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These are strictly utilities for registering targets and components. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138450 91177308-0d34-0410-b5e6-96231b3b80d8
978 lines
32 KiB
C++
978 lines
32 KiB
C++
//===- lib/MC/MCAssembler.cpp - Assembler Backend Implementation ----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "assembler"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCCodeEmitter.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSection.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/MC/MCDwarf.h"
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#include "llvm/MC/MCAsmBackend.h"
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#include "llvm/ADT/OwningPtr.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/TargetRegistry.h"
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using namespace llvm;
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namespace {
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namespace stats {
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STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
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STATISTIC(EvaluateFixup, "Number of evaluated fixups");
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STATISTIC(FragmentLayouts, "Number of fragment layouts");
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STATISTIC(ObjectBytes, "Number of emitted object file bytes");
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STATISTIC(RelaxationSteps, "Number of assembler layout and relaxation steps");
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STATISTIC(RelaxedInstructions, "Number of relaxed instructions");
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}
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}
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// FIXME FIXME FIXME: There are number of places in this file where we convert
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// what is a 64-bit assembler value used for computation into a value in the
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// object file, which may truncate it. We should detect that truncation where
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// invalid and report errors back.
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/* *** */
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MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
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: Assembler(Asm), LastValidFragment()
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{
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// Compute the section layout order. Virtual sections must go last.
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for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
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if (!it->getSection().isVirtualSection())
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SectionOrder.push_back(&*it);
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for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
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if (it->getSection().isVirtualSection())
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SectionOrder.push_back(&*it);
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}
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bool MCAsmLayout::isFragmentUpToDate(const MCFragment *F) const {
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const MCSectionData &SD = *F->getParent();
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const MCFragment *LastValid = LastValidFragment.lookup(&SD);
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if (!LastValid)
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return false;
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assert(LastValid->getParent() == F->getParent());
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return F->getLayoutOrder() <= LastValid->getLayoutOrder();
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}
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void MCAsmLayout::Invalidate(MCFragment *F) {
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// If this fragment wasn't already up-to-date, we don't need to do anything.
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if (!isFragmentUpToDate(F))
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return;
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// Otherwise, reset the last valid fragment to this fragment.
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const MCSectionData &SD = *F->getParent();
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LastValidFragment[&SD] = F;
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}
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void MCAsmLayout::EnsureValid(const MCFragment *F) const {
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MCSectionData &SD = *F->getParent();
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MCFragment *Cur = LastValidFragment[&SD];
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if (!Cur)
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Cur = &*SD.begin();
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else
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Cur = Cur->getNextNode();
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// Advance the layout position until the fragment is up-to-date.
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while (!isFragmentUpToDate(F)) {
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const_cast<MCAsmLayout*>(this)->LayoutFragment(Cur);
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Cur = Cur->getNextNode();
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}
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}
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uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
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EnsureValid(F);
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assert(F->Offset != ~UINT64_C(0) && "Address not set!");
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return F->Offset;
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}
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uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
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const MCSymbol &S = SD->getSymbol();
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// If this is a variable, then recursively evaluate now.
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if (S.isVariable()) {
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MCValue Target;
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if (!S.getVariableValue()->EvaluateAsRelocatable(Target, *this))
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report_fatal_error("unable to evaluate offset for variable '" +
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S.getName() + "'");
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// Verify that any used symbols are defined.
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if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined())
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report_fatal_error("unable to evaluate offset to undefined symbol '" +
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Target.getSymA()->getSymbol().getName() + "'");
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if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined())
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report_fatal_error("unable to evaluate offset to undefined symbol '" +
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Target.getSymB()->getSymbol().getName() + "'");
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uint64_t Offset = Target.getConstant();
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if (Target.getSymA())
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Offset += getSymbolOffset(&Assembler.getSymbolData(
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Target.getSymA()->getSymbol()));
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if (Target.getSymB())
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Offset -= getSymbolOffset(&Assembler.getSymbolData(
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Target.getSymB()->getSymbol()));
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return Offset;
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}
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assert(SD->getFragment() && "Invalid getOffset() on undefined symbol!");
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return getFragmentOffset(SD->getFragment()) + SD->getOffset();
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}
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uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
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// The size is the last fragment's end offset.
