• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 
17 namespace llvm {
18 class MCAsmInfo;
19 class MCAsmLayout;
20 class MCAssembler;
21 class MCContext;
22 class MCSection;
23 class MCSectionData;
24 class MCStreamer;
25 class MCSymbol;
26 class MCValue;
27 class raw_ostream;
28 class StringRef;
29 typedef DenseMap<const MCSectionData*, uint64_t> SectionAddrMap;
30 
31 /// MCExpr - Base class for the full range of assembler expressions which are
32 /// needed for parsing.
33 class MCExpr {
34 public:
35   enum ExprKind {
36     Binary,    ///< Binary expressions.
37     Constant,  ///< Constant expressions.
38     SymbolRef, ///< References to labels and assigned expressions.
39     Unary,     ///< Unary expressions.
40     Target     ///< Target specific expression.
41   };
42 
43 private:
44   ExprKind Kind;
45 
46   MCExpr(const MCExpr&) LLVM_DELETED_FUNCTION;
47   void operator=(const MCExpr&) LLVM_DELETED_FUNCTION;
48 
49   bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
50                           const MCAsmLayout *Layout,
51                           const SectionAddrMap *Addrs) const;
52 protected:
MCExpr(ExprKind _Kind)53   explicit MCExpr(ExprKind _Kind) : Kind(_Kind) {}
54 
55   bool EvaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
56                                  const MCAsmLayout *Layout,
57                                  const SectionAddrMap *Addrs, bool InSet,
58                                  bool ForceVarExpansion) const;
59 
60 public:
61   /// @name Accessors
62   /// @{
63 
getKind()64   ExprKind getKind() const { return Kind; }
65 
66   /// @}
67   /// @name Utility Methods
68   /// @{
69 
70   void print(raw_ostream &OS) const;
71   void dump() const;
72 
73   /// @}
74   /// @name Expression Evaluation
75   /// @{
76 
77   /// EvaluateAsAbsolute - Try to evaluate the expression to an absolute value.
78   ///
79   /// @param Res - The absolute value, if evaluation succeeds.
80   /// @param Layout - The assembler layout object to use for evaluating symbol
81   /// values. If not given, then only non-symbolic expressions will be
82   /// evaluated.
83   /// @result - True on success.
84   bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout,
85                           const SectionAddrMap &Addrs) const;
86   bool EvaluateAsAbsolute(int64_t &Res) const;
87   bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const;
88   bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
89 
90   /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
91   /// value, i.e. an expression of the fixed form (a - b + constant).
92   ///
93   /// @param Res - The relocatable value, if evaluation succeeds.
94   /// @param Layout - The assembler layout object to use for evaluating values.
95   /// @result - True on success.
96   bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout *Layout) const;
97 
98   /// \brief Try to evaluate the expression to the form (a - b + constant) where
99   /// neither a nor b are variables.
100   ///
101   /// This is a more aggressive variant of EvaluateAsRelocatable. The intended
102   /// use is for when relocations are not available, like the symbol value in
103   /// the symbol table.
104   bool EvaluateAsValue(MCValue &Res, const MCAsmLayout *Layout) const;
105 
106   /// FindAssociatedSection - Find the "associated section" for this expression,
107   /// which is currently defined as the absolute section for constants, or
108   /// otherwise the section associated with the first defined symbol in the
109   /// expression.
110   const MCSection *FindAssociatedSection() const;
111 
112   /// @}
113 };
114 
115 inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
116   E.print(OS);
117   return OS;
118 }
119 
120 //// MCConstantExpr - Represent a constant integer expression.
121 class MCConstantExpr : public MCExpr {
122   int64_t Value;
123 
MCConstantExpr(int64_t _Value)124   explicit MCConstantExpr(int64_t _Value)
125     : MCExpr(MCExpr::Constant), Value(_Value) {}
126 
127 public:
128   /// @name Construction
129   /// @{
130 
131   static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
132 
133   /// @}
134   /// @name Accessors
135   /// @{
136 
getValue()137   int64_t getValue() const { return Value; }
138 
139   /// @}
140 
classof(const MCExpr * E)141   static bool classof(const MCExpr *E) {
142     return E->getKind() == MCExpr::Constant;
143   }
144 };
145 
146 /// MCSymbolRefExpr - Represent a reference to a symbol from inside an
147 /// expression.
