//
//===----------------------------------------------------------------------===//
-#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/MCAsmInfo.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/MCSectionELF.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/Target/TargetRegistry.h"
-#include "llvm/Target/TargetAsmBackend.h"
-
-#include <vector>
+#include <tuple>
using namespace llvm;
+#define DEBUG_TYPE "assembler"
+
namespace {
namespace stats {
-STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
-STATISTIC(EvaluateFixup, "Number of evaluated fixups");
+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");
-STATISTIC(SectionLayouts, "Number of section layouts");
}
}
/* *** */
-MCAsmLayout::MCAsmLayout(MCAssembler &Asm) : Assembler(Asm) {
+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 (!Asm.getBackend().isVirtualSection(it->getSection()))
+ if (!it->isVirtualSection())
SectionOrder.push_back(&*it);
for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
- if (Asm.getBackend().isVirtualSection(it->getSection()))
+ if (it->isVirtualSection())
SectionOrder.push_back(&*it);
}
-void MCAsmLayout::UpdateForSlide(MCFragment *F, int SlideAmount) {
- // We shouldn't have to do anything special to support negative slides, and it
- // is a perfectly valid thing to do as long as other parts of the system can
- // guarantee convergence.
- assert(SlideAmount >= 0 && "Negative slides not yet supported");
-
- // Update the layout by simply recomputing the layout for the entire
- // file. This is trivially correct, but very slow.
- //
- // FIXME-PERF: This is O(N^2), but will be eliminated once we get smarter.
-
- // Layout the sections in order.
- LayoutFile();
+bool MCAsmLayout::isFragmentValid(const MCFragment *F) const {
+ const MCSection *Sec = F->getParent();
+ const MCFragment *LastValid = LastValidFragment.lookup(Sec);
+ if (!LastValid)
+ return false;
+ assert(LastValid->getParent() == Sec);
+ return F->getLayoutOrder() <= LastValid->getLayoutOrder();
}
-void MCAsmLayout::FragmentReplaced(MCFragment *Src, MCFragment *Dst) {
- Dst->Offset = Src->Offset;
- Dst->EffectiveSize = Src->EffectiveSize;
-}
+void MCAsmLayout::invalidateFragmentsFrom(MCFragment *F) {
+ // If this fragment wasn't already valid, we don't need to do anything.
+ if (!isFragmentValid(F))
+ return;
-uint64_t MCAsmLayout::getFragmentAddress(const MCFragment *F) const {
- assert(F->getParent() && "Missing section()!");
- return getSectionAddress(F->getParent()) + getFragmentOffset(F);
+ // Otherwise, reset the last valid fragment to the previous fragment
+ // (if this is the first fragment, it will be NULL).
+ LastValidFragment[F->getParent()] = F->getPrevNode();
}
-uint64_t MCAsmLayout::getFragmentEffectiveSize(const MCFragment *F) const {
- assert(F->EffectiveSize != ~UINT64_C(0) && "Address not set!");
- return F->EffectiveSize;
+void MCAsmLayout::ensureValid(const MCFragment *F) const {
+ MCSection *Sec = F->getParent();
+ MCFragment *Cur = LastValidFragment[Sec];
+ if (!Cur)
+ Cur = Sec->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::getSymbolAddress(const MCSymbolData *SD) const {
- assert(SD->getFragment() && "Invalid getAddress() on undefined symbol!");
- return getFragmentAddress(SD->getFragment()) + SD->getOffset();
+// Simple getSymbolOffset helper for the non-varibale case.
+static bool getLabelOffset(const MCAsmLayout &Layout, const MCSymbol &S,
+ bool ReportError, uint64_t &Val) {
+ if (!S.getFragment()) {
+ if (ReportError)
+ report_fatal_error("unable to evaluate offset to undefined symbol '" +
+ S.getName() + "'");
+ return false;
+ }
+ Val = Layout.getFragmentOffset(S.getFragment()) + S.getOffset();
+ return true;
}
-uint64_t MCAsmLayout::getSectionAddress(const MCSectionData *SD) const {
- assert(SD->Address != ~UINT64_C(0) && "Address not set!");
- return SD->Address;
+static bool getSymbolOffsetImpl(const MCAsmLayout &Layout, const MCSymbol &S,
+ bool ReportError, uint64_t &Val) {
+ if (!S.isVariable())
+ return getLabelOffset(Layout, S, ReportError, Val);
+
+ // If SD is a variable, evaluate it.
