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Merge "Move PC-only unwind frame generation to libunwindstack."

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Treehugger Robot 2020-03-30 17:49:35 +00:00 • committed by Gerrit Code Review
commit 6f6beb3cc0
3 changed files with 61 additions and 56 deletions
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60
debuggerd/libdebuggerd/gwp_asan.cpp
View file

@ -157,60 +157,6 @@ void GwpAsanCrashData::DumpCause(log_t* log) const {
error_string_, diff, byte_suffix, location_str, alloc_size, alloc_address);
}
// Build a frame for symbolization using the maps from the provided unwinder.
// The constructed frame contains just enough information to be used to
// symbolize a GWP-ASan stack trace.
static unwindstack::FrameData BuildFrame(unwindstack::Unwinder* unwinder, uintptr_t pc,
size_t frame_num) {
unwindstack::FrameData frame;
frame.num = frame_num;
unwindstack::Maps* maps = unwinder->GetMaps();
unwindstack::MapInfo* map_info = maps->Find(pc);
if (!map_info) {
frame.rel_pc = pc;
return frame;
}
unwindstack::ArchEnum arch = unwindstack::Regs::CurrentArch();
unwindstack::Elf* elf = map_info->GetElf(unwinder->GetProcessMemory(), arch);
uint64_t relative_pc = elf->GetRelPc(pc, map_info);
uint64_t pc_adjustment = unwindstack::GetPcAdjustment(relative_pc, elf, arch);
relative_pc -= pc_adjustment;
// The debug PC may be different if the PC comes from the JIT.
uint64_t debug_pc = relative_pc;
// If we don't have a valid ELF file, check the JIT.
if (!elf->valid()) {
unwindstack::JitDebug jit_debug(unwinder->GetProcessMemory());
uint64_t jit_pc = pc - pc_adjustment;
unwindstack::Elf* jit_elf = jit_debug.GetElf(maps, jit_pc);
if (jit_elf != nullptr) {
debug_pc = jit_pc;
elf = jit_elf;
}
}
// Copy all the things we need into the frame for symbolization.
frame.rel_pc = relative_pc;
frame.pc = pc - pc_adjustment;
frame.map_name = map_info->name;
frame.map_elf_start_offset = map_info->elf_start_offset;
frame.map_exact_offset = map_info->offset;
frame.map_start = map_info->start;
frame.map_end = map_info->end;
frame.map_flags = map_info->flags;
frame.map_load_bias = elf->GetLoadBias();
if (!elf->GetFunctionName(relative_pc, &frame.function_name, &frame.function_offset)) {
frame.function_name = "";
frame.function_offset = 0;
}
return frame;
}
constexpr size_t kMaxTraceLength = gwp_asan::AllocationMetadata::kMaxTraceLengthToCollect;
bool GwpAsanCrashData::HasDeallocationTrace() const {
@ -237,7 +183,8 @@ void GwpAsanCrashData::DumpDeallocationTrace(log_t* log, unwindstack::Unwinder*
unwinder->SetDisplayBuildID(true);
for (size_t i = 0; i < num_frames; ++i) {
unwindstack::FrameData frame_data = BuildFrame(unwinder, frames.get()[i], i);
unwindstack::FrameData frame_data = unwinder->BuildFrameFromPcOnly(frames.get()[i]);
frame_data.num = i;
_LOG(log, logtype::BACKTRACE, " %s\n", unwinder->FormatFrame(frame_data).c_str());
}
}
@ -263,7 +210,8 @@ void GwpAsanCrashData::DumpAllocationTrace(log_t* log, unwindstack::Unwinder* un
unwinder->SetDisplayBuildID(true);
for (size_t i = 0; i < num_frames; ++i) {
unwindstack::FrameData frame_data = BuildFrame(unwinder, frames.get()[i], i);
unwindstack::FrameData frame_data = unwinder->BuildFrameFromPcOnly(frames.get()[i]);
frame_data.num = i;
_LOG(log, logtype::BACKTRACE, " %s\n", unwinder->FormatFrame(frame_data).c_str());
}
}

50
libunwindstack/Unwinder.cpp
View file

@ -395,4 +395,54 @@ bool UnwinderFromPid::Init(ArchEnum arch) {
return true;
}
FrameData Unwinder::BuildFrameFromPcOnly(uint64_t pc) {
FrameData frame;
Maps* maps = GetMaps();
MapInfo* map_info = maps->Find(pc);
if (!map_info) {
frame.rel_pc = pc;
return frame;
}
ArchEnum arch = Regs::CurrentArch();
Elf* elf = map_info->GetElf(GetProcessMemory(), arch);
uint64_t relative_pc = elf->GetRelPc(pc, map_info);
uint64_t pc_adjustment = GetPcAdjustment(relative_pc, elf, arch);
relative_pc -= pc_adjustment;
// The debug PC may be different if the PC comes from the JIT.
uint64_t debug_pc = relative_pc;
// If we don't have a valid ELF file, check the JIT.
if (!elf->valid()) {
JitDebug jit_debug(GetProcessMemory());
uint64_t jit_pc = pc - pc_adjustment;
Elf* jit_elf = jit_debug.GetElf(maps, jit_pc);
if (jit_elf != nullptr) {
debug_pc = jit_pc;
elf = jit_elf;
}
}
// Copy all the things we need into the frame for symbolization.
frame.rel_pc = relative_pc;
frame.pc = pc - pc_adjustment;
frame.map_name = map_info->name;
frame.map_elf_start_offset = map_info->elf_start_offset;
frame.map_exact_offset = map_info->offset;
frame.map_start = map_info->start;
frame.map_end = map_info->end;
frame.map_flags = map_info->flags;
frame.map_load_bias = elf->GetLoadBias();
if (!resolve_names_ ||
!elf->GetFunctionName(relative_pc, &frame.function_name, &frame.function_offset)) {
frame.function_name = "";
frame.function_offset = 0;
}
return frame;
}
} // namespace unwindstack

7
libunwindstack/include/unwindstack/Unwinder.h
View file

@ -114,6 +114,13 @@ class Unwinder {
ErrorCode LastErrorCode() { return last_error_.code; }
uint64_t LastErrorAddress() { return last_error_.address; }
// Builds a frame for symbolization using the maps from this unwinder. The
// constructed frame contains just enough information to be used to symbolize
// frames collected by frame-pointer unwinding that's done outside of
// libunwindstack. This is used by tombstoned to symbolize frame pointer-based
// stack traces that are collected by tools such as GWP-ASan and MTE.
FrameData BuildFrameFromPcOnly(uint64_t pc);
protected:
Unwinder(size_t max_frames) : max_frames_(max_frames) { frames_.reserve(max_frames); }