#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
+#include "llvm/MC/MCDwarf.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
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->getSection().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->getSection().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.
- for (unsigned i = 0, e = getSectionOrder().size(); i != e; ++i)
- getAssembler().LayoutSection(*this, i);
+bool MCAsmLayout::isFragmentUpToDate(const MCFragment *F) const {
+ const MCSectionData &SD = *F->getParent();
+ const MCFragment *LastValid = LastValidFragment.lookup(&SD);
+ if (!LastValid)
+ return false;
+ assert(LastValid->getParent() == F->getParent());
+ return F->getLayoutOrder() <= LastValid->getLayoutOrder();
}
-void MCAsmLayout::FragmentReplaced(MCFragment *Src, MCFragment *Dst) {
- Dst->Offset = Src->Offset;
- Dst->EffectiveSize = Src->EffectiveSize;
-}
+void MCAsmLayout::Invalidate(MCFragment *F) {
+ // If this fragment wasn't already up-to-date, we don't need to do anything.
+ if (!isFragmentUpToDate(F))
+ return;
-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 this fragment.
+ const MCSectionData &SD = *F->getParent();
+ LastValidFragment[&SD] = F;
}
-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 {
+ MCSectionData &SD = *F->getParent();
+
+ MCFragment *Cur = LastValidFragment[&SD];
+ if (!Cur)
+ Cur = &*SD.begin();
+ else
+ Cur = Cur->getNextNode();
-void MCAsmLayout::setFragmentEffectiveSize(MCFragment *F, uint64_t Value) {
- F->EffectiveSize = Value;
+ // Advance the layout position until the fragment is up-to-date.
+ while (!isFragmentUpToDate(F)) {
+ const_cast<MCAsmLayout*>(this)->LayoutFragment(Cur);
+ Cur = Cur->getNextNode();
+ }
}
uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
+ EnsureValid(F);
assert(F->Offset != ~UINT64_C(0) && "Address not set!");
return F->Offset;
}
-void MCAsmLayout::setFragmentOffset(MCFragment *F, uint64_t Value) {
- F->Offset = Value;
-}
-
-uint64_t MCAsmLayout::getSymbolAddress(const MCSymbolData *SD) const {
- assert(SD->getFragment() && "Invalid getAddress() on undefined symbol!");
- return getFragmentAddress(SD->getFragment()) + SD->getOffset();
-}
-
-uint64_t MCAsmLayout::getSectionAddress(const MCSectionData *SD) const {
- assert(SD->Address != ~UINT64_C(0) && "Address not set!");
- return SD->Address;
-}
-
-void MCAsmLayout::setSectionAddress(MCSectionData *SD, uint64_t Value) {
- SD->Address = Value;
+uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
+ assert(SD->getFragment() && "Invalid getOffset() on undefined symbol!");
+ return getFragmentOffset(SD->getFragment()) + SD->getOffset();
}
uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
- // Empty sections have no size.
- if (SD->getFragmentList().empty())
- return 0;
-
- // Otherwise, the size is the last fragment's end offset.
+ // The size is the last fragment's end offset.
const MCFragment &F = SD->getFragmentList().back();
- return getFragmentOffset(&F) + getFragmentEffectiveSize(&F);
+ return getFragmentOffset(&F) + getAssembler().ComputeFragmentSize(F);
}
uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
// Virtual sections have no file size.
- if (getAssembler().getBackend().isVirtualSection(SD->getSection()))
+ if (SD->getSection().isVirtualSection())
return 0;
// Otherwise, the file size is the same as the address space size.
return getSectionAddressSize(SD);
}
-uint64_t MCAsmLayout::getSectionSize(const MCSectionData *SD) const {
- // Empty sections have no size.
