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MCExpr.cpp
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1 //===- MCExpr.cpp - Assembly Level Expression Implementation --------------===//
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 #define DEBUG_TYPE "mcexpr"
11 #include "llvm/MC/MCExpr.h"
12 #include "llvm/ADT/Statistic.h"
13 #include "llvm/ADT/StringSwitch.h"
14 #include "llvm/MC/MCAsmLayout.h"
15 #include "llvm/MC/MCAssembler.h"
16 #include "llvm/MC/MCContext.h"
17 #include "llvm/MC/MCObjectWriter.h"
18 #include "llvm/MC/MCSymbol.h"
19 #include "llvm/MC/MCValue.h"
20 #include "llvm/Support/Debug.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/raw_ostream.h"
23 using namespace llvm;
24 
25 namespace {
26 namespace stats {
27 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
28 }
29 }
30 
31 void MCExpr::print(raw_ostream &OS) const {
32  switch (getKind()) {
33  case MCExpr::Target:
34  return cast<MCTargetExpr>(this)->PrintImpl(OS);
35  case MCExpr::Constant:
36  OS << cast<MCConstantExpr>(*this).getValue();
37  return;
38 
39  case MCExpr::SymbolRef: {
40  const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
41  const MCSymbol &Sym = SRE.getSymbol();
42  // Parenthesize names that start with $ so that they don't look like
43  // absolute names.
44  bool UseParens = Sym.getName()[0] == '$';
45  if (UseParens)
46  OS << '(' << Sym << ')';
47  else
48  OS << Sym;
49 
50  if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_NONE ||
51  SRE.getKind() == MCSymbolRefExpr::VK_ARM_PLT ||
52  SRE.getKind() == MCSymbolRefExpr::VK_ARM_TLSGD ||
53  SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOT ||
54  SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTOFF ||
55  SRE.getKind() == MCSymbolRefExpr::VK_ARM_TPOFF ||
56  SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTTPOFF ||
57  SRE.getKind() == MCSymbolRefExpr::VK_ARM_TARGET1 ||
58  SRE.getKind() == MCSymbolRefExpr::VK_ARM_TARGET2 ||
59  SRE.getKind() == MCSymbolRefExpr::VK_ARM_PREL31)
60  OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
61  else if (SRE.getKind() != MCSymbolRefExpr::VK_None)
62  OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
63 
64  return;
65  }
66 
67  case MCExpr::Unary: {
68  const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
69  switch (UE.getOpcode()) {
70  case MCUnaryExpr::LNot: OS << '!'; break;
71  case MCUnaryExpr::Minus: OS << '-'; break;
72  case MCUnaryExpr::Not: OS << '~'; break;
73  case MCUnaryExpr::Plus: OS << '+'; break;
74  }
75  OS << *UE.getSubExpr();
76  return;
77  }
78 
79  case MCExpr::Binary: {
80  const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
81 
82  // Only print parens around the LHS if it is non-trivial.
83  if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
84  OS << *BE.getLHS();
85  } else {
86  OS << '(' << *BE.getLHS() << ')';
87  }
88 
89  switch (BE.getOpcode()) {
90  case MCBinaryExpr::Add:
91  // Print "X-42" instead of "X+-42".
92  if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
93  if (RHSC->getValue() < 0) {
94  OS << RHSC->getValue();
95  return;
96  }
97  }
98 
99  OS << '+';
100  break;
101  case MCBinaryExpr::And: OS << '&'; break;
102  case MCBinaryExpr::Div: OS << '/'; break;
103  case MCBinaryExpr::EQ: OS << "=="; break;
104  case MCBinaryExpr::GT: OS << '>'; break;
105  case MCBinaryExpr::GTE: OS << ">="; break;
106  case MCBinaryExpr::LAnd: OS << "&&"; break;
107  case MCBinaryExpr::LOr: OS << "||"; break;
108  case MCBinaryExpr::LT: OS << '<'; break;
109  case MCBinaryExpr::LTE: OS << "<="; break;
110  case MCBinaryExpr::Mod: OS << '%'; break;
111  case MCBinaryExpr::Mul: OS << '*'; break;
112  case MCBinaryExpr::NE: OS << "!="; break;
113  case MCBinaryExpr::Or: OS << '|'; break;
114  case MCBinaryExpr::Shl: OS << "<<"; break;
115  case MCBinaryExpr::Shr: OS << ">>"; break;
116  case MCBinaryExpr::Sub: OS << '-'; break;
117  case MCBinaryExpr::Xor: OS << '^'; break;
118  }
119 
120  // Only print parens around the LHS if it is non-trivial.
