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https://github.com/RPCS3/llvm-mirror.git
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74330a6389
llvm-svn: 98952
877 lines
27 KiB
C++
877 lines
27 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/MCExpr.h"
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#include "llvm/MC/MCObjectWriter.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/MachObjectWriter.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/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Target/TargetRegistry.h"
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#include "llvm/Target/TargetAsmBackend.h"
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// FIXME: Gross.
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#include "../Target/X86/X86FixupKinds.h"
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#include <vector>
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using namespace llvm;
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STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
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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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static bool isFixupKindPCRel(unsigned Kind) {
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switch (Kind) {
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default:
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return false;
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case X86::reloc_pcrel_1byte:
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case X86::reloc_pcrel_4byte:
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case X86::reloc_riprel_4byte:
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return true;
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}
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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(FragmentType _Kind, MCSectionData *_Parent)
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: Kind(_Kind),
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Parent(_Parent),
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FileSize(~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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MCFragment::~MCFragment() {
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}
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uint64_t MCFragment::getAddress() const {
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assert(getParent() && "Missing Section!");
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return getParent()->getAddress() + Offset;
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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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Alignment(1),
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Address(~UINT64_C(0)),
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Size(~UINT64_C(0)),
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FileSize(~UINT64_C(0)),
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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), CommonAlign(0), 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, TargetAsmBackend &_Backend,
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raw_ostream &_OS)
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: Context(_Context), Backend(_Backend), OS(_OS), SubsectionsViaSymbols(false)
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{
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}
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MCAssembler::~MCAssembler() {
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}
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static bool isScatteredFixupFullyResolvedSimple(const MCAssembler &Asm,
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const MCAsmFixup &Fixup,
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const MCDataFragment *DF,
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const MCValue Target,
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const MCSection *BaseSection) {
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// The effective fixup address is
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// addr(atom(A)) + offset(A)
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// - addr(atom(B)) - offset(B)
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// - addr(<base symbol>) + <fixup offset from base symbol>
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// and the offsets are not relocatable, so the fixup is fully resolved when
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// addr(atom(A)) - addr(atom(B)) - addr(<base symbol>)) == 0.
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//
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// The simple (Darwin, except on x86_64) way of dealing with this was to
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// assume that any reference to a temporary symbol *must* be a temporary
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// symbol in the same atom, unless the sections differ. Therefore, any PCrel
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// relocation to a temporary symbol (in the same section) is fully
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// resolved. This also works in conjunction with absolutized .set, which
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// requires the compiler to use .set to absolutize the differences between
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// symbols which the compiler knows to be assembly time constants, so we don't
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// need to worry about consider symbol differences fully resolved.
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// Non-relative fixups are only resolved if constant.
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if (!BaseSection)
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return Target.isAbsolute();
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// Otherwise, relative fixups are only resolved if not a difference and the
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// target is a temporary in the same section.
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if (Target.isAbsolute() || Target.getSymB())
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return false;
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const MCSymbol *A = &Target.getSymA()->getSymbol();
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if (!A->isTemporary() || !A->isInSection() ||
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&A->getSection() != BaseSection)
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return false;
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return true;
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}
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static bool isScatteredFixupFullyResolved(const MCAssembler &Asm,
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const MCAsmFixup &Fixup,
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const MCDataFragment *DF,
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const MCValue Target,
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const MCSymbolData *BaseSymbol) {
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// The effective fixup address is
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// addr(atom(A)) + offset(A)
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// - addr(atom(B)) - offset(B)
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// - addr(BaseSymbol) + <fixup offset from base symbol>
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// and the offsets are not relocatable, so the fixup is fully resolved when
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// addr(atom(A)) - addr(atom(B)) - addr(BaseSymbol) == 0.
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//
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// Note that "false" is almost always conservatively correct (it means we emit
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// a relocation which is unnecessary), except when it would force us to emit a
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// relocation which the target cannot encode.
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const MCSymbolData *A_Base = 0, *B_Base = 0;
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if (const MCSymbolRefExpr *A = Target.getSymA()) {
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// Modified symbol references cannot be resolved.
