Revert "Revert "Add BacktraceOffline for offline backtracing.""
This reverts commit ab5e583327e4dfd9f7c38ab6ed4c4714508ce544.
And statically link llvm libraries on host to remove dependency
on 32-bit llvm shared library which is not included in the prebuilt.
Bug: 22229391
Change-Id: I8210687655ee1809fd820ab2a6ca5dfaf3f9096d
diff --git a/debuggerd/Android.mk b/debuggerd/Android.mk
index f7a5f82..de0f943 100644
--- a/debuggerd/Android.mk
+++ b/debuggerd/Android.mk
@@ -99,6 +99,7 @@
debuggerd_cpp_flags := \
$(common_cppflags) \
-Wno-missing-field-initializers \
+ -fno-rtti \
# Only build the host tests on linux.
ifeq ($(HOST_OS),linux)
diff --git a/include/backtrace/Backtrace.h b/include/backtrace/Backtrace.h
index 290682a..f440bd2 100644
--- a/include/backtrace/Backtrace.h
+++ b/include/backtrace/Backtrace.h
@@ -52,6 +52,12 @@
typedef ucontext ucontext_t;
#endif
+struct backtrace_stackinfo_t {
+ uint64_t start;
+ uint64_t end;
+ const uint8_t* data;
+};
+
class Backtrace {
public:
// Create the correct Backtrace object based on what is to be unwound.
@@ -66,6 +72,14 @@
// If map is not NULL, the map is still owned by the caller.
static Backtrace* Create(pid_t pid, pid_t tid, BacktraceMap* map = NULL);
+ // Create an offline Backtrace object that can be used to do an unwind without a process
+ // that is still running. If cache_file is set to true, then elf information will be cached
+ // for this call. The cached information survives until the calling process ends. This means
+ // that subsequent calls to create offline Backtrace objects will continue to use the same
+ // cache. It also assumes that the elf files used for each offline unwind are the same.
+ static Backtrace* CreateOffline(pid_t pid, pid_t tid, BacktraceMap* map,
+ const backtrace_stackinfo_t& stack, bool cache_file = false);
+
virtual ~Backtrace();
// Get the current stack trace and store in the backtrace_ structure.
diff --git a/include/backtrace/BacktraceMap.h b/include/backtrace/BacktraceMap.h
index bb18aa2..2373c45 100644
--- a/include/backtrace/BacktraceMap.h
+++ b/include/backtrace/BacktraceMap.h
@@ -31,6 +31,7 @@
#include <deque>
#include <string>
+#include <vector>
struct backtrace_map_t {
uintptr_t start = 0;
@@ -48,6 +49,8 @@
// is unsupported.
static BacktraceMap* Create(pid_t pid, bool uncached = false);
+ static BacktraceMap* Create(pid_t pid, const std::vector<backtrace_map_t>& maps);
+
virtual ~BacktraceMap();
// Fill in the map data structure for the given address.
diff --git a/libbacktrace/Android.build.mk b/libbacktrace/Android.build.mk
index 4983b55..8e63dab 100644
--- a/libbacktrace/Android.build.mk
+++ b/libbacktrace/Android.build.mk
@@ -69,7 +69,10 @@
$($(module)_ldlibs) \
$($(module)_ldlibs_$(build_type)) \
+LOCAL_STRIP_MODULE := $($(module)_strip_module)
+
ifeq ($(build_type),target)
+ include $(LLVM_DEVICE_BUILD_MK)
include $(BUILD_$(build_target))
endif
@@ -77,6 +80,7 @@
# Only build if host builds are supported.
ifeq ($(build_host),true)
LOCAL_CFLAGS += -Wno-extern-c-compat -fno-omit-frame-pointer
+ include $(LLVM_HOST_BUILD_MK)
include $(BUILD_HOST_$(build_target))
endif
endif
diff --git a/libbacktrace/Android.mk b/libbacktrace/Android.mk
index 395d677..9c6742e 100644
--- a/libbacktrace/Android.mk
+++ b/libbacktrace/Android.mk
@@ -25,6 +25,7 @@
libbacktrace_common_cppflags := \
-std=gnu++11 \
+ -I external/libunwind/include/tdep \
# The latest clang (r230699) does not allow SP/PC to be declared in inline asm lists.
libbacktrace_common_clang_cflags += \
@@ -37,6 +38,9 @@
endif
endif
+LLVM_ROOT_PATH := external/llvm
+include $(LLVM_ROOT_PATH)/llvm.mk
+
#-------------------------------------------------------------------------
# The libbacktrace library.
#-------------------------------------------------------------------------
@@ -44,6 +48,7 @@
Backtrace.cpp \
BacktraceCurrent.cpp \
BacktraceMap.cpp \
+ BacktraceOffline.cpp \
BacktracePtrace.cpp \
thread_utils.c \
ThreadEntry.cpp \
@@ -56,6 +61,20 @@
liblog \
libunwind \
+# Use shared llvm library on device to save space.