+ MCValue Target;
+ if (!S.getVariableValue()->EvaluateAsRelocatable(Target, &Layout, nullptr))
+ report_fatal_error("unable to evaluate offset for variable '" +
+ S.getName() + "'");
+
+ uint64_t Offset = Target.getConstant();
+
+ const MCSymbolRefExpr *A = Target.getSymA();
+ if (A) {
+ uint64_t ValA;
+ if (!getLabelOffset(Layout, A->getSymbol(), ReportError, ValA))
+ return false;
+ Offset += ValA;
+ }
+
+ const MCSymbolRefExpr *B = Target.getSymB();
+ if (B) {
+ uint64_t ValB;
+ if (!getLabelOffset(Layout, B->getSymbol(), ReportError, ValB))
+ return false;
+ Offset -= ValB;
+ }
+
+ Val = Offset;
+ return true;
}
-uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
+bool MCAsmLayout::getSymbolOffset(const MCSymbol &S, uint64_t &Val) const {
+ return getSymbolOffsetImpl(*this, S, false, Val);
+}
+
+uint64_t MCAsmLayout::getSymbolOffset(const MCSymbol &S) const {
+ uint64_t Val;
+ getSymbolOffsetImpl(*this, S, true, Val);
+ return Val;
+}
+
+const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
+ if (!Symbol.isVariable())
+ return &Symbol;
+
+ const MCExpr *Expr = Symbol.getVariableValue();
+ MCValue Value;
+ if (!Expr->evaluateAsValue(Value, *this))
+ llvm_unreachable("Invalid Expression");
+
+ const MCSymbolRefExpr *RefB = Value.getSymB();
+ if (RefB)
+ Assembler.getContext().reportFatalError(
+ SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
+ "' could not be evaluated in a subtraction expression");
+
+ const MCSymbolRefExpr *A = Value.getSymA();
+ if (!A)
+ return nullptr;
+
+ const MCSymbol &ASym = A->getSymbol();
+ const MCAssembler &Asm = getAssembler();
+ if (ASym.isCommon()) {
+ // FIXME: we should probably add a SMLoc to MCExpr.
+ Asm.getContext().reportFatalError(SMLoc(),
+ "Common symbol " + ASym.getName() +
+ " cannot be used in assignment expr");
+ }
+
+ return &ASym;
+}
+
+uint64_t MCAsmLayout::getSectionAddressSize(const MCSection *Sec) const {
// The size is the last fragment's end offset.
- const MCFragment &F = SD->getFragmentList().back();
- return getFragmentOffset(&F) + getFragmentEffectiveSize(&F);
+ const MCFragment &F = Sec->getFragmentList().back();
+ return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
}
-uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
+uint64_t MCAsmLayout::getSectionFileSize(const MCSection *Sec) const {
// Virtual sections have no file size.
- if (getAssembler().getBackend().isVirtualSection(SD->getSection()))
+ if (Sec->isVirtualSection())
return 0;
// Otherwise, the file size is the same as the address space size.
- return getSectionAddressSize(SD);
+ return getSectionAddressSize(Sec);
}
-uint64_t MCAsmLayout::getSectionSize(const MCSectionData *SD) const {
- // The logical size is the address space size minus any tail padding.
- uint64_t Size = getSectionAddressSize(SD);
- const MCAlignFragment *AF =
- dyn_cast<MCAlignFragment>(&(SD->getFragmentList().back()));
- if (AF && AF->hasOnlyAlignAddress())
- Size -= getFragmentEffectiveSize(AF);
-
- return Size;
+uint64_t llvm::computeBundlePadding(const MCAssembler &Assembler,
+ 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(FragmentType _Kind, MCSectionData *_Parent)
- : Kind(_Kind), Parent(_Parent), Atom(0), EffectiveSize(~UINT64_C(0))
-{
- if (Parent)
- Parent->getFragmentList().push_back(this);
+MCFragment::~MCFragment() {
}
-MCFragment::~MCFragment() {
+MCFragment::MCFragment(FragmentType Kind, MCSection *Parent)
+ : Kind(Kind), Parent(Parent), Atom(nullptr), Offset(~UINT64_C(0)) {
+ if (Parent)
+ Parent->getFragmentList().push_back(this);
}
/* *** */
-MCSectionData::MCSectionData() : Section(0) {}
-
-MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
- : Section(&_Section),
- Alignment(1),
- Address(~UINT64_C(0)),
- HasInstructions(false)
-{
- if (A)
- A->getSectionList().push_back(this);
+MCEncodedFragment::~MCEncodedFragment() {
}
/* *** */
-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), CommonAlign(0), Flags(0), Index(0)
-{
- if (A)
- A->getSymbolList().push_back(this);
+MCEncodedFragmentWithFixups::~MCEncodedFragmentWithFixups() {
}
/* *** */
-MCAssembler::MCAssembler(MCContext &_Context, TargetAsmBackend &_Backend,
- MCCodeEmitter &_Emitter, raw_ostream &_OS)
- : Context(_Context), Backend(_Backend), Emitter(_Emitter),
- OS(_OS), RelaxAll(false), 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),
+ SubsectionsViaSymbols(false), ELFHeaderEFlags(0) {
+ VersionMinInfo.Major = 0; // Major version == 0 for "none specified"
}
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 considering 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();
+ IndirectSymbols.clear();
+ DataRegions.clear();
+ LinkerOptions.clear();
+ FileNames.clear();
+ ThumbFuncs.clear();
+ BundleAlignSize = 0;
+ RelaxAll = false;
+ SubsectionsViaSymbols = false;
+ ELFHeaderEFlags = 0;
+ LOHContainer.reset();
+ VersionMinInfo.Major = 0;
+
+ // reset objects owned by us
+ getBackend().reset();
+ getEmitter().reset();
+ getWriter().reset();
+ getLOHContainer().reset();
}
-static bool isScatteredFixupFullyResolved(const MCAssembler &Asm,
- const MCAsmLayout &Layout,
- 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.
