9c95f6c15eb69a99bae83bc 
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/Support/Casting.h"
14#include "llvm/System/DataTypes.h"
15
16namespace llvm {
17class MCAsmInfo;
18class MCAsmLayout;
19class MCContext;
20class MCSymbol;
21class MCValue;
22class raw_ostream;
23class StringRef;
24
25/// MCExpr - Base class for the full range of assembler expressions which are
26/// needed for parsing.
27class MCExpr {
28public:
29  enum ExprKind {
30    Binary,    ///< Binary expressions.
31    Constant,  ///< Constant expressions.
32    SymbolRef, ///< References to labels and assigned expressions.
33    Unary,     ///< Unary expressions.
34    Target     ///< Target specific expression.
35  };
36
37private:
38  ExprKind Kind;
39
40  MCExpr(const MCExpr&); // DO NOT IMPLEMENT
41  void operator=(const MCExpr&); // DO NOT IMPLEMENT
42
43protected:
44  explicit MCExpr(ExprKind _Kind) : Kind(_Kind) {}
45
46public:
47  /// @name Accessors
48  /// @{
49
50  ExprKind getKind() const { return Kind; }
51
52  /// @}
53  /// @name Utility Methods
54  /// @{
55
56  void print(raw_ostream &OS) const;
57  void dump() const;
58
59  /// @}
60  /// @name Expression Evaluation
61  /// @{
62
63  /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
64  ///
65  /// @param Res - The absolute value, if evaluation succeeds.
66  /// @param Layout - The assembler layout object to use for evaluating symbol
67  /// values. If not given, then only non-symbolic expressions will be
68  /// evaluated.
69  /// @result - True on success.
70  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout = 0) const;
71
72  /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
73  /// value, i.e. an expression of the fixed form (a - b + constant).
74  ///
75  /// @param Res - The relocatable value, if evaluation succeeds.
76  /// @param Layout - The assembler layout object to use for evaluating values.
77  /// @result - True on success.
78  bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout *Layout = 0) const;
79
80  /// @}
81
82  static bool classof(const MCExpr *) { return true; }
83};
84
85inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
86  E.print(OS);
87  return OS;
88}
89
90//// MCConstantExpr - Represent a constant integer expression.
91class MCConstantExpr : public MCExpr {
92  int64_t Value;
93
94  explicit MCConstantExpr(int64_t _Value)
95    : MCExpr(MCExpr::Constant), Value(_Value) {}
96
97public:
98  /// @name Construction
99  /// @{
100
101  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
102
103  /// @}
104  /// @name Accessors
105  /// @{
106
107  int64_t getValue() const { return Value; }
108
109  /// @}
110
111  static bool classof(const MCExpr *E) {
112    return E->getKind() == MCExpr::Constant;
113  }
114  static bool classof(const MCConstantExpr *) { return true; }
115};
116
117/// MCSymbolRefExpr - Represent a reference to a symbol from inside an
118/// expression.
119///
120/// A symbol reference in an expression may be a use of a label, a use of an
121/// assembler variable (defined constant), or constitute an implicit definition
122/// of the symbol as external.
123class MCSymbolRefExpr : public MCExpr {
124public:
125  enum VariantKind {
126    VK_None,
127    VK_Invalid,
128
129    VK_GOT,
130    VK_GOTOFF,
131    VK_GOTPCREL,
132    VK_GOTTPOFF,
133    VK_INDNTPOFF,
134    VK_NTPOFF,
135    VK_PLT,
136    VK_TLSGD,
137    VK_TPOFF,
138    VK_ARM_HI16, // The R_ARM_MOVT_ABS relocation (:upper16: in the asm file)
139    VK_ARM_LO16, // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the asm file)
140    VK_ARM_PLT,  // ARM-style PLT symbol references. i.e., (PLT) instead of @PLT
141    VK_TLVP // Mach-O thread local variable relocation
142  };
143
144private:
145  /// The symbol being referenced.
146  const MCSymbol *Symbol;
147
148  /// The symbol reference modifier.
149  const VariantKind Kind;
150
151  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
152    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
153
154public:
155  /// @name Construction
156  /// @{
157
158  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
159    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
160  }
161
162  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
163                                       MCContext &Ctx);
164  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
165                                       MCContext &Ctx);
166
167  /// @}
168  /// @name Accessors
169  /// @{
170
171  const MCSymbol &getSymbol() const { return *Symbol; }
172
173  VariantKind getKind() const { return Kind; }
174
175  /// @}
176  /// @name Static Utility Functions
177  /// @{
178
179  static StringRef getVariantKindName(VariantKind Kind);
180
181  static VariantKind getVariantKindForName(StringRef Name);
182
183  /// @}
184
185  static bool classof(const MCExpr *E) {
186    return E->getKind() == MCExpr::SymbolRef;
187  }
188  static bool classof(const MCSymbolRefExpr *) { return true; }
189};
190
191/// MCUnaryExpr - Unary assembler expressions.
192class MCUnaryExpr : public MCExpr {
193public:
194  enum Opcode {
195    LNot,  ///< Logical negation.
196    Minus, ///< Unary minus.
197    Not,   ///< Bitwise negation.
198    Plus   ///< Unary plus.
199  };
200
201private:
202  Opcode Op;
203  const MCExpr *Expr;
204
205  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
206    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
207
208public:
209  /// @name Construction
210  /// @{
211
212  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
213                                   MCContext &Ctx);
214  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
215    return Create(LNot, Expr, Ctx);
216  }
217  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
218    return Create(Minus, Expr, Ctx);
219  }
220  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
221    return Create(Not, Expr, Ctx);
222  }
223  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
224    return Create(Plus, Expr, Ctx);
225  }
226
227  /// @}
228  /// @name Accessors
229  /// @{
230
231  /// getOpcode - Get the kind of this unary expression.
