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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 13:43:55 +08:00
linux-next/tools/perf/util/llvm-utils.c
Arnaldo Carvalho de Melo cb76371441 perf llvm: Allow passing options to llc in addition to clang
The newly added 'llvm.opts' variable allows passing options directly to
llc, like needed to get sane DWARF in BPF ELF debug sections:

With:

  [root@seventh perf]# cat ~/.perfconfig
  [llvm]
	  dump-obj = true
	clang-opt = -g
  [root@seventh perf]#

We get:

  [root@seventh perf]# perf trace -e tools/perf/examples/bpf/hello.c cat /etc/passwd > /dev/null
  LLVM: dumping tools/perf/examples/bpf/hello.o
       0.000 __bpf_stdout__:Hello, world
       0.015 __bpf_stdout__:Hello, world
       0.187 __bpf_stdout__:Hello, world
  [root@seventh perf]# pahole tools/perf/examples/bpf/hello.o
  struct clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c) {
	  clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /*     0     4 */
	  clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /*     4     4 */
	  clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /*     8     4 */
	  clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /*    12     4 */
	  clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /*    16     4 */
	  clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /*    20     4 */
	  clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /*    24     4 */

	  /* size: 28, cachelines: 1, members: 7 */
	  /* last cacheline: 28 bytes */
  };
  [root@seventh perf]#

Adding these options to be passed to llvm's llc:

  [root@seventh perf]# cat ~/.perfconfig
  [llvm]
	  dump-obj = true
	  clang-opt = -g
	  opts = -mattr=dwarfris
  [root@seventh perf]#

We get sane output:

  [root@seventh perf]# perf trace -e tools/perf/examples/bpf/hello.c cat /etc/passwd > /dev/null
  LLVM: dumping tools/perf/examples/bpf/hello.o
       0.000 __bpf_stdout__:Hello, world
       0.015 __bpf_stdout__:Hello, world
       0.185 __bpf_stdout__:Hello, world
  [root@seventh perf]# pahole tools/perf/examples/bpf/hello.o
  struct bpf_map {
	  unsigned int               type;                 /*     0     4 */
	  unsigned int               key_size;             /*     4     4 */
	  unsigned int               value_size;           /*     8     4 */
	  unsigned int               max_entries;          /*    12     4 */
	  unsigned int               map_flags;            /*    16     4 */
	  unsigned int               inner_map_idx;        /*    20     4 */
	  unsigned int               numa_node;            /*    24     4 */

	  /* size: 28, cachelines: 1, members: 7 */
	  /* last cacheline: 28 bytes */
  };
  [root@seventh perf]#

Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>,
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-0lrwmrip4dru1651rm8xa7tq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-08-20 08:54:58 -03:00

