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/MC/MCAsmInfo.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"
25
#define DEBUG_TYPE "mcexpr"
29
STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
33
void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
36
return cast<MCTargetExpr>(this)->printImpl(OS, MAI);
37
case MCExpr::Constant:
38
OS << cast<MCConstantExpr>(*this).getValue();
41
case MCExpr::SymbolRef: {
42
const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
43
const MCSymbol &Sym = SRE.getSymbol();
44
// Parenthesize names that start with $ so that they don't look like
46
bool UseParens = Sym.getName()[0] == '$';
54
if (SRE.getKind() != MCSymbolRefExpr::VK_None)
55
SRE.printVariantKind(OS);
61
const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
62
switch (UE.getOpcode()) {
63
case MCUnaryExpr::LNot: OS << '!'; break;
64
case MCUnaryExpr::Minus: OS << '-'; break;
65
case MCUnaryExpr::Not: OS << '~'; break;
66
case MCUnaryExpr::Plus: OS << '+'; break;
68
UE.getSubExpr()->print(OS, MAI);
72
case MCExpr::Binary: {
73
const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
75
// Only print parens around the LHS if it is non-trivial.
76
if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
77
BE.getLHS()->print(OS, MAI);
80
BE.getLHS()->print(OS, MAI);
84
switch (BE.getOpcode()) {
85
case MCBinaryExpr::Add:
86
// Print "X-42" instead of "X+-42".
87
if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
88
if (RHSC->getValue() < 0) {
89
OS << RHSC->getValue();
96
case MCBinaryExpr::AShr: OS << ">>"; break;
97
case MCBinaryExpr::And: OS << '&'; break;
98
case MCBinaryExpr::Div: OS << '/'; break;
99
case MCBinaryExpr::EQ: OS << "=="; break;
100
case MCBinaryExpr::GT: OS << '>'; break;
101
case MCBinaryExpr::GTE: OS << ">="; break;
102
case MCBinaryExpr::LAnd: OS << "&&"; break;
103
case MCBinaryExpr::LOr: OS << "||"; break;
104
case MCBinaryExpr::LShr: OS << ">>"; break;
105
case MCBinaryExpr::LT: OS << '<'; break;
106
case MCBinaryExpr::LTE: OS << "<="; break;
107
case MCBinaryExpr::Mod: OS << '%'; break;
108
case MCBinaryExpr::Mul: OS << '*'; break;
109
case MCBinaryExpr::NE: OS << "!="; break;
110
case MCBinaryExpr::Or: OS << '|'; break;
111
case MCBinaryExpr::Shl: OS << "<<"; break;
112
case MCBinaryExpr::Sub: OS << '-'; break;
113
case MCBinaryExpr::Xor: OS << '^'; break;
116
// Only print parens around the LHS if it is non-trivial.
117
if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
118
BE.getRHS()->print(OS, MAI);
121
BE.getRHS()->print(OS, MAI);
128
llvm_unreachable("Invalid expression kind!");
131
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
132
void MCExpr::dump() const {
140
const MCBinaryExpr *MCBinaryExpr::create(Opcode Opc, const MCExpr *LHS,
141
const MCExpr *RHS, MCContext &Ctx) {
142
return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
145
const MCUnaryExpr *MCUnaryExpr::create(Opcode Opc, const MCExpr *Expr,
147
return new (Ctx) MCUnaryExpr(Opc, Expr);
150
const MCConstantExpr *MCConstantExpr::create(int64_t Value, MCContext &Ctx) {
151
return new (Ctx) MCConstantExpr(Value);
156