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const MCFragment &F = SD->getFragmentList().back();
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return getFragmentOffset(&F) + getAssembler().ComputeFragmentSize(*this, F);
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}
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uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
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// Virtual sections have no file size.
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if (SD->getSection().isVirtualSection())
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return 0;
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// Otherwise, the file size is the same as the address space size.
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return getSectionAddressSize(SD);
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}
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/* *** */
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MCFragment::MCFragment() : Kind(FragmentType(~0)) {
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}
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MCFragment::~MCFragment() {
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}
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MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
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: Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
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{
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if (Parent)
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Parent->getFragmentList().push_back(this);
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}
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/* *** */
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MCSectionData::MCSectionData() : Section(0) {}
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MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
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: Section(&_Section),
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Ordinal(~UINT32_C(0)),
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Alignment(1),
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HasInstructions(false)
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{
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if (A)
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A->getSectionList().push_back(this);
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}
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/* *** */
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MCSymbolData::MCSymbolData() : Symbol(0) {}
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MCSymbolData::MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment,
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uint64_t _Offset, MCAssembler *A)
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: Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
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IsExternal(false), IsPrivateExtern(false),
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CommonSize(0), SymbolSize(0), CommonAlign(0),
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Flags(0), Index(0)
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{
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if (A)
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A->getSymbolList().push_back(this);
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}
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/* *** */
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MCAssembler::MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
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MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
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raw_ostream &OS_)
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: Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
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OS(OS_), RelaxAll(false), NoExecStack(false), SubsectionsViaSymbols(false)
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{
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}
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MCAssembler::~MCAssembler() {
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}
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bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
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// Non-temporary labels should always be visible to the linker.
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if (!Symbol.isTemporary())
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return true;
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// Absolute temporary labels are never visible.
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if (!Symbol.isInSection())
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return false;
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// Otherwise, check if the section requires symbols even for temporary labels.
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return getBackend().doesSectionRequireSymbols(Symbol.getSection());
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}
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const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
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// Linker visible symbols define atoms.
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if (isSymbolLinkerVisible(SD->getSymbol()))
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return SD;
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// Absolute and undefined symbols have no defining atom.
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if (!SD->getFragment())
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return 0;
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// Non-linker visible symbols in sections which can't be atomized have no
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// defining atom.
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if (!getBackend().isSectionAtomizable(
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SD->getFragment()->getParent()->getSection()))
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return 0;
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// Otherwise, return the atom for the containing fragment.
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return SD->getFragment()->getAtom();
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}
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bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout,
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const MCFixup &Fixup, const MCFragment *DF,
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MCValue &Target, uint64_t &Value) const {
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++stats::EvaluateFixup;
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if (!Fixup.getValue()->EvaluateAsRelocatable(Target, Layout))
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report_fatal_error("expected relocatable expression");
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bool IsPCRel = Backend.getFixupKindInfo(
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Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
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bool IsResolved;
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if (IsPCRel) {
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if (Target.getSymB()) {
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IsResolved = false;
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} else if (!Target.getSymA()) {
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IsResolved = false;
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} else {
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const MCSymbolRefExpr *A = Target.getSymA();
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const MCSymbol &SA = A->getSymbol();
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if (A->getKind() != MCSymbolRefExpr::VK_None ||
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SA.AliasedSymbol().isUndefined()) {
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IsResolved = false;
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} else {
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const MCSymbolData &DataA = getSymbolData(SA);
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IsResolved =
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getWriter().IsSymbolRefDifferenceFullyResolvedImpl(*this, DataA,
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*DF, false, true);
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}
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}
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} else {
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IsResolved = Target.isAbsolute();
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}
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Value = Target.getConstant();
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bool IsThumb = false;
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if (const MCSymbolRefExpr *A = Target.getSymA()) {
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const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
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if (Sym.isDefined())
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Value += Layout.getSymbolOffset(&getSymbolData(Sym));
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if (isThumbFunc(&Sym))
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IsThumb = true;
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}
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if (const MCSymbolRefExpr *B = Target.getSymB()) {
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const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
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if (Sym.isDefined())
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Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
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}
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bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
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MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
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assert((ShouldAlignPC ? IsPCRel : true) &&
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"FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
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if (IsPCRel) {
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uint32_t Offset = Layout.getFragmentOffset(DF) + Fixup.getOffset();
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// A number of ARM fixups in Thumb mode require that the effective PC
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// address be determined as the 32-bit aligned version of the actual offset.
