1 //===- lib/MC/MCFragment.cpp - Assembler Fragment 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/MCFragment.h"
11 #include "llvm/ADT/StringExtras.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/MC/MCAsmBackend.h"
14 #include "llvm/MC/MCAsmInfo.h"
15 #include "llvm/MC/MCAsmLayout.h"
16 #include "llvm/MC/MCContext.h"
17 #include "llvm/MC/MCDwarf.h"
18 #include "llvm/MC/MCExpr.h"
19 #include "llvm/MC/MCFixupKindInfo.h"
20 #include "llvm/MC/MCSection.h"
21 #include "llvm/MC/MCSectionELF.h"
22 #include "llvm/MC/MCSymbol.h"
23 #include "llvm/MC/MCValue.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/LEB128.h"
26 #include "llvm/Support/TargetRegistry.h"
27 #include "llvm/Support/raw_ostream.h"
30 MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
31 : Assembler(Asm), LastValidFragment()
33 // Compute the section layout order. Virtual sections must go last.
34 for (MCSection &Sec : Asm)
35 if (!Sec.isVirtualSection())
36 SectionOrder.push_back(&Sec);
37 for (MCSection &Sec : Asm)
38 if (Sec.isVirtualSection())
39 SectionOrder.push_back(&Sec);
42 bool MCAsmLayout::isFragmentValid(const MCFragment *F) const {
43 const MCSection *Sec = F->getParent();
44 const MCFragment *LastValid = LastValidFragment.lookup(Sec);
47 assert(LastValid->getParent() == Sec);
48 return F->getLayoutOrder() <= LastValid->getLayoutOrder();
51 void MCAsmLayout::invalidateFragmentsFrom(MCFragment *F) {
52 // If this fragment wasn't already valid, we don't need to do anything.
53 if (!isFragmentValid(F))
56 // Otherwise, reset the last valid fragment to the previous fragment
57 // (if this is the first fragment, it will be NULL).
58 LastValidFragment[F->getParent()] = F->getPrevNode();
61 void MCAsmLayout::ensureValid(const MCFragment *F) const {
62 MCSection *Sec = F->getParent();
63 MCSection::iterator I;
64 if (MCFragment *Cur = LastValidFragment[Sec])
65 I = ++MCSection::iterator(Cur);
69 // Advance the layout position until the fragment is valid.
70 while (!isFragmentValid(F)) {
71 assert(I != Sec->end() && "Layout bookkeeping error");
72 const_cast<MCAsmLayout *>(this)->layoutFragment(&*I);
77 uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
79 assert(F->Offset != ~UINT64_C(0) && "Address not set!");
83 // Simple getSymbolOffset helper for the non-varibale case.
84 static bool getLabelOffset(const MCAsmLayout &Layout, const MCSymbol &S,
85 bool ReportError, uint64_t &Val) {
86 if (!S.getFragment()) {
88 report_fatal_error("unable to evaluate offset to undefined symbol '" +
92 Val = Layout.getFragmentOffset(S.getFragment()) + S.getOffset();
96 static bool getSymbolOffsetImpl(const MCAsmLayout &Layout, const MCSymbol &S,
97 bool ReportError, uint64_t &Val) {
99 return getLabelOffset(Layout, S, ReportError, Val);
101 // If SD is a variable, evaluate it.
103 if (!S.getVariableValue()->evaluateAsValue(Target, Layout))
104 report_fatal_error("unable to evaluate offset for variable '" +
107 uint64_t Offset = Target.getConstant();
109 const MCSymbolRefExpr *A = Target.getSymA();
112 if (!getLabelOffset(Layout, A->getSymbol(), ReportError, ValA))
117 const MCSymbolRefExpr *B = Target.getSymB();
120 if (!getLabelOffset(Layout, B->getSymbol(), ReportError, ValB))
129 bool MCAsmLayout::getSymbolOffset(const MCSymbol &S, uint64_t &Val) const {
130 return getSymbolOffsetImpl(*this, S, false, Val);
133 uint64_t MCAsmLayout::getSymbolOffset(const MCSymbol &S) const {
135 getSymbolOffsetImpl(*this, S, true, Val);
139 const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
140 if (!Symbol.isVariable())
143 const MCExpr *Expr = Symbol.getVariableValue();
145 if (!Expr->evaluateAsValue(Value, *this)) {
146 Assembler.getContext().reportError(
147 SMLoc(), "expression could not be evaluated");
151 const MCSymbolRefExpr *RefB = Value.getSymB();
153 Assembler.getContext().reportError(
154 SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
155 "' could not be evaluated in a subtraction expression");
159 const MCSymbolRefExpr *A = Value.getSymA();
163 const MCSymbol &ASym = A->getSymbol();
164 const MCAssembler &Asm = getAssembler();
165 if (ASym.isCommon()) {
166 // FIXME: we should probably add a SMLoc to MCExpr.
