tools/perf/util/llvm-utils.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
   4  * Copyright (C) 2015, Huawei Inc.
   5  */
   6
   7 #include <errno.h>
   8 #include <limits.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <linux/err.h>
  12 #include "debug.h"
  13 #include "llvm-utils.h"
  14 #include "config.h"
  15 #include "util.h"
  16 #include <sys/wait.h>
  17 #include <subcmd/exec-cmd.h>
  18
  19 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE                          \
  20                 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
  21                 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE "     \
  22                 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS " \
  23                 "-Wno-unused-value -Wno-pointer-sign "          \
  24                 "-working-directory $WORKING_DIR "              \
  25                 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
  26
  27 struct llvm_param llvm_param = {
  28         .clang_path = "clang",
  29         .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
  30         .clang_opt = NULL,
  31         .kbuild_dir = NULL,
  32         .kbuild_opts = NULL,
  33         .user_set_param = false,
  34 };
  35
  36 int perf_llvm_config(const char *var, const char *value)
  37 {
  38         if (!strstarts(var, "llvm."))
  39                 return 0;
  40         var += sizeof("llvm.") - 1;
  41
  42         if (!strcmp(var, "clang-path"))
  43                 llvm_param.clang_path = strdup(value);
  44         else if (!strcmp(var, "clang-bpf-cmd-template"))
  45                 llvm_param.clang_bpf_cmd_template = strdup(value);
  46         else if (!strcmp(var, "clang-opt"))
  47                 llvm_param.clang_opt = strdup(value);
  48         else if (!strcmp(var, "kbuild-dir"))
  49                 llvm_param.kbuild_dir = strdup(value);
  50         else if (!strcmp(var, "kbuild-opts"))
  51                 llvm_param.kbuild_opts = strdup(value);
  52         else if (!strcmp(var, "dump-obj"))
  53                 llvm_param.dump_obj = !!perf_config_bool(var, value);
  54         else {
  55                 pr_debug("Invalid LLVM config option: %s\n", value);
  56                 return -1;
  57         }
  58         llvm_param.user_set_param = true;
  59         return 0;
  60 }
  61
  62 static int
  63 search_program(const char *def, const char *name,
  64                char *output)
  65 {
  66         char *env, *path, *tmp = NULL;
  67         char buf[PATH_MAX];
  68         int ret;
  69
  70         output[0] = '\0';
  71         if (def && def[0] != '\0') {
  72                 if (def[0] == '/') {
  73                         if (access(def, F_OK) == 0) {
  74                                 strlcpy(output, def, PATH_MAX);
  75                                 return 0;
  76                         }
  77                 } else if (def[0] != '\0')
  78                         name = def;
  79         }
  80
  81         env = getenv("PATH");
  82         if (!env)
  83                 return -1;
  84         env = strdup(env);
  85         if (!env)
  86                 return -1;
  87
  88         ret = -ENOENT;
  89         path = strtok_r(env, ":",  &tmp);
  90         while (path) {
  91                 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
  92                 if (access(buf, F_OK) == 0) {
  93                         strlcpy(output, buf, PATH_MAX);
  94                         ret = 0;
  95                         break;
  96                 }
  97                 path = strtok_r(NULL, ":", &tmp);
  98         }
  99
 100         free(env);
 101         return ret;
 102 }
 103
 104 #define READ_SIZE       4096
 105 static int
 106 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
 107 {
 108         int err = 0;
 109         void *buf = NULL;
 110         FILE *file = NULL;
 111         size_t read_sz = 0, buf_sz = 0;
 112         char serr[STRERR_BUFSIZE];
 113
 114         file = popen(cmd, "r");
 115         if (!file) {
 116                 pr_err("ERROR: unable to popen cmd: %s\n",
 117                        str_error_r(errno, serr, sizeof(serr)));
 118                 return -EINVAL;
 119         }
 120
 121         while (!feof(file) && !ferror(file)) {
 122                 /*
 123                  * Make buf_sz always have obe byte extra space so we
 124                  * can put '\0' there.
