maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/lib/MC/MCFragment.cpp

459 lines
14 KiB
C++
Raw Blame History

//===- lib/MC/MCFragment.cpp - Assembler Fragment Implementation ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCFragment.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include <tuple>
using namespace llvm;
MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
: Assembler(Asm), LastValidFragment()
{
// Compute the section layout order. Virtual sections must go last.
for (MCSection &Sec : Asm)
if (!Sec.isVirtualSection())
SectionOrder.push_back(&Sec);
for (MCSection &Sec : Asm)
if (Sec.isVirtualSection())
SectionOrder.push_back(&Sec);
}
bool MCAsmLayout::isFragmentValid(const MCFragment *F) const {
const MCSection *Sec = F->getParent();
const MCFragment *LastValid = LastValidFragment.lookup(Sec);
if (!LastValid)
return false;
assert(LastValid->getParent() == Sec);
return F->getLayoutOrder() <= LastValid->getLayoutOrder();
}
void MCAsmLayout::invalidateFragmentsFrom(MCFragment *F) {
// If this fragment wasn't already valid, we don't need to do anything.
if (!isFragmentValid(F))
return;
// Otherwise, reset the last valid fragment to the previous fragment
// (if this is the first fragment, it will be NULL).
LastValidFragment[F->getParent()] = F->getPrevNode();
}
void MCAsmLayout::ensureValid(const MCFragment *F) const {
MCSection *Sec = F->getParent();
MCSection::iterator I;
if (MCFragment *Cur = LastValidFragment[Sec])
I = ++MCSection::iterator(Cur);
else
I = Sec->begin();
// Advance the layout position until the fragment is valid.
while (!isFragmentValid(F)) {
assert(I != Sec->end() && "Layout bookkeeping error");
const_cast<MCAsmLayout *>(this)->layoutFragment(&*I);
++I;
}
}
uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
ensureValid(F);
assert(F->Offset != ~UINT64_C(0) && "Address not set!");
return F->Offset;
}
// Simple getSymbolOffset helper for the non-varibale case.
static bool getLabelOffset(const MCAsmLayout &Layout, const MCSymbol &S,
bool ReportError, uint64_t &Val) {
if (!S.getFragment()) {
if (ReportError)
report_fatal_error("unable to evaluate offset to undefined symbol '" +
S.getName() + "'");
return false;
}
Val = Layout.getFragmentOffset(S.getFragment()) + S.getOffset();
return true;
}
static bool getSymbolOffsetImpl(const MCAsmLayout &Layout, const MCSymbol &S,
bool ReportError, uint64_t &Val) {
if (!S.isVariable())
return getLabelOffset(Layout, S, ReportError, Val);
// If SD is a variable, evaluate it.
MCValue Target;
if (!S.getVariableValue()->evaluateAsValue(Target, Layout))
report_fatal_error("unable to evaluate offset for variable '" +
S.getName() + "'");
uint64_t Offset = Target.getConstant();
const MCSymbolRefExpr *A = Target.getSymA();
if (A) {
uint64_t ValA;
if (!getLabelOffset(Layout, A->getSymbol(), ReportError, ValA))
return false;
Offset += ValA;
}
const MCSymbolRefExpr *B = Target.getSymB();
if (B) {
uint64_t ValB;
if (!getLabelOffset(Layout, B->getSymbol(), ReportError, ValB))
return false;
Offset -= ValB;
}
Val = Offset;
return true;
}
bool MCAsmLayout::getSymbolOffset(const MCSymbol &S, uint64_t &Val) const {
return getSymbolOffsetImpl(*this, S, false, Val);
}
uint64_t MCAsmLayout::getSymbolOffset(const MCSymbol &S) const {
uint64_t Val;
getSymbolOffsetImpl(*this, S, true, Val);
return Val;
}
const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
if (!Symbol.isVariable())
return &Symbol;
const MCExpr *Expr = Symbol.getVariableValue();
MCValue Value;
if (!Expr->evaluateAsValue(Value, *this)) {
Assembler.getContext().reportError(
SMLoc(), "expression could not be evaluated");
return nullptr;
}
const MCSymbolRefExpr *RefB = Value.getSymB();
if (RefB) {
Assembler.getContext().reportError(
SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
"' could not be evaluated in a subtraction expression");
return nullptr;
}
const MCSymbolRefExpr *A = Value.getSymA();
if (!A)
return nullptr;
const MCSymbol &ASym = A->getSymbol();
const MCAssembler &Asm = getAssembler();
if (ASym.isCommon()) {
// FIXME: we should probably add a SMLoc to MCExpr.