+libbacktrace_shared_libraries_target := \
+ libLLVM \
+
+# Use static llvm libraries on host to remove dependency on 32-bit llvm shared library
+# which is not included in the prebuilt.
+libbacktrace_static_libraries_host := \
+ libLLVMObject \
+ libLLVMBitReader \
+ libLLVMMC \
+ libLLVMMCParser \
+ libLLVMCore \
+ libLLVMSupport \
+
libbacktrace_ldlibs_host := \
-lpthread \
-lrt \
@@ -86,6 +105,8 @@
libbacktrace_test_src_files := \
backtrace_testlib.c \
+libbacktrace_test_strip_module := false
+
module := libbacktrace_test
module_tag := debug
build_type := target
@@ -107,6 +128,7 @@
-DENABLE_PSS_TESTS \
backtrace_test_src_files := \
+ backtrace_offline_test.cpp \
backtrace_test.cpp \
GetPss.cpp \
thread_utils.c \
@@ -120,6 +142,7 @@
libbacktrace \
libbase \
libcutils \
+ libunwind \
backtrace_test_shared_libraries_target += \
libdl \
@@ -127,6 +150,8 @@
backtrace_test_ldlibs_host += \
-ldl \
+backtrace_test_strip_module := false
+
module := backtrace_test
module_tag := debug
build_type := target
diff --git a/libbacktrace/Backtrace.cpp b/libbacktrace/Backtrace.cpp
index 97f0ef4..9ead452 100644
--- a/libbacktrace/Backtrace.cpp
+++ b/libbacktrace/Backtrace.cpp
@@ -30,6 +30,7 @@
#include <cutils/threads.h>
#include "BacktraceLog.h"
+#include "BacktraceOffline.h"
#include "thread_utils.h"
#include "UnwindCurrent.h"
#include "UnwindPtrace.h"
@@ -140,3 +141,8 @@
return new UnwindPtrace(pid, tid, map);
}
}
+
+Backtrace* Backtrace::CreateOffline(pid_t pid, pid_t tid, BacktraceMap* map,
+ const backtrace_stackinfo_t& stack, bool cache_file) {
+ return new BacktraceOffline(pid, tid, map, stack, cache_file);
+}
diff --git a/libbacktrace/BacktraceMap.cpp b/libbacktrace/BacktraceMap.cpp
index ca47f67..eac20fe 100644
--- a/libbacktrace/BacktraceMap.cpp
+++ b/libbacktrace/BacktraceMap.cpp
@@ -144,3 +144,13 @@
return map;
}
#endif
+
+BacktraceMap* BacktraceMap::Create(pid_t pid, const std::vector<backtrace_map_t>& maps) {
+ BacktraceMap* backtrace_map = new BacktraceMap(pid);
+ backtrace_map->maps_.insert(backtrace_map->maps_.begin(), maps.begin(), maps.end());
+ std::sort(backtrace_map->maps_.begin(), backtrace_map->maps_.end(),
+ [](const backtrace_map_t& map1, const backtrace_map_t& map2) {
+ return map1.start < map2.start;
+ });
+ return backtrace_map;
+}
diff --git a/libbacktrace/BacktraceOffline.cpp b/libbacktrace/BacktraceOffline.cpp
new file mode 100644
index 0000000..27dfb83
--- /dev/null
+++ b/libbacktrace/BacktraceOffline.cpp
@@ -0,0 +1,636 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "BacktraceOffline.h"
+
+extern "C" {
+#define UNW_REMOTE_ONLY
+#include <dwarf.h>
+}
+
+#include <stdint.h>
+#include <string.h>
+#include <sys/types.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include <backtrace/Backtrace.h>
+#include <backtrace/BacktraceMap.h>
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-parameter"
+
+#include <llvm/ADT/StringRef.h>
+#include <llvm/Object/Binary.h>
+#include <llvm/Object/ELFObjectFile.h>
+#include <llvm/Object/ObjectFile.h>
+
+#pragma clang diagnostic pop
+
+#include "BacktraceLog.h"
+
+void Space::Clear() {
+ start = 0;
+ end = 0;
+ data = nullptr;
+}
+
+size_t Space::Read(uint64_t addr, uint8_t* buffer, size_t size) {
+ if (addr >= start && addr < end) {
+ size_t read_size = std::min(size, static_cast<size_t>(end - addr));
+ memcpy(buffer, data + (addr - start), read_size);
+ return read_size;
+ }
+ return 0;
+}
+
+static int FindProcInfo(unw_addr_space_t addr_space, unw_word_t ip, unw_proc_info* proc_info,
+ int need_unwind_info, void* arg) {
+ BacktraceOffline* backtrace = reinterpret_cast<BacktraceOffline*>(arg);
+ bool result = backtrace->FindProcInfo(addr_space, ip, proc_info, need_unwind_info);
+ return result ? 0 : -UNW_EINVAL;
+}
+
+static void PutUnwindInfo(unw_addr_space_t, unw_proc_info_t*, void*) {
+}
+
+static int GetDynInfoListAddr(unw_addr_space_t, unw_word_t*, void*) {
+ return -UNW_ENOINFO;
+}
+
+static int AccessMem(unw_addr_space_t, unw_word_t addr, unw_word_t* value, int write, void* arg) {
+ if (write == 1) {
+ return -UNW_EINVAL;
+ }
+ BacktraceOffline* backtrace = reinterpret_cast<BacktraceOffline*>(arg);
+ *value = 0;
+ size_t read_size = backtrace->Read(addr, reinterpret_cast<uint8_t*>(value), sizeof(unw_word_t));
+ // Strictly we should check if read_size matches sizeof(unw_word_t), but it is possible in
+ // .eh_frame_hdr that the section can end at a position not aligned in sizeof(unw_word_t), and
+ // we should permit the read at the end of the section.
