1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
4 * Copyright (C) 2015, Huawei Inc.
11 #include <linux/err.h>
12 #include <linux/zalloc.h>
14 #include "llvm-utils.h"
18 #include <subcmd/exec-cmd.h>
20 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
21 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
22 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
23 "$CLANG_OPTIONS $PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \
24 "-Wno-unused-value -Wno-pointer-sign " \
25 "-working-directory $WORKING_DIR " \
26 "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
28 struct llvm_param llvm_param = {
29 .clang_path = "clang",
31 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
36 .user_set_param = false,
39 int perf_llvm_config(const char *var, const char *value)
41 if (!strstarts(var, "llvm."))
43 var += sizeof("llvm.") - 1;
45 if (!strcmp(var, "clang-path"))
46 llvm_param.clang_path = strdup(value);
47 else if (!strcmp(var, "clang-bpf-cmd-template"))
48 llvm_param.clang_bpf_cmd_template = strdup(value);
49 else if (!strcmp(var, "clang-opt"))
50 llvm_param.clang_opt = strdup(value);
51 else if (!strcmp(var, "kbuild-dir"))
52 llvm_param.kbuild_dir = strdup(value);
53 else if (!strcmp(var, "kbuild-opts"))
54 llvm_param.kbuild_opts = strdup(value);
55 else if (!strcmp(var, "dump-obj"))
56 llvm_param.dump_obj = !!perf_config_bool(var, value);
57 else if (!strcmp(var, "opts"))
58 llvm_param.opts = strdup(value);
60 pr_debug("Invalid LLVM config option: %s\n", value);
63 llvm_param.user_set_param = true;
68 search_program(const char *def, const char *name,
71 char *env, *path, *tmp = NULL;
76 if (def && def[0] != '\0') {
78 if (access(def, F_OK) == 0) {
79 strlcpy(output, def, PATH_MAX);
82 } else if (def[0] != '\0')
94 path = strtok_r(env, ":", &tmp);
96 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
97 if (access(buf, F_OK) == 0) {
98 strlcpy(output, buf, PATH_MAX);
102 path = strtok_r(NULL, ":", &tmp);
109 #define READ_SIZE 4096
111 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
116 size_t read_sz = 0, buf_sz = 0;
117 char serr[STRERR_BUFSIZE];
119 file = popen(cmd, "r");
121 pr_err("ERROR: unable to popen cmd: %s\n",
122 str_error_r(errno, serr, sizeof(serr)));
126 while (!feof(file) && !ferror(file)) {
128 * Make buf_sz always have obe byte extra space so we
129 * can put '\0' there.
131 if (buf_sz - read_sz < READ_SIZE + 1) {
134 buf_sz = read_sz + READ_SIZE + 1;
135 new_buf = realloc(buf, buf_sz);
138 pr_err("ERROR: failed to realloc memory\n");
145 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
148 if (buf_sz - read_sz < 1) {
149 pr_err("ERROR: internal error\n");
155 pr_err("ERROR: error occurred when reading from pipe: %s\n",
156 str_error_r(errno, serr, sizeof(serr)));
161 err = WEXITSTATUS(pclose(file));
169 * If buf is string, give it terminal '\0' to make our life
170 * easier. If buf is not string, that '\0' is out of space
171 * indicated by read_sz so caller won't even notice it.
173 ((char *)buf)[read_sz] = '\0';
181 *p_read_sz = read_sz;
196 force_set_env(const char *var, const char *value)
199 setenv(var, value, 1);
200 pr_debug("set env: %s=%s\n", var, value);
203 pr_debug("unset env: %s\n", var);
211 " \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
212 " \tYou may want to try git trunk:\n"
213 " \t\tgit clone http://llvm.org/git/llvm.git\n"
215 " \t\tgit clone http://llvm.org/git/clang.git\n\n"
216 " \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
217 " \tdebian/ubuntu:\n"
218 " \t\thttp://llvm.org/apt\n\n"
219 " \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
220 " \toption in [llvm] section of ~/.perfconfig to:\n\n"
221 " \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
222 " \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
223 " \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
224 " \t(Replace /path/to/llc with path to your llc)\n\n"
228 static int detect_kbuild_dir(char **kbuild_dir)
230 const char *test_dir = llvm_param.kbuild_dir;
231 const char *prefix_dir = "";
232 const char *suffix_dir = "";
239 /* _UTSNAME_LENGTH is 65 */
242 err = fetch_kernel_version(NULL, release,
248 prefix_dir = "/lib/modules/";
249 suffix_dir = "/build";
252 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
253 prefix_dir, test_dir, suffix_dir);
257 if (access(autoconf_path, R_OK) == 0) {
260 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
270 static const char *kinc_fetch_script =
271 "#!/usr/bin/env sh\n"
272 "if ! test -d \"$KBUILD_DIR\"\n"
276 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
280 "TMPDIR=`mktemp -d`\n"
281 "if test -z \"$TMPDIR\"\n"
285 "cat << EOF > $TMPDIR/Makefile\n"
287 "\\$(obj)/%.o: \\$(src)/%.c\n"
288 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
290 "touch $TMPDIR/dummy.c\n"
291 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
296 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
298 static char *saved_kbuild_dir;
299 static char *saved_kbuild_include_opts;
302 if (!kbuild_dir || !kbuild_include_opts)
306 *kbuild_include_opts = NULL;
308 if (saved_kbuild_dir && saved_kbuild_include_opts &&
309 !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
310 *kbuild_dir = strdup(saved_kbuild_dir);
311 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
313 if (*kbuild_dir && *kbuild_include_opts)
317 zfree(kbuild_include_opts);
319 * Don't fall through: it may breaks saved_kbuild_dir and
320 * saved_kbuild_include_opts if detect them again when
326 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
327 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
328 pr_debug("Skip kbuild options detection.\n");
332 err = detect_kbuild_dir(kbuild_dir);
