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//===--- DwarfCFIEHPrinter.h - DWARF-based Unwind Information Printer -----===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_READOBJ_DWARFCFIEHPRINTER_H
#define LLVM_TOOLS_LLVM_READOBJ_DWARFCFIEHPRINTER_H
#include "Error.h"
#include "llvm-readobj.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/Object/ELF.h"
#include "llvm/Object/ELFTypes.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ScopedPrinter.h"
#include "llvm/Support/Debug.h"
#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/type_traits.h"
namespace llvm {
namespace DwarfCFIEH {
template <typename ELFT>
class PrinterContext {
ScopedPrinter &W;
const object::ELFObjectFile<ELFT> *ObjF;
void printEHFrameHdr(uint64_t Offset, uint64_t Address, uint64_t Size) const;
void printEHFrame(const typename ELFT::Shdr *EHFrameShdr) const;
public:
PrinterContext(ScopedPrinter &W, const object::ELFObjectFile<ELFT> *ObjF)
: W(W), ObjF(ObjF) {}
void printUnwindInformation() const;
};
template <class ELFO>
static const typename ELFO::Elf_Shdr *findSectionByAddress(const ELFO *Obj,
uint64_t Addr) {
auto Sections = Obj->sections();
if (Error E = Sections.takeError())
reportError(toString(std::move(E)));
for (const auto &Shdr : *Sections)
if (Shdr.sh_addr == Addr)
return &Shdr;
return nullptr;
}
template <typename ELFT>
void PrinterContext<ELFT>::printUnwindInformation() const {
const object::ELFFile<ELFT> *Obj = ObjF->getELFFile();
const typename ELFT::Phdr *EHFramePhdr = nullptr;
auto PHs = Obj->program_headers();
if (Error E = PHs.takeError())
reportError(toString(std::move(E)));
for (const auto &Phdr : *PHs) {
if (Phdr.p_type == ELF::PT_GNU_EH_FRAME) {
EHFramePhdr = &Phdr;
if (Phdr.p_memsz != Phdr.p_filesz)
reportError("p_memsz does not match p_filesz for GNU_EH_FRAME");
break;
}
}
if (EHFramePhdr)
printEHFrameHdr(EHFramePhdr->p_offset, EHFramePhdr->p_vaddr,
EHFramePhdr->p_memsz);
auto Sections = Obj->sections();
if (Error E = Sections.takeError())
reportError(toString(std::move(E)));
for (const auto &Shdr : *Sections) {
auto SectionName = Obj->getSectionName(&Shdr);
if (Error E = SectionName.takeError())
reportError(toString(std::move(E)));
if (*SectionName == ".eh_frame")
printEHFrame(&Shdr);
}
}
template <typename ELFT>
void PrinterContext<ELFT>::printEHFrameHdr(uint64_t EHFrameHdrOffset,
uint64_t EHFrameHdrAddress,
uint64_t EHFrameHdrSize) const {
ListScope L(W, "EH_FRAME Header");
W.startLine() << format("Address: 0x%" PRIx64 "\n", EHFrameHdrAddress);
W.startLine() << format("Offset: 0x%" PRIx64 "\n", EHFrameHdrOffset);
W.startLine() << format("Size: 0x%" PRIx64 "\n", EHFrameHdrSize);
const object::ELFFile<ELFT> *Obj = ObjF->getELFFile();
const auto *EHFrameHdrShdr = findSectionByAddress(Obj, EHFrameHdrAddress);
if (EHFrameHdrShdr) {
auto SectionName = Obj->getSectionName(EHFrameHdrShdr);
if (Error E = SectionName.takeError())
reportError(toString(std::move(E)));
W.printString("Corresponding Section", *SectionName);
}
DataExtractor DE(
StringRef(reinterpret_cast<const char *>(Obj->base()) + EHFrameHdrOffset,
EHFrameHdrSize),
ELFT::TargetEndianness == support::endianness::little,
ELFT::Is64Bits ? 8 : 4);
DictScope D(W, "Header");
uint32_t Offset = 0;
auto Version = DE.getU8(&Offset);
W.printNumber("version", Version);
if (Version != 1)
reportError("only version 1 of .eh_frame_hdr is supported");
uint64_t EHFramePtrEnc = DE.getU8(&Offset);
W.startLine() << format("eh_frame_ptr_enc: 0x%" PRIx64 "\n", EHFramePtrEnc);
if (EHFramePtrEnc != (dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4))
