gcov: clang support (e178a5be) · Commits · 戴 / test

kernel/gcov/Kconfig

+2 −1

Original line number	Diff line number	Diff line
		@@ -53,6 +53,7 @@ config GCOV_PROFILE_ALL
		choice
		prompt "Specify GCOV format"
		depends on GCOV_KERNEL
		depends on CC_IS_GCC
		---help---
		The gcov format is usually determined by the GCC version, and the
		default is chosen according to your GCC version. However, there are
		@@ -62,7 +63,7 @@ choice

		config GCOV_FORMAT_3_4
		bool "GCC 3.4 format"
		depends on CC_IS_GCC && GCC_VERSION < 40700
		depends on GCC_VERSION < 40700
		---help---
		Select this option to use the format defined by GCC 3.4.

kernel/gcov/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -4,3 +4,4 @@ ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
		obj-y := base.o fs.o
		obj-$(CONFIG_GCOV_FORMAT_3_4) += gcc_base.o gcc_3_4.o
		obj-$(CONFIG_GCOV_FORMAT_4_7) += gcc_base.o gcc_4_7.o
		obj-$(CONFIG_CC_IS_CLANG) += clang.o

kernel/gcov/base.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -64,7 +64,7 @@ static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,

		/* Remove entries located in module from linked list. */
		while ((info = gcov_info_next(info))) {
		if (within_module((unsigned long)info, mod)) {
		if (gcov_info_within_module(info, mod)) {
		gcov_info_unlink(prev, info);
		if (gcov_events_enabled)
		gcov_event(GCOV_REMOVE, info);

kernel/gcov/clang.c

0 → 100644

+581 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		/*
		* Copyright (C) 2019 Google, Inc.
		* modified from kernel/gcov/gcc_4_7.c
		*
		* This software is licensed under the terms of the GNU General Public
		* License version 2, as published by the Free Software Foundation, and
		* may be copied, distributed, and modified under those terms.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		*
		* LLVM uses profiling data that's deliberately similar to GCC, but has a
		* very different way of exporting that data. LLVM calls llvm_gcov_init() once
		* per module, and provides a couple of callbacks that we can use to ask for
		* more data.
		*
		* We care about the "writeout" callback, which in turn calls back into
		* compiler-rt/this module to dump all the gathered coverage data to disk:
		*
		* llvm_gcda_start_file()
		* llvm_gcda_emit_function()
		* llvm_gcda_emit_arcs()
		* llvm_gcda_emit_function()
		* llvm_gcda_emit_arcs()
		* [... repeats for each function ...]
		* llvm_gcda_summary_info()
		* llvm_gcda_end_file()
		*
		* This design is much more stateless and unstructured than gcc's, and is
		* intended to run at process exit. This forces us to keep some local state
		* about which module we're dealing with at the moment. On the other hand, it
		* also means we don't depend as much on how LLVM represents profiling data
		* internally.
		*
		* See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
		* details on how this works, particularly GCOVProfiler::emitProfileArcs(),
		* GCOVProfiler::insertCounterWriteout(), and
		* GCOVProfiler::insertFlush().
		*/

		#define pr_fmt(fmt) "gcov: " fmt

		#include <linux/kernel.h>
		#include <linux/list.h>
		#include <linux/printk.h>
		#include <linux/ratelimit.h>
		#include <linux/seq_file.h>
		#include <linux/slab.h>
		#include <linux/vmalloc.h>
		#include "gcov.h"

		typedef void (*llvm_gcov_callback)(void);

		struct gcov_info {
		struct list_head head;

		const char *filename;
		unsigned int version;
		u32 checksum;

		struct list_head functions;
		};

		struct gcov_fn_info {
		struct list_head head;

		u32 ident;
		u32 checksum;
		u8 use_extra_checksum;
		u32 cfg_checksum;

		u32 num_counters;
		u64 *counters;
		const char *function_name;
		};

		static struct gcov_info *current_info;

		static LIST_HEAD(clang_gcov_list);

		void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush)
		{
		struct gcov_info info = kzalloc(sizeof(info), GFP_KERNEL);

		if (!info)
		return;

