MCExpr.h revision 4e815f8a8cae6c846cdca52420046cab902865de 
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  };
139
140private:
141  /// The symbol being referenced.
142  const MCSymbol *Symbol;
143
144  /// The symbol reference modifier.
145  const VariantKind Kind;
146
147  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
148    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
149
150public:
151  /// @name Construction
152  /// @{
153
154  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
155    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
156  }
157
158  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
159                                       MCContext &Ctx);
160  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
161                                       MCContext &Ctx);
162
163  /// CreateTemp - Create a reference to an assembler temporary label with the
164  /// specified name.
165  static const MCSymbolRefExpr *CreateTemp(StringRef Name, VariantKind Kind,
166                                           MCContext &Ctx);
167
168  /// @}
169  /// @name Accessors
170  /// @{
171
172  const MCSymbol &getSymbol() const { return *Symbol; }
173
174  VariantKind getKind() const { return Kind; }
175
176  /// @}
177  /// @name Static Utility Functions
178  /// @{
179
180  static StringRef getVariantKindName(VariantKind Kind);
181
182  static VariantKind getVariantKindForName(StringRef Name);
183
184  /// @}
185
186  static bool classof(const MCExpr *E) {
187    return E->getKind() == MCExpr::SymbolRef;
188  }
189  static bool classof(const MCSymbolRefExpr *) { return true; }
190};
191
192/// MCUnaryExpr - Unary assembler expressions.
193class MCUnaryExpr : public MCExpr {
194public:
195  enum Opcode {
196    LNot,  ///< Logical negation.
197    Minus, ///< Unary minus.
198    Not,   ///< Bitwise negation.
199    Plus   ///< Unary plus.
200  };
201
202private:
203  Opcode Op;
204  const MCExpr *Expr;
205
206  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
207    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
208
209public:
210  /// @name Construction
211  /// @{
212
213  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
214                                   MCContext &Ctx);
215  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
216    return Create(LNot, Expr, Ctx);
217  }
218  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
219    return Create(Minus, Expr, Ctx);
220  }
221  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
222    return Create(Not, Expr, Ctx);
223  }
224  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
225    return Create(Plus, Expr, Ctx);
226  }
227
228  /// @}
229  /// @name Accessors
230  /// @{
231
232  /// getOpcode - Get the kind of this unary expression.
233  Opcode getOpcode() const { return Op; }
234
235  /// getSubExpr - Get the child of this unary expression.
236  const MCExpr *getSubExpr() const { return Expr; }
237
238  /// @}
239
240  static bool classof(const MCExpr *E) {
241    return E->getKind() == MCExpr::Unary;
242  }
243  static bool classof(const MCUnaryExpr *) { return true; }
244};
245
246/// MCBinaryExpr - Binary assembler expressions.
247class MCBinaryExpr : public MCExpr {
248public:
249  enum Opcode {
250    Add,  ///< Addition.
251    And,  ///< Bitwise and.
252    Div,  ///< Signed division.
253    EQ,   ///< Equality comparison.
254    GT,   ///< Signed greater than comparison (result is either 0 or some
255          ///< target-specific non-zero value)
256    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
257          ///< some target-specific non-zero value).
258    LAnd, ///< Logical and.
259    LOr,  ///< Logical or.
260    LT,   ///< Signed less than comparison (result is either 0 or
261          ///< some target-specific non-zero value).
262    LTE,  ///< Signed less than or equal comparison (result is either 0 or
263          ///< some target-specific non-zero value).