MCSymbolRefExpr::MCSymbolRefExpr(const MCSymbol *Symbol, VariantKind Kind,
157
const MCAsmInfo *MAI)
158
: MCExpr(MCExpr::SymbolRef), Kind(Kind),
159
UseParensForSymbolVariant(MAI->useParensForSymbolVariant()),
160
HasSubsectionsViaSymbols(MAI->hasSubsectionsViaSymbols()),
165
const MCSymbolRefExpr *MCSymbolRefExpr::create(const MCSymbol *Sym,
168
return new (Ctx) MCSymbolRefExpr(Sym, Kind, Ctx.getAsmInfo());
171
const MCSymbolRefExpr *MCSymbolRefExpr::create(StringRef Name, VariantKind Kind,
173
return create(Ctx.getOrCreateSymbol(Name), Kind, Ctx);
176
StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
178
case VK_Invalid: return "<<invalid>>";
179
case VK_None: return "<<none>>";
181
case VK_GOT: return "GOT";
182
case VK_GOTOFF: return "GOTOFF";
183
case VK_GOTPCREL: return "GOTPCREL";
184
case VK_GOTTPOFF: return "GOTTPOFF";
185
case VK_INDNTPOFF: return "INDNTPOFF";
186
case VK_NTPOFF: return "NTPOFF";
187
case VK_GOTNTPOFF: return "GOTNTPOFF";
188
case VK_PLT: return "PLT";
189
case VK_TLSGD: return "TLSGD";
190
case VK_TLSLD: return "TLSLD";
191
case VK_TLSLDM: return "TLSLDM";
192
case VK_TPOFF: return "TPOFF";
193
case VK_DTPOFF: return "DTPOFF";
194
case VK_TLVP: return "TLVP";
195
case VK_TLVPPAGE: return "TLVPPAGE";
196
case VK_TLVPPAGEOFF: return "TLVPPAGEOFF";
197
case VK_PAGE: return "PAGE";
198
case VK_PAGEOFF: return "PAGEOFF";
199
case VK_GOTPAGE: return "GOTPAGE";
200
case VK_GOTPAGEOFF: return "GOTPAGEOFF";
201
case VK_SECREL: return "SECREL32";
202
case VK_SIZE: return "SIZE";
203
case VK_WEAKREF: return "WEAKREF";
204
case VK_ARM_NONE: return "none";
205
case VK_ARM_TARGET1: return "target1";
206
case VK_ARM_TARGET2: return "target2";
207
case VK_ARM_PREL31: return "prel31";
208
case VK_ARM_SBREL: return "sbrel";
209
case VK_ARM_TLSLDO: return "tlsldo";
210
case VK_ARM_TLSCALL: return "tlscall";
211
case VK_ARM_TLSDESC: return "tlsdesc";
212
case VK_ARM_TLSDESCSEQ: return "tlsdescseq";
213
case VK_PPC_LO: return "l";
214
case VK_PPC_HI: return "h";
215
case VK_PPC_HA: return "ha";
216
case VK_PPC_HIGHER: return "higher";
217
case VK_PPC_HIGHERA: return "highera";
218
case VK_PPC_HIGHEST: return "highest";
219
case VK_PPC_HIGHESTA: return "highesta";
220
case VK_PPC_GOT_LO: return "got@l";
221
case VK_PPC_GOT_HI: return "got@h";
222
case VK_PPC_GOT_HA: return "got@ha";
223
case VK_PPC_TOCBASE: return "tocbase";
224
case VK_PPC_TOC: return "toc";
225
case VK_PPC_TOC_LO: return "toc@l";
226
case VK_PPC_TOC_HI: return "toc@h";
227
case VK_PPC_TOC_HA: return "toc@ha";
228
case VK_PPC_DTPMOD: return "dtpmod";
229
case VK_PPC_TPREL: return "tprel";
230
case VK_PPC_TPREL_LO: return "tprel@l";
231
case VK_PPC_TPREL_HI: return "tprel@h";
232
case VK_PPC_TPREL_HA: return "tprel@ha";
233
case VK_PPC_TPREL_HIGHER: return "tprel@higher";
234
case VK_PPC_TPREL_HIGHERA: return "tprel@highera";
235
case VK_PPC_TPREL_HIGHEST: return "tprel@highest";
236
case VK_PPC_TPREL_HIGHESTA: return "tprel@highesta";
237
case VK_PPC_DTPREL: return "dtprel";
238
case VK_PPC_DTPREL_LO: return "dtprel@l";
239
case VK_PPC_DTPREL_HI: return "dtprel@h";
240
