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/MCAsmInfo.h"
15 #include "llvm/MC/MCAsmLayout.h"
16 #include "llvm/MC/MCAssembler.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCObjectWriter.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/MC/MCValue.h"
21 #include "llvm/Support/Casting.h"
22 #include "llvm/Support/Compiler.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/raw_ostream.h"
31 #define DEBUG_TYPE "mcexpr"
36 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
38 } // end namespace stats
39 } // end anonymous namespace
41 void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens) const {
44 return cast<MCTargetExpr>(this)->printImpl(OS, MAI);
45 case MCExpr::Constant:
46 OS << cast<MCConstantExpr>(*this).getValue();
49 case MCExpr::SymbolRef: {
50 const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
51 const MCSymbol &Sym = SRE.getSymbol();
52 // Parenthesize names that start with $ so that they don't look like
55 !InParens && !Sym.getName().empty() && Sym.getName()[0] == '$';
63 if (SRE.getKind() != MCSymbolRefExpr::VK_None)
64 SRE.printVariantKind(OS);
70 const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
71 switch (UE.getOpcode()) {
72 case MCUnaryExpr::LNot: OS << '!'; break;
73 case MCUnaryExpr::Minus: OS << '-'; break;
74 case MCUnaryExpr::Not: OS << '~'; break;
75 case MCUnaryExpr::Plus: OS << '+'; break;
77 bool Binary = UE.getSubExpr()->getKind() == MCExpr::Binary;
78 if (Binary) OS << "(";
79 UE.getSubExpr()->print(OS, MAI);
80 if (Binary) OS << ")";
84 case MCExpr::Binary: {
85 const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
87 // Only print parens around the LHS if it is non-trivial.
88 if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
89 BE.getLHS()->print(OS, MAI);
92 BE.getLHS()->print(OS, MAI);
96 switch (BE.getOpcode()) {
97 case MCBinaryExpr::Add:
98 // Print "X-42" instead of "X+-42".
99 if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
100 if (RHSC->getValue() < 0) {
101 OS << RHSC->getValue();
108 case MCBinaryExpr::AShr: OS << ">>"; break;
109 case MCBinaryExpr::And: OS << '&'; break;
110 case MCBinaryExpr::Div: OS << '/'; break;
111 case MCBinaryExpr::EQ: OS << "=="; break;
112 case MCBinaryExpr::GT: OS << '>'; break;
113 case MCBinaryExpr::GTE: OS << ">="; break;
114 case MCBinaryExpr::LAnd: OS << "&&"; break;
115 case MCBinaryExpr::LOr: OS << "||"; break;
116 case MCBinaryExpr::LShr: OS << ">>"; break;
117 case MCBinaryExpr::LT: OS << '<'; break;
118 case MCBinaryExpr::LTE: OS << "<="; break;
119 case MCBinaryExpr::Mod: OS << '%'; break;
120 case MCBinaryExpr::Mul: OS << '*'; break;
121 case MCBinaryExpr::NE: OS << "!="; break;
122 case MCBinaryExpr::Or: OS << '|'; break;
123 case MCBinaryExpr::Shl: OS << "<<"; break;
124 case MCBinaryExpr::Sub: OS << '-'; break;
125 case MCBinaryExpr::Xor: OS << '^'; break;
128 // Only print parens around the LHS if it is non-trivial.
