MCExpr.h revision 0cf15d61b7e3bf53f5a99f58ada37b93bc039559 
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_DTPOFF,
143    VK_ARM_HI16, // The R_ARM_MOVT_ABS relocation (:upper16: in the asm file)
144    VK_ARM_LO16, // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the asm file)
145    VK_ARM_PLT,  // ARM-style PLT symbol references. i.e., (PLT) instead of @PLT
146    VK_TLVP // Mach-O thread local variable relocation
147  };
148
149private:
150  /// The symbol being referenced.
151  const MCSymbol *Symbol;
152
153  /// The symbol reference modifier.
154  const VariantKind Kind;
155
156  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
157    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
158
159public:
160  /// @name Construction
161  /// @{
162
163  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
164    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
165  }
166
167  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
168                                       MCContext &Ctx);
169  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
170                                       MCContext &Ctx);
171
172  /// @}
173  /// @name Accessors
174  /// @{
175
176  const MCSymbol &getSymbol() const { return *Symbol; }
177
178  VariantKind getKind() const { return Kind; }
179
180  /// @}
181  /// @name Static Utility Functions
182  /// @{
183
184  static StringRef getVariantKindName(VariantKind Kind);
185
186  static VariantKind getVariantKindForName(StringRef Name);
187
188  /// @}
189
190  static bool classof(const MCExpr *E) {
191    return E->getKind() == MCExpr::SymbolRef;
192  }
193  static bool classof(const MCSymbolRefExpr *) { return true; }
194};
195
196/// MCUnaryExpr - Unary assembler expressions.
197class MCUnaryExpr : public MCExpr {
198public:
199  enum Opcode {
200    LNot,  ///< Logical negation.
201    Minus, ///< Unary minus.
202    Not,   ///< Bitwise negation.
203    Plus   ///< Unary plus.
204  };
205
206private:
207  Opcode Op;
208  const MCExpr *Expr;
209
210  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
211    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
212
213public:
214  /// @name Construction
215  /// @{
216
217  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
218                                   MCContext &Ctx);
219  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
220    return Create(LNot, Expr, Ctx);
221  }
222  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
223    return Create(Minus, Expr, Ctx);
224  }
225  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
226    return Create(Not, Expr, Ctx);
227  }
228  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
229    return Create(Plus, Expr, Ctx);
230  }
231
232  /// @}
233  /// @name Accessors
234  /// @{
235
236  /// getOpcode - Get the kind of this unary expression.
237  Opcode getOpcode() const { return Op; }
238
239  /// getSubExpr - Get the child of this unary expression.
240  const MCExpr *getSubExpr() const { return Expr; }
241
242  /// @}
243
244  static bool classof(const MCExpr *E) {
245    return E->getKind() == MCExpr::Unary;
246  }
247  static bool classof(const MCUnaryExpr *) { return true; }
248};
249
250/// MCBinaryExpr - Binary assembler expressions.
251class MCBinaryExpr : public MCExpr {
252public:
253  enum Opcode {
254    Add,  ///< Addition.
255    And,  ///< Bitwise and.
256    Div,  ///< Signed division.
257    EQ,   ///< Equality comparison.
258    GT,   ///< Signed greater than comparison (result is either 0 or some
259          ///< target-specific non-zero value)
260    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
261          ///< some target-specific non-zero value).
262    LAnd, ///< Logical and.
263    LOr,  ///< Logical or.
264    LT,   ///< Signed less than comparison (result is either 0 or
265          ///< some target-specific non-zero value).
266    LTE,  ///< Signed less than or equal comparison (result is either 0 or
267          ///< some target-specific non-zero value).
