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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189728 91177308-0d34-0410-b5e6-96231b3b80d8
311 lines
11 KiB
C++
311 lines
11 KiB
C++
//===-- lib/MC/MCObjectSymbolizer.cpp -------------------------------------===//
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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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#include "llvm/MC/MCObjectSymbolizer.h"
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#include "llvm/ADT/SmallString.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/MCInst.h"
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#include "llvm/MC/MCRelocationInfo.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Object/MachO.h"
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#include "llvm/Object/ELFObjectFile.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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using namespace llvm;
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using namespace object;
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//===- MCMachObjectSymbolizer ---------------------------------------------===//
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namespace {
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class MCMachObjectSymbolizer : public MCObjectSymbolizer {
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const MachOObjectFile *MOOF;
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// __TEXT;__stubs support.
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uint64_t StubsStart;
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uint64_t StubsCount;
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uint64_t StubSize;
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uint64_t StubsIndSymIndex;
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public:
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MCMachObjectSymbolizer(MCContext &Ctx, OwningPtr<MCRelocationInfo> &RelInfo,
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const MachOObjectFile *MOOF);
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StringRef findExternalFunctionAt(uint64_t Addr) LLVM_OVERRIDE;
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void tryAddingPcLoadReferenceComment(raw_ostream &cStream,
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int64_t Value,
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uint64_t Address) LLVM_OVERRIDE;
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};
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} // End unnamed namespace
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MCMachObjectSymbolizer::
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MCMachObjectSymbolizer(MCContext &Ctx, OwningPtr<MCRelocationInfo> &RelInfo,
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const MachOObjectFile *MOOF)
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: MCObjectSymbolizer(Ctx, RelInfo, MOOF), MOOF(MOOF),
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StubsStart(0), StubsCount(0), StubSize(0), StubsIndSymIndex(0) {
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error_code ec;
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for (section_iterator SI = MOOF->begin_sections(), SE = MOOF->end_sections();
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SI != SE; SI.increment(ec)) {
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if (ec) break;
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StringRef Name; SI->getName(Name);
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if (Name == "__stubs") {
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SectionRef StubsSec = *SI;
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if (MOOF->is64Bit()) {
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MachO::section_64 S = MOOF->getSection64(StubsSec.getRawDataRefImpl());
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StubsIndSymIndex = S.reserved1;
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StubSize = S.reserved2;
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} else {
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MachO::section S = MOOF->getSection(StubsSec.getRawDataRefImpl());
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StubsIndSymIndex = S.reserved1;
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StubSize = S.reserved2;
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}
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assert(StubSize && "Mach-O stub entry size can't be zero!");
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StubsSec.getAddress(StubsStart);
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StubsSec.getSize(StubsCount);
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StubsCount /= StubSize;
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}
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}
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}
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StringRef MCMachObjectSymbolizer::findExternalFunctionAt(uint64_t Addr) {
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// FIXME: also, this can all be done at the very beginning, by iterating over
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// all stubs and creating the calls to outside functions. Is it worth it
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// though?