- if (SD->getFragmentList().empty())
- return 0;
-
- // 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;
-}
-
/* *** */
MCFragment::MCFragment() : Kind(FragmentType(~0)) {
}
+MCFragment::~MCFragment() {
+}
+
MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
- : Kind(_Kind), Parent(_Parent), Atom(0), EffectiveSize(~UINT64_C(0))
+ : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
{
if (Parent)
Parent->getFragmentList().push_back(this);
}
-MCFragment::~MCFragment() {
-}
-
/* *** */
MCSectionData::MCSectionData() : Section(0) {}
MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
: Section(&_Section),
+ Ordinal(~UINT32_C(0)),
Alignment(1),
- Address(~UINT64_C(0)),
HasInstructions(false)
{
if (A)
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() {
}
-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;
-}
-
-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.
-
- 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(Layout, &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(Layout, &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());
+ return getBackend().doesSectionRequireSymbols(Symbol.getSection());
}
-const MCSymbolData *MCAssembler::getAtom(const MCAsmLayout &Layout,
- const MCSymbolData *SD) const {
+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.
return SD->getFragment()->getAtom();
}
-bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout,
- const MCAsmFixup &Fixup, const MCFragment *DF,
+bool MCAssembler::EvaluateFixup(const MCObjectWriter &Writer,
+ const MCAsmLayout &Layout,
+ const MCFixup &Fixup, const MCFragment *DF,
MCValue &Target, uint64_t &Value) const {
++stats::EvaluateFixup;
- if (!Fixup.Value->EvaluateAsRelocatable(Target, &Layout))
+ if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
report_fatal_error("expected relocatable expression");
// FIXME: How do non-scattered symbols work in ELF? I presume the linker
Value = Target.getConstant();
- bool IsPCRel =
- Emitter.getFixupKindInfo(Fixup.Kind).Flags & MCFixupKindInfo::FKF_IsPCRel;
+ bool IsPCRel = Backend.getFixupKindInfo(
+ Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
bool IsResolved = true;
+ bool IsThumb = false;
if (const MCSymbolRefExpr *A = Target.getSymA()) {
- if (A->getSymbol().isDefined())
- Value += Layout.getSymbolAddress(&getSymbolData(A->getSymbol()));
+ const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value += Layout.getSymbolOffset(&getSymbolData(Sym));
else
IsResolved = false;
+ if (isThumbFunc(&Sym))
+ IsThumb = true;
}
if (const MCSymbolRefExpr *B = Target.getSymB()) {
- if (B->getSymbol().isDefined())
- Value -= Layout.getSymbolAddress(&getSymbolData(B->getSymbol()));
+ const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
else
IsResolved = false;
}
- // 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();
-
- IsResolved = isScatteredFixupFullyResolvedSimple(*this, Fixup, Target,
- BaseSection);
- }
+ if (IsResolved)
+ IsResolved = Writer.IsFixupFullyResolved(*this, Target, IsPCRel, DF);
+
+ bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
+ MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
+ assert((ShouldAlignPC ? IsPCRel : true) &&
+ "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
+
+ if (IsPCRel) {
+ uint32_t Offset = 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 -= Layout.getFragmentOffset(DF) + Offset;
}
- if (IsPCRel)
- Value -= Layout.getFragmentAddress(DF) + Fixup.Offset;
+ // ARM fixups based from a thumb function address need to have the low
+ // bit set. The actual value is always at least 16-bit aligned, so the
+ // low bit is normally clear and available for use as an ISA flag for
+ // interworking.
+ if (IsThumb)
+ Value |= 1;
return IsResolved;
}
-void MCAssembler::LayoutFragment(MCAsmLayout &Layout, MCFragment &F) {
- uint64_t StartAddress = Layout.getSectionAddress(F.getParent());
-
- // Get the fragment start address.
- uint64_t Address = StartAddress;
- MCSectionData::iterator it = &F;
- if (MCFragment *Prev = F.getPrevNode())
- Address = (StartAddress + Layout.getFragmentOffset(Prev) +
- Layout.getFragmentEffectiveSize(Prev));
-
- ++stats::FragmentLayouts;
-
- uint64_t FragmentOffset = Address - StartAddress;
- Layout.setFragmentOffset(&F, FragmentOffset);
-
- // Evaluate fragment size.
