#define DEBUG_TYPE "assembler"
#include "llvm/MC/MCAssembler.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDwarf.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/ADT/OwningPtr.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/LEB128.h"
+#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Target/TargetRegistry.h"
-#include "llvm/Target/TargetAsmBackend.h"
-
-// FIXME: Gross.
-#include "../Target/X86/X86FixupKinds.h"
-#include <vector>
using namespace llvm;
-STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
+namespace {
+namespace stats {
+STATISTIC(EmittedFragments, "Number of emitted assembler fragments - total");
+STATISTIC(EmittedRelaxableFragments,
+ "Number of emitted assembler fragments - relaxable");
+STATISTIC(EmittedDataFragments,
+ "Number of emitted assembler fragments - data");
+STATISTIC(EmittedCompactEncodedInstFragments,
+ "Number of emitted assembler fragments - compact encoded inst");
+STATISTIC(EmittedAlignFragments,
+ "Number of emitted assembler fragments - align");
+STATISTIC(EmittedFillFragments,
+ "Number of emitted assembler fragments - fill");
+STATISTIC(EmittedOrgFragments,
+ "Number of emitted assembler fragments - org");
+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
/* *** */
+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::isFragmentValid(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::invalidateFragmentsFrom(MCFragment *F) {
+ // If this fragment wasn't already valid, we don't need to do anything.
+ if (!isFragmentValid(F))
+ return;
+
+ // Otherwise, reset the last valid fragment to the previous fragment
+ // (if this is the first fragment, it will be NULL).
+ const MCSectionData &SD = *F->getParent();
+ LastValidFragment[&SD] = F->getPrevNode();
+}
+
+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 valid.
+ while (!isFragmentValid(F)) {
+ assert(Cur && "Layout bookkeeping error");
+ 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);
+}
+
+uint64_t MCAsmLayout::computeBundlePadding(const MCFragment *F,
+ uint64_t FOffset, uint64_t FSize) {
+ uint64_t BundleSize = Assembler.getBundleAlignSize();
+ assert(BundleSize > 0 &&
+ "computeBundlePadding should only be called if bundling is enabled");
+ uint64_t BundleMask = BundleSize - 1;
+ uint64_t OffsetInBundle = FOffset & BundleMask;
+ uint64_t EndOfFragment = OffsetInBundle + FSize;
+
+ // There are two kinds of bundling restrictions:
+ //
+ // 1) For alignToBundleEnd(), add padding to ensure that the fragment will
+ // *end* on a bundle boundary.
+ // 2) Otherwise, check if the fragment would cross a bundle boundary. If it
+ // would, add padding until the end of the bundle so that the fragment
+ // will start in a new one.
+ if (F->alignToBundleEnd()) {
+ // Three possibilities here:
+ //
+ // A) The fragment just happens to end at a bundle boundary, so we're good.
+ // B) The fragment ends before the current bundle boundary: pad it just
+ // enough to reach the boundary.
+ // C) The fragment ends after the current bundle boundary: pad it until it
+ // reaches the end of the next bundle boundary.
+ //
+ // Note: this code could be made shorter with some modulo trickery, but it's
+ // intentionally kept in its more explicit form for simplicity.
+ if (EndOfFragment == BundleSize)
+ return 0;
+ else if (EndOfFragment < BundleSize)
+ return BundleSize - EndOfFragment;
+ else { // EndOfFragment > BundleSize
+ return 2 * BundleSize - EndOfFragment;
+ }
+ } else if (EndOfFragment > BundleSize)
+ return BundleSize - OffsetInBundle;
+ else
+ return 0;
+}
+
+/* *** */
+
MCFragment::MCFragment() : Kind(FragmentType(~0)) {
}
+MCFragment::~MCFragment() {
+}
+
MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
- : Kind(_Kind),
- Parent(_Parent),
- FileSize(~UINT64_C(0))
+ : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
{
if (Parent)
Parent->getFragmentList().push_back(this);
}
-MCFragment::~MCFragment() {
+/* *** */
+
+MCEncodedFragment::~MCEncodedFragment() {
}
-uint64_t MCFragment::getAddress() const {
- assert(getParent() && "Missing Section!");
- return getParent()->getAddress() + Offset;
+/* *** */
+
+MCEncodedFragmentWithFixups::~MCEncodedFragmentWithFixups() {
}
/* *** */
MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
: Section(&_Section),
+ Ordinal(~UINT32_C(0)),
Alignment(1),
- Address(~UINT64_C(0)),
- Size(~UINT64_C(0)),
- FileSize(~UINT64_C(0)),
+ BundleLockState(NotBundleLocked), BundleGroupBeforeFirstInst(false),
HasInstructions(false)
{
if (A)
A->getSectionList().push_back(this);
}
+MCSectionData::iterator
+MCSectionData::getSubsectionInsertionPoint(unsigned Subsection) {
+ if (Subsection == 0 && SubsectionFragmentMap.empty())
+ return end();
+
+ SmallVectorImpl<std::pair<unsigned, MCFragment *> >::iterator MI =
+ std::lower_bound(SubsectionFragmentMap.begin(), SubsectionFragmentMap.end(),
+ std::make_pair(Subsection, (MCFragment *)0));
+ bool ExactMatch = false;
+ if (MI != SubsectionFragmentMap.end()) {
+ ExactMatch = MI->first == Subsection;
+ if (ExactMatch)
+ ++MI;
+ }
+ iterator IP;
+ if (MI == SubsectionFragmentMap.end())
+ IP = end();
+ else
+ IP = MI->second;
+ if (!ExactMatch && Subsection != 0) {
+ // The GNU as documentation claims that subsections have an alignment of 4,
+ // although this appears not to be the case.
