MCExpr.h revision f230df9af4012f9510de664b6d62b128e26a5861 
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_PLT,
138    VK_TLSGD,
139    VK_TPOFF,
140    VK_ARM_HI16, // The R_ARM_MOVT_ABS relocation (:upper16: in the asm file)
141    VK_ARM_LO16, // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the asm file)
142    VK_ARM_PLT,  // ARM-style PLT symbol references. i.e., (PLT) instead of @PLT
143    VK_TLVP // Mach-O thread local variable relocation
144  };
145
146private:
147  /// The symbol being referenced.
148  const MCSymbol *Symbol;
149
150  /// The symbol reference modifier.
151  const VariantKind Kind;
152
153  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
154    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
155
156public:
157  /// @name Construction
158  /// @{
159
160  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
161    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
162  }
163
164  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
165                                       MCContext &Ctx);
166  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
167                                       MCContext &Ctx);
168
169  /// @}
170  /// @name Accessors
171  /// @{
172
173  const MCSymbol &getSymbol() const { return *Symbol; }
174
175  VariantKind getKind() const { return Kind; }
176
177  /// @}
178  /// @name Static Utility Functions
179  /// @{
180
181  static StringRef getVariantKindName(VariantKind Kind);
182
183  static VariantKind getVariantKindForName(StringRef Name);
184
185  /// @}
186
187  static bool classof(const MCExpr *E) {
188    return E->getKind() == MCExpr::SymbolRef;
189  }
190  static bool classof(const MCSymbolRefExpr *) { return true; }
191};
192
193/// MCUnaryExpr - Unary assembler expressions.
194class MCUnaryExpr : public MCExpr {
195public:
196  enum Opcode {
197    LNot,  ///< Logical negation.
198    Minus, ///< Unary minus.
199    Not,   ///< Bitwise negation.
200    Plus   ///< Unary plus.
201  };
202
203private:
204  Opcode Op;
205  const MCExpr *Expr;
206
207  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
208    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
209
210public:
211  /// @name Construction
212  /// @{
213
214  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
215                                   MCContext &Ctx);
216  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
217    return Create(LNot, Expr, Ctx);
218  }
219  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
220    return Create(Minus, Expr, Ctx);
221  }
222  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
223    return Create(Not, Expr, Ctx);
224  }
225  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
226    return Create(Plus, Expr, Ctx);
227  }
228
229  /// @}
230  /// @name Accessors
231  /// @{
232
233  /// getOpcode - Get the kind of this unary expression.
234  Opcode getOpcode() const { return Op; }
235
236  /// getSubExpr - Get the child of this unary expression.
237  const MCExpr *getSubExpr() const { return Expr; }
238
239  /// @}
240
241  static bool classof(const MCExpr *E) {
242    return E->getKind() == MCExpr::Unary;
243  }
244  static bool classof(const MCUnaryExpr *) { return true; }
245};
246
247/// MCBinaryExpr - Binary assembler expressions.
248class MCBinaryExpr : public MCExpr {
249public:
250  enum Opcode {
251    Add,  ///< Addition.
252    And,  ///< Bitwise and.
253    Div,  ///< Signed division.
254    EQ,   ///< Equality comparison.
255    GT,   ///< Signed greater than comparison (result is either 0 or some
256          ///< target-specific non-zero value)
257    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
258          ///< some target-specific non-zero value).
259    LAnd, ///< Logical and.
260    LOr,  ///< Logical or.
261    LT,   ///< Signed less than comparison (result is either 0 or
262          ///< some target-specific non-zero value).
263    LTE,  ///< Signed less than or equal comparison (result is either 0 or
264          ///< some target-specific non-zero value).
