1 //===- MCExpr.cpp - Assembly Level Expression Implementation --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCExpr.h"
11 #include "llvm/ADT/Statistic.h"
12 #include "llvm/ADT/StringSwitch.h"
13 #include "llvm/Config/llvm-config.h"
14 #include "llvm/MC/MCAsmBackend.h"
15 #include "llvm/MC/MCAsmInfo.h"
16 #include "llvm/MC/MCAsmLayout.h"
17 #include "llvm/MC/MCAssembler.h"
18 #include "llvm/MC/MCContext.h"
19 #include "llvm/MC/MCObjectWriter.h"
20 #include "llvm/MC/MCSymbol.h"
21 #include "llvm/MC/MCValue.h"
22 #include "llvm/Support/Casting.h"
23 #include "llvm/Support/Compiler.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/raw_ostream.h"
32 #define DEBUG_TYPE "mcexpr"
37 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
39 } // end namespace stats
40 } // end anonymous namespace
42 void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens) const {
45 return cast<MCTargetExpr>(this)->printImpl(OS, MAI);
46 case MCExpr::Constant:
47 OS << cast<MCConstantExpr>(*this).getValue();
50 case MCExpr::SymbolRef: {
51 const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
52 const MCSymbol &Sym = SRE.getSymbol();
53 // Parenthesize names that start with $ so that they don't look like
56 !InParens && !Sym.getName().empty() && Sym.getName()[0] == '$';
64 if (SRE.getKind() != MCSymbolRefExpr::VK_None)
65 SRE.printVariantKind(OS);
71 const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
72 switch (UE.getOpcode()) {
73 case MCUnaryExpr::LNot: OS << '!'; break;
74 case MCUnaryExpr::Minus: OS << '-'; break;
75 case MCUnaryExpr::Not: OS << '~'; break;
76 case MCUnaryExpr::Plus: OS << '+'; break;
78 bool Binary = UE.getSubExpr()->getKind() == MCExpr::Binary;
79 if (Binary) OS << "(";
80 UE.getSubExpr()->print(OS, MAI);
81 if (Binary) OS << ")";
85 case MCExpr::Binary: {
86 const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
88 // Only print parens around the LHS if it is non-trivial.
89 if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
90 BE.getLHS()->print(OS, MAI);
93 BE.getLHS()->print(OS, MAI);
97 switch (BE.getOpcode()) {
98 case MCBinaryExpr::Add:
99 // Print "X-42" instead of "X+-42".
100 if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
101 if (RHSC->getValue() < 0) {
102 OS << RHSC->getValue();
109 case MCBinaryExpr::AShr: OS << ">>"; break;
110 case MCBinaryExpr::And: OS << '&'; break;
111 case MCBinaryExpr::Div: OS << '/'; break;
112 case MCBinaryExpr::EQ: OS << "=="; break;
113 case MCBinaryExpr::GT: OS << '>'; break;
114 case MCBinaryExpr::GTE: OS << ">="; break;
115 case MCBinaryExpr::LAnd: OS << "&&"; break;
116 case MCBinaryExpr::LOr: OS << "||"; break;
117 case MCBinaryExpr::LShr: OS << ">>"; break;
118 case MCBinaryExpr::LT: OS << '<'; break;
119 case MCBinaryExpr::LTE: OS << "<="; break;
120 case MCBinaryExpr::Mod: OS << '%'; break;
121 case MCBinaryExpr::Mul: OS << '*'; break;
122 case MCBinaryExpr::NE: OS << "!="; break;
123 case MCBinaryExpr::Or: OS << '|'; break;
124 case MCBinaryExpr::Shl: OS << "<<"; break;
125 case MCBinaryExpr::Sub: OS << '-'; break;
126 case MCBinaryExpr::Xor: OS << '^'; break;
129 // Only print parens around the LHS if it is non-trivial.