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if (ShouldAlignPC) Offset &= ~0x3;
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Value -= Offset;
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}
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// ARM fixups based from a thumb function address need to have the low
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// bit set. The actual value is always at least 16-bit aligned, so the
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// low bit is normally clear and available for use as an ISA flag for
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// interworking.
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if (IsThumb)
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Value |= 1;
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return IsResolved;
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}
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uint64_t MCAssembler::ComputeFragmentSize(const MCAsmLayout &Layout,
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const MCFragment &F) const {
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switch (F.getKind()) {
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case MCFragment::FT_Data:
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return cast<MCDataFragment>(F).getContents().size();
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case MCFragment::FT_Fill:
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return cast<MCFillFragment>(F).getSize();
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case MCFragment::FT_Inst:
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return cast<MCInstFragment>(F).getInstSize();
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case MCFragment::FT_LEB:
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return cast<MCLEBFragment>(F).getContents().size();
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case MCFragment::FT_Align: {
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const MCAlignFragment &AF = cast<MCAlignFragment>(F);
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unsigned Offset = Layout.getFragmentOffset(&AF);
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unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
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if (Size > AF.getMaxBytesToEmit())
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return 0;
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return Size;
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}
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case MCFragment::FT_Org: {
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MCOrgFragment &OF = cast<MCOrgFragment>(F);
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int64_t TargetLocation;
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if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
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report_fatal_error("expected assembly-time absolute expression");
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// FIXME: We need a way to communicate this error.
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uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
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int64_t Size = TargetLocation - FragmentOffset;
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if (Size < 0 || Size >= 0x40000000)
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report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
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"' (at offset '" + Twine(FragmentOffset) + "')");
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return Size;
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}
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case MCFragment::FT_Dwarf:
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return cast<MCDwarfLineAddrFragment>(F).getContents().size();
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case MCFragment::FT_DwarfFrame:
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return cast<MCDwarfCallFrameFragment>(F).getContents().size();
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}
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assert(0 && "invalid fragment kind");
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return 0;
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}
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void MCAsmLayout::LayoutFragment(MCFragment *F) {
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MCFragment *Prev = F->getPrevNode();
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// We should never try to recompute something which is up-to-date.
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assert(!isFragmentUpToDate(F) && "Attempt to recompute up-to-date fragment!");
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// We should never try to compute the fragment layout if it's predecessor
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// isn't up-to-date.
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assert((!Prev || isFragmentUpToDate(Prev)) &&
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"Attempt to compute fragment before it's predecessor!");
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++stats::FragmentLayouts;
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// Compute fragment offset and size.
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uint64_t Offset = 0;
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if (Prev)
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Offset += Prev->Offset + getAssembler().ComputeFragmentSize(*this, *Prev);
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F->Offset = Offset;
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LastValidFragment[F->getParent()] = F;
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}
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/// WriteFragmentData - Write the \arg F data to the output file.
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static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
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const MCFragment &F) {
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MCObjectWriter *OW = &Asm.getWriter();
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uint64_t Start = OW->getStream().tell();
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(void) Start;
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++stats::EmittedFragments;
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// FIXME: Embed in fragments instead?
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uint64_t FragmentSize = Asm.ComputeFragmentSize(Layout, F);
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switch (F.getKind()) {
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case MCFragment::FT_Align: {
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MCAlignFragment &AF = cast<MCAlignFragment>(F);
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uint64_t Count = FragmentSize / AF.getValueSize();
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assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
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// FIXME: This error shouldn't actually occur (the front end should emit
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// multiple .align directives to enforce the semantics it wants), but is
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// severe enough that we want to report it. How to handle this?