121  if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
122  OS << *BE.getRHS();
123  } else {
124  OS << '(' << *BE.getRHS() << ')';
125  }
126  return;
127  }
128  }
129 
130  llvm_unreachable("Invalid expression kind!");
131 }
132 
133 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
134 void MCExpr::dump() const {
135  print(dbgs());
136  dbgs() << '\n';
137 }
138 #endif
139 
140 /* *** */
141 
142 const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS,
143  const MCExpr *RHS, MCContext &Ctx) {
144  return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
145 }
146 
147 const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr,
148  MCContext &Ctx) {
149  return new (Ctx) MCUnaryExpr(Opc, Expr);
150 }
151 
152 const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) {
153  return new (Ctx) MCConstantExpr(Value);
154 }
155 
156 /* *** */
157 
158 const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
159  VariantKind Kind,
160  MCContext &Ctx) {
161  return new (Ctx) MCSymbolRefExpr(Sym, Kind);
162 }
163 
164 const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind,
165  MCContext &Ctx) {
166  return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx);
167 }
168 
169 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
170  switch (Kind) {
171  case VK_Invalid: return "<<invalid>>";
172  case VK_None: return "<<none>>";
173 
174  case VK_GOT: return "GOT";
175  case VK_GOTOFF: return "GOTOFF";
176  case VK_GOTPCREL: return "GOTPCREL";
177  case VK_GOTTPOFF: return "GOTTPOFF";
178  case VK_INDNTPOFF: return "INDNTPOFF";
179  case VK_NTPOFF: return "NTPOFF";
180  case VK_GOTNTPOFF: return "GOTNTPOFF";
181  case VK_PLT: return "PLT";
182  case VK_TLSGD: return "TLSGD";
183  case VK_TLSLD: return "TLSLD";
184  case VK_TLSLDM: return "TLSLDM";
185  case VK_TPOFF: return "TPOFF";
186  case VK_DTPOFF: return "DTPOFF";
187  case VK_TLVP: return "TLVP";
188  case VK_SECREL: return "SECREL32";
189  case VK_ARM_NONE: return "(NONE)";
190  case VK_ARM_PLT: return "(PLT)";
191  case VK_ARM_GOT: return "(GOT)";
192  case VK_ARM_GOTOFF: return "(GOTOFF)";
193  case VK_ARM_TPOFF: return "(tpoff)";
194  case VK_ARM_GOTTPOFF: return "(gottpoff)";
195  case VK_ARM_TLSGD: return "(tlsgd)";
196  case VK_ARM_TARGET1: return "(target1)";
197  case VK_ARM_TARGET2: return "(target2)";
198  case VK_ARM_PREL31: return "(prel31)";
199  case VK_PPC_LO: return "l";
200  case VK_PPC_HI: return "h";
201  case VK_PPC_HA: return "ha";
202  case VK_PPC_HIGHER: return "higher";
203  case VK_PPC_HIGHERA: return "highera";
204  case VK_PPC_HIGHEST: return "highest";
205  case VK_PPC_HIGHESTA: return "highesta";
206  case VK_PPC_GOT_LO: return "got@l";
207  case VK_PPC_GOT_HI: return "got@h";
208  case VK_PPC_GOT_HA: return "got@ha";
209  case VK_PPC_TOCBASE: return "tocbase";
210  case VK_PPC_TOC: return "toc";
211  case VK_PPC_TOC_LO: return "toc@l";
212  case VK_PPC_TOC_HI: return "toc@h";
213  case VK_PPC_TOC_HA: return "toc@ha";
214  case VK_PPC_DTPMOD: return "dtpmod";
215  case VK_PPC_TPREL: return "tprel";
216  case VK_PPC_TPREL_LO: return "tprel@l";
217  case VK_PPC_TPREL_HI: return "tprel@h";
218  case VK_PPC_TPREL_HA: return "tprel@ha";
219  case VK_PPC_TPREL_HIGHER: return "tprel@higher";
220  case VK_PPC_TPREL_HIGHERA: return "tprel@highera";
221  case VK_PPC_TPREL_HIGHEST: return "tprel@highest";
222  case VK_PPC_TPREL_HIGHESTA: return "tprel@highesta";
223  case VK_PPC_DTPREL: return "dtprel";
224  case VK_PPC_DTPREL_LO: return "dtprel@l";
225  case VK_PPC_DTPREL_HI: return "dtprel@h";
226  case VK_PPC_DTPREL_HA: return "dtprel@ha";