+ MCFragment *F = new MCDataFragment();
+ SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
+ getFragmentList().insert(IP, F);
+ F->setParent(this);
+ }
+ return IP;
+}
+
/* *** */
MCSymbolData::MCSymbolData() : Symbol(0) {}
uint64_t _Offset, MCAssembler *A)
: Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
IsExternal(false), IsPrivateExtern(false),
- CommonSize(0), CommonAlign(0), Flags(0), Index(0)
+ CommonSize(0), SymbolSize(0), CommonAlign(0),
+ Flags(0), Index(0)
{
if (A)
A->getSymbolList().push_back(this);
/* *** */
-MCAssembler::MCAssembler(MCContext &_Context, TargetAsmBackend &_Backend,
- MCCodeEmitter &_Emitter, raw_ostream &_OS)
- : Context(_Context), Backend(_Backend), Emitter(_Emitter),
- OS(_OS), SubsectionsViaSymbols(false)
-{
+MCAssembler::MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
+ MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
+ raw_ostream &OS_)
+ : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
+ OS(OS_), BundleAlignSize(0), RelaxAll(false), NoExecStack(false),
+ SubsectionsViaSymbols(false), ELFHeaderEFlags(0) {
}
MCAssembler::~MCAssembler() {
}
-static bool isScatteredFixupFullyResolvedSimple(const MCAssembler &Asm,
- const MCAsmFixup &Fixup,
- const MCValue Target,
- const MCSection *BaseSection) {
- // The effective fixup address is
- // addr(atom(A)) + offset(A)
- // - addr(atom(B)) - offset(B)
- // - addr(<base symbol>) + <fixup offset from base symbol>
- // and the offsets are not relocatable, so the fixup is fully resolved when
- // addr(atom(A)) - addr(atom(B)) - addr(<base symbol>)) == 0.
- //
- // The simple (Darwin, except on x86_64) way of dealing with this was to
- // assume that any reference to a temporary symbol *must* be a temporary
- // symbol in the same atom, unless the sections differ. Therefore, any PCrel
- // relocation to a temporary symbol (in the same section) is fully
- // resolved. This also works in conjunction with absolutized .set, which
- // requires the compiler to use .set to absolutize the differences between
- // symbols which the compiler knows to be assembly time constants, so we don't
- // need to worry about consider symbol differences fully resolved.
-
- // Non-relative fixups are only resolved if constant.
- if (!BaseSection)
- return Target.isAbsolute();
-
- // Otherwise, relative fixups are only resolved if not a difference and the
- // target is a temporary in the same section.
- if (Target.isAbsolute() || Target.getSymB())
- return false;
-
- const MCSymbol *A = &Target.getSymA()->getSymbol();
- if (!A->isTemporary() || !A->isInSection() ||
- &A->getSection() != BaseSection)
- return false;
-
- return true;
+void MCAssembler::reset() {
+ Sections.clear();
+ Symbols.clear();
+ SectionMap.clear();
+ SymbolMap.clear();
+ IndirectSymbols.clear();
+ DataRegions.clear();
+ ThumbFuncs.clear();
+ RelaxAll = false;
+ NoExecStack = false;
+ SubsectionsViaSymbols = false;
+ ELFHeaderEFlags = 0;
+
+ // reset objects owned by us
+ getBackend().reset();
+ getEmitter().reset();
+ getWriter().reset();
}
-static bool isScatteredFixupFullyResolved(const MCAssembler &Asm,
- const MCAsmFixup &Fixup,
- const MCValue Target,
- const MCSymbolData *BaseSymbol) {
- // The effective fixup address is
- // addr(atom(A)) + offset(A)
- // - addr(atom(B)) - offset(B)
- // - addr(BaseSymbol) + <fixup offset from base symbol>
- // and the offsets are not relocatable, so the fixup is fully resolved when
- // addr(atom(A)) - addr(atom(B)) - addr(BaseSymbol) == 0.
- //
- // Note that "false" is almost always conservatively correct (it means we emit
- // a relocation which is unnecessary), except when it would force us to emit a
- // relocation which the target cannot encode.
-
- const MCSymbolData *A_Base = 0, *B_Base = 0;
- if (const MCSymbolRefExpr *A = Target.getSymA()) {
- // Modified symbol references cannot be resolved.
- if (A->getKind() != MCSymbolRefExpr::VK_None)
- return false;
-
- A_Base = Asm.getAtom(&Asm.getSymbolData(A->getSymbol()));
- if (!A_Base)
- return false;
- }
-
- if (const MCSymbolRefExpr *B = Target.getSymB()) {
- // Modified symbol references cannot be resolved.
- if (B->getKind() != MCSymbolRefExpr::VK_None)
- return false;
-
- B_Base = Asm.getAtom(&Asm.getSymbolData(B->getSymbol()));
- if (!B_Base)
- return false;
- }
-
- // If there is no base, A and B have to be the same atom for this fixup to be
- // fully resolved.
- if (!BaseSymbol)
- return A_Base == B_Base;
-
- // Otherwise, B must be missing and A must be the base.
- return !B_Base && BaseSymbol == A_Base;
-}
-
-bool MCAssembler::isSymbolLinkerVisible(const MCSymbolData *SD) const {
+bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
// Non-temporary labels should always be visible to the linker.
- if (!SD->getSymbol().isTemporary())
+ if (!Symbol.isTemporary())
return true;
// Absolute temporary labels are never visible.