- uint64_t EffectiveSize = 0;
+uint64_t MCAssembler::ComputeFragmentSize(const MCFragment &F) const {
switch (F.getKind()) {
- case MCFragment::FT_Align: {
- MCAlignFragment &AF = cast<MCAlignFragment>(F);
-
- assert((!AF.hasOnlyAlignAddress() || !AF.getNextNode()) &&
- "Invalid OnlyAlignAddress bit, not the last fragment!");
-
- EffectiveSize = OffsetToAlignment(Address, AF.getAlignment());
- if (EffectiveSize > AF.getMaxBytesToEmit())
- EffectiveSize = 0;
- break;
- }
-
case MCFragment::FT_Data:
- EffectiveSize = cast<MCDataFragment>(F).getContents().size();
- break;
-
- case MCFragment::FT_Fill: {
- EffectiveSize = cast<MCFillFragment>(F).getSize();
- break;
- }
-
+ return cast<MCDataFragment>(F).getContents().size();
+ case MCFragment::FT_Fill:
+ return cast<MCFillFragment>(F).getSize();
case MCFragment::FT_Inst:
- EffectiveSize = cast<MCInstFragment>(F).getInstSize();
- break;
+ return cast<MCInstFragment>(F).getInstSize();
- case MCFragment::FT_Org: {
- MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ case MCFragment::FT_LEB:
+ return cast<MCLEBFragment>(F).getContents().size();
- int64_t TargetLocation;
- if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, &Layout))
- report_fatal_error("expected assembly-time absolute expression");
+ case MCFragment::FT_Align:
+ return cast<MCAlignFragment>(F).getSize();
- // FIXME: We need a way to communicate this error.
- int64_t Offset = TargetLocation - FragmentOffset;
- if (Offset < 0)
- report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
- "' (at offset '" + Twine(FragmentOffset) + "'");
+ case MCFragment::FT_Org:
+ return cast<MCOrgFragment>(F).getSize();
- EffectiveSize = Offset;
- break;
- }
+ case MCFragment::FT_Dwarf:
+ return cast<MCDwarfLineAddrFragment>(F).getContents().size();
}
- Layout.setFragmentEffectiveSize(&F, EffectiveSize);
+ assert(0 && "invalid fragment kind");
+ return 0;
}
-void MCAssembler::LayoutSection(MCAsmLayout &Layout,
- unsigned SectionOrderIndex) {
- MCSectionData &SD = *Layout.getSectionOrder()[SectionOrderIndex];
+void MCAsmLayout::LayoutFragment(MCFragment *F) {
+ MCFragment *Prev = F->getPrevNode();
- ++stats::SectionLayouts;
+ // We should never try to recompute something which is up-to-date.
+ assert(!isFragmentUpToDate(F) && "Attempt to recompute up-to-date fragment!");
+ // We should never try to compute the fragment layout if it's predecessor
+ // isn't up-to-date.
+ assert((!Prev || isFragmentUpToDate(Prev)) &&
+ "Attempt to compute fragment before it's predecessor!");
- // Compute the section start address.
- uint64_t StartAddress = 0;
- if (SectionOrderIndex) {
- MCSectionData *Prev = Layout.getSectionOrder()[SectionOrderIndex - 1];
- StartAddress = (Layout.getSectionAddress(Prev) +
- Layout.getSectionAddressSize(Prev));
- }
-
- // Honor the section alignment requirements.
- StartAddress = RoundUpToAlignment(StartAddress, SD.getAlignment());
+ ++stats::FragmentLayouts;
- // Set the section address.
- Layout.setSectionAddress(&SD, StartAddress);
+ // Compute fragment offset and size.