148 ///
149 /// A symbol reference in an expression may be a use of a label, a use of an
150 /// assembler variable (defined constant), or constitute an implicit definition
151 /// of the symbol as external.
152 class MCSymbolRefExpr : public MCExpr {
153 public:
154   enum VariantKind {
155     VK_None,
156     VK_Invalid,
157 
158     VK_GOT,
159     VK_GOTOFF,
160     VK_GOTPCREL,
161     VK_GOTTPOFF,
162     VK_INDNTPOFF,
163     VK_NTPOFF,
164     VK_GOTNTPOFF,
165     VK_PLT,
166     VK_TLSGD,
167     VK_TLSLD,
168     VK_TLSLDM,
169     VK_TPOFF,
170     VK_DTPOFF,
171     VK_TLVP,      // Mach-O thread local variable relocations
172     VK_TLVPPAGE,
173     VK_TLVPPAGEOFF,
174     VK_PAGE,
175     VK_PAGEOFF,
176     VK_GOTPAGE,
177     VK_GOTPAGEOFF,
178     VK_SECREL,
179     VK_WEAKREF,   // The link between the symbols in .weakref foo, bar
180 
181     VK_ARM_NONE,
182     VK_ARM_TARGET1,
183     VK_ARM_TARGET2,
184     VK_ARM_PREL31,
185     VK_ARM_TLSLDO,         // symbol(tlsldo)
186     VK_ARM_TLSCALL,        // symbol(tlscall)
187     VK_ARM_TLSDESC,        // symbol(tlsdesc)
188     VK_ARM_TLSDESCSEQ,
189 
190     VK_PPC_LO,             // symbol@l
191     VK_PPC_HI,             // symbol@h
192     VK_PPC_HA,             // symbol@ha
193     VK_PPC_HIGHER,         // symbol@higher
194     VK_PPC_HIGHERA,        // symbol@highera
195     VK_PPC_HIGHEST,        // symbol@highest
196     VK_PPC_HIGHESTA,       // symbol@highesta
197     VK_PPC_GOT_LO,         // symbol@got@l
198     VK_PPC_GOT_HI,         // symbol@got@h
199     VK_PPC_GOT_HA,         // symbol@got@ha
200     VK_PPC_TOCBASE,        // symbol@tocbase
201     VK_PPC_TOC,            // symbol@toc
202     VK_PPC_TOC_LO,         // symbol@toc@l
203     VK_PPC_TOC_HI,         // symbol@toc@h
204     VK_PPC_TOC_HA,         // symbol@toc@ha
205     VK_PPC_DTPMOD,         // symbol@dtpmod
206     VK_PPC_TPREL,          // symbol@tprel
207     VK_PPC_TPREL_LO,       // symbol@tprel@l
208     VK_PPC_TPREL_HI,       // symbol@tprel@h
209     VK_PPC_TPREL_HA,       // symbol@tprel@ha
210     VK_PPC_TPREL_HIGHER,   // symbol@tprel@higher
211     VK_PPC_TPREL_HIGHERA,  // symbol@tprel@highera
212     VK_PPC_TPREL_HIGHEST,  // symbol@tprel@highest
213     VK_PPC_TPREL_HIGHESTA, // symbol@tprel@highesta
214     VK_PPC_DTPREL,         // symbol@dtprel
215     VK_PPC_DTPREL_LO,      // symbol@dtprel@l
216     VK_PPC_DTPREL_HI,      // symbol@dtprel@h
217     VK_PPC_DTPREL_HA,      // symbol@dtprel@ha
218     VK_PPC_DTPREL_HIGHER,  // symbol@dtprel@higher
219     VK_PPC_DTPREL_HIGHERA, // symbol@dtprel@highera
220     VK_PPC_DTPREL_HIGHEST, // symbol@dtprel@highest
221     VK_PPC_DTPREL_HIGHESTA,// symbol@dtprel@highesta
222     VK_PPC_GOT_TPREL,      // symbol@got@tprel
223     VK_PPC_GOT_TPREL_LO,   // symbol@got@tprel@l
224     VK_PPC_GOT_TPREL_HI,   // symbol@got@tprel@h
225     VK_PPC_GOT_TPREL_HA,   // symbol@got@tprel@ha
226     VK_PPC_GOT_DTPREL,     // symbol@got@dtprel
227     VK_PPC_GOT_DTPREL_LO,  // symbol@got@dtprel@l
228     VK_PPC_GOT_DTPREL_HI,  // symbol@got@dtprel@h
229     VK_PPC_GOT_DTPREL_HA,  // symbol@got@dtprel@ha