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if (A->getKind() != MCSymbolRefExpr::VK_None)
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return false;
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A_Base = Asm.getAtom(&Asm.getSymbolData(A->getSymbol()));
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if (!A_Base)
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return false;
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}
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if (const MCSymbolRefExpr *B = Target.getSymB()) {
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// Modified symbol references cannot be resolved.
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if (B->getKind() != MCSymbolRefExpr::VK_None)
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return false;
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B_Base = Asm.getAtom(&Asm.getSymbolData(B->getSymbol()));
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if (!B_Base)
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return false;
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}
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// If there is no base, A and B have to be the same atom for this fixup to be
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// fully resolved.
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if (!BaseSymbol)
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return A_Base == B_Base;
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// Otherwise, B must be missing and A must be the base.
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return !B_Base && BaseSymbol == A_Base;
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}
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bool MCAssembler::isSymbolLinkerVisible(const MCSymbolData *SD) const {
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// Non-temporary labels should always be visible to the linker.
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if (!SD->getSymbol().isTemporary())
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return true;
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// Absolute temporary labels are never visible.
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if (!SD->getFragment())
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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(
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SD->getFragment()->getParent()->getSection());
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}
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const MCSymbolData *MCAssembler::getAtomForAddress(const MCSectionData *Section,
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uint64_t Address) const {
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const MCSymbolData *Best = 0;
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for (MCAssembler::const_symbol_iterator it = symbol_begin(),
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ie = symbol_end(); it != ie; ++it) {
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// Ignore non-linker visible symbols.
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if (!isSymbolLinkerVisible(it))
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continue;
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// Ignore symbols not in the same section.
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if (!it->getFragment() || it->getFragment()->getParent() != Section)
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continue;
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// Otherwise, find the closest symbol preceding this address (ties are
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// resolved in favor of the last defined symbol).
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if (it->getAddress() <= Address &&
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(!Best || it->getAddress() >= Best->getAddress()))
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Best = it;
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}
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return Best;
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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))
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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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// Otherwise, search by address.
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return getAtomForAddress(SD->getFragment()->getParent(), SD->getAddress());
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}
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bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout, MCAsmFixup &Fixup,
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MCDataFragment *DF,
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MCValue &Target, uint64_t &Value) const {
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if (!Fixup.Value->EvaluateAsRelocatable(Target, &Layout))
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llvm_report_error("expected relocatable expression");
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// FIXME: How do non-scattered symbols work in ELF? I presume the linker
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// doesn't support small relocations, but then under what criteria does the
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// assembler allow symbol differences?
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Value = Target.getConstant();
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bool IsResolved = true, IsPCRel = isFixupKindPCRel(Fixup.Kind);
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if (const MCSymbolRefExpr *A = Target.getSymA()) {
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if (A->getSymbol().isDefined())
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Value += getSymbolData(A->getSymbol()).getAddress();
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else
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IsResolved = false;
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}
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if (const MCSymbolRefExpr *B = Target.getSymB()) {
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if (B->getSymbol().isDefined())
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Value -= getSymbolData(B->getSymbol()).getAddress();
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else
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IsResolved = false;
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}
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// If we are using scattered symbols, determine whether this value is actually
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// resolved; scattering may cause atoms to move.
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if (IsResolved && getBackend().hasScatteredSymbols()) {
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if (getBackend().hasReliableSymbolDifference()) {
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// If this is a PCrel relocation, find the base atom (identified by its
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// symbol) that the fixup value is relative to.
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const MCSymbolData *BaseSymbol = 0;
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if (IsPCRel) {
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BaseSymbol = getAtomForAddress(
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DF->getParent(), DF->getAddress() + Fixup.Offset);
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if (!BaseSymbol)
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IsResolved = false;
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}
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if (IsResolved)
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IsResolved = isScatteredFixupFullyResolved(*this, Fixup, DF, Target,
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BaseSymbol);
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} else {
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const MCSection *BaseSection = 0;
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if (IsPCRel)
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BaseSection = &DF->getParent()->getSection();
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IsResolved = isScatteredFixupFullyResolvedSimple(*this, Fixup, DF, Target,
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BaseSection);
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}
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}
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if (IsPCRel)
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Value -= DF->getAddress() + Fixup.Offset;
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return IsResolved;
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}
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void MCAssembler::LayoutSection(MCSectionData &SD) {
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MCAsmLayout Layout(*this);
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uint64_t Address = SD.getAddress();
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for (MCSectionData::iterator it = SD.begin(), ie = SD.end(); it != ie; ++it) {
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MCFragment &F = *it;
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F.setOffset(Address - SD.getAddress());
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// Evaluate fragment size.