578 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015, Huawei Inc.
*/
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/err.h>
#include "debug.h"
#include "llvm-utils.h"
#include "config.h"
#include "util.h"
#include <sys/wait.h>
#include <subcmd/exec-cmd.h>
#define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
"$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
"-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
"$CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS " \
"-Wno-unused-value -Wno-pointer-sign " \
"-working-directory $WORKING_DIR " \
"-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
struct llvm_param llvm_param = {
.clang_path = "clang",
.llc_path = "llc",
.clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
.clang_opt = NULL,
.opts = NULL,
.kbuild_dir = NULL,
.kbuild_opts = NULL,
.user_set_param = false,
};
int perf_llvm_config(const char *var, const char *value)
{
if (!strstarts(var, "llvm."))
return 0;
var += sizeof("llvm.") - 1;
if (!strcmp(var, "clang-path"))
llvm_param.clang_path = strdup(value);
else if (!strcmp(var, "clang-bpf-cmd-template"))
llvm_param.clang_bpf_cmd_template = strdup(value);
else if (!strcmp(var, "clang-opt"))
llvm_param.clang_opt = strdup(value);
else if (!strcmp(var, "kbuild-dir"))
llvm_param.kbuild_dir = strdup(value);
else if (!strcmp(var, "kbuild-opts"))
llvm_param.kbuild_opts = strdup(value);
else if (!strcmp(var, "dump-obj"))
llvm_param.dump_obj = !!perf_config_bool(var, value);
else if (!strcmp(var, "opts"))
llvm_param.opts = strdup(value);
else {
pr_debug("Invalid LLVM config option: %s\n", value);
return -1;
}
llvm_param.user_set_param = true;
return 0;
}
static int
search_program(const char *def, const char *name,
char *output)
{
char *env, *path, *tmp = NULL;
char buf[PATH_MAX];
int ret;
output[0] = '\0';
if (def && def[0] != '\0') {
if (def[0] == '/') {
if (access(def, F_OK) == 0) {
strlcpy(output, def, PATH_MAX);
return 0;
}
} else if (def[0] != '\0')
name = def;
}
env = getenv("PATH");
if (!env)
return -1;
env = strdup(env);
if (!env)
return -1;
ret = -ENOENT;
path = strtok_r(env, ":", &tmp);
while (path) {
scnprintf(buf, sizeof(buf), "%s/%s", path, name);
if (access(buf, F_OK) == 0) {
strlcpy(output, buf, PATH_MAX);
ret = 0;
break;
}
path = strtok_r(NULL, ":", &tmp);
}
free(env);
return ret;
}
#define READ_SIZE 4096
static int
read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
{
int err = 0;
void *buf = NULL;
FILE *file = NULL;
size_t read_sz = 0, buf_sz = 0;
char serr[STRERR_BUFSIZE];
file = popen(cmd, "r");
if (!file) {
pr_err("ERROR: unable to popen cmd: %s\n",
str_error_r(errno, serr, sizeof(serr)));
return -EINVAL;
}
while (!feof(file) && !ferror(file)) {
/*
* Make buf_sz always have obe byte extra space so we
* can put '\0' there.
*/
if (buf_sz - read_sz < READ_SIZE + 1) {
void *new_buf;
buf_sz = read_sz + READ_SIZE + 1;
new_buf = realloc(buf, buf_sz);
if (!new_buf) {
pr_err("ERROR: failed to realloc memory\n");
err = -ENOMEM;
goto errout;
}
buf = new_buf;
}
read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
}
if (buf_sz - read_sz < 1) {
pr_err("ERROR: internal error\n");
err = -EINVAL;
goto errout;
}
if (ferror(file)) {
pr_err("ERROR: error occurred when reading from pipe: %s\n",
str_error_r(errno, serr, sizeof(serr)));
err = -EIO;
goto errout;
}
err = WEXITSTATUS(pclose(file));
file = NULL;
if (err) {
err = -EINVAL;
goto errout;
}
/*
* If buf is string, give it terminal '\0' to make our life
* easier. If buf is not string, that '\0' is out of space
* indicated by read_sz so caller won't even notice it.
*/
((char *)buf)[read_sz] = '\0';
if (!p_buf)
free(buf);
else
*p_buf = buf;
if (p_read_sz)
*p_read_sz = read_sz;
return 0;
errout:
if (file)
pclose(file);
free(buf);
if (p_buf)
*p_buf = NULL;
if (p_read_sz)
*p_read_sz = 0;
return err;
}
static inline void
force_set_env(const char *var, const char *value)
{
if (value) {
setenv(var, value, 1);
pr_debug("set env: %s=%s\n", var, value);
} else {
unsetenv(var);
pr_debug("unset env: %s\n", var);
}
}
static void
version_notice(void)
{
pr_err(
" \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
" \tYou may want to try git trunk:\n"
" \t\tgit clone http://llvm.org/git/llvm.git\n"
" \t\t and\n"
" \t\tgit clone http://llvm.org/git/clang.git\n\n"
" \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
