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[llvm-objdump] - Move getRelocationValueString and dependenices out o…
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…f the llvm-objdump.cpp

getRelocationValueString is a dispatcher function that calls the
corresponding ELF/COFF/Wasm/MachO implementations
that currently live in the llvm-objdump.cpp file.

These implementations better be moved to ELFDump.cpp,
COFFDump.cpp and other corresponding files, to move platform specific
implementation out from the common logic.

The patch does that. Also, I had to move ToolSectionFilter helper
and SectionFilterIterator, SectionFilter to a header to make them
available across the objdump code.

Differential revision: https://reviews.llvm.org/D56842

llvm-svn: 351545
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George Rimar committed Jan 18, 2019
1 parent 77364be commit c196488
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Showing 6 changed files with 459 additions and 433 deletions.
13 changes: 13 additions & 0 deletions llvm/tools/llvm-objdump/COFFDump.cpp
View file
Expand Up @@ -469,6 +469,19 @@ static bool getPDataSection(const COFFObjectFile *Obj,
return false;
}

std::error_code
llvm::getCOFFRelocationValueString(const COFFObjectFile *Obj,
const RelocationRef &Rel,
SmallVectorImpl<char> &Result) {
symbol_iterator SymI = Rel.getSymbol();
Expected<StringRef> SymNameOrErr = SymI->getName();
if (!SymNameOrErr)
return errorToErrorCode(SymNameOrErr.takeError());
StringRef SymName = *SymNameOrErr;
Result.append(SymName.begin(), SymName.end());
return std::error_code();
}

static void printWin64EHUnwindInfo(const Win64EH::UnwindInfo *UI) {
// The casts to int are required in order to output the value as number.
// Without the casts the value would be interpreted as char data (which
Expand Down
82 changes: 82 additions & 0 deletions llvm/tools/llvm-objdump/ELFDump.cpp
View file
Expand Up @@ -13,6 +13,7 @@
//===----------------------------------------------------------------------===//

#include "llvm-objdump.h"
#include "llvm/Demangle/Demangle.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/MathExtras.h"
Expand Down Expand Up @@ -51,6 +52,87 @@ Expected<StringRef> getDynamicStrTab(const ELFFile<ELFT> *Elf) {
return createError("dynamic string table not found");
}

template <class ELFT>
static std::error_code getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
const RelocationRef &RelRef,
SmallVectorImpl<char> &Result) {
typedef typename ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;
typedef typename ELFObjectFile<ELFT>::Elf_Shdr Elf_Shdr;
typedef typename ELFObjectFile<ELFT>::Elf_Rela Elf_Rela;

const ELFFile<ELFT> &EF = *Obj->getELFFile();
DataRefImpl Rel = RelRef.getRawDataRefImpl();
auto SecOrErr = EF.getSection(Rel.d.a);
if (!SecOrErr)
return errorToErrorCode(SecOrErr.takeError());

int64_t Addend = 0;
// If there is no Symbol associated with the relocation, we set the undef
// boolean value to 'true'. This will prevent us from calling functions that
// requires the relocation to be associated with a symbol.
//
// In SHT_REL case we would need to read the addend from section data.
// GNU objdump does not do that and we just follow for simplicity atm.
bool Undef = false;
if ((*SecOrErr)->sh_type == ELF::SHT_RELA) {
const Elf_Rela *ERela = Obj->getRela(Rel);
Addend = ERela->r_addend;
Undef = ERela->getSymbol(false) == 0;
} else if ((*SecOrErr)->sh_type != ELF::SHT_REL) {
return object_error::parse_failed;
}

// Default scheme is to print Target, as well as "+ <addend>" for nonzero
// addend. Should be acceptable for all normal purposes.
std::string FmtBuf;
raw_string_ostream Fmt(FmtBuf);

if (!Undef) {
symbol_iterator SI = RelRef.getSymbol();
const Elf_Sym *Sym = Obj->getSymbol(SI->getRawDataRefImpl());
if (Sym->getType() == ELF::STT_SECTION) {
Expected<section_iterator> SymSI = SI->getSection();
if (!SymSI)
return errorToErrorCode(SymSI.takeError());
const Elf_Shdr *SymSec = Obj->getSection((*SymSI)->getRawDataRefImpl());
auto SecName = EF.getSectionName(SymSec);
if (!SecName)
return errorToErrorCode(SecName.takeError());
Fmt << *SecName;
} else {
Expected<StringRef> SymName = SI->getName();
if (!SymName)
return errorToErrorCode(SymName.takeError());
if (Demangle)
Fmt << demangle(*SymName);
else
Fmt << *SymName;
}
} else {
Fmt << "*ABS*";
}

if (Addend != 0)
Fmt << (Addend < 0 ? "" : "+") << Addend;
Fmt.flush();
Result.append(FmtBuf.begin(), FmtBuf.end());
return std::error_code();
}

