MCExpr.h revision 2c4d5125c708bb35140fc2a40b02beb1add101db 
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_ARM_HI16,  // The R_ARM_MOVT_ABS relocation (:upper16: in the .s file)
145    VK_ARM_LO16,  // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the .w file)
146    // FIXME: We'd really like to use the generic Kinds listed above for these.
147    VK_ARM_PLT,   // ARM-style PLT references. i.e., (PLT) instead of @PLT
148    VK_ARM_TLSGD, //   ditto for TLSGD, GOT, GOTOFF, TPOFF and GOTTPOFF
149    VK_ARM_GOT,
150    VK_ARM_GOTOFF,
151    VK_ARM_TPOFF,
152    VK_ARM_GOTTPOFF,
153    VK_TLVP // Mach-O thread local variable relocation
154  };
155
156private:
157  /// The symbol being referenced.
158  const MCSymbol *Symbol;
159
160  /// The symbol reference modifier.
161  const VariantKind Kind;
162
163  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
164    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
165
166public:
167  /// @name Construction
168  /// @{
169
170  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
171    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
172  }
173
174  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
175                                       MCContext &Ctx);
176  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
177                                       MCContext &Ctx);
178
179  /// @}
180  /// @name Accessors
181  /// @{
182
183  const MCSymbol &getSymbol() const { return *Symbol; }
184
185  VariantKind getKind() const { return Kind; }
186
187  /// @}
188  /// @name Static Utility Functions
189  /// @{
190
191  static StringRef getVariantKindName(VariantKind Kind);
192
193  static VariantKind getVariantKindForName(StringRef Name);
194
195  /// @}
196
197  static bool classof(const MCExpr *E) {
198    return E->getKind() == MCExpr::SymbolRef;
199  }
200  static bool classof(const MCSymbolRefExpr *) { return true; }
201};
202
203/// MCUnaryExpr - Unary assembler expressions.
204class MCUnaryExpr : public MCExpr {
205public:
206  enum Opcode {
207    LNot,  ///< Logical negation.
208    Minus, ///< Unary minus.
209    Not,   ///< Bitwise negation.
210    Plus   ///< Unary plus.
211  };
212
213private:
214  Opcode Op;
215  const MCExpr *Expr;
216
217  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
218    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
219
220public:
221  /// @name Construction
222  /// @{
223
224  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
225                                   MCContext &Ctx);
226  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
227    return Create(LNot, Expr, Ctx);
228  }
229  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
230    return Create(Minus, Expr, Ctx);
231  }
232  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
233    return Create(Not, Expr, Ctx);
234  }
235  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
236    return Create(Plus, Expr, Ctx);
237  }
238
239  /// @}
240  /// @name Accessors
241  /// @{
242
243  /// getOpcode - Get the kind of this unary expression.
244  Opcode getOpcode() const { return Op; }
245
246  /// getSubExpr - Get the child of this unary expression.
247  const MCExpr *getSubExpr() const { return Expr; }
248
249  /// @}
250
251  static bool classof(const MCExpr *E) {
252    return E->getKind() == MCExpr::Unary;
253  }
254  static bool classof(const MCUnaryExpr *) { return true; }
255};
256
257/// MCBinaryExpr - Binary assembler expressions.
258class MCBinaryExpr : public MCExpr {
259public:
260  enum Opcode {
261    Add,  ///< Addition.
262    And,  ///< Bitwise and.
263    Div,  ///< Signed division.
264    EQ,   ///< Equality comparison.
265    GT,   ///< Signed greater than comparison (result is either 0 or some
266          ///< target-specific non-zero value)
267    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
268          ///< some target-specific non-zero value).
269    LAnd, ///< Logical and.
270    LOr,  ///< Logical or.
271    LT,   ///< Signed less than comparison (result is either 0 or
272          ///< some target-specific non-zero value).
273    LTE,  ///< Signed less than or equal comparison (result is either 0 or
274          ///< some target-specific non-zero value).