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if (!StubSize)
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return StringRef();
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uint64_t StubIdx = (Addr - StubsStart) / StubSize;
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if (StubIdx >= StubsCount)
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return StringRef();
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uint32_t SymtabIdx =
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MOOF->getIndirectSymbolTableEntry(MOOF->getDysymtabLoadCommand(), StubIdx);
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StringRef SymName;
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symbol_iterator SI = MOOF->begin_symbols();
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error_code ec;
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for (uint32_t i = 0; i != SymtabIdx; ++i) {
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SI.increment(ec);
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}
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SI->getName(SymName);
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assert(SI != MOOF->end_symbols() && "Stub wasn't found in the symbol table!");
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assert(SymName.front() == '_' && "Mach-O symbol doesn't start with '_'!");
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return SymName.substr(1);
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}
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void MCMachObjectSymbolizer::
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tryAddingPcLoadReferenceComment(raw_ostream &cStream, int64_t Value,
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uint64_t Address) {
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if (const RelocationRef *R = findRelocationAt(Address)) {
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const MCExpr *RelExpr = RelInfo->createExprForRelocation(*R);
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if (!RelExpr || RelExpr->EvaluateAsAbsolute(Value) == false)
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return;
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}
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uint64_t Addr = Value;
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if (const SectionRef *S = findSectionContaining(Addr)) {
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StringRef Name; S->getName(Name);
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uint64_t SAddr; S->getAddress(SAddr);
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if (Name == "__cstring") {
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StringRef Contents;
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S->getContents(Contents);
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Contents = Contents.substr(Addr - SAddr);
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cStream << " ## literal pool for: "
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<< Contents.substr(0, Contents.find_first_of(0));
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}
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}
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}
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//===- MCObjectSymbolizer -------------------------------------------------===//
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MCObjectSymbolizer::MCObjectSymbolizer(MCContext &Ctx,
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OwningPtr<MCRelocationInfo> &RelInfo,
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const ObjectFile *Obj)
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: MCSymbolizer(Ctx, RelInfo), Obj(Obj), SortedSections(), AddrToReloc() {
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}
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bool MCObjectSymbolizer::
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tryAddingSymbolicOperand(MCInst &MI, raw_ostream &cStream,
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int64_t Value, uint64_t Address, bool IsBranch,
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uint64_t Offset, uint64_t InstSize) {
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if (IsBranch) {
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StringRef ExtFnName = findExternalFunctionAt((uint64_t)Value);
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if (!ExtFnName.empty()) {
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MCSymbol *Sym = Ctx.GetOrCreateSymbol(ExtFnName);
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const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
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MI.addOperand(MCOperand::CreateExpr(Expr));
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return true;
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}
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}
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if (const RelocationRef *R = findRelocationAt(Address + Offset)) {
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if (const MCExpr *RelExpr = RelInfo->createExprForRelocation(*R)) {
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MI.addOperand(MCOperand::CreateExpr(RelExpr));
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return true;
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}
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// Only try to create a symbol+offset expression if there is no relocation.
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return false;
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}
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// Interpret Value as a branch target.
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if (IsBranch == false)
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return false;
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uint64_t UValue = Value;
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// FIXME: map instead of looping each time?
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error_code ec;
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for (symbol_iterator SI = Obj->begin_symbols(), SE = Obj->end_symbols();
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SI != SE; SI.increment(ec)) {
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if (ec) break;
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uint64_t SymAddr; SI->getAddress(SymAddr);
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uint64_t SymSize; SI->getSize(SymSize);
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StringRef SymName; SI->getName(SymName);
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SymbolRef::Type SymType; SI->getType(SymType);
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if (SymAddr == UnknownAddressOrSize || SymSize == UnknownAddressOrSize
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|| SymName.empty() || SymType != SymbolRef::ST_Function)
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continue;
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if ( SymAddr == UValue ||
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(SymAddr <= UValue && SymAddr + SymSize > UValue)) {
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MCSymbol *Sym = Ctx.GetOrCreateSymbol(SymName);
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const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
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if (SymAddr != UValue) {
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const MCExpr *Off = MCConstantExpr::Create(UValue - SymAddr, Ctx);
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Expr = MCBinaryExpr::CreateAdd(Expr, Off, Ctx);
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}
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MI.addOperand(MCOperand::CreateExpr(Expr));
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return true;
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}
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}
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return false;
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}
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void MCObjectSymbolizer::
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tryAddingPcLoadReferenceComment(raw_ostream &cStream,
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int64_t Value, uint64_t Address) {
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}
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StringRef MCObjectSymbolizer::findExternalFunctionAt(uint64_t Addr) {
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return StringRef();
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}
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MCObjectSymbolizer *
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MCObjectSymbolizer::createObjectSymbolizer(MCContext &Ctx,
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OwningPtr<MCRelocationInfo> &RelInfo,
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const ObjectFile *Obj) {
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if (const MachOObjectFile *MOOF = dyn_cast<MachOObjectFile>(Obj))
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return new MCMachObjectSymbolizer(Ctx, RelInfo, MOOF);
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return new MCObjectSymbolizer(Ctx, RelInfo, Obj);
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}
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// SortedSections implementation.