+ uint64_t Offset = 0;
+ if (Prev)
+ Offset += Prev->Offset + getAssembler().ComputeFragmentSize(*Prev);
- for (MCSectionData::iterator it = SD.begin(), ie = SD.end(); it != ie; ++it)
- LayoutFragment(Layout, *it);
+ F->Offset = Offset;
+ LastValidFragment[F->getParent()] = F;
}
/// WriteFragmentData - Write the \arg F data to the output file.
++stats::EmittedFragments;
// FIXME: Embed in fragments instead?
- uint64_t FragmentSize = Layout.getFragmentEffectiveSize(&F);
+ uint64_t FragmentSize = Asm.ComputeFragmentSize(F);
switch (F.getKind()) {
case MCFragment::FT_Align: {
MCAlignFragment &AF = cast<MCAlignFragment>(F);
break;
}
- case MCFragment::FT_Inst:
- llvm_unreachable("unexpected inst fragment after lowering");
+ case MCFragment::FT_Inst: {
+ MCInstFragment &IF = cast<MCInstFragment>(F);
+ OW->WriteBytes(StringRef(IF.getCode().begin(), IF.getCode().size()));
break;
+ }
+
+ case MCFragment::FT_LEB: {
+ MCLEBFragment &LF = cast<MCLEBFragment>(F);
+ OW->WriteBytes(LF.getContents().str());
+ break;
+ }
case MCFragment::FT_Org: {
MCOrgFragment &OF = cast<MCOrgFragment>(F);
break;
}
+
+ case MCFragment::FT_Dwarf: {
+ const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
+ OW->WriteBytes(OF.getContents().str());
+ break;
+ }
}
assert(OW->getStream().tell() - Start == FragmentSize);
const MCAsmLayout &Layout,
MCObjectWriter *OW) const {
// Ignore virtual sections.
- if (getBackend().isVirtualSection(SD->getSection())) {
+ if (SD->getSection().isVirtualSection()) {
assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
// Check that contents are only things legal inside a virtual section.
switch (it->getKind()) {
default:
assert(0 && "Invalid fragment in virtual section!");
+ case MCFragment::FT_Data: {
+ // Check that we aren't trying to write a non-zero contents (or fixups)
+ // into a virtual section. This is to support clients which use standard
+ // directives to fill the contents of virtual sections.
+ MCDataFragment &DF = cast<MCDataFragment>(*it);
+ assert(DF.fixup_begin() == DF.fixup_end() &&
+ "Cannot have fixups in virtual section!");
+ for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
+ assert(DF.getContents()[i] == 0 &&
+ "Invalid data value for virtual section!");
+ break;
+ }
case MCFragment::FT_Align:
- 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() ||
+ !cast<MCAlignFragment>(it)->getValue()) &&
"Invalid align in virtual section!");
break;
case MCFragment::FT_Fill:
ie = SD->end(); it != ie; ++it)
WriteFragmentData(*this, Layout, *it, OW);
- assert(OW->getStream().tell() - Start == Layout.getSectionFileSize(SD));
+ assert(OW->getStream().tell() - Start == Layout.getSectionAddressSize(SD));
}
-void MCAssembler::Finish() {
+
+uint64_t MCAssembler::HandleFixup(MCObjectWriter &Writer,
+ const MCAsmLayout &Layout,
+ MCFragment &F,
+ const MCFixup &Fixup) {
+ // Evaluate the fixup.
+ MCValue Target;
+ uint64_t FixedValue;
+ if (!EvaluateFixup(Writer, 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.
+ Writer.RecordRelocation(*this, Layout, &F, Fixup, Target, FixedValue);
+ }
+ return FixedValue;
+ }
+
+void MCAssembler::Finish(MCObjectWriter *Writer) {
DEBUG_WITH_TYPE("mc-dump", {
llvm::errs() << "assembler backend - pre-layout\n--\n";
dump(); });
- // Assign section and fragment ordinals, all subsequent backend code is
- // responsible for updating these in place.
+ // Create the layout object.