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if (Count * AF.getValueSize() != FragmentSize)
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report_fatal_error("undefined .align directive, value size '" +
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Twine(AF.getValueSize()) +
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"' is not a divisor of padding size '" +
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Twine(FragmentSize) + "'");
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// See if we are aligning with nops, and if so do that first to try to fill
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// the Count bytes. Then if that did not fill any bytes or there are any
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// bytes left to fill use the the Value and ValueSize to fill the rest.
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// If we are aligning with nops, ask that target to emit the right data.
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if (AF.hasEmitNops()) {
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if (!Asm.getBackend().WriteNopData(Count, OW))
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report_fatal_error("unable to write nop sequence of " +
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Twine(Count) + " bytes");
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break;
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}
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// Otherwise, write out in multiples of the value size.
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for (uint64_t i = 0; i != Count; ++i) {
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switch (AF.getValueSize()) {
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default:
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assert(0 && "Invalid size!");
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case 1: OW->Write8 (uint8_t (AF.getValue())); break;
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case 2: OW->Write16(uint16_t(AF.getValue())); break;
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case 4: OW->Write32(uint32_t(AF.getValue())); break;
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case 8: OW->Write64(uint64_t(AF.getValue())); break;
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}
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}
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break;
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}
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case MCFragment::FT_Data: {
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MCDataFragment &DF = cast<MCDataFragment>(F);
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assert(FragmentSize == DF.getContents().size() && "Invalid size!");
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OW->WriteBytes(DF.getContents().str());
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break;
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}
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case MCFragment::FT_Fill: {
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MCFillFragment &FF = cast<MCFillFragment>(F);
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assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");
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for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
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switch (FF.getValueSize()) {
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default:
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assert(0 && "Invalid size!");
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case 1: OW->Write8 (uint8_t (FF.getValue())); break;
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case 2: OW->Write16(uint16_t(FF.getValue())); break;
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case 4: OW->Write32(uint32_t(FF.getValue())); break;
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case 8: OW->Write64(uint64_t(FF.getValue())); break;
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}
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}
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break;
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}
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case MCFragment::FT_Inst: {
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MCInstFragment &IF = cast<MCInstFragment>(F);
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OW->WriteBytes(StringRef(IF.getCode().begin(), IF.getCode().size()));
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break;
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}
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case MCFragment::FT_LEB: {
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MCLEBFragment &LF = cast<MCLEBFragment>(F);
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OW->WriteBytes(LF.getContents().str());
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break;
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}
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case MCFragment::FT_Org: {
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MCOrgFragment &OF = cast<MCOrgFragment>(F);
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for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
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OW->Write8(uint8_t(OF.getValue()));
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break;
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}
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case MCFragment::FT_Dwarf: {
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const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
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OW->WriteBytes(OF.getContents().str());
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break;
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}
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case MCFragment::FT_DwarfFrame: {
|
|
const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
|
|
OW->WriteBytes(CF.getContents().str());
|
|
break;
|
|
}
|
|
}
|
|
|
|
assert(OW->getStream().tell() - Start == FragmentSize);
|
|
}
|
|
|
|
void MCAssembler::WriteSectionData(const MCSectionData *SD,
|
|
const MCAsmLayout &Layout) const {
|
|
// Ignore virtual sections.
|
|
if (SD->getSection().isVirtualSection()) {
|
|
assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
|
|
|
|
// Check that contents are only things legal inside a virtual section.
|
|
for (MCSectionData::const_iterator it = SD->begin(),
|
|
ie = SD->end(); it != ie; ++it) {
|
|
switch (it->getKind()) {
|
|
default:
|
|
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:
|
|
// Check that we aren't trying to write a non-zero value into a virtual
|
|
// section.
