MCExpr.h revision a1000742d28f33dd8dd9858e64282e7749c0bd64 
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
180private:
181  /// The symbol being referenced.
182  const MCSymbol *Symbol;
183
184  /// The symbol reference modifier.
185  const VariantKind Kind;
186
187  explicit MCSymbolRefExpr(const MCSymbol *_Symbol, VariantKind _Kind)
188    : MCExpr(MCExpr::SymbolRef), Symbol(_Symbol), Kind(_Kind) {}
189
190public:
191  /// @name Construction
192  /// @{
193
194  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, MCContext &Ctx) {
195    return MCSymbolRefExpr::Create(Symbol, VK_None, Ctx);
196  }
197
198  static const MCSymbolRefExpr *Create(const MCSymbol *Symbol, VariantKind Kind,
199                                       MCContext &Ctx);
200  static const MCSymbolRefExpr *Create(StringRef Name, VariantKind Kind,
201                                       MCContext &Ctx);
202
203  /// @}
204  /// @name Accessors
205  /// @{
206
207  const MCSymbol &getSymbol() const { return *Symbol; }
208
209  VariantKind getKind() const { return Kind; }
210
211  /// @}
212  /// @name Static Utility Functions
213  /// @{
214
215  static StringRef getVariantKindName(VariantKind Kind);
216
217  static VariantKind getVariantKindForName(StringRef Name);
218
219  /// @}
220
221  static bool classof(const MCExpr *E) {
222    return E->getKind() == MCExpr::SymbolRef;
223  }
224  static bool classof(const MCSymbolRefExpr *) { return true; }
225};
226
227/// MCUnaryExpr - Unary assembler expressions.
228class MCUnaryExpr : public MCExpr {
229public:
230  enum Opcode {
231    LNot,  ///< Logical negation.
232    Minus, ///< Unary minus.
233    Not,   ///< Bitwise negation.
234    Plus   ///< Unary plus.
235  };
236
237private:
238  Opcode Op;
239  const MCExpr *Expr;
240
241  MCUnaryExpr(Opcode _Op, const MCExpr *_Expr)
242    : MCExpr(MCExpr::Unary), Op(_Op), Expr(_Expr) {}
243
244public:
245  /// @name Construction
246  /// @{
247
248  static const MCUnaryExpr *Create(Opcode Op, const MCExpr *Expr,
249                                   MCContext &Ctx);
250  static const MCUnaryExpr *CreateLNot(const MCExpr *Expr, MCContext &Ctx) {
251    return Create(LNot, Expr, Ctx);
252  }
253  static const MCUnaryExpr *CreateMinus(const MCExpr *Expr, MCContext &Ctx) {
254    return Create(Minus, Expr, Ctx);
255  }
256  static const MCUnaryExpr *CreateNot(const MCExpr *Expr, MCContext &Ctx) {
257    return Create(Not, Expr, Ctx);
258  }
259  static const MCUnaryExpr *CreatePlus(const MCExpr *Expr, MCContext &Ctx) {
260    return Create(Plus, Expr, Ctx);
261  }
262
263  /// @}
264  /// @name Accessors
265  /// @{
266
267  /// getOpcode - Get the kind of this unary expression.
268  Opcode getOpcode() const { return Op; }
269
270  /// getSubExpr - Get the child of this unary expression.
271  const MCExpr *getSubExpr() const { return Expr; }
272
273  /// @}
274
275  static bool classof(const MCExpr *E) {
276    return E->getKind() == MCExpr::Unary;
277  }
278  static bool classof(const MCUnaryExpr *) { return true; }
279};
280
281/// MCBinaryExpr - Binary assembler expressions.
282class MCBinaryExpr : public MCExpr {
283public:
284  enum Opcode {
285    Add,  ///< Addition.
286    And,  ///< Bitwise and.
287    Div,  ///< Signed division.
288    EQ,   ///< Equality comparison.
289    GT,   ///< Signed greater than comparison (result is either 0 or some
290          ///< target-specific non-zero value)
291    GTE,  ///< Signed greater than or equal comparison (result is either 0 or
292          ///< some target-specific non-zero value).
293    LAnd, ///< Logical and.
294    LOr,  ///< Logical or.
295    LT,   ///< Signed less than comparison (result is either 0 or
296          ///< some target-specific non-zero value).
297    LTE,  ///< Signed less than or equal comparison (result is either 0 or
298          ///< some target-specific non-zero value).
