MCExpr.h revision a264f72d3fb9dec1427480fcf17ef3c746ea723a 
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_TLSLDM,
141    VK_TPOFF,
142    VK_ARM_HI16, // The R_ARM_MOVT_ABS relocation (:upper16: in the asm file)
143    VK_ARM_LO16, // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the asm file)
144    VK_ARM_PLT,  // ARM-style PLT symbol references. i.e., (PLT) instead of @PLT
145    VK_TLVP // Mach-O thread local variable relocation
146  };
147
148private:
149  /// The symbol being referenced.
150  const MCSymbol *Symbol;
151
152  /// The symbol reference modifier.
153  const VariantKind Kind;
154
155  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
156    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
157
158public:
159  /// @name Construction
160  /// @{
161
162  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
163    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
164  }
165
166  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
167                                       MCContext &Ctx);
168  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
169                                       MCContext &Ctx);
170
171  /// @}
172  /// @name Accessors
173  /// @{
174
175  const MCSymbol &getSymbol() const { return *Symbol; }
176
177  VariantKind getKind() const { return Kind; }
178
179  /// @}
180  /// @name Static Utility Functions
181  /// @{
182
183  static StringRef getVariantKindName(VariantKind Kind);
184
185  static VariantKind getVariantKindForName(StringRef Name);
186
187  /// @}
188
189  static bool classof(const MCExpr *E) {
190    return E->getKind() == MCExpr::SymbolRef;
191  }
192  static bool classof(const MCSymbolRefExpr *) { return true; }
193};
194
195/// MCUnaryExpr - Unary assembler expressions.
196class MCUnaryExpr : public MCExpr {
197public:
198  enum Opcode {
199    LNot,  ///< Logical negation.
200    Minus, ///< Unary minus.
201    Not,   ///< Bitwise negation.
202    Plus   ///< Unary plus.
203  };
204
205private:
206  Opcode Op;
207  const MCExpr *Expr;
208
209  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
210    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
211
212public:
213  /// @name Construction
214  /// @{
215
216  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
217                                   MCContext &Ctx);
218  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
219    return Create(LNot, Expr, Ctx);
220  }
221  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
222    return Create(Minus, Expr, Ctx);
223  }
224  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
225    return Create(Not, Expr, Ctx);
226  }
227  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
228    return Create(Plus, Expr, Ctx);
229  }
230
231  /// @}
232  /// @name Accessors
233  /// @{
234
235  /// getOpcode - Get the kind of this unary expression.
236  Opcode getOpcode() const { return Op; }
237
238  /// getSubExpr - Get the child of this unary expression.
239  const MCExpr *getSubExpr() const { return Expr; }
240
241  /// @}
242
243  static bool classof(const MCExpr *E) {
244    return E->getKind() == MCExpr::Unary;
245  }
246  static bool classof(const MCUnaryExpr *) { return true; }
247};
248
249/// MCBinaryExpr - Binary assembler expressions.
250class MCBinaryExpr : public MCExpr {
251public:
252  enum Opcode {
253    Add,  ///< Addition.
254    And,  ///< Bitwise and.
255    Div,  ///< Signed division.
256    EQ,   ///< Equality comparison.
257    GT,   ///< Signed greater than comparison (result is either 0 or some
258          ///< target-specific non-zero value)
259    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
260          ///< some target-specific non-zero value).
261    LAnd, ///< Logical and.
262    LOr,  ///< Logical or.
263    LT,   ///< Signed less than comparison (result is either 0 or
264          ///< some target-specific non-zero value).
265    LTE,  ///< Signed less than or equal comparison (result is either 0 or
266          ///< some target-specific non-zero value).
