MCExpr.h revision 0eab5c4d85b4c4bb161bcdd959aa58a6f54415cc 
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/ADT/DenseMap.h"
14#include "llvm/Support/Casting.h"
15#include "llvm/Support/DataTypes.h"
16
17namespace llvm {
18class MCAsmInfo;
19class MCAsmLayout;
20class MCAssembler;
21class MCContext;
22class MCSection;
23class MCSectionData;
24class MCSymbol;
25class MCValue;
26class raw_ostream;
27class StringRef;
28typedef DenseMap<const MCSectionData*, uint64_t> SectionAddrMap;
29
30/// MCExpr - Base class for the full range of assembler expressions which are
31/// needed for parsing.
32class MCExpr {
33public:
34  enum ExprKind {
35    Binary,    ///< Binary expressions.
36    Constant,  ///< Constant expressions.
37    SymbolRef, ///< References to labels and assigned expressions.
38    Unary,     ///< Unary expressions.
39    Target     ///< Target specific expression.
40  };
41
42private:
43  ExprKind Kind;
44
45  MCExpr(const MCExpr&); // DO NOT IMPLEMENT
46  void operator=(const MCExpr&); // DO NOT IMPLEMENT
47
48  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
49                          const MCAsmLayout *Layout,
50                          const SectionAddrMap *Addrs) const;
51protected:
52  explicit MCExpr(ExprKind _Kind) : Kind(_Kind) {}
53
54  bool EvaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
55                                 const MCAsmLayout *Layout,
56                                 const SectionAddrMap *Addrs,
57                                 bool InSet) const;
58public:
59  /// @name Accessors
60  /// @{
61
62  ExprKind getKind() const { return Kind; }
63
64  /// @}
65  /// @name Utility Methods
66  /// @{
67
68  void print(raw_ostream &OS) const;
69  void dump() const;
70
71  /// @}
72  /// @name Expression Evaluation
73  /// @{
74
75  /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
76  ///
77  /// @param Res - The absolute value, if evaluation succeeds.
78  /// @param Layout - The assembler layout object to use for evaluating symbol
79  /// values. If not given, then only non-symbolic expressions will be
80  /// evaluated.
81  /// @result - True on success.
82  bool EvaluateAsAbsolute(int64_t &Res) const;
83  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const;
84  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
85  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout,
86                          const SectionAddrMap &Addrs) const;
87
88  /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
89  /// value, i.e. an expression of the fixed form (a - b + constant).
90  ///
91  /// @param Res - The relocatable value, if evaluation succeeds.
92  /// @param Layout - The assembler layout object to use for evaluating values.
93  /// @result - True on success.
94  bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout &Layout) const;
95
96  /// FindAssociatedSection - Find the "associated section" for this expression,
97  /// which is currently defined as the absolute section for constants, or
98  /// otherwise the section associated with the first defined symbol in the
99  /// expression.
100  const MCSection *FindAssociatedSection() const;
101
102  /// @}
103
104  static bool classof(const MCExpr *) { return true; }
105};
106
107inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
108  E.print(OS);
109  return OS;
110}
111
112//// MCConstantExpr - Represent a constant integer expression.
113class MCConstantExpr : public MCExpr {
114  int64_t Value;
115
116  explicit MCConstantExpr(int64_t _Value)
117    : MCExpr(MCExpr::Constant), Value(_Value) {}
118
119public:
120  /// @name Construction
121  /// @{
122
123  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
124
125  /// @}
126  /// @name Accessors
127  /// @{
128
129  int64_t getValue() const { return Value; }
130
131  /// @}
132
133  static bool classof(const MCExpr *E) {
134    return E->getKind() == MCExpr::Constant;
135  }
136  static bool classof(const MCConstantExpr *) { return true; }
137};
138
139/// MCSymbolRefExpr - Represent a reference to a symbol from inside an
140/// expression.
141///
142/// A symbol reference in an expression may be a use of a label, a use of an
143/// assembler variable (defined constant), or constitute an implicit definition
144/// of the symbol as external.
