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-rw-r--r--contrib/llvm/lib/MC/MCAssembler.cpp975
1 files changed, 975 insertions, 0 deletions
diff --git a/contrib/llvm/lib/MC/MCAssembler.cpp b/contrib/llvm/lib/MC/MCAssembler.cpp
new file mode 100644
index 0000000..66ba9b8
--- /dev/null
+++ b/contrib/llvm/lib/MC/MCAssembler.cpp
@@ -0,0 +1,975 @@
+//===- lib/MC/MCAssembler.cpp - Assembler Backend Implementation ----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "assembler"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCAsmLayout.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/MC/MCDwarf.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/TargetRegistry.h"
+
+using namespace llvm;
+
+namespace {
+namespace stats {
+STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
+STATISTIC(evaluateFixup, "Number of evaluated fixups");
+STATISTIC(FragmentLayouts, "Number of fragment layouts");
+STATISTIC(ObjectBytes, "Number of emitted object file bytes");
+STATISTIC(RelaxationSteps, "Number of assembler layout and relaxation steps");
+STATISTIC(RelaxedInstructions, "Number of relaxed instructions");
+}
+}
+
+// FIXME FIXME FIXME: There are number of places in this file where we convert
+// what is a 64-bit assembler value used for computation into a value in the
+// object file, which may truncate it. We should detect that truncation where
+// invalid and report errors back.
+
+/* *** */
+
+MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
+ : Assembler(Asm), LastValidFragment()
+ {
+ // Compute the section layout order. Virtual sections must go last.
+ for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
+ if (!it->getSection().isVirtualSection())
+ SectionOrder.push_back(&*it);
+ for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
+ if (it->getSection().isVirtualSection())
+ SectionOrder.push_back(&*it);
+}
+
+bool MCAsmLayout::isFragmentUpToDate(const MCFragment *F) const {
+ const MCSectionData &SD = *F->getParent();
+ const MCFragment *LastValid = LastValidFragment.lookup(&SD);
+ if (!LastValid)
+ return false;
+ assert(LastValid->getParent() == F->getParent());
+ return F->getLayoutOrder() <= LastValid->getLayoutOrder();
+}
+
+void MCAsmLayout::Invalidate(MCFragment *F) {
+ // If this fragment wasn't already up-to-date, we don't need to do anything.
+ if (!isFragmentUpToDate(F))
+ return;
+
+ // Otherwise, reset the last valid fragment to this fragment.
+ const MCSectionData &SD = *F->getParent();
+ LastValidFragment[&SD] = F;
+}
+
+void MCAsmLayout::EnsureValid(const MCFragment *F) const {
+ MCSectionData &SD = *F->getParent();
+
+ MCFragment *Cur = LastValidFragment[&SD];
+ if (!Cur)
+ Cur = &*SD.begin();
+ else
+ Cur = Cur->getNextNode();
+
+ // Advance the layout position until the fragment is up-to-date.
+ while (!isFragmentUpToDate(F)) {
+ const_cast<MCAsmLayout*>(this)->LayoutFragment(Cur);
+ Cur = Cur->getNextNode();
+ }
+}
+
+uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
+ EnsureValid(F);
+ assert(F->Offset != ~UINT64_C(0) && "Address not set!");
+ return F->Offset;
+}
+
+uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
+ const MCSymbol &S = SD->getSymbol();
+
+ // If this is a variable, then recursively evaluate now.
+ if (S.isVariable()) {
+ MCValue Target;
+ if (!S.getVariableValue()->EvaluateAsRelocatable(Target, *this))
+ report_fatal_error("unable to evaluate offset for variable '" +
+ S.getName() + "'");
+
+ // Verify that any used symbols are defined.