227  case VK_PPC_DTPREL_HIGHER: return "dtprel@higher";
228  case VK_PPC_DTPREL_HIGHERA: return "dtprel@highera";
229  case VK_PPC_DTPREL_HIGHEST: return "dtprel@highest";
230  case VK_PPC_DTPREL_HIGHESTA: return "dtprel@highesta";
231  case VK_PPC_GOT_TPREL: return "got@tprel";
232  case VK_PPC_GOT_TPREL_LO: return "got@tprel@l";
233  case VK_PPC_GOT_TPREL_HI: return "got@tprel@h";
234  case VK_PPC_GOT_TPREL_HA: return "got@tprel@ha";
235  case VK_PPC_GOT_DTPREL: return "got@dtprel";
236  case VK_PPC_GOT_DTPREL_LO: return "got@dtprel@l";
237  case VK_PPC_GOT_DTPREL_HI: return "got@dtprel@h";
238  case VK_PPC_GOT_DTPREL_HA: return "got@dtprel@ha";
239  case VK_PPC_TLS: return "tls";
240  case VK_PPC_GOT_TLSGD: return "got@tlsgd";
241  case VK_PPC_GOT_TLSGD_LO: return "got@tlsgd@l";
242  case VK_PPC_GOT_TLSGD_HI: return "got@tlsgd@h";
243  case VK_PPC_GOT_TLSGD_HA: return "got@tlsgd@ha";
244  case VK_PPC_TLSGD: return "tlsgd";
245  case VK_PPC_GOT_TLSLD: return "got@tlsld";
246  case VK_PPC_GOT_TLSLD_LO: return "got@tlsld@l";
247  case VK_PPC_GOT_TLSLD_HI: return "got@tlsld@h";
248  case VK_PPC_GOT_TLSLD_HA: return "got@tlsld@ha";
249  case VK_PPC_TLSLD: return "tlsld";
250  case VK_Mips_GPREL: return "GPREL";
251  case VK_Mips_GOT_CALL: return "GOT_CALL";
252  case VK_Mips_GOT16: return "GOT16";
253  case VK_Mips_GOT: return "GOT";
254  case VK_Mips_ABS_HI: return "ABS_HI";
255  case VK_Mips_ABS_LO: return "ABS_LO";
256  case VK_Mips_TLSGD: return "TLSGD";
257  case VK_Mips_TLSLDM: return "TLSLDM";
258  case VK_Mips_DTPREL_HI: return "DTPREL_HI";
259  case VK_Mips_DTPREL_LO: return "DTPREL_LO";
260  case VK_Mips_GOTTPREL: return "GOTTPREL";
261  case VK_Mips_TPREL_HI: return "TPREL_HI";
262  case VK_Mips_TPREL_LO: return "TPREL_LO";
263  case VK_Mips_GPOFF_HI: return "GPOFF_HI";
264  case VK_Mips_GPOFF_LO: return "GPOFF_LO";
265  case VK_Mips_GOT_DISP: return "GOT_DISP";
266  case VK_Mips_GOT_PAGE: return "GOT_PAGE";
267  case VK_Mips_GOT_OFST: return "GOT_OFST";
268  case VK_Mips_HIGHER: return "HIGHER";
269  case VK_Mips_HIGHEST: return "HIGHEST";
270  case VK_Mips_GOT_HI16: return "GOT_HI16";
271  case VK_Mips_GOT_LO16: return "GOT_LO16";
272  case VK_Mips_CALL_HI16: return "CALL_HI16";
273  case VK_Mips_CALL_LO16: return "CALL_LO16";
274  case VK_COFF_IMGREL32: return "IMGREL32";
275  }
276  llvm_unreachable("Invalid variant kind");
277 }
278 
279 MCSymbolRefExpr::VariantKind
280 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
281  return StringSwitch<VariantKind>(Name)
282  .Case("GOT", VK_GOT)
283  .Case("got", VK_GOT)
284  .Case("GOTOFF", VK_GOTOFF)
285  .Case("gotoff", VK_GOTOFF)
286  .Case("GOTPCREL", VK_GOTPCREL)
287  .Case("gotpcrel", VK_GOTPCREL)
288  .Case("GOTTPOFF", VK_GOTTPOFF)
289  .Case("gottpoff", VK_GOTTPOFF)
290  .Case("INDNTPOFF", VK_INDNTPOFF)
291  .Case("indntpoff", VK_INDNTPOFF)
292  .Case("NTPOFF", VK_NTPOFF)
293  .Case("ntpoff", VK_NTPOFF)
294  .Case("GOTNTPOFF", VK_GOTNTPOFF)
295  .Case("gotntpoff", VK_GOTNTPOFF)
296  .Case("PLT", VK_PLT)
297  .Case("plt", VK_PLT)
298  .Case("TLSGD", VK_TLSGD)
299  .Case("tlsgd", VK_TLSGD)
300  .Case("TLSLD", VK_TLSLD)
301  .Case("tlsld", VK_TLSLD)
302  .Case("TLSLDM", VK_TLSLDM)
303  .Case("tlsldm", VK_TLSLDM)
304  .Case("TPOFF", VK_TPOFF)
305  .Case("tpoff", VK_TPOFF)
306  .Case("DTPOFF", VK_DTPOFF)
307  .Case("dtpoff", VK_DTPOFF)
308  .Case("TLVP", VK_TLVP)
309  .Case("tlvp", VK_TLVP)
310  .Case("IMGREL", VK_COFF_IMGREL32)
311  .Case("imgrel", VK_COFF_IMGREL32)
312  .Case("SECREL32", VK_SECREL)
313  .Case("secrel32", VK_SECREL)
314  .Case("L", VK_PPC_LO)