335 "WARNING:\tunable to get correct kernel building directory.\n"
336 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
337 " \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
338 " \tdetection.\n\n");
342 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
343 force_set_env("KBUILD_DIR", *kbuild_dir);
344 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
345 err = read_from_pipe(kinc_fetch_script,
346 (void **)kbuild_include_opts,
350 "WARNING:\tunable to get kernel include directories from '%s'\n"
351 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
352 " \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
353 " \toption in [llvm] to \"\" to suppress this detection.\n\n",
360 pr_debug("include option is set to %s\n", *kbuild_include_opts);
362 saved_kbuild_dir = strdup(*kbuild_dir);
363 saved_kbuild_include_opts = strdup(*kbuild_include_opts);
365 if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
366 zfree(&saved_kbuild_dir);
367 zfree(&saved_kbuild_include_opts);
371 saved_kbuild_dir = ERR_PTR(-EINVAL);
372 saved_kbuild_include_opts = ERR_PTR(-EINVAL);
375 int llvm__get_nr_cpus(void)
377 static int nr_cpus_avail = 0;
378 char serr[STRERR_BUFSIZE];
380 if (nr_cpus_avail > 0)
381 return nr_cpus_avail;
383 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
384 if (nr_cpus_avail <= 0) {
386 "WARNING:\tunable to get available CPUs in this system: %s\n"
387 " \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
390 return nr_cpus_avail;
393 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
395 char *obj_path = strdup(path);
400 pr_warning("WARNING: Not enough memory, skip object dumping\n");
404 p = strrchr(obj_path, '.');
405 if (!p || (strcmp(p, ".c") != 0)) {
406 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
412 fp = fopen(obj_path, "wb");
414 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
415 obj_path, strerror(errno));
419 pr_info("LLVM: dumping %s\n", obj_path);
420 if (fwrite(obj_buf, size, 1, fp) != 1)
421 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
422 obj_path, strerror(errno));
428 int llvm__compile_bpf(const char *path, void **p_obj_buf,
429 size_t *p_obj_buf_sz)
432 void *obj_buf = NULL;
433 int err, nr_cpus_avail;
434 unsigned int kernel_version;
435 char linux_version_code_str[64];
436 const char *clang_opt = llvm_param.clang_opt;
437 char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
438 char serr[STRERR_BUFSIZE];
439 char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
440 *perf_bpf_include_opts = NULL;
441 const char *template = llvm_param.clang_bpf_cmd_template;
442 char *pipe_template = NULL;
443 const char *opts = llvm_param.opts;
444 char *command_echo = NULL, *command_out;
445 char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
447 if (path[0] != '-' && realpath(path, abspath) == NULL) {
449 pr_err("ERROR: problems with path %s: %s\n",
450 path, str_error_r(err, serr, sizeof(serr)));
455 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
457 err = search_program(llvm_param.clang_path,
458 "clang", clang_path);
461 "ERROR:\tunable to find clang.\n"
462 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
463 " \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
469 * This is an optional work. Even it fail we can continue our
470 * work. Needn't to check error return.
472 llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
474 nr_cpus_avail = llvm__get_nr_cpus();
475 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
478 if (fetch_kernel_version(&kernel_version, NULL, 0))
481 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
482 "0x%x", kernel_version);
483 if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
485 force_set_env("NR_CPUS", nr_cpus_avail_str);
486 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
487 force_set_env("CLANG_EXEC", clang_path);
488 force_set_env("CLANG_OPTIONS", clang_opt);
489 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
490 force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
491 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
494 err = search_program(llvm_param.llc_path, "llc", llc_path);
496 pr_err("ERROR:\tunable to find llc.\n"
497 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
498 " \tand 'llc-path' option in [llvm] section of ~/.perfconfig.\n");
503 if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
504 template, llc_path, opts) < 0) {
505 pr_err("ERROR:\tnot enough memory to setup command line\n");
509 template = pipe_template;
514 * Since we may reset clang's working dir, path of source file
515 * should be transferred into absolute path, except we want
516 * stdin to be source file (testing).
518 force_set_env("CLANG_SOURCE",
519 (path[0] == '-') ? path : abspath);
521 pr_debug("llvm compiling command template: %s\n", template);
523 if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
526 err = read_from_pipe(command_echo, (void **) &command_out, NULL);
530 pr_debug("llvm compiling command : %s\n", command_out);
532 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
534 pr_err("ERROR:\tunable to compile %s\n", path);
535 pr_err("Hint:\tCheck error message shown above.\n");
536 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
537 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
538 pr_err(" \twith proper -I and -D options.\n");
545 free(kbuild_include_opts);
546 free(perf_bpf_include_opts);
547 free(perf_include_dir);
552 *p_obj_buf = obj_buf;
555 *p_obj_buf_sz = obj_buf_sz;
560 free(kbuild_include_opts);
562 free(perf_bpf_include_opts);
563 free(perf_include_dir);
572 int llvm__search_clang(void)
574 char clang_path[PATH_MAX];
576 return search_program(llvm_param.clang_path, "clang", clang_path);