Merge "libbacktrace_offline: support .ARM.exidx." (76977937) · Commits · e / os / android_system_core

libbacktrace/Android.bp

+14 −1

Original line number	Diff line number	Diff line
		@@ -117,4 +117,17 @@ cc_library_shared {
		},
		cflags: ["-O0"],
		srcs: ["backtrace_testlib.c"],

		target: {
		linux: {
		shared_libs: [
		"libunwind",
		],
		},
		android: {
		shared_libs: [
		"libunwind",
		],
		},
		}
		}
		No newline at end of file

libbacktrace/Android.mk

+0 −2

Original line number	Diff line number	Diff line
		@@ -111,8 +111,6 @@ backtrace_test_static_libraries_host := \
		backtrace_test_ldlibs_host += \
		-ldl \

		backtrace_test_strip_module := false

		module := backtrace_test
		module_tag := debug
		build_type := target

libbacktrace/BacktraceOffline.cpp

+214 −113

Original line number	Diff line number	Diff line
		@@ -50,6 +50,48 @@ extern "C" {

		#include "BacktraceLog.h"

		struct EhFrame {
		uint64_t hdr_vaddr;
		uint64_t vaddr;
		uint64_t fde_table_offset;
		uintptr_t min_func_vaddr;
		std::vector<uint8_t> hdr_data;
		std::vector<uint8_t> data;
		};

		struct ArmIdxEntry {
		uint32_t func_offset;
		uint32_t value;
		};

		struct ArmExidx {
		uint64_t exidx_vaddr;
		uint64_t extab_vaddr;
		std::vector<ArmIdxEntry> exidx_data;
		std::vector<uint8_t> extab_data;
		// There is a one-to-one map from exidx_data.func_offset to func_vaddr_array.
		std::vector<uint32_t> func_vaddr_array;
		};

		struct DebugFrameInfo {
		bool has_arm_exidx;
		bool has_eh_frame;
		bool has_debug_frame;
		bool has_gnu_debugdata;

		EhFrame eh_frame;
		ArmExidx arm_exidx;

		uint64_t min_vaddr;
		uint64_t text_end_vaddr;

		DebugFrameInfo() : has_arm_exidx(false), has_eh_frame(false),
		has_debug_frame(false), has_gnu_debugdata(false) { }
		};

		static std::unordered_map<std::string, std::unique_ptr<DebugFrameInfo>>& g_debug_frames =
		*new std::unordered_map<std::string, std::unique_ptr<DebugFrameInfo>>;

		void Space::Clear() {
		start = 0;
		end = 0;
		@@ -207,21 +249,16 @@ size_t BacktraceOffline::Read(uintptr_t addr, uint8_t* buffer, size_t bytes) {
		if (read_size != 0) {
		return read_size;
		}
		read_size = stack_space_.Read(addr, buffer, bytes);
		read_size = arm_exidx_space_.Read(addr, buffer, bytes);
		if (read_size != 0) {
		return read_size;
		}

		static bool FileOffsetToVaddr(
		const std::vector<DebugFrameInfo::EhFrame::ProgramHeader>& program_headers,
		uint64_t file_offset, uint64_t* vaddr) {
		for (auto& header : program_headers) {
		if (file_offset >= header.file_offset && file_offset < header.file_offset + header.file_size) {
		// TODO: Consider load_bias?
		*vaddr = file_offset - header.file_offset + header.vaddr;
		return true;
		}
		read_size = arm_extab_space_.Read(addr, buffer, bytes);
		if (read_size != 0) {
		return read_size;
		}
		return false;
		read_size = stack_space_.Read(addr, buffer, bytes);
		return read_size;
		}

		bool BacktraceOffline::FindProcInfo(unw_addr_space_t addr_space, uint64_t ip,
		@@ -236,22 +273,59 @@ bool BacktraceOffline::FindProcInfo(unw_addr_space_t addr_space, uint64_t ip,
		if (debug_frame == nullptr) {
		return false;
		}
		if (debug_frame->is_eh_frame) {
		uint64_t ip_offset = ip - map.start + map.offset;
		uint64_t ip_vaddr; // vaddr in the elf file.
		bool result = FileOffsetToVaddr(debug_frame->eh_frame.program_headers, ip_offset, &ip_vaddr);
		if (!result) {
		return false;

		eh_frame_hdr_space_.Clear();
		eh_frame_space_.Clear();
		arm_exidx_space_.Clear();
		arm_extab_space_.Clear();