130 if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
131 BE.getRHS()->print(OS, MAI);
134 BE.getRHS()->print(OS, MAI);
141 llvm_unreachable("Invalid expression kind!");
144 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
145 LLVM_DUMP_METHOD void MCExpr::dump() const {
153 const MCBinaryExpr *MCBinaryExpr::create(Opcode Opc, const MCExpr *LHS,
154 const MCExpr *RHS, MCContext &Ctx,
156 return new (Ctx) MCBinaryExpr(Opc, LHS, RHS, Loc);
159 const MCUnaryExpr *MCUnaryExpr::create(Opcode Opc, const MCExpr *Expr,
160 MCContext &Ctx, SMLoc Loc) {
161 return new (Ctx) MCUnaryExpr(Opc, Expr, Loc);
164 const MCConstantExpr *MCConstantExpr::create(int64_t Value, MCContext &Ctx) {
165 return new (Ctx) MCConstantExpr(Value);
170 MCSymbolRefExpr::MCSymbolRefExpr(const MCSymbol *Symbol, VariantKind Kind,
171 const MCAsmInfo *MAI, SMLoc Loc)
172 : MCExpr(MCExpr::SymbolRef, Loc), Kind(Kind),
173 UseParensForSymbolVariant(MAI->useParensForSymbolVariant()),
174 HasSubsectionsViaSymbols(MAI->hasSubsectionsViaSymbols()),
179 const MCSymbolRefExpr *MCSymbolRefExpr::create(const MCSymbol *Sym,
181 MCContext &Ctx, SMLoc Loc) {
182 return new (Ctx) MCSymbolRefExpr(Sym, Kind, Ctx.getAsmInfo(), Loc);
185 const MCSymbolRefExpr *MCSymbolRefExpr::create(StringRef Name, VariantKind Kind,
187 return create(Ctx.getOrCreateSymbol(Name), Kind, Ctx);
190 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
192 case VK_Invalid: return "<<invalid>>";
193 case VK_None: return "<<none>>";
195 case VK_DTPOFF: return "DTPOFF";
196 case VK_DTPREL: return "DTPREL";
197 case VK_GOT: return "GOT";
198 case VK_GOTOFF: return "GOTOFF";
199 case VK_GOTREL: return "GOTREL";
200 case VK_GOTPCREL: return "GOTPCREL";
201 case VK_GOTTPOFF: return "GOTTPOFF";
202 case VK_INDNTPOFF: return "INDNTPOFF";
203 case VK_NTPOFF: return "NTPOFF";
204 case VK_GOTNTPOFF: return "GOTNTPOFF";
205 case VK_PLT: return "PLT";
206 case VK_TLSGD: return "TLSGD";
207 case VK_TLSLD: return "TLSLD";
208 case VK_TLSLDM: return "TLSLDM";
209 case VK_TPOFF: return "TPOFF";
210 case VK_TPREL: return "TPREL";
211 case VK_TLSCALL: return "tlscall";
212 case VK_TLSDESC: return "tlsdesc";
213 case VK_TLVP: return "TLVP";
214 case VK_TLVPPAGE: return "TLVPPAGE";
215 case VK_TLVPPAGEOFF: return "TLVPPAGEOFF";
216 case VK_PAGE: return "PAGE";
217 case VK_PAGEOFF: return "PAGEOFF";
218 case VK_GOTPAGE: return "GOTPAGE";
219 case VK_GOTPAGEOFF: return "GOTPAGEOFF";
220 case VK_SECREL: return "SECREL32";
221 case VK_SIZE: return "SIZE";
222 case VK_WEAKREF: return "WEAKREF";
223 case VK_X86_ABS8: return "ABS8";
224 case VK_ARM_NONE: return "none";
225 case VK_ARM_GOT_PREL: return "GOT_PREL";
226 case VK_ARM_TARGET1: return "target1";
227 case VK_ARM_TARGET2: return "target2";
228 case VK_ARM_PREL31: return "prel31";
229 case VK_ARM_SBREL: return "sbrel";
230 case VK_ARM_TLSLDO: return "tlsldo";
231 case VK_ARM_TLSDESCSEQ: return "tlsdescseq";
232 case VK_AVR_NONE: return "none";
233 case VK_AVR_LO8: return "lo8";
234 case VK_AVR_HI8: return "hi8";
235 case VK_AVR_HLO8: return "hlo8";
236 case VK_AVR_DIFF8: return "diff8";
237 case VK_AVR_DIFF16: return "diff16";