315  .Case("l", VK_PPC_LO)
316  .Case("H", VK_PPC_HI)
317  .Case("h", VK_PPC_HI)
318  .Case("HA", VK_PPC_HA)
319  .Case("ha", VK_PPC_HA)
320  .Case("HIGHER", VK_PPC_HIGHER)
321  .Case("higher", VK_PPC_HIGHER)
322  .Case("HIGHERA", VK_PPC_HIGHERA)
323  .Case("highera", VK_PPC_HIGHERA)
324  .Case("HIGHEST", VK_PPC_HIGHEST)
325  .Case("highest", VK_PPC_HIGHEST)
326  .Case("HIGHESTA", VK_PPC_HIGHESTA)
327  .Case("highesta", VK_PPC_HIGHESTA)
328  .Case("GOT@L", VK_PPC_GOT_LO)
329  .Case("got@l", VK_PPC_GOT_LO)
330  .Case("GOT@H", VK_PPC_GOT_HI)
331  .Case("got@h", VK_PPC_GOT_HI)
332  .Case("GOT@HA", VK_PPC_GOT_HA)
333  .Case("got@ha", VK_PPC_GOT_HA)
334  .Case("TOCBASE", VK_PPC_TOCBASE)
335  .Case("tocbase", VK_PPC_TOCBASE)
336  .Case("TOC", VK_PPC_TOC)
337  .Case("toc", VK_PPC_TOC)
338  .Case("TOC@L", VK_PPC_TOC_LO)
339  .Case("toc@l", VK_PPC_TOC_LO)
340  .Case("TOC@H", VK_PPC_TOC_HI)
341  .Case("toc@h", VK_PPC_TOC_HI)
342  .Case("TOC@HA", VK_PPC_TOC_HA)
343  .Case("toc@ha", VK_PPC_TOC_HA)
344  .Case("TLS", VK_PPC_TLS)
345  .Case("tls", VK_PPC_TLS)
346  .Case("DTPMOD", VK_PPC_DTPMOD)
347  .Case("dtpmod", VK_PPC_DTPMOD)
348  .Case("TPREL", VK_PPC_TPREL)
349  .Case("tprel", VK_PPC_TPREL)
350  .Case("TPREL@L", VK_PPC_TPREL_LO)
351  .Case("tprel@l", VK_PPC_TPREL_LO)
352  .Case("TPREL@H", VK_PPC_TPREL_HI)
353  .Case("tprel@h", VK_PPC_TPREL_HI)
354  .Case("TPREL@HA", VK_PPC_TPREL_HA)
355  .Case("tprel@ha", VK_PPC_TPREL_HA)
356  .Case("TPREL@HIGHER", VK_PPC_TPREL_HIGHER)
357  .Case("tprel@higher", VK_PPC_TPREL_HIGHER)
358  .Case("TPREL@HIGHERA", VK_PPC_TPREL_HIGHERA)
359  .Case("tprel@highera", VK_PPC_TPREL_HIGHERA)
360  .Case("TPREL@HIGHEST", VK_PPC_TPREL_HIGHEST)
361  .Case("tprel@highest", VK_PPC_TPREL_HIGHEST)
362  .Case("TPREL@HIGHESTA", VK_PPC_TPREL_HIGHESTA)
363  .Case("tprel@highesta", VK_PPC_TPREL_HIGHESTA)
364  .Case("DTPREL", VK_PPC_DTPREL)
365  .Case("dtprel", VK_PPC_DTPREL)
366  .Case("DTPREL@L", VK_PPC_DTPREL_LO)
367  .Case("dtprel@l", VK_PPC_DTPREL_LO)
368  .Case("DTPREL@H", VK_PPC_DTPREL_HI)
369  .Case("dtprel@h", VK_PPC_DTPREL_HI)
370  .Case("DTPREL@HA", VK_PPC_DTPREL_HA)
371  .Case("dtprel@ha", VK_PPC_DTPREL_HA)
372  .Case("DTPREL@HIGHER", VK_PPC_DTPREL_HIGHER)
373  .Case("dtprel@higher", VK_PPC_DTPREL_HIGHER)
374  .Case("DTPREL@HIGHERA", VK_PPC_DTPREL_HIGHERA)
375  .Case("dtprel@highera", VK_PPC_DTPREL_HIGHERA)
376  .Case("DTPREL@HIGHEST", VK_PPC_DTPREL_HIGHEST)
377  .Case("dtprel@highest", VK_PPC_DTPREL_HIGHEST)
378  .Case("DTPREL@HIGHESTA", VK_PPC_DTPREL_HIGHESTA)
379  .Case("dtprel@highesta", VK_PPC_DTPREL_HIGHESTA)
380  .Case("GOT@TPREL", VK_PPC_GOT_TPREL)
381  .Case("got@tprel", VK_PPC_GOT_TPREL)
382  .Case("GOT@TPREL@L", VK_PPC_GOT_TPREL_LO)
383  .Case("got@tprel@l", VK_PPC_GOT_TPREL_LO)
384  .Case("GOT@TPREL@H", VK_PPC_GOT_TPREL_HI)
385  .Case("got@tprel@h", VK_PPC_GOT_TPREL_HI)
386  .Case("GOT@TPREL@HA", VK_PPC_GOT_TPREL_HA)
387  .Case("got@tprel@ha", VK_PPC_GOT_TPREL_HA)
388  .Case("GOT@DTPREL", VK_PPC_GOT_DTPREL)
389  .Case("got@dtprel", VK_PPC_GOT_DTPREL)
390  .Case("GOT@DTPREL@L", VK_PPC_GOT_DTPREL_LO)
391  .Case("got@dtprel@l", VK_PPC_GOT_DTPREL_LO)
392  .Case("GOT@DTPREL@H", VK_PPC_GOT_DTPREL_HI)
393  .Case("got@dtprel@h", VK_PPC_GOT_DTPREL_HI)
394  .Case("GOT@DTPREL@HA", VK_PPC_GOT_DTPREL_HA)
395  .Case("got@dtprel@ha", VK_PPC_GOT_DTPREL_HA)
396  .Case("GOT@TLSGD", VK_PPC_GOT_TLSGD)
397  .Case("got@tlsgd", VK_PPC_GOT_TLSGD)
398  .Case("GOT@TLSGD@L", VK_PPC_GOT_TLSGD_LO)
399  .Case("got@tlsgd@l", VK_PPC_GOT_TLSGD_LO)
400  .Case("GOT@TLSGD@H", VK_PPC_GOT_TLSGD_HI)
401  .Case("got@tlsgd@h", VK_PPC_GOT_TLSGD_HI)