+ MCAsmLayout Layout(*this);
+
+
+
+ // Create dummy fragments and assign section ordinals.
unsigned SectionIndex = 0;
- unsigned FragmentIndex = 0;
for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
- it->setOrdinal(SectionIndex++);
+ // Create dummy fragments to eliminate any empty sections, this simplifies
+ // layout.
+ if (it->getFragmentList().empty())
+ new MCDataFragment(it);
- for (MCSectionData::iterator it2 = it->begin(),
- ie2 = it->end(); it2 != ie2; ++it2)
- it2->setOrdinal(FragmentIndex++);
+ it->setOrdinal(SectionIndex++);
}
- // 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) {
+ // 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);
- // 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;
+ unsigned FragmentIndex = 0;
+ for (MCSectionData::iterator it2 = SD->begin(),
+ ie2 = SD->end(); it2 != ie2; ++it2)
+ it2->setLayoutOrder(FragmentIndex++);
+ }
- // 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);
+ llvm::OwningPtr<MCObjectWriter> OwnWriter(0);
+ if (Writer == 0) {
+ //no custom Writer_ : create the default one life-managed by OwningPtr
+ OwnWriter.reset(getBackend().createObjectWriter(OS));
+ Writer = OwnWriter.get();
+ if (!Writer)
+ report_fatal_error("unable to create object writer!");
}
// Layout until everything fits.
- while (LayoutOnce(Layout))
+ while (LayoutOnce(*Writer, Layout))
continue;
DEBUG_WITH_TYPE("mc-dump", {
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);
+ Writer->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);
+ if (DF) {
+ for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
+ ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
+ MCFixup &Fixup = *it3;
+ uint64_t FixedValue = HandleFixup(*Writer, Layout, *DF, Fixup);
+ getBackend().ApplyFixup(Fixup, DF->getContents().data(),
+ DF->getContents().size(), FixedValue);
+ }
+ }
+ MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
+ if (IF) {
+ for (MCInstFragment::fixup_iterator it3 = IF->fixup_begin(),
+ ie3 = IF->fixup_end(); it3 != ie3; ++it3) {
+ MCFixup &Fixup = *it3;
+ uint64_t FixedValue = HandleFixup(*Writer, Layout, *IF, Fixup);
+ getBackend().ApplyFixup(Fixup, IF->getCode().data(),
+ IF->getCode().size(), FixedValue);
}
-
- getBackend().ApplyFixup(Fixup, *DF, FixedValue);
}
}
}
// Write the object file.
Writer->WriteObject(*this, Layout);
- OS.flush();
stats::ObjectBytes += OS.tell() - StartOffset;
}
-bool MCAssembler::FixupNeedsRelaxation(const MCAsmFixup &Fixup,
+bool MCAssembler::FixupNeedsRelaxation(const MCObjectWriter &Writer,
+ const MCFixup &Fixup,
const MCFragment *DF,
const MCAsmLayout &Layout) const {
if (getRelaxAll())
// If we cannot resolve the fixup value, it requires relaxation.
MCValue Target;
uint64_t Value;
- if (!EvaluateFixup(Layout, Fixup, DF, Target, Value))
+ if (!EvaluateFixup(Writer, 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));
}
-bool MCAssembler::FragmentNeedsRelaxation(const MCInstFragment *IF,
+bool MCAssembler::FragmentNeedsRelaxation(const MCObjectWriter &Writer,
+ const MCInstFragment *IF,
const MCAsmLayout &Layout) const {
// If this inst doesn't ever need relaxation, ignore it. This occurs when we
// are intentionally pushing out inst fragments, or because we relaxed a
// previous instruction to one that doesn't need relaxation.