Asm.getContext().reportError(SMLoc(),
"Common symbol '" + ASym.getName() +
"' cannot be used in assignment expr");
return nullptr;
}
return &ASym;
}
uint64_t MCAsmLayout::getSectionAddressSize(const MCSection *Sec) const {
// The size is the last fragment's end offset.
const MCFragment &F = Sec->getFragmentList().back();
return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
}
uint64_t MCAsmLayout::getSectionFileSize(const MCSection *Sec) const {
// Virtual sections have no file size.
if (Sec->isVirtualSection())
return 0;
// Otherwise, the file size is the same as the address space size.
return getSectionAddressSize(Sec);
}
uint64_t llvm::computeBundlePadding(const MCAssembler &Assembler,
const MCFragment *F,
uint64_t FOffset, uint64_t FSize) {
uint64_t BundleSize = Assembler.getBundleAlignSize();
assert(BundleSize > 0 &&
"computeBundlePadding should only be called if bundling is enabled");
uint64_t BundleMask = BundleSize - 1;
uint64_t OffsetInBundle = FOffset & BundleMask;
uint64_t EndOfFragment = OffsetInBundle + FSize;
// There are two kinds of bundling restrictions:
//
// 1) For alignToBundleEnd(), add padding to ensure that the fragment will
// *end* on a bundle boundary.
// 2) Otherwise, check if the fragment would cross a bundle boundary. If it
// would, add padding until the end of the bundle so that the fragment
// will start in a new one.
if (F->alignToBundleEnd()) {
// Three possibilities here:
//
// A) The fragment just happens to end at a bundle boundary, so we're good.
// B) The fragment ends before the current bundle boundary: pad it just
// enough to reach the boundary.
// C) The fragment ends after the current bundle boundary: pad it until it
// reaches the end of the next bundle boundary.
//
// Note: this code could be made shorter with some modulo trickery, but it's
// intentionally kept in its more explicit form for simplicity.
if (EndOfFragment == BundleSize)
return 0;
else if (EndOfFragment < BundleSize)
return BundleSize - EndOfFragment;
else { // EndOfFragment > BundleSize
return 2 * BundleSize - EndOfFragment;
}
} else if (OffsetInBundle > 0 && EndOfFragment > BundleSize)
return BundleSize - OffsetInBundle;
else
return 0;
}
/* *** */
void ilist_node_traits<MCFragment>::deleteNode(MCFragment *V) {
V->destroy();
}
MCFragment::MCFragment() : Kind(FragmentType(~0)), HasInstructions(false),
AlignToBundleEnd(false), BundlePadding(0) {
}
MCFragment::~MCFragment() { }
MCFragment::MCFragment(FragmentType Kind, bool HasInstructions,
uint8_t BundlePadding, MCSection *Parent)
: Kind(Kind), HasInstructions(HasInstructions), AlignToBundleEnd(false),
BundlePadding(BundlePadding), Parent(Parent), Atom(nullptr),
Offset(~UINT64_C(0)) {
if (Parent && !isDummy())
Parent->getFragmentList().push_back(this);
}
void MCFragment::destroy() {
// First check if we are the sentinal.