238 case VK_AVR_DIFF32: return "diff32";
239 case VK_PPC_LO: return "l";
240 case VK_PPC_HI: return "h";
241 case VK_PPC_HA: return "ha";
242 case VK_PPC_HIGH: return "high";
243 case VK_PPC_HIGHA: return "higha";
244 case VK_PPC_HIGHER: return "higher";
245 case VK_PPC_HIGHERA: return "highera";
246 case VK_PPC_HIGHEST: return "highest";
247 case VK_PPC_HIGHESTA: return "highesta";
248 case VK_PPC_GOT_LO: return "got@l";
249 case VK_PPC_GOT_HI: return "got@h";
250 case VK_PPC_GOT_HA: return "got@ha";
251 case VK_PPC_TOCBASE: return "tocbase";
252 case VK_PPC_TOC: return "toc";
253 case VK_PPC_TOC_LO: return "toc@l";
254 case VK_PPC_TOC_HI: return "toc@h";
255 case VK_PPC_TOC_HA: return "toc@ha";
256 case VK_PPC_DTPMOD: return "dtpmod";
257 case VK_PPC_TPREL_LO: return "tprel@l";
258 case VK_PPC_TPREL_HI: return "tprel@h";
259 case VK_PPC_TPREL_HA: return "tprel@ha";
260 case VK_PPC_TPREL_HIGH: return "tprel@high";
261 case VK_PPC_TPREL_HIGHA: return "tprel@higha";
262 case VK_PPC_TPREL_HIGHER: return "tprel@higher";
263 case VK_PPC_TPREL_HIGHERA: return "tprel@highera";
264 case VK_PPC_TPREL_HIGHEST: return "tprel@highest";
265 case VK_PPC_TPREL_HIGHESTA: return "tprel@highesta";
266 case VK_PPC_DTPREL_LO: return "dtprel@l";
267 case VK_PPC_DTPREL_HI: return "dtprel@h";
268 case VK_PPC_DTPREL_HA: return "dtprel@ha";
269 case VK_PPC_DTPREL_HIGH: return "dtprel@high";
270 case VK_PPC_DTPREL_HIGHA: return "dtprel@higha";
271 case VK_PPC_DTPREL_HIGHER: return "dtprel@higher";
272 case VK_PPC_DTPREL_HIGHERA: return "dtprel@highera";
273 case VK_PPC_DTPREL_HIGHEST: return "dtprel@highest";
274 case VK_PPC_DTPREL_HIGHESTA: return "dtprel@highesta";
275 case VK_PPC_GOT_TPREL: return "got@tprel";
276 case VK_PPC_GOT_TPREL_LO: return "got@tprel@l";
277 case VK_PPC_GOT_TPREL_HI: return "got@tprel@h";
278 case VK_PPC_GOT_TPREL_HA: return "got@tprel@ha";
279 case VK_PPC_GOT_DTPREL: return "got@dtprel";
280 case VK_PPC_GOT_DTPREL_LO: return "got@dtprel@l";
281 case VK_PPC_GOT_DTPREL_HI: return "got@dtprel@h";
282 case VK_PPC_GOT_DTPREL_HA: return "got@dtprel@ha";
283 case VK_PPC_TLS: return "tls";
284 case VK_PPC_GOT_TLSGD: return "got@tlsgd";
285 case VK_PPC_GOT_TLSGD_LO: return "got@tlsgd@l";
286 case VK_PPC_GOT_TLSGD_HI: return "got@tlsgd@h";
287 case VK_PPC_GOT_TLSGD_HA: return "got@tlsgd@ha";
288 case VK_PPC_TLSGD: return "tlsgd";
289 case VK_PPC_GOT_TLSLD: return "got@tlsld";
290 case VK_PPC_GOT_TLSLD_LO: return "got@tlsld@l";
291 case VK_PPC_GOT_TLSLD_HI: return "got@tlsld@h";
292 case VK_PPC_GOT_TLSLD_HA: return "got@tlsld@ha";
293 case VK_PPC_TLSLD: return "tlsld";
294 case VK_PPC_LOCAL: return "local";
295 case VK_COFF_IMGREL32: return "IMGREL";
296 case VK_Hexagon_PCREL: return "PCREL";
297 case VK_Hexagon_LO16: return "LO16";
298 case VK_Hexagon_HI16: return "HI16";
299 case VK_Hexagon_GPREL: return "GPREL";
300 case VK_Hexagon_GD_GOT: return "GDGOT";
301 case VK_Hexagon_LD_GOT: return "LDGOT";
302 case VK_Hexagon_GD_PLT: return "GDPLT";
303 case VK_Hexagon_LD_PLT: return "LDPLT";
304 case VK_Hexagon_IE: return "IE";
305 case VK_Hexagon_IE_GOT: return "IEGOT";
306 case VK_WebAssembly_FUNCTION: return "FUNCTION";