232  Opcode getOpcode() const { return Op; }
233
234  /// getSubExpr - Get the child of this unary expression.
235  const MCExpr *getSubExpr() const { return Expr; }
236
237  /// @}
238
239  static bool classof(const MCExpr *E) {
240    return E->getKind() == MCExpr::Unary;
241  }
242  static bool classof(const MCUnaryExpr *) { return true; }
243};
244
245/// MCBinaryExpr - Binary assembler expressions.
246class MCBinaryExpr : public MCExpr {
247public:
248  enum Opcode {
249    Add,  ///< Addition.
250    And,  ///< Bitwise and.
251    Div,  ///< Signed division.
252    EQ,   ///< Equality comparison.
253    GT,   ///< Signed greater than comparison (result is either 0 or some
254          ///< target-specific non-zero value)
255    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
256          ///< some target-specific non-zero value).
257    LAnd, ///< Logical and.
258    LOr,  ///< Logical or.
259    LT,   ///< Signed less than comparison (result is either 0 or
260          ///< some target-specific non-zero value).
261    LTE,  ///< Signed less than or equal comparison (result is either 0 or
262          ///< some target-specific non-zero value).
263    Mod,  ///< Signed remainder.
264    Mul,  ///< Multiplication.
265    NE,   ///< Inequality comparison.
266    Or,   ///< Bitwise or.
267    Shl,  ///< Shift left.
268    Shr,  ///< Shift right (arithmetic or logical, depending on target)
269    Sub,  ///< Subtraction.
270    Xor   ///< Bitwise exclusive or.
271  };
272
273private:
274  Opcode Op;
275  const MCExpr *LHS, *RHS;
276
277  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
278    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
279
280public:
281  /// @name Construction
282  /// @{
283
284  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
285                                    const MCExpr *RHS, MCContext &Ctx);
286  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
287                                       MCContext &Ctx) {
288    return Create(Add, LHS, RHS, Ctx);
289  }
290  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
291                                       MCContext &Ctx) {
292    return Create(And, LHS, RHS, Ctx);
293  }
294  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
295                                       MCContext &Ctx) {
296    return Create(Div, LHS, RHS, Ctx);
297  }
298  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
299                                      MCContext &Ctx) {
300    return Create(EQ, LHS, RHS, Ctx);
301  }
302  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
303                                      MCContext &Ctx) {
304    return Create(GT, LHS, RHS, Ctx);
305  }
306  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
307                                       MCContext &Ctx) {
308    return Create(GTE, LHS, RHS, Ctx);
309  }
310  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
311                                        MCContext &Ctx) {
312    return Create(LAnd, LHS, RHS, Ctx);
313  }
314  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
315                                       MCContext &Ctx) {
316    return Create(LOr, LHS, RHS, Ctx);
317  }
318  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
319                                      MCContext &Ctx) {
320    return Create(LT, LHS, RHS, Ctx);
321  }
322  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
323                                       MCContext &Ctx) {
324    return Create(LTE, LHS, RHS, Ctx);
325  }
326  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
327                                       MCContext &Ctx) {
328    return Create(Mod, LHS, RHS, Ctx);
329  }
330  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
331                                       MCContext &Ctx) {
332    return Create(Mul, LHS, RHS, Ctx);
333  }
334  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
335                                      MCContext &Ctx) {
336    return Create(NE, LHS, RHS, Ctx);
337  }
338  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
339                                      MCContext &Ctx) {
340    return Create(Or, LHS, RHS, Ctx);
341  }
342  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
343                                       MCContext &Ctx) {
344    return Create(Shl, LHS, RHS, Ctx);
345  }
346  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
347                                       MCContext &Ctx) {
348    return Create(Shr, LHS, RHS, Ctx);
349  }
350  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
351                                       MCContext &Ctx) {
352    return Create(Sub, LHS, RHS, Ctx);
353  }
354  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
355                                       MCContext &Ctx) {
356    return Create(Xor, LHS, RHS, Ctx);
357  }
358
359  /// @}
360  /// @name Accessors
361  /// @{
362
363  /// getOpcode - Get the kind of this binary expression.
364  Opcode getOpcode() const { return Op; }
365
366  /// getLHS - Get the left-hand side expression of the binary operator.
367  const MCExpr *getLHS() const { return LHS; }
368
369  /// getRHS - Get the right-hand side expression of the binary operator.
370  const MCExpr *getRHS() const { return RHS; }
371
372  /// @}
373
374  static bool classof(const MCExpr *E) {
375    return E->getKind() == MCExpr::Binary;
376  }
377  static bool classof(const MCBinaryExpr *) { return true; }
378};
379
380/// MCTargetExpr - This is an extension point for target-specific MCExpr
381/// subclasses to implement.
382///
383/// NOTE: All subclasses are required to have trivial destructors because
384/// MCExprs are bump pointer allocated and not destructed.
385class MCTargetExpr : public MCExpr {
386  virtual void Anchor();
387protected:
388  MCTargetExpr() : MCExpr(Target) {}
389  virtual ~MCTargetExpr() {}
390public:
391
392  virtual void PrintImpl(raw_ostream &OS) const = 0;
393  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
394                                         const MCAsmLayout *Layout) const = 0;
395
396
397  static bool classof(const MCExpr *E) {
398    return E->getKind() == MCExpr::Target;
399  }
400  static bool classof(const MCTargetExpr *) { return true; }
401};
402
403} // end namespace llvm
404
405#endif
406