167 Asm.getContext().reportError(SMLoc(),
168 "Common symbol '" + ASym.getName() +
169 "' cannot be used in assignment expr");
176 uint64_t MCAsmLayout::getSectionAddressSize(const MCSection *Sec) const {
177 // The size is the last fragment's end offset.
178 const MCFragment &F = Sec->getFragmentList().back();
179 return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
182 uint64_t MCAsmLayout::getSectionFileSize(const MCSection *Sec) const {
183 // Virtual sections have no file size.
184 if (Sec->isVirtualSection())
187 // Otherwise, the file size is the same as the address space size.
188 return getSectionAddressSize(Sec);
191 uint64_t llvm::computeBundlePadding(const MCAssembler &Assembler,
193 uint64_t FOffset, uint64_t FSize) {
194 uint64_t BundleSize = Assembler.getBundleAlignSize();
195 assert(BundleSize > 0 &&
196 "computeBundlePadding should only be called if bundling is enabled");
197 uint64_t BundleMask = BundleSize - 1;
198 uint64_t OffsetInBundle = FOffset & BundleMask;
199 uint64_t EndOfFragment = OffsetInBundle + FSize;
201 // There are two kinds of bundling restrictions:
203 // 1) For alignToBundleEnd(), add padding to ensure that the fragment will
204 // *end* on a bundle boundary.
205 // 2) Otherwise, check if the fragment would cross a bundle boundary. If it
206 // would, add padding until the end of the bundle so that the fragment
207 // will start in a new one.
208 if (F->alignToBundleEnd()) {
209 // Three possibilities here:
211 // A) The fragment just happens to end at a bundle boundary, so we're good.
212 // B) The fragment ends before the current bundle boundary: pad it just
213 // enough to reach the boundary.
214 // C) The fragment ends after the current bundle boundary: pad it until it
215 // reaches the end of the next bundle boundary.
217 // Note: this code could be made shorter with some modulo trickery, but it's
218 // intentionally kept in its more explicit form for simplicity.
219 if (EndOfFragment == BundleSize)
221 else if (EndOfFragment < BundleSize)
222 return BundleSize - EndOfFragment;
223 else { // EndOfFragment > BundleSize
224 return 2 * BundleSize - EndOfFragment;
226 } else if (OffsetInBundle > 0 && EndOfFragment > BundleSize)
227 return BundleSize - OffsetInBundle;
234 void ilist_node_traits<MCFragment>::deleteNode(MCFragment *V) {
238 MCFragment::MCFragment() : Kind(FragmentType(~0)), HasInstructions(false),
239 AlignToBundleEnd(false), BundlePadding(0) {
242 MCFragment::~MCFragment() { }
244 MCFragment::MCFragment(FragmentType Kind, bool HasInstructions,
245 uint8_t BundlePadding, MCSection *Parent)
246 : Kind(Kind), HasInstructions(HasInstructions), AlignToBundleEnd(false),
247 BundlePadding(BundlePadding), Parent(Parent), Atom(nullptr),
248 Offset(~UINT64_C(0)) {
249 if (Parent && !isDummy())
250 Parent->getFragmentList().push_back(this);
253 void MCFragment::destroy() {
254 // First check if we are the sentinal.