307 case VK_WebAssembly_GLOBAL: return "GLOBAL";
308 case VK_WebAssembly_TYPEINDEX: return "TYPEINDEX";
309 case VK_WebAssembly_EVENT: return "EVENT";
310 case VK_AMDGPU_GOTPCREL32_LO: return "gotpcrel32@lo";
311 case VK_AMDGPU_GOTPCREL32_HI: return "gotpcrel32@hi";
312 case VK_AMDGPU_REL32_LO: return "rel32@lo";
313 case VK_AMDGPU_REL32_HI: return "rel32@hi";
314 case VK_AMDGPU_REL64: return "rel64";
316 llvm_unreachable("Invalid variant kind");
319 MCSymbolRefExpr::VariantKind
320 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
321 return StringSwitch<VariantKind>(Name.lower())
322 .Case("dtprel", VK_DTPREL)
323 .Case("dtpoff", VK_DTPOFF)
325 .Case("gotoff", VK_GOTOFF)
326 .Case("gotrel", VK_GOTREL)
327 .Case("gotpcrel", VK_GOTPCREL)
328 .Case("gottpoff", VK_GOTTPOFF)
329 .Case("indntpoff", VK_INDNTPOFF)
330 .Case("ntpoff", VK_NTPOFF)
331 .Case("gotntpoff", VK_GOTNTPOFF)
333 .Case("tlscall", VK_TLSCALL)
334 .Case("tlsdesc", VK_TLSDESC)
335 .Case("tlsgd", VK_TLSGD)
336 .Case("tlsld", VK_TLSLD)
337 .Case("tlsldm", VK_TLSLDM)
338 .Case("tpoff", VK_TPOFF)
339 .Case("tprel", VK_TPREL)
340 .Case("tlvp", VK_TLVP)
341 .Case("tlvppage", VK_TLVPPAGE)
342 .Case("tlvppageoff", VK_TLVPPAGEOFF)
343 .Case("page", VK_PAGE)
344 .Case("pageoff", VK_PAGEOFF)
345 .Case("gotpage", VK_GOTPAGE)
346 .Case("gotpageoff", VK_GOTPAGEOFF)
347 .Case("imgrel", VK_COFF_IMGREL32)
348 .Case("secrel32", VK_SECREL)
349 .Case("size", VK_SIZE)
350 .Case("abs8", VK_X86_ABS8)
351 .Case("l", VK_PPC_LO)
352 .Case("h", VK_PPC_HI)
353 .Case("ha", VK_PPC_HA)
354 .Case("high", VK_PPC_HIGH)
355 .Case("higha", VK_PPC_HIGHA)
356 .Case("higher", VK_PPC_HIGHER)
357 .Case("highera", VK_PPC_HIGHERA)
358 .Case("highest", VK_PPC_HIGHEST)
359 .Case("highesta", VK_PPC_HIGHESTA)
360 .Case("got@l", VK_PPC_GOT_LO)
361 .Case("got@h", VK_PPC_GOT_HI)
362 .Case("got@ha", VK_PPC_GOT_HA)
363 .Case("local", VK_PPC_LOCAL)
364 .Case("tocbase", VK_PPC_TOCBASE)
365 .Case("toc", VK_PPC_TOC)
366 .Case("toc@l", VK_PPC_TOC_LO)
367 .Case("toc@h", VK_PPC_TOC_HI)
368 .Case("toc@ha", VK_PPC_TOC_HA)
369 .Case("tls", VK_PPC_TLS)
370 .Case("dtpmod", VK_PPC_DTPMOD)
371 .Case("tprel@l", VK_PPC_TPREL_LO)
372 .Case("tprel@h", VK_PPC_TPREL_HI)
373 .Case("tprel@ha", VK_PPC_TPREL_HA)
374 .Case("tprel@high", VK_PPC_TPREL_HIGH)
375 .Case("tprel@higha", VK_PPC_TPREL_HIGHA)
376 .Case("tprel@higher", VK_PPC_TPREL_HIGHER)
377 .Case("tprel@highera", VK_PPC_TPREL_HIGHERA)
378 .Case("tprel@highest", VK_PPC_TPREL_HIGHEST)
379 .Case("tprel@highesta", VK_PPC_TPREL_HIGHESTA)
380 .Case("dtprel@l", VK_PPC_DTPREL_LO)
381 .Case("dtprel@h", VK_PPC_DTPREL_HI)
382 .Case("dtprel@ha", VK_PPC_DTPREL_HA)
383 .Case("dtprel@high", VK_PPC_DTPREL_HIGH)
384 .Case("dtprel@higha", VK_PPC_DTPREL_HIGHA)
385 .Case("dtprel@higher", VK_PPC_DTPREL_HIGHER)
386 .Case("dtprel@highera", VK_PPC_DTPREL_HIGHERA)
387 .Case("dtprel@highest", VK_PPC_DTPREL_HIGHEST)
388 .Case("dtprel@highesta", VK_PPC_DTPREL_HIGHESTA)
389 .Case("got@tprel", VK_PPC_GOT_TPREL)
390 .Case("got@tprel@l", VK_PPC_GOT_TPREL_LO)
391 .Case("got@tprel@h", VK_PPC_GOT_TPREL_HI)
392 .Case("got@tprel@ha", VK_PPC_GOT_TPREL_HA)
393 .Case("got@dtprel", VK_PPC_GOT_DTPREL)