- if (!SD->getFragment())
+ if (!Symbol.isInSection())
return false;
// Otherwise, check if the section requires symbols even for temporary labels.
- return getBackend().doesSectionRequireSymbols(
- SD->getFragment()->getParent()->getSection());
-}
-
-const MCSymbolData *MCAssembler::getAtomForAddress(const MCSectionData *Section,
- uint64_t Address) const {
- const MCSymbolData *Best = 0;
- for (MCAssembler::const_symbol_iterator it = symbol_begin(),
- ie = symbol_end(); it != ie; ++it) {
- // Ignore non-linker visible symbols.
- if (!isSymbolLinkerVisible(it))
- continue;
-
- // Ignore symbols not in the same section.
- if (!it->getFragment() || it->getFragment()->getParent() != Section)
- continue;
-
- // Otherwise, find the closest symbol preceding this address (ties are
- // resolved in favor of the last defined symbol).
- if (it->getAddress() <= Address &&
- (!Best || it->getAddress() >= Best->getAddress()))
- Best = it;
- }
-
- return Best;
+ return getBackend().doesSectionRequireSymbols(Symbol.getSection());
}
const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
// Linker visible symbols define atoms.
- if (isSymbolLinkerVisible(SD))
+ if (isSymbolLinkerVisible(SD->getSymbol()))
return SD;
// Absolute and undefined symbols have no defining atom.
if (!SD->getFragment())
return 0;
- // Otherwise, search by address.
- return getAtomForAddress(SD->getFragment()->getParent(), SD->getAddress());
+ // 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, MCAsmFixup &Fixup,
- MCDataFragment *DF,
+bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
+ const MCFixup &Fixup, const MCFragment *DF,
MCValue &Target, uint64_t &Value) const {
- if (!Fixup.Value->EvaluateAsRelocatable(Target, &Layout))
- llvm_report_error("expected relocatable expression");
+ ++stats::evaluateFixup;
+
+ if (!Fixup.getValue()->EvaluateAsRelocatable(Target, Layout))
+ getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
- // FIXME: How do non-scattered symbols work in ELF? I presume the linker
- // doesn't support small relocations, but then under what criteria does the
- // assembler allow symbol differences?
+ 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();
- bool IsPCRel =
- Emitter.getFixupKindInfo(Fixup.Kind).Flags & MCFixupKindInfo::FKF_IsPCRel;
- bool IsResolved = true;
if (const MCSymbolRefExpr *A = Target.getSymA()) {
- if (A->getSymbol().isDefined())
- Value += getSymbolData(A->getSymbol()).getAddress();
- else
- IsResolved = false;
+ const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value += Layout.getSymbolOffset(&getSymbolData(Sym));
}
if (const MCSymbolRefExpr *B = Target.getSymB()) {
- if (B->getSymbol().isDefined())
- Value -= getSymbolData(B->getSymbol()).getAddress();
- else
- IsResolved = false;
+ const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
}
- // If we are using scattered symbols, determine whether this value is actually
- // resolved; scattering may cause atoms to move.
- if (IsResolved && getBackend().hasScatteredSymbols()) {
- if (getBackend().hasReliableSymbolDifference()) {
- // If this is a PCrel relocation, find the base atom (identified by its
- // symbol) that the fixup value is relative to.
- const MCSymbolData *BaseSymbol = 0;
- if (IsPCRel) {
- BaseSymbol = getAtomForAddress(
- DF->getParent(), DF->getAddress() + Fixup.Offset);
- if (!BaseSymbol)
- IsResolved = false;
- }
- if (IsResolved)
- IsResolved = isScatteredFixupFullyResolved(*this, Fixup, Target,
- BaseSymbol);
- } else {
- const MCSection *BaseSection = 0;
- if (IsPCRel)
- BaseSection = &DF->getParent()->getSection();
+ bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
+ MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
+ assert((ShouldAlignPC ? IsPCRel : true) &&
+ "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
- IsResolved = isScatteredFixupFullyResolvedSimple(*this, Fixup, Target,
- BaseSection);
- }
+ 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;
}
- if (IsPCRel)
- Value -= DF->getAddress() + Fixup.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;
}
-void MCAssembler::LayoutSection(MCSectionData &SD,
- MCAsmLayout &Layout) {
- uint64_t Address = SD.getAddress();
-
- for (MCSectionData::iterator it = SD.begin(), ie = SD.end(); it != ie; ++it) {
- MCFragment &F = *it;
-
- F.setOffset(Address - SD.getAddress());
-
- // Evaluate fragment size.
- switch (F.getKind()) {
- case MCFragment::FT_Align: {
- MCAlignFragment &AF = cast<MCAlignFragment>(F);
-
- uint64_t Size = OffsetToAlignment(Address, AF.getAlignment());
- if (Size > AF.getMaxBytesToEmit())
- AF.setFileSize(0);
- else
- AF.setFileSize(Size);
- break;
- }
+uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
+ const MCFragment &F) const {
+ switch (F.getKind()) {
+ case MCFragment::FT_Data:
+ case MCFragment::FT_Relaxable:
+ case MCFragment::FT_CompactEncodedInst:
+ return cast<MCEncodedFragment>(F).getContents().size();
+ case MCFragment::FT_Fill:
+ return cast<MCFillFragment>(F).getSize();
- case MCFragment::FT_Data:
- F.setFileSize(cast<MCDataFragment>(F).getContents().size());
- break;
+ case MCFragment::FT_LEB:
+ return cast<MCLEBFragment>(F).getContents().size();
- case MCFragment::FT_Fill: {
- MCFillFragment &FF = cast<MCFillFragment>(F);
- F.setFileSize(FF.getValueSize() * FF.getCount());
- break;
+ case MCFragment::FT_Align: {
+ const MCAlignFragment &AF = cast<MCAlignFragment>(F);
+ unsigned Offset = Layout.getFragmentOffset(&AF);
+ unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
+ // If we are padding with nops, force the padding to be larger than the
+ // minimum nop size.