+bool MCAssembler::isThumbFunc(const MCSymbol *Symbol) const {
+ if (ThumbFuncs.count(Symbol))
+ return true;
- 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;
+ if (!Symbol->isVariable())
+ return false;
- A_Base = Asm.getAtom(Layout, &Asm.getSymbolData(A->getSymbol()));
- if (!A_Base)
- return false;
- }
+ // FIXME: It looks like gas supports some cases of the form "foo + 2". It
+ // is not clear if that is a bug or a feature.
+ const MCExpr *Expr = Symbol->getVariableValue();
+ const MCSymbolRefExpr *Ref = dyn_cast<MCSymbolRefExpr>(Expr);
+ if (!Ref)
+ return false;
- if (const MCSymbolRefExpr *B = Target.getSymB()) {
- // Modified symbol references cannot be resolved.
- if (B->getKind() != MCSymbolRefExpr::VK_None)
- return false;
+ if (Ref->getKind() != MCSymbolRefExpr::VK_None)
+ return false;
- B_Base = Asm.getAtom(Layout, &Asm.getSymbolData(B->getSymbol()));
- if (!B_Base)
- return false;
- }
+ const MCSymbol &Sym = Ref->getSymbol();
+ if (!isThumbFunc(&Sym))
+ return false;
+
+ ThumbFuncs.insert(Symbol); // Cache it.
+ return true;
+}
- // 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;
+void MCAssembler::addLocalUsedInReloc(const MCSymbol &Sym) {
+ assert(Sym.isTemporary());
+ LocalsUsedInReloc.insert(&Sym);
+}
- // Otherwise, B must be missing and A must be the base.
- return !B_Base && BaseSymbol == A_Base;
+bool MCAssembler::isLocalUsedInReloc(const MCSymbol &Sym) const {
+ assert(Sym.isTemporary());
+ return LocalsUsedInReloc.count(&Sym);
}
-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());
+ if (isLocalUsedInReloc(Symbol))
+ return true;
+
+ return false;
}
-const MCSymbolData *MCAssembler::getAtom(const MCAsmLayout &Layout,
- const MCSymbolData *SD) const {
+const MCSymbol *MCAssembler::getAtom(const MCSymbol &S) const {
// Linker visible symbols define atoms.
- if (isSymbolLinkerVisible(SD))
- return SD;
+ if (isSymbolLinkerVisible(S))
+ return &S;
// Absolute and undefined symbols have no defining atom.
- if (!SD->getFragment())
- return 0;
+ if (!S.getFragment())
+ return nullptr;
// Non-linker visible symbols in sections which can't be atomized have no
// defining atom.
- if (!getBackend().isSectionAtomizable(
- SD->getFragment()->getParent()->getSection()))
- return 0;
+ if (!getContext().getAsmInfo()->isSectionAtomizableBySymbols(
+ *S.getFragment()->getParent()))
+ return nullptr;
// Otherwise, return the atom for the containing fragment.
- return SD->getFragment()->getAtom();
+ return S.getFragment()->getAtom();
}
-bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout,
- const MCAsmFixup &Fixup, const MCFragment *DF,
+bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
+ const MCFixup &Fixup, const MCFragment *DF,
MCValue &Target, uint64_t &Value) const {
- ++stats::EvaluateFixup;
+ ++stats::evaluateFixup;
- if (!Fixup.Value->EvaluateAsRelocatable(Target, &Layout))
- report_fatal_error("expected relocatable expression");
+ // FIXME: This code has some duplication with RecordRelocation. We should
+ // probably merge the two into a single callback that tries to evaluate a
+ // fixup and records a relocation if one is needed.