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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 Size = OffsetToAlignment(Address, AF.getAlignment());
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if (Size > AF.getMaxBytesToEmit())
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AF.setFileSize(0);
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else
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AF.setFileSize(Size);
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break;
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}
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case MCFragment::FT_Data:
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case MCFragment::FT_Fill:
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F.setFileSize(F.getMaxFileSize());
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break;
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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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llvm_report_error("expected assembly-time absolute expression");
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// FIXME: We need a way to communicate this error.
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int64_t Offset = TargetLocation - F.getOffset();
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if (Offset < 0)
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llvm_report_error("invalid .org offset '" + Twine(TargetLocation) +
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"' (at offset '" + Twine(F.getOffset()) + "'");
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F.setFileSize(Offset);
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break;
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}
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case MCFragment::FT_ZeroFill: {
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MCZeroFillFragment &ZFF = cast<MCZeroFillFragment>(F);
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// Align the fragment offset; it is safe to adjust the offset freely since
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// this is only in virtual sections.
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Address = RoundUpToAlignment(Address, ZFF.getAlignment());
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F.setOffset(Address - SD.getAddress());
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// FIXME: This is misnamed.
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F.setFileSize(ZFF.getSize());
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break;
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}
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}
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Address += F.getFileSize();
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}
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// Set the section sizes.
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SD.setSize(Address - SD.getAddress());
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if (getBackend().isVirtualSection(SD.getSection()))
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SD.setFileSize(0);
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else
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SD.setFileSize(Address - SD.getAddress());
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}
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/// WriteNopData - Write optimal nops to the output file for the \arg Count
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/// bytes. This returns the number of bytes written. It may return 0 if
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/// the \arg Count is more than the maximum optimal nops.
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///
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/// FIXME this is X86 32-bit specific and should move to a better place.
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static uint64_t WriteNopData(uint64_t Count, MCObjectWriter *OW) {
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static const uint8_t Nops[16][16] = {
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// nop
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{0x90},
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// xchg %ax,%ax
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{0x66, 0x90},
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// nopl (%[re]ax)
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{0x0f, 0x1f, 0x00},
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// nopl 0(%[re]ax)
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{0x0f, 0x1f, 0x40, 0x00},
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// nopl 0(%[re]ax,%[re]ax,1)
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{0x0f, 0x1f, 0x44, 0x00, 0x00},
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// nopw 0(%[re]ax,%[re]ax,1)
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{0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
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// nopl 0L(%[re]ax)
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{0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
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// nopl 0L(%[re]ax,%[re]ax,1)
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{0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
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// nopw 0L(%[re]ax,%[re]ax,1)
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{0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
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// nopw %cs:0L(%[re]ax,%[re]ax,1)
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{0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
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// nopl 0(%[re]ax,%[re]ax,1)
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// nopw 0(%[re]ax,%[re]ax,1)
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{0x0f, 0x1f, 0x44, 0x00, 0x00,
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0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
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// nopw 0(%[re]ax,%[re]ax,1)
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// nopw 0(%[re]ax,%[re]ax,1)
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{0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
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0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
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// nopw 0(%[re]ax,%[re]ax,1)
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// nopl 0L(%[re]ax) */
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{0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
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0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
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// nopl 0L(%[re]ax)
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// nopl 0L(%[re]ax)
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{0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
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0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
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// nopl 0L(%[re]ax)
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// nopl 0L(%[re]ax,%[re]ax,1)
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{0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
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0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00}
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};
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if (Count > 15)
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return 0;
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for (uint64_t i = 0; i < Count; i++)
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OW->Write8(uint8_t(Nops[Count - 1][i]));
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return Count;
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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 MCFragment &F, MCObjectWriter *OW) {
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uint64_t Start = OW->getStream().tell();
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(void) Start;
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++EmittedFragments;
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// FIXME: Embed in fragments instead?