267    Mod,  ///< Signed remainder.
268    Mul,  ///< Multiplication.
269    NE,   ///< Inequality comparison.
270    Or,   ///< Bitwise or.
271    Shl,  ///< Shift left.
272    Shr,  ///< Shift right (arithmetic or logical, depending on target)
273    Sub,  ///< Subtraction.
274    Xor   ///< Bitwise exclusive or.
275  };
276
277private:
278  Opcode Op;
279  const MCExpr *LHS, *RHS;
280
281  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
282    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
283
284public:
285  /// @name Construction
286  /// @{
287
288  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
289                                    const MCExpr *RHS, MCContext &Ctx);
290  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
291                                       MCContext &Ctx) {
292    return Create(Add, LHS, RHS, Ctx);
293  }
294  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
295                                       MCContext &Ctx) {
296    return Create(And, LHS, RHS, Ctx);
297  }
298  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
299                                       MCContext &Ctx) {
300    return Create(Div, LHS, RHS, Ctx);
301  }
302  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
303                                      MCContext &Ctx) {
304    return Create(EQ, LHS, RHS, Ctx);
305  }
306  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
307                                      MCContext &Ctx) {
308    return Create(GT, LHS, RHS, Ctx);
309  }
310  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
311                                       MCContext &Ctx) {
312    return Create(GTE, LHS, RHS, Ctx);
313  }
314  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
315                                        MCContext &Ctx) {
316    return Create(LAnd, LHS, RHS, Ctx);
317  }
318  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
319                                       MCContext &Ctx) {
320    return Create(LOr, LHS, RHS, Ctx);
321  }
322  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
323                                      MCContext &Ctx) {
324    return Create(LT, LHS, RHS, Ctx);
325  }
326  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
327                                       MCContext &Ctx) {
328    return Create(LTE, LHS, RHS, Ctx);
329  }
330  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
331                                       MCContext &Ctx) {
332    return Create(Mod, LHS, RHS, Ctx);
333  }
334  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
335                                       MCContext &Ctx) {
336    return Create(Mul, LHS, RHS, Ctx);
337  }
338  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
339                                      MCContext &Ctx) {
340    return Create(NE, LHS, RHS, Ctx);
341  }
342  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
343                                      MCContext &Ctx) {
344    return Create(Or, LHS, RHS, Ctx);
345  }
346  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
347                                       MCContext &Ctx) {
348    return Create(Shl, LHS, RHS, Ctx);
349  }
350  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
351                                       MCContext &Ctx) {
352    return Create(Shr, LHS, RHS, Ctx);
353  }
354  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
355                                       MCContext &Ctx) {
356    return Create(Sub, LHS, RHS, Ctx);
357  }
358  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
359                                       MCContext &Ctx) {
360    return Create(Xor, LHS, RHS, Ctx);
361  }
362
363  /// @}
364  /// @name Accessors
365  /// @{
366
367  /// getOpcode - Get the kind of this binary expression.
368  Opcode getOpcode() const { return Op; }
369
370  /// getLHS - Get the left-hand side expression of the binary operator.
371  const MCExpr *getLHS() const { return LHS; }
372
373  /// getRHS - Get the right-hand side expression of the binary operator.
374  const MCExpr *getRHS() const { return RHS; }
375
376  /// @}
377
378  static bool classof(const MCExpr *E) {
379    return E->getKind() == MCExpr::Binary;
380  }
381  static bool classof(const MCBinaryExpr *) { return true; }
382};
383
384/// MCTargetExpr - This is an extension point for target-specific MCExpr
385/// subclasses to implement.
386///
387/// NOTE: All subclasses are required to have trivial destructors because
388/// MCExprs are bump pointer allocated and not destructed.
389class MCTargetExpr : public MCExpr {
390  virtual void Anchor();
391protected:
392  MCTargetExpr() : MCExpr(Target) {}
393  virtual ~MCTargetExpr() {}
394public:
395
396  virtual void PrintImpl(raw_ostream &OS) const = 0;
397  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
398                                         const MCAsmLayout *Layout) const = 0;
399
400
401  static bool classof(const MCExpr *E) {
402    return E->getKind() == MCExpr::Target;
403  }
404  static bool classof(const MCTargetExpr *) { return true; }
405};
406
407} // end namespace llvm
408
409#endif
410