 125                  */
 126                 if (buf_sz - read_sz < READ_SIZE + 1) {
 127                         void *new_buf;
 128
 129                         buf_sz = read_sz + READ_SIZE + 1;
 130                         new_buf = realloc(buf, buf_sz);
 131
 132                         if (!new_buf) {
 133                                 pr_err("ERROR: failed to realloc memory\n");
 134                                 err = -ENOMEM;
 135                                 goto errout;
 136                         }
 137
 138                         buf = new_buf;
 139                 }
 140                 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
 141         }
 142
 143         if (buf_sz - read_sz < 1) {
 144                 pr_err("ERROR: internal error\n");
 145                 err = -EINVAL;
 146                 goto errout;
 147         }
 148
 149         if (ferror(file)) {
 150                 pr_err("ERROR: error occurred when reading from pipe: %s\n",
 151                        str_error_r(errno, serr, sizeof(serr)));
 152                 err = -EIO;
 153                 goto errout;
 154         }
 155
 156         err = WEXITSTATUS(pclose(file));
 157         file = NULL;
 158         if (err) {
 159                 err = -EINVAL;
 160                 goto errout;
 161         }
 162
 163         /*
 164          * If buf is string, give it terminal '\0' to make our life
 165          * easier. If buf is not string, that '\0' is out of space
 166          * indicated by read_sz so caller won't even notice it.
 167          */
 168         ((char *)buf)[read_sz] = '\0';
 169
 170         if (!p_buf)
 171                 free(buf);
 172         else
 173                 *p_buf = buf;
 174
 175         if (p_read_sz)
 176                 *p_read_sz = read_sz;
 177         return 0;
 178
 179 errout:
 180         if (file)
 181                 pclose(file);
 182         free(buf);
 183         if (p_buf)
 184                 *p_buf = NULL;
 185         if (p_read_sz)
 186                 *p_read_sz = 0;
 187         return err;
 188 }
 189
 190 static inline void
 191 force_set_env(const char *var, const char *value)
 192 {
 193         if (value) {
 194                 setenv(var, value, 1);
 195                 pr_debug("set env: %s=%s\n", var, value);
 196         } else {
 197                 unsetenv(var);
 198                 pr_debug("unset env: %s\n", var);
 199         }
 200 }
 201
 202 static void
 203 version_notice(void)
 204 {
 205         pr_err(
 206 "     \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
 207 "     \tYou may want to try git trunk:\n"
 208 "     \t\tgit clone http://llvm.org/git/llvm.git\n"
 209 "     \t\t     and\n"
 210 "     \t\tgit clone http://llvm.org/git/clang.git\n\n"
 211 "     \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
 212 "     \tdebian/ubuntu:\n"
 213 "     \t\thttp://llvm.org/apt\n\n"
 214 "     \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
 215 "     \toption in [llvm] section of ~/.perfconfig to:\n\n"
 216 "     \t  \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
 217 "     \t     -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
 218 "     \t     -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
 219 "     \t(Replace /path/to/llc with path to your llc)\n\n"
 220 );
 221 }
 222
 223 static int detect_kbuild_dir(char **kbuild_dir)
 224 {
 225         const char *test_dir = llvm_param.kbuild_dir;
 226         const char *prefix_dir = "";
 227         const char *suffix_dir = "";
 228
 229         char *autoconf_path;
 230
 231         int err;
 232
 233         if (!test_dir) {
 234                 /* _UTSNAME_LENGTH is 65 */
 235                 char release[128];
 236
 237                 err = fetch_kernel_version(NULL, release,
 238                                            sizeof(release));
 239                 if (err)
 240                         return -EINVAL;
 241
 242                 test_dir = release;
 243                 prefix_dir = "/lib/modules/";
 244                 suffix_dir = "/build";
 245         }
 246
 247         err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
 248                        prefix_dir, test_dir, suffix_dir);
 249         if (err < 0)
 250                 return -ENOMEM;
 251
 252         if (access(autoconf_path, R_OK) == 0) {
 253                 free(autoconf_path);
 254
 255                 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
 256                                suffix_dir);
 257                 if (err < 0)
 258                         return -ENOMEM;
 259                 return 0;
 260         }
 261         free(autoconf_path);
 262         return -ENOENT;
 263 }
 264
 265 static const char *kinc_fetch_script =
 266 "#!/usr/bin/env sh\n"
 267 "if ! test -d \"$KBUILD_DIR\"\n"
 268 "then\n"
 269 "       exit 1\n"
 270 "fi\n"
 271 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
 272 "then\n"
 273 "       exit 1\n"
 274 "fi\n"
 275 "TMPDIR=`mktemp -d`\n"
 276 "if test -z \"$TMPDIR\"\n"
 277 "then\n"
 278 "    exit 1\n"
 279 "fi\n"
 280 "cat << EOF > $TMPDIR/Makefile\n"
 281 "obj-y := dummy.o\n"
 282 "\\$(obj)/%.o: \\$(src)/%.c\n"
 283 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
 284 "EOF\n"
 285 "touch $TMPDIR/dummy.c\n"
 286 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
 287 "RET=$?\n"
 288 "rm -rf $TMPDIR\n"
 289 "exit $RET\n";
 290
 291 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
 292 {
 293         static char *saved_kbuild_dir;
 294         static char *saved_kbuild_include_opts;
 295         int err;
 296
 297         if (!kbuild_dir || !kbuild_include_opts)
 298                 return;
 299
 300         *kbuild_dir = NULL;
 301         *kbuild_include_opts = NULL;
 302
 303         if (saved_kbuild_dir && saved_kbuild_include_opts &&
 304             !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
 305                 *kbuild_dir = strdup(saved_kbuild_dir);
 306                 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
 307
 308                 if (*kbuild_dir && *kbuild_include_opts)
 309                         return;
 310
 311                 zfree(kbuild_dir);
 312                 zfree(kbuild_include_opts);
 313                 /*
 314                  * Don't fall through: it may breaks saved_kbuild_dir and
 315                  * saved_kbuild_include_opts if detect them again when
 316                  * memory is low.