|
|
assert((!cast<MCAlignFragment>(it)->getValueSize() ||
|
|
!cast<MCAlignFragment>(it)->getValue()) &&
|
|
"Invalid align in virtual section!");
|
|
break;
|
|
case MCFragment::FT_Fill:
|
|
assert(!cast<MCFillFragment>(it)->getValueSize() &&
|
|
"Invalid fill in virtual section!");
|
|
break;
|
|
}
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
uint64_t Start = getWriter().getStream().tell();
|
|
(void) Start;
|
|
|
|
for (MCSectionData::const_iterator it = SD->begin(),
|
|
ie = SD->end(); it != ie; ++it)
|
|
WriteFragmentData(*this, Layout, *it);
|
|
|
|
assert(getWriter().getStream().tell() - Start ==
|
|
Layout.getSectionAddressSize(SD));
|
|
}
|
|
|
|
|
|
uint64_t MCAssembler::HandleFixup(const MCAsmLayout &Layout,
|
|
MCFragment &F,
|
|
const MCFixup &Fixup) {
|
|
// Evaluate the fixup.
|
|
MCValue Target;
|
|
uint64_t FixedValue;
|
|
if (!EvaluateFixup(Layout, Fixup, &F, Target, FixedValue)) {
|
|
// The fixup was unresolved, we need a relocation. Inform the object
|
|
// writer of the relocation, and give it an opportunity to adjust the
|
|
// fixup value if need be.
|
|
getWriter().RecordRelocation(*this, Layout, &F, Fixup, Target, FixedValue);
|
|
}
|
|
return FixedValue;
|
|
}
|
|
|
|
void MCAssembler::Finish() {
|
|
DEBUG_WITH_TYPE("mc-dump", {
|
|
llvm::errs() << "assembler backend - pre-layout\n--\n";
|
|
dump(); });
|
|
|
|
// Create the layout object.
|
|
MCAsmLayout Layout(*this);
|
|
|
|
// Create dummy fragments and assign section ordinals.
|
|
unsigned SectionIndex = 0;
|
|
for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
// Create dummy fragments to eliminate any empty sections, this simplifies
|
|
// layout.
|
|
if (it->getFragmentList().empty())
|
|
new MCDataFragment(it);
|
|
|
|
it->setOrdinal(SectionIndex++);
|
|
}
|
|
|
|
// Assign layout order indices to sections and fragments.
|
|
for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
|
|
MCSectionData *SD = Layout.getSectionOrder()[i];
|
|
SD->setLayoutOrder(i);
|
|
|
|
unsigned FragmentIndex = 0;
|
|
for (MCSectionData::iterator it2 = SD->begin(),
|
|
ie2 = SD->end(); it2 != ie2; ++it2)
|
|
it2->setLayoutOrder(FragmentIndex++);
|
|
}
|
|
|
|
// Layout until everything fits.
|
|
while (LayoutOnce(Layout))
|
|
continue;
|
|
|
|
DEBUG_WITH_TYPE("mc-dump", {
|
|
llvm::errs() << "assembler backend - post-relaxation\n--\n";
|
|
dump(); });
|
|
|
|
// Finalize the layout, including fragment lowering.
|
|
FinishLayout(Layout);
|
|
|
|
DEBUG_WITH_TYPE("mc-dump", {
|
|
llvm::errs() << "assembler backend - final-layout\n--\n";
|
|
dump(); });
|
|
|
|
uint64_t StartOffset = OS.tell();
|
|
|
|
// Allow the object writer a chance to perform post-layout binding (for
|
|
// example, to set the index fields in the symbol data).
|
|
getWriter().ExecutePostLayoutBinding(*this, Layout);
|
|
|
|
// Evaluate and apply the fixups, generating relocation entries as necessary.
|
|
for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
for (MCSectionData::iterator it2 = it->begin(),
|
|
ie2 = it->end(); it2 != ie2; ++it2) {
|
|
MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
|
|
if (DF) {
|
|
for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
|
|
ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
|
|
MCFixup &Fixup = *it3;
|
|
uint64_t FixedValue = HandleFixup(Layout, *DF, Fixup);
|
|
getBackend().ApplyFixup(Fixup, DF->getContents().data(),
|
|
DF->getContents().size(), FixedValue);
|
|
}
|
|
}
|
|
MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
|
|
if (IF) {
|
|
for (MCInstFragment::fixup_iterator it3 = IF->fixup_begin(),
|
|
ie3 = IF->fixup_end(); it3 != ie3; ++it3) {
|
|
MCFixup &Fixup = *it3;
|
|
uint64_t FixedValue = HandleFixup(Layout, *IF, Fixup);
|
|
getBackend().ApplyFixup(Fixup, IF->getCode().data(),
|
|
IF->getCode().size(), FixedValue);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Write the object file.