394 .Case("got@dtprel@l", VK_PPC_GOT_DTPREL_LO)
395 .Case("got@dtprel@h", VK_PPC_GOT_DTPREL_HI)
396 .Case("got@dtprel@ha", VK_PPC_GOT_DTPREL_HA)
397 .Case("got@tlsgd", VK_PPC_GOT_TLSGD)
398 .Case("got@tlsgd@l", VK_PPC_GOT_TLSGD_LO)
399 .Case("got@tlsgd@h", VK_PPC_GOT_TLSGD_HI)
400 .Case("got@tlsgd@ha", VK_PPC_GOT_TLSGD_HA)
401 .Case("got@tlsld", VK_PPC_GOT_TLSLD)
402 .Case("got@tlsld@l", VK_PPC_GOT_TLSLD_LO)
403 .Case("got@tlsld@h", VK_PPC_GOT_TLSLD_HI)
404 .Case("got@tlsld@ha", VK_PPC_GOT_TLSLD_HA)
405 .Case("gdgot", VK_Hexagon_GD_GOT)
406 .Case("gdplt", VK_Hexagon_GD_PLT)
407 .Case("iegot", VK_Hexagon_IE_GOT)
408 .Case("ie", VK_Hexagon_IE)
409 .Case("ldgot", VK_Hexagon_LD_GOT)
410 .Case("ldplt", VK_Hexagon_LD_PLT)
411 .Case("pcrel", VK_Hexagon_PCREL)
412 .Case("none", VK_ARM_NONE)
413 .Case("got_prel", VK_ARM_GOT_PREL)
414 .Case("target1", VK_ARM_TARGET1)
415 .Case("target2", VK_ARM_TARGET2)
416 .Case("prel31", VK_ARM_PREL31)
417 .Case("sbrel", VK_ARM_SBREL)
418 .Case("tlsldo", VK_ARM_TLSLDO)
419 .Case("lo8", VK_AVR_LO8)
420 .Case("hi8", VK_AVR_HI8)
421 .Case("hlo8", VK_AVR_HLO8)
422 .Case("function", VK_WebAssembly_FUNCTION)
423 .Case("global", VK_WebAssembly_GLOBAL)
424 .Case("typeindex", VK_WebAssembly_TYPEINDEX)
425 .Case("event", VK_WebAssembly_EVENT)
426 .Case("gotpcrel32@lo", VK_AMDGPU_GOTPCREL32_LO)
427 .Case("gotpcrel32@hi", VK_AMDGPU_GOTPCREL32_HI)
428 .Case("rel32@lo", VK_AMDGPU_REL32_LO)
429 .Case("rel32@hi", VK_AMDGPU_REL32_HI)
430 .Case("rel64", VK_AMDGPU_REL64)
431 .Default(VK_Invalid);
434 void MCSymbolRefExpr::printVariantKind(raw_ostream &OS) const {
435 if (UseParensForSymbolVariant)
436 OS << '(' << MCSymbolRefExpr::getVariantKindName(getKind()) << ')';
438 OS << '@' << MCSymbolRefExpr::getVariantKindName(getKind());
443 void MCTargetExpr::anchor() {}
447 bool MCExpr::evaluateAsAbsolute(int64_t &Res) const {
448 return evaluateAsAbsolute(Res, nullptr, nullptr, nullptr);
451 bool MCExpr::evaluateAsAbsolute(int64_t &Res,
452 const MCAsmLayout &Layout) const {
453 return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr);
456 bool MCExpr::evaluateAsAbsolute(int64_t &Res,
457 const MCAsmLayout &Layout,
458 const SectionAddrMap &Addrs) const {
459 return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs);
462 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
463 return evaluateAsAbsolute(Res, &Asm, nullptr, nullptr);
466 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm) const {
467 return evaluateAsAbsolute(Res, Asm, nullptr, nullptr);
470 bool MCExpr::evaluateKnownAbsolute(int64_t &Res,
471 const MCAsmLayout &Layout) const {
472 return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr,
476 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
477 const MCAsmLayout *Layout,
478 const SectionAddrMap *Addrs) const {
479 // FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us
480 // absolutize differences across sections and that is what the MachO writer
482 return evaluateAsAbsolute(Res, Asm, Layout, Addrs, Addrs);
485 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
486 const MCAsmLayout *Layout,
487 const SectionAddrMap *Addrs, bool InSet) const {
490 // Fast path constants.