		// vaddr in the elf file.
		uint64_t ip_vaddr = ip - map.start + debug_frame->min_vaddr;
		if (debug_frame->has_arm_exidx) {
		auto& func_vaddrs = debug_frame->arm_exidx.func_vaddr_array;
		if (ip_vaddr >= func_vaddrs[0] && ip_vaddr < debug_frame->text_end_vaddr) {
		// Use binary search to find the correct function.
		auto it = std::upper_bound(func_vaddrs.begin(), func_vaddrs.end(),
		static_cast<uint32_t>(ip_vaddr));
		if (it != func_vaddrs.begin()) {
		--it;
		// Found the exidx entry.
		size_t index = it - func_vaddrs.begin();

		proc_info->format = UNW_INFO_FORMAT_ARM_EXIDX;
		proc_info->unwind_info = reinterpret_cast<void*>(
		static_cast<uintptr_t>(index * sizeof(ArmIdxEntry) +
		debug_frame->arm_exidx.exidx_vaddr +
		debug_frame->min_vaddr));

		// Prepare arm_exidx space and arm_extab space.
		arm_exidx_space_.start = debug_frame->min_vaddr + debug_frame->arm_exidx.exidx_vaddr;
		arm_exidx_space_.end = arm_exidx_space_.start +
		debug_frame->arm_exidx.exidx_data.size() * sizeof(ArmIdxEntry);
		arm_exidx_space_.data = reinterpret_cast<const uint8_t*>(
		debug_frame->arm_exidx.exidx_data.data());

		arm_extab_space_.start = debug_frame->min_vaddr + debug_frame->arm_exidx.extab_vaddr;
		arm_extab_space_.end = arm_extab_space_.start +
		debug_frame->arm_exidx.extab_data.size();
		arm_extab_space_.data = debug_frame->arm_exidx.extab_data.data();
		return true;
		}
		}
		}
		// Calculate the addresses where .eh_frame_hdr and .eh_frame stay when the process was running.
		eh_frame_hdr_space_.start = (ip - ip_vaddr) + debug_frame->eh_frame.eh_frame_hdr_vaddr;

		if (debug_frame->has_eh_frame) {
		if (ip_vaddr >= debug_frame->eh_frame.min_func_vaddr &&
		ip_vaddr < debug_frame->text_end_vaddr) {
		// Prepare eh_frame_hdr space and eh_frame space.
		eh_frame_hdr_space_.start = ip - ip_vaddr + debug_frame->eh_frame.hdr_vaddr;
		eh_frame_hdr_space_.end =
		eh_frame_hdr_space_.start + debug_frame->eh_frame.eh_frame_hdr_data.size();
		eh_frame_hdr_space_.data = debug_frame->eh_frame.eh_frame_hdr_data.data();
		eh_frame_hdr_space_.start + debug_frame->eh_frame.hdr_data.size();
		eh_frame_hdr_space_.data = debug_frame->eh_frame.hdr_data.data();

		eh_frame_space_.start = (ip - ip_vaddr) + debug_frame->eh_frame.eh_frame_vaddr;
		eh_frame_space_.end = eh_frame_space_.start + debug_frame->eh_frame.eh_frame_data.size();
		eh_frame_space_.data = debug_frame->eh_frame.eh_frame_data.data();
		eh_frame_space_.start = ip - ip_vaddr + debug_frame->eh_frame.vaddr;
		eh_frame_space_.end = eh_frame_space_.start + debug_frame->eh_frame.data.size();
		eh_frame_space_.data = debug_frame->eh_frame.data.data();