if (Kind == FragmentType(~0)) {
delete this;
return;
}
switch (Kind) {
case FT_Align:
delete cast<MCAlignFragment>(this);
return;
case FT_Data:
delete cast<MCDataFragment>(this);
return;
case FT_CompactEncodedInst:
delete cast<MCCompactEncodedInstFragment>(this);
return;
case FT_Fill:
delete cast<MCFillFragment>(this);
return;
case FT_Relaxable:
delete cast<MCRelaxableFragment>(this);
return;
case FT_Org:
delete cast<MCOrgFragment>(this);
return;
case FT_Dwarf:
delete cast<MCDwarfLineAddrFragment>(this);
return;
case FT_DwarfFrame:
delete cast<MCDwarfCallFrameFragment>(this);
return;
case FT_LEB:
delete cast<MCLEBFragment>(this);
return;
case FT_SafeSEH:
delete cast<MCSafeSEHFragment>(this);
return;
case FT_Dummy:
delete cast<MCDummyFragment>(this);
return;
}
}
/* *** */
// 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;
}
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
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_CompactEncodedInst:
OS << "MCCompactEncodedInstFragment"; break;
case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
case MCFragment::FT_Relaxable: OS << "MCRelaxableFragment"; break;
case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
case MCFragment::FT_SafeSEH: OS << "MCSafeSEHFragment"; break;
case MCFragment::FT_Dummy:
OS << "MCDummyFragment";
break;
}
OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
<< " Offset:" << Offset
<< " HasInstructions:" << hasInstructions()
<< " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
switch (getKind()) {
case MCFragment::FT_Align: {
const MCAlignFragment *AF = cast<MCAlignFragment>(this);
if (AF->hasEmitNops())
OS << " (emit nops)";
OS << "\n ";
OS << " Alignment:" << AF->getAlignment()
<< " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
<< " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
break;
}
case MCFragment::FT_Data: {
const MCDataFragment *DF = cast<MCDataFragment>(this);
OS << "\n ";
OS << " Contents:[";
const SmallVectorImpl<char> &Contents = DF->getContents();
for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
if (i) OS << ",";
OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
}
OS << "] (" << Contents.size() << " bytes)";
if (DF->fixup_begin() != DF->fixup_end()) {
OS << ",\n ";
OS << " Fixups:[";
for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
ie = DF->fixup_end(); it != ie; ++it) {
if (it != DF->fixup_begin()) OS << ",\n ";
OS << *it;
}
OS << "]";
}
break;
}
case MCFragment::FT_CompactEncodedInst: {
const MCCompactEncodedInstFragment *CEIF =
cast<MCCompactEncodedInstFragment>(this);
OS << "\n ";
OS << " Contents:[";
const SmallVectorImpl<char> &Contents = CEIF->getContents();
for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
if (i) OS << ",";
OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
}
OS << "] (" << Contents.size() << " bytes)";
break;
}
case MCFragment::FT_Fill: {
const MCFillFragment *FF = cast<MCFillFragment>(this);
OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
<< " Size:" << FF->getSize();
break;
}
case MCFragment::FT_Relaxable: {
const MCRelaxableFragment *F = cast<MCRelaxableFragment>(this);
OS << "\n ";
OS << " Inst:";
F->getInst().dump_pretty(OS);
break;
}
case MCFragment::FT_Org: {
const MCOrgFragment *OF = cast<MCOrgFragment>(this);
OS << "\n ";
OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
break;
}
case MCFragment::FT_Dwarf: {
const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
OS << "\n ";
OS << " AddrDelta:" << OF->getAddrDelta()
<< " LineDelta:" << OF->getLineDelta();
break;
}
case MCFragment::FT_DwarfFrame: {
const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
OS << "\n ";
OS << " AddrDelta:" << CF->getAddrDelta();
break;
}
case MCFragment::FT_LEB: {
const MCLEBFragment *LF = cast<MCLEBFragment>(this);
OS << "\n ";
OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
break;
}
case MCFragment::FT_SafeSEH: {
const MCSafeSEHFragment *F = cast<MCSafeSEHFragment>(this);
OS << "\n ";
OS << " Sym:" << F->getSymbol();
break;
}
case MCFragment::FT_Dummy:
break;
}
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 ";
OS << "(";
it->dump();
OS << ", Index:" << it->getIndex() << ", ";
OS << ")";
}
OS << "]>\n";
}
#endif
Reference in New Issue View Git Blame Copy Permalink