+ if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined())
+ report_fatal_error("unable to evaluate offset to undefined symbol '" +
+ Target.getSymA()->getSymbol().getName() + "'");
+ if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined())
+ report_fatal_error("unable to evaluate offset to undefined symbol '" +
+ Target.getSymB()->getSymbol().getName() + "'");
+
+ uint64_t Offset = Target.getConstant();
+ if (Target.getSymA())
+ Offset += getSymbolOffset(&Assembler.getSymbolData(
+ Target.getSymA()->getSymbol()));
+ if (Target.getSymB())
+ Offset -= getSymbolOffset(&Assembler.getSymbolData(
+ Target.getSymB()->getSymbol()));
+ return Offset;
+ }
+
+ assert(SD->getFragment() && "Invalid getOffset() on undefined symbol!");
+ return getFragmentOffset(SD->getFragment()) + SD->getOffset();
+}
+
+uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
+ // The size is the last fragment's end offset.
+ const MCFragment &F = SD->getFragmentList().back();
+ return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
+}
+
+uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
+ // Virtual sections have no file size.
+ if (SD->getSection().isVirtualSection())
+ return 0;
+
+ // Otherwise, the file size is the same as the address space size.
+ return getSectionAddressSize(SD);
+}
+
+/* *** */
+
+MCFragment::MCFragment() : Kind(FragmentType(~0)) {
+}
+
+MCFragment::~MCFragment() {
+}
+
+MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
+ : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
+{
+ if (Parent)
+ Parent->getFragmentList().push_back(this);
+}
+
+/* *** */
+
+MCSectionData::MCSectionData() : Section(0) {}
+
+MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
+ : Section(&_Section),
+ Ordinal(~UINT32_C(0)),
+ Alignment(1),
+ HasInstructions(false)
+{
+ if (A)
+ A->getSectionList().push_back(this);
+}
+
+/* *** */
+
+MCSymbolData::MCSymbolData() : Symbol(0) {}
+
+MCSymbolData::MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment,
+ uint64_t _Offset, MCAssembler *A)
+ : Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
+ IsExternal(false), IsPrivateExtern(false),
+ CommonSize(0), SymbolSize(0), CommonAlign(0),
+ Flags(0), Index(0)
+{
+ if (A)
+ A->getSymbolList().push_back(this);
+}
+
+/* *** */
+
+MCAssembler::MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
+ MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
+ raw_ostream &OS_)
+ : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
+ OS(OS_), RelaxAll(false), NoExecStack(false), SubsectionsViaSymbols(false)
+{
+}
+
+MCAssembler::~MCAssembler() {
+}
+
+bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
+ // Non-temporary labels should always be visible to the linker.
+ if (!Symbol.isTemporary())
+ return true;
+
+ // Absolute temporary labels are never visible.
+ if (!Symbol.isInSection())
+ return false;
+
+ // Otherwise, check if the section requires symbols even for temporary labels.
+ return getBackend().doesSectionRequireSymbols(Symbol.getSection());
+}
+
+const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
+ // Linker visible symbols define atoms.
+ if (isSymbolLinkerVisible(SD->getSymbol()))
+ return SD;
+
+ // Absolute and undefined symbols have no defining atom.
+ if (!SD->getFragment())
+ return 0;
+
+ // Non-linker visible symbols in sections which can't be atomized have no
+ // defining atom.
+ if (!getBackend().isSectionAtomizable(
+ SD->getFragment()->getParent()->getSection()))
+ return 0;
+
+ // Otherwise, return the atom for the containing fragment.