- if (!getBackend().MayNeedRelaxation(IF->getInst(), IF->getFixups()))
+ if (!getBackend().MayNeedRelaxation(IF->getInst()))
return false;
for (MCInstFragment::const_fixup_iterator it = IF->fixup_begin(),
ie = IF->fixup_end(); it != ie; ++it)
- if (FixupNeedsRelaxation(*it, IF, Layout))
+ if (FixupNeedsRelaxation(Writer, *it, IF, Layout))
return true;
return false;
}
-bool MCAssembler::LayoutOnce(MCAsmLayout &Layout) {
- ++stats::RelaxationSteps;
+bool MCAssembler::RelaxInstruction(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout,
+ MCInstFragment &IF) {
+ if (!FragmentNeedsRelaxation(Writer, &IF, Layout))
+ return false;
+
+ ++stats::RelaxedInstructions;
+
+ // FIXME-PERF: We could immediately lower out instructions if we can tell
+ // they are fully resolved, to avoid retesting on later passes.
+
+ // Relax the fragment.
+
+ MCInst Relaxed;
+ getBackend().RelaxInstruction(IF.getInst(), Relaxed);
+
+ // Encode the new instruction.
+ //
+ // FIXME-PERF: If it matters, we could let the target do this. It can
+ // probably do so more efficiently in many cases.
+ SmallVector<MCFixup, 4> Fixups;
+ SmallString<256> Code;
+ raw_svector_ostream VecOS(Code);
+ getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups);
+ VecOS.flush();
+
+ // Update the instruction fragment.
+ IF.setInst(Relaxed);
+ IF.getCode() = Code;
+ IF.getFixups().clear();
+ // FIXME: Eliminate copy.
+ for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
+ IF.getFixups().push_back(Fixups[i]);
+
+ return true;
+}
- // Layout the sections in order.
- for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i)
- LayoutSection(Layout, i);
+bool MCAssembler::RelaxOrg(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout,
+ MCOrgFragment &OF) {
+ 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 Offset = TargetLocation - FragmentOffset;
+ if (Offset < 0 || Offset >= 0x40000000)
+ report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
+ "' (at offset '" + Twine(FragmentOffset) + "')");
+
+ unsigned OldSize = OF.getSize();
+ OF.setSize(Offset);
+ return OldSize != OF.getSize();
+}
+
+bool MCAssembler::RelaxLEB(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout,
+ MCLEBFragment &LF) {
+ int64_t Value = 0;
+ uint64_t OldSize = LF.getContents().size();
+ LF.getValue().EvaluateAsAbsolute(Value, Layout);
+ SmallString<8> &Data = LF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ if (LF.isSigned())
+ MCObjectWriter::EncodeSLEB128(Value, OSE);
+ else
+ MCObjectWriter::EncodeULEB128(Value, OSE);
+ OSE.flush();
+ return OldSize != LF.getContents().size();
+}
+
+bool MCAssembler::RelaxDwarfLineAddr(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout,
+ MCDwarfLineAddrFragment &DF) {
+ int64_t AddrDelta = 0;
+ uint64_t OldSize = DF.getContents().size();
+ DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
+ int64_t LineDelta;
+ LineDelta = DF.getLineDelta();
+ SmallString<8> &Data = DF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
+
+bool MCAssembler::RelaxAlignment(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout,
+ MCAlignFragment &AF) {
+ unsigned Offset = Layout.getFragmentOffset(&AF);
+ unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
+ if (Size > AF.getMaxBytesToEmit())
+ Size = 0;
+ unsigned OldSize = AF.getSize();
+ AF.setSize(Size);
+ return OldSize != Size;
+}
+
+bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout) {
+ ++stats::RelaxationSteps;
// Scan for fragments that need relaxation.
bool WasRelaxed = false;
for (iterator it = begin(), ie = end(); it != ie; ++it) {
MCSectionData &SD = *it;
+ MCFragment *FirstInvalidFragment = NULL;
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()));
+ // Check if this is an fragment that needs relaxation.
