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)),
+ EffectiveSize(~UINT64_C(0))
{
if (Parent)
Parent->getFragmentList().push_back(this);
uint64_t _Offset, MCAssembler *A)
: Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
IsExternal(false), IsPrivateExtern(false),
- CommonSize(0), CommonAlign(0), Flags(0), Index(0)
+ CommonSize(0), SymbolSize(0), CommonAlign(0),
+ Flags(0), Index(0)
{
if (A)
A->getSymbolList().push_back(this);
/* *** */
MCAssembler::MCAssembler(MCContext &_Context, TargetAsmBackend &_Backend,
- MCCodeEmitter &_Emitter, raw_ostream &_OS)
+ MCCodeEmitter &_Emitter, bool _PadSectionToAlignment,
+ raw_ostream &_OS)
: Context(_Context), Backend(_Backend), Emitter(_Emitter),
- OS(_OS), RelaxAll(false), SubsectionsViaSymbols(false)
+ OS(_OS), RelaxAll(false), SubsectionsViaSymbols(false),
+ PadSectionToAlignment(_PadSectionToAlignment)
{
}
MCAssembler::~MCAssembler() {
}
-static bool isScatteredFixupFullyResolvedSimple(const MCAssembler &Asm,
- const MCFixup &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 MCFixup &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 MCSymbol &Symbol) const {
// Non-temporary labels should always be visible to the linker.
if (!Symbol.isTemporary())
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->getSymbol()))
return SD;
return SD->getFragment()->getAtom();
}
-bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout,
+bool MCAssembler::EvaluateFixup(const MCObjectWriter &Writer,
+ const MCAsmLayout &Layout,
const MCFixup &Fixup, const MCFragment *DF,
MCValue &Target, uint64_t &Value) const {
++stats::EvaluateFixup;
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);
if (IsPCRel)
Value -= Layout.getFragmentAddress(DF) + Fixup.getOffset();
// FIXME: We need a way to communicate this error.
int64_t Offset = TargetLocation - FragmentOffset;
- if (Offset < 0)
+ if (Offset < 0 || Offset >= 0x40000000)
report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
- "' (at offset '" + Twine(FragmentOffset) + "'");
+ "' (at offset '" + Twine(FragmentOffset) + "')");
return Offset;
}
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:
assert(OW->getStream().tell() - Start == Layout.getSectionFileSize(SD));
}
-void MCAssembler::Finish() {
+void MCAssembler::AddSectionToTheEnd(const MCObjectWriter &Writer,
+ MCSectionData &SD, MCAsmLayout &Layout) {
+ // Create dummy fragments and assign section ordinals.
+ unsigned SectionIndex = 0;
+ for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it)
+ SectionIndex++;
+
+ SD.setOrdinal(SectionIndex);
+
+ // Assign layout order indices to sections and fragments.
+ unsigned FragmentIndex = 0;
+ unsigned i = 0;
+ for (unsigned e = Layout.getSectionOrder().size(); i != e; ++i) {
+ MCSectionData *SD = Layout.getSectionOrder()[i];
+
+ for (MCSectionData::iterator it2 = SD->begin(),
+ ie2 = SD->end(); it2 != ie2; ++it2)
+ FragmentIndex++;
+ }
+
+ SD.setLayoutOrder(i);
+ for (MCSectionData::iterator it2 = SD.begin(),
+ ie2 = SD.end(); it2 != ie2; ++it2) {
+ it2->setLayoutOrder(FragmentIndex++);
+ }
+ Layout.getSectionOrder().push_back(&SD);
+
+ Layout.LayoutSection(&SD);
+
+ // Layout until everything fits.
+ while (LayoutOnce(Writer, Layout))
+ continue;
+
+}
+
+void MCAssembler::Finish(MCObjectWriter *Writer) {
DEBUG_WITH_TYPE("mc-dump", {
llvm::errs() << "assembler backend - pre-layout\n--\n";
dump(); });
// 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];
+ if (PadSectionToAlignment) {
+ 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 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;
+ // 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);
+ // 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.
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++);
}
it2->setLayoutOrder(FragmentIndex++);
}
+ 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).
// Evaluate the fixup.
MCValue Target;
uint64_t FixedValue;
- if (!EvaluateFixup(Layout, Fixup, DF, Target, FixedValue)) {
+ if (!EvaluateFixup(*Writer, 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.
stats::ObjectBytes += OS.tell() - StartOffset;
}
-bool MCAssembler::FixupNeedsRelaxation(const MCFixup &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
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) {
+bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout) {
++stats::RelaxationSteps;
// Layout the sections in order.
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))
+ if (!IF || !FragmentNeedsRelaxation(Writer, IF, Layout))
continue;
++stats::RelaxedInstructions;
projects / oota-llvm.git / blobdiff