case VK_PPC_DTPREL_HA: return "dtprel@ha";
241
case VK_PPC_DTPREL_HIGHER: return "dtprel@higher";
242
case VK_PPC_DTPREL_HIGHERA: return "dtprel@highera";
243
case VK_PPC_DTPREL_HIGHEST: return "dtprel@highest";
244
case VK_PPC_DTPREL_HIGHESTA: return "dtprel@highesta";
245
case VK_PPC_GOT_TPREL: return "got@tprel";
246
case VK_PPC_GOT_TPREL_LO: return "got@tprel@l";
247
case VK_PPC_GOT_TPREL_HI: return "got@tprel@h";
248
case VK_PPC_GOT_TPREL_HA: return "got@tprel@ha";
249
case VK_PPC_GOT_DTPREL: return "got@dtprel";
250
case VK_PPC_GOT_DTPREL_LO: return "got@dtprel@l";
251
case VK_PPC_GOT_DTPREL_HI: return "got@dtprel@h";
252
case VK_PPC_GOT_DTPREL_HA: return "got@dtprel@ha";
253
case VK_PPC_TLS: return "tls";
254
case VK_PPC_GOT_TLSGD: return "got@tlsgd";
255
case VK_PPC_GOT_TLSGD_LO: return "got@tlsgd@l";
256
case VK_PPC_GOT_TLSGD_HI: return "got@tlsgd@h";
257
case VK_PPC_GOT_TLSGD_HA: return "got@tlsgd@ha";
258
case VK_PPC_TLSGD: return "tlsgd";
259
case VK_PPC_GOT_TLSLD: return "got@tlsld";
260
case VK_PPC_GOT_TLSLD_LO: return "got@tlsld@l";
261
case VK_PPC_GOT_TLSLD_HI: return "got@tlsld@h";
262
case VK_PPC_GOT_TLSLD_HA: return "got@tlsld@ha";
263
case VK_PPC_TLSLD: return "tlsld";
264
case VK_PPC_LOCAL: return "local";
265
case VK_Mips_GPREL: return "GPREL";
266
case VK_Mips_GOT_CALL: return "GOT_CALL";
267
case VK_Mips_GOT16: return "GOT16";
268
case VK_Mips_GOT: return "GOT";
269
case VK_Mips_ABS_HI: return "ABS_HI";
270
case VK_Mips_ABS_LO: return "ABS_LO";
271
case VK_Mips_TLSGD: return "TLSGD";
272
case VK_Mips_TLSLDM: return "TLSLDM";
273
case VK_Mips_DTPREL_HI: return "DTPREL_HI";
274
case VK_Mips_DTPREL_LO: return "DTPREL_LO";
275
case VK_Mips_GOTTPREL: return "GOTTPREL";
276
case VK_Mips_TPREL_HI: return "TPREL_HI";
277
case VK_Mips_TPREL_LO: return "TPREL_LO";
278
case VK_Mips_GPOFF_HI: return "GPOFF_HI";
279
case VK_Mips_GPOFF_LO: return "GPOFF_LO";
280
case VK_Mips_GOT_DISP: return "GOT_DISP";
281
case VK_Mips_GOT_PAGE: return "GOT_PAGE";
282
case VK_Mips_GOT_OFST: return "GOT_OFST";
283
case VK_Mips_HIGHER: return "HIGHER";
284
case VK_Mips_HIGHEST: return "HIGHEST";
285
case VK_Mips_GOT_HI16: return "GOT_HI16";
286
case VK_Mips_GOT_LO16: return "GOT_LO16";
287
case VK_Mips_CALL_HI16: return "CALL_HI16";
288
case VK_Mips_CALL_LO16: return "CALL_LO16";
289
case VK_Mips_PCREL_HI16: return "PCREL_HI16";
290
case VK_Mips_PCREL_LO16: return "PCREL_LO16";
291
case VK_COFF_IMGREL32: return "IMGREL";
292
case VK_Hexagon_PCREL: return "PCREL";
293
case VK_Hexagon_LO16: return "LO16";
294
case VK_Hexagon_HI16: return "HI16";
295
case VK_Hexagon_GPREL: return "GPREL";
296
case VK_Hexagon_GD_GOT: return "GDGOT";
297
case VK_Hexagon_LD_GOT: return "LDGOT";
298
case VK_Hexagon_GD_PLT: return "GDPLT";
299
case VK_Hexagon_LD_PLT: return "LDPLT";
300
case VK_Hexagon_IE: return "IE";
301
case VK_Hexagon_IE_GOT: return "IEGOT";
302
case VK_TPREL: return "tprel";
303
case VK_DTPREL: return "dtprel";
305
llvm_unreachable("Invalid variant kind");
308
MCSymbolRefExpr::VariantKind
309
MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
310
return StringSwitch<VariantKind>(Name.lower())