+ return (read_size > 0u ? 0 : -UNW_EINVAL);
+}
+
+static int AccessReg(unw_addr_space_t, unw_regnum_t unwind_reg, unw_word_t* value, int write,
+ void* arg) {
+ if (write == 1) {
+ return -UNW_EINVAL;
+ }
+ BacktraceOffline* backtrace = reinterpret_cast<BacktraceOffline*>(arg);
+ uint64_t reg_value;
+ bool result = backtrace->ReadReg(unwind_reg, ®_value);
+ if (result) {
+ *value = static_cast<unw_word_t>(reg_value);
+ }
+ return result ? 0 : -UNW_EINVAL;
+}
+
+static int AccessFpReg(unw_addr_space_t, unw_regnum_t, unw_fpreg_t*, int, void*) {
+ return -UNW_EINVAL;
+}
+
+static int Resume(unw_addr_space_t, unw_cursor_t*, void*) {
+ return -UNW_EINVAL;
+}
+
+static int GetProcName(unw_addr_space_t, unw_word_t, char*, size_t, unw_word_t*, void*) {
+ return -UNW_EINVAL;
+}
+
+static unw_accessors_t accessors = {
+ .find_proc_info = FindProcInfo,
+ .put_unwind_info = PutUnwindInfo,
+ .get_dyn_info_list_addr = GetDynInfoListAddr,
+ .access_mem = AccessMem,
+ .access_reg = AccessReg,
+ .access_fpreg = AccessFpReg,
+ .resume = Resume,
+ .get_proc_name = GetProcName,
+};
+
+bool BacktraceOffline::Unwind(size_t num_ignore_frames, ucontext_t* context) {
+ if (context == nullptr) {
+ BACK_LOGW("The context is needed for offline backtracing.");
+ return false;
+ }
+ context_ = context;
+
+ unw_addr_space_t addr_space = unw_create_addr_space(&accessors, 0);
+ unw_cursor_t cursor;
+ int ret = unw_init_remote(&cursor, addr_space, this);
+ if (ret != 0) {
+ BACK_LOGW("unw_init_remote failed %d", ret);
+ unw_destroy_addr_space(addr_space);
+ return false;
+ }
+ size_t num_frames = 0;
+ do {
+ unw_word_t pc;
+ ret = unw_get_reg(&cursor, UNW_REG_IP, &pc);
+ if (ret < 0) {
+ BACK_LOGW("Failed to read IP %d", ret);
+ break;
+ }
+ unw_word_t sp;
+ ret = unw_get_reg(&cursor, UNW_REG_SP, &sp);
+ if (ret < 0) {
+ BACK_LOGW("Failed to read SP %d", ret);
+ break;
+ }
+
+ if (num_ignore_frames == 0) {
+ frames_.resize(num_frames + 1);
+ backtrace_frame_data_t* frame = &frames_[num_frames];
+ frame->num = num_frames;
+ frame->pc = static_cast<uintptr_t>(pc);
+ frame->sp = static_cast<uintptr_t>(sp);
+ frame->stack_size = 0;
+
+ if (num_frames > 0) {
+ backtrace_frame_data_t* prev = &frames_[num_frames - 1];
+ prev->stack_size = frame->sp - prev->sp;
+ }
+ frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
+ FillInMap(frame->pc, &frame->map);
+ num_frames++;
+ } else {
+ num_ignore_frames--;
+ }
+ ret = unw_step(&cursor);
+ } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
+
+ unw_destroy_addr_space(addr_space);
+ context_ = nullptr;
+ return true;
+}
+
+bool BacktraceOffline::ReadWord(uintptr_t ptr, word_t* out_value) {
+ size_t bytes_read = Read(ptr, reinterpret_cast<uint8_t*>(out_value), sizeof(word_t));
+ return bytes_read == sizeof(word_t);
+}
+
+size_t BacktraceOffline::Read(uintptr_t addr, uint8_t* buffer, size_t bytes) {
+ // Normally, libunwind needs stack information and call frame information to do remote unwinding.
