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llvm-objdump: print contents of MachO __unwind_info sections

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215437 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tim Northover
2014-08-12 11:52:59 +00:00
parent 99cd10fe11
commit 48bfab80aa
5 changed files with 306 additions and 11 deletions
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260
tools/llvm-objdump/MachODump.cpp
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@@ -471,7 +471,22 @@ static void DisassembleInputMachO2(StringRef Filename,
}
}
//===----------------------------------------------------------------------===//
// __compact_unwind section dumping
//===----------------------------------------------------------------------===//
namespace {
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;
}
struct CompactUnwindEntry {
uint32_t OffsetInSection;
@@ -494,16 +509,6 @@ struct CompactUnwindEntry {
}
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);
@@ -665,6 +670,239 @@ printMachOCompactUnwindSection(const MachOObjectFile *Obj,
}
}
//===----------------------------------------------------------------------===//
// __unwind_info section dumping
//===----------------------------------------------------------------------===//
static void printRegularSecondLevelUnwindPage(const char *PageStart) {
const char *Pos = PageStart;
uint32_t Kind = readNext<uint32_t>(Pos);
(void)Kind;
assert(Kind == 2 && "kind for a regular 2nd level index should be 2");
uint16_t EntriesStart = readNext<uint16_t>(Pos);
uint16_t NumEntries = readNext<uint16_t>(Pos);
Pos = PageStart + EntriesStart;
for (unsigned i = 0; i < NumEntries; ++i) {
uint32_t FunctionOffset = readNext<uint32_t>(Pos);
uint32_t Encoding = readNext<uint32_t>(Pos);
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, FunctionOffset) << ", "
<< "encoding="
<< format("0x%08" PRIx32, Encoding)
<< '\n';
}
}
static void printCompressedSecondLevelUnwindPage(
const char *PageStart, uint32_t FunctionBase,
const SmallVectorImpl<uint32_t> &CommonEncodings) {
const char *Pos = PageStart;
uint32_t Kind = readNext<uint32_t>(Pos);
(void)Kind;
assert(Kind == 3 && "kind for a compressed 2nd level index should be 3");
uint16_t EntriesStart = readNext<uint16_t>(Pos);
uint16_t NumEntries = readNext<uint16_t>(Pos);
uint16_t EncodingsStart = readNext<uint16_t>(Pos);
readNext<uint16_t>(Pos);
auto PageEncodings = (support::ulittle32_t *)(PageStart + EncodingsStart);
Pos = PageStart + EntriesStart;
for (unsigned i = 0; i < NumEntries; ++i) {
uint32_t Entry = readNext<uint32_t>(Pos);
uint32_t FunctionOffset = FunctionBase + (Entry & 0xffffff);
uint32_t EncodingIdx = Entry >> 24;
uint32_t Encoding;
if (EncodingIdx < CommonEncodings.size())
Encoding = CommonEncodings[EncodingIdx];
else
Encoding = PageEncodings[EncodingIdx - CommonEncodings.size()];
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, FunctionOffset) << ", "
<< "encoding[" << EncodingIdx << "]="
<< format("0x%08" PRIx32, Encoding)
<< '\n';
}
}
static void
printMachOUnwindInfoSection(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const SectionRef &UnwindInfo) {
assert(Obj->isLittleEndian() &&
"There should not be a big-endian .o with __unwind_info");
outs() << "Contents of __unwind_info section:\n";
StringRef Contents;
UnwindInfo.getContents(Contents);
const char *Pos = Contents.data();
//===----------------------------------
// Section header
//===----------------------------------
uint32_t Version = readNext<uint32_t>(Pos);
outs() << " Version: "
<< format("0x%" PRIx32, Version) << '\n';
assert(Version == 1 && "only understand version 1");
uint32_t CommonEncodingsStart = readNext<uint32_t>(Pos);
outs() << " Common encodings array section offset: "
<< format("0x%" PRIx32, CommonEncodingsStart) << '\n';
uint32_t NumCommonEncodings = readNext<uint32_t>(Pos);
outs() << " Number of common encodings in array: "
<< format("0x%" PRIx32, NumCommonEncodings) << '\n';
uint32_t PersonalitiesStart = readNext<uint32_t>(Pos);
outs() << " Personality function array section offset: "
<< format("0x%" PRIx32, PersonalitiesStart) << '\n';
uint32_t NumPersonalities = readNext<uint32_t>(Pos);
outs() << " Number of personality functions in array: "
<< format("0x%" PRIx32, NumPersonalities) << '\n';
uint32_t IndicesStart = readNext<uint32_t>(Pos);
outs() << " Index array section offset: "
<< format("0x%" PRIx32, IndicesStart) << '\n';
uint32_t NumIndices = readNext<uint32_t>(Pos);
outs() << " Number of indices in array: "
<< format("0x%" PRIx32, NumIndices) << '\n';
//===----------------------------------
// A shared list of common encodings
//===----------------------------------
// These occupy indices in the range [0, N] whenever an encoding is referenced
// from a compressed 2nd level index table. In practice the linker only
// creates ~128 of these, so that indices are available to embed encodings in
// the 2nd level index.
