MCExpr.h revision 1e61e69d401045c54b15815f15a0fdb3ca56a9b5 
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_TLSLD,
141    VK_TLSLDM,
142    VK_TPOFF,
143    VK_DTPOFF,
144    VK_TLVP,      // Mach-O thread local variable relocation
145    VK_ARM_HI16,  // The R_ARM_MOVT_ABS relocation (:upper16: in the .s file)
146    VK_ARM_LO16,  // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the .w file)
147    // FIXME: We'd really like to use the generic Kinds listed above for these.
148    VK_ARM_PLT,   // ARM-style PLT references. i.e., (PLT) instead of @PLT
149    VK_ARM_TLSGD, //   ditto for TLSGD, GOT, GOTOFF, TPOFF and GOTTPOFF
150    VK_ARM_GOT,
151    VK_ARM_GOTOFF,
152    VK_ARM_TPOFF,
153    VK_ARM_GOTTPOFF,
154
155    VK_PPC_TOC,
156    VK_PPC_HA16,  // ha16(symbol)
157    VK_PPC_LO16   // lo16(symbol)
158  };
159
160private:
161  /// The symbol being referenced.
162  const MCSymbol *Symbol;
163
164  /// The symbol reference modifier.
165  const VariantKind Kind;
166
167  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
168    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
169
170public:
171  /// @name Construction
172  /// @{
173
174  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
175    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
176  }
177
178  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
179                                       MCContext &Ctx);
180  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
181                                       MCContext &Ctx);
182
183  /// @}
184  /// @name Accessors
185  /// @{
186
187  const MCSymbol &getSymbol() const { return *Symbol; }
188
189  VariantKind getKind() const { return Kind; }
190
191  /// @}
192  /// @name Static Utility Functions
193  /// @{
194
195  static StringRef getVariantKindName(VariantKind Kind);
196
197  static VariantKind getVariantKindForName(StringRef Name);
198
199  /// @}
200
201  static bool classof(const MCExpr *E) {
202    return E->getKind() == MCExpr::SymbolRef;
203  }
204  static bool classof(const MCSymbolRefExpr *) { return true; }
205};
206
207/// MCUnaryExpr - Unary assembler expressions.
208class MCUnaryExpr : public MCExpr {
209public:
210  enum Opcode {
211    LNot,  ///< Logical negation.
212    Minus, ///< Unary minus.
213    Not,   ///< Bitwise negation.
214    Plus   ///< Unary plus.
215  };
216
217private:
218  Opcode Op;
219  const MCExpr *Expr;
220
221  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
222    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
223
224public:
225  /// @name Construction
226  /// @{
227
228  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
229                                   MCContext &Ctx);
230  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
231    return Create(LNot, Expr, Ctx);
232  }
233  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
234    return Create(Minus, Expr, Ctx);
235  }
236  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
237    return Create(Not, Expr, Ctx);
238  }
239  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
240    return Create(Plus, Expr, Ctx);
241  }
242
243  /// @}
244  /// @name Accessors
245  /// @{
246
247  /// getOpcode - Get the kind of this unary expression.
248  Opcode getOpcode() const { return Op; }
249
250  /// getSubExpr - Get the child of this unary expression.
251  const MCExpr *getSubExpr() const { return Expr; }
252
253  /// @}
254
255  static bool classof(const MCExpr *E) {
256    return E->getKind() == MCExpr::Unary;
257  }
258  static bool classof(const MCUnaryExpr *) { return true; }
259};
260
261/// MCBinaryExpr - Binary assembler expressions.
262class MCBinaryExpr : public MCExpr {
263public:
264  enum Opcode {
265    Add,  ///< Addition.
266    And,  ///< Bitwise and.
267    Div,  ///< Signed division.
268    EQ,   ///< Equality comparison.
269    GT,   ///< Signed greater than comparison (result is either 0 or some
270          ///< target-specific non-zero value)
271    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
272          ///< some target-specific non-zero value).
273    LAnd, ///< Logical and.
274    LOr,  ///< Logical or.
275    LT,   ///< Signed less than comparison (result is either 0 or
276          ///< some target-specific non-zero value).
277    LTE,  ///< Signed less than or equal comparison (result is either 0 or
278          ///< some target-specific non-zero value).