|
|
getWriter().WriteObject(*this, Layout);
|
|
|
|
stats::ObjectBytes += OS.tell() - StartOffset;
|
|
}
|
|
|
|
bool MCAssembler::FixupNeedsRelaxation(const MCFixup &Fixup,
|
|
const MCFragment *DF,
|
|
const MCAsmLayout &Layout) const {
|
|
if (getRelaxAll())
|
|
return true;
|
|
|
|
// If we cannot resolve the fixup value, it requires relaxation.
|
|
MCValue Target;
|
|
uint64_t Value;
|
|
if (!EvaluateFixup(Layout, Fixup, DF, Target, Value))
|
|
return true;
|
|
|
|
// 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));
|
|
}
|
|
|
|
bool MCAssembler::FragmentNeedsRelaxation(const MCInstFragment *IF,
|
|
const MCAsmLayout &Layout) const {
|
|
// If this inst doesn't ever need relaxation, ignore it. This occurs when we
|
|
// are intentionally pushing out inst fragments, or because we relaxed a
|
|
// previous instruction to one that doesn't need relaxation.
|
|
if (!getBackend().MayNeedRelaxation(IF->getInst()))
|
|
return false;
|
|
|
|
for (MCInstFragment::const_fixup_iterator it = IF->fixup_begin(),
|
|
ie = IF->fixup_end(); it != ie; ++it)
|
|
if (FixupNeedsRelaxation(*it, IF, Layout))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
bool MCAssembler::RelaxInstruction(MCAsmLayout &Layout,
|
|
MCInstFragment &IF) {
|
|
if (!FragmentNeedsRelaxation(&IF, Layout))
|
|
return false;
|
|
|
|
++stats::RelaxedInstructions;
|
|
|
|
// FIXME-PERF: We could immediately lower out instructions if we can tell
|
|
// they are fully resolved, to avoid retesting on later passes.
|
|
|
|
// Relax the fragment.
|
|
|
|
MCInst Relaxed;
|
|
getBackend().RelaxInstruction(IF.getInst(), Relaxed);
|
|
|
|
// Encode the new instruction.
|
|
//
|
|
// FIXME-PERF: If it matters, we could let the target do this. It can
|
|
// probably do so more efficiently in many cases.
|
|
SmallVector<MCFixup, 4> Fixups;
|
|
SmallString<256> Code;
|
|
raw_svector_ostream VecOS(Code);
|
|
getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups);
|
|
VecOS.flush();
|
|
|
|
// Update the instruction fragment.
|
|
IF.setInst(Relaxed);
|
|
IF.getCode() = Code;
|
|
IF.getFixups().clear();
|
|
// FIXME: Eliminate copy.
|
|
for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
|
|
IF.getFixups().push_back(Fixups[i]);
|
|
|
|
return true;
|
|
}
|
|
|
|
bool MCAssembler::RelaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
|
|
int64_t Value = 0;
|
|
uint64_t OldSize = LF.getContents().size();
|
|
bool IsAbs = LF.getValue().EvaluateAsAbsolute(Value, Layout);
|
|
(void)IsAbs;
|
|
assert(IsAbs);
|
|
SmallString<8> &Data = LF.getContents();
|
|
Data.clear();
|
|
raw_svector_ostream OSE(Data);
|
|
if (LF.isSigned())
|
|
MCObjectWriter::EncodeSLEB128(Value, OSE);
|
|
else
|
|
MCObjectWriter::EncodeULEB128(Value, OSE);
|
|
OSE.flush();
|
|
return OldSize != LF.getContents().size();
|
|
}
|
|
|
|
bool MCAssembler::RelaxDwarfLineAddr(MCAsmLayout &Layout,
|
|
MCDwarfLineAddrFragment &DF) {
|
|
int64_t AddrDelta = 0;
|
|
uint64_t OldSize = DF.getContents().size();
|
|
bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
|
|
(void)IsAbs;
|
|
assert(IsAbs);
|
|
int64_t LineDelta;
|
|
LineDelta = DF.getLineDelta();
|
|
SmallString<8> &Data = DF.getContents();
|
|
Data.clear();
|
|
raw_svector_ostream OSE(Data);
|
|
MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OSE);
|
|
OSE.flush();
|
|
return OldSize != Data.size();
|
|
}
|
|
|
|
bool MCAssembler::RelaxDwarfCallFrameFragment(MCAsmLayout &Layout,
|
|
MCDwarfCallFrameFragment &DF) {
|
|
int64_t AddrDelta = 0;
|
|
uint64_t OldSize = DF.getContents().size();
|
|
bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
|
|
(void)IsAbs;
|
|
assert(IsAbs);
|
|
SmallString<8> &Data = DF.getContents();
|
|
Data.clear();
|
|
raw_svector_ostream OSE(Data);
|
|
MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OSE);
|
|
OSE.flush();
|
|
return OldSize != Data.size();
|
|
}
|
|
|
|
bool MCAssembler::LayoutSectionOnce(MCAsmLayout &Layout,
|
|
MCSectionData &SD) {
|
|
MCFragment *FirstInvalidFragment = NULL;
|
|
// Scan for fragments that need relaxation.