+ return SD->getFragment()->getAtom();
+}
+
+bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
+ const MCFixup &Fixup, const MCFragment *DF,
+ MCValue &Target, uint64_t &Value) const {
+ ++stats::evaluateFixup;
+
+ if (!Fixup.getValue()->EvaluateAsRelocatable(Target, Layout))
+ getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
+
+ bool IsPCRel = Backend.getFixupKindInfo(
+ Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
+
+ bool IsResolved;
+ if (IsPCRel) {
+ if (Target.getSymB()) {
+ IsResolved = false;
+ } else if (!Target.getSymA()) {
+ IsResolved = false;
+ } else {
+ const MCSymbolRefExpr *A = Target.getSymA();
+ const MCSymbol &SA = A->getSymbol();
+ if (A->getKind() != MCSymbolRefExpr::VK_None ||
+ SA.AliasedSymbol().isUndefined()) {
+ IsResolved = false;
+ } else {
+ const MCSymbolData &DataA = getSymbolData(SA);
+ IsResolved =
+ getWriter().IsSymbolRefDifferenceFullyResolvedImpl(*this, DataA,
+ *DF, false, true);
+ }
+ }
+ } else {
+ IsResolved = Target.isAbsolute();
+ }
+
+ Value = Target.getConstant();
+
+ if (const MCSymbolRefExpr *A = Target.getSymA()) {
+ const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value += Layout.getSymbolOffset(&getSymbolData(Sym));
+ }
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
+ }
+
+
+ bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
+ MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
+ assert((ShouldAlignPC ? IsPCRel : true) &&
+ "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
+
+ if (IsPCRel) {
+ uint32_t Offset = Layout.getFragmentOffset(DF) + Fixup.getOffset();
+
+ // A number of ARM fixups in Thumb mode require that the effective PC
+ // address be determined as the 32-bit aligned version of the actual offset.
+ if (ShouldAlignPC) Offset &= ~0x3;
+ Value -= Offset;
+ }
+
+ // Let the backend adjust the fixup value if necessary, including whether
+ // we need a relocation.
+ Backend.processFixupValue(*this, Layout, Fixup, DF, Target, Value,
+ IsResolved);
+
+ return IsResolved;
+}
+
+uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
+ const MCFragment &F) const {
+ switch (F.getKind()) {
+ case MCFragment::FT_Data:
+ return cast<MCDataFragment>(F).getContents().size();
+ case MCFragment::FT_Fill:
+ return cast<MCFillFragment>(F).getSize();
+ case MCFragment::FT_Inst:
+ return cast<MCInstFragment>(F).getInstSize();
+
+ case MCFragment::FT_LEB:
+ return cast<MCLEBFragment>(F).getContents().size();
+
+ case MCFragment::FT_Align: {
+ const MCAlignFragment &AF = cast<MCAlignFragment>(F);
+ unsigned Offset = Layout.getFragmentOffset(&AF);
+ unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
+ if (Size > AF.getMaxBytesToEmit())
+ return 0;
+ return Size;
+ }
+
+ case MCFragment::FT_Org: {
+ MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ int64_t TargetLocation;
+ if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
+ report_fatal_error("expected assembly-time absolute expression");
+
+ // FIXME: We need a way to communicate this error.
+ uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
+ int64_t Size = TargetLocation - FragmentOffset;
+ if (Size < 0 || Size >= 0x40000000)
+ report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
+ "' (at offset '" + Twine(FragmentOffset) + "')");
+ return Size;
+ }
+
+ case MCFragment::FT_Dwarf:
+ return cast<MCDwarfLineAddrFragment>(F).getContents().size();
+ case MCFragment::FT_DwarfFrame:
+ return cast<MCDwarfCallFrameFragment>(F).getContents().size();
+ }
+
+ llvm_unreachable("invalid fragment kind");
+}
+
+void MCAsmLayout::LayoutFragment(MCFragment *F) {
+ MCFragment *Prev = F->getPrevNode();
+
+ // We should never try to recompute something which is up-to-date.
+ assert(!isFragmentUpToDate(F) && "Attempt to recompute up-to-date fragment!");
+ // We should never try to compute the fragment layout if it's predecessor
+ // isn't up-to-date.
+ assert((!Prev || isFragmentUpToDate(Prev)) &&
+ "Attempt to compute fragment before it's predecessor!");
+
+ ++stats::FragmentLayouts;
+
+ // Compute fragment offset and size.
+ uint64_t Offset = 0;
+ if (Prev)
+ Offset += Prev->Offset + getAssembler().computeFragmentSize(*this, *Prev);
+
+ F->Offset = Offset;
+ LastValidFragment[F->getParent()] = F;
+}
+
+/// WriteFragmentData - Write the \arg F data to the output file.
+static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment &F) {
+ MCObjectWriter *OW = &Asm.getWriter();
+ uint64_t Start = OW->getStream().tell();
+ (void) Start;
+
+ ++stats::EmittedFragments;
+
+ // FIXME: Embed in fragments instead?
+ uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
+ switch (F.getKind()) {
+ case MCFragment::FT_Align: {
+ MCAlignFragment &AF = cast<MCAlignFragment>(F);
+ uint64_t Count = FragmentSize / AF.getValueSize();
+
+ assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
+
+ // FIXME: This error shouldn't actually occur (the front end should emit
+ // multiple .align directives to enforce the semantics it wants), but is
+ // severe enough that we want to report it. How to handle this?
+ if (Count * AF.getValueSize() != FragmentSize)
+ report_fatal_error("undefined .align directive, value size '" +
+ Twine(AF.getValueSize()) +
+ "' is not a divisor of padding size '" +
+ Twine(FragmentSize) + "'");
+
+ // See if we are aligning with nops, and if so do that first to try to fill
+ // the Count bytes. Then if that did not fill any bytes or there are any
+ // bytes left to fill use the the Value and ValueSize to fill the rest.
+ // If we are aligning with nops, ask that target to emit the right data.
+ if (AF.hasEmitNops()) {
+ if (!Asm.getBackend().writeNopData(Count, OW))
+ report_fatal_error("unable to write nop sequence of " +
+ Twine(Count) + " bytes");
+ break;
+ }
+
+ // Otherwise, write out in multiples of the value size.
+ for (uint64_t i = 0; i != Count; ++i) {
+ switch (AF.getValueSize()) {
+ default: llvm_unreachable("Invalid size!");
+ case 1: OW->Write8 (uint8_t (AF.getValue())); break;
+ case 2: OW->Write16(uint16_t(AF.getValue())); break;
+ case 4: OW->Write32(uint32_t(AF.getValue())); break;
+ case 8: OW->Write64(uint64_t(AF.getValue())); break;
+ }
+ }
+ break;
+ }
+
+ case MCFragment::FT_Data: {
+ MCDataFragment &DF = cast<MCDataFragment>(F);
+ assert(FragmentSize == DF.getContents().size() && "Invalid size!");
+ OW->WriteBytes(DF.getContents().str());
+ break;
+ }
+
+ case MCFragment::FT_Fill: {
+ MCFillFragment &FF = cast<MCFillFragment>(F);
+
+ assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");
+
+ for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
+ switch (FF.getValueSize()) {
+ default: llvm_unreachable("Invalid size!");
+ case 1: OW->Write8 (uint8_t (FF.getValue())); break;
+ case 2: OW->Write16(uint16_t(FF.getValue())); break;
+ case 4: OW->Write32(uint32_t(FF.getValue())); break;
+ case 8: OW->Write64(uint64_t(FF.getValue())); break;
+ }
+ }
+ break;
+ }
+
+ case MCFragment::FT_Inst: {
+ MCInstFragment &IF = cast<MCInstFragment>(F);
+ OW->WriteBytes(StringRef(IF.getCode().begin(), IF.getCode().size()));
+ break;
+ }
+
+ case MCFragment::FT_LEB: {
+ MCLEBFragment &LF = cast<MCLEBFragment>(F);
+ OW->WriteBytes(LF.getContents().str());
+ break;
+ }
+
+ case MCFragment::FT_Org: {
+ MCOrgFragment &OF = cast<MCOrgFragment>(F);
+
+ for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
+ OW->Write8(uint8_t(OF.getValue()));
+
+ break;
+ }
+
+ case MCFragment::FT_Dwarf: {
+ const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
+ OW->WriteBytes(OF.getContents().str());
+ break;
+ }
+ case MCFragment::FT_DwarfFrame: {
+ const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
+ OW->WriteBytes(CF.getContents().str());
+ break;
+ }
+ }
+
+ assert(OW->getStream().tell() - Start == FragmentSize);
+}
+
+void MCAssembler::writeSectionData(const MCSectionData *SD,
+ const MCAsmLayout &Layout) const {
+ // Ignore virtual sections.