+ const MCExpr *Expr = Fixup.getValue();
+ if (!Expr->EvaluateAsRelocatable(Target, &Layout, &Fixup))
+ getContext().reportFatalError(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.isUndefined()) {
+ IsResolved = false;
+ } else {
+ IsResolved = getWriter().IsSymbolRefDifferenceFullyResolvedImpl(
+ *this, SA, *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 += Layout.getSymbolAddress(&getSymbolData(A->getSymbol()));
- else
- IsResolved = false;
+ const MCSymbol &Sym = A->getSymbol();
+ if (Sym.isDefined())
+ Value += Layout.getSymbolOffset(Sym);
}
if (const MCSymbolRefExpr *B = Target.getSymB()) {
- if (B->getSymbol().isDefined())
- Value -= Layout.getSymbolAddress(&getSymbolData(B->getSymbol()));
- else
- IsResolved = false;
+ const MCSymbol &Sym = B->getSymbol();
+ if (Sym.isDefined())
+ Value -= Layout.getSymbolOffset(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 = DF->getAtom();
- if (!BaseSymbol)
- IsResolved = false;
- }
- if (IsResolved)
- IsResolved = isScatteredFixupFullyResolved(*this, Layout, 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 -= Layout.getFragmentAddress(DF) + 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;
}
-uint64_t MCAssembler::ComputeFragmentSize(MCAsmLayout &Layout,
- const MCFragment &F,
- uint64_t SectionAddress,
- uint64_t FragmentOffset) const {
+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_Relaxable:
+ case MCFragment::FT_CompactEncodedInst:
+ return cast<MCEncodedFragment>(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);
-
- assert((!AF.hasOnlyAlignAddress() || !AF.getNextNode()) &&
- "Invalid OnlyAlignAddress bit, not the last fragment!");
-
- uint64_t Size = OffsetToAlignment(SectionAddress + FragmentOffset,
- AF.getAlignment());
-
- // Honor MaxBytesToEmit.
+ 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: {
const MCOrgFragment &OF = cast<MCOrgFragment>(F);
-
- // FIXME: We should compute this sooner, we don't want to recurse here, and
- // we would like to be more functional.
int64_t TargetLocation;
- if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, &Layout))
+ if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
report_fatal_error("expected assembly-time absolute expression");
// FIXME: We need a way to communicate this error.
- int64_t Offset = TargetLocation - FragmentOffset;
- if (Offset < 0)
+ 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 Offset;
- }
+ "' (at offset '" + Twine(FragmentOffset) + "')");
+ return Size;
}
- assert(0 && "invalid fragment kind");
- return 0;
-}
-
-void MCAsmLayout::LayoutFile() {
- // Initialize the first section.
- if (!getSectionOrder().empty())
- getSectionOrder().front()->Address = 0;
-
- for (unsigned i = 0, e = getSectionOrder().size(); i != e; ++i) {
- MCSectionData *SD = getSectionOrder()[i];
-
- for (MCSectionData::iterator it = SD->begin(),
- ie = SD->end(); it != ie; ++it)
- LayoutFragment(it);
+ 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) {
- uint64_t StartAddress = getSectionAddress(F->getParent());
+void MCAsmLayout::layoutFragment(MCFragment *F) {
+ MCFragment *Prev = F->getPrevNode();
- // Get the fragment start address.
- uint64_t Address = StartAddress;
- MCSectionData::iterator it = F;
- if (MCFragment *Prev = F->getPrevNode())
- Address = (StartAddress + getFragmentOffset(Prev) +
- getFragmentEffectiveSize(Prev));
+ // 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!");
++stats::FragmentLayouts;
// Compute fragment offset and size.
- F->Offset = Address - StartAddress;
- F->EffectiveSize = getAssembler().ComputeFragmentSize(*this, *F, StartAddress,
- F->Offset);
-
- // If this is the last fragment in a section, update the next section address.
- if (!F->getNextNode()) {
- unsigned NextIndex = F->getParent()->getLayoutOrder() + 1;
- if (NextIndex != getSectionOrder().size())
- LayoutSection(getSectionOrder()[NextIndex]);
+ if (Prev)
+ F->Offset = Prev->Offset + getAssembler().computeFragmentSize(*this, *Prev);
+ else
+ F->Offset = 0;
+ LastValidFragment[F->getParent()] = F;
+
+ // 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.
+ //
+ // When the -mc-relax-all flag is used, we optimize bundling by writting the
+ // bundle padding directly into fragments when the instructions are emitted
+ // inside the streamer.
