MCExpr.h revision 639aa87bee77fe2d83f0978ae1eea53e49def324 
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 MCAsmLayout;
19class MCAssembler;
20class MCContext;
21class MCSection;
22class MCSectionData;
23class MCSymbol;
24class MCValue;
25class raw_ostream;
26class StringRef;
27typedef DenseMap<const MCSectionData*, uint64_t> SectionAddrMap;
28
29/// MCExpr - Base class for the full range of assembler expressions which are
30/// needed for parsing.
31class MCExpr {
32public:
33  enum ExprKind {
34    Binary,    ///< Binary expressions.
35    Constant,  ///< Constant expressions.
36    SymbolRef, ///< References to labels and assigned expressions.
37    Unary,     ///< Unary expressions.
38    Target     ///< Target specific expression.
39  };
40
41private:
42  ExprKind Kind;
43
44  MCExpr(const MCExpr&); // DO NOT IMPLEMENT
45  void operator=(const MCExpr&); // DO NOT IMPLEMENT
46
47  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
48                          const MCAsmLayout *Layout,
49                          const SectionAddrMap *Addrs) const;
50protected:
51  explicit MCExpr(ExprKind _Kind) : Kind(_Kind) {}
52
53  bool EvaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
54                                 const MCAsmLayout *Layout,
55                                 const SectionAddrMap *Addrs,
56                                 bool InSet) const;
57public:
58  /// @name Accessors
59  /// @{
60
61  ExprKind getKind() const { return Kind; }
62
63  /// @}
64  /// @name Utility Methods
65  /// @{
66
67  void print(raw_ostream &OS) const;
68  void dump() const;
69
70  /// @}
71  /// @name Expression Evaluation
72  /// @{
73
74  /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
75  ///
76  /// @param Res - The absolute value, if evaluation succeeds.
77  /// @param Layout - The assembler layout object to use for evaluating symbol
78  /// values. If not given, then only non-symbolic expressions will be
79  /// evaluated.
80  /// @result - True on success.
81  bool EvaluateAsAbsolute(int64_t &Res) const;
82  bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const;
83  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
84  bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout,
85                          const SectionAddrMap &Addrs) const;
86
87  /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
88  /// value, i.e. an expression of the fixed form (a - b + constant).
89  ///
90  /// @param Res - The relocatable value, if evaluation succeeds.
91  /// @param Layout - The assembler layout object to use for evaluating values.
92  /// @result - True on success.
93  bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout &Layout) const;
94
95  /// FindAssociatedSection - Find the "associated section" for this expression,
96  /// which is currently defined as the absolute section for constants, or
97  /// otherwise the section associated with the first defined symbol in the
98  /// expression.
99  const MCSection *FindAssociatedSection() const;
100
101  /// @}
102
103  static bool classof(const MCExpr *) { return true; }
104};
105
106inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
107  E.print(OS);
108  return OS;
109}
110
111//// MCConstantExpr - Represent a constant integer expression.
112class MCConstantExpr : public MCExpr {
113  int64_t Value;
114
115  explicit MCConstantExpr(int64_t _Value)
116    : MCExpr(MCExpr::Constant), Value(_Value) {}
117
118public:
119  /// @name Construction
120  /// @{
121
122  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
123
124  /// @}
125  /// @name Accessors
126  /// @{
127
128  int64_t getValue() const { return Value; }
129
130  /// @}
131
132  static bool classof(const MCExpr *E) {
133    return E->getKind() == MCExpr::Constant;
134  }
135  static bool classof(const MCConstantExpr *) { return true; }
136};
137
138/// MCSymbolRefExpr - Represent a reference to a symbol from inside an
139/// expression.
140///
141/// A symbol reference in an expression may be a use of a label, a use of an
142/// assembler variable (defined constant), or constitute an implicit definition
143/// of the symbol as external.