491 if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
492 Res = CE->getValue();
497 evaluateAsRelocatableImpl(Value, Asm, Layout, nullptr, Addrs, InSet);
499 // Record the current value.
500 Res = Value.getConstant();
502 return IsRelocatable && Value.isAbsolute();
505 /// Helper method for \see EvaluateSymbolAdd().
506 static void AttemptToFoldSymbolOffsetDifference(
507 const MCAssembler *Asm, const MCAsmLayout *Layout,
508 const SectionAddrMap *Addrs, bool InSet, const MCSymbolRefExpr *&A,
509 const MCSymbolRefExpr *&B, int64_t &Addend) {
513 const MCSymbol &SA = A->getSymbol();
514 const MCSymbol &SB = B->getSymbol();
516 if (SA.isUndefined() || SB.isUndefined())
519 if (!Asm->getWriter().isSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
522 if (SA.getFragment() == SB.getFragment() && !SA.isVariable() &&
523 !SA.isUnset() && !SB.isVariable() && !SB.isUnset()) {
524 Addend += (SA.getOffset() - SB.getOffset());
526 // Pointers to Thumb symbols need to have their low-bit set to allow
528 if (Asm->isThumbFunc(&SA))
531 // If symbol is labeled as micromips, we set low-bit to ensure
532 // correct offset in .gcc_except_table
533 if (Asm->getBackend().isMicroMips(&SA))
536 // Clear the symbol expr pointers to indicate we have folded these
545 const MCSection &SecA = *SA.getFragment()->getParent();
546 const MCSection &SecB = *SB.getFragment()->getParent();
548 if ((&SecA != &SecB) && !Addrs)
552 Addend += Layout->getSymbolOffset(A->getSymbol()) -
553 Layout->getSymbolOffset(B->getSymbol());
554 if (Addrs && (&SecA != &SecB))
555 Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
557 // Pointers to Thumb symbols need to have their low-bit set to allow
559 if (Asm->isThumbFunc(&SA))
562 // If symbol is labeled as micromips, we set low-bit to ensure
563 // correct offset in .gcc_except_table
564 if (Asm->getBackend().isMicroMips(&SA))
567 // Clear the symbol expr pointers to indicate we have folded these
572 /// Evaluate the result of an add between (conceptually) two MCValues.
574 /// This routine conceptually attempts to construct an MCValue:
575 /// Result = (Result_A - Result_B + Result_Cst)
576 /// from two MCValue's LHS and RHS where
577 /// Result = LHS + RHS
579 /// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
581 /// This routine attempts to aggresively fold the operands such that the result
582 /// is representable in an MCValue, but may not always succeed.
584 /// \returns True on success, false if the result is not representable in an
587 /// NOTE: It is really important to have both the Asm and Layout arguments.
588 /// They might look redundant, but this function can be used before layout
589 /// is done (see the object streamer for example) and having the Asm argument
590 /// lets us avoid relaxations early.
592 EvaluateSymbolicAdd(const MCAssembler *Asm, const MCAsmLayout *Layout,
593 const SectionAddrMap *Addrs, bool InSet, const MCValue &LHS,
594 const MCSymbolRefExpr *RHS_A, const MCSymbolRefExpr *RHS_B,
595 int64_t RHS_Cst, MCValue &Res) {
596 // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy
597 // about dealing with modifiers. This will ultimately bite us, one day.
598 const MCSymbolRefExpr *LHS_A = LHS.getSymA();
599 const MCSymbolRefExpr *LHS_B = LHS.getSymB();
600 int64_t LHS_Cst = LHS.getConstant();
602 // Fold the result constant immediately.