		INIT_LIST_HEAD(&info->head);
		INIT_LIST_HEAD(&info->functions);

		mutex_lock(&gcov_lock);

		list_add_tail(&info->head, &clang_gcov_list);
		current_info = info;
		writeout();
		current_info = NULL;
		if (gcov_events_enabled)
		gcov_event(GCOV_ADD, info);

		mutex_unlock(&gcov_lock);
		}
		EXPORT_SYMBOL(llvm_gcov_init);

		void llvm_gcda_start_file(const char *orig_filename, const char version[4],
		u32 checksum)
		{
		current_info->filename = orig_filename;
		memcpy(&current_info->version, version, sizeof(current_info->version));
		current_info->checksum = checksum;
		}
		EXPORT_SYMBOL(llvm_gcda_start_file);

		void llvm_gcda_emit_function(u32 ident, const char *function_name,
		u32 func_checksum, u8 use_extra_checksum, u32 cfg_checksum)
		{
		struct gcov_fn_info info = kzalloc(sizeof(info), GFP_KERNEL);

		if (!info)
		return;

		INIT_LIST_HEAD(&info->head);
		info->ident = ident;
		info->checksum = func_checksum;
		info->use_extra_checksum = use_extra_checksum;
		info->cfg_checksum = cfg_checksum;
		if (function_name)
		info->function_name = kstrdup(function_name, GFP_KERNEL);

		list_add_tail(&info->head, &current_info->functions);
		}
		EXPORT_SYMBOL(llvm_gcda_emit_function);

		void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
		{
		struct gcov_fn_info *info = list_last_entry(&current_info->functions,
		struct gcov_fn_info, head);

		info->num_counters = num_counters;
		info->counters = counters;
		}
		EXPORT_SYMBOL(llvm_gcda_emit_arcs);

		void llvm_gcda_summary_info(void)
		{
		}
		EXPORT_SYMBOL(llvm_gcda_summary_info);

		void llvm_gcda_end_file(void)
		{
		}
		EXPORT_SYMBOL(llvm_gcda_end_file);

		/**
		* gcov_info_filename - return info filename
		* @info: profiling data set
		*/
		const char gcov_info_filename(struct gcov_info info)
		{
		return info->filename;
		}

		/**
		* gcov_info_version - return info version
		* @info: profiling data set
		*/
		unsigned int gcov_info_version(struct gcov_info *info)
		{
		return info->version;
		}

		/**
		* gcov_info_next - return next profiling data set
		* @info: profiling data set
		*
		* Returns next gcov_info following @info or first gcov_info in the chain if
		* @info is %NULL.
		*/
		struct gcov_info gcov_info_next(struct gcov_info info)
		{
		if (!info)
		return list_first_entry_or_null(&clang_gcov_list,
		struct gcov_info, head);
		if (list_is_last(&info->head, &clang_gcov_list))
		return NULL;
		return list_next_entry(info, head);
		}

		/**
		* gcov_info_link - link/add profiling data set to the list
		* @info: profiling data set
		*/
		void gcov_info_link(struct gcov_info *info)
		{
		list_add_tail(&info->head, &clang_gcov_list);
		}

		/**
		* gcov_info_unlink - unlink/remove profiling data set from the list
		* @prev: previous profiling data set
		* @info: profiling data set
		*/
		void gcov_info_unlink(struct gcov_info prev, struct gcov_info info)
		{
		/* Generic code unlinks while iterating. */
		__list_del_entry(&info->head);
		}

		/**
		* gcov_info_within_module - check if a profiling data set belongs to a module
		* @info: profiling data set
		* @mod: module
		*
		* Returns true if profiling data belongs module, false otherwise.
		*/
		bool gcov_info_within_module(struct gcov_info info, struct module mod)
		{
		return within_module((unsigned long)info->filename, mod);
		}

		/* Symbolic links to be created for each profiling data file. */
		const struct gcov_link gcov_link[] = {
		{ OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
		{ 0, NULL},
		};

		/**
		* gcov_info_reset - reset profiling data to zero
		* @info: profiling data set
		*/
		void gcov_info_reset(struct gcov_info *info)
		{
		struct gcov_fn_info *fn;

		list_for_each_entry(fn, &info->functions, head)
		memset(fn->counters, 0,
		sizeof(fn->counters[0]) * fn->num_counters);
		}

		/**
		* gcov_info_is_compatible - check if profiling data can be added
		* @info1: first profiling data set
		* @info2: second profiling data set
		*
		* Returns non-zero if profiling data can be added, zero otherwise.
		*/
		int gcov_info_is_compatible(struct gcov_info info1, struct gcov_info info2)
		{
		struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null(
		&info1->functions, struct gcov_fn_info, head);
		struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null(
		&info2->functions, struct gcov_fn_info, head);

		if (info1->checksum != info2->checksum)
		return false;
		if (!fn_ptr1)
		return fn_ptr1 == fn_ptr2;
		while (!list_is_last(&fn_ptr1->head, &info1->functions) &&
		!list_is_last(&fn_ptr2->head, &info2->functions)) {
		if (fn_ptr1->checksum != fn_ptr2->checksum)
		return false;
		if (fn_ptr1->use_extra_checksum != fn_ptr2->use_extra_checksum)
		return false;
		if (fn_ptr1->use_extra_checksum &&
		fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
		return false;
		fn_ptr1 = list_next_entry(fn_ptr1, head);
		fn_ptr2 = list_next_entry(fn_ptr2, head);
		}
		return list_is_last(&fn_ptr1->head, &info1->functions) &&
		list_is_last(&fn_ptr2->head, &info2->functions);
		}

