MCExpr.h revision 036c130e90eb5c93b0dc0a70ad07b9343623c2a8 
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 MCContext;
19class MCSymbol;
20class MCValue;
21class raw_ostream;
22class StringRef;
23
24/// MCExpr - Base class for the full range of assembler expressions which are
25/// needed for parsing.
26class MCExpr {
27public:
28  enum ExprKind {
29    Binary,    ///< Binary expressions.
30    Constant,  ///< Constant expressions.
31    SymbolRef, ///< References to labels and assigned expressions.
32    Unary,     ///< Unary expressions.
33    Target     ///< Target specific expression.
34  };
35
36private:
37  ExprKind Kind;
38
39  MCExpr(const MCExpr&); // DO NOT IMPLEMENT
40  void operator=(const MCExpr&); // DO NOT IMPLEMENT
41
42protected:
43  MCExpr(ExprKind _Kind) : Kind(_Kind) {}
44
45public:
46  /// @name Accessors
47  /// @{
48
49  ExprKind getKind() const { return Kind; }
50
51  /// @}
52  /// @name Utility Methods
53  /// @{
54
55  void print(raw_ostream &OS) const;
56  void dump() const;
57
58  /// @}
59  /// @name Expression Evaluation
60  /// @{
61
62  /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
63  ///
64  /// @param Res - The absolute value, if evaluation succeeds.
65  /// @result - True on success.
66  bool EvaluateAsAbsolute(int64_t &Res) const;
67
68  /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
69  /// value, i.e. an expression of the fixed form (a - b + constant).
70  ///
71  /// @param Res - The relocatable value, if evaluation succeeds.
72  /// @result - True on success.
73  bool EvaluateAsRelocatable(MCValue &Res) const;
74
75  /// @}
76
77  static bool classof(const MCExpr *) { return true; }
78};
79
80inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
81  E.print(OS);
82  return OS;
83}
84
85//// MCConstantExpr - Represent a constant integer expression.
86class MCConstantExpr : public MCExpr {
87  int64_t Value;
88
89  MCConstantExpr(int64_t _Value)
90    : MCExpr(MCExpr::Constant), Value(_Value) {}
91
92public:
93  /// @name Construction
94  /// @{
95
96  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
97
98  /// @}
99  /// @name Accessors
100  /// @{
101
102  int64_t getValue() const { return Value; }
103
104  /// @}
105
106  static bool classof(const MCExpr *E) {
107    return E->getKind() == MCExpr::Constant;
108  }
109  static bool classof(const MCConstantExpr *) { return true; }
110};
111
112/// MCSymbolRefExpr - Represent a reference to a symbol from inside an
113/// expression.
114///
115/// A symbol reference in an expression may be a use of a label, a use of an
116/// assembler variable (defined constant), or constitute an implicit definition
117/// of the symbol as external.
118class MCSymbolRefExpr : public MCExpr {
119  const MCSymbol *Symbol;
120
121  MCSymbolRefExpr(const MCSymbol *_Symbol)
122    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol) {}
123
124public:
125  /// @name Construction
126  /// @{
127
128  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx);
129  static const MCSymbolRefExpr *Create(StringRef Name, MCContext &Ctx);
130
131  /// @}
132  /// @name Accessors
133  /// @{
134
135  const MCSymbol &getSymbol() const { return *Symbol; }
136
137  /// @}
138
139  static bool classof(const MCExpr *E) {
140    return E->getKind() == MCExpr::SymbolRef;
141  }
142  static bool classof(const MCSymbolRefExpr *) { return true; }
143};
144
145/// MCUnaryExpr - Unary assembler expressions.
146class MCUnaryExpr : public MCExpr {
147public:
148  enum Opcode {
149    LNot,  ///< Logical negation.
150    Minus, ///< Unary minus.
151    Not,   ///< Bitwise negation.
152    Plus   ///< Unary plus.
153  };
154
155private:
156  Opcode Op;
157  const MCExpr *Expr;
158
159  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
160    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
161
162public:
163  /// @name Construction
164  /// @{
165
166  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
167                                   MCContext &Ctx);
168  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
169    return Create(LNot, Expr, Ctx);
170  }
171  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
172    return Create(Minus, Expr, Ctx);
173  }
174  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
175    return Create(Not, Expr, Ctx);
176  }
177  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
178    return Create(Plus, Expr, Ctx);
179  }
180
181  /// @}
182  /// @name Accessors
183  /// @{
184
185  /// getOpcode - Get the kind of this unary expression.
186  Opcode getOpcode() const { return Op; }
187
188  /// getSubExpr - Get the child of this unary expression.
189  const MCExpr *getSubExpr() const { return Expr; }
190
191  /// @}
192
193  static bool classof(const MCExpr *E) {
194    return E->getKind() == MCExpr::Unary;
195  }
196  static bool classof(const MCUnaryExpr *) { return true; }
197};
198
199/// MCBinaryExpr - Binary assembler expressions.
