MCExpr.h revision 22373b230a053a154f6c7792c6a33d4f78f5479d 
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/Support/DataTypes.h"
15
16namespace llvm {
17class MCAsmInfo;
18class MCAsmLayout;
19class MCAssembler;
20class MCContext;
21class MCSymbol;
22class MCValue;
23class raw_ostream;
24class StringRef;
25
26/// MCExpr - Base class for the full range of assembler expressions which are
27/// needed for parsing.
28class MCExpr {
29public:
30  enum ExprKind {
31    Binary,    ///< Binary expressions.
32    Constant,  ///< Constant expressions.
33    SymbolRef, ///< References to labels and assigned expressions.
34    Unary,     ///< Unary expressions.
35    Target     ///< Target specific expression.
36  };
37
38private:
39  ExprKind Kind;
40
41  MCExpr(const MCExpr&); // DO NOT IMPLEMENT
42  void operator=(const MCExpr&); // DO NOT IMPLEMENT
43
44  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
45                          const MCAsmLayout *Layout) const;
46protected:
47  explicit MCExpr(ExprKind _Kind) : Kind(_Kind) {}
48
49  bool EvaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
50                                 const MCAsmLayout *Layout,
51                                 bool InSet) const;
52public:
53  /// @name Accessors
54  /// @{
55
56  ExprKind getKind() const { return Kind; }
57
58  /// @}
59  /// @name Utility Methods
60  /// @{
61
62  void print(raw_ostream &OS) const;
63  void dump() const;
64
65  /// @}
66  /// @name Expression Evaluation
67  /// @{
68
69  /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
70  ///
71  /// @param Res - The absolute value, if evaluation succeeds.
72  /// @param Layout - The assembler layout object to use for evaluating symbol
73  /// values. If not given, then only non-symbolic expressions will be
74  /// evaluated.
75  /// @result - True on success.
76  bool EvaluateAsAbsolute(int64_t &Res) const;
77  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const;
78  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
79
80  /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
81  /// value, i.e. an expression of the fixed form (a - b + constant).
82  ///
83  /// @param Res - The relocatable value, if evaluation succeeds.
84  /// @param Layout - The assembler layout object to use for evaluating values.
85  /// @result - True on success.
86  bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout *Layout = 0) const;
87
88  /// @}
89
90  static bool classof(const MCExpr *) { return true; }
91};
92
93inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
94  E.print(OS);
95  return OS;
96}
97
98//// MCConstantExpr - Represent a constant integer expression.
99class MCConstantExpr : public MCExpr {
100  int64_t Value;
101
102  explicit MCConstantExpr(int64_t _Value)
103    : MCExpr(MCExpr::Constant), Value(_Value) {}
104
105public:
106  /// @name Construction
107  /// @{
108
109  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
110
111  /// @}
112  /// @name Accessors
113  /// @{
114
115  int64_t getValue() const { return Value; }
116
117  /// @}
118
119  static bool classof(const MCExpr *E) {
120    return E->getKind() == MCExpr::Constant;
121  }
122  static bool classof(const MCConstantExpr *) { return true; }
123};
124
125/// MCSymbolRefExpr - Represent a reference to a symbol from inside an
126/// expression.
127///
128/// A symbol reference in an expression may be a use of a label, a use of an
129/// assembler variable (defined constant), or constitute an implicit definition
130/// of the symbol as external.
131class MCSymbolRefExpr : public MCExpr {
132public:
133  enum VariantKind {
134    VK_None,
135    VK_Invalid,
136
137    VK_GOT,
138    VK_GOTOFF,
139    VK_GOTPCREL,
140    VK_GOTTPOFF,
141    VK_INDNTPOFF,
142    VK_NTPOFF,
143    VK_GOTNTPOFF,
144    VK_PLT,
145    VK_TLSGD,
146    VK_TLSLD,
147    VK_TLSLDM,
148    VK_TPOFF,
149    VK_DTPOFF,
150    VK_TLVP,      // Mach-O thread local variable relocation
151    VK_ARM_HI16,  // The R_ARM_MOVT_ABS relocation (:upper16: in the .s file)
152    VK_ARM_LO16,  // The R_ARM_MOVW_ABS_NC relocation (:lower16: in the .w file)
153    // FIXME: We'd really like to use the generic Kinds listed above for these.