230     VK_PPC_TLS,            // symbol@tls
231     VK_PPC_GOT_TLSGD,      // symbol@got@tlsgd
232     VK_PPC_GOT_TLSGD_LO,   // symbol@got@tlsgd@l
233     VK_PPC_GOT_TLSGD_HI,   // symbol@got@tlsgd@h
234     VK_PPC_GOT_TLSGD_HA,   // symbol@got@tlsgd@ha
235     VK_PPC_TLSGD,          // symbol@tlsgd
236     VK_PPC_GOT_TLSLD,      // symbol@got@tlsld
237     VK_PPC_GOT_TLSLD_LO,   // symbol@got@tlsld@l
238     VK_PPC_GOT_TLSLD_HI,   // symbol@got@tlsld@h
239     VK_PPC_GOT_TLSLD_HA,   // symbol@got@tlsld@ha
240     VK_PPC_TLSLD,          // symbol@tlsld
241 
242     VK_Mips_GPREL,
243     VK_Mips_GOT_CALL,
244     VK_Mips_GOT16,
245     VK_Mips_GOT,
246     VK_Mips_ABS_HI,
247     VK_Mips_ABS_LO,
248     VK_Mips_TLSGD,
249     VK_Mips_TLSLDM,
250     VK_Mips_DTPREL_HI,
251     VK_Mips_DTPREL_LO,
252     VK_Mips_GOTTPREL,
253     VK_Mips_TPREL_HI,
254     VK_Mips_TPREL_LO,
255     VK_Mips_GPOFF_HI,
256     VK_Mips_GPOFF_LO,
257     VK_Mips_GOT_DISP,
258     VK_Mips_GOT_PAGE,
259     VK_Mips_GOT_OFST,
260     VK_Mips_HIGHER,
261     VK_Mips_HIGHEST,
262     VK_Mips_GOT_HI16,
263     VK_Mips_GOT_LO16,
264     VK_Mips_CALL_HI16,
265     VK_Mips_CALL_LO16,
266     VK_Mips_PCREL_HI16,
267     VK_Mips_PCREL_LO16,
268 
269     VK_COFF_IMGREL32 // symbol@imgrel (image-relative)
270   };
271 
272 private:
273   /// The symbol being referenced.
274   const MCSymbol *Symbol;
275 
276   /// The symbol reference modifier.
277   const VariantKind Kind;
278 
279   /// MCAsmInfo that is used to print symbol variants correctly.
280   const MCAsmInfo *MAI;
281 
MCSymbolRefExpr(const MCSymbol * _Symbol,VariantKind _Kind,const MCAsmInfo * _MAI)282   explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind,
283                            const MCAsmInfo *_MAI)
284     : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind), MAI(_MAI) {
285     assert(Symbol);
286     assert(MAI);
287   }
288 
289 public:
290   /// @name Construction
291   /// @{
292 
Create(const MCSymbol * Symbol,MCContext & Ctx)293   static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
294     return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
295   }
296 
297   static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
298                                        MCContext &Ctx);
299   static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
300                                        MCContext &Ctx);
301 
302   /// @}
303   /// @name Accessors
304   /// @{
305 
getSymbol()306   const MCSymbol &getSymbol() const { return *Symbol; }
getMCAsmInfo()307   const MCAsmInfo &getMCAsmInfo() const { return *MAI; }
308 
getKind()309   VariantKind getKind() const { return Kind; }
310 
311   /// @}
312   /// @name Static Utility Functions
313   /// @{
314 
315   static StringRef getVariantKindName(VariantKind Kind);
316 
317   static VariantKind getVariantKindForName(StringRef Name);
318 
319   /// @}
320 
classof(const MCExpr * E)321   static bool classof(const MCExpr *E) {
322     return E->getKind() == MCExpr::SymbolRef;
323   }
324 };
325 
326 /// MCUnaryExpr - Unary assembler expressions.