312
.Case("gotoff", VK_GOTOFF)
313
.Case("gotpcrel", VK_GOTPCREL)
314
.Case("got_prel", VK_GOTPCREL)
315
.Case("gottpoff", VK_GOTTPOFF)
316
.Case("indntpoff", VK_INDNTPOFF)
317
.Case("ntpoff", VK_NTPOFF)
318
.Case("gotntpoff", VK_GOTNTPOFF)
320
.Case("tlsgd", VK_TLSGD)
321
.Case("tlsld", VK_TLSLD)
322
.Case("tlsldm", VK_TLSLDM)
323
.Case("tpoff", VK_TPOFF)
324
.Case("dtpoff", VK_DTPOFF)
325
.Case("tlvp", VK_TLVP)
326
.Case("tlvppage", VK_TLVPPAGE)
327
.Case("tlvppageoff", VK_TLVPPAGEOFF)
328
.Case("page", VK_PAGE)
329
.Case("pageoff", VK_PAGEOFF)
330
.Case("gotpage", VK_GOTPAGE)
331
.Case("gotpageoff", VK_GOTPAGEOFF)
332
.Case("imgrel", VK_COFF_IMGREL32)
333
.Case("secrel32", VK_SECREL)
334
.Case("size", VK_SIZE)
335
.Case("l", VK_PPC_LO)
336
.Case("h", VK_PPC_HI)
337
.Case("ha", VK_PPC_HA)
338
.Case("higher", VK_PPC_HIGHER)
339
.Case("highera", VK_PPC_HIGHERA)
340
.Case("highest", VK_PPC_HIGHEST)
341
.Case("highesta", VK_PPC_HIGHESTA)
342
.Case("got@l", VK_PPC_GOT_LO)
343
.Case("got@h", VK_PPC_GOT_HI)
344
.Case("got@ha", VK_PPC_GOT_HA)
345
.Case("local", VK_PPC_LOCAL)
346
.Case("tocbase", VK_PPC_TOCBASE)
347
.Case("toc", VK_PPC_TOC)
348
.Case("toc@l", VK_PPC_TOC_LO)
349
.Case("toc@h", VK_PPC_TOC_HI)
350
.Case("toc@ha", VK_PPC_TOC_HA)
351
.Case("tls", VK_PPC_TLS)
352
.Case("dtpmod", VK_PPC_DTPMOD)
353
.Case("tprel", VK_PPC_TPREL)
354
.Case("tprel@l", VK_PPC_TPREL_LO)
355
.Case("tprel@h", VK_PPC_TPREL_HI)
356
.Case("tprel@ha", VK_PPC_TPREL_HA)
357
.Case("tprel@higher", VK_PPC_TPREL_HIGHER)
358
.Case("tprel@highera", VK_PPC_TPREL_HIGHERA)
359
.Case("tprel@highest", VK_PPC_TPREL_HIGHEST)
360
.Case("tprel@highesta", VK_PPC_TPREL_HIGHESTA)
361
.Case("dtprel", VK_PPC_DTPREL)
362
.Case("dtprel@l", VK_PPC_DTPREL_LO)
363
.Case("dtprel@h", VK_PPC_DTPREL_HI)
364
.Case("dtprel@ha", VK_PPC_DTPREL_HA)
365
.Case("dtprel@higher", VK_PPC_DTPREL_HIGHER)
366
.Case("dtprel@highera", VK_PPC_DTPREL_HIGHERA)
367
.Case("dtprel@highest", VK_PPC_DTPREL_HIGHEST)
368
.Case("dtprel@highesta", VK_PPC_DTPREL_HIGHESTA)
369
.Case("got@tprel", VK_PPC_GOT_TPREL)
370
.Case("got@tprel@l", VK_PPC_GOT_TPREL_LO)
371
.Case("got@tprel@h", VK_PPC_GOT_TPREL_HI)
372
.Case("got@tprel@ha", VK_PPC_GOT_TPREL_HA)
373
.Case("got@dtprel", VK_PPC_GOT_DTPREL)
374
.Case("got@dtprel@l", VK_PPC_GOT_DTPREL_LO)
375
.Case("got@dtprel@h", VK_PPC_GOT_DTPREL_HI)
376
.Case("got@dtprel@ha", VK_PPC_GOT_DTPREL_HA)
377
.Case("got@tlsgd", VK_PPC_GOT_TLSGD)
378
.Case("got@tlsgd@l", VK_PPC_GOT_TLSGD_LO)
379
.Case("got@tlsgd@h", VK_PPC_GOT_TLSGD_HI)
380
.Case("got@tlsgd@ha", VK_PPC_GOT_TLSGD_HA)
381
.Case("got@tlsld", VK_PPC_GOT_TLSLD)
382
.Case("got@tlsld@l", VK_PPC_GOT_TLSLD_LO)
383
.Case("got@tlsld@h", VK_PPC_GOT_TLSLD_HI)
384
.Case("got@tlsld@ha", VK_PPC_GOT_TLSLD_HA)
385
.Case("none", VK_ARM_NONE)
386
.Case("target1", VK_ARM_TARGET1)
387
.Case("target2", VK_ARM_TARGET2)
388
.Case("prel31", VK_ARM_PREL31)
389
.Case("sbrel", VK_ARM_SBREL)
390
.Case("tlsldo", VK_ARM_TLSLDO)
391
.Case("tlscall", VK_ARM_TLSCALL)
392
.Case("tlsdesc", VK_ARM_TLSDESC)
393
.Default(VK_Invalid);
396
void MCSymbolRefExpr::printVariantKind(raw_ostream &OS) const {