		unw_dyn_info di;
		memset(&di, '\0', sizeof(di));
		@@ -261,20 +335,28 @@ bool BacktraceOffline::FindProcInfo(unw_addr_space_t addr_space, uint64_t ip,
		di.u.rti.name_ptr = 0;
		di.u.rti.segbase = eh_frame_hdr_space_.start;
		di.u.rti.table_data =
		eh_frame_hdr_space_.start + debug_frame->eh_frame.fde_table_offset_in_eh_frame_hdr;
		eh_frame_hdr_space_.start + debug_frame->eh_frame.fde_table_offset;
		di.u.rti.table_len = (eh_frame_hdr_space_.end - di.u.rti.table_data) / sizeof(unw_word_t);
		// TODO: Do it ourselves is more efficient than calling this function.
		int ret = dwarf_search_unwind_table(addr_space, ip, &di, proc_info, need_unwind_info, this);
		return ret == 0;
		if (ret == 0) {
		return true;
		}
		}
		}

		eh_frame_hdr_space_.Clear();
		eh_frame_space_.Clear();
		if (debug_frame->has_debug_frame \|\| debug_frame->has_gnu_debugdata) {
		unw_dyn_info_t di;
		unw_word_t segbase = map.start - map.offset;
		// TODO: http://b/32916571
		// TODO: Do it ourselves is more efficient than calling libunwind functions.
		int found = dwarf_find_debug_frame(0, &di, ip, segbase, filename.c_str(), map.start, map.end);
		if (found == 1) {
		int ret = dwarf_search_unwind_table(addr_space, ip, &di, proc_info, need_unwind_info, this);
		return ret == 0;
		if (ret == 0) {
		return true;
		}
		}
		}
		return false;
		}
		@@ -462,33 +544,18 @@ std::string BacktraceOffline::GetFunctionNameRaw(uintptr_t, uintptr_t* offset) {
		return "";
		}

		std::unordered_map<std::string, std::unique_ptr<DebugFrameInfo>> BacktraceOffline::debug_frames_;
		std::unordered_set<std::string> BacktraceOffline::debug_frame_missing_files_;

		static DebugFrameInfo* ReadDebugFrameFromFile(const std::string& filename);

		DebugFrameInfo* BacktraceOffline::GetDebugFrameInFile(const std::string& filename) {
		if (cache_file_) {
		auto it = debug_frames_.find(filename);
		if (it != debug_frames_.end()) {
		auto it = g_debug_frames.find(filename);
		if (it != g_debug_frames.end()) {
		return it->second.get();
		}
		if (debug_frame_missing_files_.find(filename) != debug_frame_missing_files_.end()) {
		return nullptr;
		}
		}
		DebugFrameInfo* debug_frame = ReadDebugFrameFromFile(filename);
		if (cache_file_) {
		if (debug_frame != nullptr) {
		debug_frames_.emplace(filename, std::unique_ptr<DebugFrameInfo>(debug_frame));
		} else {
		debug_frame_missing_files_.insert(filename);
		}
		} else {
		if (last_debug_frame_ != nullptr) {
		delete last_debug_frame_;
		}
		last_debug_frame_ = debug_frame;
		g_debug_frames.emplace(filename, std::unique_ptr<DebugFrameInfo>(debug_frame));
		}
		return debug_frame;
		}
		@@ -556,72 +623,106 @@ static bool GetFdeTableOffsetInEhFrameHdr(const std::vector<uint8_t>& data,
		return true;
		}

		using ProgramHeader = DebugFrameInfo::EhFrame::ProgramHeader;

		template <class ELFT>
		DebugFrameInfo* ReadDebugFrameFromELFFile(const llvm::object::ELFFile<ELFT>* elf) {
		DebugFrameInfo* result = new DebugFrameInfo;
		result->text_end_vaddr = std::numeric_limits<uint64_t>::max();

		bool has_eh_frame_hdr = false;
		uint64_t eh_frame_hdr_vaddr = 0;
		std::vector<uint8_t> eh_frame_hdr_data;
		bool has_eh_frame = false;
		uint64_t eh_frame_vaddr = 0;
		std::vector<uint8_t> eh_frame_data;