+ //
+ if (Assembler.isBundlingEnabled() && !Assembler.getRelaxAll() &&
+ 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(Assembler, 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;
}
}
-void MCAsmLayout::LayoutSection(MCSectionData *SD) {
- unsigned SectionOrderIndex = SD->getLayoutOrder();
-
- ++stats::SectionLayouts;
+/// \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());
+}
- // Compute the section start address.
- uint64_t StartAddress = 0;
- if (SectionOrderIndex) {
- MCSectionData *Prev = getSectionOrder()[SectionOrderIndex - 1];
- StartAddress = getSectionAddress(Prev) + getSectionAddressSize(Prev);
+void MCAssembler::writeFragmentPadding(const MCFragment &F, uint64_t FSize,
+ MCObjectWriter *OW) const {
+ // Should NOP padding be written out before this fragment?
+ unsigned BundlePadding = F.getBundlePadding();
+ if (BundlePadding > 0) {
+ assert(isBundlingEnabled() &&
+ "Writing bundle padding with disabled bundling");
+ assert(F.hasInstructions() &&
+ "Writing bundle padding for a fragment without instructions");
+
+ unsigned TotalLength = BundlePadding + static_cast<unsigned>(FSize);
+ if (F.alignToBundleEnd() && TotalLength > 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 - getBundleAlignSize();
+ if (!getBackend().writeNopData(DistanceToBoundary, OW))
+ report_fatal_error("unable to write NOP sequence of " +
+ Twine(DistanceToBoundary) + " bytes");
+ BundlePadding -= DistanceToBoundary;
+ }
+ if (!getBackend().writeNopData(BundlePadding, OW))
+ report_fatal_error("unable to write NOP sequence of " +
+ Twine(BundlePadding) + " bytes");
}
+}
- // Honor the section alignment requirements.
- StartAddress = RoundUpToAlignment(StartAddress, SD->getAlignment());
+/// \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();
- // Set the section address.
- SD->Address = StartAddress;
-}
+ // FIXME: Embed in fragments instead?
+ uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
+
+ Asm.writeFragmentPadding(F, FragmentSize, OW);
-/// WriteFragmentData - Write the \arg F data to the output file.
-static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
- 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;
++stats::EmittedFragments;
- // FIXME: Embed in fragments instead?
- uint64_t FragmentSize = Layout.getFragmentEffectiveSize(&F);
switch (F.getKind()) {
case MCFragment::FT_Align: {
- MCAlignFragment &AF = cast<MCAlignFragment>(F);
- uint64_t Count = FragmentSize / 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?
// 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.
+ // 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))
+ 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: {
- MCDataFragment &DF = cast<MCDataFragment>(F);
- assert(FragmentSize == DF.getContents().size() && "Invalid size!");
- OW->WriteBytes(DF.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);
+ ++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_Inst:
- llvm_unreachable("unexpected inst fragment after lowering");
+ case MCFragment::FT_LEB: {
+ const MCLEBFragment &LF = cast<MCLEBFragment>(F);
+ OW->WriteBytes(LF.getContents());
break;
+ }
case MCFragment::FT_Org: {
- MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ ++stats::EmittedOrgFragments;
+ const 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());
+ break;
+ }
+ case MCFragment::FT_DwarfFrame: {
+ const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
+ OW->WriteBytes(CF.getContents());
+ break;
+ }
}
- assert(OW->getStream().tell() - Start == FragmentSize);
+ assert(OW->getStream().tell() - Start == FragmentSize &&
+ "The stream should advance by fragment size");
}
-void MCAssembler::WriteSectionData(const MCSectionData *SD,
- const MCAsmLayout &Layout,
- MCObjectWriter *OW) const {
+void MCAssembler::writeSectionData(const MCSection *Sec,
+ const MCAsmLayout &Layout) const {
// Ignore virtual sections.
- if (getBackend().isVirtualSection(SD->getSection())) {
- assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
+ if (Sec->isVirtualSection()) {
+ assert(Layout.getSectionFileSize(Sec) == 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) {
+ for (MCSection::const_iterator it = Sec->begin(), ie = Sec->end(); it != ie;
+ ++it) {
switch (it->getKind()) {
- default:
- assert(0 && "Invalid fragment in virtual section!");
+ 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)
+ if (DF.getContents()[i]) {
+ if (auto *ELFSec = dyn_cast<const MCSectionELF>(Sec))
+ report_fatal_error("non-zero initializer found in section '" +
+ ELFSec->getSectionName() + "'");
+ else
+ report_fatal_error("non-zero initializer found in virtual section");
+ }
+ break;
+ }
case MCFragment::FT_Align:
- assert(!cast<MCAlignFragment>(it)->getValueSize() &&
+ // 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() &&
+ 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)
- WriteFragmentData(*this, Layout, *it, OW);
+ for (MCSection::const_iterator it = Sec->begin(), ie = Sec->end(); it != ie;
+ ++it)
+ writeFragment(*this, Layout, *it);
- assert(OW->getStream().tell() - Start == Layout.getSectionFileSize(SD));
+ assert(getWriter().getStream().tell() - Start ==
+ Layout.getSectionAddressSize(Sec));
+}
+
+std::pair<uint64_t, bool> MCAssembler::handleFixup(const MCAsmLayout &Layout,
+ MCFragment &F,
+ const MCFixup &Fixup) {
+ // Evaluate the fixup.
