MCExpr.h revision a0a2f8734cdfc19d44201b791a969bcdda96bb70 
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
46  bool EvaluateAsRelocatableImpl(MCValue &Res, const MCAsmLayout *Layout,
47                                 bool InSet) const;
48public:
49  /// @name Accessors
50  /// @{
51
52  ExprKind getKind() const { return Kind; }
53
54  /// @}
55  /// @name Utility Methods
56  /// @{
57
58  void print(raw_ostream &OS) const;
59  void dump() const;
60
61  /// @}
62  /// @name Expression Evaluation
63  /// @{
64
65  /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
66  ///
67  /// @param Res - The absolute value, if evaluation succeeds.
68  /// @param Layout - The assembler layout object to use for evaluating symbol
69  /// values. If not given, then only non-symbolic expressions will be
70  /// evaluated.
71  /// @result - True on success.
72  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout = 0) const;
73
74  /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
75  /// value, i.e. an expression of the fixed form (a - b + constant).
76  ///
77  /// @param Res - The relocatable value, if evaluation succeeds.
78  /// @param Layout - The assembler layout object to use for evaluating values.
79  /// @result - True on success.
80  bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout *Layout = 0) const;
81
82  /// @}
83
84  static bool classof(const MCExpr *) { return true; }
85};
86
87inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
88  E.print(OS);
89  return OS;
90}
91
92//// MCConstantExpr - Represent a constant integer expression.
93class MCConstantExpr : public MCExpr {
94  int64_t Value;
95
96  explicit MCConstantExpr(int64_t _Value)
97    : MCExpr(MCExpr::Constant), Value(_Value) {}
98
99public:
100  /// @name Construction
101  /// @{
102
103  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
104
105  /// @}
106  /// @name Accessors
107  /// @{
108
109  int64_t getValue() const { return Value; }
110
111  /// @}
112
113  static bool classof(const MCExpr *E) {
114    return E->getKind() == MCExpr::Constant;
115  }
116  static bool classof(const MCConstantExpr *) { return true; }
117};
118
119/// MCSymbolRefExpr - Represent a reference to a symbol from inside an
120/// expression.
121///
122/// A symbol reference in an expression may be a use of a label, a use of an
123/// assembler variable (defined constant), or constitute an implicit definition
124/// of the symbol as external.
125class MCSymbolRefExpr : public MCExpr {
126public:
127  enum VariantKind {
128    VK_None,
129    VK_Invalid,
130
131    VK_GOT,
132    VK_GOTOFF,
133    VK_GOTPCREL,
134    VK_GOTTPOFF,
135    VK_INDNTPOFF,
136    VK_NTPOFF,
137    VK_GOTNTPOFF,
138    VK_PLT,
139    VK_TLSGD,
140    VK_TPOFF,
141    VK_ARM_HI16, // The R_ARM_MOVT_ABS relocation (:upper16: in the asm file)
142    VK_ARM_LO16, // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the asm file)
143    VK_ARM_PLT,  // ARM-style PLT symbol references. i.e., (PLT) instead of @PLT
144    VK_TLVP // Mach-O thread local variable relocation
145  };
146
147private:
148  /// The symbol being referenced.
149  const MCSymbol *Symbol;
150
151  /// The symbol reference modifier.
152  const VariantKind Kind;
153
154  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
155    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
156
157public:
158  /// @name Construction
159  /// @{
160
161  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
162    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
163  }
164
165  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
166                                       MCContext &Ctx);
167  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
168                                       MCContext &Ctx);
169
170  /// @}
171  /// @name Accessors
172  /// @{
173
174  const MCSymbol &getSymbol() const { return *Symbol; }
175
176  VariantKind getKind() const { return Kind; }
177
178  /// @}
179  /// @name Static Utility Functions
180  /// @{
181
182  static StringRef getVariantKindName(VariantKind Kind);
183
184  static VariantKind getVariantKindForName(StringRef Name);
185
186  /// @}
187
188  static bool classof(const MCExpr *E) {
189    return E->getKind() == MCExpr::SymbolRef;
190  }
191  static bool classof(const MCSymbolRefExpr *) { return true; }
192};
193
194/// MCUnaryExpr - Unary assembler expressions.
195class MCUnaryExpr : public MCExpr {
196public:
197  enum Opcode {
198    LNot,  ///< Logical negation.
199    Minus, ///< Unary minus.
200    Not,   ///< Bitwise negation.
201    Plus   ///< Unary plus.
202  };
203
204private:
205  Opcode Op;
206  const MCExpr *Expr;
207
208  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
209    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
210
211public:
212  /// @name Construction
213  /// @{
214
215  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
216                                   MCContext &Ctx);
217  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
218    return Create(LNot, Expr, Ctx);
219  }
220  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
221    return Create(Minus, Expr, Ctx);
222  }
223  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
224    return Create(Not, Expr, Ctx);
225  }
226  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
227    return Create(Plus, Expr, Ctx);
228  }
229
230  /// @}
231  /// @name Accessors
232  /// @{
233
234  /// getOpcode - Get the kind of this unary expression.
235  Opcode getOpcode() const { return Op; }
236
237  /// getSubExpr - Get the child of this unary expression.