+ if (SD->getSection().isVirtualSection()) {
+ assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
+
+ // Check that contents are only things legal inside a virtual section.
+ for (MCSectionData::const_iterator it = SD->begin(),
+ ie = SD->end(); it != ie; ++it) {
+ switch (it->getKind()) {
+ default: llvm_unreachable("Invalid fragment in virtual section!");
+ case MCFragment::FT_Data: {
+ // Check that we aren't trying to write a non-zero contents (or fixups)
+ // into a virtual section. This is to support clients which use standard
+ // directives to fill the contents of virtual sections.
+ MCDataFragment &DF = cast<MCDataFragment>(*it);
+ assert(DF.fixup_begin() == DF.fixup_end() &&
+ "Cannot have fixups in virtual section!");
+ for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
+ assert(DF.getContents()[i] == 0 &&
+ "Invalid data value for virtual section!");
+ break;
+ }
+ case MCFragment::FT_Align:
+ // Check that we aren't trying to write a non-zero value into a virtual
+ // section.
+ assert((!cast<MCAlignFragment>(it)->getValueSize() ||
+ !cast<MCAlignFragment>(it)->getValue()) &&
+ "Invalid align in virtual section!");
+ break;
+ case MCFragment::FT_Fill:
+ assert(!cast<MCFillFragment>(it)->getValueSize() &&
+ "Invalid fill in virtual section!");
+ break;
+ }
+ }
+
+ return;
+ }
+
+ uint64_t Start = getWriter().getStream().tell();
+ (void) Start;
+
+ for (MCSectionData::const_iterator it = SD->begin(),
+ ie = SD->end(); it != ie; ++it)
+ WriteFragmentData(*this, Layout, *it);
+
+ assert(getWriter().getStream().tell() - Start ==
+ Layout.getSectionAddressSize(SD));
+}
+
+
+uint64_t MCAssembler::handleFixup(const MCAsmLayout &Layout,
+ MCFragment &F,
+ const MCFixup &Fixup) {
+ // Evaluate the fixup.
+ MCValue Target;
+ uint64_t FixedValue;
+ if (!evaluateFixup(Layout, Fixup, &F, Target, FixedValue)) {
+ // The fixup was unresolved, we need a relocation. Inform the object
+ // writer of the relocation, and give it an opportunity to adjust the
+ // fixup value if need be.
+ getWriter().RecordRelocation(*this, Layout, &F, Fixup, Target, FixedValue);
+ }
+ return FixedValue;
+ }
+
+void MCAssembler::Finish() {
+ DEBUG_WITH_TYPE("mc-dump", {
+ llvm::errs() << "assembler backend - pre-layout\n--\n";
+ dump(); });
+
+ // Create the layout object.
+ MCAsmLayout Layout(*this);
+
+ // Create dummy fragments and assign section ordinals.
+ unsigned SectionIndex = 0;
+ for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
+ // Create dummy fragments to eliminate any empty sections, this simplifies
+ // layout.
+ if (it->getFragmentList().empty())
+ new MCDataFragment(it);
+
+ it->setOrdinal(SectionIndex++);
+ }
+
+ // Assign layout order indices to sections and fragments.
+ for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
+ MCSectionData *SD = Layout.getSectionOrder()[i];
+ SD->setLayoutOrder(i);
+
+ unsigned FragmentIndex = 0;
+ for (MCSectionData::iterator it2 = SD->begin(),
+ ie2 = SD->end(); it2 != ie2; ++it2)
+ it2->setLayoutOrder(FragmentIndex++);
+ }
+
+ // Layout until everything fits.
+ while (layoutOnce(Layout))
+ continue;
+
+ DEBUG_WITH_TYPE("mc-dump", {
+ llvm::errs() << "assembler backend - post-relaxation\n--\n";
+ dump(); });
+
+ // Finalize the layout, including fragment lowering.
+ finishLayout(Layout);
+
+ DEBUG_WITH_TYPE("mc-dump", {
+ llvm::errs() << "assembler backend - final-layout\n--\n";
+ dump(); });
+
+ uint64_t StartOffset = OS.tell();
+
+ // Allow the object writer a chance to perform post-layout binding (for
+ // example, to set the index fields in the symbol data).