327 class MCUnaryExpr : public MCExpr {
328 public:
329   enum Opcode {
330     LNot,  ///< Logical negation.
331     Minus, ///< Unary minus.
332     Not,   ///< Bitwise negation.
333     Plus   ///< Unary plus.
334   };
335 
336 private:
337   Opcode Op;
338   const MCExpr *Expr;
339 
MCUnaryExpr(Opcode _Op,const MCExpr * _Expr)340   MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
341     : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
342 
343 public:
344   /// @name Construction
345   /// @{
346 
347   static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
348                                    MCContext &Ctx);
CreateLNot(const MCExpr * Expr,MCContext & Ctx)349   static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
350     return Create(LNot, Expr, Ctx);
351   }
CreateMinus(const MCExpr * Expr,MCContext & Ctx)352   static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
353     return Create(Minus, Expr, Ctx);
354   }
CreateNot(const MCExpr * Expr,MCContext & Ctx)355   static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
356     return Create(Not, Expr, Ctx);
357   }
CreatePlus(const MCExpr * Expr,MCContext & Ctx)358   static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
359     return Create(Plus, Expr, Ctx);
360   }
361 
362   /// @}
363   /// @name Accessors
364   /// @{
365 
366   /// getOpcode - Get the kind of this unary expression.
getOpcode()367   Opcode getOpcode() const { return Op; }
368 
369   /// getSubExpr - Get the child of this unary expression.
getSubExpr()370   const MCExpr *getSubExpr() const { return Expr; }
371 
372   /// @}
373 
classof(const MCExpr * E)374   static bool classof(const MCExpr *E) {
375     return E->getKind() == MCExpr::Unary;
376   }
377 };
378 
379 /// MCBinaryExpr - Binary assembler expressions.
380 class MCBinaryExpr : public MCExpr {
381 public:
382   enum Opcode {
383     Add,  ///< Addition.
384     And,  ///< Bitwise and.
385     Div,  ///< Signed division.
386     EQ,   ///< Equality comparison.
387     GT,   ///< Signed greater than comparison (result is either 0 or some
388           ///< target-specific non-zero value)
389     GTE,  ///< Signed greater than or equal comparison (result is either 0 or
390           ///< some target-specific non-zero value).
391     LAnd, ///< Logical and.
392     LOr,  ///< Logical or.
393     LT,   ///< Signed less than comparison (result is either 0 or
394           ///< some target-specific non-zero value).
395     LTE,  ///< Signed less than or equal comparison (result is either 0 or
396           ///< some target-specific non-zero value).
