llvm-objdump: implement printing for MachO __compact_unwind info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214509 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tim Northover 2014-08-01 13:07:19 +00:00
parent ea029d5b15
commit f28a36e527
7 changed files with 284 additions and 2 deletions

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@ -0,0 +1,27 @@
# RUN: llvm-objdump -unwind-info %p/Inputs/compact-unwind.macho-i386 | FileCheck %s
# CHECK: Contents of __compact_unwind section:
# CHECK: Entry at offset 0x0:
# CHECK: start: 0x0 __Z10test_throwv
# CHECK: length: 0x55
# CHECK: compact encoding: 0x01010005
# CHECK-NOT: personality function
# CHECK-NOT: LSDA
# CHECK: Entry at offset 0x14:
# CHECK: start: 0x60 __Z11test_catch1v
# CHECK: length: 0x6f
# CHECK: compact encoding: 0x41000000
# CHECK: personality function: 0x288 __pointers + 0x8
# CHECK: LSDA: 0x180 GCC_except_table1
# CHECK: Entry at offset 0x28:
# CHECK: start: 0xd0 __Z11test_catch2v
# CHECK: length: 0x75
# CHECK: compact encoding: 0x41000000
# CHECK: personality function: 0x288 __pointers + 0x8
# CHECK: LSDA: 0x1a8 GCC_except_table2
# CHECK: Entry at offset 0x3c:
# CHECK: start: 0x150 __Z3foov
# CHECK: length: 0x22
# CHECK: compact encoding: 0x01000000
# CHECK-NOT: personality function
# CHECK-NOT: LSDA

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@ -0,0 +1,27 @@
# RUN: llvm-objdump -unwind-info %p/Inputs/compact-unwind.macho-x86_64 | FileCheck %s
# CHECK: Contents of __compact_unwind section:
# CHECK: Entry at offset 0x0:
# CHECK: start: 0x1 __Z10test_throwv + 0x1
# CHECK: length: 0x44
# CHECK: compact encoding: 0x01000000
# CHECK-NOT: personality function
# CHECK-NOT: LSDA
# CHECK: Entry at offset 0x20:
# CHECK: start: 0x50 __Z11test_catch1v
# CHECK: length: 0x71
# CHECK: compact encoding: 0x41000000
# CHECK: personality function: 0x0 ___gxx_personality_v0
# CHECK: LSDA: 0x180 GCC_except_table1
# CHECK: Entry at offset 0x40:
# CHECK: start: 0xd0 __Z11test_catch2v
# CHECK: length: 0x77
# CHECK: compact encoding: 0x41000000
# CHECK: personality function: 0x0 ___gxx_personality_v0
# CHECK: LSDA: 0x1a8 GCC_except_table2
# CHECK: Entry at offset 0x60:
# CHECK: start: 0x150 __Z3foov
# CHECK: length: 0x25
# CHECK: compact encoding: 0x01000000
# CHECK-NOT: personality function
# CHECK-NOT: LSDA