397
if (UseParensForSymbolVariant)
398
OS << '(' << MCSymbolRefExpr::getVariantKindName(getKind()) << ')';
400
OS << '@' << MCSymbolRefExpr::getVariantKindName(getKind());
405
void MCTargetExpr::anchor() {}
409
bool MCExpr::evaluateAsAbsolute(int64_t &Res) const {
410
return evaluateAsAbsolute(Res, nullptr, nullptr, nullptr);
413
bool MCExpr::evaluateAsAbsolute(int64_t &Res,
414
const MCAsmLayout &Layout) const {
415
return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr);
418
bool MCExpr::evaluateAsAbsolute(int64_t &Res,
419
const MCAsmLayout &Layout,
420
const SectionAddrMap &Addrs) const {
421
return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs);
424
bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
425
return evaluateAsAbsolute(Res, &Asm, nullptr, nullptr);
428
bool MCExpr::evaluateKnownAbsolute(int64_t &Res,
429
const MCAsmLayout &Layout) const {
430
return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr,
434
bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
435
const MCAsmLayout *Layout,
436
const SectionAddrMap *Addrs) const {
437
// FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us
438
// absolutize differences across sections and that is what the MachO writer
440
return evaluateAsAbsolute(Res, Asm, Layout, Addrs, Addrs);
443
bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
444
const MCAsmLayout *Layout,
445
const SectionAddrMap *Addrs, bool InSet) const {
448
// Fast path constants.
449
if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
450
Res = CE->getValue();
455
evaluateAsRelocatableImpl(Value, Asm, Layout, nullptr, Addrs, InSet);
457
// Record the current value.
458
Res = Value.getConstant();
460
return IsRelocatable && Value.isAbsolute();
463
/// \brief Helper method for \see EvaluateSymbolAdd().
464
static void AttemptToFoldSymbolOffsetDifference(
465
const MCAssembler *Asm, const MCAsmLayout *Layout,
466
const SectionAddrMap *Addrs, bool InSet, const MCSymbolRefExpr *&A,
467
const MCSymbolRefExpr *&B, int64_t &Addend) {
471
const MCSymbol &SA = A->getSymbol();
472
const MCSymbol &SB = B->getSymbol();
474
if (SA.isUndefined() || SB.isUndefined())
477
if (!Asm->getWriter().isSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
480
if (SA.getFragment() == SB.getFragment()) {
481
Addend += (SA.getOffset() - SB.getOffset());
483
// Pointers to Thumb symbols need to have their low-bit set to allow
485
if (Asm->isThumbFunc(&SA))
488
// Clear the symbol expr pointers to indicate we have folded these
497
const MCSection &SecA = *SA.getFragment()->getParent();
498
const MCSection &SecB = *SB.getFragment()->getParent();
500
if ((&SecA != &SecB) && !Addrs)
504
Addend += Layout->getSymbolOffset(A->getSymbol()) -
505
Layout->getSymbolOffset(B->getSymbol());
506
if (Addrs && (&SecA != &SecB))
507
Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
509
// Pointers to Thumb symbols need to have their low-bit set to allow
511
if (Asm->isThumbFunc(&SA))
514
// Clear the symbol expr pointers to indicate we have folded these
519
/// \brief Evaluate the result of an add between (conceptually) two MCValues.
