forked from OSchip/llvm-project
116 lines
4.2 KiB
C++
116 lines
4.2 KiB
C++
//===-- xray_init.cpp -------------------------------------------*- C++ -*-===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file is a part of XRay, a dynamic runtime instrumentation system.
|
|
//
|
|
// XRay initialisation logic.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include <fcntl.h>
|
|
#include <strings.h>
|
|
#include <unistd.h>
|
|
|
|
#include "sanitizer_common/sanitizer_common.h"
|
|
#include "xray_defs.h"
|
|
#include "xray_flags.h"
|
|
#include "xray_interface_internal.h"
|
|
|
|
extern "C" {
|
|
void __xray_init();
|
|
extern const XRaySledEntry __start_xray_instr_map[] __attribute__((weak));
|
|
extern const XRaySledEntry __stop_xray_instr_map[] __attribute__((weak));
|
|
extern const XRayFunctionSledIndex __start_xray_fn_idx[] __attribute__((weak));
|
|
extern const XRayFunctionSledIndex __stop_xray_fn_idx[] __attribute__((weak));
|
|
|
|
#if SANITIZER_MAC
|
|
// HACK: This is a temporary workaround to make XRay build on
|
|
// Darwin, but it will probably not work at runtime.
|
|
const XRaySledEntry __start_xray_instr_map[] = {};
|
|
extern const XRaySledEntry __stop_xray_instr_map[] = {};
|
|
extern const XRayFunctionSledIndex __start_xray_fn_idx[] = {};
|
|
extern const XRayFunctionSledIndex __stop_xray_fn_idx[] = {};
|
|
#endif
|
|
}
|
|
|
|
using namespace __xray;
|
|
|
|
// When set to 'true' this means the XRay runtime has been initialised. We use
|
|
// the weak symbols defined above (__start_xray_inst_map and
|
|
// __stop_xray_instr_map) to initialise the instrumentation map that XRay uses
|
|
// for runtime patching/unpatching of instrumentation points.
|
|
//
|
|
// FIXME: Support DSO instrumentation maps too. The current solution only works
|
|
// for statically linked executables.
|
|
atomic_uint8_t XRayInitialized{0};
|
|
|
|
// This should always be updated before XRayInitialized is updated.
|
|
SpinMutex XRayInstrMapMutex;
|
|
XRaySledMap XRayInstrMap;
|
|
|
|
// Global flag to determine whether the flags have been initialized.
|
|
atomic_uint8_t XRayFlagsInitialized{0};
|
|
|
|
// A mutex to allow only one thread to initialize the XRay data structures.
|
|
SpinMutex XRayInitMutex;
|
|
|
|
// __xray_init() will do the actual loading of the current process' memory map
|
|
// and then proceed to look for the .xray_instr_map section/segment.
|
|
void __xray_init() XRAY_NEVER_INSTRUMENT {
|
|
SpinMutexLock Guard(&XRayInitMutex);
|
|
// Short-circuit if we've already initialized XRay before.
|
|
if (atomic_load(&XRayInitialized, memory_order_acquire))
|
|
return;
|
|
|
|
// XRAY is not compatible with PaX MPROTECT
|
|
CheckMPROTECT();
|
|
|
|
if (!atomic_load(&XRayFlagsInitialized, memory_order_acquire)) {
|
|
initializeFlags();
|
|
atomic_store(&XRayFlagsInitialized, true, memory_order_release);
|
|
}
|
|
|
|
if (__start_xray_instr_map == nullptr) {
|
|
if (Verbosity())
|
|
Report("XRay instrumentation map missing. Not initializing XRay.\n");
|
|
return;
|
|
}
|
|
|
|
{
|
|
SpinMutexLock Guard(&XRayInstrMapMutex);
|
|
XRayInstrMap.Sleds = __start_xray_instr_map;
|
|
XRayInstrMap.Entries = __stop_xray_instr_map - __start_xray_instr_map;
|
|
XRayInstrMap.SledsIndex = __start_xray_fn_idx;
|
|
XRayInstrMap.Functions = __stop_xray_fn_idx - __start_xray_fn_idx;
|
|
}
|
|
atomic_store(&XRayInitialized, true, memory_order_release);
|
|
|
|
#ifndef XRAY_NO_PREINIT
|
|
if (flags()->patch_premain)
|
|
__xray_patch();
|
|
#endif
|
|
}
|
|
|
|
// FIXME: Make check-xray tests work on FreeBSD without
|
|
// SANITIZER_CAN_USE_PREINIT_ARRAY.
|
|
// See sanitizer_internal_defs.h where the macro is defined.
|
|
// Calling unresolved PLT functions in .preinit_array can lead to deadlock on
|
|
// FreeBSD but here it seems benign.
|
|
#if !defined(XRAY_NO_PREINIT) && \
|
|
(SANITIZER_CAN_USE_PREINIT_ARRAY || SANITIZER_FREEBSD)
|
|
// Only add the preinit array initialization if the sanitizers can.
|
|
__attribute__((section(".preinit_array"),
|
|
used)) void (*__local_xray_preinit)(void) = __xray_init;
|
|
#else
|
|
// If we cannot use the .preinit_array section, we should instead use dynamic
|
|
// initialisation.
|
|
__attribute__ ((constructor (0)))
|
|
static void __local_xray_dyninit() {
|
|
__xray_init();
|
|
}
|
|
#endif
|