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@ -30,6 +30,7 @@
#include "llvm/Support/Casting.h" #include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h" #include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h" #include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Format.h" #include "llvm/Support/Format.h"
#include "llvm/Support/GraphWriter.h" #include "llvm/Support/GraphWriter.h"
#include "llvm/Support/MachO.h" #include "llvm/Support/MachO.h"
@ -460,3 +461,225 @@ static void DisassembleInputMachO2(StringRef Filename,
} }
} }
} }
namespace {
struct CompactUnwindEntry {
uint32_t OffsetInSection;
uint64_t FunctionAddr;
uint32_t Length;
uint32_t CompactEncoding;
uint64_t PersonalityAddr;
uint64_t LSDAAddr;
RelocationRef FunctionReloc;
RelocationRef PersonalityReloc;
RelocationRef LSDAReloc;
CompactUnwindEntry(StringRef Contents, unsigned Offset, bool Is64)
: OffsetInSection(Offset) {
if (Is64)
read<uint64_t>(Contents.data() + Offset);
else
read<uint32_t>(Contents.data() + Offset);
}
private:
template<typename T>
static uint64_t readNext(const char *&Buf) {
using llvm::support::little;
using llvm::support::unaligned;
uint64_t Val = support::endian::read<T, little, unaligned>(Buf);
Buf += sizeof(T);
return Val;
}
template<typename UIntPtr>
void read(const char *Buf) {
FunctionAddr = readNext<UIntPtr>(Buf);
Length = readNext<uint32_t>(Buf);
CompactEncoding = readNext<uint32_t>(Buf);
PersonalityAddr = readNext<UIntPtr>(Buf);
LSDAAddr = readNext<UIntPtr>(Buf);
}
};
}
/// Given a relocation from __compact_unwind, consisting of the RelocationRef
/// and data being relocated, determine the best base Name and Addend to use for
/// display purposes.
///
/// 1. An Extern relocation will directly reference a symbol (and the data is
/// then already an addend), so use that.
/// 2. Otherwise the data is an offset in the object file's layout; try to find
// a symbol before it in the same section, and use the offset from there.
/// 3. Finally, if all that fails, fall back to an offset from the start of the
/// referenced section.
static void findUnwindRelocNameAddend(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const RelocationRef &Reloc,
uint64_t Addr,
StringRef &Name, uint64_t &Addend) {
if (Reloc.getSymbol() != Obj->symbol_end()) {
Reloc.getSymbol()->getName(Name);
Addend = Addr;
return;
}
auto RE = Obj->getRelocation(Reloc.getRawDataRefImpl());
SectionRef RelocSection = Obj->getRelocationSection(RE);
uint64_t SectionAddr;
RelocSection.getAddress(SectionAddr);
auto Sym = Symbols.upper_bound(Addr);
if (Sym == Symbols.begin()) {
// The first symbol in the object is after this reference, the best we can
// do is section-relative notation.
RelocSection.getName(Name);
Addend = Addr - SectionAddr;
return;
}
// Go back one so that SymbolAddress <= Addr.
--Sym;
section_iterator SymSection = Obj->section_end();
Sym->second.getSection(SymSection);
if (RelocSection == *SymSection) {
// There's a valid symbol in the same section before this reference.
Sym->second.getName(Name);
Addend = Addr - Sym->first;
return;
}
// There is a symbol before this reference, but it's in a different
// section. Probably not helpful to mention it, so use the section name.
RelocSection.getName(Name);
Addend = Addr - SectionAddr;
}
static void printUnwindRelocDest(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const RelocationRef &Reloc,
uint64_t Addr) {
StringRef Name;
uint64_t Addend;
findUnwindRelocNameAddend(Obj, Symbols, Reloc, Addr, Name, Addend);
outs() << Name;
if (Addend)
outs() << " + " << format("0x%x", Addend);
}
static void
printMachOCompactUnwindSection(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const SectionRef &CompactUnwind) {
assert(Obj->isLittleEndian() &&
"There should not be a big-endian .o with __compact_unwind");
bool Is64 = Obj->is64Bit();
uint32_t PointerSize = Is64 ? sizeof(uint64_t) : sizeof(uint32_t);
uint32_t EntrySize = 3 * PointerSize + 2 * sizeof(uint32_t);
StringRef Contents;
CompactUnwind.getContents(Contents);
SmallVector<CompactUnwindEntry, 4> CompactUnwinds;
// First populate the initial raw offsets, encodings and so on from the entry.
for (unsigned Offset = 0; Offset < Contents.size(); Offset += EntrySize) {
CompactUnwindEntry Entry(Contents.data(), Offset, Is64);
CompactUnwinds.push_back(Entry);
}
// Next we need to look at the relocations to find out what objects are
// actually being referred to.
for (const RelocationRef &Reloc : CompactUnwind.relocations()) {
uint64_t RelocAddress;
Reloc.getOffset(RelocAddress);
uint32_t EntryIdx = RelocAddress / EntrySize;
uint32_t OffsetInEntry = RelocAddress - EntryIdx * EntrySize;
CompactUnwindEntry &Entry = CompactUnwinds[EntryIdx];
if (OffsetInEntry == 0)
Entry.FunctionReloc = Reloc;
else if (OffsetInEntry == PointerSize + 2 * sizeof(uint32_t))
Entry.PersonalityReloc = Reloc;
else if (OffsetInEntry == 2 * PointerSize + 2 * sizeof(uint32_t))
Entry.LSDAReloc = Reloc;
else
llvm_unreachable("Unexpected relocation in __compact_unwind section");
}
// Finally, we're ready to print the data we've gathered.
outs() << "Contents of __compact_unwind section:\n";
for (auto &Entry : CompactUnwinds) {
outs() << " Entry at offset " << format("0x%x", Entry.OffsetInSection)
<< ":\n";
// 1. Start of the region this entry applies to.
outs() << " start: "
<< format("0x%x", Entry.FunctionAddr) << ' ';
printUnwindRelocDest(Obj, Symbols, Entry.FunctionReloc,
Entry.FunctionAddr);
outs() << '\n';
// 2. Length of the region this entry applies to.
outs() << " length: "
<< format("0x%x", Entry.Length) << '\n';
// 3. The 32-bit compact encoding.
outs() << " compact encoding: "
<< format("0x%08x", Entry.CompactEncoding) << '\n';
// 4. The personality function, if present.
if (Entry.PersonalityReloc.getObjectFile()) {
outs() << " personality function: "
<< format("0x%x", Entry.PersonalityAddr) << ' ';
printUnwindRelocDest(Obj, Symbols, Entry.PersonalityReloc,
Entry.PersonalityAddr);
outs() << '\n';
}
// 5. This entry's language-specific data area.
if (Entry.LSDAReloc.getObjectFile()) {
outs() << " LSDA: "
<< format("0x%x", Entry.LSDAAddr) << ' ';
printUnwindRelocDest(Obj, Symbols, Entry.LSDAReloc, Entry.LSDAAddr);
outs() << '\n';
}
}
}
void llvm::printMachOUnwindInfo(const MachOObjectFile *Obj) {
std::map<uint64_t, SymbolRef> Symbols;
for (const SymbolRef &SymRef : Obj->symbols()) {
// Discard any undefined or absolute symbols. They're not going to take part
// in the convenience lookup for unwind info and just take up resources.
section_iterator Section = Obj->section_end();
SymRef.getSection(Section);
if (Section == Obj->section_end())
continue;
uint64_t Addr;
SymRef.getAddress(Addr);
Symbols.insert(std::make_pair(Addr, SymRef));
}
for (const SectionRef &Section : Obj->sections()) {
StringRef SectName;
Section.getName(SectName);
if (SectName == "__compact_unwind")
printMachOCompactUnwindSection(Obj, Symbols, Section);
else if (SectName == "__unwind_info")
outs() << "llvm-objdump: warning: unhandled __unwind_info section\n";
else if (SectName == "__eh_frame")
outs() << "llvm-objdump: warning: unhandled __eh_frame section\n";
}
}