129 if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
130 BE.getRHS()->print(OS, MAI);
133 BE.getRHS()->print(OS, MAI);
140 llvm_unreachable("Invalid expression kind!");
143 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
144 LLVM_DUMP_METHOD void MCExpr::dump() const {
152 const MCBinaryExpr *MCBinaryExpr::create(Opcode Opc, const MCExpr *LHS,
153 const MCExpr *RHS, MCContext &Ctx,
155 return new (Ctx) MCBinaryExpr(Opc, LHS, RHS, Loc);
158 const MCUnaryExpr *MCUnaryExpr::create(Opcode Opc, const MCExpr *Expr,
159 MCContext &Ctx, SMLoc Loc) {
160 return new (Ctx) MCUnaryExpr(Opc, Expr, Loc);
163 const MCConstantExpr *MCConstantExpr::create(int64_t Value, MCContext &Ctx) {
164 return new (Ctx) MCConstantExpr(Value);
169 MCSymbolRefExpr::MCSymbolRefExpr(const MCSymbol *Symbol, VariantKind Kind,
170 const MCAsmInfo *MAI, SMLoc Loc)
171 : MCExpr(MCExpr::SymbolRef, Loc), Kind(Kind),
172 UseParensForSymbolVariant(MAI->useParensForSymbolVariant()),
173 HasSubsectionsViaSymbols(MAI->hasSubsectionsViaSymbols()),
178 const MCSymbolRefExpr *MCSymbolRefExpr::create(const MCSymbol *Sym,
180 MCContext &Ctx, SMLoc Loc) {
181 return new (Ctx) MCSymbolRefExpr(Sym, Kind, Ctx.getAsmInfo(), Loc);
184 const MCSymbolRefExpr *MCSymbolRefExpr::create(StringRef Name, VariantKind Kind,
186 return create(Ctx.getOrCreateSymbol(Name), Kind, Ctx);
189 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
191 case VK_Invalid: return "<<invalid>>";
192 case VK_None: return "<<none>>";
194 case VK_DTPOFF: return "DTPOFF";
195 case VK_DTPREL: return "DTPREL";
196 case VK_GOT: return "GOT";
197 case VK_GOTOFF: return "GOTOFF";
198 case VK_GOTREL: return "GOTREL";
199 case VK_GOTPCREL: return "GOTPCREL";
200 case VK_GOTTPOFF: return "GOTTPOFF";
201 case VK_INDNTPOFF: return "INDNTPOFF";
202 case VK_NTPOFF: return "NTPOFF";
203 case VK_GOTNTPOFF: return "GOTNTPOFF";
204 case VK_PLT: return "PLT";
205 case VK_TLSGD: return "TLSGD";
206 case VK_TLSLD: return "TLSLD";
207 case VK_TLSLDM: return "TLSLDM";
208 case VK_TPOFF: return "TPOFF";
209 case VK_TPREL: return "TPREL";
210 case VK_TLSCALL: return "tlscall";
211 case VK_TLSDESC: return "tlsdesc";
212 case VK_TLVP: return "TLVP";
213 case VK_TLVPPAGE: return "TLVPPAGE";
214 case VK_TLVPPAGEOFF: return "TLVPPAGEOFF";
215 case VK_PAGE: return "PAGE";
216 case VK_PAGEOFF: return "PAGEOFF";
217 case VK_GOTPAGE: return "GOTPAGE";
218 case VK_GOTPAGEOFF: return "GOTPAGEOFF";
219 case VK_SECREL: return "SECREL32";
220 case VK_SIZE: return "SIZE";
221 case VK_WEAKREF: return "WEAKREF";
222 case VK_X86_ABS8: return "ABS8";
223 case VK_ARM_NONE: return "none";
224 case VK_ARM_GOT_PREL: return "GOT_PREL";
225 case VK_ARM_TARGET1: return "target1";
226 case VK_ARM_TARGET2: return "target2";
227 case VK_ARM_PREL31: return "prel31";
228 case VK_ARM_SBREL: return "sbrel";
229 case VK_ARM_TLSLDO: return "tlsldo";
230 case VK_ARM_TLSDESCSEQ: return "tlsdescseq";
231 case VK_AVR_NONE: return "none";