402  .Case("GOT@TLSGD@HA", VK_PPC_GOT_TLSGD_HA)
403  .Case("got@tlsgd@ha", VK_PPC_GOT_TLSGD_HA)
404  .Case("GOT@TLSLD", VK_PPC_GOT_TLSLD)
405  .Case("got@tlsld", VK_PPC_GOT_TLSLD)
406  .Case("GOT@TLSLD@L", VK_PPC_GOT_TLSLD_LO)
407  .Case("got@tlsld@l", VK_PPC_GOT_TLSLD_LO)
408  .Case("GOT@TLSLD@H", VK_PPC_GOT_TLSLD_HI)
409  .Case("got@tlsld@h", VK_PPC_GOT_TLSLD_HI)
410  .Case("GOT@TLSLD@HA", VK_PPC_GOT_TLSLD_HA)
411  .Case("got@tlsld@ha", VK_PPC_GOT_TLSLD_HA)
412  .Default(VK_Invalid);
413 }
414 
415 /* *** */
416 
417 void MCTargetExpr::anchor() {}
418 
419 /* *** */
420 
421 bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const {
422  return EvaluateAsAbsolute(Res, 0, 0, 0);
423 }
424 
425 bool MCExpr::EvaluateAsAbsolute(int64_t &Res,
426  const MCAsmLayout &Layout) const {
427  return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, 0);
428 }
429 
430 bool MCExpr::EvaluateAsAbsolute(int64_t &Res,
431  const MCAsmLayout &Layout,
432  const SectionAddrMap &Addrs) const {
433  return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs);
434 }
435 
436 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
437  return EvaluateAsAbsolute(Res, &Asm, 0, 0);
438 }
439 
440 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
441  const MCAsmLayout *Layout,
442  const SectionAddrMap *Addrs) const {
443  MCValue Value;
444 
445  // Fast path constants.
446  if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
447  Res = CE->getValue();
448  return true;
449  }
450 
451  // FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us
452  // absolutize differences across sections and that is what the MachO writer
453  // uses Addrs for.
454  bool IsRelocatable =
455  EvaluateAsRelocatableImpl(Value, Asm, Layout, Addrs, /*InSet*/ Addrs);
456 
457  // Record the current value.
458  Res = Value.getConstant();
459 
460  return IsRelocatable && Value.isAbsolute();
461 }
462 
463 /// \brief Helper method for \see EvaluateSymbolAdd().
464 static void AttemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
465  const MCAsmLayout *Layout,
466  const SectionAddrMap *Addrs,
467  bool InSet,
468  const MCSymbolRefExpr *&A,
469  const MCSymbolRefExpr *&B,
470  int64_t &Addend) {
471  if (!A || !B)
472  return;
473 
474  const MCSymbol &SA = A->getSymbol();
475  const MCSymbol &SB = B->getSymbol();
476 
477  if (SA.isUndefined() || SB.isUndefined())
478  return;
479 
480  if (!Asm->getWriter().IsSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
481  return;
482 
483  MCSymbolData &AD = Asm->getSymbolData(SA);
484  MCSymbolData &BD = Asm->getSymbolData(SB);
485 
486  if (AD.getFragment() == BD.getFragment()) {
487  Addend += (AD.getOffset() - BD.getOffset());
488 
489  // Pointers to Thumb symbols need to have their low-bit set to allow
490  // for interworking.
491  if (Asm->isThumbFunc(&SA))
492  Addend |= 1;
493 
494  // Clear the symbol expr pointers to indicate we have folded these
495  // operands.
496  A = B = 0;
497  return;
498  }
499 
500  if (!Layout)
501  return;
502 
503  const MCSectionData &SecA = *AD.getFragment()->getParent();
504  const MCSectionData &SecB = *BD.getFragment()->getParent();
505 
506  if ((&SecA != &SecB) && !Addrs)
507  return;
508 
509  // Eagerly evaluate.
510  Addend += (Layout->getSymbolOffset(&Asm->getSymbolData(A->getSymbol())) -
511  Layout->getSymbolOffset(&Asm->getSymbolData(B->getSymbol())));
512  if (Addrs && (&SecA != &SecB))
513  Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
514 
515  // Pointers to Thumb symbols need to have their low-bit set to allow
516  // for interworking.
