MCExpr.h revision de2d8694e25a814696358e95141f4b1aa4d8847e 
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 MCFixup;
23class MCFragment;
24class MCSection;
25class MCStreamer;
26class MCSymbol;
27class MCValue;
28class raw_ostream;
29class StringRef;
30typedef DenseMap<const MCSection *, uint64_t> SectionAddrMap;
31
32/// \brief Base class for the full range of assembler expressions which are
33/// needed for parsing.
34class MCExpr {
35public:
36  enum ExprKind {
37    Binary,    ///< Binary expressions.
38    Constant,  ///< Constant expressions.
39    SymbolRef, ///< References to labels and assigned expressions.
40    Unary,     ///< Unary expressions.
41    Target     ///< Target specific expression.
42  };
43
44private:
45  ExprKind Kind;
46
47  MCExpr(const MCExpr&) = delete;
48  void operator=(const MCExpr&) = delete;
49
50  bool evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
51                          const MCAsmLayout *Layout,
52                          const SectionAddrMap *Addrs) const;
53
54  bool evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
55                          const MCAsmLayout *Layout,
56                          const SectionAddrMap *Addrs, bool InSet) const;
57
58protected:
59  explicit MCExpr(ExprKind Kind) : Kind(Kind) {}
60
61  bool evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
62                                 const MCAsmLayout *Layout,
63                                 const MCFixup *Fixup,
64                                 const SectionAddrMap *Addrs, bool InSet) const;
65
66public:
67  /// \name Accessors
68  /// @{
69
70  ExprKind getKind() const { return Kind; }
71
72  /// @}
73  /// \name Utility Methods
74  /// @{
75
76  void print(raw_ostream &OS, const MCAsmInfo *MAI,
77             bool InParens = false) const;
78  void dump() const;
79
80  /// @}
81  /// \name Expression Evaluation
82  /// @{
83
84  /// \brief Try to evaluate the expression to an absolute value.
85  ///
86  /// \param Res - The absolute value, if evaluation succeeds.
87  /// \param Layout - The assembler layout object to use for evaluating symbol
88  /// values. If not given, then only non-symbolic expressions will be
89  /// evaluated.
90  /// \return - True on success.
91  bool evaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout,
92                          const SectionAddrMap &Addrs) const;
93  bool evaluateAsAbsolute(int64_t &Res) const;
94  bool evaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const;
95  bool evaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
96
97  bool evaluateKnownAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
98
99  /// \brief Try to evaluate the expression to a relocatable value, i.e. an
100  /// expression of the fixed form (a - b + constant).
101  ///
102  /// \param Res - The relocatable value, if evaluation succeeds.
103  /// \param Layout - The assembler layout object to use for evaluating values.
104  /// \param Fixup - The Fixup object if available.
105  /// \return - True on success.
106  bool evaluateAsRelocatable(MCValue &Res, const MCAsmLayout *Layout,
107                             const MCFixup *Fixup) const;
108
109  /// \brief Try to evaluate the expression to the form (a - b + constant) where
110  /// neither a nor b are variables.
111  ///
112  /// This is a more aggressive variant of evaluateAsRelocatable. The intended
113  /// use is for when relocations are not available, like the .size directive.
114  bool evaluateAsValue(MCValue &Res, const MCAsmLayout &Layout) const;
115
116  /// \brief Find the "associated section" for this expression, which is
117  /// currently defined as the absolute section for constants, or
118  /// otherwise the section associated with the first defined symbol in the
119  /// expression.
120  MCFragment *findAssociatedFragment() const;
121
122  /// @}
123};
124
125inline raw_ostream &operator<<(raw_ostream &OS, const MCExpr &E) {
126  E.print(OS, nullptr);
127  return OS;
128}
129
130//// \brief  Represent a constant integer expression.
131class MCConstantExpr : public MCExpr {
132  int64_t Value;
133
134  explicit MCConstantExpr(int64_t Value)
135      : MCExpr(MCExpr::Constant), Value(Value) {}
136
137public:
138  /// \name Construction
139  /// @{
140
141  static const MCConstantExpr *create(int64_t Value, MCContext &Ctx);
142
143  /// @}
144  /// \name Accessors
145  /// @{
146
147  int64_t getValue() const { return Value; }
148
149  /// @}
150
151  static bool classof(const MCExpr *E) {
152    return E->getKind() == MCExpr::Constant;
153  }
154};
155
156/// \brief  Represent a reference to a symbol from inside an expression.