+ // If call frame information is stored in .debug_frame, libunwind can read it from file
+ // by itself. If call frame information is stored in .eh_frame, we need to provide data in
+ // .eh_frame/.eh_frame_hdr sections.
+ // The order of readings below doesn't matter, as the spaces don't overlap with each other.
+ size_t read_size = eh_frame_hdr_space_.Read(addr, buffer, bytes);
+ if (read_size != 0) {
+ return read_size;
+ }
+ read_size = eh_frame_space_.Read(addr, buffer, bytes);
+ if (read_size != 0) {
+ return read_size;
+ }
+ read_size = stack_space_.Read(addr, buffer, bytes);
+ 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;
+ }
+ }
+ return false;
+}
+
+bool BacktraceOffline::FindProcInfo(unw_addr_space_t addr_space, uint64_t ip,
+ unw_proc_info_t* proc_info, int need_unwind_info) {
+ backtrace_map_t map;
+ FillInMap(ip, &map);
+ if (!BacktraceMap::IsValid(map)) {
+ return false;
+ }
+ const std::string& filename = map.name;
+ DebugFrameInfo* debug_frame = GetDebugFrameInFile(filename);
+ 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;
+ }
+ // 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;
+ 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_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();
+
+ unw_dyn_info di;
+ memset(&di, '\0', sizeof(di));
+ di.start_ip = map.start;
+ di.end_ip = map.end;
+ di.format = UNW_INFO_FORMAT_REMOTE_TABLE;
+ 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;
+ di.u.rti.table_len = (eh_frame_hdr_space_.end - di.u.rti.table_data) / sizeof(unw_word_t);
+ int ret = dwarf_search_unwind_table(addr_space, ip, &di, proc_info, need_unwind_info, this);
+ return ret == 0;
+ }
+
+ eh_frame_hdr_space_.Clear();
+ eh_frame_space_.Clear();
+ unw_dyn_info_t di;
+ unw_word_t segbase = map.start - map.offset;
+ 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;
+ }
+ return false;
+}
+
+bool BacktraceOffline::ReadReg(size_t reg, uint64_t* value) {
+ bool result = true;
+#if defined(__arm__)
+ switch (reg) {
+ case UNW_ARM_R0:
+ *value = context_->uc_mcontext.arm_r0;
+ break;
+ case UNW_ARM_R1:
+ *value = context_->uc_mcontext.arm_r1;
+ break;
+ case UNW_ARM_R2:
+ *value = context_->uc_mcontext.arm_r2;
+ break;
+ case UNW_ARM_R3:
+ *value = context_->uc_mcontext.arm_r3;
+ break;
+ case UNW_ARM_R4:
+ *value = context_->uc_mcontext.arm_r4;
+ break;
+ case UNW_ARM_R5:
+ *value = context_->uc_mcontext.arm_r5;
+ break;
+ case UNW_ARM_R6:
+ *value = context_->uc_mcontext.arm_r6;
+ break;
+ case UNW_ARM_R7:
+ *value = context_->uc_mcontext.arm_r7;
+ break;
+ case UNW_ARM_R8:
+ *value = context_->uc_mcontext.arm_r8;
+ break;
+ case UNW_ARM_R9:
+ *value = context_->uc_mcontext.arm_r9;
+ break;
+ case UNW_ARM_R10:
+ *value = context_->uc_mcontext.arm_r10;
+ break;
+ case UNW_ARM_R11:
+ *value = context_->uc_mcontext.arm_fp;
+ break;
+ case UNW_ARM_R12:
+ *value = context_->uc_mcontext.arm_ip;
+ break;
+ case UNW_ARM_R13:
+ *value = context_->uc_mcontext.arm_sp;
+ break;
+ case UNW_ARM_R14:
+ *value = context_->uc_mcontext.arm_lr;
+ break;
+ case UNW_ARM_R15:
+ *value = context_->uc_mcontext.arm_pc;
+ break;
+ default:
+ result = false;
+ }
