MCExpr.h revision 96ac5156cadde7e4494990d5b4f873e76787a370 
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_TLVP // Mach-O thread local variable relocation
141  };
142
143private:
144  /// The symbol being referenced.
145  const MCSymbol *Symbol;
146
147  /// The symbol reference modifier.
148  const VariantKind Kind;
149
150  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
151    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
152
153public:
154  /// @name Construction
155  /// @{
156
157  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
158    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
159  }
160
161  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
162                                       MCContext &Ctx);
163  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
164                                       MCContext &Ctx);
165
166  /// @}
167  /// @name Accessors
168  /// @{
169
170  const MCSymbol &getSymbol() const { return *Symbol; }
171
172  VariantKind getKind() const { return Kind; }
173
174  /// @}
175  /// @name Static Utility Functions
176  /// @{
177
178  static StringRef getVariantKindName(VariantKind Kind);
179
180  static VariantKind getVariantKindForName(StringRef Name);
181
182  /// @}
183
184  static bool classof(const MCExpr *E) {
185    return E->getKind() == MCExpr::SymbolRef;
186  }
187  static bool classof(const MCSymbolRefExpr *) { return true; }
188};
189
190/// MCUnaryExpr - Unary assembler expressions.
191class MCUnaryExpr : public MCExpr {
192public:
193  enum Opcode {
194    LNot,  ///< Logical negation.
195    Minus, ///< Unary minus.
196    Not,   ///< Bitwise negation.
197    Plus   ///< Unary plus.
198  };
199
200private:
201  Opcode Op;
202  const MCExpr *Expr;
203
204  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
205    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
206
207public:
208  /// @name Construction
209  /// @{
210
211  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
212                                   MCContext &Ctx);
213  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
214    return Create(LNot, Expr, Ctx);
215  }
216  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
217    return Create(Minus, Expr, Ctx);
218  }
219  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
220    return Create(Not, Expr, Ctx);
221  }
222  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
223    return Create(Plus, Expr, Ctx);
224  }
225
226  /// @}
227  /// @name Accessors
228  /// @{
229
230  /// getOpcode - Get the kind of this unary expression.
231  Opcode getOpcode() const { return Op; }
232
233  /// getSubExpr - Get the child of this unary expression.
234  const MCExpr *getSubExpr() const { return Expr; }
235
236  /// @}
237
238  static bool classof(const MCExpr *E) {
239    return E->getKind() == MCExpr::Unary;
240  }
241  static bool classof(const MCUnaryExpr *) { return true; }
242};
243
244/// MCBinaryExpr - Binary assembler expressions.
245class MCBinaryExpr : public MCExpr {
246public:
247  enum Opcode {
248    Add,  ///< Addition.
249    And,  ///< Bitwise and.
250    Div,  ///< Signed division.
251    EQ,   ///< Equality comparison.
252    GT,   ///< Signed greater than comparison (result is either 0 or some
253          ///< target-specific non-zero value)
254    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
255          ///< some target-specific non-zero value).
256    LAnd, ///< Logical and.
257    LOr,  ///< Logical or.
258    LT,   ///< Signed less than comparison (result is either 0 or
259          ///< some target-specific non-zero value).
260    LTE,  ///< Signed less than or equal comparison (result is either 0 or
261          ///< some target-specific non-zero value).
262    Mod,  ///< Signed remainder.
263    Mul,  ///< Multiplication.
264    NE,   ///< Inequality comparison.
265    Or,   ///< Bitwise or.
266    Shl,  ///< Shift left.
267    Shr,  ///< Shift right (arithmetic or logical, depending on target)
268    Sub,  ///< Subtraction.
269    Xor   ///< Bitwise exclusive or.
270  };
271
272private:
273  Opcode Op;
274  const MCExpr *LHS, *RHS;
275
276  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
277    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
278
279public:
280  /// @name Construction
281  /// @{
282
283  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
284                                    const MCExpr *RHS, MCContext &Ctx);
285  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
286                                       MCContext &Ctx) {
287    return Create(Add, LHS, RHS, Ctx);
288  }
289  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
290                                       MCContext &Ctx) {
291    return Create(And, LHS, RHS, Ctx);
292  }
293  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
294                                       MCContext &Ctx) {
295    return Create(Div, LHS, RHS, Ctx);
296  }
297  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
298                                      MCContext &Ctx) {
299    return Create(EQ, LHS, RHS, Ctx);
300  }
301  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
302                                      MCContext &Ctx) {
303    return Create(GT, LHS, RHS, Ctx);
304  }
305  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
306                                       MCContext &Ctx) {
307    return Create(GTE, LHS, RHS, Ctx);
308  }
309  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
310                                        MCContext &Ctx) {
311    return Create(LAnd, LHS, RHS, Ctx);
312  }
313  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
314                                       MCContext &Ctx) {
315    return Create(LOr, LHS, RHS, Ctx);
316  }
317  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
318                                      MCContext &Ctx) {
319    return Create(LT, LHS, RHS, Ctx);
320  }
321  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
322                                       MCContext &Ctx) {
323    return Create(LTE, LHS, RHS, Ctx);
324  }
325  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
326                                       MCContext &Ctx) {
327    return Create(Mod, LHS, RHS, Ctx);
328  }
329  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
330                                       MCContext &Ctx) {
331    return Create(Mul, LHS, RHS, Ctx);
332  }
333  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
334                                      MCContext &Ctx) {
335    return Create(NE, LHS, RHS, Ctx);
336  }
337  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
338                                      MCContext &Ctx) {
339    return Create(Or, LHS, RHS, Ctx);
340  }
341  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
342                                       MCContext &Ctx) {
343    return Create(Shl, LHS, RHS, Ctx);
344  }
345  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
346                                       MCContext &Ctx) {
347    return Create(Shr, LHS, RHS, Ctx);
348  }
349  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
350                                       MCContext &Ctx) {
351    return Create(Sub, LHS, RHS, Ctx);
352  }
353  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
354                                       MCContext &Ctx) {
355    return Create(Xor, LHS, RHS, Ctx);
356  }
357
358  /// @}
359  /// @name Accessors
360  /// @{
361
362  /// getOpcode - Get the kind of this binary expression.
363  Opcode getOpcode() const { return Op; }
364
365  /// getLHS - Get the left-hand side expression of the binary operator.
366  const MCExpr *getLHS() const { return LHS; }
367
368  /// getRHS - Get the right-hand side expression of the binary operator.
369  const MCExpr *getRHS() const { return RHS; }
370
371  /// @}
372
373  static bool classof(const MCExpr *E) {
374    return E->getKind() == MCExpr::Binary;
375  }
376  static bool classof(const MCBinaryExpr *) { return true; }
377};
378
379/// MCTargetExpr - This is an extension point for target-specific MCExpr
380/// subclasses to implement.
381///
382/// NOTE: All subclasses are required to have trivial destructors because
383/// MCExprs are bump pointer allocated and not destructed.
384class MCTargetExpr : public MCExpr {
385  virtual void Anchor();
386protected:
387  MCTargetExpr() : MCExpr(Target) {}
388  virtual ~MCTargetExpr() {}
389public:
390
391  virtual void PrintImpl(raw_ostream &OS) const = 0;
392  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
393                                         const MCAsmLayout *Layout) const = 0;
394
395
396  static bool classof(const MCExpr *E) {
397    return E->getKind() == MCExpr::Target;
398  }
399  static bool classof(const MCTargetExpr *) { return true; }
400};
401
402} // end namespace llvm
403
404#endif
405