275    Mod,  ///< Signed remainder.
276    Mul,  ///< Multiplication.
277    NE,   ///< Inequality comparison.
278    Or,   ///< Bitwise or.
279    Shl,  ///< Shift left.
280    Shr,  ///< Shift right (arithmetic or logical, depending on target)
281    Sub,  ///< Subtraction.
282    Xor   ///< Bitwise exclusive or.
283  };
284
285private:
286  Opcode Op;
287  const MCExpr *LHS, *RHS;
288
289  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
290    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
291
292public:
293  /// @name Construction
294  /// @{
295
296  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
297                                    const MCExpr *RHS, MCContext &Ctx);
298  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
299                                       MCContext &Ctx) {
300    return Create(Add, LHS, RHS, Ctx);
301  }
302  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
303                                       MCContext &Ctx) {
304    return Create(And, LHS, RHS, Ctx);
305  }
306  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
307                                       MCContext &Ctx) {
308    return Create(Div, LHS, RHS, Ctx);
309  }
310  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
311                                      MCContext &Ctx) {
312    return Create(EQ, LHS, RHS, Ctx);
313  }
314  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
315                                      MCContext &Ctx) {
316    return Create(GT, LHS, RHS, Ctx);
317  }
318  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
319                                       MCContext &Ctx) {
320    return Create(GTE, LHS, RHS, Ctx);
321  }
322  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
323                                        MCContext &Ctx) {
324    return Create(LAnd, LHS, RHS, Ctx);
325  }
326  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
327                                       MCContext &Ctx) {
328    return Create(LOr, LHS, RHS, Ctx);
329  }
330  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
331                                      MCContext &Ctx) {
332    return Create(LT, LHS, RHS, Ctx);
333  }
334  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
335                                       MCContext &Ctx) {
336    return Create(LTE, LHS, RHS, Ctx);
337  }
338  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
339                                       MCContext &Ctx) {
340    return Create(Mod, LHS, RHS, Ctx);
341  }
342  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
343                                       MCContext &Ctx) {
344    return Create(Mul, LHS, RHS, Ctx);
345  }
346  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
347                                      MCContext &Ctx) {
348    return Create(NE, LHS, RHS, Ctx);
349  }
350  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
351                                      MCContext &Ctx) {
352    return Create(Or, LHS, RHS, Ctx);
353  }
354  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
355                                       MCContext &Ctx) {
356    return Create(Shl, LHS, RHS, Ctx);
357  }
358  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
359                                       MCContext &Ctx) {
360    return Create(Shr, LHS, RHS, Ctx);
361  }
362  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
363                                       MCContext &Ctx) {
364    return Create(Sub, LHS, RHS, Ctx);
365  }
366  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
367                                       MCContext &Ctx) {
368    return Create(Xor, LHS, RHS, Ctx);
369  }
370
371  /// @}
372  /// @name Accessors
373  /// @{
374
375  /// getOpcode - Get the kind of this binary expression.
376  Opcode getOpcode() const { return Op; }
377
378  /// getLHS - Get the left-hand side expression of the binary operator.
379  const MCExpr *getLHS() const { return LHS; }
380
381  /// getRHS - Get the right-hand side expression of the binary operator.
382  const MCExpr *getRHS() const { return RHS; }
383
384  /// @}
385
386  static bool classof(const MCExpr *E) {
387    return E->getKind() == MCExpr::Binary;
388  }
389  static bool classof(const MCBinaryExpr *) { return true; }
390};
391
392/// MCTargetExpr - This is an extension point for target-specific MCExpr
393/// subclasses to implement.
394///
395/// NOTE: All subclasses are required to have trivial destructors because
396/// MCExprs are bump pointer allocated and not destructed.
397class MCTargetExpr : public MCExpr {
398  virtual void Anchor();
399protected:
400  MCTargetExpr() : MCExpr(Target) {}
401  virtual ~MCTargetExpr() {}
402public:
403
404  virtual void PrintImpl(raw_ostream &OS) const = 0;
405  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
406                                         const MCAsmLayout *Layout) const = 0;
407
408
409  static bool classof(const MCExpr *E) {
410    return E->getKind() == MCExpr::Target;
411  }
412  static bool classof(const MCTargetExpr *) { return true; }
413};
414
415} // end namespace llvm
416
417#endif
418