+#elif defined(__aarch64__)
+ if (reg <= UNW_AARCH64_PC) {
+ *value = context_->uc_mcontext.regs[reg];
+ } else {
+ result = false;
+ }
+#elif defined(__x86_64__)
+ switch (reg) {
+ case UNW_X86_64_R8:
+ *value = context_->uc_mcontext.gregs[REG_R8];
+ break;
+ case UNW_X86_64_R9:
+ *value = context_->uc_mcontext.gregs[REG_R9];
+ break;
+ case UNW_X86_64_R10:
+ *value = context_->uc_mcontext.gregs[REG_R10];
+ break;
+ case UNW_X86_64_R11:
+ *value = context_->uc_mcontext.gregs[REG_R11];
+ break;
+ case UNW_X86_64_R12:
+ *value = context_->uc_mcontext.gregs[REG_R12];
+ break;
+ case UNW_X86_64_R13:
+ *value = context_->uc_mcontext.gregs[REG_R13];
+ break;
+ case UNW_X86_64_R14:
+ *value = context_->uc_mcontext.gregs[REG_R14];
+ break;
+ case UNW_X86_64_R15:
+ *value = context_->uc_mcontext.gregs[REG_R15];
+ break;
+ case UNW_X86_64_RDI:
+ *value = context_->uc_mcontext.gregs[REG_RDI];
+ break;
+ case UNW_X86_64_RSI:
+ *value = context_->uc_mcontext.gregs[REG_RSI];
+ break;
+ case UNW_X86_64_RBP:
+ *value = context_->uc_mcontext.gregs[REG_RBP];
+ break;
+ case UNW_X86_64_RBX:
+ *value = context_->uc_mcontext.gregs[REG_RBX];
+ break;
+ case UNW_X86_64_RDX:
+ *value = context_->uc_mcontext.gregs[REG_RDX];
+ break;
+ case UNW_X86_64_RAX:
+ *value = context_->uc_mcontext.gregs[REG_RAX];
+ break;
+ case UNW_X86_64_RCX:
+ *value = context_->uc_mcontext.gregs[REG_RCX];
+ break;
+ case UNW_X86_64_RSP:
+ *value = context_->uc_mcontext.gregs[REG_RSP];
+ break;
+ case UNW_X86_64_RIP:
+ *value = context_->uc_mcontext.gregs[REG_RIP];
+ break;
+ default:
+ result = false;
+ }
+#elif defined(__i386__)
+ switch (reg) {
+ case UNW_X86_GS:
+ *value = context_->uc_mcontext.gregs[REG_GS];
+ break;
+ case UNW_X86_FS:
+ *value = context_->uc_mcontext.gregs[REG_FS];
+ break;
+ case UNW_X86_ES:
+ *value = context_->uc_mcontext.gregs[REG_ES];
+ break;
+ case UNW_X86_DS:
+ *value = context_->uc_mcontext.gregs[REG_DS];
+ break;
+ case UNW_X86_EAX:
+ *value = context_->uc_mcontext.gregs[REG_EAX];
+ break;
+ case UNW_X86_EBX:
+ *value = context_->uc_mcontext.gregs[REG_EBX];
+ break;
+ case UNW_X86_ECX:
+ *value = context_->uc_mcontext.gregs[REG_ECX];
+ break;
+ case UNW_X86_EDX:
+ *value = context_->uc_mcontext.gregs[REG_EDX];
+ break;
+ case UNW_X86_ESI:
+ *value = context_->uc_mcontext.gregs[REG_ESI];
+ break;
+ case UNW_X86_EDI:
+ *value = context_->uc_mcontext.gregs[REG_EDI];
+ break;
+ case UNW_X86_EBP:
+ *value = context_->uc_mcontext.gregs[REG_EBP];
+ break;
+ case UNW_X86_EIP:
+ *value = context_->uc_mcontext.gregs[REG_EIP];
+ break;
+ case UNW_X86_ESP:
+ *value = context_->uc_mcontext.gregs[REG_ESP];
+ break;
+ case UNW_X86_TRAPNO:
+ *value = context_->uc_mcontext.gregs[REG_TRAPNO];
+ break;
+ case UNW_X86_CS:
+ *value = context_->uc_mcontext.gregs[REG_CS];
+ break;
+ case UNW_X86_EFLAGS:
+ *value = context_->uc_mcontext.gregs[REG_EFL];
+ break;
+ case UNW_X86_SS:
+ *value = context_->uc_mcontext.gregs[REG_SS];
+ break;
+ default:
+ result = false;
+ }
+#endif
+ return result;
+}
+
+std::string BacktraceOffline::GetFunctionNameRaw(uintptr_t, uintptr_t* offset) {
+ // We don't have enough information to support this. And it is expensive.