|
|
for (MCSectionData::iterator it2 = SD.begin(),
|
|
ie2 = SD.end(); it2 != ie2; ++it2) {
|
|
// Check if this is an fragment that needs relaxation.
|
|
bool relaxedFrag = false;
|
|
switch(it2->getKind()) {
|
|
default:
|
|
break;
|
|
case MCFragment::FT_Inst:
|
|
relaxedFrag = RelaxInstruction(Layout, *cast<MCInstFragment>(it2));
|
|
break;
|
|
case MCFragment::FT_Dwarf:
|
|
relaxedFrag = RelaxDwarfLineAddr(Layout,
|
|
*cast<MCDwarfLineAddrFragment>(it2));
|
|
break;
|
|
case MCFragment::FT_DwarfFrame:
|
|
relaxedFrag =
|
|
RelaxDwarfCallFrameFragment(Layout,
|
|
*cast<MCDwarfCallFrameFragment>(it2));
|
|
break;
|
|
case MCFragment::FT_LEB:
|
|
relaxedFrag = RelaxLEB(Layout, *cast<MCLEBFragment>(it2));
|
|
break;
|
|
}
|
|
// Update the layout, and remember that we relaxed.
|
|
if (relaxedFrag && !FirstInvalidFragment)
|
|
FirstInvalidFragment = it2;
|
|
}
|
|
if (FirstInvalidFragment) {
|
|
Layout.Invalidate(FirstInvalidFragment);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool MCAssembler::LayoutOnce(MCAsmLayout &Layout) {
|
|
++stats::RelaxationSteps;
|
|
|
|
bool WasRelaxed = false;
|
|
for (iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
MCSectionData &SD = *it;
|
|
while(LayoutSectionOnce(Layout, SD))
|
|
WasRelaxed = true;
|
|
}
|
|
|
|
return WasRelaxed;
|
|
}
|
|
|
|
void MCAssembler::FinishLayout(MCAsmLayout &Layout) {
|
|
// The layout is done. Mark every fragment as valid.