		/**
		* gcov_info_add - add up profiling data
		* @dest: profiling data set to which data is added
		* @source: profiling data set which is added
		*
		* Adds profiling counts of @source to @dest.
		*/
		void gcov_info_add(struct gcov_info dst, struct gcov_info src)
		{
		struct gcov_fn_info *dfn_ptr;
		struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions,
		struct gcov_fn_info, head);

		list_for_each_entry(dfn_ptr, &dst->functions, head) {
		u32 i;

		for (i = 0; i < sfn_ptr->num_counters; i++)
		dfn_ptr->counters[i] += sfn_ptr->counters[i];
		}
		}

		static struct gcov_fn_info gcov_fn_info_dup(struct gcov_fn_info fn)
		{
		size_t cv_size; /* counter values size */
		struct gcov_fn_info fn_dup = kmemdup(fn, sizeof(fn),
		GFP_KERNEL);
		if (!fn_dup)
		return NULL;
		INIT_LIST_HEAD(&fn_dup->head);

		fn_dup->function_name = kstrdup(fn->function_name, GFP_KERNEL);
		if (!fn_dup->function_name)
		goto err_name;

		cv_size = fn->num_counters * sizeof(fn->counters[0]);
		fn_dup->counters = vmalloc(cv_size);
		if (!fn_dup->counters)
		goto err_counters;
		memcpy(fn_dup->counters, fn->counters, cv_size);

		return fn_dup;

		err_counters:
		kfree(fn_dup->function_name);
		err_name:
		kfree(fn_dup);
		return NULL;
		}

		/**
		* gcov_info_dup - duplicate profiling data set
		* @info: profiling data set to duplicate
		*
		* Return newly allocated duplicate on success, %NULL on error.
		*/
		struct gcov_info gcov_info_dup(struct gcov_info info)
		{
		struct gcov_info *dup;
		struct gcov_fn_info *fn;

		dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
		if (!dup)
		return NULL;
		INIT_LIST_HEAD(&dup->head);
		INIT_LIST_HEAD(&dup->functions);
		dup->filename = kstrdup(info->filename, GFP_KERNEL);
		if (!dup->filename)
		goto err;

		list_for_each_entry(fn, &info->functions, head) {
		struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn);

		if (!fn_dup)
		goto err;
		list_add_tail(&fn_dup->head, &dup->functions);
		}

		return dup;

		err:
		gcov_info_free(dup);
		return NULL;
		}

		/**
		* gcov_info_free - release memory for profiling data set duplicate
		* @info: profiling data set duplicate to free
		*/
		void gcov_info_free(struct gcov_info *info)
		{
		struct gcov_fn_info fn, tmp;

		list_for_each_entry_safe(fn, tmp, &info->functions, head) {
		kfree(fn->function_name);
		vfree(fn->counters);
		list_del(&fn->head);
		kfree(fn);
		}
		kfree(info->filename);
		kfree(info);
		}

		#define ITER_STRIDE PAGE_SIZE

		/**
		* struct gcov_iterator - specifies current file position in logical records
		* @info: associated profiling data
		* @buffer: buffer containing file data
		* @size: size of buffer
		* @pos: current position in file
		*/
		struct gcov_iterator {
		struct gcov_info *info;
		void *buffer;
		size_t size;
		loff_t pos;
		};

		/**
		* store_gcov_u32 - store 32 bit number in gcov format to buffer
		* @buffer: target buffer or NULL
		* @off: offset into the buffer
		* @v: value to be stored
		*
		* Number format defined by gcc: numbers are recorded in the 32 bit
		* unsigned binary form of the endianness of the machine generating the
		* file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
		* store anything.
		*/
		static size_t store_gcov_u32(void *buffer, size_t off, u32 v)
		{
		u32 *data;

		if (buffer) {
		data = buffer + off;
		*data = v;
		}

		return sizeof(*data);
		}

		/**
		* store_gcov_u64 - store 64 bit number in gcov format to buffer
		* @buffer: target buffer or NULL
		* @off: offset into the buffer
		* @v: value to be stored
		*
		* Number format defined by gcc: numbers are recorded in the 32 bit
		* unsigned binary form of the endianness of the machine generating the
		* file. 64 bit numbers are stored as two 32 bit numbers, the low part
		* first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
		* anything.
		*/
		static size_t store_gcov_u64(void *buffer, size_t off, u64 v)
		{
		u32 *data;

