MCExpr.h revision e3d3572e282733bd7aa5ac14115ed0804174e426 
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_DARWIN_HA16,  // ha16(symbol)
175    VK_PPC_DARWIN_LO16,  // lo16(symbol)
176    VK_PPC_GAS_HA16,     // symbol@ha
177    VK_PPC_GAS_LO16,      // symbol@l
178
179    VK_Mips_None,
180    VK_Mips_GPREL,
181    VK_Mips_GOT_CALL,
182    VK_Mips_GOT16,
183    VK_Mips_GOT,
184    VK_Mips_ABS_HI,
185    VK_Mips_ABS_LO,
186    VK_Mips_TLSGD,
187    VK_Mips_GOTTPREL,
188    VK_Mips_TPREL_HI,
189    VK_Mips_TPREL_LO,
190    VK_Mips_GPOFF_HI,
191    VK_Mips_GPOFF_LO,
192    VK_Mips_GOT_DISP,
193    VK_Mips_GOT_PAGE,
194    VK_Mips_GOT_OFST
195  };
196
197private:
198  /// The symbol being referenced.
199  const MCSymbol *Symbol;
200
201  /// The symbol reference modifier.
202  const VariantKind Kind;
203
204  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
205    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
206
207public:
208  /// @name Construction
209  /// @{
210
211  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
212    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
213  }
214
215  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
216                                       MCContext &Ctx);
217  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
218                                       MCContext &Ctx);
219
220  /// @}
221  /// @name Accessors
222  /// @{
223
224  const MCSymbol &getSymbol() const { return *Symbol; }
225
226  VariantKind getKind() const { return Kind; }
227
228  /// @}
229  /// @name Static Utility Functions
230  /// @{
231
232  static StringRef getVariantKindName(VariantKind Kind);
233
234  static VariantKind getVariantKindForName(StringRef Name);
235
236  /// @}
237
238  static bool classof(const MCExpr *E) {
239    return E->getKind() == MCExpr::SymbolRef;
240  }
241  static bool classof(const MCSymbolRefExpr *) { return true; }
242};
243
244/// MCUnaryExpr - Unary assembler expressions.
245class MCUnaryExpr : public MCExpr {
246public:
247  enum Opcode {
248    LNot,  ///< Logical negation.
249    Minus, ///< Unary minus.
250    Not,   ///< Bitwise negation.
251    Plus   ///< Unary plus.
252  };
253
254private:
255  Opcode Op;
256  const MCExpr *Expr;
257
258  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
259    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
260
261public:
262  /// @name Construction
263  /// @{
264
265  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
266                                   MCContext &Ctx);
267  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
268    return Create(LNot, Expr, Ctx);
269  }
270  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
271    return Create(Minus, Expr, Ctx);
272  }
273  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
274    return Create(Not, Expr, Ctx);
275  }
276  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
277    return Create(Plus, Expr, Ctx);
278  }
279
280  /// @}
281  /// @name Accessors
282  /// @{
283
284  /// getOpcode - Get the kind of this unary expression.
285  Opcode getOpcode() const { return Op; }
286
287  /// getSubExpr - Get the child of this unary expression.
288  const MCExpr *getSubExpr() const { return Expr; }
289
290  /// @}
291
292  static bool classof(const MCExpr *E) {
293    return E->getKind() == MCExpr::Unary;
294  }
295  static bool classof(const MCUnaryExpr *) { return true; }
296};
297
298/// MCBinaryExpr - Binary assembler expressions.
299class MCBinaryExpr : public MCExpr {
300public:
301  enum Opcode {
302    Add,  ///< Addition.
303    And,  ///< Bitwise and.
304    Div,  ///< Signed division.
305    EQ,   ///< Equality comparison.
306    GT,   ///< Signed greater than comparison (result is either 0 or some
307          ///< target-specific non-zero value)
308    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
309          ///< some target-specific non-zero value).
310    LAnd, ///< Logical and.
311    LOr,  ///< Logical or.
312    LT,   ///< Signed less than comparison (result is either 0 or
313          ///< some target-specific non-zero value).
314    LTE,  ///< Signed less than or equal comparison (result is either 0 or
315          ///< some target-specific non-zero value).