+ if (Size > 0 && AF.hasEmitNops()) {
+ while (Size % getBackend().getMinimumNopSize())
+ Size += AF.getAlignment();
}
+ if (Size > AF.getMaxBytesToEmit())
+ return 0;
+ return Size;
+ }
- case MCFragment::FT_Org: {
- MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ case MCFragment::FT_Org: {
+ const 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;
+ }
- int64_t TargetLocation;
- if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, &Layout))
- llvm_report_error("expected assembly-time absolute expression");
+ case MCFragment::FT_Dwarf:
+ return cast<MCDwarfLineAddrFragment>(F).getContents().size();
+ case MCFragment::FT_DwarfFrame:
+ return cast<MCDwarfCallFrameFragment>(F).getContents().size();
+ }
- // FIXME: We need a way to communicate this error.
- int64_t Offset = TargetLocation - F.getOffset();
- if (Offset < 0)
- llvm_report_error("invalid .org offset '" + Twine(TargetLocation) +
- "' (at offset '" + Twine(F.getOffset()) + "'");
+ llvm_unreachable("invalid fragment kind");
+}
- F.setFileSize(Offset);
- break;
- }
+void MCAsmLayout::layoutFragment(MCFragment *F) {
+ MCFragment *Prev = F->getPrevNode();
- case MCFragment::FT_ZeroFill: {
- MCZeroFillFragment &ZFF = cast<MCZeroFillFragment>(F);
+ // We should never try to recompute something which is valid.
+ assert(!isFragmentValid(F) && "Attempt to recompute a valid fragment!");
+ // We should never try to compute the fragment layout if its predecessor
+ // isn't valid.
+ assert((!Prev || isFragmentValid(Prev)) &&
+ "Attempt to compute fragment before its predecessor!");
- // Align the fragment offset; it is safe to adjust the offset freely since
- // this is only in virtual sections.
- Address = RoundUpToAlignment(Address, ZFF.getAlignment());
- F.setOffset(Address - SD.getAddress());
+ ++stats::FragmentLayouts;
- // FIXME: This is misnamed.
- F.setFileSize(ZFF.getSize());
- break;
- }
- }
+ // Compute fragment offset and size.
+ if (Prev)
+ F->Offset = Prev->Offset + getAssembler().computeFragmentSize(*this, *Prev);
+ else
+ F->Offset = 0;
+ LastValidFragment[F->getParent()] = F;
- Address += F.getFileSize();
+ // If bundling is enabled and this fragment has instructions in it, it has to
+ // obey the bundling restrictions. With padding, we'll have:
+ //
+ //
+ // BundlePadding
+ // |||
+ // -------------------------------------
+ // Prev |##########| F |
+ // -------------------------------------
+ // ^
+ // |
+ // F->Offset
+ //
+ // The fragment's offset will point to after the padding, and its computed
+ // size won't include the padding.
+ //
+ if (Assembler.isBundlingEnabled() && F->hasInstructions()) {
+ assert(isa<MCEncodedFragment>(F) &&
+ "Only MCEncodedFragment implementations have instructions");
+ uint64_t FSize = Assembler.computeFragmentSize(*this, *F);
+
+ if (FSize > Assembler.getBundleAlignSize())
+ report_fatal_error("Fragment can't be larger than a bundle size");
+
+ uint64_t RequiredBundlePadding = computeBundlePadding(F, F->Offset, FSize);
+ if (RequiredBundlePadding > UINT8_MAX)
+ report_fatal_error("Padding cannot exceed 255 bytes");
+ F->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
+ F->Offset += RequiredBundlePadding;
}
+}
- // Set the section sizes.
- SD.setSize(Address - SD.getAddress());
- if (getBackend().isVirtualSection(SD.getSection()))
- SD.setFileSize(0);
- else
- SD.setFileSize(Address - SD.getAddress());
-}
-
-/// WriteNopData - Write optimal nops to the output file for the \arg Count
-/// bytes. This returns the number of bytes written. It may return 0 if
-/// the \arg Count is more than the maximum optimal nops.
-///
-/// FIXME this is X86 32-bit specific and should move to a better place.
-static uint64_t WriteNopData(uint64_t Count, MCObjectWriter *OW) {
- static const uint8_t Nops[16][16] = {
- // nop
- {0x90},
- // xchg %ax,%ax
- {0x66, 0x90},
- // nopl (%[re]ax)
- {0x0f, 0x1f, 0x00},
- // nopl 0(%[re]ax)
- {0x0f, 0x1f, 0x40, 0x00},
- // nopl 0(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopw 0(%[re]ax,%[re]ax,1)
- {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopl 0L(%[re]ax)
- {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
- // nopl 0L(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
- // nopw 0L(%[re]ax,%[re]ax,1)
- {0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
- // nopw %cs:0L(%[re]ax,%[re]ax,1)
- {0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
- // nopl 0(%[re]ax,%[re]ax,1)
- // nopw 0(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x44, 0x00, 0x00,
- 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopw 0(%[re]ax,%[re]ax,1)
- // nopw 0(%[re]ax,%[re]ax,1)
- {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
- 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopw 0(%[re]ax,%[re]ax,1)
- // nopl 0L(%[re]ax) */
- {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
- 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
- // nopl 0L(%[re]ax)
- // nopl 0L(%[re]ax)
- {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
- 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
- // nopl 0L(%[re]ax)
- // nopl 0L(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
- 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00}
- };
-
- if (Count > 15)
- return 0;
+/// \brief Write the contents of a fragment to the given object writer. Expects
+/// a MCEncodedFragment.