+ getWriter().ExecutePostLayoutBinding(*this, Layout);
+
+ // Evaluate and apply the fixups, generating relocation entries as necessary.
+ for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
+ for (MCSectionData::iterator it2 = it->begin(),
+ ie2 = it->end(); it2 != ie2; ++it2) {
+ MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
+ if (DF) {
+ for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
+ ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
+ MCFixup &Fixup = *it3;
+ uint64_t FixedValue = handleFixup(Layout, *DF, Fixup);
+ getBackend().applyFixup(Fixup, DF->getContents().data(),
+ DF->getContents().size(), FixedValue);
+ }
+ }
+ MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
+ if (IF) {
+ for (MCInstFragment::fixup_iterator it3 = IF->fixup_begin(),
+ ie3 = IF->fixup_end(); it3 != ie3; ++it3) {
+ MCFixup &Fixup = *it3;
+ uint64_t FixedValue = handleFixup(Layout, *IF, Fixup);
+ getBackend().applyFixup(Fixup, IF->getCode().data(),
+ IF->getCode().size(), FixedValue);
+ }
+ }
+ }
+ }
+
+ // Write the object file.
+ getWriter().WriteObject(*this, Layout);
+
+ stats::ObjectBytes += OS.tell() - StartOffset;
+}
+
+bool MCAssembler::fixupNeedsRelaxation(const MCFixup &Fixup,
+ const MCInstFragment *DF,
+ const MCAsmLayout &Layout) const {
+ if (getRelaxAll())
+ return true;
+
+ // If we cannot resolve the fixup value, it requires relaxation.
+ MCValue Target;
+ uint64_t Value;
+ if (!evaluateFixup(Layout, Fixup, DF, Target, Value))
+ return true;
+
+ return getBackend().fixupNeedsRelaxation(Fixup, Value, DF, Layout);
+}
+
+bool MCAssembler::fragmentNeedsRelaxation(const MCInstFragment *IF,
+ const MCAsmLayout &Layout) const {
+ // If this inst doesn't ever need relaxation, ignore it. This occurs when we
+ // are intentionally pushing out inst fragments, or because we relaxed a
+ // previous instruction to one that doesn't need relaxation.
+ if (!getBackend().mayNeedRelaxation(IF->getInst()))
+ return false;
+
+ for (MCInstFragment::const_fixup_iterator it = IF->fixup_begin(),
+ ie = IF->fixup_end(); it != ie; ++it)
+ if (fixupNeedsRelaxation(*it, IF, Layout))
+ return true;
+
+ return false;
+}
+
+bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
+ MCInstFragment &IF) {
+ if (!fragmentNeedsRelaxation(&IF, Layout))
+ return false;
+
+ ++stats::RelaxedInstructions;
+
+ // FIXME-PERF: We could immediately lower out instructions if we can tell
+ // they are fully resolved, to avoid retesting on later passes.
+
+ // Relax the fragment.
+
+ MCInst Relaxed;
+ getBackend().relaxInstruction(IF.getInst(), Relaxed);
+
+ // Encode the new instruction.
+ //
+ // FIXME-PERF: If it matters, we could let the target do this. It can
+ // probably do so more efficiently in many cases.
+ SmallVector<MCFixup, 4> Fixups;
+ SmallString<256> Code;
+ raw_svector_ostream VecOS(Code);
+ getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups);
+ VecOS.flush();
+
+ // Update the instruction fragment.
+ IF.setInst(Relaxed);
+ IF.getCode() = Code;
+ IF.getFixups().clear();
+ // FIXME: Eliminate copy.