+ *offset = 0;
+ 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()) {
+ 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;
+ }
+ return debug_frame;
+}
+
+static bool OmitEncodedValue(uint8_t encode, const uint8_t*& p) {
+ if (encode == DW_EH_PE_omit) {
+ return 0;
+ }
+ uint8_t format = encode & 0x0f;
+ switch (format) {
+ case DW_EH_PE_ptr:
+ p += sizeof(unw_word_t);
+ break;
+ case DW_EH_PE_uleb128:
+ case DW_EH_PE_sleb128:
+ while ((*p & 0x80) != 0) {
+ ++p;
+ }
+ ++p;
+ break;
+ case DW_EH_PE_udata2:
+ case DW_EH_PE_sdata2:
+ p += 2;
+ break;
+ case DW_EH_PE_udata4:
+ case DW_EH_PE_sdata4:
+ p += 4;
+ break;
+ case DW_EH_PE_udata8:
+ case DW_EH_PE_sdata8:
+ p += 8;
+ break;
+ default:
+ return false;
+ }
+ return true;
+}
+
+static bool GetFdeTableOffsetInEhFrameHdr(const std::vector<uint8_t>& data,
+ uint64_t* table_offset_in_eh_frame_hdr) {
+ const uint8_t* p = data.data();
+ const uint8_t* end = p + data.size();
+ if (p + 4 > end) {
+ return false;
+ }
+ uint8_t version = *p++;
+ if (version != 1) {
+ return false;
+ }
+ uint8_t eh_frame_ptr_encode = *p++;
+ uint8_t fde_count_encode = *p++;
+ uint8_t fde_table_encode = *p++;
+
+ if (fde_table_encode != (DW_EH_PE_datarel | DW_EH_PE_sdata4)) {
+ return false;
+ }
+
+ if (!OmitEncodedValue(eh_frame_ptr_encode, p) || !OmitEncodedValue(fde_count_encode, p)) {
+ return false;
+ }
+ if (p >= end) {
+ return false;
+ }
+ *table_offset_in_eh_frame_hdr = p - data.data();
+ return true;
+}
+
+using ProgramHeader = DebugFrameInfo::EhFrame::ProgramHeader;
+
+template <class ELFT>
+DebugFrameInfo* ReadDebugFrameFromELFFile(const llvm::object::ELFFile<ELFT>* elf) {
+ 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->begin_sections(); it != elf->end_sections(); ++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;
+ 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;
+ }
+ } else if (name.get() == ".eh_frame") {
+ has_eh_frame = true;
+ 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;
+ }
+ }
+ }
+ }
+ 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;
+ }
+
+ std::vector<ProgramHeader> program_headers;
+ for (auto it = elf->begin_program_headers(); it != elf->end_program_headers(); ++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;
+}
+
+static DebugFrameInfo* ReadDebugFrameFromFile(const std::string& filename) {
+ auto owning_binary = llvm::object::createBinary(llvm::StringRef(filename));
+ if (owning_binary.getError()) {
+ return nullptr;
+ }
+ llvm::object::Binary* binary = owning_binary.get().getBinary();
+ auto obj = llvm::dyn_cast<llvm::object::ObjectFile>(binary);
+ if (obj == nullptr) {
+ return nullptr;
+ }
+ if (auto elf = llvm::dyn_cast<llvm::object::ELF32LEObjectFile>(obj)) {
+ return ReadDebugFrameFromELFFile(elf->getELFFile());
+ }
+ if (auto elf = llvm::dyn_cast<llvm::object::ELF64LEObjectFile>(obj)) {
+ return ReadDebugFrameFromELFFile(elf->getELFFile());
+ }
+ return nullptr;
+}
diff --git a/libbacktrace/BacktraceOffline.h b/libbacktrace/BacktraceOffline.h
new file mode 100644
index 0000000..42f826d
--- /dev/null
+++ b/libbacktrace/BacktraceOffline.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _LIBBACKTRACE_UNWIND_OFFLINE_H
+#define _LIBBACKTRACE_UNWIND_OFFLINE_H
+
+#include <libunwind.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <ucontext.h>
+
+#include <unordered_map>
+#include <unordered_set>
+
+#include <backtrace/Backtrace.h>
+
+struct Space {
+ uint64_t start;
+ uint64_t end;
+ const uint8_t* data;
+
+ Space() {
+ Clear();
+ }
+
+ void Clear();
+ 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;
+};
+
+class BacktraceOffline : public Backtrace {
+ public:
+ BacktraceOffline(pid_t pid, pid_t tid, BacktraceMap* map, const backtrace_stackinfo_t& stack,
+ bool cache_file)
+ : Backtrace(pid, tid, map),
+ cache_file_(cache_file),
+ context_(nullptr),
+ last_debug_frame_(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_;
+ }
+ }
+
+ bool Unwind(size_t num_ignore_frames, ucontext_t* context) override;
+
+ bool ReadWord(uintptr_t ptr, word_t* out_value) override;
+
+ size_t Read(uintptr_t addr, uint8_t* buffer, size_t bytes) override;
+
+ bool FindProcInfo(unw_addr_space_t addr_space, uint64_t ip, unw_proc_info_t* proc_info,
+ int need_unwind_info);
+
+ bool ReadReg(size_t reg_index, uint64_t* value);
+
+ protected:
+ 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 stack_space_;
+ DebugFrameInfo* last_debug_frame_;
+};
+
+#endif // _LIBBACKTRACE_BACKTRACE_OFFLINE_H
diff --git a/libbacktrace/backtrace_offline_test.cpp b/libbacktrace/backtrace_offline_test.cpp
new file mode 100644
index 0000000..88a3533
--- /dev/null
+++ b/libbacktrace/backtrace_offline_test.cpp
@@ -0,0 +1,189 @@
+#include <libunwind.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <functional>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <backtrace/Backtrace.h>
+#include <backtrace/BacktraceMap.h>
+#include <cutils/threads.h>
+
+#include <gtest/gtest.h>
+
+extern "C" {
+// Prototypes for functions in the test library.