157///
158/// A symbol reference in an expression may be a use of a label, a use of an
159/// assembler variable (defined constant), or constitute an implicit definition
160/// of the symbol as external.
161class MCSymbolRefExpr : public MCExpr {
162public:
163  enum VariantKind : uint16_t {
164    VK_None,
165    VK_Invalid,
166
167    VK_GOT,
168    VK_GOTOFF,
169    VK_GOTREL,
170    VK_GOTPCREL,
171    VK_GOTTPOFF,
172    VK_INDNTPOFF,
173    VK_NTPOFF,
174    VK_GOTNTPOFF,
175    VK_PLT,
176    VK_TLSGD,
177    VK_TLSLD,
178    VK_TLSLDM,
179    VK_TPOFF,
180    VK_DTPOFF,
181    VK_TLSCALL,   // symbol(tlscall)
182    VK_TLSDESC,   // symbol(tlsdesc)
183    VK_TLVP,      // Mach-O thread local variable relocations
184    VK_TLVPPAGE,
185    VK_TLVPPAGEOFF,
186    VK_PAGE,
187    VK_PAGEOFF,
188    VK_GOTPAGE,
189    VK_GOTPAGEOFF,
190    VK_SECREL,
191    VK_SIZE,      // symbol@SIZE
192    VK_WEAKREF,   // The link between the symbols in .weakref foo, bar
193
194    VK_ARM_NONE,
195    VK_ARM_GOT_PREL,
196    VK_ARM_TARGET1,
197    VK_ARM_TARGET2,
198    VK_ARM_PREL31,
199    VK_ARM_SBREL,          // symbol(sbrel)
200    VK_ARM_TLSLDO,         // symbol(tlsldo)
201    VK_ARM_TLSDESCSEQ,
202
203    VK_PPC_LO,             // symbol@l
204    VK_PPC_HI,             // symbol@h
205    VK_PPC_HA,             // symbol@ha
206    VK_PPC_HIGHER,         // symbol@higher
207    VK_PPC_HIGHERA,        // symbol@highera
208    VK_PPC_HIGHEST,        // symbol@highest
209    VK_PPC_HIGHESTA,       // symbol@highesta
210    VK_PPC_GOT_LO,         // symbol@got@l
211    VK_PPC_GOT_HI,         // symbol@got@h
212    VK_PPC_GOT_HA,         // symbol@got@ha
213    VK_PPC_TOCBASE,        // symbol@tocbase
214    VK_PPC_TOC,            // symbol@toc
215    VK_PPC_TOC_LO,         // symbol@toc@l
216    VK_PPC_TOC_HI,         // symbol@toc@h
217    VK_PPC_TOC_HA,         // symbol@toc@ha
218    VK_PPC_DTPMOD,         // symbol@dtpmod
219    VK_PPC_TPREL_LO,       // symbol@tprel@l
220    VK_PPC_TPREL_HI,       // symbol@tprel@h
221    VK_PPC_TPREL_HA,       // symbol@tprel@ha
222    VK_PPC_TPREL_HIGHER,   // symbol@tprel@higher
223    VK_PPC_TPREL_HIGHERA,  // symbol@tprel@highera
224    VK_PPC_TPREL_HIGHEST,  // symbol@tprel@highest
225    VK_PPC_TPREL_HIGHESTA, // symbol@tprel@highesta
226    VK_PPC_DTPREL_LO,      // symbol@dtprel@l
227    VK_PPC_DTPREL_HI,      // symbol@dtprel@h
228    VK_PPC_DTPREL_HA,      // symbol@dtprel@ha
229    VK_PPC_DTPREL_HIGHER,  // symbol@dtprel@higher
230    VK_PPC_DTPREL_HIGHERA, // symbol@dtprel@highera
231    VK_PPC_DTPREL_HIGHEST, // symbol@dtprel@highest