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static bool SectionStartsBefore(const SectionRef &S, uint64_t Addr) {
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uint64_t SAddr; S.getAddress(SAddr);
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return SAddr < Addr;
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}
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const SectionRef *MCObjectSymbolizer::findSectionContaining(uint64_t Addr) {
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if (SortedSections.empty())
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buildSectionList();
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SortedSectionList::iterator
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EndIt = SortedSections.end(),
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It = std::lower_bound(SortedSections.begin(), EndIt,
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Addr, SectionStartsBefore);
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if (It == EndIt)
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return 0;
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uint64_t SAddr; It->getAddress(SAddr);
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uint64_t SSize; It->getSize(SSize);
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if (Addr >= SAddr + SSize)
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return 0;
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return &*It;
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}
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const RelocationRef *MCObjectSymbolizer::findRelocationAt(uint64_t Addr) {
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if (AddrToReloc.empty())
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buildRelocationByAddrMap();
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AddrToRelocMap::const_iterator RI = AddrToReloc.find(Addr);
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if (RI == AddrToReloc.end())
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return 0;
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return &RI->second;
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}
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void MCObjectSymbolizer::buildSectionList() {
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error_code ec;
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for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
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SI != SE; SI.increment(ec)) {
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if (ec) break;
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bool RequiredForExec; SI->isRequiredForExecution(RequiredForExec);
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if (RequiredForExec == false)
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continue;
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uint64_t SAddr; SI->getAddress(SAddr);
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uint64_t SSize; SI->getSize(SSize);
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SortedSectionList::iterator It = std::lower_bound(SortedSections.begin(),
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SortedSections.end(),
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SAddr,
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SectionStartsBefore);
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if (It != SortedSections.end()) {
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uint64_t FoundSAddr; It->getAddress(FoundSAddr);
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if (FoundSAddr < SAddr + SSize)
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llvm_unreachable("Inserting overlapping sections");
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}
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SortedSections.insert(It, *SI);
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}
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}
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void MCObjectSymbolizer::buildRelocationByAddrMap() {
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error_code ec;
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for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
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SI != SE; SI.increment(ec)) {
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if (ec) break;
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section_iterator RelSecI = SI->getRelocatedSection();
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if (RelSecI == Obj->end_sections())
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continue;
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uint64_t StartAddr; RelSecI->getAddress(StartAddr);
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uint64_t Size; RelSecI->getSize(Size);
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bool RequiredForExec; RelSecI->isRequiredForExecution(RequiredForExec);
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if (RequiredForExec == false || Size == 0)
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continue;
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for (relocation_iterator RI = SI->begin_relocations(),
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RE = SI->end_relocations();
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RI != RE;
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RI.increment(ec)) {
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if (ec) break;
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// FIXME: libObject is inconsistent regarding error handling. The
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// overwhelming majority of methods always return object_error::success,
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// and assert for simple errors.. Here, ELFObjectFile::getRelocationOffset
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// asserts when the file type isn't ET_REL.
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// This workaround handles x86-64 elf, the only one that has a relocinfo.
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uint64_t Offset;
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if (Obj->isELF()) {
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const ELF64LEObjectFile *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj);
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if (ELFObj == 0)
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break;
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if (ELFObj->getELFFile()->getHeader()->e_type == ELF::ET_REL) {
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RI->getOffset(Offset);
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Offset += StartAddr;
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} else {
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RI->getAddress(Offset);
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}
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} else {
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RI->getOffset(Offset);
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Offset += StartAddr;
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}
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// At a specific address, only keep the first relocation.
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if (AddrToReloc.find(Offset) == AddrToReloc.end())
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AddrToReloc[Offset] = *RI;
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}
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}
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}
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