521
/// This routine conceptually attempts to construct an MCValue:
522
/// Result = (Result_A - Result_B + Result_Cst)
523
/// from two MCValue's LHS and RHS where
524
/// Result = LHS + RHS
526
/// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
528
/// This routine attempts to aggresively fold the operands such that the result
529
/// is representable in an MCValue, but may not always succeed.
531
/// \returns True on success, false if the result is not representable in an
534
/// NOTE: It is really important to have both the Asm and Layout arguments.
535
/// They might look redundant, but this function can be used before layout
536
/// is done (see the object streamer for example) and having the Asm argument
537
/// lets us avoid relaxations early.
539
EvaluateSymbolicAdd(const MCAssembler *Asm, const MCAsmLayout *Layout,
540
const SectionAddrMap *Addrs, bool InSet, const MCValue &LHS,
541
const MCSymbolRefExpr *RHS_A, const MCSymbolRefExpr *RHS_B,
542
int64_t RHS_Cst, MCValue &Res) {
543
// FIXME: This routine (and other evaluation parts) are *incredibly* sloppy
544
// about dealing with modifiers. This will ultimately bite us, one day.
545
const MCSymbolRefExpr *LHS_A = LHS.getSymA();
546
const MCSymbolRefExpr *LHS_B = LHS.getSymB();
547
int64_t LHS_Cst = LHS.getConstant();
549
// Fold the result constant immediately.
550
int64_t Result_Cst = LHS_Cst + RHS_Cst;
552
assert((!Layout || Asm) &&
553
"Must have an assembler object if layout is given!");
555
// If we have a layout, we can fold resolved differences.
557
// First, fold out any differences which are fully resolved. By
558
// reassociating terms in
559
// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
560
// we have the four possible differences:
565
// Since we are attempting to be as aggressive as possible about folding, we
566
// attempt to evaluate each possible alternative.
567
AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
569
AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
571
AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
573
AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
577
// We can't represent the addition or subtraction of two symbols.
578
if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
581
// At this point, we have at most one additive symbol and one subtractive
582
// symbol -- find them.
583
const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
584
const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;
586
// If we have a negated symbol, then we must have also have a non-negated
587
// symbol in order to encode the expression.
591
Res = MCValue::get(A, B, Result_Cst);
595
bool MCExpr::evaluateAsRelocatable(MCValue &Res,
596
const MCAsmLayout *Layout,
597
const MCFixup *Fixup) const {
598
MCAssembler *Assembler = Layout ? &Layout->getAssembler() : nullptr;
599
return evaluateAsRelocatableImpl(Res, Assembler, Layout, Fixup, nullptr,
603
bool MCExpr::evaluateAsValue(MCValue &Res, const MCAsmLayout &Layout) const {
604
MCAssembler *Assembler = &Layout.getAssembler();
605
return evaluateAsRelocatableImpl(Res, Assembler, &Layout, nullptr, nullptr,
609
static bool canExpand(const MCSymbol &Sym, const MCAssembler *Asm, bool InSet) {
610
const MCExpr *Expr = Sym.getVariableValue();
611
const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr);
613
if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF)
621
return !Asm->getWriter().isWeak(Sym);
624
bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
625
const MCAsmLayout *Layout,
626
const MCFixup *Fixup,
627
const SectionAddrMap *Addrs,
629
++stats::MCExprEvaluate;
633
return cast<MCTargetExpr>(this)->evaluateAsRelocatableImpl(Res, Layout,
637
Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
641
const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
642
const MCSymbol &Sym = SRE->getSymbol();
644
// Evaluate recursively if this is a variable.