232 case VK_AVR_LO8: return "lo8";
233 case VK_AVR_HI8: return "hi8";
234 case VK_AVR_HLO8: return "hlo8";
235 case VK_AVR_DIFF8: return "diff8";
236 case VK_AVR_DIFF16: return "diff16";
237 case VK_AVR_DIFF32: return "diff32";
238 case VK_PPC_LO: return "l";
239 case VK_PPC_HI: return "h";
240 case VK_PPC_HA: return "ha";
241 case VK_PPC_HIGHER: return "higher";
242 case VK_PPC_HIGHERA: return "highera";
243 case VK_PPC_HIGHEST: return "highest";
244 case VK_PPC_HIGHESTA: return "highesta";
245 case VK_PPC_GOT_LO: return "got@l";
246 case VK_PPC_GOT_HI: return "got@h";
247 case VK_PPC_GOT_HA: return "got@ha";
248 case VK_PPC_TOCBASE: return "tocbase";
249 case VK_PPC_TOC: return "toc";
250 case VK_PPC_TOC_LO: return "toc@l";
251 case VK_PPC_TOC_HI: return "toc@h";
252 case VK_PPC_TOC_HA: return "toc@ha";
253 case VK_PPC_DTPMOD: return "dtpmod";
254 case VK_PPC_TPREL_LO: return "tprel@l";
255 case VK_PPC_TPREL_HI: return "tprel@h";
256 case VK_PPC_TPREL_HA: return "tprel@ha";
257 case VK_PPC_TPREL_HIGHER: return "tprel@higher";
258 case VK_PPC_TPREL_HIGHERA: return "tprel@highera";
259 case VK_PPC_TPREL_HIGHEST: return "tprel@highest";
260 case VK_PPC_TPREL_HIGHESTA: return "tprel@highesta";
261 case VK_PPC_DTPREL_LO: return "dtprel@l";
262 case VK_PPC_DTPREL_HI: return "dtprel@h";
263 case VK_PPC_DTPREL_HA: return "dtprel@ha";
264 case VK_PPC_DTPREL_HIGHER: return "dtprel@higher";
265 case VK_PPC_DTPREL_HIGHERA: return "dtprel@highera";
266 case VK_PPC_DTPREL_HIGHEST: return "dtprel@highest";
267 case VK_PPC_DTPREL_HIGHESTA: return "dtprel@highesta";
268 case VK_PPC_GOT_TPREL: return "got@tprel";
269 case VK_PPC_GOT_TPREL_LO: return "got@tprel@l";
270 case VK_PPC_GOT_TPREL_HI: return "got@tprel@h";
271 case VK_PPC_GOT_TPREL_HA: return "got@tprel@ha";
272 case VK_PPC_GOT_DTPREL: return "got@dtprel";
273 case VK_PPC_GOT_DTPREL_LO: return "got@dtprel@l";
274 case VK_PPC_GOT_DTPREL_HI: return "got@dtprel@h";
275 case VK_PPC_GOT_DTPREL_HA: return "got@dtprel@ha";
276 case VK_PPC_TLS: return "tls";
277 case VK_PPC_GOT_TLSGD: return "got@tlsgd";
278 case VK_PPC_GOT_TLSGD_LO: return "got@tlsgd@l";
279 case VK_PPC_GOT_TLSGD_HI: return "got@tlsgd@h";
280 case VK_PPC_GOT_TLSGD_HA: return "got@tlsgd@ha";
281 case VK_PPC_TLSGD: return "tlsgd";
282 case VK_PPC_GOT_TLSLD: return "got@tlsld";
283 case VK_PPC_GOT_TLSLD_LO: return "got@tlsld@l";
284 case VK_PPC_GOT_TLSLD_HI: return "got@tlsld@h";
285 case VK_PPC_GOT_TLSLD_HA: return "got@tlsld@ha";
286 case VK_PPC_TLSLD: return "tlsld";
287 case VK_PPC_LOCAL: return "local";
288 case VK_COFF_IMGREL32: return "IMGREL";
289 case VK_Hexagon_PCREL: return "PCREL";
290 case VK_Hexagon_LO16: return "LO16";
291 case VK_Hexagon_HI16: return "HI16";
292 case VK_Hexagon_GPREL: return "GPREL";
293 case VK_Hexagon_GD_GOT: return "GDGOT";
294 case VK_Hexagon_LD_GOT: return "LDGOT";
295 case VK_Hexagon_GD_PLT: return "GDPLT";
296 case VK_Hexagon_LD_PLT: return "LDPLT";
297 case VK_Hexagon_IE: return "IE";