144class MCSymbolRefExpr : public MCExpr {
145public:
146  enum VariantKind {
147    VK_None,
148    VK_Invalid,
149
150    VK_GOT,
151    VK_GOTOFF,
152    VK_GOTPCREL,
153    VK_GOTTPOFF,
154    VK_INDNTPOFF,
155    VK_NTPOFF,
156    VK_GOTNTPOFF,
157    VK_PLT,
158    VK_TLSGD,
159    VK_TLSLD,
160    VK_TLSLDM,
161    VK_TPOFF,
162    VK_DTPOFF,
163    VK_TLVP,      // Mach-O thread local variable relocation
164    VK_SECREL,
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    VK_ARM_TARGET1,
173
174    VK_PPC_TOC,
175    VK_PPC_DARWIN_HA16,  // ha16(symbol)
176    VK_PPC_DARWIN_LO16,  // lo16(symbol)
177    VK_PPC_GAS_HA16,     // symbol@ha
178    VK_PPC_GAS_LO16,      // symbol@l
179
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_TLSLDM,
188    VK_Mips_DTPREL_HI,
189    VK_Mips_DTPREL_LO,
190    VK_Mips_GOTTPREL,
191    VK_Mips_TPREL_HI,
192    VK_Mips_TPREL_LO,
193    VK_Mips_GPOFF_HI,
194    VK_Mips_GPOFF_LO,
195    VK_Mips_GOT_DISP,
196    VK_Mips_GOT_PAGE,
197    VK_Mips_GOT_OFST
198  };
199
200private:
201  /// The symbol being referenced.
202  const MCSymbol *Symbol;
203
204  /// The symbol reference modifier.
205  const VariantKind Kind;
206
207  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
208    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {
209    assert(Symbol);
210  }
211
212public:
213  /// @name Construction
214  /// @{
215
216  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
217    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
218  }
219
220  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
221                                       MCContext &Ctx);
222  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
223                                       MCContext &Ctx);
224
225  /// @}
226  /// @name Accessors
227  /// @{
228
229  const MCSymbol &getSymbol() const { return *Symbol; }
230
231  VariantKind getKind() const { return Kind; }
232
233  /// @}
234  /// @name Static Utility Functions
235  /// @{
236
237  static StringRef getVariantKindName(VariantKind Kind);
238
239  static VariantKind getVariantKindForName(StringRef Name);
240
241  /// @}
242
243  static bool classof(const MCExpr *E) {
244    return E->getKind() == MCExpr::SymbolRef;
245  }
246  static bool classof(const MCSymbolRefExpr *) { return true; }
247};
248
249/// MCUnaryExpr - Unary assembler expressions.
250class MCUnaryExpr : public MCExpr {
251public:
252  enum Opcode {
253    LNot,  ///< Logical negation.
254    Minus, ///< Unary minus.
255    Not,   ///< Bitwise negation.
256    Plus   ///< Unary plus.
257  };
258
259private:
260  Opcode Op;
261  const MCExpr *Expr;
262
263  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
264    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
265
266public:
267  /// @name Construction
268  /// @{
269
270  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
271                                   MCContext &Ctx);
272  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
273    return Create(LNot, Expr, Ctx);
274  }
275  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
276    return Create(Minus, Expr, Ctx);
277  }
278  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
279    return Create(Not, Expr, Ctx);
280  }
281  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
282    return Create(Plus, Expr, Ctx);
283  }
284
285  /// @}
286  /// @name Accessors
287  /// @{
288
289  /// getOpcode - Get the kind of this unary expression.
290  Opcode getOpcode() const { return Op; }
291
292  /// getSubExpr - Get the child of this unary expression.
293  const MCExpr *getSubExpr() const { return Expr; }
294
295  /// @}
296
297  static bool classof(const MCExpr *E) {
298    return E->getKind() == MCExpr::Unary;
299  }
300  static bool classof(const MCUnaryExpr *) { return true; }
301};
302
303/// MCBinaryExpr - Binary assembler expressions.
304class MCBinaryExpr : public MCExpr {
305public:
306  enum Opcode {
307    Add,  ///< Addition.
308    And,  ///< Bitwise and.
309    Div,  ///< Signed division.
310    EQ,   ///< Equality comparison.
311    GT,   ///< Signed greater than comparison (result is either 0 or some
312          ///< target-specific non-zero value)
313    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
314          ///< some target-specific non-zero value).
315    LAnd, ///< Logical and.
316    LOr,  ///< Logical or.
317    LT,   ///< Signed less than comparison (result is either 0 or
318          ///< some target-specific non-zero value).
319    LTE,  ///< Signed less than or equal comparison (result is either 0 or
320          ///< some target-specific non-zero value).