145class MCSymbolRefExpr : public MCExpr {
146public:
147  enum VariantKind {
148    VK_None,
149    VK_Invalid,
150
151    VK_GOT,
152    VK_GOTOFF,
153    VK_GOTPCREL,
154    VK_GOTTPOFF,
155    VK_INDNTPOFF,
156    VK_NTPOFF,
157    VK_GOTNTPOFF,
158    VK_PLT,
159    VK_TLSGD,
160    VK_TLSLD,
161    VK_TLSLDM,
162    VK_TPOFF,
163    VK_DTPOFF,
164    VK_TLVP,      // Mach-O thread local variable relocation
165    // FIXME: We'd really like to use the generic Kinds listed above for these.
166    VK_ARM_PLT,   // ARM-style PLT references. i.e., (PLT) instead of @PLT
167    VK_ARM_TLSGD, //   ditto for TLSGD, GOT, GOTOFF, TPOFF and GOTTPOFF
168    VK_ARM_GOT,
169    VK_ARM_GOTOFF,
170    VK_ARM_TPOFF,
171    VK_ARM_GOTTPOFF,
172
173    VK_PPC_TOC,
174    VK_PPC_HA16,  // ha16(symbol)
175    VK_PPC_LO16   // lo16(symbol)
176  };
177
178private:
179  /// The symbol being referenced.
180  const MCSymbol *Symbol;
181
182  /// The symbol reference modifier.
183  const VariantKind Kind;
184
185  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
186    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
187
188public:
189  /// @name Construction
190  /// @{
191
192  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
193    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
194  }
195
196  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
197                                       MCContext &Ctx);
198  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
199                                       MCContext &Ctx);
200
201  /// @}
202  /// @name Accessors
203  /// @{
204
205  const MCSymbol &getSymbol() const { return *Symbol; }
206
207  VariantKind getKind() const { return Kind; }
208
209  /// @}
210  /// @name Static Utility Functions
211  /// @{
212
213  static StringRef getVariantKindName(VariantKind Kind);
214
215  static VariantKind getVariantKindForName(StringRef Name);
216
217  /// @}
218
219  static bool classof(const MCExpr *E) {
220    return E->getKind() == MCExpr::SymbolRef;
221  }
222  static bool classof(const MCSymbolRefExpr *) { return true; }
223};
224
225/// MCUnaryExpr - Unary assembler expressions.
226class MCUnaryExpr : public MCExpr {
227public:
228  enum Opcode {
229    LNot,  ///< Logical negation.
230    Minus, ///< Unary minus.
231    Not,   ///< Bitwise negation.
232    Plus   ///< Unary plus.
233  };
234
235private:
236  Opcode Op;
237  const MCExpr *Expr;
238
239  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
240    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
241
242public:
243  /// @name Construction
244  /// @{
245
246  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
247                                   MCContext &Ctx);
248  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
249    return Create(LNot, Expr, Ctx);
250  }
251  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
252    return Create(Minus, Expr, Ctx);
253  }
254  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
255    return Create(Not, Expr, Ctx);
256  }
257  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
258    return Create(Plus, Expr, Ctx);
259  }
260
261  /// @}
262  /// @name Accessors
263  /// @{
264
265  /// getOpcode - Get the kind of this unary expression.
266  Opcode getOpcode() const { return Op; }
267
268  /// getSubExpr - Get the child of this unary expression.
269  const MCExpr *getSubExpr() const { return Expr; }
270
271  /// @}
272
273  static bool classof(const MCExpr *E) {
274    return E->getKind() == MCExpr::Unary;
275  }
276  static bool classof(const MCUnaryExpr *) { return true; }
277};
278
279/// MCBinaryExpr - Binary assembler expressions.
280class MCBinaryExpr : public MCExpr {
281public:
282  enum Opcode {
283    Add,  ///< Addition.
284    And,  ///< Bitwise and.
285    Div,  ///< Signed division.
286    EQ,   ///< Equality comparison.
287    GT,   ///< Signed greater than comparison (result is either 0 or some
288          ///< target-specific non-zero value)
289    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
290          ///< some target-specific non-zero value).
291    LAnd, ///< Logical and.
292    LOr,  ///< Logical or.
293    LT,   ///< Signed less than comparison (result is either 0 or
294          ///< some target-specific non-zero value).
295    LTE,  ///< Signed less than or equal comparison (result is either 0 or
296          ///< some target-specific non-zero value).