298 case VK_Hexagon_IE_GOT: return "IEGOT";
299 case VK_WebAssembly_FUNCTION: return "FUNCTION";
300 case VK_WebAssembly_TYPEINDEX: return "TYPEINDEX";
301 case VK_AMDGPU_GOTPCREL32_LO: return "gotpcrel32@lo";
302 case VK_AMDGPU_GOTPCREL32_HI: return "gotpcrel32@hi";
303 case VK_AMDGPU_REL32_LO: return "rel32@lo";
304 case VK_AMDGPU_REL32_HI: return "rel32@hi";
306 llvm_unreachable("Invalid variant kind");
309 MCSymbolRefExpr::VariantKind
310 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
311 return StringSwitch<VariantKind>(Name.lower())
312 .Case("dtprel", VK_DTPREL)
313 .Case("dtpoff", VK_DTPOFF)
315 .Case("gotoff", VK_GOTOFF)
316 .Case("gotrel", VK_GOTREL)
317 .Case("gotpcrel", VK_GOTPCREL)
318 .Case("gottpoff", VK_GOTTPOFF)
319 .Case("indntpoff", VK_INDNTPOFF)
320 .Case("ntpoff", VK_NTPOFF)
321 .Case("gotntpoff", VK_GOTNTPOFF)
323 .Case("tlscall", VK_TLSCALL)
324 .Case("tlsdesc", VK_TLSDESC)
325 .Case("tlsgd", VK_TLSGD)
326 .Case("tlsld", VK_TLSLD)
327 .Case("tlsldm", VK_TLSLDM)
328 .Case("tpoff", VK_TPOFF)
329 .Case("tprel", VK_TPREL)
330 .Case("tlvp", VK_TLVP)
331 .Case("tlvppage", VK_TLVPPAGE)
332 .Case("tlvppageoff", VK_TLVPPAGEOFF)
333 .Case("page", VK_PAGE)
334 .Case("pageoff", VK_PAGEOFF)
335 .Case("gotpage", VK_GOTPAGE)
336 .Case("gotpageoff", VK_GOTPAGEOFF)
337 .Case("imgrel", VK_COFF_IMGREL32)
338 .Case("secrel32", VK_SECREL)
339 .Case("size", VK_SIZE)
340 .Case("abs8", VK_X86_ABS8)
341 .Case("l", VK_PPC_LO)
342 .Case("h", VK_PPC_HI)
343 .Case("ha", VK_PPC_HA)
344 .Case("higher", VK_PPC_HIGHER)
345 .Case("highera", VK_PPC_HIGHERA)
346 .Case("highest", VK_PPC_HIGHEST)
347 .Case("highesta", VK_PPC_HIGHESTA)
348 .Case("got@l", VK_PPC_GOT_LO)
349 .Case("got@h", VK_PPC_GOT_HI)
350 .Case("got@ha", VK_PPC_GOT_HA)
351 .Case("local", VK_PPC_LOCAL)
352 .Case("tocbase", VK_PPC_TOCBASE)
353 .Case("toc", VK_PPC_TOC)
354 .Case("toc@l", VK_PPC_TOC_LO)
355 .Case("toc@h", VK_PPC_TOC_HI)
356 .Case("toc@ha", VK_PPC_TOC_HA)
357 .Case("tls", VK_PPC_TLS)
358 .Case("dtpmod", VK_PPC_DTPMOD)
359 .Case("tprel@l", VK_PPC_TPREL_LO)
360 .Case("tprel@h", VK_PPC_TPREL_HI)
361 .Case("tprel@ha", VK_PPC_TPREL_HA)
362 .Case("tprel@higher", VK_PPC_TPREL_HIGHER)
363 .Case("tprel@highera", VK_PPC_TPREL_HIGHERA)
364 .Case("tprel@highest", VK_PPC_TPREL_HIGHEST)
365 .Case("tprel@highesta", VK_PPC_TPREL_HIGHESTA)
366 .Case("dtprel@l", VK_PPC_DTPREL_LO)
367 .Case("dtprel@h", VK_PPC_DTPREL_HI)
368 .Case("dtprel@ha", VK_PPC_DTPREL_HA)
369 .Case("dtprel@higher", VK_PPC_DTPREL_HIGHER)
370 .Case("dtprel@highera", VK_PPC_DTPREL_HIGHERA)
371 .Case("dtprel@highest", VK_PPC_DTPREL_HIGHEST)
372 .Case("dtprel@highesta", VK_PPC_DTPREL_HIGHESTA)
373 .Case("got@tprel", VK_PPC_GOT_TPREL)
374 .Case("got@tprel@l", VK_PPC_GOT_TPREL_LO)
375 .Case("got@tprel@h", VK_PPC_GOT_TPREL_HI)
376 .Case("got@tprel@ha", VK_PPC_GOT_TPREL_HA)
377 .Case("got@dtprel", VK_PPC_GOT_DTPREL)
378 .Case("got@dtprel@l", VK_PPC_GOT_DTPREL_LO)
379 .Case("got@dtprel@h", VK_PPC_GOT_DTPREL_HI)
