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llvm-mirror/lib/MC/MCFragment.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

468 lines
15 KiB
C++

//===- lib/MC/MCFragment.cpp - Assembler Fragment Implementation ----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCFragment.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdint>
#include <utility>
using namespace llvm;
MCAsmLayout::MCAsmLayout(MCAssembler &Asm) : Assembler(Asm) {
// 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-variable 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(
Expr->getLoc(), "expression could not be evaluated");
return nullptr;
}
const MCSymbolRefExpr *RefB = Value.getSymB();
if (RefB) {
Assembler.getContext().reportError(
Expr->getLoc(), 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()) {
Asm.getContext().reportError(Expr->getLoc(),
"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 MCEncodedFragment *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_alloc_traits<MCFragment>::deleteNode(MCFragment *V) { V->destroy(); }
MCFragment::~MCFragment() = default;
MCFragment::MCFragment(FragmentType Kind, bool HasInstructions,
MCSection *Parent)
: Kind(Kind), HasInstructions(HasInstructions), LayoutOrder(0),
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_Padding:
delete cast<MCPaddingFragment>(this);
return;
case FT_SymbolId:
delete cast<MCSymbolIdFragment>(this);
return;
case FT_CVInlineLines:
delete cast<MCCVInlineLineTableFragment>(this);
return;
case FT_CVDefRange:
delete cast<MCCVDefRangeFragment>(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;
}
} // end namespace llvm
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void MCFragment::dump() const {
raw_ostream &OS = 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_Padding: OS << "MCPaddingFragment"; break;
case MCFragment::FT_SymbolId: OS << "MCSymbolIdFragment"; break;
case MCFragment::FT_CVInlineLines: OS << "MCCVInlineLineTableFragment"; break;
case MCFragment::FT_CVDefRange: OS << "MCCVDefRangeTableFragment"; break;
case MCFragment::FT_Dummy: OS << "MCDummyFragment"; break;
}
OS << "<MCFragment " << (const void *)this << " LayoutOrder:" << LayoutOrder
<< " Offset:" << Offset << " HasInstructions:" << hasInstructions();
if (const MCEncodedFragment *EF = dyn_cast<MCEncodedFragment>(this))
OS << " BundlePadding:" << static_cast<unsigned>(EF->getBundlePadding());
OS << ">";
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:" << static_cast<unsigned>(FF->getValue())
<< " ValueSize:" << static_cast<unsigned>(FF->getValueSize())
<< " NumValues:" << FF->getNumValues();
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:" << static_cast<unsigned>(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_Padding: {
const MCPaddingFragment *F = cast<MCPaddingFragment>(this);
OS << "\n ";
OS << " PaddingPoliciesMask:" << F->getPaddingPoliciesMask()
<< " IsInsertionPoint:" << F->isInsertionPoint()
<< " Size:" << F->getSize();
OS << "\n ";
OS << " Inst:";
F->getInst().dump_pretty(OS);
OS << " InstSize:" << F->getInstSize();
OS << "\n ";
break;
}
case MCFragment::FT_SymbolId: {
const MCSymbolIdFragment *F = cast<MCSymbolIdFragment>(this);
OS << "\n ";
OS << " Sym:" << F->getSymbol();
break;
}
case MCFragment::FT_CVInlineLines: {
const auto *F = cast<MCCVInlineLineTableFragment>(this);
OS << "\n ";
OS << " Sym:" << *F->getFnStartSym();
break;
}
case MCFragment::FT_CVDefRange: {
const auto *F = cast<MCCVDefRangeFragment>(this);
OS << "\n ";
for (std::pair<const MCSymbol *, const MCSymbol *> RangeStartEnd :
F->getRanges()) {
OS << " RangeStart:" << RangeStartEnd.first;
OS << " RangeEnd:" << RangeStartEnd.second;
}
break;
}
case MCFragment::FT_Dummy:
break;
}
OS << ">";
}
#endif