reportError("unexpected encoding eh_frame_ptr_enc");
uint64_t FDECountEnc = DE.getU8(&Offset);
W.startLine() << format("fde_count_enc: 0x%" PRIx64 "\n", FDECountEnc);
if (FDECountEnc != dwarf::DW_EH_PE_udata4)
reportError("unexpected encoding fde_count_enc");
uint64_t TableEnc = DE.getU8(&Offset);
W.startLine() << format("table_enc: 0x%" PRIx64 "\n", TableEnc);
if (TableEnc != (dwarf::DW_EH_PE_datarel | dwarf::DW_EH_PE_sdata4))
reportError("unexpected encoding table_enc");
auto EHFramePtr = DE.getSigned(&Offset, 4) + EHFrameHdrAddress + 4;
W.startLine() << format("eh_frame_ptr: 0x%" PRIx64 "\n", EHFramePtr);
auto FDECount = DE.getUnsigned(&Offset, 4);
W.printNumber("fde_count", FDECount);
unsigned NumEntries = 0;
uint64_t PrevPC = 0;
while (Offset + 8 <= EHFrameHdrSize && NumEntries < FDECount) {
DictScope D(W, std::string("entry ") + std::to_string(NumEntries));
auto InitialPC = DE.getSigned(&Offset, 4) + EHFrameHdrAddress;
W.startLine() << format("initial_location: 0x%" PRIx64 "\n", InitialPC);
auto Address = DE.getSigned(&Offset, 4) + EHFrameHdrAddress;
W.startLine() << format("address: 0x%" PRIx64 "\n", Address);
if (InitialPC < PrevPC)
reportError("initial_location is out of order");
PrevPC = InitialPC;
++NumEntries;
}
}
template <typename ELFT>
void PrinterContext<ELFT>::printEHFrame(
const typename ELFT::Shdr *EHFrameShdr) const {
uint64_t Address = EHFrameShdr->sh_addr;
uint64_t ShOffset = EHFrameShdr->sh_offset;
W.startLine() << format(".eh_frame section at offset 0x%" PRIx64
" address 0x%" PRIx64 ":\n",
ShOffset, Address);
W.indent();
const object::ELFFile<ELFT> *Obj = ObjF->getELFFile();
auto Result = Obj->getSectionContents(EHFrameShdr);
if (Error E = Result.takeError())
reportError(toString(std::move(E)));
auto Contents = Result.get();
DWARFDataExtractor DE(
StringRef(reinterpret_cast<const char *>(Contents.data()),
Contents.size()),
ELFT::TargetEndianness == support::endianness::little,
ELFT::Is64Bits ? 8 : 4);
DWARFDebugFrame EHFrame(Triple::ArchType(ObjF->getArch()), /*IsEH=*/true,
/*EHFrameAddress=*/Address);
EHFrame.parse(DE);
for (const auto &Entry : EHFrame) {
if (const auto *CIE = dyn_cast<dwarf::CIE>(&Entry)) {
W.startLine() << format("[0x%" PRIx64 "] CIE length=%" PRIu64 "\n",
Address + CIE->getOffset(),
CIE->getLength());
W.indent();
W.printNumber("version", CIE->getVersion());
W.printString("augmentation", CIE->getAugmentationString());
W.printNumber("code_alignment_factor", CIE->getCodeAlignmentFactor());
W.printNumber("data_alignment_factor", CIE->getDataAlignmentFactor());
W.printNumber("return_address_register", CIE->getReturnAddressRegister());
W.getOStream() << "\n";
W.startLine() << "Program:\n";
W.indent();
CIE->cfis().dump(W.getOStream(), nullptr, W.getIndentLevel());
W.unindent();
W.unindent();
W.getOStream() << "\n";
} else if (const auto *FDE = dyn_cast<dwarf::FDE>(&Entry)) {
W.startLine() << format("[0x%" PRIx64 "] FDE length=%" PRIu64
" cie=[0x%" PRIx64 "]\n",
Address + FDE->getOffset(),
FDE->getLength(),
Address + FDE->getLinkedCIE()->getOffset());
W.indent();
W.startLine() << format("initial_location: 0x%" PRIx64 "\n",
FDE->getInitialLocation());
W.startLine()
<< format("address_range: 0x%" PRIx64 " (end : 0x%" PRIx64 ")\n",
FDE->getAddressRange(),
FDE->getInitialLocation() + FDE->getAddressRange());
W.getOStream() << "\n";
W.startLine() << "Program:\n";
W.indent();
FDE->cfis().dump(W.getOStream(), nullptr, W.getIndentLevel());
W.unindent();
W.unindent();
W.getOStream() << "\n";
} else {
llvm_unreachable("unexpected DWARF frame kind");
}
}
W.unindent();
}
}
}
#endif
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