380 .Case("got@dtprel@ha", VK_PPC_GOT_DTPREL_HA)
381 .Case("got@tlsgd", VK_PPC_GOT_TLSGD)
382 .Case("got@tlsgd@l", VK_PPC_GOT_TLSGD_LO)
383 .Case("got@tlsgd@h", VK_PPC_GOT_TLSGD_HI)
384 .Case("got@tlsgd@ha", VK_PPC_GOT_TLSGD_HA)
385 .Case("got@tlsld", VK_PPC_GOT_TLSLD)
386 .Case("got@tlsld@l", VK_PPC_GOT_TLSLD_LO)
387 .Case("got@tlsld@h", VK_PPC_GOT_TLSLD_HI)
388 .Case("got@tlsld@ha", VK_PPC_GOT_TLSLD_HA)
389 .Case("gdgot", VK_Hexagon_GD_GOT)
390 .Case("gdplt", VK_Hexagon_GD_PLT)
391 .Case("iegot", VK_Hexagon_IE_GOT)
392 .Case("ie", VK_Hexagon_IE)
393 .Case("ldgot", VK_Hexagon_LD_GOT)
394 .Case("ldplt", VK_Hexagon_LD_PLT)
395 .Case("pcrel", VK_Hexagon_PCREL)
396 .Case("none", VK_ARM_NONE)
397 .Case("got_prel", VK_ARM_GOT_PREL)
398 .Case("target1", VK_ARM_TARGET1)
399 .Case("target2", VK_ARM_TARGET2)
400 .Case("prel31", VK_ARM_PREL31)
401 .Case("sbrel", VK_ARM_SBREL)
402 .Case("tlsldo", VK_ARM_TLSLDO)
403 .Case("lo8", VK_AVR_LO8)
404 .Case("hi8", VK_AVR_HI8)
405 .Case("hlo8", VK_AVR_HLO8)
406 .Case("function", VK_WebAssembly_FUNCTION)
407 .Case("typeindex", VK_WebAssembly_TYPEINDEX)
408 .Case("gotpcrel32@lo", VK_AMDGPU_GOTPCREL32_LO)
409 .Case("gotpcrel32@hi", VK_AMDGPU_GOTPCREL32_HI)
410 .Case("rel32@lo", VK_AMDGPU_REL32_LO)
411 .Case("rel32@hi", VK_AMDGPU_REL32_HI)
412 .Default(VK_Invalid);
415 void MCSymbolRefExpr::printVariantKind(raw_ostream &OS) const {
416 if (UseParensForSymbolVariant)
417 OS << '(' << MCSymbolRefExpr::getVariantKindName(getKind()) << ')';
419 OS << '@' << MCSymbolRefExpr::getVariantKindName(getKind());
424 void MCTargetExpr::anchor() {}
428 bool MCExpr::evaluateAsAbsolute(int64_t &Res) const {
429 return evaluateAsAbsolute(Res, nullptr, nullptr, nullptr);
432 bool MCExpr::evaluateAsAbsolute(int64_t &Res,
433 const MCAsmLayout &Layout) const {
434 return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr);
437 bool MCExpr::evaluateAsAbsolute(int64_t &Res,
438 const MCAsmLayout &Layout,
439 const SectionAddrMap &Addrs) const {
440 return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs);
443 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
444 return evaluateAsAbsolute(Res, &Asm, nullptr, nullptr);
447 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm) const {
448 return evaluateAsAbsolute(Res, Asm, nullptr, nullptr);
451 bool MCExpr::evaluateKnownAbsolute(int64_t &Res,
452 const MCAsmLayout &Layout) const {
453 return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr,
457 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
458 const MCAsmLayout *Layout,
459 const SectionAddrMap *Addrs) const {
460 // FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us
461 // absolutize differences across sections and that is what the MachO writer
463 return evaluateAsAbsolute(Res, Asm, Layout, Addrs, Addrs);
466 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
467 const MCAsmLayout *Layout,
468 const SectionAddrMap *Addrs, bool InSet) const {
471 // Fast path constants.
