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![Nick Desaulniers](/assets/img/avatar_default.png)
LLVM changed the expected function signatures for llvm_gcda_start_file() and llvm_gcda_emit_function() in the clang-11 release. Drop the older implementations and require folks to upgrade their compiler if they're interested in GCOV support. Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041 Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44 Link: https://lkml.kernel.org/r/20210312224132.3413602-3-ndesaulniers@google.com Link: https://lkml.kernel.org/r/20210413183113.2977432-1-ndesaulniers@google.com Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Suggested-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Cc: Prasad Sodagudi <psodagud@quicinc.com> Cc: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
391 lines
10 KiB
C
391 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2019 Google, Inc.
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* modified from kernel/gcov/gcc_4_7.c
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*
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* LLVM uses profiling data that's deliberately similar to GCC, but has a
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* very different way of exporting that data. LLVM calls llvm_gcov_init() once
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* per module, and provides a couple of callbacks that we can use to ask for
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* more data.
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*
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* We care about the "writeout" callback, which in turn calls back into
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* compiler-rt/this module to dump all the gathered coverage data to disk:
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*
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* llvm_gcda_start_file()
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* llvm_gcda_emit_function()
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* llvm_gcda_emit_arcs()
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* llvm_gcda_emit_function()
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* llvm_gcda_emit_arcs()
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* [... repeats for each function ...]
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* llvm_gcda_summary_info()
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* llvm_gcda_end_file()
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*
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* This design is much more stateless and unstructured than gcc's, and is
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* intended to run at process exit. This forces us to keep some local state
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* about which module we're dealing with at the moment. On the other hand, it
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* also means we don't depend as much on how LLVM represents profiling data
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* internally.
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*
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* See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
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* details on how this works, particularly GCOVProfiler::emitProfileArcs(),
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* GCOVProfiler::insertCounterWriteout(), and
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* GCOVProfiler::insertFlush().
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*/
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#define pr_fmt(fmt) "gcov: " fmt
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/printk.h>
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#include <linux/ratelimit.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include "gcov.h"
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typedef void (*llvm_gcov_callback)(void);
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struct gcov_info {
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struct list_head head;
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const char *filename;
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unsigned int version;
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u32 checksum;
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struct list_head functions;
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};
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struct gcov_fn_info {
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struct list_head head;
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u32 ident;
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u32 checksum;
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u32 cfg_checksum;
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u32 num_counters;
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u64 *counters;
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};
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static struct gcov_info *current_info;
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static LIST_HEAD(clang_gcov_list);
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void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush)
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{
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struct gcov_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return;
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INIT_LIST_HEAD(&info->head);
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INIT_LIST_HEAD(&info->functions);
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mutex_lock(&gcov_lock);
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list_add_tail(&info->head, &clang_gcov_list);
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current_info = info;
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writeout();
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current_info = NULL;
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if (gcov_events_enabled)
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gcov_event(GCOV_ADD, info);
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mutex_unlock(&gcov_lock);
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}
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EXPORT_SYMBOL(llvm_gcov_init);
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void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
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{
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current_info->filename = orig_filename;
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current_info->version = version;
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current_info->checksum = checksum;
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}
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EXPORT_SYMBOL(llvm_gcda_start_file);
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void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum)
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{
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struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return;
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INIT_LIST_HEAD(&info->head);
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info->ident = ident;
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info->checksum = func_checksum;
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info->cfg_checksum = cfg_checksum;
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list_add_tail(&info->head, ¤t_info->functions);
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}
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EXPORT_SYMBOL(llvm_gcda_emit_function);
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void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
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{
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struct gcov_fn_info *info = list_last_entry(¤t_info->functions,
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struct gcov_fn_info, head);
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info->num_counters = num_counters;
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info->counters = counters;
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}
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EXPORT_SYMBOL(llvm_gcda_emit_arcs);
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void llvm_gcda_summary_info(void)
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{
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}
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EXPORT_SYMBOL(llvm_gcda_summary_info);
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void llvm_gcda_end_file(void)
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{
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}
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EXPORT_SYMBOL(llvm_gcda_end_file);
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/**
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* gcov_info_filename - return info filename
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* @info: profiling data set
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*/
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const char *gcov_info_filename(struct gcov_info *info)
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{
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return info->filename;
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}
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/**
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* gcov_info_version - return info version
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* @info: profiling data set
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*/
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unsigned int gcov_info_version(struct gcov_info *info)
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{
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return info->version;
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}
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/**
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* gcov_info_next - return next profiling data set
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* @info: profiling data set
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*
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* Returns next gcov_info following @info or first gcov_info in the chain if
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* @info is %NULL.
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*/
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struct gcov_info *gcov_info_next(struct gcov_info *info)
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{
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if (!info)
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return list_first_entry_or_null(&clang_gcov_list,
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struct gcov_info, head);
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if (list_is_last(&info->head, &clang_gcov_list))
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return NULL;
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return list_next_entry(info, head);
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}
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/**
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* gcov_info_link - link/add profiling data set to the list
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* @info: profiling data set
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*/
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void gcov_info_link(struct gcov_info *info)
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{
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list_add_tail(&info->head, &clang_gcov_list);
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}
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/**
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* gcov_info_unlink - unlink/remove profiling data set from the list
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* @prev: previous profiling data set
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* @info: profiling data set
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*/
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void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
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{
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/* Generic code unlinks while iterating. */
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__list_del_entry(&info->head);
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}
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/**
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* gcov_info_within_module - check if a profiling data set belongs to a module
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* @info: profiling data set
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* @mod: module
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*
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* Returns true if profiling data belongs module, false otherwise.