268    Mod,  ///< Signed remainder.
269    Mul,  ///< Multiplication.
270    NE,   ///< Inequality comparison.
271    Or,   ///< Bitwise or.
272    Shl,  ///< Shift left.
273    Shr,  ///< Shift right (arithmetic or logical, depending on target)
274    Sub,  ///< Subtraction.
275    Xor   ///< Bitwise exclusive or.
276  };
277
278private:
279  Opcode Op;
280  const MCExpr *LHS, *RHS;
281
282  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
283    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
284
285public:
286  /// @name Construction
287  /// @{
288
289  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
290                                    const MCExpr *RHS, MCContext &Ctx);
291  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
292                                       MCContext &Ctx) {
293    return Create(Add, LHS, RHS, Ctx);
294  }
295  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
296                                       MCContext &Ctx) {
297    return Create(And, LHS, RHS, Ctx);
298  }
299  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
300                                       MCContext &Ctx) {
301    return Create(Div, LHS, RHS, Ctx);
302  }
303  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
304                                      MCContext &Ctx) {
305    return Create(EQ, LHS, RHS, Ctx);
306  }
307  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
308                                      MCContext &Ctx) {
309    return Create(GT, LHS, RHS, Ctx);
310  }
311  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
312                                       MCContext &Ctx) {
313    return Create(GTE, LHS, RHS, Ctx);
314  }
315  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
316                                        MCContext &Ctx) {
317    return Create(LAnd, LHS, RHS, Ctx);
318  }
319  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
320                                       MCContext &Ctx) {
321    return Create(LOr, LHS, RHS, Ctx);
322  }
323  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
324                                      MCContext &Ctx) {
325    return Create(LT, LHS, RHS, Ctx);
326  }
327  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
328                                       MCContext &Ctx) {
329    return Create(LTE, LHS, RHS, Ctx);
330  }
331  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
332                                       MCContext &Ctx) {
333    return Create(Mod, LHS, RHS, Ctx);
334  }
335  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
336                                       MCContext &Ctx) {
337    return Create(Mul, LHS, RHS, Ctx);
338  }
339  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
340                                      MCContext &Ctx) {
341    return Create(NE, LHS, RHS, Ctx);
342  }
343  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
344                                      MCContext &Ctx) {
345    return Create(Or, LHS, RHS, Ctx);
346  }
347  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
348                                       MCContext &Ctx) {
349    return Create(Shl, LHS, RHS, Ctx);
350  }
351  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
352                                       MCContext &Ctx) {
353    return Create(Shr, LHS, RHS, Ctx);
354  }
355  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
356                                       MCContext &Ctx) {
357    return Create(Sub, LHS, RHS, Ctx);
358  }
359  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
360                                       MCContext &Ctx) {
361    return Create(Xor, LHS, RHS, Ctx);
362  }
363
364  /// @}
365  /// @name Accessors
366  /// @{
367
368  /// getOpcode - Get the kind of this binary expression.
369  Opcode getOpcode() const { return Op; }
370
371  /// getLHS - Get the left-hand side expression of the binary operator.
372  const MCExpr *getLHS() const { return LHS; }
373
374  /// getRHS - Get the right-hand side expression of the binary operator.
375  const MCExpr *getRHS() const { return RHS; }
376
377  /// @}
378
379  static bool classof(const MCExpr *E) {
380    return E->getKind() == MCExpr::Binary;
381  }
382  static bool classof(const MCBinaryExpr *) { return true; }
383};
384
385/// MCTargetExpr - This is an extension point for target-specific MCExpr
386/// subclasses to implement.
387///
388/// NOTE: All subclasses are required to have trivial destructors because
389/// MCExprs are bump pointer allocated and not destructed.
390class MCTargetExpr : public MCExpr {
391  virtual void Anchor();
392protected:
393  MCTargetExpr() : MCExpr(Target) {}
394  virtual ~MCTargetExpr() {}
395public:
396
397  virtual void PrintImpl(raw_ostream &OS) const = 0;
398  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
399                                         const MCAsmLayout *Layout) const = 0;
400
401
402  static bool classof(const MCExpr *E) {
403    return E->getKind() == MCExpr::Target;
404  }
405  static bool classof(const MCTargetExpr *) { return true; }
406};
407
408} // end namespace llvm
409
410#endif
411