" \tdebian/ubuntu:\n"
" \t\thttp://llvm.org/apt\n\n"
" \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
" \toption in [llvm] section of ~/.perfconfig to:\n\n"
" \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
" \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
" \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
" \t(Replace /path/to/llc with path to your llc)\n\n"
);
}
static int detect_kbuild_dir(char **kbuild_dir)
{
const char *test_dir = llvm_param.kbuild_dir;
const char *prefix_dir = "";
const char *suffix_dir = "";
char *autoconf_path;
int err;
if (!test_dir) {
/* _UTSNAME_LENGTH is 65 */
char release[128];
err = fetch_kernel_version(NULL, release,
sizeof(release));
if (err)
return -EINVAL;
test_dir = release;
prefix_dir = "/lib/modules/";
suffix_dir = "/build";
}
err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
prefix_dir, test_dir, suffix_dir);
if (err < 0)
return -ENOMEM;
if (access(autoconf_path, R_OK) == 0) {
free(autoconf_path);
err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
suffix_dir);
if (err < 0)
return -ENOMEM;
return 0;
}
free(autoconf_path);
return -ENOENT;
}
static const char *kinc_fetch_script =
"#!/usr/bin/env sh\n"
"if ! test -d \"$KBUILD_DIR\"\n"
"then\n"
" exit 1\n"
"fi\n"
"if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
"then\n"
" exit 1\n"
"fi\n"
"TMPDIR=`mktemp -d`\n"
"if test -z \"$TMPDIR\"\n"
"then\n"
" exit 1\n"
"fi\n"
"cat << EOF > $TMPDIR/Makefile\n"
"obj-y := dummy.o\n"
"\\$(obj)/%.o: \\$(src)/%.c\n"
"\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
"EOF\n"
"touch $TMPDIR/dummy.c\n"
"make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
"RET=$?\n"
"rm -rf $TMPDIR\n"
"exit $RET\n";
void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
{
static char *saved_kbuild_dir;
static char *saved_kbuild_include_opts;
int err;
if (!kbuild_dir || !kbuild_include_opts)
return;
*kbuild_dir = NULL;
*kbuild_include_opts = NULL;
if (saved_kbuild_dir && saved_kbuild_include_opts &&
!IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
*kbuild_dir = strdup(saved_kbuild_dir);
*kbuild_include_opts = strdup(saved_kbuild_include_opts);
if (*kbuild_dir && *kbuild_include_opts)
return;
zfree(kbuild_dir);
zfree(kbuild_include_opts);
/*
* Don't fall through: it may breaks saved_kbuild_dir and
* saved_kbuild_include_opts if detect them again when
* memory is low.
*/
return;
}
if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
pr_debug("Skip kbuild options detection.\n");
goto errout;
}
err = detect_kbuild_dir(kbuild_dir);
if (err) {
pr_warning(
"WARNING:\tunable to get correct kernel building directory.\n"
"Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
" \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
" \tdetection.\n\n");
goto errout;
}
pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
force_set_env("KBUILD_DIR", *kbuild_dir);
force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
err = read_from_pipe(kinc_fetch_script,
(void **)kbuild_include_opts,
NULL);
if (err) {
pr_warning(
"WARNING:\tunable to get kernel include directories from '%s'\n"
"Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
" \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
" \toption in [llvm] to \"\" to suppress this detection.\n\n",
*kbuild_dir);
free(*kbuild_dir);
*kbuild_dir = NULL;
goto errout;
}
pr_debug("include option is set to %s\n", *kbuild_include_opts);
saved_kbuild_dir = strdup(*kbuild_dir);
saved_kbuild_include_opts = strdup(*kbuild_include_opts);
if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
zfree(&saved_kbuild_dir);
zfree(&saved_kbuild_include_opts);
}
return;
errout:
saved_kbuild_dir = ERR_PTR(-EINVAL);
saved_kbuild_include_opts = ERR_PTR(-EINVAL);
}
int llvm__get_nr_cpus(void)
{
static int nr_cpus_avail = 0;
char serr[STRERR_BUFSIZE];
if (nr_cpus_avail > 0)
return nr_cpus_avail;
nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
if (nr_cpus_avail <= 0) {
pr_err(
"WARNING:\tunable to get available CPUs in this system: %s\n"
" \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
nr_cpus_avail = 128;
}
return nr_cpus_avail;
}
void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
{
char *obj_path = strdup(path);
FILE *fp;
char *p;
if (!obj_path) {
pr_warning("WARNING: Not enough memory, skip object dumping\n");
return;
}