265    Mod,  ///< Signed remainder.
266    Mul,  ///< Multiplication.
267    NE,   ///< Inequality comparison.
268    Or,   ///< Bitwise or.
269    Shl,  ///< Shift left.
270    Shr,  ///< Shift right (arithmetic or logical, depending on target)
271    Sub,  ///< Subtraction.
272    Xor   ///< Bitwise exclusive or.
273  };
274
275private:
276  Opcode Op;
277  const MCExpr *LHS, *RHS;
278
279  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
280    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
281
282public:
283  /// @name Construction
284  /// @{
285
286  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
287                                    const MCExpr *RHS, MCContext &Ctx);
288  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
289                                       MCContext &Ctx) {
290    return Create(Add, LHS, RHS, Ctx);
291  }
292  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
293                                       MCContext &Ctx) {
294    return Create(And, LHS, RHS, Ctx);
295  }
296  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
297                                       MCContext &Ctx) {
298    return Create(Div, LHS, RHS, Ctx);
299  }
300  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
301                                      MCContext &Ctx) {
302    return Create(EQ, LHS, RHS, Ctx);
303  }
304  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
305                                      MCContext &Ctx) {
306    return Create(GT, LHS, RHS, Ctx);
307  }
308  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
309                                       MCContext &Ctx) {
310    return Create(GTE, LHS, RHS, Ctx);
311  }
312  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
313                                        MCContext &Ctx) {
314    return Create(LAnd, LHS, RHS, Ctx);
315  }
316  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
317                                       MCContext &Ctx) {
318    return Create(LOr, LHS, RHS, Ctx);
319  }
320  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
321                                      MCContext &Ctx) {
322    return Create(LT, LHS, RHS, Ctx);
323  }
324  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
325                                       MCContext &Ctx) {
326    return Create(LTE, LHS, RHS, Ctx);
327  }
328  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
329                                       MCContext &Ctx) {
330    return Create(Mod, LHS, RHS, Ctx);
331  }
332  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
333                                       MCContext &Ctx) {
334    return Create(Mul, LHS, RHS, Ctx);
335  }
336  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
337                                      MCContext &Ctx) {
338    return Create(NE, LHS, RHS, Ctx);
339  }
340  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
341                                      MCContext &Ctx) {
342    return Create(Or, LHS, RHS, Ctx);
343  }
344  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
345                                       MCContext &Ctx) {
346    return Create(Shl, LHS, RHS, Ctx);
347  }
348  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
349                                       MCContext &Ctx) {
350    return Create(Shr, LHS, RHS, Ctx);
351  }
352  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
353                                       MCContext &Ctx) {
354    return Create(Sub, LHS, RHS, Ctx);
355  }
356  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
357                                       MCContext &Ctx) {
358    return Create(Xor, LHS, RHS, Ctx);
359  }
360
361  /// @}
362  /// @name Accessors
363  /// @{
364
365  /// getOpcode - Get the kind of this binary expression.
366  Opcode getOpcode() const { return Op; }
367
368  /// getLHS - Get the left-hand side expression of the binary operator.
369  const MCExpr *getLHS() const { return LHS; }
370
371  /// getRHS - Get the right-hand side expression of the binary operator.
372  const MCExpr *getRHS() const { return RHS; }
373
374  /// @}
375
376  static bool classof(const MCExpr *E) {
377    return E->getKind() == MCExpr::Binary;
378  }
379  static bool classof(const MCBinaryExpr *) { return true; }
380};
381
382/// MCTargetExpr - This is an extension point for target-specific MCExpr
383/// subclasses to implement.
384///
385/// NOTE: All subclasses are required to have trivial destructors because
386/// MCExprs are bump pointer allocated and not destructed.
387class MCTargetExpr : public MCExpr {
388  virtual void Anchor();
389protected:
390  MCTargetExpr() : MCExpr(Target) {}
391  virtual ~MCTargetExpr() {}
392public:
393
394  virtual void PrintImpl(raw_ostream &OS) const = 0;
395  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
396                                         const MCAsmLayout *Layout) const = 0;
397
398
399  static bool classof(const MCExpr *E) {
400    return E->getKind() == MCExpr::Target;
401  }
402  static bool classof(const MCTargetExpr *) { return true; }
403};
404
405} // end namespace llvm
406
407#endif
408