397     Mod,  ///< Signed remainder.
398     Mul,  ///< Multiplication.
399     NE,   ///< Inequality comparison.
400     Or,   ///< Bitwise or.
401     Shl,  ///< Shift left.
402     Shr,  ///< Shift right (arithmetic or logical, depending on target)
403     Sub,  ///< Subtraction.
404     Xor   ///< Bitwise exclusive or.
405   };
406 
407 private:
408   Opcode Op;
409   const MCExpr *LHS, *RHS;
410 
MCBinaryExpr(Opcode _Op,const MCExpr * _LHS,const MCExpr * _RHS)411   MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
412     : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
413 
414 public:
415   /// @name Construction
416   /// @{
417 
418   static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
419                                     const MCExpr *RHS, MCContext &Ctx);
CreateAdd(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)420   static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
421                                        MCContext &Ctx) {
422     return Create(Add, LHS, RHS, Ctx);
423   }
CreateAnd(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)424   static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
425                                        MCContext &Ctx) {
426     return Create(And, LHS, RHS, Ctx);
427   }
CreateDiv(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)428   static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
429                                        MCContext &Ctx) {
430     return Create(Div, LHS, RHS, Ctx);
431   }
CreateEQ(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)432   static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
433                                       MCContext &Ctx) {
434     return Create(EQ, LHS, RHS, Ctx);
435   }
CreateGT(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)436   static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
437                                       MCContext &Ctx) {
438     return Create(GT, LHS, RHS, Ctx);
439   }
CreateGTE(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)440   static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
441                                        MCContext &Ctx) {
442     return Create(GTE, LHS, RHS, Ctx);
443   }
CreateLAnd(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)444   static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
445                                         MCContext &Ctx) {
446     return Create(LAnd, LHS, RHS, Ctx);
447   }
CreateLOr(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)448   static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
449                                        MCContext &Ctx) {
450     return Create(LOr, LHS, RHS, Ctx);
451   }
CreateLT(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)452   static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
453                                       MCContext &Ctx) {
454     return Create(LT, LHS, RHS, Ctx);
455   }
CreateLTE(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)456   static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
457                                        MCContext &Ctx) {
458     return Create(LTE, LHS, RHS, Ctx);
459   }
CreateMod(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)460   static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
461                                        MCContext &Ctx) {
462     return Create(Mod, LHS, RHS, Ctx);
463   }
CreateMul(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)464   static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
465                                        MCContext &Ctx) {
466     return Create(Mul, LHS, RHS, Ctx);
467   }
CreateNE(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)468   static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
469                                       MCContext &Ctx) {
470     return Create(NE, LHS, RHS, Ctx);
471   }
CreateOr(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)472   static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
473                                       MCContext &Ctx) {
474     return Create(Or, LHS, RHS, Ctx);
475   }
CreateShl(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)476   static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
477                                        MCContext &Ctx) {
478     return Create(Shl, LHS, RHS, Ctx);
479   }
CreateShr(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)480   static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
481                                        MCContext &Ctx) {
482     return Create(Shr, LHS, RHS, Ctx);
483   }
CreateSub(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)484   static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
485                                        MCContext &Ctx) {
486     return Create(Sub, LHS, RHS, Ctx);
487   }
CreateXor(const MCExpr * LHS,const MCExpr * RHS,MCContext & Ctx)488   static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
489                                        MCContext &Ctx) {
490     return Create(Xor, LHS, RHS, Ctx);
491   }
492 
493   /// @}
494   /// @name Accessors
495   /// @{
496 
497   /// getOpcode - Get the kind of this binary expression.
getOpcode()498   Opcode getOpcode() const { return Op; }
499 
500   /// getLHS - Get the left-hand side expression of the binary operator.
getLHS()501   const MCExpr *getLHS() const { return LHS; }
502 
503   /// getRHS - Get the right-hand side expression of the binary operator.
getRHS()504   const MCExpr *getRHS() const { return RHS; }
505 
506   /// @}
507 
classof(const MCExpr * E)508   static bool classof(const MCExpr *E) {
509     return E->getKind() == MCExpr::Binary;
510   }
511 };
512 
513 /// MCTargetExpr - This is an extension point for target-specific MCExpr
514 /// subclasses to implement.
515 ///
516 /// NOTE: All subclasses are required to have trivial destructors because
517 /// MCExprs are bump pointer allocated and not destructed.
518 class MCTargetExpr : public MCExpr {
519   virtual void anchor();
520 protected:
MCTargetExpr()521   MCTargetExpr() : MCExpr(Target) {}
~MCTargetExpr()522   virtual ~MCTargetExpr() {}
523 public:
524 
525   virtual void PrintImpl(raw_ostream &OS) const = 0;
526   virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
527                                          const MCAsmLayout *Layout) const = 0;
528   virtual void visitUsedExpr(MCStreamer& Streamer) const = 0;
529   virtual const MCSection *FindAssociatedSection() const = 0;
530 
531   virtual void fixELFSymbolsInTLSFixups(MCAssembler &) const = 0;
532 
classof(const MCExpr * E)533   static bool classof(const MCExpr *E) {
534     return E->getKind() == MCExpr::Target;
535   }
536 };
537 
538 } // end namespace llvm
539 
540 #endif
541