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 <linux/zalloc.h>
  13 #include "debug.h"
  14 #include "llvm-utils.h"
  15 #include "config.h"
  16 #include "util.h"
  17 #include <sys/wait.h>
  18 #include <subcmd/exec-cmd.h>
  19
  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"
  27
  28 struct llvm_param llvm_param = {
  29         .clang_path = "clang",
  30         .llc_path = "llc",
  31         .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
  32         .clang_opt = NULL,
  33         .opts = NULL,
  34         .kbuild_dir = NULL,
  35         .kbuild_opts = NULL,
  36         .user_set_param = false,
  37 };
  38
  39 int perf_llvm_config(const char *var, const char *value)
  40 {
  41         if (!strstarts(var, "llvm."))
  42                 return 0;
  43         var += sizeof("llvm.") - 1;
  44
  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);
  59         else {
  60                 pr_debug("Invalid LLVM config option: %s\n", value);
  61                 return -1;
  62         }
  63         llvm_param.user_set_param = true;
  64         return 0;
  65 }
  66
  67 static int
  68 search_program(const char *def, const char *name,
  69                char *output)
  70 {
  71         char *env, *path, *tmp = NULL;
  72         char buf[PATH_MAX];
  73         int ret;
  74
  75         output[0] = '\0';
  76         if (def && def[0] != '\0') {
  77                 if (def[0] == '/') {
  78                         if (access(def, F_OK) == 0) {
  79                                 strlcpy(output, def, PATH_MAX);
  80                                 return 0;
  81                         }
  82                 } else if (def[0] != '\0')
  83                         name = def;
  84         }
  85
  86         env = getenv("PATH");
  87         if (!env)
  88                 return -1;
  89         env = strdup(env);
  90         if (!env)
  91                 return -1;
  92
  93         ret = -ENOENT;
  94         path = strtok_r(env, ":",  &tmp);
  95         while (path) {
  96                 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
  97                 if (access(buf, F_OK) == 0) {
  98                         strlcpy(output, buf, PATH_MAX);
  99                         ret = 0;
 100                         break;
 101                 }
 102                 path = strtok_r(NULL, ":", &tmp);
 103         }
 104
 105         free(env);
 106         return ret;
 107 }
 108
 109 #define READ_SIZE       4096
 110 static int
 111 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
 112 {
 113         int err = 0;
 114         void *buf = NULL;
 115         FILE *file = NULL;
 116         size_t read_sz = 0, buf_sz = 0;
 117         char serr[STRERR_BUFSIZE];
 118
 119         file = popen(cmd, "r");
 120         if (!file) {
 121                 pr_err("ERROR: unable to popen cmd: %s\n",
 122                        str_error_r(errno, serr, sizeof(serr)));
 123                 return -EINVAL;
 124         }
 125
 126         while (!feof(file) && !ferror(file)) {
 127                 /*
 128                  * Make buf_sz always have obe byte extra space so we
 129                  * can put '\0' there.
 130                  */
 131                 if (buf_sz - read_sz < READ_SIZE + 1) {
 132                         void *new_buf;
 133
 134                         buf_sz = read_sz + READ_SIZE + 1;
 135                         new_buf = realloc(buf, buf_sz);
 136
 137                         if (!new_buf) {
 138                                 pr_err("ERROR: failed to realloc memory\n");
 139                                 err = -ENOMEM;
 140                                 goto errout;
 141                         }
 142
 143                         buf = new_buf;
 144                 }
 145                 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
 146         }
 147
 148         if (buf_sz - read_sz < 1) {
 149                 pr_err("ERROR: internal error\n");
 150                 err = -EINVAL;
 151                 goto errout;
 152         }
 153
 154         if (ferror(file)) {
 155                 pr_err("ERROR: error occurred when reading from pipe: %s\n",
 156                        str_error_r(errno, serr, sizeof(serr)));
 157                 err = -EIO;
 158                 goto errout;
 159         }
 160
 161         err = WEXITSTATUS(pclose(file));
 162         file = NULL;
 163         if (err) {
 164                 err = -EINVAL;
 165                 goto errout;
 166         }
 167
 168         /*
 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.