517  if (Asm->isThumbFunc(&SA))
518  Addend |= 1;
519 
520  // Clear the symbol expr pointers to indicate we have folded these
521  // operands.
522  A = B = 0;
523 }
524 
525 /// \brief Evaluate the result of an add between (conceptually) two MCValues.
526 ///
527 /// This routine conceptually attempts to construct an MCValue:
528 /// Result = (Result_A - Result_B + Result_Cst)
529 /// from two MCValue's LHS and RHS where
530 /// Result = LHS + RHS
531 /// and
532 /// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
533 ///
534 /// This routine attempts to aggresively fold the operands such that the result
535 /// is representable in an MCValue, but may not always succeed.
536 ///
537 /// \returns True on success, false if the result is not representable in an
538 /// MCValue.
539 
540 /// NOTE: It is really important to have both the Asm and Layout arguments.
541 /// They might look redundant, but this function can be used before layout
542 /// is done (see the object streamer for example) and having the Asm argument
543 /// lets us avoid relaxations early.
544 static bool EvaluateSymbolicAdd(const MCAssembler *Asm,
545  const MCAsmLayout *Layout,
546  const SectionAddrMap *Addrs,
547  bool InSet,
548  const MCValue &LHS,const MCSymbolRefExpr *RHS_A,
549  const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst,
550  MCValue &Res) {
551  // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy
552  // about dealing with modifiers. This will ultimately bite us, one day.
553  const MCSymbolRefExpr *LHS_A = LHS.getSymA();
554  const MCSymbolRefExpr *LHS_B = LHS.getSymB();
555  int64_t LHS_Cst = LHS.getConstant();
556 
557  // Fold the result constant immediately.
558  int64_t Result_Cst = LHS_Cst + RHS_Cst;
559 
560  assert((!Layout || Asm) &&
561  "Must have an assembler object if layout is given!");
562 
563  // If we have a layout, we can fold resolved differences.
564  if (Asm) {
565  // First, fold out any differences which are fully resolved. By
566  // reassociating terms in
567  // Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
568  // we have the four possible differences:
569  // (LHS_A - LHS_B),
570  // (LHS_A - RHS_B),
571  // (RHS_A - LHS_B),
572  // (RHS_A - RHS_B).
573  // Since we are attempting to be as aggressive as possible about folding, we
574  // attempt to evaluate each possible alternative.
575  AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
576  Result_Cst);
577  AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
578  Result_Cst);
579  AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
580  Result_Cst);
581  AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
582  Result_Cst);
583  }
584 
585  // We can't represent the addition or subtraction of two symbols.
586  if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
587  return false;
588 
589  // At this point, we have at most one additive symbol and one subtractive
590  // symbol -- find them.
591  const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
592  const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;
593 
594  // If we have a negated symbol, then we must have also have a non-negated
595  // symbol in order to encode the expression.
596  if (B && !A)
597  return false;
598 
599  Res = MCValue::get(A, B, Result_Cst);
600  return true;
601 }
602 
603 bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
604  const MCAsmLayout &Layout) const {
605  return EvaluateAsRelocatableImpl(Res, &Layout.getAssembler(), &Layout,
606  0, false);
607 }
608 
609 bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
610  const MCAssembler *Asm,
611  const MCAsmLayout *Layout,
612  const SectionAddrMap *Addrs,
613  bool InSet) const {
614  ++stats::MCExprEvaluate;
615 
616  switch (getKind()) {
617  case Target:
618  return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
619 
620  case Constant:
621  Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
622  return true;
623 
624  case SymbolRef: {
625  const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
626  const MCSymbol &Sym = SRE->getSymbol();
627 
628  // Evaluate recursively if this is a variable.
629  if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None) {
630  bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Asm,
631  Layout,
632  Addrs,
633  true);
634  // If we failed to simplify this to a constant, let the target
635  // handle it.
636  if (Ret && !Res.getSymA() && !Res.getSymB())
637  return true;
638  }
639 
640  Res = MCValue::get(SRE, 0, 0);
641  return true;
642  }
643 
644  case Unary: {
645  const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
646  MCValue Value;
647 
648  if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Asm, Layout,
649  Addrs, InSet))
650  return false;
651 
652  switch (AUE->getOpcode()) {
653  case MCUnaryExpr::LNot:
654  if (!Value.isAbsolute())
655  return false;
656  Res = MCValue::get(!Value.getConstant());
657  break;
658  case MCUnaryExpr::Minus:
659  /// -(a - b + const) ==> (b - a - const)
660  if (Value.getSymA() && !Value.getSymB())
661  return false;
662  Res = MCValue::get(Value.getSymB(), Value.getSymA(),
663  -Value.getConstant());
664  break;
665  case MCUnaryExpr::Not:
666  if (!Value.isAbsolute())
667  return false;
668  Res = MCValue::get(~Value.getConstant());
669  break;
670  case MCUnaryExpr::Plus:
671  Res = Value;
672  break;
673  }
674 
675  return true;
676  }
677 
678  case Binary: {
679  const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
680  MCValue LHSValue, RHSValue;
681 
682  if (!ABE->getLHS()->EvaluateAsRelocatableImpl(LHSValue, Asm, Layout,
683  Addrs, InSet) ||
684  !ABE->getRHS()->EvaluateAsRelocatableImpl(RHSValue, Asm, Layout,
685  Addrs, InSet))
686  return false;
687 
688  // We only support a few operations on non-constant expressions, handle
689  // those first.