238  const MCExpr *getSubExpr() const { return Expr; }
239
240  /// @}
241
242  static bool classof(const MCExpr *E) {
243    return E->getKind() == MCExpr::Unary;
244  }
245  static bool classof(const MCUnaryExpr *) { return true; }
246};
247
248/// MCBinaryExpr - Binary assembler expressions.
249class MCBinaryExpr : public MCExpr {
250public:
251  enum Opcode {
252    Add,  ///< Addition.
253    And,  ///< Bitwise and.
254    Div,  ///< Signed division.
255    EQ,   ///< Equality comparison.
256    GT,   ///< Signed greater than comparison (result is either 0 or some
257          ///< target-specific non-zero value)
258    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
259          ///< some target-specific non-zero value).
260    LAnd, ///< Logical and.
261    LOr,  ///< Logical or.
262    LT,   ///< Signed less than comparison (result is either 0 or
263          ///< some target-specific non-zero value).
264    LTE,  ///< Signed less than or equal comparison (result is either 0 or
265          ///< some target-specific non-zero value).
266    Mod,  ///< Signed remainder.
267    Mul,  ///< Multiplication.
268    NE,   ///< Inequality comparison.
269    Or,   ///< Bitwise or.
270    Shl,  ///< Shift left.
271    Shr,  ///< Shift right (arithmetic or logical, depending on target)
272    Sub,  ///< Subtraction.
273    Xor   ///< Bitwise exclusive or.
274  };
275
276private:
277  Opcode Op;
278  const MCExpr *LHS, *RHS;
279
280  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
281    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
282
283public:
284  /// @name Construction
285  /// @{
286
287  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
288                                    const MCExpr *RHS, MCContext &Ctx);
289  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
290                                       MCContext &Ctx) {
291    return Create(Add, LHS, RHS, Ctx);
292  }
293  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
294                                       MCContext &Ctx) {
295    return Create(And, LHS, RHS, Ctx);
296  }
297  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
298                                       MCContext &Ctx) {
299    return Create(Div, LHS, RHS, Ctx);
300  }
301  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
302                                      MCContext &Ctx) {
303    return Create(EQ, LHS, RHS, Ctx);
304  }
305  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
306                                      MCContext &Ctx) {
307    return Create(GT, LHS, RHS, Ctx);
308  }
309  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
310                                       MCContext &Ctx) {
311    return Create(GTE, LHS, RHS, Ctx);
312  }
313  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
314                                        MCContext &Ctx) {
315    return Create(LAnd, LHS, RHS, Ctx);
316  }
317  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
318                                       MCContext &Ctx) {
319    return Create(LOr, LHS, RHS, Ctx);
320  }
321  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
322                                      MCContext &Ctx) {
323    return Create(LT, LHS, RHS, Ctx);
324  }
325  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
326                                       MCContext &Ctx) {
327    return Create(LTE, LHS, RHS, Ctx);
328  }
329  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
330                                       MCContext &Ctx) {
331    return Create(Mod, LHS, RHS, Ctx);
332  }
333  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
334                                       MCContext &Ctx) {
335    return Create(Mul, LHS, RHS, Ctx);
336  }
337  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
338                                      MCContext &Ctx) {
339    return Create(NE, LHS, RHS, Ctx);
340  }
341  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
342                                      MCContext &Ctx) {
343    return Create(Or, LHS, RHS, Ctx);
344  }
345  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
346                                       MCContext &Ctx) {
347    return Create(Shl, LHS, RHS, Ctx);
348  }
349  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
350                                       MCContext &Ctx) {
351    return Create(Shr, LHS, RHS, Ctx);
352  }
353  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
354                                       MCContext &Ctx) {
355    return Create(Sub, LHS, RHS, Ctx);
356  }
357  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
358                                       MCContext &Ctx) {
359    return Create(Xor, LHS, RHS, Ctx);
360  }
361
362  /// @}
363  /// @name Accessors
364  /// @{
365
366  /// getOpcode - Get the kind of this binary expression.
367  Opcode getOpcode() const { return Op; }
368
369  /// getLHS - Get the left-hand side expression of the binary operator.
370  const MCExpr *getLHS() const { return LHS; }
371
372  /// getRHS - Get the right-hand side expression of the binary operator.
373  const MCExpr *getRHS() const { return RHS; }
374
375  /// @}
376
377  static bool classof(const MCExpr *E) {
378    return E->getKind() == MCExpr::Binary;
379  }
380  static bool classof(const MCBinaryExpr *) { return true; }
381};
382
383/// MCTargetExpr - This is an extension point for target-specific MCExpr
384/// subclasses to implement.
385///
386/// NOTE: All subclasses are required to have trivial destructors because
387/// MCExprs are bump pointer allocated and not destructed.
388class MCTargetExpr : public MCExpr {
389  virtual void Anchor();
390protected:
391  MCTargetExpr() : MCExpr(Target) {}
392  virtual ~MCTargetExpr() {}
393public:
394
395  virtual void PrintImpl(raw_ostream &OS) const = 0;
396  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
397                                         const MCAsmLayout *Layout) const = 0;
398
399
400  static bool classof(const MCExpr *E) {
401    return E->getKind() == MCExpr::Target;
402  }
403  static bool classof(const MCTargetExpr *) { return true; }
404};
405
406} // end namespace llvm
407
408#endif
409