 172          */
 173         ((char *)buf)[read_sz] = '\0';
 174
 175         if (!p_buf)
 176                 free(buf);
 177         else
 178                 *p_buf = buf;
 179
 180         if (p_read_sz)
 181                 *p_read_sz = read_sz;
 182         return 0;
 183
 184 errout:
 185         if (file)
 186                 pclose(file);
 187         free(buf);
 188         if (p_buf)
 189                 *p_buf = NULL;
 190         if (p_read_sz)
 191                 *p_read_sz = 0;
 192         return err;
 193 }
 194
 195 static inline void
 196 force_set_env(const char *var, const char *value)
 197 {
 198         if (value) {
 199                 setenv(var, value, 1);
 200                 pr_debug("set env: %s=%s\n", var, value);
 201         } else {
 202                 unsetenv(var);
 203                 pr_debug("unset env: %s\n", var);
 204         }
 205 }
 206
 207 static void
 208 version_notice(void)
 209 {
 210         pr_err(
 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"
 214 "     \t\t     and\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 $CLANG_SOURCE \\\n"
 223 "     \t     -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
 224 "     \t(Replace /path/to/llc with path to your llc)\n\n"
 225 );
 226 }
 227
 228 static int detect_kbuild_dir(char **kbuild_dir)
 229 {
 230         const char *test_dir = llvm_param.kbuild_dir;
 231         const char *prefix_dir = "";
 232         const char *suffix_dir = "";
 233
 234         char *autoconf_path;
 235
 236         int err;
 237
 238         if (!test_dir) {
 239                 /* _UTSNAME_LENGTH is 65 */
 240                 char release[128];
 241
 242                 err = fetch_kernel_version(NULL, release,
 243                                            sizeof(release));
 244                 if (err)
 245                         return -EINVAL;
 246
 247                 test_dir = release;
 248                 prefix_dir = "/lib/modules/";
 249                 suffix_dir = "/build";
 250         }
 251
 252         err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
 253                        prefix_dir, test_dir, suffix_dir);
 254         if (err < 0)
 255                 return -ENOMEM;
 256
 257         if (access(autoconf_path, R_OK) == 0) {
 258                 free(autoconf_path);
 259
 260                 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
 261                                suffix_dir);
 262                 if (err < 0)
 263                         return -ENOMEM;
 264                 return 0;
 265         }
 266         free(autoconf_path);
 267         return -ENOENT;
 268 }
 269
 270 static const char *kinc_fetch_script =
 271 "#!/usr/bin/env sh\n"
 272 "if ! test -d \"$KBUILD_DIR\"\n"
 273 "then\n"
 274 "       exit 1\n"
 275 "fi\n"
 276 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
 277 "then\n"
 278 "       exit 1\n"
 279 "fi\n"
 280 "TMPDIR=`mktemp -d`\n"
 281 "if test -z \"$TMPDIR\"\n"
 282 "then\n"
 283 "    exit 1\n"
 284 "fi\n"
 285 "cat << EOF > $TMPDIR/Makefile\n"
 286 "obj-y := dummy.o\n"
 287 "\\$(obj)/%.o: \\$(src)/%.c\n"
 288 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
 289 "EOF\n"
 290 "touch $TMPDIR/dummy.c\n"
 291 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
 292 "RET=$?\n"
 293 "rm -rf $TMPDIR\n"
 294 "exit $RET\n";
 295
 296 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
 297 {
 298         static char *saved_kbuild_dir;
 299         static char *saved_kbuild_include_opts;
 300         int err;
 301
 302         if (!kbuild_dir || !kbuild_include_opts)
 303                 return;
 304
 305         *kbuild_dir = NULL;
 306         *kbuild_include_opts = NULL;
 307
 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);
 312
 313                 if (*kbuild_dir && *kbuild_include_opts)
 314                         return;
 315
 316                 zfree(kbuild_dir);
 317                 zfree(kbuild_include_opts);
 318                 /*
 319                  * Don't fall through: it may breaks saved_kbuild_dir and
 320                  * saved_kbuild_include_opts if detect them again when
 321                  * memory is low.