+static void writeFragmentContents(const MCFragment &F, MCObjectWriter *OW) {
+ const MCEncodedFragment &EF = cast<MCEncodedFragment>(F);
+ OW->WriteBytes(EF.getContents());
+}
- for (uint64_t i = 0; i < Count; i++)
- OW->Write8(uint8_t(Nops[Count - 1][i]));
+/// \brief Write the fragment \p F to the output file.
+static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment &F) {
+ MCObjectWriter *OW = &Asm.getWriter();
- return Count;
-}
+ // FIXME: Embed in fragments instead?
+ uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
+
+ // Should NOP padding be written out before this fragment?
+ unsigned BundlePadding = F.getBundlePadding();
+ if (BundlePadding > 0) {
+ assert(Asm.isBundlingEnabled() &&
+ "Writing bundle padding with disabled bundling");
+ assert(F.hasInstructions() &&
+ "Writing bundle padding for a fragment without instructions");
+
+ unsigned TotalLength = BundlePadding + static_cast<unsigned>(FragmentSize);
+ if (F.alignToBundleEnd() && TotalLength > Asm.getBundleAlignSize()) {
+ // If the padding itself crosses a bundle boundary, it must be emitted
+ // in 2 pieces, since even nop instructions must not cross boundaries.
+ // v--------------v <- BundleAlignSize
+ // v---------v <- BundlePadding
+ // ----------------------------
+ // | Prev |####|####| F |
+ // ----------------------------
+ // ^-------------------^ <- TotalLength
+ unsigned DistanceToBoundary = TotalLength - Asm.getBundleAlignSize();
+ if (!Asm.getBackend().writeNopData(DistanceToBoundary, OW))
+ report_fatal_error("unable to write NOP sequence of " +
+ Twine(DistanceToBoundary) + " bytes");
+ BundlePadding -= DistanceToBoundary;
+ }
+ if (!Asm.getBackend().writeNopData(BundlePadding, OW))
+ report_fatal_error("unable to write NOP sequence of " +
+ Twine(BundlePadding) + " bytes");
+ }
-/// WriteFragmentData - Write the \arg F data to the output file.
-static void WriteFragmentData(const MCFragment &F, MCObjectWriter *OW) {
+ // This variable (and its dummy usage) is to participate in the assert at
+ // the end of the function.
uint64_t Start = OW->getStream().tell();
(void) Start;
- ++EmittedFragments;
+ ++stats::EmittedFragments;
- // FIXME: Embed in fragments instead?
switch (F.getKind()) {
case MCFragment::FT_Align: {
- MCAlignFragment &AF = cast<MCAlignFragment>(F);
- uint64_t Count = AF.getFileSize() / AF.getValueSize();
+ ++stats::EmittedAlignFragments;
+ const MCAlignFragment &AF = cast<MCAlignFragment>(F);
+ assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
+
+ uint64_t Count = FragmentSize / AF.getValueSize();
// 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() != AF.getFileSize())
- llvm_report_error("undefined .align directive, value size '" +
+ if (Count * AF.getValueSize() != FragmentSize)
+ report_fatal_error("undefined .align directive, value size '" +
Twine(AF.getValueSize()) +
"' is not a divisor of padding size '" +
- Twine(AF.getFileSize()) + "'");
+ 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 (AF.getEmitNops()) {
- uint64_t NopByteCount = WriteNopData(Count, OW);
- Count -= NopByteCount;
+ // bytes left to fill use 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:
- assert(0 && "Invalid size!");
+ 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;
break;
}
- case MCFragment::FT_Data: {
- OW->WriteBytes(cast<MCDataFragment>(F).getContents().str());
+ case MCFragment::FT_Data:
+ ++stats::EmittedDataFragments;
+ writeFragmentContents(F, OW);
+ break;
+
+ case MCFragment::FT_Relaxable:
+ ++stats::EmittedRelaxableFragments;
+ writeFragmentContents(F, OW);
+ break;
+
+ case MCFragment::FT_CompactEncodedInst:
+ ++stats::EmittedCompactEncodedInstFragments;
+ writeFragmentContents(F, OW);
break;
- }
case MCFragment::FT_Fill: {
- MCFillFragment &FF = cast<MCFillFragment>(F);
- for (uint64_t i = 0, e = FF.getCount(); i != e; ++i) {
+ ++stats::EmittedFillFragments;
+ const 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:
- assert(0 && "Invalid size!");
+ 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;
break;
}
+ case MCFragment::FT_LEB: {
+ const MCLEBFragment &LF = cast<MCLEBFragment>(F);
+ OW->WriteBytes(LF.getContents().str());
+ break;
+ }
+
case MCFragment::FT_Org: {
- MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ ++stats::EmittedOrgFragments;
+ const MCOrgFragment &OF = cast<MCOrgFragment>(F);
- for (uint64_t i = 0, e = OF.getFileSize(); i != e; ++i)
+ for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
OW->Write8(uint8_t(OF.getValue()));
break;
}
- case MCFragment::FT_ZeroFill: {
- assert(0 && "Invalid zero fill fragment in concrete section!");
+ 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 == F.getFileSize());
+ assert(OW->getStream().tell() - Start == FragmentSize &&
+ "The stream should advance by fragment size");
}
-void MCAssembler::WriteSectionData(const MCSectionData *SD,
- MCObjectWriter *OW) const {
+void MCAssembler::writeSectionData(const MCSectionData *SD,
+ const MCAsmLayout &Layout) const {
// Ignore virtual sections.