		for (auto it = elf->section_begin(); it != elf->section_end(); ++it) {
		llvm::ErrorOr<llvm::StringRef> name = elf->getSectionName(&*it);
		if (name) {
		if (name.get() == ".debug_frame") {
		DebugFrameInfo* debug_frame = new DebugFrameInfo;
		debug_frame->is_eh_frame = false;
		return debug_frame;
		}
		if (name.get() == ".eh_frame_hdr") {
		has_eh_frame_hdr = true;
		eh_frame_hdr_vaddr = it->sh_addr;
		std::string s = name.get();
		if (s == ".debug_frame") {
		result->has_debug_frame = true;
		} else if (s == ".gnu_debugdata") {
		result->has_gnu_debugdata = true;
		} else if (s == ".eh_frame_hdr") {
		result->eh_frame.hdr_vaddr = it->sh_addr;
		llvm::ErrorOr<llvm::ArrayRef<uint8_t>> data = elf->getSectionContents(&*it);
		if (data) {
		eh_frame_hdr_data.insert(eh_frame_hdr_data.begin(), data->data(),
		data->data() + data->size());
		} else {
		return nullptr;
		result->eh_frame.hdr_data.insert(result->eh_frame.hdr_data.end(),
		data->data(), data->data() + data->size());

		uint64_t fde_table_offset;
		if (GetFdeTableOffsetInEhFrameHdr(result->eh_frame.hdr_data,
		&fde_table_offset)) {
		result->eh_frame.fde_table_offset = fde_table_offset;
		// Make sure we have at least one entry in fde_table.
		if (fde_table_offset + 2 * sizeof(int32_t) <= data->size()) {
		intptr_t eh_frame_hdr_vaddr = it->sh_addr;
		int32_t sdata;
		uint8_t* p = result->eh_frame.hdr_data.data() + fde_table_offset;
		memcpy(&sdata, p, sizeof(sdata));
		result->eh_frame.min_func_vaddr = eh_frame_hdr_vaddr + sdata;
		has_eh_frame_hdr = true;
		}
		} else if (name.get() == ".eh_frame") {
		has_eh_frame = true;
		eh_frame_vaddr = it->sh_addr;
		}
		}
		} else if (s == ".eh_frame") {
		result->eh_frame.vaddr = it->sh_addr;
		llvm::ErrorOr<llvm::ArrayRef<uint8_t>> data = elf->getSectionContents(&*it);
		if (data) {
		eh_frame_data.insert(eh_frame_data.begin(), data->data(), data->data() + data->size());
		} else {
		return nullptr;
		result->eh_frame.data.insert(result->eh_frame.data.end(),
		data->data(), data->data() + data->size());
		has_eh_frame = true;
		}
		} else if (s == ".ARM.exidx") {
		result->arm_exidx.exidx_vaddr = it->sh_addr;
		llvm::ErrorOr<llvm::ArrayRef<uint8_t>> data = elf->getSectionContents(&*it);
		if (data) {
		size_t entry_count = data->size() / sizeof(ArmIdxEntry);
		result->arm_exidx.exidx_data.resize(entry_count);
		memcpy(result->arm_exidx.exidx_data.data(), data->data(),
		entry_count * sizeof(ArmIdxEntry));
		if (entry_count > 0u) {
		// Change IdxEntry.func_offset into vaddr.
		result->arm_exidx.func_vaddr_array.reserve(entry_count);
		uint32_t vaddr = it->sh_addr;
		for (auto& entry : result->arm_exidx.exidx_data) {
		uint32_t func_offset = entry.func_offset + vaddr;
		// Clear bit 31 for the prel31 offset.
		// Arm sets bit 0 to mark it as thumb code, remove the flag.
		result->arm_exidx.func_vaddr_array.push_back(
		func_offset & 0x7ffffffe);
		vaddr += 8;
		}
		result->has_arm_exidx = true;
		}
		}
		} else if (s == ".ARM.extab") {
		result->arm_exidx.extab_vaddr = it->sh_addr;
		llvm::ErrorOr<llvm::ArrayRef<uint8_t>> data = elf->getSectionContents(&*it);
		if (data) {
		result->arm_exidx.extab_data.insert(result->arm_exidx.extab_data.end(),
		data->data(), data->data() + data->size());
		}
		} else if (s == ".text") {
		result->text_end_vaddr = it->sh_addr + it->sh_size;
		}
		}
		if (!(has_eh_frame_hdr && has_eh_frame)) {
		return nullptr;
		}
		uint64_t fde_table_offset;
		if (!GetFdeTableOffsetInEhFrameHdr(eh_frame_hdr_data, &fde_table_offset)) {
		return nullptr;