SmallVector<uint32_t, 64> CommonEncodings;
outs() << " Common encodings: (count = " << NumCommonEncodings << ")\n";
Pos = Contents.data() + CommonEncodingsStart;
for (unsigned i = 0; i < NumCommonEncodings; ++i) {
uint32_t Encoding = readNext<uint32_t>(Pos);
CommonEncodings.push_back(Encoding);
outs() << " encoding[" << i << "]: " << format("0x%08" PRIx32, Encoding)
<< '\n';
}
//===----------------------------------
// Personality functions used in this executable
//===----------------------------------
// There should be only a handful of these (one per source language,
// roughly). Particularly since they only get 2 bits in the compact encoding.
outs() << " Personality functions: (count = " << NumPersonalities << ")\n";
Pos = Contents.data() + PersonalitiesStart;
for (unsigned i = 0; i < NumPersonalities; ++i) {
uint32_t PersonalityFn = readNext<uint32_t>(Pos);
outs() << " personality[" << i + 1
<< "]: " << format("0x%08" PRIx32, PersonalityFn) << '\n';
}
//===----------------------------------
// The level 1 index entries
//===----------------------------------
// These specify an approximate place to start searching for the more detailed
// information, sorted by PC.
struct IndexEntry {
uint32_t FunctionOffset;
uint32_t SecondLevelPageStart;
uint32_t LSDAStart;
};
SmallVector<IndexEntry, 4> IndexEntries;
outs() << " Top level indices: (count = " << NumIndices << ")\n";
Pos = Contents.data() + IndicesStart;
for (unsigned i = 0; i < NumIndices; ++i) {
IndexEntry Entry;
Entry.FunctionOffset = readNext<uint32_t>(Pos);
Entry.SecondLevelPageStart = readNext<uint32_t>(Pos);
Entry.LSDAStart = readNext<uint32_t>(Pos);
IndexEntries.push_back(Entry);
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, Entry.FunctionOffset) << ", "
<< "2nd level page offset="
<< format("0x%08" PRIx32, Entry.SecondLevelPageStart) << ", "
<< "LSDA offset="
<< format("0x%08" PRIx32, Entry.LSDAStart) << '\n';
}
//===----------------------------------
// Next come the LSDA tables
//===----------------------------------
// The LSDA layout is rather implicit: it's a contiguous array of entries from
// the first top-level index's LSDAOffset to the last (sentinel).
outs() << " LSDA descriptors:\n";
Pos = Contents.data() + IndexEntries[0].LSDAStart;
int NumLSDAs = (IndexEntries.back().LSDAStart - IndexEntries[0].LSDAStart) /
(2 * sizeof(uint32_t));
for (int i = 0; i < NumLSDAs; ++i) {
uint32_t FunctionOffset = readNext<uint32_t>(Pos);
uint32_t LSDAOffset = readNext<uint32_t>(Pos);
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, FunctionOffset) << ", "
<< "LSDA offset="
<< format("0x%08" PRIx32, LSDAOffset) << '\n';
}
//===----------------------------------
// Finally, the 2nd level indices
//===----------------------------------
// Generally these are 4K in size, and have 2 possible forms:
// + Regular stores up to 511 entries with disparate encodings
// + Compressed stores up to 1021 entries if few enough compact encoding
// values are used.
outs() << " Second level indices:\n";
for (unsigned i = 0; i < IndexEntries.size() - 1; ++i) {
// The final sentinel top-level index has no associated 2nd level page
if (IndexEntries[i].SecondLevelPageStart == 0)
break;
outs() << " Second level index[" << i << "]: "
<< "offset in section="
<< format("0x%08" PRIx32, IndexEntries[i].SecondLevelPageStart)
<< ", "
<< "base function offset="
<< format("0x%08" PRIx32, IndexEntries[i].FunctionOffset) << '\n';
Pos = Contents.data() + IndexEntries[i].SecondLevelPageStart;
uint32_t Kind = *(support::ulittle32_t *)Pos;
if (Kind == 2)
printRegularSecondLevelUnwindPage(Pos);
else if (Kind == 3)
printCompressedSecondLevelUnwindPage(Pos, IndexEntries[i].FunctionOffset,
CommonEncodings);
else
llvm_unreachable("Do not know how to print this kind of 2nd level page");
}
}
void llvm::printMachOUnwindInfo(const MachOObjectFile *Obj) {
std::map<uint64_t, SymbolRef> Symbols;
for (const SymbolRef &SymRef : Obj->symbols()) {
@@ -686,7 +924,7 @@ void llvm::printMachOUnwindInfo(const MachOObjectFile *Obj) {
if (SectName == "__compact_unwind")
printMachOCompactUnwindSection(Obj, Symbols, Section);
else if (SectName == "__unwind_info")
outs() << "llvm-objdump: warning: unhandled __unwind_info section\n";
printMachOUnwindInfoSection(Obj, Symbols, Section);
else if (SectName == "__eh_frame")
outs() << "llvm-objdump: warning: unhandled __eh_frame section\n";