- if (getBackend().isVirtualSection(SD->getSection())) {
- assert(SD->getFileSize() == 0);
+ 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.
+ const 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() == 0 ||
+ cast<MCAlignFragment>(it)->getValue() == 0) &&
+ "Invalid align in virtual section!");
+ break;
+ case MCFragment::FT_Fill:
+ assert((cast<MCFillFragment>(it)->getValueSize() == 0 ||
+ cast<MCFillFragment>(it)->getValue() == 0) &&
+ "Invalid fill in virtual section!");
+ break;
+ }
+ }
+
return;
}
- uint64_t Start = OW->getStream().tell();
- (void) Start;
+ uint64_t Start = getWriter().getStream().tell();
+ (void)Start;
+
+ for (MCSectionData::const_iterator it = SD->begin(), ie = SD->end();
+ it != ie; ++it)
+ writeFragment(*this, Layout, *it);
- for (MCSectionData::const_iterator it = SD->begin(),
- ie = SD->end(); it != ie; ++it)
- WriteFragmentData(*it, OW);
+ assert(getWriter().getStream().tell() - Start ==
+ Layout.getSectionAddressSize(SD));
+}
- // Add section padding.
- assert(SD->getFileSize() >= SD->getSize() && "Invalid section sizes!");
- OW->WriteZeros(SD->getFileSize() - SD->getSize());
- assert(OW->getStream().tell() - Start == SD->getFileSize());
+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() {
llvm::errs() << "assembler backend - pre-layout\n--\n";
dump(); });
- // Layout until everything fits.
+ // Create the layout object.
MCAsmLayout Layout(*this);
- while (LayoutOnce(Layout))
+
+ // 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 iFrag = SD->begin(), iFragEnd = SD->end();
+ iFrag != iFragEnd; ++iFrag)
+ iFrag->setLayoutOrder(FragmentIndex++);
+ }
+
+ // Layout until everything fits.
+ while (layoutOnce(Layout))
continue;
DEBUG_WITH_TYPE("mc-dump", {
- llvm::errs() << "assembler backend - post-layout\n--\n";
+ 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(); });
- llvm::OwningPtr<MCObjectWriter> Writer(getBackend().createObjectWriter(OS));
- if (!Writer)
- llvm_report_error("unable to create object writer!");
+ 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).
- Writer->ExecutePostLayoutBinding(*this);
+ 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)
- continue;
-
- for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
- ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
- MCAsmFixup &Fixup = *it3;
-
- // Evaluate the fixup.
- MCValue Target;
- uint64_t FixedValue;
- if (!EvaluateFixup(Layout, Fixup, DF, 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.
- Writer->RecordRelocation(*this, DF, Fixup, Target, FixedValue);
+ MCEncodedFragmentWithFixups *F =
+ dyn_cast<MCEncodedFragmentWithFixups>(it2);
+ if (F) {
+ for (MCEncodedFragmentWithFixups::fixup_iterator it3 = F->fixup_begin(),
+ ie3 = F->fixup_end(); it3 != ie3; ++it3) {
+ MCFixup &Fixup = *it3;
+ uint64_t FixedValue = handleFixup(Layout, *F, Fixup);
+ getBackend().applyFixup(Fixup, F->getContents().data(),
+ F->getContents().size(), FixedValue);
}
-
- getBackend().ApplyFixup(Fixup, *DF, FixedValue);
}
}
}
// Write the object file.
- Writer->WriteObject(*this);
- OS.flush();
+ getWriter().WriteObject(*this, Layout);
+
+ stats::ObjectBytes += OS.tell() - StartOffset;
}
-bool MCAssembler::FixupNeedsRelaxation(MCAsmFixup &Fixup, MCDataFragment *DF,
+bool MCAssembler::fixupNeedsRelaxation(const MCFixup &Fixup,
+ const MCRelaxableFragment *DF,
const MCAsmLayout &Layout) const {
- // Currently we only need to relax X86::reloc_pcrel_1byte.
- if (unsigned(Fixup.Kind) != X86::reloc_pcrel_1byte)
- return false;
-
// If we cannot resolve the fixup value, it requires relaxation.
MCValue Target;
uint64_t Value;
- if (!EvaluateFixup(Layout, Fixup, DF, Target, Value))
+ if (!evaluateFixup(Layout, Fixup, DF, Target, Value))
return true;
- // Otherwise, relax if the value is too big for a (signed) i8.
- return int64_t(Value) != int64_t(int8_t(Value));
+ return getBackend().fixupNeedsRelaxation(Fixup, Value, DF, Layout);
}
-bool MCAssembler::LayoutOnce(MCAsmLayout &Layout) {
- // Layout the concrete sections and fragments.
- uint64_t Address = 0;
- MCSectionData *Prev = 0;
- for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
+bool MCAssembler::fragmentNeedsRelaxation(const MCRelaxableFragment *F,
+ 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(F->getInst()))
+ return false;
- // Skip virtual sections.
