Hash :
f62405c5
Author :
Date :
2022-10-31T18:47:52
Add utilities to get the Android backtrace
* Added getBacktraceInfo(), which returns the backtrace information
from the ANGLE code, including the addresses and the symbols if
possible
* Returns the data in an instance of the new class BacktraceInfo.
* In order to access this function, backtrace_utils.h has been
included in vk_utils.h
* New GN flag to make use of this feature:
* angle_enable_unwind_backtrace_support
* Current only available on Android (debug mode)
* If the flag is disabled, getBacktraceInfo() returns an empty
object.
* Added functions in util/ (per platform) to print the BacktraceInfo
data.
* Example of usage:
angle::printBacktraceInfo(angle::getBacktraceInfo());
* Minor edit: Moved cstdint from android_util.cpp to its header.
Bug: b/258475923
Change-Id: I6115462a1a2845d40c7cafc14ce52df09ecdcf34
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3995843
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Charlie Lao <cclao@google.com>
Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com>
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//
// Copyright 2022 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// backtrace_utils_android.cpp:
// Implements the functions related to the backtrace info class for Android platforms.
//
#include "backtrace_utils.h"
#include <dlfcn.h>
#include <unwind.h>
namespace
{
// Size limit for the backtrace obtained from the device.
constexpr uint32_t kMaxBacktraceSize = 16;
struct UnwindCallbackFnState
{
UnwindCallbackFnState() : current(nullptr), end(nullptr) {}
UnwindCallbackFnState(void **current, void **end) : current(current), end(end) {}
void **current;
void **end;
};
// Unwind callback function, which is called until the end of stack is reached.
_Unwind_Reason_Code unwindCallbackFn(struct _Unwind_Context *context, void *args)
{
auto *state = reinterpret_cast<UnwindCallbackFnState *>(args);
// Get the instruction pointer.
uintptr_t ip = _Unwind_GetIP(context);
if (ip == 0)
{
return _URC_NO_REASON;
}
// The buffer is populated at the current location with the instruction pointer address. The
// current value is incremented to prepare for the next entry in the stack trace. Once "current"
// gets to "end", the callback should stop.
if (state->current == state->end)
{
return _URC_END_OF_STACK;
}
*state->current++ = reinterpret_cast<void *>(ip);
return _URC_NO_REASON;
}
} // namespace
namespace angle
{
void BacktraceInfo::populateBacktraceInfo(void **stackAddressBuffer, size_t stackAddressCount)
{
ASSERT(mStackAddresses.empty() && mStackSymbols.empty());
for (size_t i = 0; i < stackAddressCount; i++)
{
void *stackAddr = stackAddressBuffer[i];
mStackAddresses.push_back(stackAddr);
// Get the symbol if possible. dladdr() returns 0 on failure.
Dl_info dlInfo;
if (dladdr(stackAddr, &dlInfo) != 0 && dlInfo.dli_sname)
{
mStackSymbols.emplace_back(dlInfo.dli_sname);
}
else
{
mStackSymbols.emplace_back("unknown_symbol");
}
}
ASSERT(mStackAddresses.size() == mStackSymbols.size());
}
BacktraceInfo getBacktraceInfo()
{
void *stackAddrBuffer[kMaxBacktraceSize];
UnwindCallbackFnState unwindFnState(stackAddrBuffer, stackAddrBuffer + kMaxBacktraceSize);
_Unwind_Backtrace(unwindCallbackFn, &unwindFnState);
// The number of the collected IPs is shown by how far "current" has moved.
auto stackAddressCount = static_cast<size_t>(unwindFnState.current - stackAddrBuffer);
BacktraceInfo backtraceInfo;
backtraceInfo.populateBacktraceInfo(stackAddrBuffer, stackAddressCount);
return backtraceInfo;
}
// The following function has been defined in each platform separately.
// - void printBacktraceInfo(BacktraceInfo backtraceInfo);
} // namespace angle