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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 = AF.getFileSize() / AF.getValueSize();
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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() != AF.getFileSize())
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llvm_report_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(AF.getFileSize()) + "'");
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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 (AF.getEmitNops()) {
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uint64_t NopByteCount = WriteNopData(Count, OW);
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Count -= NopByteCount;
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}
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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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|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_Data: {
|
|
OW->WriteBytes(cast<MCDataFragment>(F).getContents().str());
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_Fill: {
|
|
MCFillFragment &FF = cast<MCFillFragment>(F);
|
|
for (uint64_t i = 0, e = FF.getCount(); i != e; ++i) {
|
|
switch (FF.getValueSize()) {
|
|
default:
|
|
assert(0 && "Invalid size!");
|
|
case 1: OW->Write8 (uint8_t (FF.getValue())); break;
|
|
case 2: OW->Write16(uint16_t(FF.getValue())); break;
|
|
case 4: OW->Write32(uint32_t(FF.getValue())); break;
|
|
case 8: OW->Write64(uint64_t(FF.getValue())); break;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_Org: {
|
|
MCOrgFragment &OF = cast<MCOrgFragment>(F);
|
|
|
|
for (uint64_t i = 0, e = OF.getFileSize(); i != e; ++i)
|
|
OW->Write8(uint8_t(OF.getValue()));
|
|
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_ZeroFill: {
|
|
assert(0 && "Invalid zero fill fragment in concrete section!");
|
|
break;
|
|
}
|
|
}
|
|
|
|
assert(OW->getStream().tell() - Start == F.getFileSize());
|
|
}
|
|
|
|
void MCAssembler::WriteSectionData(const MCSectionData *SD,
|
|
MCObjectWriter *OW) const {
|
|
// Ignore virtual sections.
|
|
if (getBackend().isVirtualSection(SD->getSection())) {
|
|
assert(SD->getFileSize() == 0);
|
|
return;
|
|
}
|
|
|
|
uint64_t Start = OW->getStream().tell();
|
|
(void) Start;
|
|
|
|
for (MCSectionData::const_iterator it = SD->begin(),
|
|
ie = SD->end(); it != ie; ++it)
|
|
WriteFragmentData(*it, OW);
|
|
|
|
// Add section padding.
|
|
assert(SD->getFileSize() >= SD->getSize() && "Invalid section sizes!");
|
|
OW->WriteZeros(SD->getFileSize() - SD->getSize());
|
|
|
|
assert(OW->getStream().tell() - Start == SD->getFileSize());
|
|
}
|
|
|
|
void MCAssembler::Finish() {
|
|
DEBUG_WITH_TYPE("mc-dump", {
|
|
llvm::errs() << "assembler backend - pre-layout\n--\n";
|
|
dump(); });
|
|
|
|
// Layout until everything fits.
|
|
while (LayoutOnce())
|
|
continue;
|
|
|
|
DEBUG_WITH_TYPE("mc-dump", {
|
|
llvm::errs() << "assembler backend - post-layout\n--\n";
|
|
dump(); });
|
|
|
|
// FIXME: Factor out MCObjectWriter.
|
|
bool Is64Bit = StringRef(getBackend().getTarget().getName()) == "x86-64";
|
|
MachObjectWriter MOW(OS, Is64Bit);
|
|
|
|
// Allow the object writer a chance to perform post-layout binding (for
|
|
// example, to set the index fields in the symbol data).
|
|
MOW.ExecutePostLayoutBinding(*this);
|
|
|
|
// Evaluate and apply the fixups, generating relocation entries as necessary.
|
|
//
|
|
// FIXME: Share layout object.
|
|
MCAsmLayout Layout(*this);
|
|
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.
|
|
MOW.RecordRelocation(*this, *DF, Fixup, Target, FixedValue);
|
|
}
|
|
|
|
getBackend().ApplyFixup(Fixup, *DF, FixedValue);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Write the object file.
|
|
MOW.WriteObject(*this);
|
|
|
|
OS.flush();
|
|
}
|
|
|
|
bool MCAssembler::FixupNeedsRelaxation(MCAsmFixup &Fixup, MCDataFragment *DF) {
|
|
// FIXME: Share layout object.