- if (getBackend().isVirtualSection(SD.getSection()))
- continue;
+ for (MCRelaxableFragment::const_fixup_iterator it = F->fixup_begin(),
+ ie = F->fixup_end(); it != ie; ++it)
+ if (fixupNeedsRelaxation(*it, F, Layout))
+ return true;
- // Align this section if necessary by adding padding bytes to the previous
- // section.
- if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment())) {
- assert(Prev && "Missing prev section!");
- Prev->setFileSize(Prev->getFileSize() + Pad);
- Address += Pad;
- }
+ return false;
+}
- // Layout the section fragments and its size.
- SD.setAddress(Address);
- LayoutSection(SD, Layout);
- Address += SD.getFileSize();
+bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
+ MCRelaxableFragment &F) {
+ if (!fragmentNeedsRelaxation(&F, Layout))
+ return false;
- Prev = &SD;
- }
+ ++stats::RelaxedInstructions;
- // Layout the virtual sections.
- for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
+ // 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(F.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 fragment.
+ F.setInst(Relaxed);
+ F.getContents() = Code;
+ F.getFixups() = Fixups;
+
+ 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())
+ encodeSLEB128(Value, OSE);
+ else
+ encodeULEB128(Value, OSE);
+ OSE.flush();
+ return OldSize != LF.getContents().size();
+}
- if (!getBackend().isVirtualSection(SD.getSection()))
- continue;
+bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
+ MCDwarfLineAddrFragment &DF) {
+ MCContext &Context = Layout.getAssembler().getContext();
+ 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(Context, LineDelta, AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
- // Align this section if necessary by adding padding bytes to the previous
- // section.
- if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment()))
- Address += Pad;
+bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
+ MCDwarfCallFrameFragment &DF) {
+ MCContext &Context = Layout.getAssembler().getContext();
+ 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(Context, AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
- SD.setAddress(Address);
- LayoutSection(SD, Layout);
- Address += SD.getSize();
+bool MCAssembler::layoutSectionOnce(MCAsmLayout &Layout, MCSectionData &SD) {
+ // Holds the first fragment which needed relaxing during this layout. It will
+ // remain NULL if none were relaxed.
+ // When a fragment is relaxed, all the fragments following it should get
+ // invalidated because their offset is going to change.
+ MCFragment *FirstRelaxedFragment = NULL;
+
+ // Attempt to relax all the fragments in the section.
+ for (MCSectionData::iterator I = SD.begin(), IE = SD.end(); I != IE; ++I) {
+ // Check if this is a fragment that needs relaxation.
+ bool RelaxedFrag = false;
+ switch(I->getKind()) {
+ default:
+ break;
+ case MCFragment::FT_Relaxable:
+ assert(!getRelaxAll() &&
+ "Did not expect a MCRelaxableFragment in RelaxAll mode");
+ RelaxedFrag = relaxInstruction(Layout, *cast<MCRelaxableFragment>(I));
+ break;
+ case MCFragment::FT_Dwarf:
+ RelaxedFrag = relaxDwarfLineAddr(Layout,
+ *cast<MCDwarfLineAddrFragment>(I));
+ break;
+ case MCFragment::FT_DwarfFrame:
+ RelaxedFrag =
+ relaxDwarfCallFrameFragment(Layout,
+ *cast<MCDwarfCallFrameFragment>(I));
+ break;
+ case MCFragment::FT_LEB:
+ RelaxedFrag = relaxLEB(Layout, *cast<MCLEBFragment>(I));
+ break;
+ }
+ if (RelaxedFrag && !FirstRelaxedFragment)
+ FirstRelaxedFragment = I;
}
+ if (FirstRelaxedFragment) {
+ Layout.invalidateFragmentsFrom(FirstRelaxedFragment);
+ return true;
+ }
+ return false;
+}
+
+bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
+ ++stats::RelaxationSteps;
- // Scan the fixups in order and relax any that don't fit.
+ bool WasRelaxed = false;
for (iterator it = begin(), ie = end(); it != ie; ++it) {
MCSectionData &SD = *it;
+ while (layoutSectionOnce(Layout, SD))
+ WasRelaxed = true;
+ }
- for (MCSectionData::iterator it2 = SD.begin(),
- ie2 = SD.end(); it2 != ie2; ++it2) {
- MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
- if (!DF)
- continue;
-
- for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
- ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
- MCAsmFixup &Fixup = *it3;
-
- // Check whether we need to relax this fixup.
- if (!FixupNeedsRelaxation(Fixup, DF, Layout))
- continue;
-
- // Relax the instruction.
- //
- // FIXME: This is a huge temporary hack which just looks for x86
- // branches; the only thing we need to relax on x86 is
- // 'X86::reloc_pcrel_1byte'. Once we have MCInst fragments, this will be
- // replaced by a TargetAsmBackend hook (most likely tblgen'd) to relax
- // an individual MCInst.
- SmallVectorImpl<char> &C = DF->getContents();
- uint64_t PrevOffset = Fixup.Offset;
- unsigned Amt = 0;
-
- // jcc instructions
- if (unsigned(C[Fixup.Offset-1]) >= 0x70 &&
- unsigned(C[Fixup.Offset-1]) <= 0x7f) {
- C[Fixup.Offset] = C[Fixup.Offset-1] + 0x10;
- C[Fixup.Offset-1] = char(0x0f);
- ++Fixup.Offset;
- Amt = 4;
-
- // jmp rel8
- } else if (C[Fixup.Offset-1] == char(0xeb)) {
- C[Fixup.Offset-1] = char(0xe9);
- Amt = 3;
-
- } else
- llvm_unreachable("unknown 1 byte pcrel instruction!");
-
- Fixup.Value = MCBinaryExpr::Create(
- MCBinaryExpr::Sub, Fixup.Value,
- MCConstantExpr::Create(3, getContext()),
- getContext());
- C.insert(C.begin() + Fixup.Offset, Amt, char(0));
- Fixup.Kind = MCFixupKind(X86::reloc_pcrel_4byte);
-
- // Update the remaining fixups, which have slid.
