2 * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
3 * Copyright (C) 2015, Huawei Inc.
10 #include <linux/err.h>
12 #include "llvm-utils.h"
16 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
17 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
18 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
19 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \
20 "-Wno-unused-value -Wno-pointer-sign " \
21 "-working-directory $WORKING_DIR " \
22 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
24 struct llvm_param llvm_param = {
25 .clang_path = "clang",
26 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
30 .user_set_param = false,
33 int perf_llvm_config(const char *var, const char *value)
35 if (prefixcmp(var, "llvm."))
37 var += sizeof("llvm.") - 1;
39 if (!strcmp(var, "clang-path"))
40 llvm_param.clang_path = strdup(value);
41 else if (!strcmp(var, "clang-bpf-cmd-template"))
42 llvm_param.clang_bpf_cmd_template = strdup(value);
43 else if (!strcmp(var, "clang-opt"))
44 llvm_param.clang_opt = strdup(value);
45 else if (!strcmp(var, "kbuild-dir"))
46 llvm_param.kbuild_dir = strdup(value);
47 else if (!strcmp(var, "kbuild-opts"))
48 llvm_param.kbuild_opts = strdup(value);
49 else if (!strcmp(var, "dump-obj"))
50 llvm_param.dump_obj = !!perf_config_bool(var, value);
53 llvm_param.user_set_param = true;
58 search_program(const char *def, const char *name,
61 char *env, *path, *tmp = NULL;
66 if (def && def[0] != '\0') {
68 if (access(def, F_OK) == 0) {
69 strlcpy(output, def, PATH_MAX);
72 } else if (def[0] != '\0')
84 path = strtok_r(env, ":", &tmp);
86 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
87 if (access(buf, F_OK) == 0) {
88 strlcpy(output, buf, PATH_MAX);
92 path = strtok_r(NULL, ":", &tmp);
99 #define READ_SIZE 4096
101 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
106 size_t read_sz = 0, buf_sz = 0;
107 char serr[STRERR_BUFSIZE];
109 file = popen(cmd, "r");
111 pr_err("ERROR: unable to popen cmd: %s\n",
112 str_error_r(errno, serr, sizeof(serr)));
116 while (!feof(file) && !ferror(file)) {
118 * Make buf_sz always have obe byte extra space so we
119 * can put '\0' there.
121 if (buf_sz - read_sz < READ_SIZE + 1) {
124 buf_sz = read_sz + READ_SIZE + 1;
125 new_buf = realloc(buf, buf_sz);
128 pr_err("ERROR: failed to realloc memory\n");
135 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
138 if (buf_sz - read_sz < 1) {
139 pr_err("ERROR: internal error\n");
145 pr_err("ERROR: error occurred when reading from pipe: %s\n",
146 str_error_r(errno, serr, sizeof(serr)));
151 err = WEXITSTATUS(pclose(file));
159 * If buf is string, give it terminal '\0' to make our life
160 * easier. If buf is not string, that '\0' is out of space
161 * indicated by read_sz so caller won't even notice it.
163 ((char *)buf)[read_sz] = '\0';
171 *p_read_sz = read_sz;
186 force_set_env(const char *var, const char *value)
189 setenv(var, value, 1);
190 pr_debug("set env: %s=%s\n", var, value);
193 pr_debug("unset env: %s\n", var);
201 " \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
202 " \tYou may want to try git trunk:\n"
203 " \t\tgit clone http://llvm.org/git/llvm.git\n"
205 " \t\tgit clone http://llvm.org/git/clang.git\n\n"
206 " \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
207 " \tdebian/ubuntu:\n"
208 " \t\thttp://llvm.org/apt\n\n"
209 " \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
210 " \toption in [llvm] section of ~/.perfconfig to:\n\n"
211 " \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
212 " \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
213 " \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
214 " \t(Replace /path/to/llc with path to your llc)\n\n"
218 static int detect_kbuild_dir(char **kbuild_dir)
220 const char *test_dir = llvm_param.kbuild_dir;
221 const char *prefix_dir = "";
222 const char *suffix_dir = "";
229 /* _UTSNAME_LENGTH is 65 */
232 err = fetch_kernel_version(NULL, release,
238 prefix_dir = "/lib/modules/";
239 suffix_dir = "/build";
242 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
243 prefix_dir, test_dir, suffix_dir);
247 if (access(autoconf_path, R_OK) == 0) {
250 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
260 static const char *kinc_fetch_script =
261 "#!/usr/bin/env sh\n"
262 "if ! test -d \"$KBUILD_DIR\"\n"
266 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
270 "TMPDIR=`mktemp -d`\n"
271 "if test -z \"$TMPDIR\"\n"
275 "cat << EOF > $TMPDIR/Makefile\n"
277 "\\$(obj)/%.o: \\$(src)/%.c\n"
278 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
280 "touch $TMPDIR/dummy.c\n"
281 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
286 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
288 static char *saved_kbuild_dir;
289 static char *saved_kbuild_include_opts;
292 if (!kbuild_dir || !kbuild_include_opts)
296 *kbuild_include_opts = NULL;
298 if (saved_kbuild_dir && saved_kbuild_include_opts &&
299 !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
300 *kbuild_dir = strdup(saved_kbuild_dir);
301 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