316    Mod,  ///< Signed remainder.
317    Mul,  ///< Multiplication.
318    NE,   ///< Inequality comparison.
319    Or,   ///< Bitwise or.
320    Shl,  ///< Shift left.
321    Shr,  ///< Shift right (arithmetic or logical, depending on target)
322    Sub,  ///< Subtraction.
323    Xor   ///< Bitwise exclusive or.
324  };
325
326private:
327  Opcode Op;
328  const MCExpr *LHS, *RHS;
329
330  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
331    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
332
333public:
334  /// @name Construction
335  /// @{
336
337  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
338                                    const MCExpr *RHS, MCContext &Ctx);
339  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
340                                       MCContext &Ctx) {
341    return Create(Add, LHS, RHS, Ctx);
342  }
343  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
344                                       MCContext &Ctx) {
345    return Create(And, LHS, RHS, Ctx);
346  }
347  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
348                                       MCContext &Ctx) {
349    return Create(Div, LHS, RHS, Ctx);
350  }
351  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
352                                      MCContext &Ctx) {
353    return Create(EQ, LHS, RHS, Ctx);
354  }
355  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
356                                      MCContext &Ctx) {
357    return Create(GT, LHS, RHS, Ctx);
358  }
359  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
360                                       MCContext &Ctx) {
361    return Create(GTE, LHS, RHS, Ctx);
362  }
363  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
364                                        MCContext &Ctx) {
365    return Create(LAnd, LHS, RHS, Ctx);
366  }
367  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
368                                       MCContext &Ctx) {
369    return Create(LOr, LHS, RHS, Ctx);
370  }
371  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
372                                      MCContext &Ctx) {
373    return Create(LT, LHS, RHS, Ctx);
374  }
375  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
376                                       MCContext &Ctx) {
377    return Create(LTE, LHS, RHS, Ctx);
378  }
379  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
380                                       MCContext &Ctx) {
381    return Create(Mod, LHS, RHS, Ctx);
382  }
383  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
384                                       MCContext &Ctx) {
385    return Create(Mul, LHS, RHS, Ctx);
386  }
387  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
388                                      MCContext &Ctx) {
389    return Create(NE, LHS, RHS, Ctx);
390  }
391  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
392                                      MCContext &Ctx) {
393    return Create(Or, LHS, RHS, Ctx);
394  }
395  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
396                                       MCContext &Ctx) {
397    return Create(Shl, LHS, RHS, Ctx);
398  }
399  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
400                                       MCContext &Ctx) {
401    return Create(Shr, LHS, RHS, Ctx);
402  }
403  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
404                                       MCContext &Ctx) {
405    return Create(Sub, LHS, RHS, Ctx);
406  }
407  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
408                                       MCContext &Ctx) {
409    return Create(Xor, LHS, RHS, Ctx);
410  }
411
412  /// @}
413  /// @name Accessors
414  /// @{
415
416  /// getOpcode - Get the kind of this binary expression.
417  Opcode getOpcode() const { return Op; }
418
419  /// getLHS - Get the left-hand side expression of the binary operator.
420  const MCExpr *getLHS() const { return LHS; }
421
422  /// getRHS - Get the right-hand side expression of the binary operator.
423  const MCExpr *getRHS() const { return RHS; }
424
425  /// @}
426
427  static bool classof(const MCExpr *E) {
428    return E->getKind() == MCExpr::Binary;
429  }
430  static bool classof(const MCBinaryExpr *) { return true; }
431};
432
433/// MCTargetExpr - This is an extension point for target-specific MCExpr
434/// subclasses to implement.
435///
436/// NOTE: All subclasses are required to have trivial destructors because
437/// MCExprs are bump pointer allocated and not destructed.
438class MCTargetExpr : public MCExpr {
439  virtual void Anchor();
440protected:
441  MCTargetExpr() : MCExpr(Target) {}
442  virtual ~MCTargetExpr() {}
443public:
444
445  virtual void PrintImpl(raw_ostream &OS) const = 0;
446  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
447                                         const MCAsmLayout *Layout) const = 0;
448  virtual void AddValueSymbols(MCAssembler *) const = 0;
449  virtual const MCSection *FindAssociatedSection() const = 0;
450
451  static bool classof(const MCExpr *E) {
452    return E->getKind() == MCExpr::Target;
453  }
454  static bool classof(const MCTargetExpr *) { return true; }
455};
456
457} // end namespace llvm
458
459#endif
460