472 if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
473 Res = CE->getValue();
478 evaluateAsRelocatableImpl(Value, Asm, Layout, nullptr, Addrs, InSet);
480 // Record the current value.
481 Res = Value.getConstant();
483 return IsRelocatable && Value.isAbsolute();
486 /// Helper method for \see EvaluateSymbolAdd().
487 static void AttemptToFoldSymbolOffsetDifference(
488 const MCAssembler *Asm, const MCAsmLayout *Layout,
489 const SectionAddrMap *Addrs, bool InSet, const MCSymbolRefExpr *&A,
490 const MCSymbolRefExpr *&B, int64_t &Addend) {
494 const MCSymbol &SA = A->getSymbol();
495 const MCSymbol &SB = B->getSymbol();
497 if (SA.isUndefined() || SB.isUndefined())
500 if (!Asm->getWriter().isSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
503 if (SA.getFragment() == SB.getFragment() && !SA.isVariable() &&
504 !SA.isUnset() && !SB.isVariable() && !SB.isUnset()) {
505 Addend += (SA.getOffset() - SB.getOffset());
507 // Pointers to Thumb symbols need to have their low-bit set to allow
509 if (Asm->isThumbFunc(&SA))
512 // Clear the symbol expr pointers to indicate we have folded these
521 const MCSection &SecA = *SA.getFragment()->getParent();
522 const MCSection &SecB = *SB.getFragment()->getParent();
524 if ((&SecA != &SecB) && !Addrs)
528 Addend += Layout->getSymbolOffset(A->getSymbol()) -
529 Layout->getSymbolOffset(B->getSymbol());
530 if (Addrs && (&SecA != &SecB))
531 Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
533 // Pointers to Thumb symbols need to have their low-bit set to allow
535 if (Asm->isThumbFunc(&SA))
538 // Clear the symbol expr pointers to indicate we have folded these
543 /// Evaluate the result of an add between (conceptually) two MCValues.
545 /// This routine conceptually attempts to construct an MCValue:
546 /// Result = (Result_A - Result_B + Result_Cst)
547 /// from two MCValue's LHS and RHS where
548 /// Result = LHS + RHS
550 /// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
552 /// This routine attempts to aggresively fold the operands such that the result
553 /// is representable in an MCValue, but may not always succeed.
555 /// \returns True on success, false if the result is not representable in an
558 /// NOTE: It is really important to have both the Asm and Layout arguments.
559 /// They might look redundant, but this function can be used before layout
560 /// is done (see the object streamer for example) and having the Asm argument
561 /// lets us avoid relaxations early.
563 EvaluateSymbolicAdd(const MCAssembler *Asm, const MCAsmLayout *Layout,
564 const SectionAddrMap *Addrs, bool InSet, const MCValue &LHS,
565 const MCSymbolRefExpr *RHS_A, const MCSymbolRefExpr *RHS_B,
566 int64_t RHS_Cst, MCValue &Res) {
567 // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy
568 // about dealing with modifiers. This will ultimately bite us, one day.
569 const MCSymbolRefExpr *LHS_A = LHS.getSymA();
570 const MCSymbolRefExpr *LHS_B = LHS.getSymB();
571 int64_t LHS_Cst = LHS.getConstant();
573 // Fold the result constant immediately.