321    Mod,  ///< Signed remainder.
322    Mul,  ///< Multiplication.
323    NE,   ///< Inequality comparison.
324    Or,   ///< Bitwise or.
325    Shl,  ///< Shift left.
326    Shr,  ///< Shift right (arithmetic or logical, depending on target)
327    Sub,  ///< Subtraction.
328    Xor   ///< Bitwise exclusive or.
329  };
330
331private:
332  Opcode Op;
333  const MCExpr *LHS, *RHS;
334
335  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
336    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
337
338public:
339  /// @name Construction
340  /// @{
341
342  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
343                                    const MCExpr *RHS, MCContext &Ctx);
344  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
345                                       MCContext &Ctx) {
346    return Create(Add, LHS, RHS, Ctx);
347  }
348  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
349                                       MCContext &Ctx) {
350    return Create(And, LHS, RHS, Ctx);
351  }
352  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
353                                       MCContext &Ctx) {
354    return Create(Div, LHS, RHS, Ctx);
355  }
356  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
357                                      MCContext &Ctx) {
358    return Create(EQ, LHS, RHS, Ctx);
359  }
360  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
361                                      MCContext &Ctx) {
362    return Create(GT, LHS, RHS, Ctx);
363  }
364  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
365                                       MCContext &Ctx) {
366    return Create(GTE, LHS, RHS, Ctx);
367  }
368  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
369                                        MCContext &Ctx) {
370    return Create(LAnd, LHS, RHS, Ctx);
371  }
372  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
373                                       MCContext &Ctx) {
374    return Create(LOr, LHS, RHS, Ctx);
375  }
376  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
377                                      MCContext &Ctx) {
378    return Create(LT, LHS, RHS, Ctx);
379  }
380  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
381                                       MCContext &Ctx) {
382    return Create(LTE, LHS, RHS, Ctx);
383  }
384  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
385                                       MCContext &Ctx) {
386    return Create(Mod, LHS, RHS, Ctx);
387  }
388  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
389                                       MCContext &Ctx) {
390    return Create(Mul, LHS, RHS, Ctx);
391  }
392  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
393                                      MCContext &Ctx) {
394    return Create(NE, LHS, RHS, Ctx);
395  }
396  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
397                                      MCContext &Ctx) {
398    return Create(Or, LHS, RHS, Ctx);
399  }
400  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
401                                       MCContext &Ctx) {
402    return Create(Shl, LHS, RHS, Ctx);
403  }
404  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
405                                       MCContext &Ctx) {
406    return Create(Shr, LHS, RHS, Ctx);
407  }
408  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
409                                       MCContext &Ctx) {
410    return Create(Sub, LHS, RHS, Ctx);
411  }
412  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
413                                       MCContext &Ctx) {
414    return Create(Xor, LHS, RHS, Ctx);
415  }
416
417  /// @}
418  /// @name Accessors
419  /// @{
420
421  /// getOpcode - Get the kind of this binary expression.
422  Opcode getOpcode() const { return Op; }
423
424  /// getLHS - Get the left-hand side expression of the binary operator.
425  const MCExpr *getLHS() const { return LHS; }
426
427  /// getRHS - Get the right-hand side expression of the binary operator.
428  const MCExpr *getRHS() const { return RHS; }
429
430  /// @}
431
432  static bool classof(const MCExpr *E) {
433    return E->getKind() == MCExpr::Binary;
434  }
435  static bool classof(const MCBinaryExpr *) { return true; }
436};
437
438/// MCTargetExpr - This is an extension point for target-specific MCExpr
439/// subclasses to implement.
440///
441/// NOTE: All subclasses are required to have trivial destructors because
442/// MCExprs are bump pointer allocated and not destructed.
443class MCTargetExpr : public MCExpr {
444  virtual void Anchor();
445protected:
446  MCTargetExpr() : MCExpr(Target) {}
447  virtual ~MCTargetExpr() {}
448public:
449
450  virtual void PrintImpl(raw_ostream &OS) const = 0;
451  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
452                                         const MCAsmLayout *Layout) const = 0;
453  virtual void AddValueSymbols(MCAssembler *) const = 0;
454  virtual const MCSection *FindAssociatedSection() const = 0;
455
456  static bool classof(const MCExpr *E) {
457    return E->getKind() == MCExpr::Target;
458  }
459  static bool classof(const MCTargetExpr *) { return true; }
460};
461
462} // end namespace llvm
463
464#endif
465