+ for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
+ IF.getFixups().push_back(Fixups[i]);
+
+ return true;
+}
+
+bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
+ int64_t Value = 0;
+ uint64_t OldSize = LF.getContents().size();
+ bool IsAbs = LF.getValue().EvaluateAsAbsolute(Value, Layout);
+ (void)IsAbs;
+ assert(IsAbs);
+ SmallString<8> &Data = LF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ if (LF.isSigned())
+ MCObjectWriter::EncodeSLEB128(Value, OSE);
+ else
+ MCObjectWriter::EncodeULEB128(Value, OSE);
+ OSE.flush();
+ return OldSize != LF.getContents().size();
+}
+
+bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
+ MCDwarfLineAddrFragment &DF) {
+ int64_t AddrDelta = 0;
+ uint64_t OldSize = DF.getContents().size();
+ bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
+ (void)IsAbs;
+ assert(IsAbs);
+ int64_t LineDelta;
+ LineDelta = DF.getLineDelta();
+ SmallString<8> &Data = DF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
+
+bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
+ MCDwarfCallFrameFragment &DF) {
+ int64_t AddrDelta = 0;
+ uint64_t OldSize = DF.getContents().size();
+ bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
+ (void)IsAbs;
+ assert(IsAbs);
+ SmallString<8> &Data = DF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
+
+bool MCAssembler::layoutSectionOnce(MCAsmLayout &Layout,
+ MCSectionData &SD) {
+ MCFragment *FirstInvalidFragment = NULL;
+ // Scan for fragments that need relaxation.
+ for (MCSectionData::iterator it2 = SD.begin(),
+ ie2 = SD.end(); it2 != ie2; ++it2) {
+ // Check if this is an fragment that needs relaxation.
+ bool relaxedFrag = false;
+ switch(it2->getKind()) {
+ default:
+ break;
+ case MCFragment::FT_Inst:
+ relaxedFrag = relaxInstruction(Layout, *cast<MCInstFragment>(it2));
+ break;
+ case MCFragment::FT_Dwarf:
+ relaxedFrag = relaxDwarfLineAddr(Layout,
+ *cast<MCDwarfLineAddrFragment>(it2));
+ break;
+ case MCFragment::FT_DwarfFrame:
+ relaxedFrag =
+ relaxDwarfCallFrameFragment(Layout,
+ *cast<MCDwarfCallFrameFragment>(it2));
+ break;
+ case MCFragment::FT_LEB:
+ relaxedFrag = relaxLEB(Layout, *cast<MCLEBFragment>(it2));
+ break;
+ }
+ // Update the layout, and remember that we relaxed.
+ if (relaxedFrag && !FirstInvalidFragment)
+ FirstInvalidFragment = it2;
+ }
+ if (FirstInvalidFragment) {
+ Layout.Invalidate(FirstInvalidFragment);
+ return true;
+ }
+ return false;
+}
+
+bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
+ ++stats::RelaxationSteps;
+
+ bool WasRelaxed = false;
+ for (iterator it = begin(), ie = end(); it != ie; ++it) {
+ MCSectionData &SD = *it;
+ while(layoutSectionOnce(Layout, SD))
+ WasRelaxed = true;
+ }
+
+ return WasRelaxed;
+}
+
+void MCAssembler::finishLayout(MCAsmLayout &Layout) {
+ // The layout is done. Mark every fragment as valid.
