MCExpr.h revision cd81d94322a39503e4a3e87b6ee03d4fcb3465fb 
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 MCStreamer;
25class MCSymbol;
26class MCValue;
27class raw_ostream;
28class StringRef;
29typedef DenseMap<const MCSectionData*, uint64_t> SectionAddrMap;
30
31/// MCExpr - Base class for the full range of assembler expressions which are
32/// needed for parsing.
33class MCExpr {
34public:
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
43private:
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;
52protected:
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
60public:
61  /// @name Accessors
62  /// @{
63
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
115inline 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.
121class MCConstantExpr : public MCExpr {
122  int64_t Value;
123
124  explicit MCConstantExpr(int64_t _Value)
125    : MCExpr(MCExpr::Constant), Value(_Value) {}
126
127public:
128  /// @name Construction
129  /// @{
130
131  static const MCConstantExpr *Create(int64_t Value, MCContext &Ctx);
132
133  /// @}
134  /// @name Accessors
135  /// @{
136
137  int64_t getValue() const { return Value; }
138
139  /// @}
140
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.
152class MCSymbolRefExpr : public MCExpr {
153public:
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
272private:
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
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
289public:
290  /// @name Construction
291  /// @{
292
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
306  const MCSymbol &getSymbol() const { return *Symbol; }
307  const MCAsmInfo &getMCAsmInfo() const { return *MAI; }
308
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
321  static bool classof(const MCExpr *E) {
322    return E->getKind() == MCExpr::SymbolRef;
323  }
324};
325
326/// MCUnaryExpr - Unary assembler expressions.
327class MCUnaryExpr : public MCExpr {
328public:
329  enum Opcode {
330    LNot,  ///< Logical negation.
331    Minus, ///< Unary minus.
332    Not,   ///< Bitwise negation.
333    Plus   ///< Unary plus.
334  };
335
336private:
337  Opcode Op;
338  const MCExpr *Expr;
339
340  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
341    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
342
343public:
344  /// @name Construction
345  /// @{
346
347  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
348                                   MCContext &Ctx);
349  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
350    return Create(LNot, Expr, Ctx);
351  }
352  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
353    return Create(Minus, Expr, Ctx);
354  }
355  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
356    return Create(Not, Expr, Ctx);
357  }
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.
367  Opcode getOpcode() const { return Op; }
368
369  /// getSubExpr - Get the child of this unary expression.
370  const MCExpr *getSubExpr() const { return Expr; }
371
372  /// @}
373
374  static bool classof(const MCExpr *E) {
375    return E->getKind() == MCExpr::Unary;
376  }
377};
378
379/// MCBinaryExpr - Binary assembler expressions.
380class MCBinaryExpr : public MCExpr {
381public:
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
407private:
408  Opcode Op;
409  const MCExpr *LHS, *RHS;
410
411  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
412    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
413
414public:
415  /// @name Construction
416  /// @{
417
418  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
419                                    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  }
424  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
425                                       MCContext &Ctx) {
426    return Create(And, LHS, RHS, Ctx);
427  }
428  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
429                                       MCContext &Ctx) {
430    return Create(Div, LHS, RHS, Ctx);
431  }
432  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
433                                      MCContext &Ctx) {
434    return Create(EQ, LHS, RHS, Ctx);
435  }
436  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
437                                      MCContext &Ctx) {
438    return Create(GT, LHS, RHS, Ctx);
439  }
440  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
441                                       MCContext &Ctx) {
442    return Create(GTE, LHS, RHS, Ctx);
443  }
444  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
445                                        MCContext &Ctx) {
446    return Create(LAnd, LHS, RHS, Ctx);
447  }
448  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
449                                       MCContext &Ctx) {
450    return Create(LOr, LHS, RHS, Ctx);
451  }
452  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
453                                      MCContext &Ctx) {
454    return Create(LT, LHS, RHS, Ctx);
455  }
456  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
457                                       MCContext &Ctx) {
458    return Create(LTE, LHS, RHS, Ctx);
459  }
460  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
461                                       MCContext &Ctx) {
462    return Create(Mod, LHS, RHS, Ctx);
463  }
464  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
465                                       MCContext &Ctx) {
466    return Create(Mul, LHS, RHS, Ctx);
467  }
468  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
469                                      MCContext &Ctx) {
470    return Create(NE, LHS, RHS, Ctx);
471  }
472  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
473                                      MCContext &Ctx) {
474    return Create(Or, LHS, RHS, Ctx);
475  }
476  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
477                                       MCContext &Ctx) {
478    return Create(Shl, LHS, RHS, Ctx);
479  }
480  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
481                                       MCContext &Ctx) {
482    return Create(Shr, LHS, RHS, Ctx);
483  }
484  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
485                                       MCContext &Ctx) {
486    return Create(Sub, LHS, RHS, Ctx);
487  }
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.
498  Opcode getOpcode() const { return Op; }
499
500  /// getLHS - Get the left-hand side expression of the binary operator.
501  const MCExpr *getLHS() const { return LHS; }
502
503  /// getRHS - Get the right-hand side expression of the binary operator.
504  const MCExpr *getRHS() const { return RHS; }
505
506  /// @}
507
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.
518class MCTargetExpr : public MCExpr {
519  virtual void anchor();
520protected:
521  MCTargetExpr() : MCExpr(Target) {}
522  virtual ~MCTargetExpr() {}
523public:
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
533  static bool classof(const MCExpr *E) {
534    return E->getKind() == MCExpr::Target;
535  }
536};
537
538} // end namespace llvm
539
540#endif
541