645
if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None &&
646
canExpand(Sym, Asm, InSet)) {
647
bool IsMachO = SRE->hasSubsectionsViaSymbols();
648
if (Sym.getVariableValue()->evaluateAsRelocatableImpl(
649
Res, Asm, Layout, Fixup, Addrs, InSet || IsMachO)) {
653
const MCSymbolRefExpr *A = Res.getSymA();
654
const MCSymbolRefExpr *B = Res.getSymB();
655
// FIXME: This is small hack. Given
658
// the OS X assembler will completely drop the 4. We should probably
659
// include it in the relocation or produce an error if that is not
666
Res = MCValue::get(SRE, nullptr, 0);
671
const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
674
if (!AUE->getSubExpr()->evaluateAsRelocatableImpl(Value, Asm, Layout, Fixup,
678
switch (AUE->getOpcode()) {
679
case MCUnaryExpr::LNot:
680
if (!Value.isAbsolute())
682
Res = MCValue::get(!Value.getConstant());
684
case MCUnaryExpr::Minus:
685
/// -(a - b + const) ==> (b - a - const)
686
if (Value.getSymA() && !Value.getSymB())
688
Res = MCValue::get(Value.getSymB(), Value.getSymA(),
689
-Value.getConstant());
691
case MCUnaryExpr::Not:
692
if (!Value.isAbsolute())
694
Res = MCValue::get(~Value.getConstant());
696
case MCUnaryExpr::Plus:
705
const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
706
MCValue LHSValue, RHSValue;
708
if (!ABE->getLHS()->evaluateAsRelocatableImpl(LHSValue, Asm, Layout, Fixup,
710
!ABE->getRHS()->evaluateAsRelocatableImpl(RHSValue, Asm, Layout, Fixup,
714
// We only support a few operations on non-constant expressions, handle
716
if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
717
switch (ABE->getOpcode()) {
720
case MCBinaryExpr::Sub:
721
// Negate RHS and add.
722
return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
723
RHSValue.getSymB(), RHSValue.getSymA(),
724
-RHSValue.getConstant(), Res);
726
case MCBinaryExpr::Add:
727
return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
728
RHSValue.getSymA(), RHSValue.getSymB(),
729
RHSValue.getConstant(), Res);
733
// FIXME: We need target hooks for the evaluation. It may be limited in
734
// width, and gas defines the result of comparisons differently from
736
int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
738
switch (ABE->getOpcode()) {
739
case MCBinaryExpr::AShr: Result = LHS >> RHS; break;
740
case MCBinaryExpr::Add: Result = LHS + RHS; break;
741
case MCBinaryExpr::And: Result = LHS & RHS; break;
742
case MCBinaryExpr::Div: Result = LHS / RHS; break;
743
case MCBinaryExpr::EQ: Result = LHS == RHS; break;
744
case MCBinaryExpr::GT: Result = LHS > RHS; break;
745
case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
746
case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
747
case MCBinaryExpr::LOr: Result = LHS || RHS; break;
748
case MCBinaryExpr::LShr: Result = uint64_t(LHS) >> uint64_t(RHS); break;
749
case MCBinaryExpr::LT: Result = LHS < RHS; break;
750
case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
751
case MCBinaryExpr::Mod: Result = LHS % RHS; break;
752
case MCBinaryExpr::Mul: Result = LHS * RHS; break;
753
case MCBinaryExpr::NE: Result = LHS != RHS; break;
754
case MCBinaryExpr::Or: Result = LHS | RHS; break;
755
case MCBinaryExpr::Shl: Result = uint64_t(LHS) << uint64_t(RHS); break;
756
case MCBinaryExpr::Sub: Result = LHS - RHS; break;
757
case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
760
Res = MCValue::get(Result);
765
llvm_unreachable("Invalid assembly expression kind!");
768
MCSection *MCExpr::findAssociatedSection() const {
771
// We never look through target specific expressions.
772
return cast<MCTargetExpr>(this)->findAssociatedSection();
775
return MCSymbol::AbsolutePseudoSection;
778
const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
779
const MCSymbol &Sym = SRE->getSymbol();
782
return &Sym.getSection();
788
return cast<MCUnaryExpr>(this)->getSubExpr()->findAssociatedSection();
791
const MCBinaryExpr *BE = cast<MCBinaryExpr>(this);
792
MCSection *LHS_S = BE->getLHS()->findAssociatedSection();
793
MCSection *RHS_S = BE->getRHS()->findAssociatedSection();
795
// If either section is absolute, return the other.
796
if (LHS_S == MCSymbol::AbsolutePseudoSection)
798
if (RHS_S == MCSymbol::AbsolutePseudoSection)
801
// Not always correct, but probably the best we can do without more context.
802
if (BE->getOpcode() == MCBinaryExpr::Sub)
803
return MCSymbol::AbsolutePseudoSection;
805
// Otherwise, return the first non-null section.
806
return LHS_S ? LHS_S : RHS_S;
810
llvm_unreachable("Invalid assembly expression kind!");