154    VK_ARM_PLT,   // ARM-style PLT references. i.e., (PLT) instead of @PLT
155    VK_ARM_TLSGD, //   ditto for TLSGD, GOT, GOTOFF, TPOFF and GOTTPOFF
156    VK_ARM_GOT,
157    VK_ARM_GOTOFF,
158    VK_ARM_TPOFF,
159    VK_ARM_GOTTPOFF,
160
161    VK_PPC_TOC,
162    VK_PPC_HA16,  // ha16(symbol)
163    VK_PPC_LO16   // lo16(symbol)
164  };
165
166private:
167  /// The symbol being referenced.
168  const MCSymbol *Symbol;
169
170  /// The symbol reference modifier.
171  const VariantKind Kind;
172
173  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
174    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
175
176public:
177  /// @name Construction
178  /// @{
179
180  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
181    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
182  }
183
184  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
185                                       MCContext &Ctx);
186  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
187                                       MCContext &Ctx);
188
189  /// @}
190  /// @name Accessors
191  /// @{
192
193  const MCSymbol &getSymbol() const { return *Symbol; }
194
195  VariantKind getKind() const { return Kind; }
196
197  /// @}
198  /// @name Static Utility Functions
199  /// @{
200
201  static StringRef getVariantKindName(VariantKind Kind);
202
203  static VariantKind getVariantKindForName(StringRef Name);
204
205  /// @}
206
207  static bool classof(const MCExpr *E) {
208    return E->getKind() == MCExpr::SymbolRef;
209  }
210  static bool classof(const MCSymbolRefExpr *) { return true; }
211};
212
213/// MCUnaryExpr - Unary assembler expressions.
214class MCUnaryExpr : public MCExpr {
215public:
216  enum Opcode {
217    LNot,  ///< Logical negation.
218    Minus, ///< Unary minus.
219    Not,   ///< Bitwise negation.
220    Plus   ///< Unary plus.
221  };
222
223private:
224  Opcode Op;
225  const MCExpr *Expr;
226
227  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
228    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
229
230public:
231  /// @name Construction
232  /// @{
233
234  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
235                                   MCContext &Ctx);
236  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
237    return Create(LNot, Expr, Ctx);
238  }
239  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
240    return Create(Minus, Expr, Ctx);
241  }
242  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
243    return Create(Not, Expr, Ctx);
244  }
245  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
246    return Create(Plus, Expr, Ctx);
247  }
248
249  /// @}
250  /// @name Accessors
251  /// @{
252
253  /// getOpcode - Get the kind of this unary expression.
254  Opcode getOpcode() const { return Op; }
255
256  /// getSubExpr - Get the child of this unary expression.
257  const MCExpr *getSubExpr() const { return Expr; }
258
259  /// @}
260
261  static bool classof(const MCExpr *E) {
262    return E->getKind() == MCExpr::Unary;
263  }
264  static bool classof(const MCUnaryExpr *) { return true; }
265};
266
267/// MCBinaryExpr - Binary assembler expressions.
268class MCBinaryExpr : public MCExpr {
269public:
270  enum Opcode {
271    Add,  ///< Addition.
272    And,  ///< Bitwise and.
273    Div,  ///< Signed division.
274    EQ,   ///< Equality comparison.
275    GT,   ///< Signed greater than comparison (result is either 0 or some
276          ///< target-specific non-zero value)
277    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
278          ///< some target-specific non-zero value).
279    LAnd, ///< Logical and.
280    LOr,  ///< Logical or.
281    LT,   ///< Signed less than comparison (result is either 0 or
282          ///< some target-specific non-zero value).
283    LTE,  ///< Signed less than or equal comparison (result is either 0 or
284          ///< some target-specific non-zero value).