+ MCValue Target;
+ uint64_t FixedValue;
+ bool IsPCRel = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
+ MCFixupKindInfo::FKF_IsPCRel;
+ 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, IsPCRel,
+ FixedValue);
+ }
+ return std::make_pair(FixedValue, IsPCRel);
}
void MCAssembler::Finish() {
// Create the layout object.
MCAsmLayout Layout(*this);
- // Insert additional align fragments for concrete sections to explicitly pad
- // the previous section to match their alignment requirements. This is for
- // 'gas' compatibility, it shouldn't strictly be necessary.
- //
- // FIXME: This may be Mach-O specific.
- for (unsigned i = 1, e = Layout.getSectionOrder().size(); i < e; ++i) {
- MCSectionData *SD = Layout.getSectionOrder()[i];
-
- // Ignore sections without alignment requirements.
- unsigned Align = SD->getAlignment();
- if (Align <= 1)
- continue;
-
- // Ignore virtual sections, they don't cause file size modifications.
- if (getBackend().isVirtualSection(SD->getSection()))
- continue;
-
- // Otherwise, create a new align fragment at the end of the previous
- // section.
- MCAlignFragment *AF = new MCAlignFragment(Align, 0, 1, Align,
- Layout.getSectionOrder()[i - 1]);
- AF->setOnlyAlignAddress(true);
- }
-
// 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()) {
- unsigned ValueSize = 1;
- if (getBackend().isVirtualSection(it->getSection()))
- ValueSize = 1;
- new MCFillFragment(0, 1, 0, it);
- }
+ if (it->getFragmentList().empty())
+ new MCDataFragment(&*it);
it->setOrdinal(SectionIndex++);
}
// Assign layout order indices to sections and fragments.
- unsigned FragmentIndex = 0;
for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
- MCSectionData *SD = Layout.getSectionOrder()[i];
- SD->setLayoutOrder(i);
+ MCSection *Sec = Layout.getSectionOrder()[i];
+ Sec->setLayoutOrder(i);
- for (MCSectionData::iterator it2 = SD->begin(),
- ie2 = SD->end(); it2 != ie2; ++it2)
- it2->setLayoutOrder(FragmentIndex++);
+ unsigned FragmentIndex = 0;
+ for (MCSection::iterator iFrag = Sec->begin(), iFragEnd = Sec->end();
+ iFrag != iFragEnd; ++iFrag)
+ iFrag->setLayoutOrder(FragmentIndex++);
}
// Layout until everything fits.
- while (LayoutOnce(Layout))
+ while (layoutOnce(Layout))
continue;
DEBUG_WITH_TYPE("mc-dump", {
dump(); });
// Finalize the layout, including fragment lowering.
- FinishLayout(Layout);
+ finishLayout(Layout);
DEBUG_WITH_TYPE("mc-dump", {
llvm::errs() << "assembler backend - final-layout\n--\n";
dump(); });
uint64_t StartOffset = OS.tell();
- llvm::OwningPtr<MCObjectWriter> Writer(getBackend().createObjectWriter(OS));
- if (!Writer)
- report_fatal_error("unable to create object writer!");
// 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, Layout, DF, Fixup, Target,FixedValue);
+ for (MCSection::iterator it2 = it->begin(), ie2 = it->end(); it2 != ie2;
+ ++it2) {
+ 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;
+ bool IsPCRel;
+ std::tie(FixedValue, IsPCRel) = handleFixup(Layout, *F, Fixup);
+ getBackend().applyFixup(Fixup, F->getContents().data(),
+ F->getContents().size(), FixedValue, IsPCRel);
}
-
- getBackend().ApplyFixup(Fixup, *DF, FixedValue);
}
}
}
// Write the object file.