279    Mod,  ///< Signed remainder.
280    Mul,  ///< Multiplication.
281    NE,   ///< Inequality comparison.
282    Or,   ///< Bitwise or.
283    Shl,  ///< Shift left.
284    Shr,  ///< Shift right (arithmetic or logical, depending on target)
285    Sub,  ///< Subtraction.
286    Xor   ///< Bitwise exclusive or.
287  };
288
289private:
290  Opcode Op;
291  const MCExpr *LHS, *RHS;
292
293  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
294    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
295
296public:
297  /// @name Construction
298  /// @{
299
300  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
301                                    const MCExpr *RHS, MCContext &Ctx);
302  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
303                                       MCContext &Ctx) {
304    return Create(Add, LHS, RHS, Ctx);
305  }
306  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
307                                       MCContext &Ctx) {
308    return Create(And, LHS, RHS, Ctx);
309  }
310  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
311                                       MCContext &Ctx) {
312    return Create(Div, LHS, RHS, Ctx);
313  }
314  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
315                                      MCContext &Ctx) {
316    return Create(EQ, LHS, RHS, Ctx);
317  }
318  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
319                                      MCContext &Ctx) {
320    return Create(GT, LHS, RHS, Ctx);
321  }
322  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
323                                       MCContext &Ctx) {
324    return Create(GTE, LHS, RHS, Ctx);
325  }
326  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
327                                        MCContext &Ctx) {
328    return Create(LAnd, LHS, RHS, Ctx);
329  }
330  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
331                                       MCContext &Ctx) {
332    return Create(LOr, LHS, RHS, Ctx);
333  }
334  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
335                                      MCContext &Ctx) {
336    return Create(LT, LHS, RHS, Ctx);
337  }
338  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
339                                       MCContext &Ctx) {
340    return Create(LTE, LHS, RHS, Ctx);
341  }
342  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
343                                       MCContext &Ctx) {
344    return Create(Mod, LHS, RHS, Ctx);
345  }
346  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
347                                       MCContext &Ctx) {
348    return Create(Mul, LHS, RHS, Ctx);
349  }
350  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
351                                      MCContext &Ctx) {
352    return Create(NE, LHS, RHS, Ctx);
353  }
354  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
355                                      MCContext &Ctx) {
356    return Create(Or, LHS, RHS, Ctx);
357  }
358  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
359                                       MCContext &Ctx) {
360    return Create(Shl, LHS, RHS, Ctx);
361  }
362  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
363                                       MCContext &Ctx) {
364    return Create(Shr, LHS, RHS, Ctx);
365  }
366  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
367                                       MCContext &Ctx) {
368    return Create(Sub, LHS, RHS, Ctx);
369  }
370  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
371                                       MCContext &Ctx) {
372    return Create(Xor, LHS, RHS, Ctx);
373  }
374
375  /// @}
376  /// @name Accessors
377  /// @{
378
379  /// getOpcode - Get the kind of this binary expression.
380  Opcode getOpcode() const { return Op; }
381
382  /// getLHS - Get the left-hand side expression of the binary operator.
383  const MCExpr *getLHS() const { return LHS; }
384
385  /// getRHS - Get the right-hand side expression of the binary operator.
386  const MCExpr *getRHS() const { return RHS; }
387
388  /// @}
389
390  static bool classof(const MCExpr *E) {
391    return E->getKind() == MCExpr::Binary;
392  }
393  static bool classof(const MCBinaryExpr *) { return true; }
394};
395
396/// MCTargetExpr - This is an extension point for target-specific MCExpr
397/// subclasses to implement.
398///
399/// NOTE: All subclasses are required to have trivial destructors because
400/// MCExprs are bump pointer allocated and not destructed.
401class MCTargetExpr : public MCExpr {
402  virtual void Anchor();
403protected:
404  MCTargetExpr() : MCExpr(Target) {}
405  virtual ~MCTargetExpr() {}
406public:
407
408  virtual void PrintImpl(raw_ostream &OS) const = 0;
409  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
410                                         const MCAsmLayout *Layout) const = 0;
411
412
413  static bool classof(const MCExpr *E) {
414    return E->getKind() == MCExpr::Target;
415  }
416  static bool classof(const MCTargetExpr *) { return true; }
417};
418
419} // end namespace llvm
420
421#endif
422