 317                  */
 318                 return;
 319         }
 320
 321         if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
 322                 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
 323                 pr_debug("Skip kbuild options detection.\n");
 324                 goto errout;
 325         }
 326
 327         err = detect_kbuild_dir(kbuild_dir);
 328         if (err) {
 329                 pr_warning(
 330 "WARNING:\tunable to get correct kernel building directory.\n"
 331 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
 332 "     \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
 333 "     \tdetection.\n\n");
 334                 goto errout;
 335         }
 336
 337         pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
 338         force_set_env("KBUILD_DIR", *kbuild_dir);
 339         force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
 340         err = read_from_pipe(kinc_fetch_script,
 341                              (void **)kbuild_include_opts,
 342                              NULL);
 343         if (err) {
 344                 pr_warning(
 345 "WARNING:\tunable to get kernel include directories from '%s'\n"
 346 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
 347 "     \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
 348 "     \toption in [llvm] to \"\" to suppress this detection.\n\n",
 349                         *kbuild_dir);
 350
 351                 free(*kbuild_dir);
 352                 *kbuild_dir = NULL;
 353                 goto errout;
 354         }
 355
 356         pr_debug("include option is set to %s\n", *kbuild_include_opts);
 357
 358         saved_kbuild_dir = strdup(*kbuild_dir);
 359         saved_kbuild_include_opts = strdup(*kbuild_include_opts);
 360
 361         if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
 362                 zfree(&saved_kbuild_dir);
 363                 zfree(&saved_kbuild_include_opts);
 364         }
 365         return;
 366 errout:
 367         saved_kbuild_dir = ERR_PTR(-EINVAL);
 368         saved_kbuild_include_opts = ERR_PTR(-EINVAL);
 369 }
 370
 371 int llvm__get_nr_cpus(void)
 372 {
 373         static int nr_cpus_avail = 0;
 374         char serr[STRERR_BUFSIZE];
 375
 376         if (nr_cpus_avail > 0)
 377                 return nr_cpus_avail;
 378
 379         nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
 380         if (nr_cpus_avail <= 0) {
 381                 pr_err(
 382 "WARNING:\tunable to get available CPUs in this system: %s\n"
 383 "        \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
 384                 nr_cpus_avail = 128;
 385         }
 386         return nr_cpus_avail;
 387 }
 388
 389 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
 390 {
 391         char *obj_path = strdup(path);
 392         FILE *fp;
 393         char *p;
 394
 395         if (!obj_path) {
 396                 pr_warning("WARNING: Not enough memory, skip object dumping\n");
 397                 return;
 398         }
 399
 400         p = strrchr(obj_path, '.');
 401         if (!p || (strcmp(p, ".c") != 0)) {
 402                 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
 403                            obj_path);
 404                 goto out;
 405         }
 406
 407         p[1] = 'o';
 408         fp = fopen(obj_path, "wb");
 409         if (!fp) {
 410                 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
 411                            obj_path, strerror(errno));
 412                 goto out;
 413         }
 414
 415         pr_info("LLVM: dumping %s\n", obj_path);
 416         if (fwrite(obj_buf, size, 1, fp) != 1)
 417                 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
 418                            obj_path, strerror(errno));
 419         fclose(fp);
 420 out:
 421         free(obj_path);
 422 }
 423
 424 int llvm__compile_bpf(const char *path, void **p_obj_buf,
 425                       size_t *p_obj_buf_sz)
 426 {
 427         size_t obj_buf_sz;
 428         void *obj_buf = NULL;
 429         int err, nr_cpus_avail;
 430         unsigned int kernel_version;
 431         char linux_version_code_str[64];
 432         const char *clang_opt = llvm_param.clang_opt;
 433         char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
 434         char serr[STRERR_BUFSIZE];
 435         char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
 436              *perf_bpf_include_opts = NULL;
