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//===-- lib/MC/MCObjectSymbolizer.cpp -------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCObjectSymbolizer.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCRelocationInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/ELF.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
using namespace object;
//===- MCMachObjectSymbolizer ---------------------------------------------===//
namespace {
class MCMachObjectSymbolizer : public MCObjectSymbolizer {
public:
MCMachObjectSymbolizer(MCContext &Ctx, OwningPtr<MCRelocationInfo> &RelInfo,
const object::MachOObjectFile *MachOOF)
: MCObjectSymbolizer(Ctx, RelInfo, MachOOF)
{}
void tryAddingPcLoadReferenceComment(raw_ostream &cStream,
int64_t Value, uint64_t Address) {
AddrToRelocMap::iterator RI = AddrToReloc.find(Address);
if (RI != AddrToReloc.end()) {
const MCExpr *RelExpr = RelInfo->createExprForRelocation(RI->second);
if (!RelExpr || RelExpr->EvaluateAsAbsolute(Value) == false)
return;
}
uint64_t Addr = Value;
SortedSectionList::const_iterator SI = findSectionContaining(Addr);
if (SI != SortedSections.end()) {
const SectionRef &S = *SI;
StringRef Name; S.getName(Name);
uint64_t SAddr; S.getAddress(SAddr);
if (Name == "__cstring") {
StringRef Contents;
S.getContents(Contents);
Contents = Contents.substr(Addr - SAddr);
cStream << " ## literal pool for: "
<< Contents.substr(0, Contents.find_first_of(0));
}
}
}
};
} // End unnamed namespace
//===- MCObjectSymbolizer -------------------------------------------------===//
MCObjectSymbolizer::MCObjectSymbolizer(MCContext &Ctx,
OwningPtr<MCRelocationInfo> &RelInfo,
const ObjectFile *Obj)
: MCSymbolizer(Ctx, RelInfo), Obj(Obj), SortedSections(), AddrToReloc() {
error_code ec;
for (section_iterator SI = Obj->begin_sections(),
SE = Obj->end_sections();
SI != SE;
SI.increment(ec)) {
if (ec) break;
section_iterator RelSecI = SI->getRelocatedSection();
if (RelSecI == Obj->end_sections())
continue;
uint64_t StartAddr; RelSecI->getAddress(StartAddr);
uint64_t Size; RelSecI->getSize(Size);
bool RequiredForExec; RelSecI->isRequiredForExecution(RequiredForExec);
if (RequiredForExec == false || Size == 0)
continue;
insertSection(*SI);
for (relocation_iterator RI = SI->begin_relocations(),
RE = SI->end_relocations();
RI != RE;
RI.increment(ec)) {
if (ec) break;
// FIXME: libObject is inconsistent regarding error handling. The
// overwhelming majority of methods always return object_error::success,
// and assert for simple errors.. Here, ELFObjectFile::getRelocationOffset
// asserts when the file type isn't ET_REL.
// This workaround handles x86-64 elf, the only one that has a relocinfo.
uint64_t Offset;
if (Obj->isELF()) {
const ELF64LEObjectFile *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj);
if (ELFObj == 0)
break;
if (ELFObj->getElfHeader()->e_type == ELF::ET_REL) {
RI->getOffset(Offset);
Offset += StartAddr;
} else {
RI->getAddress(Offset);
}
} else {
RI->getOffset(Offset);
Offset += StartAddr;
}
// At a specific address, only keep the first relocation.
if (AddrToReloc.find(Offset) == AddrToReloc.end())
AddrToReloc[Offset] = *RI;
}
}
}
bool MCObjectSymbolizer::
tryAddingSymbolicOperand(MCInst &MI, raw_ostream &cStream,
int64_t Value, uint64_t Address, bool IsBranch,
uint64_t Offset, uint64_t InstSize) {
AddrToRelocMap::iterator RI = AddrToReloc.find(Address + Offset);
if (RI != AddrToReloc.end()) {
if (const MCExpr *RelExpr = RelInfo->createExprForRelocation(RI->second)) {
MI.addOperand(MCOperand::CreateExpr(RelExpr));
return true;
}
// Only try to create a symbol+offset expression if there is no relocation.
return false;
}
// Interpret Value as a branch target.
if (IsBranch == false)
return false;
uint64_t UValue = Value;
// FIXME: map instead of looping each time?
error_code ec;
for (symbol_iterator SI = Obj->begin_symbols(),
SE = Obj->end_symbols();
SI != SE;
SI.increment(ec)) {
if (ec) break;
uint64_t SymAddr; SI->getAddress(SymAddr);
uint64_t SymSize; SI->getSize(SymSize);
StringRef SymName; SI->getName(SymName);
SymbolRef::Type SymType; SI->getType(SymType);
if (SymAddr == UnknownAddressOrSize || SymSize == UnknownAddressOrSize
|| SymName.empty() || SymType != SymbolRef::ST_Function)
continue;
if ( SymAddr == UValue ||
(SymAddr <= UValue && SymAddr + SymSize > UValue)) {
MCSymbol *Sym = Ctx.GetOrCreateSymbol(SymName);
const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
if (SymAddr != UValue) {
const MCExpr *Off = MCConstantExpr::Create(UValue - SymAddr, Ctx);
Expr = MCBinaryExpr::CreateAdd(Expr, Off, Ctx);
}
MI.addOperand(MCOperand::CreateExpr(Expr));
return true;
}
}
return false;
}
void MCObjectSymbolizer::
tryAddingPcLoadReferenceComment(raw_ostream &cStream,
int64_t Value, uint64_t Address) {
}
MCObjectSymbolizer *
MCObjectSymbolizer::createObjectSymbolizer(MCContext &Ctx,
OwningPtr<MCRelocationInfo> &RelInfo,
const ObjectFile *Obj) {
if (const MachOObjectFile *MachOOF = dyn_cast<MachOObjectFile>(Obj)) {
return new MCMachObjectSymbolizer(Ctx, RelInfo, MachOOF);
}
return new MCObjectSymbolizer(Ctx, RelInfo, Obj);
}
// SortedSections implementation.
static bool SectionStartsBefore(const SectionRef &S, uint64_t Addr) {
uint64_t SAddr; S.getAddress(SAddr);
return SAddr < Addr;
}
MCObjectSymbolizer::SortedSectionList::const_iterator
MCObjectSymbolizer::findSectionContaining(uint64_t Addr) const {
SortedSectionList::const_iterator
EndIt = SortedSections.end(),
It = std::lower_bound(SortedSections.begin(), EndIt,
Addr, SectionStartsBefore);
if (It == EndIt)
return It;
uint64_t SAddr; It->getAddress(SAddr);
uint64_t SSize; It->getSize(SSize);
if (Addr >= SAddr + SSize)
return EndIt;
return It;
}
void MCObjectSymbolizer::insertSection(SectionRef Sec) {
uint64_t SAddr; Sec.getAddress(SAddr);
uint64_t SSize; Sec.getSize(SSize);
SortedSectionList::iterator It = std::lower_bound(SortedSections.begin(),
SortedSections.end(),
SAddr,
SectionStartsBefore);
if (It != SortedSections.end()) {
uint64_t FoundSAddr; It->getAddress(FoundSAddr);
if (FoundSAddr < SAddr + SSize)
llvm_unreachable("Inserting overlapping sections");
}
SortedSections.insert(It, Sec);
}
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