+ bool relaxedFrag = false;
+ switch(it2->getKind()) {
+ default:
+ break;
+ case MCFragment::FT_Align:
+ relaxedFrag = RelaxAlignment(Writer, Layout,
+ *cast<MCAlignFragment>(it2));
+ break;
+ case MCFragment::FT_Inst:
+ relaxedFrag = RelaxInstruction(Writer, Layout,
+ *cast<MCInstFragment>(it2));
+ break;
+ case MCFragment::FT_Org:
+ relaxedFrag = RelaxOrg(Writer, Layout, *cast<MCOrgFragment>(it2));
+ break;
+ case MCFragment::FT_Dwarf:
+ relaxedFrag = RelaxDwarfLineAddr(Writer, Layout,
+ *cast<MCDwarfLineAddrFragment>(it2));
+ break;
+ case MCFragment::FT_LEB:
+ relaxedFrag = RelaxLEB(Writer, Layout, *cast<MCLEBFragment>(it2));
+ break;
}
-
- // 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;
+ // Update the layout, and remember that we relaxed.
+ if (relaxedFrag && !FirstInvalidFragment)
+ FirstInvalidFragment = it2;
+ WasRelaxed |= relaxedFrag;
}
+ if (FirstInvalidFragment)
+ Layout.Invalidate(FirstInvalidFragment);
}
return WasRelaxed;
}
void MCAssembler::FinishLayout(MCAsmLayout &Layout) {
- // Lower out any instruction fragments, to simplify the fixup application and
- // output.
- //
- // 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->setOrdinal(IF->getOrdinal());
- 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;
- }
+ // 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());
}
}
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;
}
void MCFragment::dump() {
raw_ostream &OS = llvm::errs();
- OS << "<MCFragment " << (void*) this << " Offset:" << Offset
- << " EffectiveSize:" << EffectiveSize << ">";
-}
-
-void MCAlignFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- 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() << ">";
-}
+ OS << "<";
+ switch (getKind()) {
+ case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
+ case MCFragment::FT_Data: OS << "MCDataFragment"; break;
+ case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
+ case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
+ case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
+ case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
+ case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
+ }
-void MCDataFragment::dump() {
- raw_ostream &OS = llvm::errs();
+ OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
+ << " Offset:" << Offset << ">";
- 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->getFixups().empty()) {
+ OS << ",\n ";
+ OS << " Fixups:[";
+ for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
+ ie = DF->fixup_end(); it != ie; ++it) {
+ if (it != DF->fixup_begin()) OS << ",\n ";
+ OS << *it;
+ }
+ OS << "]";
+ }
+ break;
+ }
+ case MCFragment::FT_Fill: {
+ const MCFillFragment *FF = cast<MCFillFragment>(this);
+ OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
+ << " Size:" << FF->getSize();
+ break;
+ }
+ case MCFragment::FT_Inst: {
+ const MCInstFragment *IF = cast<MCInstFragment>(this);
+ OS << "\n ";
+ OS << " Inst:";
+ IF->getInst().dump_pretty(OS);
+ break;
+ }
+ case MCFragment::FT_Org: {
+ const MCOrgFragment *OF = cast<MCOrgFragment>(this);
+ OS << "\n ";
+ OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
+ break;
+ }
+ case MCFragment::FT_Dwarf: {
+ const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
+ OS << "\n ";
+ OS << " AddrDelta:" << OF->getAddrDelta()
+ << " LineDelta:" << OF->getLineDelta();
+ break;
+ }
+ case MCFragment::FT_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()
- << " Size:" << getSize() << ">";
-}
-
-void MCInstFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCInstFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Inst:";
- getInst().dump_pretty(OS);
OS << ">";
}
-void MCOrgFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCOrgFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Offset:" << getOffset() << " Value:" << getValue() << ">";
-}
-
void MCSectionData::dump() {
raw_ostream &OS = llvm::errs();
OS << "<MCSectionData";
- OS << " Alignment:" << getAlignment() << " Address:" << Address
- << " Fragments:[\n ";
+ OS << " Alignment:" << getAlignment() << " Fragments:[\n ";
for (iterator it = begin(), ie = end(); it != ie; ++it) {
if (it != begin()) OS << ",\n ";
it->dump();
projects / oota-llvm.git / blobdiff