std::error_code
llvm::getELFRelocationValueString(const ELFObjectFileBase *Obj,
const RelocationRef &Rel,
SmallVectorImpl<char> &Result) {
if (auto *ELF32LE = dyn_cast<ELF32LEObjectFile>(Obj))
return getRelocationValueString(ELF32LE, Rel, Result);
if (auto *ELF64LE = dyn_cast<ELF64LEObjectFile>(Obj))
return getRelocationValueString(ELF64LE, Rel, Result);
if (auto *ELF32BE = dyn_cast<ELF32BEObjectFile>(Obj))
return getRelocationValueString(ELF32BE, Rel, Result);
auto *ELF64BE = cast<ELF64BEObjectFile>(Obj);
return getRelocationValueString(ELF64BE, Rel, Result);
}

template <class ELFT>
void printDynamicSection(const ELFFile<ELFT> *Elf, StringRef Filename) {
auto ProgramHeaderOrError = Elf->program_headers();
Expand Down
258 changes: 258 additions & 0 deletions llvm/tools/llvm-objdump/MachODump.cpp
View file
Expand Up @@ -342,6 +342,264 @@ static void getSectionsAndSymbols(MachOObjectFile *MachOObj,
}
}

static void printRelocationTargetName(const MachOObjectFile *O,
const MachO::any_relocation_info &RE,
raw_string_ostream &Fmt) {
// Target of a scattered relocation is an address. In the interest of
// generating pretty output, scan through the symbol table looking for a
// symbol that aligns with that address. If we find one, print it.
// Otherwise, we just print the hex address of the target.
if (O->isRelocationScattered(RE)) {
uint32_t Val = O->getPlainRelocationSymbolNum(RE);

for (const SymbolRef &Symbol : O->symbols()) {
Expected<uint64_t> Addr = Symbol.getAddress();
if (!Addr)
report_error(O->getFileName(), Addr.takeError());
if (*Addr != Val)
continue;
Expected<StringRef> Name = Symbol.getName();
if (!Name)
report_error(O->getFileName(), Name.takeError());
Fmt << *Name;
return;
}

// If we couldn't find a symbol that this relocation refers to, try
// to find a section beginning instead.
for (const SectionRef &Section : ToolSectionFilter(*O)) {
std::error_code ec;

StringRef Name;
uint64_t Addr = Section.getAddress();
if (Addr != Val)
continue;
if ((ec = Section.getName(Name)))
report_error(O->getFileName(), ec);
Fmt << Name;
return;
}

Fmt << format("0x%x", Val);
return;
}

StringRef S;
bool isExtern = O->getPlainRelocationExternal(RE);
uint64_t Val = O->getPlainRelocationSymbolNum(RE);

if (O->getAnyRelocationType(RE) == MachO::ARM64_RELOC_ADDEND) {
Fmt << format("0x%0" PRIx64, Val);
return;
}

if (isExtern) {
symbol_iterator SI = O->symbol_begin();
advance(SI, Val);
Expected<StringRef> SOrErr = SI->getName();
if (!SOrErr)
report_error(O->getFileName(), SOrErr.takeError());
S = *SOrErr;
} else {
section_iterator SI = O->section_begin();
// Adjust for the fact that sections are 1-indexed.
if (Val == 0) {
Fmt << "0 (?,?)";
return;
}
uint32_t I = Val - 1;
while (I != 0 && SI != O->section_end()) {
--I;
advance(SI, 1);
}
if (SI == O->section_end())
Fmt << Val << " (?,?)";
else
SI->getName(S);
}

Fmt << S;
}

std::error_code
llvm::getMachORelocationValueString(const MachOObjectFile *Obj,
const RelocationRef &RelRef,
SmallVectorImpl<char> &Result) {
DataRefImpl Rel = RelRef.getRawDataRefImpl();
MachO::any_relocation_info RE = Obj->getRelocation(Rel);

unsigned Arch = Obj->getArch();

std::string FmtBuf;
raw_string_ostream Fmt(FmtBuf);
unsigned Type = Obj->getAnyRelocationType(RE);
bool IsPCRel = Obj->getAnyRelocationPCRel(RE);

// Determine any addends that should be displayed with the relocation.
// These require decoding the relocation type, which is triple-specific.

// X86_64 has entirely custom relocation types.
if (Arch == Triple::x86_64) {
switch (Type) {
case MachO::X86_64_RELOC_GOT_LOAD:
case MachO::X86_64_RELOC_GOT: {
printRelocationTargetName(Obj, RE, Fmt);
Fmt << "@GOT";
if (IsPCRel)
Fmt << "PCREL";
break;
}
case MachO::X86_64_RELOC_SUBTRACTOR: {
DataRefImpl RelNext = Rel;
Obj->moveRelocationNext(RelNext);
MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);

// X86_64_RELOC_SUBTRACTOR must be followed by a relocation of type
// X86_64_RELOC_UNSIGNED.
// NOTE: Scattered relocations don't exist on x86_64.
unsigned RType = Obj->getAnyRelocationType(RENext);
if (RType != MachO::X86_64_RELOC_UNSIGNED)
report_error(Obj->getFileName(), "Expected X86_64_RELOC_UNSIGNED after "
"X86_64_RELOC_SUBTRACTOR.");