232    VK_PPC_DTPREL_HIGHESTA,// symbol@dtprel@highesta
233    VK_PPC_GOT_TPREL,      // symbol@got@tprel
234    VK_PPC_GOT_TPREL_LO,   // symbol@got@tprel@l
235    VK_PPC_GOT_TPREL_HI,   // symbol@got@tprel@h
236    VK_PPC_GOT_TPREL_HA,   // symbol@got@tprel@ha
237    VK_PPC_GOT_DTPREL,     // symbol@got@dtprel
238    VK_PPC_GOT_DTPREL_LO,  // symbol@got@dtprel@l
239    VK_PPC_GOT_DTPREL_HI,  // symbol@got@dtprel@h
240    VK_PPC_GOT_DTPREL_HA,  // symbol@got@dtprel@ha
241    VK_PPC_TLS,            // symbol@tls
242    VK_PPC_GOT_TLSGD,      // symbol@got@tlsgd
243    VK_PPC_GOT_TLSGD_LO,   // symbol@got@tlsgd@l
244    VK_PPC_GOT_TLSGD_HI,   // symbol@got@tlsgd@h
245    VK_PPC_GOT_TLSGD_HA,   // symbol@got@tlsgd@ha
246    VK_PPC_TLSGD,          // symbol@tlsgd
247    VK_PPC_GOT_TLSLD,      // symbol@got@tlsld
248    VK_PPC_GOT_TLSLD_LO,   // symbol@got@tlsld@l
249    VK_PPC_GOT_TLSLD_HI,   // symbol@got@tlsld@h
250    VK_PPC_GOT_TLSLD_HA,   // symbol@got@tlsld@ha
251    VK_PPC_TLSLD,          // symbol@tlsld
252    VK_PPC_LOCAL,          // symbol@local
253
254    VK_COFF_IMGREL32, // symbol@imgrel (image-relative)
255
256    VK_Hexagon_PCREL,
257    VK_Hexagon_LO16,
258    VK_Hexagon_HI16,
259    VK_Hexagon_GPREL,
260    VK_Hexagon_GD_GOT,
261    VK_Hexagon_LD_GOT,
262    VK_Hexagon_GD_PLT,
263    VK_Hexagon_LD_PLT,
264    VK_Hexagon_IE,
265    VK_Hexagon_IE_GOT,
266
267    VK_WebAssembly_FUNCTION, // Function table index, rather than virtual addr
268
269    VK_TPREL,
270    VK_DTPREL
271  };
272
273private:
274  /// The symbol reference modifier.
275  const VariantKind Kind;
276
277  /// Specifies how the variant kind should be printed.
278  const unsigned UseParensForSymbolVariant : 1;
279
280  // FIXME: Remove this bit.
281  const unsigned HasSubsectionsViaSymbols : 1;
282
283  /// The symbol being referenced.
284  const MCSymbol *Symbol;
285
286  explicit MCSymbolRefExpr(const MCSymbol *Symbol, VariantKind Kind,
287                           const MCAsmInfo *MAI);
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
308  VariantKind getKind() const { return Kind; }
309
310  void printVariantKind(raw_ostream &OS) const;
311
312  bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
313
314  /// @}
315  /// \name Static Utility Functions
316  /// @{
317
318  static StringRef getVariantKindName(VariantKind Kind);
319
320  static VariantKind getVariantKindForName(StringRef Name);
321
322  /// @}
323
324  static bool classof(const MCExpr *E) {
325    return E->getKind() == MCExpr::SymbolRef;
326  }
327};
328
329/// \brief Unary assembler expressions.
330class MCUnaryExpr : public MCExpr {
331public:
332  enum Opcode {
333    LNot,  ///< Logical negation.
334    Minus, ///< Unary minus.
335    Not,   ///< Bitwise negation.
336    Plus   ///< Unary plus.
337  };
338
339private:
340  Opcode Op;
341  const MCExpr *Expr;
342
343  MCUnaryExpr(Opcode Op, const MCExpr *Expr)
344      : MCExpr(MCExpr::Unary), Op(Op), Expr(Expr) {}
345
346public:
347  /// \name Construction
348  /// @{
349
350  static const MCUnaryExpr *create(Opcode Op, const MCExpr *Expr,
351                                   MCContext &Ctx);
352  static const MCUnaryExpr *createLNot(const MCExpr *Expr, MCContext &Ctx) {
353    return create(LNot, Expr, Ctx);
354  }
355  static const MCUnaryExpr *createMinus(const MCExpr *Expr, MCContext &Ctx) {
356    return create(Minus, Expr, Ctx);
357  }
358  static const MCUnaryExpr *createNot(const MCExpr *Expr, MCContext &Ctx) {
359    return create(Not, Expr, Ctx);
360  }
361  static const MCUnaryExpr *createPlus(const MCExpr *Expr, MCContext &Ctx) {
362    return create(Plus, Expr, Ctx);
363  }
364
365  /// @}
366  /// \name Accessors
367  /// @{
368
369  /// \brief Get the kind of this unary expression.
370  Opcode getOpcode() const { return Op; }
371
372  /// \brief Get the child of this unary expression.
373  const MCExpr *getSubExpr() const { return Expr; }
374
375  /// @}
376
377  static bool classof(const MCExpr *E) {
378    return E->getKind() == MCExpr::Unary;
379  }
380};
381
382/// \brief Binary assembler expressions.
383class MCBinaryExpr : public MCExpr {
384public:
385  enum Opcode {
386    Add,  ///< Addition.
387    And,  ///< Bitwise and.
388    Div,  ///< Signed division.
389    EQ,   ///< Equality comparison.
390    GT,   ///< Signed greater than comparison (result is either 0 or some
391          ///< target-specific non-zero value)
392    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
393          ///< some target-specific non-zero value).
394    LAnd, ///< Logical and.
395    LOr,  ///< Logical or.
396    LT,   ///< Signed less than comparison (result is either 0 or
397          ///< some target-specific non-zero value).
398    LTE,  ///< Signed less than or equal comparison (result is either 0 or
399          ///< some target-specific non-zero value).
400    Mod,  ///< Signed remainder.
401    Mul,  ///< Multiplication.
402    NE,   ///< Inequality comparison.
403    Or,   ///< Bitwise or.
404    Shl,  ///< Shift left.
405    AShr, ///< Arithmetic shift right.
406    LShr, ///< Logical shift right.
407    Sub,  ///< Subtraction.
408    Xor   ///< Bitwise exclusive or.
409  };
410
411private:
412  Opcode Op;
413  const MCExpr *LHS, *RHS;
414
415  MCBinaryExpr(Opcode Op, const MCExpr *LHS, const MCExpr *RHS)
416      : MCExpr(MCExpr::Binary), Op(Op), LHS(LHS), RHS(RHS) {}
417
418public:
419  /// \name Construction
420  /// @{
421
422  static const MCBinaryExpr *create(Opcode Op, const MCExpr *LHS,
423                                    const MCExpr *RHS, MCContext &Ctx);
424  static const MCBinaryExpr *createAdd(const MCExpr *LHS, const MCExpr *RHS,
425                                       MCContext &Ctx) {
426    return create(Add, LHS, RHS, Ctx);
427  }
428  static const MCBinaryExpr *createAnd(const MCExpr *LHS, const MCExpr *RHS,
429                                       MCContext &Ctx) {
430    return create(And, LHS, RHS, Ctx);
431  }
432  static const MCBinaryExpr *createDiv(const MCExpr *LHS, const MCExpr *RHS,
433                                       MCContext &Ctx) {
434    return create(Div, LHS, RHS, Ctx);
435  }
436  static const MCBinaryExpr *createEQ(const MCExpr *LHS, const MCExpr *RHS,
437                                      MCContext &Ctx) {
438    return create(EQ, LHS, RHS, Ctx);
439  }
440  static const MCBinaryExpr *createGT(const MCExpr *LHS, const MCExpr *RHS,
441                                      MCContext &Ctx) {
442    return create(GT, LHS, RHS, Ctx);
443  }
444  static const MCBinaryExpr *createGTE(const MCExpr *LHS, const MCExpr *RHS,
445                                       MCContext &Ctx) {
446    return create(GTE, LHS, RHS, Ctx);