		if (buffer) {
		data = buffer + off;

		data[0] = (v & 0xffffffffUL);
		data[1] = (v >> 32);
		}

		return sizeof(data) 2;
		}

		/**
		* convert_to_gcda - convert profiling data set to gcda file format
		* @buffer: the buffer to store file data or %NULL if no data should be stored
		* @info: profiling data set to be converted
		*
		* Returns the number of bytes that were/would have been stored into the buffer.
		*/
		static size_t convert_to_gcda(char buffer, struct gcov_info info)
		{
		struct gcov_fn_info *fi_ptr;
		size_t pos = 0;

		/* File header. */
		pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
		pos += store_gcov_u32(buffer, pos, info->version);
		pos += store_gcov_u32(buffer, pos, info->checksum);

		list_for_each_entry(fi_ptr, &info->functions, head) {
		u32 i;
		u32 len = 2;

		if (fi_ptr->use_extra_checksum)
		len++;

		pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
		pos += store_gcov_u32(buffer, pos, len);
		pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
		pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
		if (fi_ptr->use_extra_checksum)
		pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);

		pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE);
		pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2);
		for (i = 0; i < fi_ptr->num_counters; i++)
		pos += store_gcov_u64(buffer, pos, fi_ptr->counters[i]);
		}

		return pos;
		}

		/**
		* gcov_iter_new - allocate and initialize profiling data iterator
		* @info: profiling data set to be iterated
		*
		* Return file iterator on success, %NULL otherwise.
		*/
		struct gcov_iterator gcov_iter_new(struct gcov_info info)
		{
		struct gcov_iterator *iter;

		iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL);
		if (!iter)
		goto err_free;

		iter->info = info;
		/* Dry-run to get the actual buffer size. */
		iter->size = convert_to_gcda(NULL, info);
		iter->buffer = vmalloc(iter->size);
		if (!iter->buffer)
		goto err_free;

		convert_to_gcda(iter->buffer, info);

		return iter;

		err_free:
		kfree(iter);
		return NULL;
		}


		/**
		* gcov_iter_get_info - return profiling data set for given file iterator
		* @iter: file iterator
		*/
		void gcov_iter_free(struct gcov_iterator *iter)
		{
		vfree(iter->buffer);
		kfree(iter);
		}

		/**
		* gcov_iter_get_info - return profiling data set for given file iterator
		* @iter: file iterator
		*/
		struct gcov_info gcov_iter_get_info(struct gcov_iterator iter)
		{
		return iter->info;
		}

		/**
		* gcov_iter_start - reset file iterator to starting position
		* @iter: file iterator
		*/
		void gcov_iter_start(struct gcov_iterator *iter)
		{
		iter->pos = 0;
		}

		/**
		* gcov_iter_next - advance file iterator to next logical record
		* @iter: file iterator
		*
		* Return zero if new position is valid, non-zero if iterator has reached end.
		*/
		int gcov_iter_next(struct gcov_iterator *iter)
		{
		if (iter->pos < iter->size)
		iter->pos += ITER_STRIDE;

		if (iter->pos >= iter->size)
		return -EINVAL;

		return 0;
		}

		/**
		* gcov_iter_write - write data for current pos to seq_file
		* @iter: file iterator
		* @seq: seq_file handle
		*
		* Return zero on success, non-zero otherwise.
		*/
		int gcov_iter_write(struct gcov_iterator iter, struct seq_file seq)
		{
		size_t len;

		if (iter->pos >= iter->size)
		return -EINVAL;

		len = ITER_STRIDE;
		if (iter->pos + len > iter->size)
		len = iter->size - iter->pos;

		seq_write(seq, iter->buffer + iter->pos, len);

		return 0;
		}

kernel/gcov/gcc_3_4.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -137,6 +137,18 @@ void gcov_info_unlink(struct gcov_info prev, struct gcov_info info)
		gcov_info_head = info->next;
		}

		/**
		* gcov_info_within_module - check if a profiling data set belongs to a module
		* @info: profiling data set
		* @mod: module
		*
		* Returns true if profiling data belongs module, false otherwise.
		*/
		bool gcov_info_within_module(struct gcov_info info, struct module mod)
		{
		return within_module((unsigned long)info, mod);
		}

		/* Symbolic links to be created for each profiling data file. */
		const struct gcov_link gcov_link[] = {
		{ OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */

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