285    Mod,  ///< Signed remainder.
286    Mul,  ///< Multiplication.
287    NE,   ///< Inequality comparison.
288    Or,   ///< Bitwise or.
289    Shl,  ///< Shift left.
290    Shr,  ///< Shift right (arithmetic or logical, depending on target)
291    Sub,  ///< Subtraction.
292    Xor   ///< Bitwise exclusive or.
293  };
294
295private:
296  Opcode Op;
297  const MCExpr *LHS, *RHS;
298
299  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
300    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
301
302public:
303  /// @name Construction
304  /// @{
305
306  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
307                                    const MCExpr *RHS, MCContext &Ctx);
308  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
309                                       MCContext &Ctx) {
310    return Create(Add, LHS, RHS, Ctx);
311  }
312  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
313                                       MCContext &Ctx) {
314    return Create(And, LHS, RHS, Ctx);
315  }
316  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
317                                       MCContext &Ctx) {
318    return Create(Div, LHS, RHS, Ctx);
319  }
320  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
321                                      MCContext &Ctx) {
322    return Create(EQ, LHS, RHS, Ctx);
323  }
324  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
325                                      MCContext &Ctx) {
326    return Create(GT, LHS, RHS, Ctx);
327  }
328  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
329                                       MCContext &Ctx) {
330    return Create(GTE, LHS, RHS, Ctx);
331  }
332  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
333                                        MCContext &Ctx) {
334    return Create(LAnd, LHS, RHS, Ctx);
335  }
336  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
337                                       MCContext &Ctx) {
338    return Create(LOr, LHS, RHS, Ctx);
339  }
340  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
341                                      MCContext &Ctx) {
342    return Create(LT, LHS, RHS, Ctx);
343  }
344  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
345                                       MCContext &Ctx) {
346    return Create(LTE, LHS, RHS, Ctx);
347  }
348  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
349                                       MCContext &Ctx) {
350    return Create(Mod, LHS, RHS, Ctx);
351  }
352  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
353                                       MCContext &Ctx) {
354    return Create(Mul, LHS, RHS, Ctx);
355  }
356  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
357                                      MCContext &Ctx) {
358    return Create(NE, LHS, RHS, Ctx);
359  }
360  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
361                                      MCContext &Ctx) {
362    return Create(Or, LHS, RHS, Ctx);
363  }
364  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
365                                       MCContext &Ctx) {
366    return Create(Shl, LHS, RHS, Ctx);
367  }
368  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
369                                       MCContext &Ctx) {
370    return Create(Shr, LHS, RHS, Ctx);
371  }
372  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
373                                       MCContext &Ctx) {
374    return Create(Sub, LHS, RHS, Ctx);
375  }
376  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
377                                       MCContext &Ctx) {
378    return Create(Xor, LHS, RHS, Ctx);
379  }
380
381  /// @}
382  /// @name Accessors
383  /// @{
384
385  /// getOpcode - Get the kind of this binary expression.
386  Opcode getOpcode() const { return Op; }
387
388  /// getLHS - Get the left-hand side expression of the binary operator.
389  const MCExpr *getLHS() const { return LHS; }
390
391  /// getRHS - Get the right-hand side expression of the binary operator.
392  const MCExpr *getRHS() const { return RHS; }
393
394  /// @}
395
396  static bool classof(const MCExpr *E) {
397    return E->getKind() == MCExpr::Binary;
398  }
399  static bool classof(const MCBinaryExpr *) { return true; }
400};
401
402/// MCTargetExpr - This is an extension point for target-specific MCExpr
403/// subclasses to implement.
404///
405/// NOTE: All subclasses are required to have trivial destructors because
406/// MCExprs are bump pointer allocated and not destructed.
407class MCTargetExpr : public MCExpr {
408  virtual void Anchor();
409protected:
410  MCTargetExpr() : MCExpr(Target) {}
411  virtual ~MCTargetExpr() {}
412public:
413
414  virtual void PrintImpl(raw_ostream &OS) const = 0;
415  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
416                                         const MCAsmLayout *Layout) const = 0;
417
418
419  static bool classof(const MCExpr *E) {
420    return E->getKind() == MCExpr::Target;
421  }
422  static bool classof(const MCTargetExpr *) { return true; }
423};
424
425} // end namespace llvm
426
427#endif
428