		if (has_eh_frame_hdr && has_eh_frame) {
		result->has_eh_frame = true;
		}

		std::vector<ProgramHeader> program_headers;
		result->min_vaddr = std::numeric_limits<uint64_t>::max();
		for (auto it = elf->program_header_begin(); it != elf->program_header_end(); ++it) {
		ProgramHeader header;
		header.vaddr = it->p_vaddr;
		header.file_offset = it->p_offset;
		header.file_size = it->p_filesz;
		program_headers.push_back(header);
		}
		DebugFrameInfo* debug_frame = new DebugFrameInfo;
		debug_frame->is_eh_frame = true;
		debug_frame->eh_frame.eh_frame_hdr_vaddr = eh_frame_hdr_vaddr;
		debug_frame->eh_frame.eh_frame_vaddr = eh_frame_vaddr;
		debug_frame->eh_frame.fde_table_offset_in_eh_frame_hdr = fde_table_offset;
		debug_frame->eh_frame.eh_frame_hdr_data = std::move(eh_frame_hdr_data);
		debug_frame->eh_frame.eh_frame_data = std::move(eh_frame_data);
		debug_frame->eh_frame.program_headers = program_headers;
		return debug_frame;
		if ((it->p_type == llvm::ELF::PT_LOAD) && (it->p_flags & llvm::ELF::PF_X)) {
		if (it->p_vaddr < result->min_vaddr) {
		result->min_vaddr = it->p_vaddr;
		}
		}
		}
		if (!result->has_eh_frame && !result->has_arm_exidx && !result->has_debug_frame &&
		!result->has_gnu_debugdata) {
		delete result;
		return nullptr;
		}
		return result;
		}

		static bool IsValidElfPath(const std::string& filename) {

libbacktrace/BacktraceOffline.h

+5 −27

Original line number	Diff line number	Diff line
		@@ -40,22 +40,7 @@ struct Space {
		size_t Read(uint64_t addr, uint8_t* buffer, size_t size);
		};

		struct DebugFrameInfo {
		bool is_eh_frame;
		struct EhFrame {
		uint64_t eh_frame_hdr_vaddr;
		uint64_t eh_frame_vaddr;
		uint64_t fde_table_offset_in_eh_frame_hdr;
		std::vector<uint8_t> eh_frame_hdr_data;
		std::vector<uint8_t> eh_frame_data;
		struct ProgramHeader {
		uint64_t vaddr;
		uint64_t file_offset;
		uint64_t file_size;
		};
		std::vector<ProgramHeader> program_headers;
		} eh_frame;
		};
		struct DebugFrameInfo;

		class BacktraceOffline : public Backtrace {
		public:
		@@ -63,18 +48,13 @@ class BacktraceOffline : public Backtrace {
		bool cache_file)
		: Backtrace(pid, tid, map),
		cache_file_(cache_file),
		context_(nullptr),
		last_debug_frame_(nullptr) {
		context_(nullptr) {
		stack_space_.start = stack.start;
		stack_space_.end = stack.end;
		stack_space_.data = stack.data;
		}

		virtual ~BacktraceOffline() {
		if (last_debug_frame_ != nullptr) {
		delete last_debug_frame_;
		}
		}
		virtual ~BacktraceOffline() = default;

		bool Unwind(size_t num_ignore_frames, ucontext_t* context) override;

		@@ -91,15 +71,13 @@ class BacktraceOffline : public Backtrace {
		std::string GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) override;
		DebugFrameInfo* GetDebugFrameInFile(const std::string& filename);

		static std::unordered_map<std::string, std::unique_ptr<DebugFrameInfo>> debug_frames_;
		static std::unordered_set<std::string> debug_frame_missing_files_;

		bool cache_file_;
		ucontext_t* context_;
		Space eh_frame_hdr_space_;
		Space eh_frame_space_;
		Space arm_extab_space_;
		Space arm_exidx_space_;
		Space stack_space_;
		DebugFrameInfo* last_debug_frame_;
		};

		#endif // _LIBBACKTRACE_BACKTRACE_OFFLINE_H