690  if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
691  switch (ABE->getOpcode()) {
692  default:
693  return false;
694  case MCBinaryExpr::Sub:
695  // Negate RHS and add.
696  return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
697  RHSValue.getSymB(), RHSValue.getSymA(),
698  -RHSValue.getConstant(),
699  Res);
700 
701  case MCBinaryExpr::Add:
702  return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
703  RHSValue.getSymA(), RHSValue.getSymB(),
704  RHSValue.getConstant(),
705  Res);
706  }
707  }
708 
709  // FIXME: We need target hooks for the evaluation. It may be limited in
710  // width, and gas defines the result of comparisons and right shifts
711  // differently from Apple as.
712  int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
713  int64_t Result = 0;
714  switch (ABE->getOpcode()) {
715  case MCBinaryExpr::Add: Result = LHS + RHS; break;
716  case MCBinaryExpr::And: Result = LHS & RHS; break;
717  case MCBinaryExpr::Div: Result = LHS / RHS; break;
718  case MCBinaryExpr::EQ: Result = LHS == RHS; break;
719  case MCBinaryExpr::GT: Result = LHS > RHS; break;
720  case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
721  case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
722  case MCBinaryExpr::LOr: Result = LHS || RHS; break;
723  case MCBinaryExpr::LT: Result = LHS < RHS; break;
724  case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
725  case MCBinaryExpr::Mod: Result = LHS % RHS; break;
726  case MCBinaryExpr::Mul: Result = LHS * RHS; break;
727  case MCBinaryExpr::NE: Result = LHS != RHS; break;
728  case MCBinaryExpr::Or: Result = LHS | RHS; break;
729  case MCBinaryExpr::Shl: Result = LHS << RHS; break;
730  case MCBinaryExpr::Shr: Result = LHS >> RHS; break;
731  case MCBinaryExpr::Sub: Result = LHS - RHS; break;
732  case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
733  }
734 
735  Res = MCValue::get(Result);
736  return true;
737  }
738  }
739 
740  llvm_unreachable("Invalid assembly expression kind!");
741 }
742 
743 const MCSection *MCExpr::FindAssociatedSection() const {
744  switch (getKind()) {
745  case Target:
746  // We never look through target specific expressions.
747  return cast<MCTargetExpr>(this)->FindAssociatedSection();
748 
749  case Constant:
750  return MCSymbol::AbsolutePseudoSection;
751 
752  case SymbolRef: {
753  const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
754  const MCSymbol &Sym = SRE->getSymbol();
755 
756  if (Sym.isDefined())
757  return &Sym.getSection();
758 
759  return 0;
760  }
761 
762  case Unary:
763  return cast<MCUnaryExpr>(this)->getSubExpr()->FindAssociatedSection();
764 
765  case Binary: {
766  const MCBinaryExpr *BE = cast<MCBinaryExpr>(this);
767  const MCSection *LHS_S = BE->getLHS()->FindAssociatedSection();
768  const MCSection *RHS_S = BE->getRHS()->FindAssociatedSection();
769 
770  // If either section is absolute, return the other.
771  if (LHS_S == MCSymbol::AbsolutePseudoSection)
772  return RHS_S;
773  if (RHS_S == MCSymbol::AbsolutePseudoSection)
774  return LHS_S;
775 
776  // Otherwise, return the first non-null section.
777  return LHS_S ? LHS_S : RHS_S;
778  }
779  }
780 
781  llvm_unreachable("Invalid assembly expression kind!");
782 }
llvm::ARM_PROC::A
Definition: ARMBaseInfo.h:98
llvm::MCUnaryExpr::Not
Bitwise negation.
Definition: MCExpr.h:308
llvm::MCSymbolRefExpr::getSymbol
const MCSymbol & getSymbol() const
Definition: MCExpr.h:283
llvm::MCBinaryExpr::And
Bitwise and.
Definition: MCExpr.h:360
llvm::MCBinaryExpr::Mul
Multiplication.
Definition: MCExpr.h:374
llvm::MCExpr::getKind
ExprKind getKind() const
Definition: MCExpr.h:61
llvm::MCUnaryExpr::Plus
Unary plus.
Definition: MCExpr.h:309
llvm::MCValue::get
static MCValue get(const MCSymbolRefExpr *SymA, const MCSymbolRefExpr *SymB=0, int64_t Val=0)
Definition: MCValue.h:55
llvm::MCBinaryExpr::EQ
Equality comparison.
Definition: MCExpr.h:362
llvm::MCBinaryExpr::Or
Bitwise or.