603 int64_t Result_Cst = LHS_Cst + RHS_Cst;
605 assert((!Layout || Asm) &&
606 "Must have an assembler object if layout is given!");
608 // If we have a layout, we can fold resolved differences. Do not do this if
609 // the backend requires this to be emitted as individual relocations, unless
610 // the InSet flag is set to get the current difference anyway (used for
611 // example to calculate symbol sizes).
613 (InSet || !Asm->getBackend().requiresDiffExpressionRelocations())) {
614 // First, fold out any differences which are fully resolved. By
615 // reassociating terms in
616 // Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
617 // we have the four possible differences:
622 // Since we are attempting to be as aggressive as possible about folding, we
623 // attempt to evaluate each possible alternative.
624 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
626 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
628 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
630 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
634 // We can't represent the addition or subtraction of two symbols.
635 if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
638 // At this point, we have at most one additive symbol and one subtractive
639 // symbol -- find them.
640 const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
641 const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;
643 Res = MCValue::get(A, B, Result_Cst);
647 bool MCExpr::evaluateAsRelocatable(MCValue &Res,
648 const MCAsmLayout *Layout,
649 const MCFixup *Fixup) const {
650 MCAssembler *Assembler = Layout ? &Layout->getAssembler() : nullptr;
651 return evaluateAsRelocatableImpl(Res, Assembler, Layout, Fixup, nullptr,
655 bool MCExpr::evaluateAsValue(MCValue &Res, const MCAsmLayout &Layout) const {
656 MCAssembler *Assembler = &Layout.getAssembler();
657 return evaluateAsRelocatableImpl(Res, Assembler, &Layout, nullptr, nullptr,
661 static bool canExpand(const MCSymbol &Sym, bool InSet) {
662 const MCExpr *Expr = Sym.getVariableValue();
663 const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr);
665 if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF)
671 return !Sym.isInSection();
674 bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
675 const MCAsmLayout *Layout,
676 const MCFixup *Fixup,
677 const SectionAddrMap *Addrs,
679 ++stats::MCExprEvaluate;
683 return cast<MCTargetExpr>(this)->evaluateAsRelocatableImpl(Res, Layout,
687 Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
691 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
692 const MCSymbol &Sym = SRE->getSymbol();
694 // Evaluate recursively if this is a variable.
695 if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None &&
696 canExpand(Sym, InSet)) {
697 bool IsMachO = SRE->hasSubsectionsViaSymbols();
698 if (Sym.getVariableValue()->evaluateAsRelocatableImpl(
699 Res, Asm, Layout, Fixup, Addrs, InSet || IsMachO)) {
703 const MCSymbolRefExpr *A = Res.getSymA();
704 const MCSymbolRefExpr *B = Res.getSymB();
705 // FIXME: This is small hack. Given
708 // the OS X assembler will completely drop the 4. We should probably
709 // include it in the relocation or produce an error if that is not
711 // Allow constant expressions.
714 // Allows aliases with zero offset.
715 if (Res.getConstant() == 0 && (!A || !B))
720 Res = MCValue::get(SRE, nullptr, 0);
725 const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
728 if (!AUE->getSubExpr()->evaluateAsRelocatableImpl(Value, Asm, Layout, Fixup,
732 switch (AUE->getOpcode()) {
733 case MCUnaryExpr::LNot:
734 if (!Value.isAbsolute())
736 Res = MCValue::get(!Value.getConstant());
738 case MCUnaryExpr::Minus:
739 /// -(a - b + const) ==> (b - a - const)
740 if (Value.getSymA() && !Value.getSymB())
743 // The cast avoids undefined behavior if the constant is INT64_MIN.
744 Res = MCValue::get(Value.getSymB(), Value.getSymA(),
745 -(uint64_t)Value.getConstant());
747 case MCUnaryExpr::Not:
748 if (!Value.isAbsolute())
750 Res = MCValue::get(~Value.getConstant());
752 case MCUnaryExpr::Plus:
761 const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
762 MCValue LHSValue, RHSValue;
764 if (!ABE->getLHS()->evaluateAsRelocatableImpl(LHSValue, Asm, Layout, Fixup,
766 !ABE->getRHS()->evaluateAsRelocatableImpl(RHSValue, Asm, Layout, Fixup,
768 // Check if both are Target Expressions, see if we can compare them.