+ for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
+ Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
+ }
+}
+
+// Debugging methods
+
+namespace llvm {
+
+raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
+ OS << "<MCFixup" << " Offset:" << AF.getOffset()
+ << " Value:" << *AF.getValue()
+ << " Kind:" << AF.getKind() << ">";
+ return OS;
+}
+
+}
+
+void MCFragment::dump() {
+ raw_ostream &OS = llvm::errs();
+
+ OS << "<";
+ switch (getKind()) {
+ case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
+ case MCFragment::FT_Data: OS << "MCDataFragment"; break;
+ case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
+ case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
+ case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
+ case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
+ case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
+ case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
+ }
+
+ OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
+ << " Offset:" << Offset << ">";
+
+ switch (getKind()) {
+ case MCFragment::FT_Align: {
+ const MCAlignFragment *AF = cast<MCAlignFragment>(this);
+ if (AF->hasEmitNops())
+ OS << " (emit nops)";
+ OS << "\n ";
+ OS << " Alignment:" << AF->getAlignment()
+ << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
+ << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
+ break;
+ }
+ case MCFragment::FT_Data: {
+ const MCDataFragment *DF = cast<MCDataFragment>(this);
+ OS << "\n ";
+ OS << " Contents:[";
+ const SmallVectorImpl<char> &Contents = DF->getContents();
+ for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
+ if (i) OS << ",";
+ OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
+ }
+ OS << "] (" << Contents.size() << " bytes)";
+
+ if (!DF->getFixups().empty()) {
+ OS << ",\n ";
+ OS << " Fixups:[";
+ for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
+ ie = DF->fixup_end(); it != ie; ++it) {
+ if (it != DF->fixup_begin()) OS << ",\n ";
+ OS << *it;
+ }
+ OS << "]";
+ }
+ break;
+ }
+ case MCFragment::FT_Fill: {
+ const MCFillFragment *FF = cast<MCFillFragment>(this);
+ OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
+ << " Size:" << FF->getSize();
+ break;
+ }
+ case MCFragment::FT_Inst: {
+ const MCInstFragment *IF = cast<MCInstFragment>(this);
+ OS << "\n ";
+ OS << " Inst:";
+ IF->getInst().dump_pretty(OS);
+ break;
+ }
+ case MCFragment::FT_Org: {
+ const MCOrgFragment *OF = cast<MCOrgFragment>(this);
+ OS << "\n ";
+ OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
+ break;
+ }
+ case MCFragment::FT_Dwarf: {
+ const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
+ OS << "\n ";
+ OS << " AddrDelta:" << OF->getAddrDelta()
+ << " LineDelta:" << OF->getLineDelta();
+ break;
+ }
+ case MCFragment::FT_DwarfFrame: {
+ const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
+ OS << "\n ";
+ OS << " AddrDelta:" << CF->getAddrDelta();
+ break;
+ }
+ case MCFragment::FT_LEB: {
+ const MCLEBFragment *LF = cast<MCLEBFragment>(this);
+ OS << "\n ";
+ OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
+ break;
+ }
+ }
+ OS << ">";
+}
+
+void MCSectionData::dump() {
+ raw_ostream &OS = llvm::errs();
+
+ OS << "<MCSectionData";
+ OS << " Alignment:" << getAlignment() << " Fragments:[\n ";
+ for (iterator it = begin(), ie = end(); it != ie; ++it) {
+ if (it != begin()) OS << ",\n ";
+ it->dump();
+ }
+ OS << "]>";
+}
+
+void MCSymbolData::dump() {
+ raw_ostream &OS = llvm::errs();
+
+ OS << "<MCSymbolData Symbol:" << getSymbol()
+ << " Fragment:" << getFragment() << " Offset:" << getOffset()
+ << " Flags:" << getFlags() << " Index:" << getIndex();
+ if (isCommon())
+ OS << " (common, size:" << getCommonSize()
+ << " align: " << getCommonAlignment() << ")";
+ if (isExternal())
+ OS << " (external)";
+ if (isPrivateExtern())
+ OS << " (private extern)";
+ OS << ">";
+}
+
+void MCAssembler::dump() {
+ raw_ostream &OS = llvm::errs();
+
+ OS << "<MCAssembler\n";
+ OS << " Sections:[\n ";
+ for (iterator it = begin(), ie = end(); it != ie; ++it) {
+ if (it != begin()) OS << ",\n ";
+ it->dump();
+ }
+ OS << "],\n";
+ OS << " Symbols:[";
+
+ for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
+ if (it != symbol_begin()) OS << ",\n ";
+ it->dump();
+ }
+ OS << "]>\n";
+}
+
+// anchors for MC*Fragment vtables
+void MCDataFragment::anchor() { }
+void MCInstFragment::anchor() { }
+void MCAlignFragment::anchor() { }
+void MCFillFragment::anchor() { }
+void MCOrgFragment::anchor() { }
+void MCLEBFragment::anchor() { }
+void MCDwarfLineAddrFragment::anchor() { }
+void MCDwarfCallFrameFragment::anchor() { }
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