297    Mod,  ///< Signed remainder.
298    Mul,  ///< Multiplication.
299    NE,   ///< Inequality comparison.
300    Or,   ///< Bitwise or.
301    Shl,  ///< Shift left.
302    Shr,  ///< Shift right (arithmetic or logical, depending on target)
303    Sub,  ///< Subtraction.
304    Xor   ///< Bitwise exclusive or.
305  };
306
307private:
308  Opcode Op;
309  const MCExpr *LHS, *RHS;
310
311  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
312    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
313
314public:
315  /// @name Construction
316  /// @{
317
318  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
319                                    const MCExpr *RHS, MCContext &Ctx);
320  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
321                                       MCContext &Ctx) {
322    return Create(Add, LHS, RHS, Ctx);
323  }
324  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
325                                       MCContext &Ctx) {
326    return Create(And, LHS, RHS, Ctx);
327  }
328  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
329                                       MCContext &Ctx) {
330    return Create(Div, LHS, RHS, Ctx);
331  }
332  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
333                                      MCContext &Ctx) {
334    return Create(EQ, LHS, RHS, Ctx);
335  }
336  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
337                                      MCContext &Ctx) {
338    return Create(GT, LHS, RHS, Ctx);
339  }
340  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
341                                       MCContext &Ctx) {
342    return Create(GTE, LHS, RHS, Ctx);
343  }
344  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
345                                        MCContext &Ctx) {
346    return Create(LAnd, LHS, RHS, Ctx);
347  }
348  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
349                                       MCContext &Ctx) {
350    return Create(LOr, LHS, RHS, Ctx);
351  }
352  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
353                                      MCContext &Ctx) {
354    return Create(LT, LHS, RHS, Ctx);
355  }
356  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
357                                       MCContext &Ctx) {
358    return Create(LTE, LHS, RHS, Ctx);
359  }
360  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
361                                       MCContext &Ctx) {
362    return Create(Mod, LHS, RHS, Ctx);
363  }
364  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
365                                       MCContext &Ctx) {
366    return Create(Mul, LHS, RHS, Ctx);
367  }
368  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
369                                      MCContext &Ctx) {
370    return Create(NE, LHS, RHS, Ctx);
371  }
372  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
373                                      MCContext &Ctx) {
374    return Create(Or, LHS, RHS, Ctx);
375  }
376  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
377                                       MCContext &Ctx) {
378    return Create(Shl, LHS, RHS, Ctx);
379  }
380  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
381                                       MCContext &Ctx) {
382    return Create(Shr, LHS, RHS, Ctx);
383  }
384  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
385                                       MCContext &Ctx) {
386    return Create(Sub, LHS, RHS, Ctx);
387  }
388  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
389                                       MCContext &Ctx) {
390    return Create(Xor, LHS, RHS, Ctx);
391  }
392
393  /// @}
394  /// @name Accessors
395  /// @{
396
397  /// getOpcode - Get the kind of this binary expression.
398  Opcode getOpcode() const { return Op; }
399
400  /// getLHS - Get the left-hand side expression of the binary operator.
401  const MCExpr *getLHS() const { return LHS; }
402
403  /// getRHS - Get the right-hand side expression of the binary operator.
404  const MCExpr *getRHS() const { return RHS; }
405
406  /// @}
407
408  static bool classof(const MCExpr *E) {
409    return E->getKind() == MCExpr::Binary;
410  }
411  static bool classof(const MCBinaryExpr *) { return true; }
412};
413
414/// MCTargetExpr - This is an extension point for target-specific MCExpr
415/// subclasses to implement.
416///
417/// NOTE: All subclasses are required to have trivial destructors because
418/// MCExprs are bump pointer allocated and not destructed.
419class MCTargetExpr : public MCExpr {
420  virtual void Anchor();
421protected:
422  MCTargetExpr() : MCExpr(Target) {}
423  virtual ~MCTargetExpr() {}
424public:
425
426  virtual void PrintImpl(raw_ostream &OS) const = 0;
427  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
428                                         const MCAsmLayout *Layout) const = 0;
429  virtual void AddValueSymbols(MCAssembler *) const = 0;
430  virtual const MCSection *FindAssociatedSection() const = 0;
431
432  static bool classof(const MCExpr *E) {
433    return E->getKind() == MCExpr::Target;
434  }
435  static bool classof(const MCTargetExpr *) { return true; }
436};
437
438} // end namespace llvm
439
440#endif
441