 322                  */
 323                 return;
 324         }
 325
 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");
 329                 goto errout;
 330         }
 331
 332         err = detect_kbuild_dir(kbuild_dir);
 333         if (err) {
 334                 pr_warning(
 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");
 339                 goto errout;
 340         }
 341
 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,
 347                              NULL);
 348         if (err) {
 349                 pr_warning(
 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",
 354                         *kbuild_dir);
 355
 356                 zfree(kbuild_dir);
 357                 goto errout;
 358         }
 359
 360         pr_debug("include option is set to %s\n", *kbuild_include_opts);
 361
 362         saved_kbuild_dir = strdup(*kbuild_dir);
 363         saved_kbuild_include_opts = strdup(*kbuild_include_opts);
 364
 365         if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
 366                 zfree(&saved_kbuild_dir);
 367                 zfree(&saved_kbuild_include_opts);
 368         }
 369         return;
 370 errout:
 371         saved_kbuild_dir = ERR_PTR(-EINVAL);
 372         saved_kbuild_include_opts = ERR_PTR(-EINVAL);
 373 }
 374
 375 int llvm__get_nr_cpus(void)
 376 {
 377         static int nr_cpus_avail = 0;
 378         char serr[STRERR_BUFSIZE];
 379
 380         if (nr_cpus_avail > 0)
 381                 return nr_cpus_avail;
 382
 383         nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
 384         if (nr_cpus_avail <= 0) {
 385                 pr_err(
 386 "WARNING:\tunable to get available CPUs in this system: %s\n"
 387 "        \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
 388                 nr_cpus_avail = 128;
 389         }
 390         return nr_cpus_avail;
 391 }
 392
 393 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
 394 {
 395         char *obj_path = strdup(path);
 396         FILE *fp;
 397         char *p;
 398
 399         if (!obj_path) {
 400                 pr_warning("WARNING: Not enough memory, skip object dumping\n");
 401                 return;
 402         }
 403
 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",
 407                            obj_path);
 408                 goto out;
 409         }
 410
 411         p[1] = 'o';
 412         fp = fopen(obj_path, "wb");
 413         if (!fp) {
 414                 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
 415                            obj_path, strerror(errno));
 416                 goto out;
 417         }
 418
 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));
 423         fclose(fp);
 424 out:
 425         free(obj_path);
 426 }
 427
 428 int llvm__compile_bpf(const char *path, void **p_obj_buf,
 429                       size_t *p_obj_buf_sz)
 430 {
 431         size_t 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);
 446
 447         if (path[0] != '-' && realpath(path, abspath) == NULL) {
 448                 err = errno;
 449                 pr_err("ERROR: problems with path %s: %s\n",
 450                        path, str_error_r(err, serr, sizeof(serr)));
 451                 return -err;
 452         }
 453
 454         if (!template)
 455                 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
 456
 457         err = search_program(llvm_param.clang_path,
 458                              "clang", clang_path);
 459         if (err) {
 460                 pr_err(
 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");
 464                 version_notice();
 465                 return -ENOENT;
 466         }
 467
 468         /*
 469          * This is an optional work. Even it fail we can continue our
 470          * work. Needn't to check error return.
 471          */
 472         llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
 473
 474         nr_cpus_avail = llvm__get_nr_cpus();
 475         snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
 476                  nr_cpus_avail);
 477
 478         if (fetch_kernel_version(&kernel_version, NULL, 0))
 479                 kernel_version = 0;
 480
 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)
 484                 goto errout;
 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 ? : ".");
 492
 493         if (opts) {
 494                 err = search_program(llvm_param.llc_path, "llc", llc_path);
 495                 if (err) {
 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");
 499                         version_notice();
 500                         goto errout;
 501                 }
 502
 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");
 506                         goto errout;
 507                 }
 508
 509                 template = pipe_template;
 510
 511         }
 512
 513         /*
 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).
 517          */
 518         force_set_env("CLANG_SOURCE",
 519                       (path[0] == '-') ? path : abspath);
 520
 521         pr_debug("llvm compiling command template: %s\n", template);
 522
 523         if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
 524                 goto errout;
 525
 526         err = read_from_pipe(command_echo, (void **) &command_out, NULL);
 527         if (err)
 528                 goto errout;
 529
 530         pr_debug("llvm compiling command : %s\n", command_out);
 531
 532         err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
 533         if (err) {
 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");
 539                 goto errout;
 540         }
 541
 542         free(command_echo);
 543         free(command_out);
 544         free(kbuild_dir);
 545         free(kbuild_include_opts);
 546         free(perf_bpf_include_opts);
 547         free(perf_include_dir);
 548
 549         if (!p_obj_buf)
 550                 free(obj_buf);
 551         else
 552                 *p_obj_buf = obj_buf;
 553
 554         if (p_obj_buf_sz)
 555                 *p_obj_buf_sz = obj_buf_sz;
 556         return 0;
 557 errout:
 558         free(command_echo);
 559         free(kbuild_dir);
 560         free(kbuild_include_opts);
 561         free(obj_buf);
 562         free(perf_bpf_include_opts);
 563         free(perf_include_dir);
 564         free(pipe_template);
 565         if (p_obj_buf)
 566                 *p_obj_buf = NULL;
 567         if (p_obj_buf_sz)
 568                 *p_obj_buf_sz = 0;
 569         return err;
 570 }
 571
 572 int llvm__search_clang(void)
 573 {
 574         char clang_path[PATH_MAX];
 575
 576         return search_program(llvm_param.clang_path, "clang", clang_path);
 577 }