264    Mod,  ///< Signed remainder.
265    Mul,  ///< Multiplication.
266    NE,   ///< Inequality comparison.
267    Or,   ///< Bitwise or.
268    Shl,  ///< Shift left.
269    Shr,  ///< Shift right (arithmetic or logical, depending on target)
270    Sub,  ///< Subtraction.
271    Xor   ///< Bitwise exclusive or.
272  };
273
274private:
275  Opcode Op;
276  const MCExpr *LHS, *RHS;
277
278  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
279    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
280
281public:
282  /// @name Construction
283  /// @{
284
285  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
286                                    const MCExpr *RHS, MCContext &Ctx);
287  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
288                                       MCContext &Ctx) {
289    return Create(Add, LHS, RHS, Ctx);
290  }
291  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
292                                       MCContext &Ctx) {
293    return Create(And, LHS, RHS, Ctx);
294  }
295  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
296                                       MCContext &Ctx) {
297    return Create(Div, LHS, RHS, Ctx);
298  }
299  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
300                                      MCContext &Ctx) {
301    return Create(EQ, LHS, RHS, Ctx);
302  }
303  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
304                                      MCContext &Ctx) {
305    return Create(GT, LHS, RHS, Ctx);
306  }
307  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
308                                       MCContext &Ctx) {
309    return Create(GTE, LHS, RHS, Ctx);
310  }
311  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
312                                        MCContext &Ctx) {
313    return Create(LAnd, LHS, RHS, Ctx);
314  }
315  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
316                                       MCContext &Ctx) {
317    return Create(LOr, LHS, RHS, Ctx);
318  }
319  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
320                                      MCContext &Ctx) {
321    return Create(LT, LHS, RHS, Ctx);
322  }
323  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
324                                       MCContext &Ctx) {
325    return Create(LTE, LHS, RHS, Ctx);
326  }
327  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
328                                       MCContext &Ctx) {
329    return Create(Mod, LHS, RHS, Ctx);
330  }
331  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
332                                       MCContext &Ctx) {
333    return Create(Mul, LHS, RHS, Ctx);
334  }
335  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
336                                      MCContext &Ctx) {
337    return Create(NE, LHS, RHS, Ctx);
338  }
339  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
340                                      MCContext &Ctx) {
341    return Create(Or, LHS, RHS, Ctx);
342  }
343  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
344                                       MCContext &Ctx) {
345    return Create(Shl, LHS, RHS, Ctx);
346  }
347  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
348                                       MCContext &Ctx) {
349    return Create(Shr, LHS, RHS, Ctx);
350  }
351  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
352                                       MCContext &Ctx) {
353    return Create(Sub, LHS, RHS, Ctx);
354  }
355  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
356                                       MCContext &Ctx) {
357    return Create(Xor, LHS, RHS, Ctx);
358  }
359
360  /// @}
361  /// @name Accessors
362  /// @{
363
364  /// getOpcode - Get the kind of this binary expression.
365  Opcode getOpcode() const { return Op; }
366
367  /// getLHS - Get the left-hand side expression of the binary operator.
368  const MCExpr *getLHS() const { return LHS; }
369
370  /// getRHS - Get the right-hand side expression of the binary operator.
371  const MCExpr *getRHS() const { return RHS; }
372
373  /// @}
374
375  static bool classof(const MCExpr *E) {
376    return E->getKind() == MCExpr::Binary;
377  }
378  static bool classof(const MCBinaryExpr *) { return true; }
379};
380
381/// MCTargetExpr - This is an extension point for target-specific MCExpr
382/// subclasses to implement.
383///
384/// NOTE: All subclasses are required to have trivial destructors because
385/// MCExprs are bump pointer allocated and not destructed.
386class MCTargetExpr : public MCExpr {
387  virtual void Anchor();
388protected:
389  MCTargetExpr() : MCExpr(Target) {}
390  virtual ~MCTargetExpr() {}
391public:
392
393  virtual void PrintImpl(raw_ostream &OS) const = 0;
394  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
395                                         const MCAsmLayout *Layout) const = 0;
396
397
398  static bool classof(const MCExpr *E) {
399    return E->getKind() == MCExpr::Target;
400  }
401  static bool classof(const MCTargetExpr *) { return true; }
402};
403
404} // end namespace llvm
405
406#endif
407