p = strrchr(obj_path, '.');
if (!p || (strcmp(p, ".c") != 0)) {
pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
obj_path);
goto out;
}
p[1] = 'o';
fp = fopen(obj_path, "wb");
if (!fp) {
pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
obj_path, strerror(errno));
goto out;
}
pr_info("LLVM: dumping %s\n", obj_path);
if (fwrite(obj_buf, size, 1, fp) != 1)
pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
obj_path, strerror(errno));
fclose(fp);
out:
free(obj_path);
}
int llvm__compile_bpf(const char *path, void **p_obj_buf,
size_t *p_obj_buf_sz)
{
size_t obj_buf_sz;
void *obj_buf = NULL;
int err, nr_cpus_avail;
unsigned int kernel_version;
char linux_version_code_str[64];
const char *clang_opt = llvm_param.clang_opt;
char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
char serr[STRERR_BUFSIZE];
char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
*perf_bpf_include_opts = NULL;
const char *template = llvm_param.clang_bpf_cmd_template;
char *pipe_template = NULL;
const char *opts = llvm_param.opts;
char *command_echo = NULL, *command_out;
char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
if (path[0] != '-' && realpath(path, abspath) == NULL) {
err = errno;
pr_err("ERROR: problems with path %s: %s\n",
path, str_error_r(err, serr, sizeof(serr)));
return -err;
}
if (!template)
template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
err = search_program(llvm_param.clang_path,
"clang", clang_path);
if (err) {
pr_err(
"ERROR:\tunable to find clang.\n"
"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
" \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
version_notice();
return -ENOENT;
}
/*
* This is an optional work. Even it fail we can continue our
* work. Needn't to check error return.
*/
llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
nr_cpus_avail = llvm__get_nr_cpus();
snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
nr_cpus_avail);
if (fetch_kernel_version(&kernel_version, NULL, 0))
kernel_version = 0;
snprintf(linux_version_code_str, sizeof(linux_version_code_str),
"0x%x", kernel_version);
if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
goto errout;
force_set_env("NR_CPUS", nr_cpus_avail_str);
force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
force_set_env("CLANG_EXEC", clang_path);
force_set_env("CLANG_OPTIONS", clang_opt);
force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
force_set_env("WORKING_DIR", kbuild_dir ? : ".");
if (opts) {
err = search_program(llvm_param.llc_path, "llc", llc_path);
if (err) {
pr_err("ERROR:\tunable to find llc.\n"
"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
" \tand 'llc-path' option in [llvm] section of ~/.perfconfig.\n");
version_notice();
goto errout;
}
if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
template, llc_path, opts) < 0) {
pr_err("ERROR:\tnot enough memory to setup command line\n");
goto errout;
}
template = pipe_template;
}
/*
* Since we may reset clang's working dir, path of source file
* should be transferred into absolute path, except we want
* stdin to be source file (testing).
*/
force_set_env("CLANG_SOURCE",
(path[0] == '-') ? path : abspath);
pr_debug("llvm compiling command template: %s\n", template);
if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
goto errout;
err = read_from_pipe(command_echo, (void **) &command_out, NULL);
if (err)
goto errout;
pr_debug("llvm compiling command : %s\n", command_out);
err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
if (err) {
pr_err("ERROR:\tunable to compile %s\n", path);
pr_err("Hint:\tCheck error message shown above.\n");
pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
pr_err(" \twith proper -I and -D options.\n");
goto errout;
}
free(command_echo);
free(command_out);
free(kbuild_dir);
free(kbuild_include_opts);
free(perf_bpf_include_opts);
free(perf_include_dir);
if (!p_obj_buf)
free(obj_buf);
else
*p_obj_buf = obj_buf;
if (p_obj_buf_sz)
*p_obj_buf_sz = obj_buf_sz;
return 0;
errout:
free(command_echo);
free(kbuild_dir);
free(kbuild_include_opts);
free(obj_buf);
free(perf_bpf_include_opts);
free(perf_include_dir);
free(pipe_template);
if (p_obj_buf)
*p_obj_buf = NULL;
if (p_obj_buf_sz)
*p_obj_buf_sz = 0;
return err;
}
int llvm__search_clang(void)
{
char clang_path[PATH_MAX];
return search_program(llvm_param.clang_path, "clang", clang_path);
}