 437         const char *template = llvm_param.clang_bpf_cmd_template;
 438         char *command_echo = NULL, *command_out;
 439         char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
 440
 441         if (path[0] != '-' && realpath(path, abspath) == NULL) {
 442                 err = errno;
 443                 pr_err("ERROR: problems with path %s: %s\n",
 444                        path, str_error_r(err, serr, sizeof(serr)));
 445                 return -err;
 446         }
 447
 448         if (!template)
 449                 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
 450
 451         err = search_program(llvm_param.clang_path,
 452                              "clang", clang_path);
 453         if (err) {
 454                 pr_err(
 455 "ERROR:\tunable to find clang.\n"
 456 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
 457 "     \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
 458                 version_notice();
 459                 return -ENOENT;
 460         }
 461
 462         /*
 463          * This is an optional work. Even it fail we can continue our
 464          * work. Needn't to check error return.
 465          */
 466         llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
 467
 468         nr_cpus_avail = llvm__get_nr_cpus();
 469         snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
 470                  nr_cpus_avail);
 471
 472         if (fetch_kernel_version(&kernel_version, NULL, 0))
 473                 kernel_version = 0;
 474
 475         snprintf(linux_version_code_str, sizeof(linux_version_code_str),
 476                  "0x%x", kernel_version);
 477         if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
 478                 goto errout;
 479         force_set_env("NR_CPUS", nr_cpus_avail_str);
 480         force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
 481         force_set_env("CLANG_EXEC", clang_path);
 482         force_set_env("CLANG_OPTIONS", clang_opt);
 483         force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
 484         force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
 485         force_set_env("WORKING_DIR", kbuild_dir ? : ".");
 486
 487         /*
 488          * Since we may reset clang's working dir, path of source file
 489          * should be transferred into absolute path, except we want
 490          * stdin to be source file (testing).
 491          */
 492         force_set_env("CLANG_SOURCE",
 493                       (path[0] == '-') ? path : abspath);
 494
 495         pr_debug("llvm compiling command template: %s\n", template);
 496
 497         if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
 498                 goto errout;
 499
 500         err = read_from_pipe(command_echo, (void **) &command_out, NULL);
 501         if (err)
 502                 goto errout;
 503
 504         pr_debug("llvm compiling command : %s\n", command_out);
 505
 506         err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
 507         if (err) {
 508                 pr_err("ERROR:\tunable to compile %s\n", path);
 509                 pr_err("Hint:\tCheck error message shown above.\n");
 510                 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
 511                 pr_err("     \t\tclang -target bpf -O2 -c %s\n", path);
 512                 pr_err("     \twith proper -I and -D options.\n");
 513                 goto errout;
 514         }
 515
 516         free(command_echo);
 517         free(command_out);
 518         free(kbuild_dir);
 519         free(kbuild_include_opts);
 520         free(perf_bpf_include_opts);
 521         free(perf_include_dir);
 522
 523         if (!p_obj_buf)
 524                 free(obj_buf);
 525         else
 526                 *p_obj_buf = obj_buf;
 527
 528         if (p_obj_buf_sz)
 529                 *p_obj_buf_sz = obj_buf_sz;
 530         return 0;
 531 errout:
 532         free(command_echo);
 533         free(kbuild_dir);
 534         free(kbuild_include_opts);
 535         free(obj_buf);
 536         free(perf_bpf_include_opts);
 537         free(perf_include_dir);
 538         if (p_obj_buf)
 539                 *p_obj_buf = NULL;
 540         if (p_obj_buf_sz)
 541                 *p_obj_buf_sz = 0;
 542         return err;
 543 }
 544
 545 int llvm__search_clang(void)
 546 {
 547         char clang_path[PATH_MAX];
 548
 549         return search_program(llvm_param.clang_path, "clang", clang_path);
 550 }