- 根目录:
- tools
- perf
- util
- llvm-utils.c
/*
* Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015, Huawei Inc.
*/
#include <stdio.h>
#include "util.h"
#include "debug.h"
#include "llvm-utils.h"
#include "cache.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 " \
"-Wno-unused-value -Wno-pointer-sign " \
"-working-directory $WORKING_DIR " \
"-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
struct llvm_param llvm_param = {
.clang_path = "clang",
.clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
.clang_opt = NULL,
.kbuild_dir = NULL,
.kbuild_opts = NULL,
.user_set_param = false,
};
int perf_llvm_config(const char *var, const char *value)
{
if (prefixcmp(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
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;
file = popen(cmd, "r");
if (!file) {
pr_err("ERROR: unable to popen cmd: %s\n",
strerror(errno));
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",
strerror(errno));
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 \\\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";
static inline void
get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
{
int err;
if (!kbuild_dir || !kbuild_include_opts)
return;
*kbuild_dir = NULL;
*kbuild_include_opts = NULL;
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");
return;
}
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");
return;
}
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;
return;
}
pr_debug("include option is set to %s\n", *kbuild_include_opts);
}
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], nr_cpus_avail_str[64];
char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
const char *template = llvm_param.clang_bpf_cmd_template;
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.
*/
get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
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", strerror(errno));
nr_cpus_avail = 128;
}
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);
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("WORKING_DIR", kbuild_dir ? : ".");
/*
* 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 :
make_nonrelative_path(path));
pr_debug("llvm compiling command template: %s\n", template);
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(kbuild_dir);
free(kbuild_include_opts);
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(kbuild_dir);
free(kbuild_include_opts);
free(obj_buf);
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);
}