769 if (const MCTargetExpr *L = dyn_cast<MCTargetExpr>(ABE->getLHS()))
770 if (const MCTargetExpr *R = cast<MCTargetExpr>(ABE->getRHS())) {
771 switch (ABE->getOpcode()) {
772 case MCBinaryExpr::EQ:
773 Res = MCValue::get((L->isEqualTo(R)) ? -1 : 0);
775 case MCBinaryExpr::NE:
776 Res = MCValue::get((R->isEqualTo(R)) ? 0 : -1);
784 // We only support a few operations on non-constant expressions, handle
786 if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
787 switch (ABE->getOpcode()) {
790 case MCBinaryExpr::Sub:
791 // Negate RHS and add.
792 // The cast avoids undefined behavior if the constant is INT64_MIN.
793 return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
794 RHSValue.getSymB(), RHSValue.getSymA(),
795 -(uint64_t)RHSValue.getConstant(), Res);
797 case MCBinaryExpr::Add:
798 return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
799 RHSValue.getSymA(), RHSValue.getSymB(),
800 RHSValue.getConstant(), Res);
804 // FIXME: We need target hooks for the evaluation. It may be limited in
805 // width, and gas defines the result of comparisons differently from
807 int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
809 auto Op = ABE->getOpcode();
811 case MCBinaryExpr::AShr: Result = LHS >> RHS; break;
812 case MCBinaryExpr::Add: Result = LHS + RHS; break;
813 case MCBinaryExpr::And: Result = LHS & RHS; break;
814 case MCBinaryExpr::Div:
815 case MCBinaryExpr::Mod:
816 // Handle division by zero. gas just emits a warning and keeps going,
817 // we try to be stricter.
818 // FIXME: Currently the caller of this function has no way to understand
819 // we're bailing out because of 'division by zero'. Therefore, it will
820 // emit a 'expected relocatable expression' error. It would be nice to
821 // change this code to emit a better diagnostic.
824 if (ABE->getOpcode() == MCBinaryExpr::Div)
829 case MCBinaryExpr::EQ: Result = LHS == RHS; break;
830 case MCBinaryExpr::GT: Result = LHS > RHS; break;
831 case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
832 case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
833 case MCBinaryExpr::LOr: Result = LHS || RHS; break;
834 case MCBinaryExpr::LShr: Result = uint64_t(LHS) >> uint64_t(RHS); break;
835 case MCBinaryExpr::LT: Result = LHS < RHS; break;
836 case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
837 case MCBinaryExpr::Mul: Result = LHS * RHS; break;
838 case MCBinaryExpr::NE: Result = LHS != RHS; break;
839 case MCBinaryExpr::Or: Result = LHS | RHS; break;
840 case MCBinaryExpr::Shl: Result = uint64_t(LHS) << uint64_t(RHS); break;
841 case MCBinaryExpr::Sub: Result = LHS - RHS; break;
842 case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
847 Res = MCValue::get(Result);
849 case MCBinaryExpr::EQ:
850 case MCBinaryExpr::GT:
851 case MCBinaryExpr::GTE:
852 case MCBinaryExpr::LT:
853 case MCBinaryExpr::LTE:
854 case MCBinaryExpr::NE:
855 // A comparison operator returns a -1 if true and 0 if false.
856 Res = MCValue::get(Result ? -1 : 0);
864 llvm_unreachable("Invalid assembly expression kind!");
867 MCFragment *MCExpr::findAssociatedFragment() const {
870 // We never look through target specific expressions.
871 return cast<MCTargetExpr>(this)->findAssociatedFragment();
874 return MCSymbol::AbsolutePseudoFragment;
877 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
878 const MCSymbol &Sym = SRE->getSymbol();
879 return Sym.getFragment();
883 return cast<MCUnaryExpr>(this)->getSubExpr()->findAssociatedFragment();
886 const MCBinaryExpr *BE = cast<MCBinaryExpr>(this);
887 MCFragment *LHS_F = BE->getLHS()->findAssociatedFragment();
888 MCFragment *RHS_F = BE->getRHS()->findAssociatedFragment();
890 // If either is absolute, return the other.
891 if (LHS_F == MCSymbol::AbsolutePseudoFragment)
893 if (RHS_F == MCSymbol::AbsolutePseudoFragment)
896 // Not always correct, but probably the best we can do without more context.
897 if (BE->getOpcode() == MCBinaryExpr::Sub)
898 return MCSymbol::AbsolutePseudoFragment;
900 // Otherwise, return the first non-null fragment.
901 return LHS_F ? LHS_F : RHS_F;
905 llvm_unreachable("Invalid assembly expression kind!");