|
|
MCAsmLayout Layout(*this);
|
|
|
|
// Currently we only need to relax X86::reloc_pcrel_1byte.
|
|
if (unsigned(Fixup.Kind) != X86::reloc_pcrel_1byte)
|
|
return false;
|
|
|
|
// If we cannot resolve the fixup value, it requires relaxation.
|
|
MCValue Target;
|
|
uint64_t Value;
|
|
if (!EvaluateFixup(Layout, Fixup, DF, Target, Value))
|
|
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::LayoutOnce() {
|
|
// Layout the concrete sections and fragments.
|
|
uint64_t Address = 0;
|
|
MCSectionData *Prev = 0;
|
|
for (iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
MCSectionData &SD = *it;
|
|
|
|
// Skip virtual sections.
|
|
if (getBackend().isVirtualSection(SD.getSection()))
|
|
continue;
|
|
|
|
// Align this section if necessary by adding padding bytes to the previous
|
|
// section.
|
|
if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment())) {
|
|
assert(Prev && "Missing prev section!");
|
|
Prev->setFileSize(Prev->getFileSize() + Pad);
|
|
Address += Pad;
|
|
}
|
|
|
|
// Layout the section fragments and its size.
|
|
SD.setAddress(Address);
|
|
LayoutSection(SD);
|
|
Address += SD.getFileSize();
|
|
|
|
Prev = &SD;
|
|
}
|
|
|
|
// Layout the virtual sections.
|
|
for (iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
MCSectionData &SD = *it;
|
|
|
|
if (!getBackend().isVirtualSection(SD.getSection()))
|
|
continue;
|
|
|
|
// Align this section if necessary by adding padding bytes to the previous
|
|
// section.
|
|
if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment()))
|
|
Address += Pad;
|
|
|
|
SD.setAddress(Address);
|
|
LayoutSection(SD);
|
|
Address += SD.getSize();
|
|
}
|
|
|
|
// Scan the fixups in order and relax any that don't fit.
|
|
for (iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
MCSectionData &SD = *it;
|
|
|
|
for (MCSectionData::iterator it2 = SD.begin(),
|
|
ie2 = SD.end(); it2 != ie2; ++it2) {
|
|
MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
|
|
if (!DF)
|
|
continue;
|
|
|
|
for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
|
|
ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
|
|
MCAsmFixup &Fixup = *it3;
|
|
|
|
// Check whether we need to relax this fixup.
|
|
if (!FixupNeedsRelaxation(Fixup, DF))
|
|
continue;
|
|
|
|
// Relax the instruction.
|
|
//
|
|
// FIXME: This is a huge temporary hack which just looks for x86
|
|
// branches; the only thing we need to relax on x86 is
|
|
// 'X86::reloc_pcrel_1byte'. Once we have MCInst fragments, this will be
|
|
// replaced by a TargetAsmBackend hook (most likely tblgen'd) to relax
|
|
// an individual MCInst.
|
|
SmallVectorImpl<char> &C = DF->getContents();
|
|
uint64_t PrevOffset = Fixup.Offset;
|
|
unsigned Amt = 0;
|
|
|
|
// jcc instructions
|
|
if (unsigned(C[Fixup.Offset-1]) >= 0x70 &&
|
|
unsigned(C[Fixup.Offset-1]) <= 0x7f) {
|
|
C[Fixup.Offset] = C[Fixup.Offset-1] + 0x10;
|
|
C[Fixup.Offset-1] = char(0x0f);
|
|
++Fixup.Offset;
|
|
Amt = 4;
|
|
|
|
// jmp rel8
|
|
} else if (C[Fixup.Offset-1] == char(0xeb)) {
|
|
C[Fixup.Offset-1] = char(0xe9);
|
|
Amt = 3;
|
|
|
|
} else
|
|
llvm_unreachable("unknown 1 byte pcrel instruction!");
|
|
|
|
Fixup.Value = MCBinaryExpr::Create(
|
|
MCBinaryExpr::Sub, Fixup.Value,
|
|
MCConstantExpr::Create(3, getContext()),
|
|
getContext());
|
|
C.insert(C.begin() + Fixup.Offset, Amt, char(0));
|
|
Fixup.Kind = MCFixupKind(X86::reloc_pcrel_4byte);
|
|
|
|
// Update the remaining fixups, which have slid.