- //
- // FIXME: This is bad for performance, but will be eliminated by the
- // move to MCInst specific fragments.
- ++it3;
- for (; it3 != ie3; ++it3)
- it3->Offset += Amt;
-
- // Update all the symbols for this fragment, which may have slid.
- //
- // FIXME: This is really really bad for performance, but will be
- // eliminated by the move to MCInst specific fragments.
- for (MCAssembler::symbol_iterator it = symbol_begin(),
- ie = symbol_end(); it != ie; ++it) {
- MCSymbolData &SD = *it;
-
- if (it->getFragment() != DF)
- continue;
-
- if (SD.getOffset() > PrevOffset)
- SD.setOffset(SD.getOffset() + Amt);
- }
+ return WasRelaxed;
+}
- // Restart layout.
- //
- // FIXME: This is O(N^2), but will be eliminated once we have a smart
- // MCAsmLayout object.
- return true;
- }
- }
+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());
}
-
- return false;
}
// Debugging methods
namespace llvm {
-raw_ostream &operator<<(raw_ostream &OS, const MCAsmFixup &AF) {
- OS << "<MCAsmFixup" << " Offset:" << AF.Offset << " Value:" << *AF.Value
- << " Kind:" << AF.Kind << ">";
+raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
+ OS << "<MCFixup" << " Offset:" << AF.getOffset()
+ << " Value:" << *AF.getValue()
+ << " Kind:" << AF.getKind() << ">";
return OS;
}
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void MCFragment::dump() {
raw_ostream &OS = llvm::errs();
- OS << "<MCFragment " << (void*) this << " Offset:" << Offset
- << " FileSize:" << FileSize;
-
- OS << ">";
-}
-
-void MCAlignFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCAlignFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Alignment:" << getAlignment()
- << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " MaxBytesToEmit:" << getMaxBytesToEmit() << ">";
-}
+ OS << "<";
+ switch (getKind()) {
+ case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
+ case MCFragment::FT_Data: OS << "MCDataFragment"; break;
+ case MCFragment::FT_CompactEncodedInst:
+ OS << "MCCompactEncodedInstFragment"; break;
+ case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
+ case MCFragment::FT_Relaxable: OS << "MCRelaxableFragment"; 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;
+ }
-void MCDataFragment::dump() {
- raw_ostream &OS = llvm::errs();
+ OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
+ << " Offset:" << Offset
+ << " HasInstructions:" << hasInstructions()
+ << " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
- OS << "<MCDataFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Contents:[";
- for (unsigned i = 0, e = getContents().size(); i != e; ++i) {
- if (i) OS << ",";
- OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
- }
- OS << "] (" << getContents().size() << " bytes)";
-
- if (!getFixups().empty()) {
- OS << ",\n ";
- OS << " Fixups:[";
- for (fixup_iterator it = fixup_begin(), ie = fixup_end(); it != ie; ++it) {
- if (it != fixup_begin()) OS << ",\n ";
- OS << *it;
+ 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 << "]";
+ OS << "] (" << Contents.size() << " bytes)";
+
+ if (DF->fixup_begin() != DF->fixup_end()) {
+ 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_CompactEncodedInst: {
+ const MCCompactEncodedInstFragment *CEIF =
+ cast<MCCompactEncodedInstFragment>(this);
+ OS << "\n ";
+ OS << " Contents:[";
+ const SmallVectorImpl<char> &Contents = CEIF->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)";
+ 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_Relaxable: {
+ const MCRelaxableFragment *F = cast<MCRelaxableFragment>(this);
+ OS << "\n ";
+ OS << " Inst:";
+ F->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 MCFillFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCFillFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " Count:" << getCount() << ">";
-}
-
-void MCOrgFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCOrgFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Offset:" << getOffset() << " Value:" << getValue() << ">";
-}
-
-void MCZeroFillFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCZeroFillFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Size:" << getSize() << " Alignment:" << getAlignment() << ">";
-}
-
void MCSectionData::dump() {
raw_ostream &OS = llvm::errs();
OS << "<MCSectionData";
- OS << " Alignment:" << getAlignment() << " Address:" << Address
- << " Size:" << Size << " FileSize:" << FileSize
+ OS << " Alignment:" << getAlignment()
<< " Fragments:[\n ";
for (iterator it = begin(), ie = end(); it != ie; ++it) {
if (it != begin()) OS << ",\n ";
}
OS << "]>\n";
}
+#endif
+
+// anchors for MC*Fragment vtables
+void MCEncodedFragment::anchor() { }
+void MCEncodedFragmentWithFixups::anchor() { }
+void MCDataFragment::anchor() { }
+void MCCompactEncodedInstFragment::anchor() { }
+void MCRelaxableFragment::anchor() { }
+void MCAlignFragment::anchor() { }
+void MCFillFragment::anchor() { }
+void MCOrgFragment::anchor() { }
+void MCLEBFragment::anchor() { }
+void MCDwarfLineAddrFragment::anchor() { }
+void MCDwarfCallFrameFragment::anchor() { }
projects / oota-llvm.git / blobdiff