Definition: MCExpr.h:376
llvm::MCBinaryExpr::Shr
Shift right (arithmetic or logical, depending on target)
Definition: MCExpr.h:378
llvm::MCSymbol::getSection
const MCSection & getSection() const
Definition: MCSymbol.h:111
llvm_unreachable
#define llvm_unreachable(msg)
Definition: ErrorHandling.h:103
STATISTIC
#define STATISTIC(VARNAME, DESC)
Definition: Statistic.h:164
llvm::MCBinaryExpr::LOr
Logical or.
Definition: MCExpr.h:368
llvm::MCBinaryExpr::Mod
Signed remainder.
Definition: MCExpr.h:373
llvm::MCUnaryExpr
MCUnaryExpr - Unary assembler expressions.
Definition: MCExpr.h:303
llvm::MCBinaryExpr::Div
Signed division.
Definition: MCExpr.h:361
llvm::MCExpr::Unary
Unary expressions.
Definition: MCExpr.h:37
llvm::MCBinaryExpr::Shl
Shift left.
Definition: MCExpr.h:377
llvm::MCBinaryExpr::getLHS
const MCExpr * getLHS() const
getLHS - Get the left-hand side expression of the binary operator.
Definition: MCExpr.h:477
if
* if(!EatIfPresent(lltok::kw_thread_local)) return false
llvm::Constant
LLVM Constant Representation.
Definition: Constant.h:41
EvaluateSymbolicAdd
static bool EvaluateSymbolicAdd(const MCAssembler *Asm, const MCAsmLayout *Layout, const SectionAddrMap *Addrs, bool InSet, const MCValue &LHS, const MCSymbolRefExpr *RHS_A, const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst, MCValue &Res)
Evaluate the result of an add between (conceptually) two MCValues.
Definition: MCExpr.cpp:544
llvm::MCUnaryExpr::LNot
Logical negation.
Definition: MCExpr.h:306
llvm::MCExpr::FindAssociatedSection
const MCSection * FindAssociatedSection() const
Definition: MCExpr.cpp:743
llvm::MCBinaryExpr::LAnd
Logical and.
Definition: MCExpr.h:367
llvm::MCValue::getSymB
const MCSymbolRefExpr * getSymB() const
Definition: MCValue.h:44
llvm::MCBinaryExpr
MCBinaryExpr - Binary assembler expressions.
Definition: MCExpr.h:356
llvm::MCExpr::EvaluateAsRelocatable
bool EvaluateAsRelocatable(MCValue &Res, const MCAsmLayout &Layout) const
Definition: MCExpr.cpp:603
llvm::MCValue::getSymA
const MCSymbolRefExpr * getSymA() const
Definition: MCValue.h:43
stats
block placement stats
Definition: MachineBlockPlacement.cpp:1169
llvm::MCBinaryExpr::NE
Inequality comparison.
Definition: MCExpr.h:375
llvm::MCExpr::EvaluateAsRelocatableImpl
bool EvaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm, const MCAsmLayout *Layout, const SectionAddrMap *Addrs, bool InSet) const
Definition: MCExpr.cpp:609
llvm::MCBinaryExpr::Xor
Bitwise exclusive or.
Definition: MCExpr.h:380
llvm::MCBinaryExpr::getRHS
const MCExpr * getRHS() const
getRHS - Get the right-hand side expression of the binary operator.
Definition: MCExpr.h:480
llvm::MCUnaryExpr::getSubExpr
const MCExpr * getSubExpr() const
getSubExpr - Get the child of this unary expression.
Definition: MCExpr.h:346
llvm::MCExpr::print
void print(raw_ostream &OS) const
Definition: MCExpr.cpp:31
llvm::MCSymbol::getName
StringRef getName() const
getName - Get the symbol name.
Definition: MCSymbol.h:70
llvm::MCBinaryExpr::getOpcode
Opcode getOpcode() const
getOpcode - Get the kind of this binary expression.
Definition: MCExpr.h:474
llvm::MCExpr::SymbolRef
References to labels and assigned expressions.
Definition: MCExpr.h:36
llvm::MCUnaryExpr::Minus
Unary minus.
Definition: MCExpr.h:307
llvm::MCSymbolRefExpr::getKind
VariantKind getKind() const
Definition: MCExpr.h:285
llvm::Value
LLVM Value Representation.
Definition: Value.h:66
llvm::MCExpr::Constant
Constant expressions.
Definition: MCExpr.h:35
llvm::MCExpr::Binary
Binary expressions.
Definition: MCExpr.h:34
llvm::MCAsmLayout::getAssembler
MCAssembler & getAssembler() const
Get the assembler object this is a layout for.
Definition: MCAsmLayout.h:61
llvm::raw_ostream
Definition: raw_ostream.h:31
llvm::MCBinaryExpr::Sub
Subtraction.
Definition: MCExpr.h:379
raw_ostream.h
llvm::MCExpr::Target
Target specific expression.
Definition: MCExpr.h:38
llvm::MCSymbolRefExpr::getVariantKindName
static StringRef getVariantKindName(VariantKind Kind)
Definition: MCExpr.cpp:169
llvm::MCUnaryExpr::getOpcode
Opcode getOpcode() const
getOpcode - Get the kind of this unary expression.
Definition: MCExpr.h:343

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