574 int64_t Result_Cst = LHS_Cst + RHS_Cst;
576 assert((!Layout || Asm) &&
577 "Must have an assembler object if layout is given!");
579 // If we have a layout, we can fold resolved differences.
581 // First, fold out any differences which are fully resolved. By
582 // reassociating terms in
583 // Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
584 // we have the four possible differences:
589 // Since we are attempting to be as aggressive as possible about folding, we
590 // attempt to evaluate each possible alternative.
591 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
593 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
595 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
597 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
601 // We can't represent the addition or subtraction of two symbols.
602 if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
605 // At this point, we have at most one additive symbol and one subtractive
606 // symbol -- find them.
607 const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
608 const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;
610 Res = MCValue::get(A, B, Result_Cst);
614 bool MCExpr::evaluateAsRelocatable(MCValue &Res,
615 const MCAsmLayout *Layout,
616 const MCFixup *Fixup) const {
617 MCAssembler *Assembler = Layout ? &Layout->getAssembler() : nullptr;
618 return evaluateAsRelocatableImpl(Res, Assembler, Layout, Fixup, nullptr,
622 bool MCExpr::evaluateAsValue(MCValue &Res, const MCAsmLayout &Layout) const {
623 MCAssembler *Assembler = &Layout.getAssembler();
624 return evaluateAsRelocatableImpl(Res, Assembler, &Layout, nullptr, nullptr,
628 static bool canExpand(const MCSymbol &Sym, bool InSet) {
629 const MCExpr *Expr = Sym.getVariableValue();
630 const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr);
632 if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF)
638 return !Sym.isInSection();
641 bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
642 const MCAsmLayout *Layout,
643 const MCFixup *Fixup,
644 const SectionAddrMap *Addrs,
646 ++stats::MCExprEvaluate;
650 return cast<MCTargetExpr>(this)->evaluateAsRelocatableImpl(Res, Layout,
654 Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
658 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
659 const MCSymbol &Sym = SRE->getSymbol();
661 // Evaluate recursively if this is a variable.
662 if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None &&
663 canExpand(Sym, InSet)) {
664 bool IsMachO = SRE->hasSubsectionsViaSymbols();
665 if (Sym.getVariableValue()->evaluateAsRelocatableImpl(
666 Res, Asm, Layout, Fixup, Addrs, InSet || IsMachO)) {
670 const MCSymbolRefExpr *A = Res.getSymA();
671 const MCSymbolRefExpr *B = Res.getSymB();
672 // FIXME: This is small hack. Given
675 // the OS X assembler will completely drop the 4. We should probably
676 // include it in the relocation or produce an error if that is not
678 // Allow constant expressions.
681 // Allows aliases with zero offset.
682 if (Res.getConstant() == 0 && (!A || !B))
687 Res = MCValue::get(SRE, nullptr, 0);
692 const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
695 if (!AUE->getSubExpr()->evaluateAsRelocatableImpl(Value, Asm, Layout, Fixup,
699 switch (AUE->getOpcode()) {
700 case MCUnaryExpr::LNot:
701 if (!Value.isAbsolute())
703 Res = MCValue::get(!Value.getConstant());
705 case MCUnaryExpr::Minus:
706 /// -(a - b + const) ==> (b - a - const)
707 if (Value.getSymA() && !Value.getSymB())
710 // The cast avoids undefined behavior if the constant is INT64_MIN.
711 Res = MCValue::get(Value.getSymB(), Value.getSymA(),
712 -(uint64_t)Value.getConstant());
714 case MCUnaryExpr::Not:
715 if (!Value.isAbsolute())
717 Res = MCValue::get(~Value.getConstant());
719 case MCUnaryExpr::Plus:
728 const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
729 MCValue LHSValue, RHSValue;
731 if (!ABE->getLHS()->evaluateAsRelocatableImpl(LHSValue, Asm, Layout, Fixup,
733 !ABE->getRHS()->evaluateAsRelocatableImpl(RHSValue, Asm, Layout, Fixup,
737 // We only support a few operations on non-constant expressions, handle
739 if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
740 switch (ABE->getOpcode()) {
743 case MCBinaryExpr::Sub:
744 // Negate RHS and add.