+int test_level_one(int, int, int, int, void (*)(void*), void*);
+int test_level_two(int, int, int, int, void (*)(void*), void*);
+int test_level_three(int, int, int, int, void (*)(void*), void*);
+int test_level_four(int, int, int, int, void (*)(void*), void*);
+int test_recursive_call(int, void (*)(void*), void*);
+}
+
+static volatile bool g_exit_flag = false;
+
+static void GetContextAndExit(void* arg) {
+ unw_context_t* unw_context = reinterpret_cast<unw_context_t*>(arg);
+ unw_getcontext(unw_context);
+ // Don't touch the stack anymore.
+ while (!g_exit_flag) {
+ }
+}
+
+struct OfflineThreadArg {
+ unw_context_t unw_context;
+ pid_t tid;
+ std::function<int(void (*)(void*), void*)> function;
+};
+
+static void* OfflineThreadFunc(void* arg) {
+ OfflineThreadArg* fn_arg = reinterpret_cast<OfflineThreadArg*>(arg);
+ fn_arg->tid = gettid();
+ fn_arg->function(GetContextAndExit, &fn_arg->unw_context);
+ return nullptr;
+}
+
+static ucontext_t GetUContextFromUnwContext(const unw_context_t& unw_context) {
+ ucontext_t ucontext;
+ memset(&ucontext, 0, sizeof(ucontext));
+#if defined(__arm__)
+ ucontext.uc_mcontext.arm_r0 = unw_context.regs[0];
+ ucontext.uc_mcontext.arm_r1 = unw_context.regs[1];
+ ucontext.uc_mcontext.arm_r2 = unw_context.regs[2];
+ ucontext.uc_mcontext.arm_r3 = unw_context.regs[3];
+ ucontext.uc_mcontext.arm_r4 = unw_context.regs[4];
+ ucontext.uc_mcontext.arm_r5 = unw_context.regs[5];
+ ucontext.uc_mcontext.arm_r6 = unw_context.regs[6];
+ ucontext.uc_mcontext.arm_r7 = unw_context.regs[7];
+ ucontext.uc_mcontext.arm_r8 = unw_context.regs[8];
+ ucontext.uc_mcontext.arm_r9 = unw_context.regs[9];
+ ucontext.uc_mcontext.arm_r10 = unw_context.regs[10];
+ ucontext.uc_mcontext.arm_fp = unw_context.regs[11];
+ ucontext.uc_mcontext.arm_ip = unw_context.regs[12];
+ ucontext.uc_mcontext.arm_sp = unw_context.regs[13];
+ ucontext.uc_mcontext.arm_lr = unw_context.regs[14];
+ ucontext.uc_mcontext.arm_pc = unw_context.regs[15];
+#else
+ ucontext.uc_mcontext = unw_context.uc_mcontext;
+#endif
+ return ucontext;
+}
+
+static void OfflineBacktraceFunctionCall(std::function<int(void (*)(void*), void*)> function,
+ std::vector<uintptr_t>* pc_values) {
+ // Create a thread to generate the needed stack and registers information.
+ g_exit_flag = false;
+ const size_t stack_size = 1024 * 1024;
+ void* stack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ ASSERT_NE(MAP_FAILED, stack);
+ uintptr_t stack_addr = reinterpret_cast<uintptr_t>(stack);
+ pthread_attr_t attr;
+ ASSERT_EQ(0, pthread_attr_init(&attr));
+ ASSERT_EQ(0, pthread_attr_setstack(&attr, reinterpret_cast<void*>(stack), stack_size));
+ pthread_t thread;
+ OfflineThreadArg arg;
+ arg.function = function;
+ ASSERT_EQ(0, pthread_create(&thread, &attr, OfflineThreadFunc, &arg));
+ // Wait for the offline thread to generate the stack and unw_context information.
+ sleep(1);
+ // Copy the stack information.