303 if (*kbuild_dir && *kbuild_include_opts)
307 zfree(kbuild_include_opts);
309 * Don't fall through: it may breaks saved_kbuild_dir and
310 * saved_kbuild_include_opts if detect them again when
316 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
317 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
318 pr_debug("Skip kbuild options detection.\n");
322 err = detect_kbuild_dir(kbuild_dir);
325 "WARNING:\tunable to get correct kernel building directory.\n"
326 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
327 " \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
328 " \tdetection.\n\n");
332 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
333 force_set_env("KBUILD_DIR", *kbuild_dir);
334 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
335 err = read_from_pipe(kinc_fetch_script,
336 (void **)kbuild_include_opts,
340 "WARNING:\tunable to get kernel include directories from '%s'\n"
341 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
342 " \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
343 " \toption in [llvm] to \"\" to suppress this detection.\n\n",
351 pr_debug("include option is set to %s\n", *kbuild_include_opts);
353 saved_kbuild_dir = strdup(*kbuild_dir);
354 saved_kbuild_include_opts = strdup(*kbuild_include_opts);
356 if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
357 zfree(&saved_kbuild_dir);
358 zfree(&saved_kbuild_include_opts);
362 saved_kbuild_dir = ERR_PTR(-EINVAL);
363 saved_kbuild_include_opts = ERR_PTR(-EINVAL);
366 int llvm__get_nr_cpus(void)
368 static int nr_cpus_avail = 0;
369 char serr[STRERR_BUFSIZE];
371 if (nr_cpus_avail > 0)
372 return nr_cpus_avail;
374 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
375 if (nr_cpus_avail <= 0) {
377 "WARNING:\tunable to get available CPUs in this system: %s\n"
378 " \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
381 return nr_cpus_avail;
384 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
386 char *obj_path = strdup(path);
391 pr_warning("WARNING: Not enough memory, skip object dumping\n");
395 p = strrchr(obj_path, '.');
396 if (!p || (strcmp(p, ".c") != 0)) {
397 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
403 fp = fopen(obj_path, "wb");
405 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
406 obj_path, strerror(errno));
410 pr_info("LLVM: dumping %s\n", obj_path);
411 if (fwrite(obj_buf, size, 1, fp) != 1)
412 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
413 obj_path, strerror(errno));
419 int llvm__compile_bpf(const char *path, void **p_obj_buf,
420 size_t *p_obj_buf_sz)
423 void *obj_buf = NULL;
424 int err, nr_cpus_avail;
425 unsigned int kernel_version;
426 char linux_version_code_str[64];
427 const char *clang_opt = llvm_param.clang_opt;
428 char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
429 char serr[STRERR_BUFSIZE];
430 char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
431 const char *template = llvm_param.clang_bpf_cmd_template;
433 if (path[0] != '-' && realpath(path, abspath) == NULL) {
435 pr_err("ERROR: problems with path %s: %s\n",
436 path, str_error_r(err, serr, sizeof(serr)));
441 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
443 err = search_program(llvm_param.clang_path,
444 "clang", clang_path);
447 "ERROR:\tunable to find clang.\n"
448 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
449 " \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
455 * This is an optional work. Even it fail we can continue our
456 * work. Needn't to check error return.
458 llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
460 nr_cpus_avail = llvm__get_nr_cpus();
461 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
464 if (fetch_kernel_version(&kernel_version, NULL, 0))
467 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
468 "0x%x", kernel_version);
470 force_set_env("NR_CPUS", nr_cpus_avail_str);
471 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
472 force_set_env("CLANG_EXEC", clang_path);
473 force_set_env("CLANG_OPTIONS", clang_opt);
474 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
475 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
478 * Since we may reset clang's working dir, path of source file
479 * should be transferred into absolute path, except we want
480 * stdin to be source file (testing).
482 force_set_env("CLANG_SOURCE",
483 (path[0] == '-') ? path : abspath);
485 pr_debug("llvm compiling command template: %s\n", template);
486 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
488 pr_err("ERROR:\tunable to compile %s\n", path);
489 pr_err("Hint:\tCheck error message shown above.\n");
490 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
491 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
492 pr_err(" \twith proper -I and -D options.\n");
497 free(kbuild_include_opts);
502 *p_obj_buf = obj_buf;
505 *p_obj_buf_sz = obj_buf_sz;
509 free(kbuild_include_opts);
518 int llvm__search_clang(void)
520 char clang_path[PATH_MAX];
522 return search_program(llvm_param.clang_path, "clang", clang_path);