- Writer->WriteObject(*this, Layout);
- OS.flush();
+ getWriter().WriteObject(*this, Layout);
stats::ObjectBytes += OS.tell() - StartOffset;
}
-bool MCAssembler::FixupNeedsRelaxation(const MCAsmFixup &Fixup,
- const MCFragment *DF,
+bool MCAssembler::fixupNeedsRelaxation(const MCFixup &Fixup,
+ const MCRelaxableFragment *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))
+ if (!evaluateFixup(Layout, Fixup, DF, Target, Value))
return true;
- // Otherwise, relax if the value is too big for a (signed) i8.
- //
- // FIXME: This is target dependent!
- return int64_t(Value) != int64_t(int8_t(Value));
+ return getBackend().fixupNeedsRelaxation(Fixup, Value, DF, Layout);
}
-bool MCAssembler::FragmentNeedsRelaxation(const MCInstFragment *IF,
+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(IF->getInst(), IF->getFixups()))
+ if (!getBackend().mayNeedRelaxation(F->getInst()))
return false;
- for (MCInstFragment::const_fixup_iterator it = IF->fixup_begin(),
- ie = IF->fixup_end(); it != ie; ++it)
- if (FixupNeedsRelaxation(*it, IF, Layout))
+ for (MCRelaxableFragment::const_fixup_iterator it = F->fixup_begin(),
+ ie = F->fixup_end(); it != ie; ++it)
+ if (fixupNeedsRelaxation(*it, F, Layout))
return true;
return false;
}
-bool MCAssembler::LayoutOnce(MCAsmLayout &Layout) {
- ++stats::RelaxationSteps;
+bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
+ MCRelaxableFragment &F) {
+ if (!fragmentNeedsRelaxation(&F, Layout))
+ return false;
- // Layout the sections in order.
- Layout.LayoutFile();
+ ++stats::RelaxedInstructions;
- // Scan for fragments that need relaxation.
- bool WasRelaxed = false;
- for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
-
- for (MCSectionData::iterator it2 = SD.begin(),
- ie2 = SD.end(); it2 != ie2; ++it2) {
- // Check if this is an instruction fragment that needs relaxation.
- MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
- if (!IF || !FragmentNeedsRelaxation(IF, Layout))
- continue;
-
- ++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, 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.
- int SlideAmount = Code.size() - IF->getInstSize();
- IF->setInst(Relaxed);
- IF->getCode() = Code;
- IF->getFixups().clear();
- for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
- MCFixup &F = Fixups[i];
- IF->getFixups().push_back(MCAsmFixup(F.getOffset(), *F.getValue(),
- F.getKind()));
- }
+ // FIXME-PERF: We could immediately lower out instructions if we can tell
+ // they are fully resolved, to avoid retesting on later passes.
- // Update the layout, and remember that we relaxed. If we are relaxing
- // everything, we can skip this step since nothing will depend on updating
- // the values.
- if (!getRelaxAll())
- Layout.UpdateForSlide(IF, SlideAmount);
- WasRelaxed = true;
- }
- }
+ // Relax the fragment.
- return WasRelaxed;
-}
+ MCInst Relaxed;
+ getBackend().relaxInstruction(F.getInst(), Relaxed);
-void MCAssembler::FinishLayout(MCAsmLayout &Layout) {
- // Lower out any instruction fragments, to simplify the fixup application and
- // output.
+ // Encode the new instruction.
//
- // FIXME-PERF: We don't have to do this, but the assumption is that it is
- // cheap (we will mostly end up eliminating fragments and appending on to data
- // fragments), so the extra complexity downstream isn't worth it. Evaluate
- // this assumption.
- for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
-
- for (MCSectionData::iterator it2 = SD.begin(),
- ie2 = SD.end(); it2 != ie2; ++it2) {
- MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
- if (!IF)
- continue;
-
- // Create a new data fragment for the instruction.
- //
- // FIXME-PERF: Reuse previous data fragment if possible.
- MCDataFragment *DF = new MCDataFragment();
- SD.getFragmentList().insert(it2, DF);
-
- // Update the data fragments layout data.
- DF->setParent(IF->getParent());
- DF->setAtom(IF->getAtom());
- DF->setLayoutOrder(IF->getLayoutOrder());
- Layout.FragmentReplaced(IF, DF);
-
- // Copy in the data and the fixups.
- DF->getContents().append(IF->getCode().begin(), IF->getCode().end());
- for (unsigned i = 0, e = IF->getFixups().size(); i != e; ++i)
- DF->getFixups().push_back(IF->getFixups()[i]);
-
- // Delete the instruction fragment and update the iterator.
- SD.getFragmentList().erase(IF);
- it2 = DF;
- }
- }
-}
-
-// Debugging methods
+ // 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, F.getSubtargetInfo());
+ VecOS.flush();
+
+ // Update the fragment.