299    Mod,  ///< Signed remainder.
300    Mul,  ///< Multiplication.
301    NE,   ///< Inequality comparison.
302    Or,   ///< Bitwise or.
303    Shl,  ///< Shift left.
304    Shr,  ///< Shift right (arithmetic or logical, depending on target)
305    Sub,  ///< Subtraction.
306    Xor   ///< Bitwise exclusive or.
307  };
308
309private:
310  Opcode Op;
311  const MCExpr *LHS, *RHS;
312
313  MCBinaryExpr(Opcode _Op, const MCExpr *_LHS, const MCExpr *_RHS)
314    : MCExpr(MCExpr::Binary), Op(_Op), LHS(_LHS), RHS(_RHS) {}
315
316public:
317  /// @name Construction
318  /// @{
319
320  static const MCBinaryExpr *Create(Opcode Op, const MCExpr *LHS,
321                                    const MCExpr *RHS, MCContext &Ctx);
322  static const MCBinaryExpr *CreateAdd(const MCExpr *LHS, const MCExpr *RHS,
323                                       MCContext &Ctx) {
324    return Create(Add, LHS, RHS, Ctx);
325  }
326  static const MCBinaryExpr *CreateAnd(const MCExpr *LHS, const MCExpr *RHS,
327                                       MCContext &Ctx) {
328    return Create(And, LHS, RHS, Ctx);
329  }
330  static const MCBinaryExpr *CreateDiv(const MCExpr *LHS, const MCExpr *RHS,
331                                       MCContext &Ctx) {
332    return Create(Div, LHS, RHS, Ctx);
333  }
334  static const MCBinaryExpr *CreateEQ(const MCExpr *LHS, const MCExpr *RHS,
335                                      MCContext &Ctx) {
336    return Create(EQ, LHS, RHS, Ctx);
337  }
338  static const MCBinaryExpr *CreateGT(const MCExpr *LHS, const MCExpr *RHS,
339                                      MCContext &Ctx) {
340    return Create(GT, LHS, RHS, Ctx);
341  }
342  static const MCBinaryExpr *CreateGTE(const MCExpr *LHS, const MCExpr *RHS,
343                                       MCContext &Ctx) {
344    return Create(GTE, LHS, RHS, Ctx);
345  }
346  static const MCBinaryExpr *CreateLAnd(const MCExpr *LHS, const MCExpr *RHS,
347                                        MCContext &Ctx) {
348    return Create(LAnd, LHS, RHS, Ctx);
349  }
350  static const MCBinaryExpr *CreateLOr(const MCExpr *LHS, const MCExpr *RHS,
351                                       MCContext &Ctx) {
352    return Create(LOr, LHS, RHS, Ctx);
353  }
354  static const MCBinaryExpr *CreateLT(const MCExpr *LHS, const MCExpr *RHS,
355                                      MCContext &Ctx) {
356    return Create(LT, LHS, RHS, Ctx);
357  }
358  static const MCBinaryExpr *CreateLTE(const MCExpr *LHS, const MCExpr *RHS,
359                                       MCContext &Ctx) {
360    return Create(LTE, LHS, RHS, Ctx);
361  }
362  static const MCBinaryExpr *CreateMod(const MCExpr *LHS, const MCExpr *RHS,
363                                       MCContext &Ctx) {
364    return Create(Mod, LHS, RHS, Ctx);
365  }
366  static const MCBinaryExpr *CreateMul(const MCExpr *LHS, const MCExpr *RHS,
367                                       MCContext &Ctx) {
368    return Create(Mul, LHS, RHS, Ctx);
369  }
370  static const MCBinaryExpr *CreateNE(const MCExpr *LHS, const MCExpr *RHS,
371                                      MCContext &Ctx) {
372    return Create(NE, LHS, RHS, Ctx);
373  }
374  static const MCBinaryExpr *CreateOr(const MCExpr *LHS, const MCExpr *RHS,
375                                      MCContext &Ctx) {
376    return Create(Or, LHS, RHS, Ctx);
377  }
378  static const MCBinaryExpr *CreateShl(const MCExpr *LHS, const MCExpr *RHS,
379                                       MCContext &Ctx) {
380    return Create(Shl, LHS, RHS, Ctx);
381  }
382  static const MCBinaryExpr *CreateShr(const MCExpr *LHS, const MCExpr *RHS,
383                                       MCContext &Ctx) {
384    return Create(Shr, LHS, RHS, Ctx);
385  }
386  static const MCBinaryExpr *CreateSub(const MCExpr *LHS, const MCExpr *RHS,
387                                       MCContext &Ctx) {
388    return Create(Sub, LHS, RHS, Ctx);
389  }
390  static const MCBinaryExpr *CreateXor(const MCExpr *LHS, const MCExpr *RHS,
391                                       MCContext &Ctx) {
392    return Create(Xor, LHS, RHS, Ctx);
393  }
394
395  /// @}
396  /// @name Accessors
397  /// @{
398
399  /// getOpcode - Get the kind of this binary expression.
400  Opcode getOpcode() const { return Op; }
401
402  /// getLHS - Get the left-hand side expression of the binary operator.
403  const MCExpr *getLHS() const { return LHS; }
404
405  /// getRHS - Get the right-hand side expression of the binary operator.
406  const MCExpr *getRHS() const { return RHS; }
407
408  /// @}
409
410  static bool classof(const MCExpr *E) {
411    return E->getKind() == MCExpr::Binary;
412  }
413  static bool classof(const MCBinaryExpr *) { return true; }
414};
415
416/// MCTargetExpr - This is an extension point for target-specific MCExpr
417/// subclasses to implement.
418///
419/// NOTE: All subclasses are required to have trivial destructors because
420/// MCExprs are bump pointer allocated and not destructed.
421class MCTargetExpr : public MCExpr {
422  virtual void Anchor();
423protected:
424  MCTargetExpr() : MCExpr(Target) {}
425  virtual ~MCTargetExpr() {}
426public:
427
428  virtual void PrintImpl(raw_ostream &OS) const = 0;
429  virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
430                                         const MCAsmLayout *Layout) const = 0;
431  virtual void AddValueSymbols(MCAssembler *) const = 0;
432  virtual const MCSection *FindAssociatedSection() const = 0;
433
434  static bool classof(const MCExpr *E) {
435    return E->getKind() == MCExpr::Target;
436  }
437  static bool classof(const MCTargetExpr *) { return true; }
438};
439
440} // end namespace llvm
441
442#endif
443