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// Copyright 2014 The Crashpad Authors. All rights reserved.
// 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#include "build/build_config.h"
#if defined(OS_IOS)
#include <sys/ucontext.h>
#elif defined(OS_MACOSX)
#include <mach/mach.h>
#elif defined(OS_WIN)
#include <windows.h>
#elif defined(OS_LINUX) || defined(OS_ANDROID)
#include <ucontext.h>
#elif defined(OS_FUCHSIA)
#include <signal.h>
#endif // OS_MACOSX
namespace crashpad {
#if defined(OS_IOS)
using NativeCPUContext = ucontext_t;
#elif defined(OS_MACOSX)
#if defined(ARCH_CPU_X86_FAMILY)
using NativeCPUContext = x86_thread_state;
#elif defined(OS_WIN)
using NativeCPUContext = CONTEXT;
#elif defined(OS_LINUX) || defined(OS_ANDROID) || defined(OS_FUCHSIA)
using NativeCPUContext = ucontext_t;
#endif // OS_MACOSX
//! \brief Saves the CPU context.
//! The CPU context will be captured as accurately and completely as possible,
//! containing an atomic snapshot at the point of this function’s return. This
//! function does not modify any registers.
//! This function is a replacement for `RtlCaptureContext()` and `getcontext()`
//! which contain bugs and/or limitations.
//! On 32-bit x86, `RtlCaptureContext()` requires that `ebp` be used as a frame
//! pointer, and returns `ebp`, `esp`, and `eip` out of sync with the other
//! registers. Both the 32-bit x86 and 64-bit x86_64 versions of
//! `RtlCaptureContext()` capture only the state of the integer registers,
//! ignoring floating-point and vector state.
//! \param[out] cpu_context The structure to store the context in.
//! \note The ABI may require that this function's argument is passed by
//! register, preventing this fuction from saving the original value of that
//! register. This occurs in the following circumstances:
//! OS | Architecture | Register
//! --------------------|--------------|---------
//! Win | x86_64 | `%%rcx`
//! macOS/Linux/Fuchsia | x86_64 | `%%rdi`
//! Linux | ARM/ARM64 | `r0`/`x0`
//! Linux | MIPS/MIPS64 | `$a0`
//! Additionally, the value `LR` on ARM/ARM64 will be the return address of
//! this function.
//! If the value of these register prior to calling this function are needed
//! they must be obtained separately prior to calling this function. For
//! example:
//! \code
//! uint64_t rdi;
//! asm("movq %%rdi, %0" : "=m"(rdi));
//! \endcode
void CaptureContext(NativeCPUContext* cpu_context);
} // namespace crashpad