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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/usr/gcov.h $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* COPYRIGHT International Business Machines Corp. 2012,2014 */
/* */
/* 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. */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __USR_GCOV_H
#define __USR_GCOV_H
/** @file gcov.h
* @brief Header file to generate gcov_info chain for each module.
*
* Each gcov-instrumented module needs to have its own gcov_info chain
* and associated linking function. Each .o file will have its own
* gcov_info object which is added to the chain when the module is loaded
* (static initializers) by calling the __gcov_init function.
*
* We make the gcov_info chain unique per-module, instead of a single
* global chain, so that we don't have bad pointers if a module was
* loaded and then unloaded.
*/
#include <stddef.h>
#include <stdint.h>
#include <string.h>
/** @struct gcov_info
* @brief Structure generated by gcc. Do not use.
*
* This structure is automatically generated and instances of it created by
* gcc when the --coverage compile option is used. We don't need to
* manipulate this structure from code except:
* 1) To fix up the chains as objects are added to the chain.
* 2) To copy the gcov_info and counters into the base-chain when we
* unload a module.
*
* The rest of this structure is parsed by the Gcov.pm debug tool.
*
* Most of the items in here are used as uint32_t's by gcov but are still
* aligned on a 64-bit boundary. The unusedN fields are to ensure proper
* alignment.
*/
struct gcov_info
{
uint32_t version;
uint32_t unused0;
gcov_info* next;
uint32_t timestamp;
uint32_t unused1;
char* filename;
uint32_t n_functions;
uint32_t unused2;
void* functions;
uint32_t counter_mask;
uint32_t unused3;
uint32_t n_counters;
uint32_t unused4;
uint64_t* counters;
} PACKED;
// Preprocessor magic to create a variable name based off the module name.
// GCOV_INFO_OBJ() will create a post-processed name like
// 'foobar_gcov_info_head' or 'core_gcov_info_head'.
#ifdef __HOSTBOOT_MODULE
#define __GCOV_PREFIX __HOSTBOOT_MODULE
#define ___GCOV_STRINGIFY(X) #X
#define __GCOV_STRINGIFY(X) ___GCOV_STRINGIFY(X)
#define __GCOV_PREFIX_NAME __GCOV_STRINGIFY(__HOSTBOOT_MODULE)
#else
#define __GCOV_PREFIX core
#define __GCOV_PREFIX_NAME "core"
#endif
#define __GCOV_INFO_OBJ(X,Y) X ## Y
#define _GCOV_INFO_OBJ(X,Y) __GCOV_INFO_OBJ(X,Y)
#define GCOV_INFO_OBJ() _GCOV_INFO_OBJ(__GCOV_PREFIX, _gcov_info_head)
/** Pointer to the beginning of the gcov_info chain for this module. */
gcov_info* GCOV_INFO_OBJ() = NULL;
/** Function called by module loading to add the object gcov_info instance
* to the chain.
*/
extern "C"
void __gcov_init(gcov_info* i_info)
{
// Atomically push i_info onto the gcov_info_head stack.
do
{
i_info->next = GCOV_INFO_OBJ();
} while (!__sync_bool_compare_and_swap(&GCOV_INFO_OBJ(),
i_info->next, i_info));
}
// This ifdef has two pieces of code which are used in module unloading.
//
// In the modules themselves we have a function that is registered via atexit
// to call to copy the contents of their own gcov_info chain into the base
// gcov_info chain. This is required because the module's memory is going
// away as it is unloaded.
//
// In the base code (non-modules) we have a single implementation of the
// code for actually doing a copy of the gcov_info chain into the base code's
// own chain. This is kept in just the base code for space savings.
//
#ifdef __HOSTBOOT_MODULE
// Forward declaration of __gcov_module_copychain for modules.
extern "C" void __gcov_module_copychain(gcov_info* chain);
/** Function called by module unloading to move the module's gcov_info
* instances to the global chain.
*/
extern "C"
void __gcov_module_unload(void* unused)
{
__gcov_module_copychain(GCOV_INFO_OBJ());
}
// Register __gcov_module_unload with __cxa_atexit.
extern void* __dso_handle;
extern "C" int __cxa_atexit(void(*)(void*),void*,void*);
int __unused_gcov_cxa_register =
__cxa_atexit(&__gcov_module_unload, NULL, __dso_handle);
#else
/** Function called by a module being unloaded (via __gcov_module_unload) to
* copy the module's gcov_info chain into the base gcov_info chain.
*/
extern "C"
void __gcov_module_copychain(gcov_info* chain)
{
while(chain != NULL)
{
// Copy old info.
gcov_info* new_info = new gcov_info();
memcpy(new_info, chain, sizeof(gcov_info));
// Copy old counters.
uint64_t* new_counters = new uint64_t[chain->n_counters]();
memcpy(new_counters, chain->counters,
chain->n_counters*sizeof(uint64_t));
new_info->counters = new_counters;
// Atomically push new_info onto the core_gcov_info_head stack.
do
{
new_info->next = GCOV_INFO_OBJ();
} while (!__sync_bool_compare_and_swap(&GCOV_INFO_OBJ(),
new_info->next, new_info));
// Advance to next info in this modules chain.
chain = chain->next;
}
}
#endif
/** Unneeded function but must be defined to compile.
*
* This function appears to be typically used by libgcov.so when instrumented
* on a real linux-based system. It can be used to merge counters across
* multiple runs or when a 'fork' occurs. It doesn't appear that this
* function ever gets called for us but the unresolved symbol is added to
* the module (by gcc) so we've created a stub here to pass compile.
*/
extern "C"
void __gcov_merge_add()
{
while(1);
}
#endif
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