|
|
//
|
|
// FIXME: This is bad for performance, but will be eliminated by the
|
|
// move to MCInst specific fragments.
|
|
++it3;
|
|
for (; it3 != ie3; ++it3)
|
|
it3->Offset += Amt;
|
|
|
|
// Update all the symbols for this fragment, which may have slid.
|
|
//
|
|
// FIXME: This is really really bad for performance, but will be
|
|
// eliminated by the move to MCInst specific fragments.
|
|
for (MCAssembler::symbol_iterator it = symbol_begin(),
|
|
ie = symbol_end(); it != ie; ++it) {
|
|
MCSymbolData &SD = *it;
|
|
|
|
if (it->getFragment() != DF)
|
|
continue;
|
|
|
|
if (SD.getOffset() > PrevOffset)
|
|
SD.setOffset(SD.getOffset() + Amt);
|
|
}
|
|
|
|
// Restart layout.
|
|
//
|
|
// FIXME: This is O(N^2), but will be eliminated once we have a smart
|
|
// MCAsmLayout object.
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
// Debugging methods
|
|
|
|
namespace llvm {
|
|
|
|
raw_ostream &operator<<(raw_ostream &OS, const MCAsmFixup &AF) {
|
|
OS << "<MCAsmFixup" << " Offset:" << AF.Offset << " Value:" << *AF.Value
|
|
<< " Kind:" << AF.Kind << ">";
|
|
return OS;
|
|
}
|
|
|
|
}
|
|
|
|
void MCFragment::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCFragment " << (void*) this << " Offset:" << Offset
|
|
<< " FileSize:" << FileSize;
|
|
|
|
OS << ">";
|
|
}
|
|
|
|
void MCAlignFragment::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCAlignFragment ";
|
|
this->MCFragment::dump();
|
|
OS << "\n ";
|
|
OS << " Alignment:" << getAlignment()
|
|
<< " Value:" << getValue() << " ValueSize:" << getValueSize()
|
|
<< " MaxBytesToEmit:" << getMaxBytesToEmit() << ">";
|
|
}
|
|
|
|
void MCDataFragment::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCDataFragment ";
|
|
this->MCFragment::dump();
|
|
OS << "\n ";
|
|
OS << " Contents:[";
|
|
for (unsigned i = 0, e = getContents().size(); i != e; ++i) {
|
|
if (i) OS << ",";
|
|
OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
|
|
}
|
|
OS << "] (" << getContents().size() << " bytes)";
|
|
|
|
if (!getFixups().empty()) {
|
|
OS << ",\n ";
|
|
OS << " Fixups:[";
|
|
for (fixup_iterator it = fixup_begin(), ie = fixup_end(); it != ie; ++it) {
|
|
if (it != fixup_begin()) OS << ",\n ";
|
|
OS << *it;
|
|
}
|
|
OS << "]";
|
|
}
|
|
|
|
OS << ">";
|
|
}
|
|
|
|
void MCFillFragment::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCFillFragment ";
|
|
this->MCFragment::dump();
|
|
OS << "\n ";
|
|
OS << " Value:" << getValue() << " ValueSize:" << getValueSize()
|
|
<< " Count:" << getCount() << ">";
|
|
}
|
|
|
|
void MCOrgFragment::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCOrgFragment ";
|
|
this->MCFragment::dump();
|
|
OS << "\n ";
|
|
OS << " Offset:" << getOffset() << " Value:" << getValue() << ">";
|
|
}
|
|
|
|
void MCZeroFillFragment::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCZeroFillFragment ";
|
|
this->MCFragment::dump();
|
|
OS << "\n ";
|
|
OS << " Size:" << getSize() << " Alignment:" << getAlignment() << ">";
|
|
}
|
|
|
|
void MCSectionData::dump() {
|
|
raw_ostream &OS = llvm::errs();
|
|
|
|
OS << "<MCSectionData";
|
|
OS << " Alignment:" << getAlignment() << " Address:" << Address
|
|
<< " Size:" << Size << " FileSize:" << FileSize
|
|
<< " 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";
|
|
}
|