745 // The cast avoids undefined behavior if the constant is INT64_MIN.
746 return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
747 RHSValue.getSymB(), RHSValue.getSymA(),
748 -(uint64_t)RHSValue.getConstant(), Res);
750 case MCBinaryExpr::Add:
751 return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
752 RHSValue.getSymA(), RHSValue.getSymB(),
753 RHSValue.getConstant(), Res);
757 // FIXME: We need target hooks for the evaluation. It may be limited in
758 // width, and gas defines the result of comparisons differently from
760 int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
762 auto Op = ABE->getOpcode();
764 case MCBinaryExpr::AShr: Result = LHS >> RHS; break;
765 case MCBinaryExpr::Add: Result = LHS + RHS; break;
766 case MCBinaryExpr::And: Result = LHS & RHS; break;
767 case MCBinaryExpr::Div:
768 case MCBinaryExpr::Mod:
769 // Handle division by zero. gas just emits a warning and keeps going,
770 // we try to be stricter.
771 // FIXME: Currently the caller of this function has no way to understand
772 // we're bailing out because of 'division by zero'. Therefore, it will
773 // emit a 'expected relocatable expression' error. It would be nice to
774 // change this code to emit a better diagnostic.
777 if (ABE->getOpcode() == MCBinaryExpr::Div)
782 case MCBinaryExpr::EQ: Result = LHS == RHS; break;
783 case MCBinaryExpr::GT: Result = LHS > RHS; break;
784 case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
785 case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
786 case MCBinaryExpr::LOr: Result = LHS || RHS; break;
787 case MCBinaryExpr::LShr: Result = uint64_t(LHS) >> uint64_t(RHS); break;
788 case MCBinaryExpr::LT: Result = LHS < RHS; break;
789 case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
790 case MCBinaryExpr::Mul: Result = LHS * RHS; break;
791 case MCBinaryExpr::NE: Result = LHS != RHS; break;
792 case MCBinaryExpr::Or: Result = LHS | RHS; break;
793 case MCBinaryExpr::Shl: Result = uint64_t(LHS) << uint64_t(RHS); break;
794 case MCBinaryExpr::Sub: Result = LHS - RHS; break;
795 case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
800 Res = MCValue::get(Result);
802 case MCBinaryExpr::EQ:
803 case MCBinaryExpr::GT:
804 case MCBinaryExpr::GTE:
805 case MCBinaryExpr::LT:
806 case MCBinaryExpr::LTE:
807 case MCBinaryExpr::NE:
808 // A comparison operator returns a -1 if true and 0 if false.
809 Res = MCValue::get(Result ? -1 : 0);
817 llvm_unreachable("Invalid assembly expression kind!");
820 MCFragment *MCExpr::findAssociatedFragment() const {
823 // We never look through target specific expressions.
824 return cast<MCTargetExpr>(this)->findAssociatedFragment();
827 return MCSymbol::AbsolutePseudoFragment;
830 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
831 const MCSymbol &Sym = SRE->getSymbol();
832 return Sym.getFragment();
836 return cast<MCUnaryExpr>(this)->getSubExpr()->findAssociatedFragment();
839 const MCBinaryExpr *BE = cast<MCBinaryExpr>(this);
840 MCFragment *LHS_F = BE->getLHS()->findAssociatedFragment();
841 MCFragment *RHS_F = BE->getRHS()->findAssociatedFragment();
843 // If either is absolute, return the other.
844 if (LHS_F == MCSymbol::AbsolutePseudoFragment)
846 if (RHS_F == MCSymbol::AbsolutePseudoFragment)
849 // Not always correct, but probably the best we can do without more context.
850 if (BE->getOpcode() == MCBinaryExpr::Sub)
851 return MCSymbol::AbsolutePseudoFragment;
853 // Otherwise, return the first non-null fragment.
854 return LHS_F ? LHS_F : RHS_F;
858 llvm_unreachable("Invalid assembly expression kind!");