+ std::vector<uint8_t> stack_data(reinterpret_cast<uint8_t*>(stack),
+ reinterpret_cast<uint8_t*>(stack) + stack_size);
+ g_exit_flag = true;
+ ASSERT_EQ(0, pthread_join(thread, nullptr));
+ ASSERT_EQ(0, munmap(stack, stack_size));
+
+ // Do offline backtrace.
+ std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(getpid()));
+ ASSERT_TRUE(map != nullptr);
+
+ backtrace_stackinfo_t stack_info;
+ stack_info.start = stack_addr;
+ stack_info.end = stack_addr + stack_size;
+ stack_info.data = stack_data.data();
+
+ std::unique_ptr<Backtrace> backtrace(
+ Backtrace::CreateOffline(getpid(), arg.tid, map.get(), stack_info));
+ ASSERT_TRUE(backtrace != nullptr);
+
+ ucontext_t ucontext = GetUContextFromUnwContext(arg.unw_context);
+ ASSERT_TRUE(backtrace->Unwind(0, &ucontext));
+
+ // Collect pc values of the call stack frames.
+ for (size_t i = 0; i < backtrace->NumFrames(); ++i) {
+ pc_values->push_back(backtrace->GetFrame(i)->pc);
+ }
+}
+
+// Return the name of the function which matches the address. Although we don't know the
+// exact end of each function, it is accurate enough for the tests.
+static std::string FunctionNameForAddress(uintptr_t addr) {
+ struct FunctionSymbol {
+ std::string name;
+ uintptr_t start;
+ uintptr_t end;
+ };
+
+ static std::vector<FunctionSymbol> symbols;
+ if (symbols.empty()) {
+ symbols = std::vector<FunctionSymbol>{
+ {"unknown_start", 0, 0},
+ {"test_level_one", reinterpret_cast<uintptr_t>(&test_level_one), 0},
+ {"test_level_two", reinterpret_cast<uintptr_t>(&test_level_two), 0},
+ {"test_level_three", reinterpret_cast<uintptr_t>(&test_level_three), 0},
+ {"test_level_four", reinterpret_cast<uintptr_t>(&test_level_four), 0},
+ {"test_recursive_call", reinterpret_cast<uintptr_t>(&test_recursive_call), 0},
+ {"GetContextAndExit", reinterpret_cast<uintptr_t>(&GetContextAndExit), 0},
+ {"unknown_end", static_cast<uintptr_t>(-1), static_cast<uintptr_t>(-1)},
+ };
+ std::sort(
+ symbols.begin(), symbols.end(),
+ [](const FunctionSymbol& s1, const FunctionSymbol& s2) { return s1.start < s2.start; });
+ for (size_t i = 0; i + 1 < symbols.size(); ++i) {
+ symbols[i].end = symbols[i + 1].start;
+ }
+ }
+ for (auto& symbol : symbols) {
+ if (addr >= symbol.start && addr < symbol.end) {
+ return symbol.name;
+ }
+ }
+ return "";
+}
+
+TEST(libbacktrace, offline) {
+ std::function<int(void (*)(void*), void*)> function =
+ std::bind(test_level_one, 1, 2, 3, 4, std::placeholders::_1, std::placeholders::_2);
+ std::vector<uintptr_t> pc_values;
+ OfflineBacktraceFunctionCall(function, &pc_values);
+ ASSERT_FALSE(pc_values.empty());
+ ASSERT_LE(pc_values.size(), static_cast<size_t>(MAX_BACKTRACE_FRAMES));
+
+ size_t test_one_index = 0;
+ for (size_t i = 0; i < pc_values.size(); ++i) {
+ if (FunctionNameForAddress(pc_values[i]) == "test_level_one") {
+ test_one_index = i;
+ break;
+ }
+ }
+
+ ASSERT_GE(test_one_index, 3u);
+ ASSERT_EQ("test_level_one", FunctionNameForAddress(pc_values[test_one_index]));
+ ASSERT_EQ("test_level_two", FunctionNameForAddress(pc_values[test_one_index - 1]));
+ ASSERT_EQ("test_level_three", FunctionNameForAddress(pc_values[test_one_index - 2]));
+ ASSERT_EQ("test_level_four", FunctionNameForAddress(pc_values[test_one_index - 3]));
+}
+
+TEST(libbacktrace, offline_max_trace) {
+ std::function<int(void (*)(void*), void*)> function = std::bind(
+ test_recursive_call, MAX_BACKTRACE_FRAMES + 10, std::placeholders::_1, std::placeholders::_2);
+ std::vector<uintptr_t> pc_values;
+ OfflineBacktraceFunctionCall(function, &pc_values);
+ ASSERT_FALSE(pc_values.empty());
+ ASSERT_EQ(static_cast<size_t>(MAX_BACKTRACE_FRAMES), pc_values.size());
+ ASSERT_EQ("test_recursive_call", FunctionNameForAddress(pc_values.back()));
+}