200class MCBinaryExpr : public MCExpr {
201public:
202  enum Opcode {
203    Add,  ///< Addition.
204    And,  ///< Bitwise and.
205    Div,  ///< Signed division.
206    EQ,   ///< Equality comparison.
207    GT,   ///< Signed greater than comparison (result is either 0 or some
208          ///< target-specific non-zero value)
209    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
210          ///< some target-specific non-zero value).
211    LAnd, ///< Logical and.
212    LOr,  ///< Logical or.
213    LT,   ///< Signed less than comparison (result is either 0 or
214          ///< some target-specific non-zero value).
215    LTE,  ///< Signed less than or equal comparison (result is either 0 or
216          ///< some target-specific non-zero value).
217    Mod,  ///< Signed remainder.
218    Mul,  ///< Multiplication.
219    NE,   ///< Inequality comparison.
220    Or,   ///< Bitwise or.
221    Shl,  ///< Shift left.
222    Shr,  ///< Shift right (arithmetic or logical, depending on target)
223    Sub,  ///< Subtraction.
224    Xor   ///< Bitwise exclusive or.
225  };
226
227private:
228  Opcode Op;
229  const MCExpr *LHS, *RHS;
230
231  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
232    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
233
234public:
235  /// @name Construction
236  /// @{
237
238  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
239                                    const MCExpr *RHS, MCContext &Ctx);
240  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
241                                       MCContext &Ctx) {
242    return Create(Add, LHS, RHS, Ctx);
243  }
244  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
245                                       MCContext &Ctx) {
246    return Create(And, LHS, RHS, Ctx);
247  }
248  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
249                                       MCContext &Ctx) {
250    return Create(Div, LHS, RHS, Ctx);
251  }
252  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
253                                      MCContext &Ctx) {
254    return Create(EQ, LHS, RHS, Ctx);
255  }
256  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
257                                      MCContext &Ctx) {
258    return Create(GT, LHS, RHS, Ctx);
259  }
260  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
261                                       MCContext &Ctx) {
262    return Create(GTE, LHS, RHS, Ctx);
263  }
264  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
265                                        MCContext &Ctx) {
266    return Create(LAnd, LHS, RHS, Ctx);
267  }
268  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
269                                       MCContext &Ctx) {
270    return Create(LOr, LHS, RHS, Ctx);
271  }
272  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
273                                      MCContext &Ctx) {
274    return Create(LT, LHS, RHS, Ctx);
275  }
276  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
277                                       MCContext &Ctx) {
278    return Create(LTE, LHS, RHS, Ctx);
279  }
280  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
281                                       MCContext &Ctx) {
282    return Create(Mod, LHS, RHS, Ctx);
283  }
284  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
285                                       MCContext &Ctx) {
286    return Create(Mul, LHS, RHS, Ctx);
287  }
288  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
289                                      MCContext &Ctx) {
290    return Create(NE, LHS, RHS, Ctx);
291  }
292  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
293                                      MCContext &Ctx) {
294    return Create(Or, LHS, RHS, Ctx);
295  }
296  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
297                                       MCContext &Ctx) {
298    return Create(Shl, LHS, RHS, Ctx);
299  }
300  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
301                                       MCContext &Ctx) {
302    return Create(Shr, LHS, RHS, Ctx);
303  }
304  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
305                                       MCContext &Ctx) {
306    return Create(Sub, LHS, RHS, Ctx);
307  }
308  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
309                                       MCContext &Ctx) {
310    return Create(Xor, LHS, RHS, Ctx);
311  }
312
313  /// @}
314  /// @name Accessors
315  /// @{
316
317  /// getOpcode - Get the kind of this binary expression.
318  Opcode getOpcode() const { return Op; }
319
320  /// getLHS - Get the left-hand side expression of the binary operator.
321  const MCExpr *getLHS() const { return LHS; }
322
323  /// getRHS - Get the right-hand side expression of the binary operator.
324  const MCExpr *getRHS() const { return RHS; }
325
326  /// @}
327
328  static bool classof(const MCExpr *E) {
329    return E->getKind() == MCExpr::Binary;
330  }
331  static bool classof(const MCBinaryExpr *) { return true; }
332};
333
334/// MCTargetExpr - This is an extension point for target-specific MCExpr
335/// subclasses to implement.
336///
337/// NOTE: All subclasses are required to have trivial destructors because
338/// MCExprs are bump pointer allocated and not destructed.
339class MCTargetExpr : public MCExpr {
340  virtual void Anchor();
341protected:
342  MCTargetExpr() : MCExpr(Target) {}
343
344public:
345
346  virtual void PrintImpl(raw_ostream &OS) const = 0;
347  virtual bool EvaluateAsRelocatableImpl(MCValue &Res) const = 0;
348
349
350  static bool classof(const MCExpr *E) {
351    return E->getKind() == MCExpr::Target;
352  }
353  static bool classof(const MCTargetExpr *) { return true; }
354};
355
356} // end namespace llvm
357
358#endif
359