|
|
for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
|
|
Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
|
|
}
|
|
}
|
|
|
|
// Debugging methods
|
|
|
|
namespace llvm {
|
|
|
|
raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
|
|
OS << "<MCFixup" << " Offset:" << AF.getOffset()
|
|
<< " Value:" << *AF.getValue()
|
|
<< " Kind:" << AF.getKind() << ">";
|
|
return OS;
|
|
}
|
|
|
|
}
|
|
|
|
void MCFragment::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<";
|
|
switch (getKind()) {
|
|
case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
|
|
case MCFragment::FT_Data: OS << "MCDataFragment"; break;
|
|
case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
|
|
case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
|
|
case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
|
|
case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
|
|
case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
|
|
case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
|
|
}
|
|
|
|
OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
|
|
<< " Offset:" << Offset << ">";
|
|
|
|
switch (getKind()) {
|
|
case MCFragment::FT_Align: {
|
|
const MCAlignFragment *AF = cast<MCAlignFragment>(this);
|
|
if (AF->hasEmitNops())
|
|
OS << " (emit nops)";
|
|
OS << "\n ";
|
|
OS << " Alignment:" << AF->getAlignment()
|
|
<< " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
|
|
<< " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
|
|
break;
|
|
}
|
|
case MCFragment::FT_Data: {
|
|
const MCDataFragment *DF = cast<MCDataFragment>(this);
|
|
OS << "\n ";
|
|
OS << " Contents:[";
|
|
const SmallVectorImpl<char> &Contents = DF->getContents();
|
|
for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
|
|
if (i) OS << ",";
|
|
OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
|
|
}
|
|
OS << "] (" << Contents.size() << " bytes)";
|
|
|
|
if (!DF->getFixups().empty()) {
|
|
OS << ",\n ";
|
|
OS << " Fixups:[";
|
|
for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
|
|
ie = DF->fixup_end(); it != ie; ++it) {
|
|
if (it != DF->fixup_begin()) OS << ",\n ";
|
|
OS << *it;
|
|
}
|
|
OS << "]";
|
|
}
|
|
break;
|
|
}
|
|
case MCFragment::FT_Fill: {
|
|
const MCFillFragment *FF = cast<MCFillFragment>(this);
|
|
OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
|
|
<< " Size:" << FF->getSize();
|
|
break;
|
|
}
|
|
case MCFragment::FT_Inst: {
|
|
const MCInstFragment *IF = cast<MCInstFragment>(this);
|
|
OS << "\n ";
|
|
OS << " Inst:";
|
|
IF->getInst().dump_pretty(OS);
|
|
break;
|
|
}
|
|
case MCFragment::FT_Org: {
|
|
const MCOrgFragment *OF = cast<MCOrgFragment>(this);
|
|
OS << "\n ";
|
|
OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
|
|
break;
|
|
}
|
|
case MCFragment::FT_Dwarf: {
|
|
const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
|
|
OS << "\n ";
|
|
OS << " AddrDelta:" << OF->getAddrDelta()
|
|
<< " LineDelta:" << OF->getLineDelta();
|
|
break;
|
|
}
|
|
case MCFragment::FT_DwarfFrame: {
|
|
const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
|
|
OS << "\n ";
|
|
OS << " AddrDelta:" << CF->getAddrDelta();
|
|
break;
|
|
}
|
|
case MCFragment::FT_LEB: {
|
|
const MCLEBFragment *LF = cast<MCLEBFragment>(this);
|
|
OS << "\n ";
|
|
OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
|
|
break;
|
|
}
|
|
}
|
|
OS << ">";
|
|
}
|
|
|
|
void MCSectionData::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCSectionData";
|
|
OS << " Alignment:" << getAlignment() << " Fragments:[\n ";
|
|
for (iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
if (it != begin()) OS << ",\n ";
|
|
it->dump();
|
|
}
|
|
OS << "]>";
|
|
}
|
|
|
|
void MCSymbolData::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCSymbolData Symbol:" << getSymbol()
|
|
<< " Fragment:" << getFragment() << " Offset:" << getOffset()
|
|
<< " Flags:" << getFlags() << " Index:" << getIndex();
|
|
if (isCommon())
|
|
OS << " (common, size:" << getCommonSize()
|
|
<< " align: " << getCommonAlignment() << ")";
|
|
if (isExternal())
|
|
OS << " (external)";
|
|
if (isPrivateExtern())
|
|
OS << " (private extern)";
|
|
OS << ">";
|
|
}
|
|
|
|
void MCAssembler::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCAssembler\n";
|
|
OS << " Sections:[\n ";
|
|
for (iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
if (it != begin()) OS << ",\n ";
|
|
it->dump();
|
|
}
|
|
OS << "],\n";
|
|
OS << " Symbols:[";
|
|
|
|
for (symbol_iterator it = symbol_begin(), ie = symbol_end(); it != ie; ++it) {
|
|
if (it != symbol_begin()) OS << ",\n ";
|
|
it->dump();
|
|
}
|
|
OS << "]>\n";
|
|
}
|