// The X86_64_RELOC_UNSIGNED contains the minuend symbol;
// X86_64_RELOC_SUBTRACTOR contains the subtrahend.
printRelocationTargetName(Obj, RENext, Fmt);
Fmt << "-";
printRelocationTargetName(Obj, RE, Fmt);
break;
}
case MachO::X86_64_RELOC_TLV:
printRelocationTargetName(Obj, RE, Fmt);
Fmt << "@TLV";
if (IsPCRel)
Fmt << "P";
break;
case MachO::X86_64_RELOC_SIGNED_1:
printRelocationTargetName(Obj, RE, Fmt);
Fmt << "-1";
break;
case MachO::X86_64_RELOC_SIGNED_2:
printRelocationTargetName(Obj, RE, Fmt);
Fmt << "-2";
break;
case MachO::X86_64_RELOC_SIGNED_4:
printRelocationTargetName(Obj, RE, Fmt);
Fmt << "-4";
break;
default:
printRelocationTargetName(Obj, RE, Fmt);
break;
}
// X86 and ARM share some relocation types in common.
} else if (Arch == Triple::x86 || Arch == Triple::arm ||
Arch == Triple::ppc) {
// Generic relocation types...
switch (Type) {
case MachO::GENERIC_RELOC_PAIR: // prints no info
return std::error_code();
case MachO::GENERIC_RELOC_SECTDIFF: {
DataRefImpl RelNext = Rel;
Obj->moveRelocationNext(RelNext);
MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);

// X86 sect diff's must be followed by a relocation of type
// GENERIC_RELOC_PAIR.
unsigned RType = Obj->getAnyRelocationType(RENext);

if (RType != MachO::GENERIC_RELOC_PAIR)
report_error(Obj->getFileName(), "Expected GENERIC_RELOC_PAIR after "
"GENERIC_RELOC_SECTDIFF.");

printRelocationTargetName(Obj, RE, Fmt);
Fmt << "-";
printRelocationTargetName(Obj, RENext, Fmt);
break;
}
}

if (Arch == Triple::x86 || Arch == Triple::ppc) {
switch (Type) {
case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
DataRefImpl RelNext = Rel;
Obj->moveRelocationNext(RelNext);
MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);

// X86 sect diff's must be followed by a relocation of type
// GENERIC_RELOC_PAIR.
unsigned RType = Obj->getAnyRelocationType(RENext);
if (RType != MachO::GENERIC_RELOC_PAIR)
report_error(Obj->getFileName(), "Expected GENERIC_RELOC_PAIR after "
"GENERIC_RELOC_LOCAL_SECTDIFF.");

printRelocationTargetName(Obj, RE, Fmt);
Fmt << "-";
printRelocationTargetName(Obj, RENext, Fmt);
break;
}
case MachO::GENERIC_RELOC_TLV: {
printRelocationTargetName(Obj, RE, Fmt);
Fmt << "@TLV";
if (IsPCRel)
Fmt << "P";
break;
}
default:
printRelocationTargetName(Obj, RE, Fmt);
}
} else { // ARM-specific relocations
switch (Type) {
case MachO::ARM_RELOC_HALF:
case MachO::ARM_RELOC_HALF_SECTDIFF: {
// Half relocations steal a bit from the length field to encode
// whether this is an upper16 or a lower16 relocation.
bool isUpper = (Obj->getAnyRelocationLength(RE) & 0x1) == 1;

if (isUpper)
Fmt << ":upper16:(";
else
Fmt << ":lower16:(";
printRelocationTargetName(Obj, RE, Fmt);

DataRefImpl RelNext = Rel;
Obj->moveRelocationNext(RelNext);
MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);

// ARM half relocs must be followed by a relocation of type
// ARM_RELOC_PAIR.
unsigned RType = Obj->getAnyRelocationType(RENext);
if (RType != MachO::ARM_RELOC_PAIR)
report_error(Obj->getFileName(), "Expected ARM_RELOC_PAIR after "
"ARM_RELOC_HALF");

// NOTE: The half of the target virtual address is stashed in the
// address field of the secondary relocation, but we can't reverse
// engineer the constant offset from it without decoding the movw/movt
// instruction to find the other half in its immediate field.

// ARM_RELOC_HALF_SECTDIFF encodes the second section in the
// symbol/section pointer of the follow-on relocation.
if (Type == MachO::ARM_RELOC_HALF_SECTDIFF) {
Fmt << "-";
printRelocationTargetName(Obj, RENext, Fmt);
}

Fmt << ")";
break;
}
default: {
printRelocationTargetName(Obj, RE, Fmt);
}
}
}
} else
printRelocationTargetName(Obj, RE, Fmt);

Fmt.flush();
Result.append(FmtBuf.begin(), FmtBuf.end());
return std::error_code();
}

static void PrintIndirectSymbolTable(MachOObjectFile *O, bool verbose,
uint32_t n, uint32_t count,
uint32_t stride, uint64_t addr) {
Expand Down

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