447  }
448  static const MCBinaryExpr *createLAnd(const MCExpr *LHS, const MCExpr *RHS,
449                                        MCContext &Ctx) {
450    return create(LAnd, LHS, RHS, Ctx);
451  }
452  static const MCBinaryExpr *createLOr(const MCExpr *LHS, const MCExpr *RHS,
453                                       MCContext &Ctx) {
454    return create(LOr, LHS, RHS, Ctx);
455  }
456  static const MCBinaryExpr *createLT(const MCExpr *LHS, const MCExpr *RHS,
457                                      MCContext &Ctx) {
458    return create(LT, LHS, RHS, Ctx);
459  }
460  static const MCBinaryExpr *createLTE(const MCExpr *LHS, const MCExpr *RHS,
461                                       MCContext &Ctx) {
462    return create(LTE, LHS, RHS, Ctx);
463  }
464  static const MCBinaryExpr *createMod(const MCExpr *LHS, const MCExpr *RHS,
465                                       MCContext &Ctx) {
466    return create(Mod, LHS, RHS, Ctx);
467  }
468  static const MCBinaryExpr *createMul(const MCExpr *LHS, const MCExpr *RHS,
469                                       MCContext &Ctx) {
470    return create(Mul, LHS, RHS, Ctx);
471  }
472  static const MCBinaryExpr *createNE(const MCExpr *LHS, const MCExpr *RHS,
473                                      MCContext &Ctx) {
474    return create(NE, LHS, RHS, Ctx);
475  }
476  static const MCBinaryExpr *createOr(const MCExpr *LHS, const MCExpr *RHS,
477                                      MCContext &Ctx) {
478    return create(Or, LHS, RHS, Ctx);
479  }
480  static const MCBinaryExpr *createShl(const MCExpr *LHS, const MCExpr *RHS,
481                                       MCContext &Ctx) {
482    return create(Shl, LHS, RHS, Ctx);
483  }
484  static const MCBinaryExpr *createAShr(const MCExpr *LHS, const MCExpr *RHS,
485                                       MCContext &Ctx) {
486    return create(AShr, LHS, RHS, Ctx);
487  }
488  static const MCBinaryExpr *createLShr(const MCExpr *LHS, const MCExpr *RHS,
489                                       MCContext &Ctx) {
490    return create(LShr, LHS, RHS, Ctx);
491  }
492  static const MCBinaryExpr *createSub(const MCExpr *LHS, const MCExpr *RHS,
493                                       MCContext &Ctx) {
494    return create(Sub, LHS, RHS, Ctx);
495  }
496  static const MCBinaryExpr *createXor(const MCExpr *LHS, const MCExpr *RHS,
497                                       MCContext &Ctx) {
498    return create(Xor, LHS, RHS, Ctx);
499  }
500
501  /// @}
502  /// \name Accessors
503  /// @{
504
505  /// \brief Get the kind of this binary expression.
506  Opcode getOpcode() const { return Op; }
507
508  /// \brief Get the left-hand side expression of the binary operator.
509  const MCExpr *getLHS() const { return LHS; }
510
511  /// \brief Get the right-hand side expression of the binary operator.
512  const MCExpr *getRHS() const { return RHS; }
513
514  /// @}
515
516  static bool classof(const MCExpr *E) {
517    return E->getKind() == MCExpr::Binary;
518  }
519};
520
521/// \brief This is an extension point for target-specific MCExpr subclasses to
522/// implement.
523///
524/// NOTE: All subclasses are required to have trivial destructors because
525/// MCExprs are bump pointer allocated and not destructed.
526class MCTargetExpr : public MCExpr {
527  virtual void anchor();
528protected:
529  MCTargetExpr() : MCExpr(Target) {}
530  virtual ~MCTargetExpr() {}
531public:
532  virtual void printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const = 0;
533  virtual bool evaluateAsRelocatableImpl(MCValue &Res,
534                                         const MCAsmLayout *Layout,
535                                         const MCFixup *Fixup) const = 0;
536  virtual void visitUsedExpr(MCStreamer& Streamer) const = 0;
537  virtual MCFragment *findAssociatedFragment() const = 0;
538
539  virtual void fixELFSymbolsInTLSFixups(MCAssembler &) const = 0;
540
541  static bool classof(const MCExpr *E) {
542    return E->getKind() == MCExpr::Target;
543  }
544};
545
546} // end namespace llvm
547
548#endif
549