+ F.setInst(Relaxed);
+ F.getContents() = Code;
+ F.getFixups() = Fixups;
-namespace llvm {
-
-raw_ostream &operator<<(raw_ostream &OS, const MCAsmFixup &AF) {
- OS << "<MCAsmFixup" << " Offset:" << AF.Offset << " Value:" << *AF.Value
- << " Kind:" << AF.Kind << ">";
- return OS;
+ return true;
}
+bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
+ uint64_t OldSize = LF.getContents().size();
+ int64_t Value;
+ bool Abs = LF.getValue().evaluateKnownAbsolute(Value, Layout);
+ if (!Abs)
+ report_fatal_error("sleb128 and uleb128 expressions must be absolute");
+ 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();
}
-void MCFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
- << " Offset:" << Offset << " EffectiveSize:" << EffectiveSize << ">";
+bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
+ MCDwarfLineAddrFragment &DF) {
+ MCContext &Context = Layout.getAssembler().getContext();
+ uint64_t OldSize = DF.getContents().size();
+ int64_t AddrDelta;
+ bool Abs = DF.getAddrDelta().evaluateKnownAbsolute(AddrDelta, Layout);
+ assert(Abs && "We created a line delta with an invalid expression");
+ (void) Abs;
+ 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();
}
-void MCAlignFragment::dump() {
- raw_ostream &OS = llvm::errs();
+bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
+ MCDwarfCallFrameFragment &DF) {
+ MCContext &Context = Layout.getAssembler().getContext();
+ uint64_t OldSize = DF.getContents().size();
+ int64_t AddrDelta;
+ bool Abs = DF.getAddrDelta().evaluateKnownAbsolute(AddrDelta, Layout);
+ assert(Abs && "We created call frame with an invalid expression");
+ (void) Abs;
+ SmallString<8> &Data = DF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
- OS << "<MCAlignFragment ";
- this->MCFragment::dump();
- if (hasEmitNops())
- OS << " (emit nops)";
- if (hasOnlyAlignAddress())
- OS << " (only align section)";
- OS << "\n ";
- OS << " Alignment:" << getAlignment()
- << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " MaxBytesToEmit:" << getMaxBytesToEmit() << ">";
+bool MCAssembler::layoutSectionOnce(MCAsmLayout &Layout, MCSection &Sec) {
+ // 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 = nullptr;
+
+ // Attempt to relax all the fragments in the section.
+ for (MCSection::iterator I = Sec.begin(), IE = Sec.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;
}
-void MCDataFragment::dump() {
- raw_ostream &OS = llvm::errs();
+bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
+ ++stats::RelaxationSteps;
- 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;
- }
- OS << "]";
+ bool WasRelaxed = false;
+ for (iterator it = begin(), ie = end(); it != ie; ++it) {
+ MCSection &Sec = *it;
+ while (layoutSectionOnce(Layout, Sec))
+ WasRelaxed = true;
}
- OS << ">";
+ return WasRelaxed;
}
-void MCFillFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCFillFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " Size:" << getSize() << ">";
+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());
+ }
}
-void MCInstFragment::dump() {
- raw_ostream &OS = llvm::errs();
+// Debugging methods
- OS << "<MCInstFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Inst:";
- getInst().dump_pretty(OS);
- OS << ">";
-}
+namespace llvm {
-void MCOrgFragment::dump() {
- raw_ostream &OS = llvm::errs();
+raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
+ OS << "<MCFixup" << " Offset:" << AF.getOffset()
+ << " Value:" << *AF.getValue()
+ << " Kind:" << AF.getKind() << ">";
+ return OS;
+}
- OS << "<MCOrgFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Offset:" << getOffset() << " Value:" << getValue() << ">";
}
-void MCSectionData::dump() {
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void MCFragment::dump() {
raw_ostream &OS = llvm::errs();
- OS << "<MCSectionData";
- OS << " Alignment:" << getAlignment() << " Address:" << Address
- << " Fragments:[\n ";
- for (iterator it = begin(), ie = end(); it != ie; ++it) {
- if (it != begin()) OS << ",\n ";
- it->dump();
+ 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;
}
- OS << "]>";
-}
-void MCSymbolData::dump() {
- raw_ostream &OS = llvm::errs();
+ OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
+ << " Offset:" << Offset
+ << " HasInstructions:" << hasInstructions()
+ << " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
- 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)";
+ 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->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 << ">";
}
for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
if (it != symbol_begin()) OS << ",\n ";
+ OS << "(";
it->dump();
+ OS << ", Index:" << it->getIndex() << ", ";
+ OS << ")";
}
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