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@ -813,10 +813,12 @@ static void PrintUnwindInfo(const ObjectFile *o) {
if (const COFFObjectFile *coff = dyn_cast<COFFObjectFile>(o)) { if (const COFFObjectFile *coff = dyn_cast<COFFObjectFile>(o)) {
printCOFFUnwindInfo(coff); printCOFFUnwindInfo(coff);
} else { } else if (const MachOObjectFile *MachO = dyn_cast<MachOObjectFile>(o))
printMachOUnwindInfo(MachO);
else {
// TODO: Extract DWARF dump tool to objdump. // TODO: Extract DWARF dump tool to objdump.
errs() << "This operation is only currently supported " errs() << "This operation is only currently supported "
"for COFF object files.\n"; "for COFF and MachO object files.\n";
return; return;
} }
} }

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@ -18,6 +18,7 @@
namespace llvm { namespace llvm {
namespace object { namespace object {
class COFFObjectFile; class COFFObjectFile;
class MachOObjectFile;
class ObjectFile; class ObjectFile;
class RelocationRef; class RelocationRef;
} }
@ -31,6 +32,8 @@ bool RelocAddressLess(object::RelocationRef a, object::RelocationRef b);
void DumpBytes(StringRef bytes); void DumpBytes(StringRef bytes);
void DisassembleInputMachO(StringRef Filename); void DisassembleInputMachO(StringRef Filename);
void printCOFFUnwindInfo(const object::COFFObjectFile* o); void printCOFFUnwindInfo(const object::COFFObjectFile* o);
void printMachOUnwindInfo(const object::MachOObjectFile* o);
void printELFFileHeader(const object::ObjectFile *o); void printELFFileHeader(const object::ObjectFile *o);
void printCOFFFileHeader(const object::ObjectFile *o); void printCOFFFileHeader(const object::ObjectFile *o);