255 if (Kind == FragmentType(~0)) {
262 delete cast<MCAlignFragment>(this);
265 delete cast<MCDataFragment>(this);
267 case FT_CompactEncodedInst:
268 delete cast<MCCompactEncodedInstFragment>(this);
271 delete cast<MCFillFragment>(this);
274 delete cast<MCRelaxableFragment>(this);
277 delete cast<MCOrgFragment>(this);
280 delete cast<MCDwarfLineAddrFragment>(this);
283 delete cast<MCDwarfCallFrameFragment>(this);
286 delete cast<MCLEBFragment>(this);
289 delete cast<MCSafeSEHFragment>(this);
291 case FT_CVInlineLines:
292 delete cast<MCCVInlineLineTableFragment>(this);
295 delete cast<MCCVDefRangeFragment>(this);
298 delete cast<MCDummyFragment>(this);
309 raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
310 OS << "<MCFixup" << " Offset:" << AF.getOffset()
311 << " Value:" << *AF.getValue()
312 << " Kind:" << AF.getKind() << ">";
318 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
319 LLVM_DUMP_METHOD void MCFragment::dump() {
320 raw_ostream &OS = llvm::errs();
324 case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
325 case MCFragment::FT_Data: OS << "MCDataFragment"; break;
326 case MCFragment::FT_CompactEncodedInst:
327 OS << "MCCompactEncodedInstFragment"; break;
328 case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
329 case MCFragment::FT_Relaxable: OS << "MCRelaxableFragment"; break;
330 case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
331 case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
332 case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
333 case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
334 case MCFragment::FT_SafeSEH: OS << "MCSafeSEHFragment"; break;
335 case MCFragment::FT_CVInlineLines: OS << "MCCVInlineLineTableFragment"; break;
336 case MCFragment::FT_CVDefRange: OS << "MCCVDefRangeTableFragment"; break;
337 case MCFragment::FT_Dummy: OS << "MCDummyFragment"; break;
340 OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
341 << " Offset:" << Offset
342 << " HasInstructions:" << hasInstructions()
343 << " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
346 case MCFragment::FT_Align: {
347 const MCAlignFragment *AF = cast<MCAlignFragment>(this);
348 if (AF->hasEmitNops())
349 OS << " (emit nops)";
351 OS << " Alignment:" << AF->getAlignment()
352 << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
353 << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
356 case MCFragment::FT_Data: {
357 const MCDataFragment *DF = cast<MCDataFragment>(this);
360 const SmallVectorImpl<char> &Contents = DF->getContents();
361 for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
363 OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
365 OS << "] (" << Contents.size() << " bytes)";
367 if (DF->fixup_begin() != DF->fixup_end()) {
370 for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
371 ie = DF->fixup_end(); it != ie; ++it) {
372 if (it != DF->fixup_begin()) OS << ",\n ";
379 case MCFragment::FT_CompactEncodedInst: {
380 const MCCompactEncodedInstFragment *CEIF =
381 cast<MCCompactEncodedInstFragment>(this);
384 const SmallVectorImpl<char> &Contents = CEIF->getContents();
385 for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
387 OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
389 OS << "] (" << Contents.size() << " bytes)";
392 case MCFragment::FT_Fill: {
393 const MCFillFragment *FF = cast<MCFillFragment>(this);
394 OS << " Value:" << FF->getValue() << " Size:" << FF->getSize();
397 case MCFragment::FT_Relaxable: {
398 const MCRelaxableFragment *F = cast<MCRelaxableFragment>(this);
401 F->getInst().dump_pretty(OS);
404 case MCFragment::FT_Org: {
405 const MCOrgFragment *OF = cast<MCOrgFragment>(this);
407 OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
410 case MCFragment::FT_Dwarf: {
411 const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
413 OS << " AddrDelta:" << OF->getAddrDelta()
414 << " LineDelta:" << OF->getLineDelta();
417 case MCFragment::FT_DwarfFrame: {
418 const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
420 OS << " AddrDelta:" << CF->getAddrDelta();
423 case MCFragment::FT_LEB: {
424 const MCLEBFragment *LF = cast<MCLEBFragment>(this);
426 OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
429 case MCFragment::FT_SafeSEH: {
430 const MCSafeSEHFragment *F = cast<MCSafeSEHFragment>(this);
432 OS << " Sym:" << F->getSymbol();
435 case MCFragment::FT_CVInlineLines: {
436 const auto *F = cast<MCCVInlineLineTableFragment>(this);
438 OS << " Sym:" << *F->getFnStartSym();
441 case MCFragment::FT_CVDefRange: {
442 const auto *F = cast<MCCVDefRangeFragment>(this);
444 for (std::pair<const MCSymbol *, const MCSymbol *> RangeStartEnd :
446 OS << " RangeStart:" << RangeStartEnd.first;
447 OS << " RangeEnd:" << RangeStartEnd.second;
451 case MCFragment::FT_Dummy:
457 LLVM_DUMP_METHOD void MCAssembler::dump() {
458 raw_ostream &OS = llvm::errs();
460 OS << "<MCAssembler\n";
461 OS << " Sections:[\n ";
462 for (iterator it = begin(), ie = end(); it != ie; ++it) {
463 if (it != begin()) OS << ",\n ";
469 for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
470 if (it != symbol_begin()) OS << ",\n ";
473 OS << ", Index:" << it->getIndex() << ", ";