MCExpr.h revision a0e36d55c495b3325805c659ac365b5faea84e34 
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 {
124  const MCSymbol *Symbol;
125
126  explicit MCSymbolRefExpr(const MCSymbol *_Symbol)
127    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol) {}
128
129public:
130  /// @name Construction
131  /// @{
132
133  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx);
134  static const MCSymbolRefExpr *Create(StringRef Name, MCContext &Ctx);
135
136  /// CreateTemp - Create a reference to an assembler temporary label with the
137  /// specified name.
138  static const MCSymbolRefExpr *CreateTemp(StringRef Name, MCContext &Ctx);
139
140  /// @}
141  /// @name Accessors
142  /// @{
143
144  const MCSymbol &getSymbol() const { return *Symbol; }
145
146  /// @}
147
148  static bool classof(const MCExpr *E) {
149    return E->getKind() == MCExpr::SymbolRef;
150  }
151  static bool classof(const MCSymbolRefExpr *) { return true; }
152};
153
154/// MCUnaryExpr - Unary assembler expressions.
155class MCUnaryExpr : public MCExpr {
156public:
157  enum Opcode {
158    LNot,  ///< Logical negation.
159    Minus, ///< Unary minus.
160    Not,   ///< Bitwise negation.
161    Plus   ///< Unary plus.
162  };
163
164private:
165  Opcode Op;
166  const MCExpr *Expr;
167
168  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
169    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
170
171public:
172  /// @name Construction
173  /// @{
174
175  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
176                                   MCContext &Ctx);
177  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
178    return Create(LNot, Expr, Ctx);
179  }
180  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
181    return Create(Minus, Expr, Ctx);
182  }
183  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
184    return Create(Not, Expr, Ctx);
185  }
186  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
187    return Create(Plus, Expr, Ctx);
188  }
189
190  /// @}
191  /// @name Accessors
192  /// @{
193
194  /// getOpcode - Get the kind of this unary expression.
195  Opcode getOpcode() const { return Op; }
196
197  /// getSubExpr - Get the child of this unary expression.
198  const MCExpr *getSubExpr() const { return Expr; }
199
200  /// @}
201
202  static bool classof(const MCExpr *E) {
203    return E->getKind() == MCExpr::Unary;
204  }
205  static bool classof(const MCUnaryExpr *) { return true; }
206};
207
208/// MCBinaryExpr - Binary assembler expressions.
209class MCBinaryExpr : public MCExpr {
210public:
211  enum Opcode {
212    Add,  ///< Addition.
213    And,  ///< Bitwise and.
214    Div,  ///< Signed division.
215    EQ,   ///< Equality comparison.
216    GT,   ///< Signed greater than comparison (result is either 0 or some
217          ///< target-specific non-zero value)
218    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
219          ///< some target-specific non-zero value).
220    LAnd, ///< Logical and.
221    LOr,  ///< Logical or.
222    LT,   ///< Signed less than comparison (result is either 0 or
223          ///< some target-specific non-zero value).
224    LTE,  ///< Signed less than or equal comparison (result is either 0 or
225          ///< some target-specific non-zero value).
226    Mod,  ///< Signed remainder.
227    Mul,  ///< Multiplication.
228    NE,   ///< Inequality comparison.
229    Or,   ///< Bitwise or.
230    Shl,  ///< Shift left.
231    Shr,  ///< Shift right (arithmetic or logical, depending on target)
232    Sub,  ///< Subtraction.
233    Xor   ///< Bitwise exclusive or.
234  };
235
236private:
237  Opcode Op;
238  const MCExpr *LHS, *RHS;
239
240  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
241    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
242
243public:
244  /// @name Construction
245  /// @{
246
247  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
248                                    const MCExpr *RHS, MCContext &Ctx);
249  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
250                                       MCContext &Ctx) {
251    return Create(Add, LHS, RHS, Ctx);
252  }
253  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
254                                       MCContext &Ctx) {
255    return Create(And, LHS, RHS, Ctx);
256  }
257  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
258                                       MCContext &Ctx) {
259    return Create(Div, LHS, RHS, Ctx);
260  }
261  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
262                                      MCContext &Ctx) {
263    return Create(EQ, LHS, RHS, Ctx);
264  }
265  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
266                                      MCContext &Ctx) {
267    return Create(GT, LHS, RHS, Ctx);
268  }
269  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
270                                       MCContext &Ctx) {
271    return Create(GTE, LHS, RHS, Ctx);
272  }
273  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
274                                        MCContext &Ctx) {
275    return Create(LAnd, LHS, RHS, Ctx);
276  }
277  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
278                                       MCContext &Ctx) {
279    return Create(LOr, LHS, RHS, Ctx);
280  }
281  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
282                                      MCContext &Ctx) {
283    return Create(LT, LHS, RHS, Ctx);
284  }
285  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
286                                       MCContext &Ctx) {
287    return Create(LTE, LHS, RHS, Ctx);
288  }
289  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
290                                       MCContext &Ctx) {
291    return Create(Mod, LHS, RHS, Ctx);
292  }
293  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
294                                       MCContext &Ctx) {
295    return Create(Mul, LHS, RHS, Ctx);
296  }
297  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
298                                      MCContext &Ctx) {
299    return Create(NE, LHS, RHS, Ctx);
300  }
301  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
302                                      MCContext &Ctx) {
303    return Create(Or, LHS, RHS, Ctx);
304  }
305  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
306                                       MCContext &Ctx) {
307    return Create(Shl, LHS, RHS, Ctx);
308  }
309  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
310                                       MCContext &Ctx) {
311    return Create(Shr, LHS, RHS, Ctx);
312  }
313  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
314                                       MCContext &Ctx) {
315    return Create(Sub, LHS, RHS, Ctx);
316  }
317  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
318                                       MCContext &Ctx) {
319    return Create(Xor, LHS, RHS, Ctx);
320  }
321
322  /// @}
323  /// @name Accessors
324  /// @{
325
326  /// getOpcode - Get the kind of this binary expression.
327  Opcode getOpcode() const { return Op; }
328
329  /// getLHS - Get the left-hand side expression of the binary operator.
330  const MCExpr *getLHS() const { return LHS; }
331
332  /// getRHS - Get the right-hand side expression of the binary operator.
333  const MCExpr *getRHS() const { return RHS; }
334
335  /// @}
336
337  static bool classof(const MCExpr *E) {
338    return E->getKind() == MCExpr::Binary;
339  }
340  static bool classof(const MCBinaryExpr *) { return true; }
341};
342
343/// MCTargetExpr - This is an extension point for target-specific MCExpr
344/// subclasses to implement.
345///
346/// NOTE: All subclasses are required to have trivial destructors because
347/// MCExprs are bump pointer allocated and not destructed.
348class MCTargetExpr : public MCExpr {
349  virtual void Anchor();
350protected:
351  MCTargetExpr() : MCExpr(Target) {}
352  virtual ~MCTargetExpr() {}
353public:
354
355  virtual void PrintImpl(raw_ostream &OS) const = 0;
356  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
357                                         const MCAsmLayout *Layout) const = 0;
358
359
360  static bool classof(const MCExpr *E) {
361    return E->getKind() == MCExpr::Target;
362  }
363  static bool classof(const MCTargetExpr *) { return true; }
364};
365
366} // end namespace llvm
367
368#endif
369