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*/
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bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
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{
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return within_module((unsigned long)info->filename, mod);
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}
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/* Symbolic links to be created for each profiling data file. */
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const struct gcov_link gcov_link[] = {
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{ OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
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{ 0, NULL},
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};
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/**
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* gcov_info_reset - reset profiling data to zero
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* @info: profiling data set
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*/
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void gcov_info_reset(struct gcov_info *info)
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{
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struct gcov_fn_info *fn;
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list_for_each_entry(fn, &info->functions, head)
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memset(fn->counters, 0,
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sizeof(fn->counters[0]) * fn->num_counters);
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}
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/**
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* gcov_info_is_compatible - check if profiling data can be added
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* @info1: first profiling data set
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* @info2: second profiling data set
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*
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* Returns non-zero if profiling data can be added, zero otherwise.
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*/
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int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
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{
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struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null(
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&info1->functions, struct gcov_fn_info, head);
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struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null(
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&info2->functions, struct gcov_fn_info, head);
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if (info1->checksum != info2->checksum)
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return false;
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if (!fn_ptr1)
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return fn_ptr1 == fn_ptr2;
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while (!list_is_last(&fn_ptr1->head, &info1->functions) &&
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!list_is_last(&fn_ptr2->head, &info2->functions)) {
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if (fn_ptr1->checksum != fn_ptr2->checksum)
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return false;
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if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
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return false;
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fn_ptr1 = list_next_entry(fn_ptr1, head);
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fn_ptr2 = list_next_entry(fn_ptr2, head);
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}
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return list_is_last(&fn_ptr1->head, &info1->functions) &&
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list_is_last(&fn_ptr2->head, &info2->functions);
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}
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/**
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* gcov_info_add - add up profiling data
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* @dest: profiling data set to which data is added
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* @source: profiling data set which is added
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*
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* Adds profiling counts of @source to @dest.
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*/
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void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
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{
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struct gcov_fn_info *dfn_ptr;
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struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions,
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struct gcov_fn_info, head);
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list_for_each_entry(dfn_ptr, &dst->functions, head) {
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u32 i;
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for (i = 0; i < sfn_ptr->num_counters; i++)
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dfn_ptr->counters[i] += sfn_ptr->counters[i];
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}
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}
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static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
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{
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size_t cv_size; /* counter values size */
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struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn),
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GFP_KERNEL);
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if (!fn_dup)
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return NULL;
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INIT_LIST_HEAD(&fn_dup->head);
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cv_size = fn->num_counters * sizeof(fn->counters[0]);
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fn_dup->counters = kvmalloc(cv_size, GFP_KERNEL);
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if (!fn_dup->counters) {
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kfree(fn_dup);
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return NULL;
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}
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memcpy(fn_dup->counters, fn->counters, cv_size);
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return fn_dup;
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}
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/**
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* gcov_info_dup - duplicate profiling data set
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* @info: profiling data set to duplicate
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*
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* Return newly allocated duplicate on success, %NULL on error.
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*/
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struct gcov_info *gcov_info_dup(struct gcov_info *info)
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{
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struct gcov_info *dup;
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struct gcov_fn_info *fn;
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dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
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if (!dup)
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return NULL;
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INIT_LIST_HEAD(&dup->head);
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INIT_LIST_HEAD(&dup->functions);
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dup->filename = kstrdup(info->filename, GFP_KERNEL);
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if (!dup->filename)
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goto err;
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list_for_each_entry(fn, &info->functions, head) {
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struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn);
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if (!fn_dup)
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goto err;
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list_add_tail(&fn_dup->head, &dup->functions);
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}
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return dup;
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err:
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gcov_info_free(dup);
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return NULL;
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}
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/**
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* gcov_info_free - release memory for profiling data set duplicate
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* @info: profiling data set duplicate to free
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*/
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void gcov_info_free(struct gcov_info *info)
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{
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struct gcov_fn_info *fn, *tmp;
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list_for_each_entry_safe(fn, tmp, &info->functions, head) {
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kvfree(fn->counters);
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list_del(&fn->head);
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kfree(fn);
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}
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kfree(info->filename);
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kfree(info);
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}
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/**
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* convert_to_gcda - convert profiling data set to gcda file format
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* @buffer: the buffer to store file data or %NULL if no data should be stored
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* @info: profiling data set to be converted
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*
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* Returns the number of bytes that were/would have been stored into the buffer.
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*/
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size_t convert_to_gcda(char *buffer, struct gcov_info *info)
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{
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struct gcov_fn_info *fi_ptr;
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size_t pos = 0;
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/* File header. */
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pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
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pos += store_gcov_u32(buffer, pos, info->version);
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pos += store_gcov_u32(buffer, pos, info->checksum);
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list_for_each_entry(fi_ptr, &info->functions, head) {
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u32 i;
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pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
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pos += store_gcov_u32(buffer, pos, 3);
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pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
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pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
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pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
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pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE);
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pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2);
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for (i = 0; i < fi_ptr->num_counters; i++)
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pos += store_gcov_u64(buffer, pos, fi_ptr->counters[i]);
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}
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return pos;
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}
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