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 $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
  26
  27 struct llvm_param llvm_param = {
  28         .clang_path = "clang",
  29         .llc_path = "llc",
  30         .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
  31         .clang_opt = NULL,
  32         .opts = NULL,
  33         .kbuild_dir = NULL,
  34         .kbuild_opts = NULL,
  35         .user_set_param = false,
  36 };
  37
  38 int perf_llvm_config(const char *var, const char *value)
  39 {
  40         if (!strstarts(var, "llvm."))
  41                 return 0;
  42         var += sizeof("llvm.") - 1;
  43
  44         if (!strcmp(var, "clang-path"))
  45                 llvm_param.clang_path = strdup(value);
  46         else if (!strcmp(var, "clang-bpf-cmd-template"))
  47                 llvm_param.clang_bpf_cmd_template = strdup(value);
  48         else if (!strcmp(var, "clang-opt"))
  49                 llvm_param.clang_opt = strdup(value);
  50         else if (!strcmp(var, "kbuild-dir"))
  51                 llvm_param.kbuild_dir = strdup(value);
  52         else if (!strcmp(var, "kbuild-opts"))
  53                 llvm_param.kbuild_opts = strdup(value);
  54         else if (!strcmp(var, "dump-obj"))
  55                 llvm_param.dump_obj = !!perf_config_bool(var, value);
  56         else if (!strcmp(var, "opts"))
  57                 llvm_param.opts = strdup(value);
  58         else {
  59                 pr_debug("Invalid LLVM config option: %s\n", value);
  60                 return -1;
  61         }
  62         llvm_param.user_set_param = true;
  63         return 0;
  64 }
  65
  66 static int
  67 search_program(const char *def, const char *name,
  68                char *output)
  69 {
  70         char *env, *path, *tmp = NULL;
  71         char buf[PATH_MAX];
  72         int ret;
  73
  74         output[0] = '\0';
  75         if (def && def[0] != '\0') {
  76                 if (def[0] == '/') {
  77                         if (access(def, F_OK) == 0) {
  78                                 strlcpy(output, def, PATH_MAX);
  79                                 return 0;
  80                         }
  81                 } else if (def[0] != '\0')
  82                         name = def;
  83         }
  84
  85         env = getenv("PATH");
  86         if (!env)
  87                 return -1;
  88         env = strdup(env);
  89         if (!env)
  90                 return -1;
  91
  92         ret = -ENOENT;
  93         path = strtok_r(env, ":",  &tmp);
  94         while (path) {
  95                 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
  96                 if (access(buf, F_OK) == 0) {
  97                         strlcpy(output, buf, PATH_MAX);
  98                         ret = 0;
  99                         break;
 100                 }
 101                 path = strtok_r(NULL, ":", &tmp);
 102         }
 103
 104         free(env);
 105         return ret;
 106 }
 107
 108 #define READ_SIZE       4096
 109 static int
 110 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
 111 {
 112         int err = 0;
 113         void *buf = NULL;
 114         FILE *file = NULL;
 115         size_t read_sz = 0, buf_sz = 0;
 116         char serr[STRERR_BUFSIZE];
 117
 118         file = popen(cmd, "r");
 119         if (!file) {
 120                 pr_err("ERROR: unable to popen cmd: %s\n",
 121                        str_error_r(errno, serr, sizeof(serr)));
 122                 return -EINVAL;
 123         }
 124
 125         while (!feof(file) && !ferror(file)) {
 126                 /*
 127                  * Make buf_sz always have obe byte extra space so we
 128                  * can put '\0' there.
 129                  */
 130                 if (buf_sz - read_sz < READ_SIZE + 1) {
 131                         void *new_buf;
 132
 133                         buf_sz = read_sz + READ_SIZE + 1;
 134                         new_buf = realloc(buf, buf_sz);
 135
 136                         if (!new_buf) {
 137                                 pr_err("ERROR: failed to realloc memory\n");
 138                                 err = -ENOMEM;
 139                                 goto errout;
 140                         }
 141
 142                         buf = new_buf;
 143                 }
 144                 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
 145         }
 146
 147         if (buf_sz - read_sz < 1) {
 148                 pr_err("ERROR: internal error\n");
 149                 err = -EINVAL;
 150                 goto errout;
 151         }
 152
 153         if (ferror(file)) {
 154                 pr_err("ERROR: error occurred when reading from pipe: %s\n",
 155                        str_error_r(errno, serr, sizeof(serr)));
 156                 err = -EIO;
 157                 goto errout;
 158         }
 159
 160         err = WEXITSTATUS(pclose(file));
 161         file = NULL;
 162         if (err) {
 163                 err = -EINVAL;
 164                 goto errout;
 165         }
 166
 167         /*
 168          * If buf is string, give it terminal '\0' to make our life
 169          * easier. If buf is not string, that '\0' is out of space
 170          * indicated by read_sz so caller won't even notice it.
 171          */
 172         ((char *)buf)[read_sz] = '\0';
 173
 174         if (!p_buf)
 175                 free(buf);
 176         else
 177                 *p_buf = buf;
 178
 179         if (p_read_sz)
 180                 *p_read_sz = read_sz;
 181         return 0;
 182
 183 errout:
 184         if (file)
 185                 pclose(file);
 186         free(buf);
 187         if (p_buf)
 188                 *p_buf = NULL;
 189         if (p_read_sz)
 190                 *p_read_sz = 0;
 191         return err;
 192 }
 193
 194 static inline void
 195 force_set_env(const char *var, const char *value)
 196 {
 197         if (value) {
 198                 setenv(var, value, 1);
 199                 pr_debug("set env: %s=%s\n", var, value);
 200         } else {
 201                 unsetenv(var);
 202                 pr_debug("unset env: %s\n", var);
 203         }
 204 }
 205
 206 static void
 207 version_notice(void)
 208 {
 209         pr_err(
 210 "     \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
 211 "     \tYou may want to try git trunk:\n"
 212 "     \t\tgit clone http://llvm.org/git/llvm.git\n"
 213 "     \t\t     and\n"
 214 "     \t\tgit clone http://llvm.org/git/clang.git\n\n"
 215 "     \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
 216 "     \tdebian/ubuntu:\n"
 217 "     \t\thttp://llvm.org/apt\n\n"
 218 "     \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
 219 "     \toption in [llvm] section of ~/.perfconfig to:\n\n"
 220 "     \t  \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
 221 "     \t     -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
 222 "     \t     -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
 223 "     \t(Replace /path/to/llc with path to your llc)\n\n"
 224 );
 225 }
 226
 227 static int detect_kbuild_dir(char **kbuild_dir)
 228 {
 229         const char *test_dir = llvm_param.kbuild_dir;
 230         const char *prefix_dir = "";
 231         const char *suffix_dir = "";
 232
 233         /* _UTSNAME_LENGTH is 65 */
 234         char release[128];
 235
 236         char *autoconf_path;
 237
 238         int err;
 239
 240         if (!test_dir) {
 241                 err = fetch_kernel_version(NULL, release,
 242                                            sizeof(release));
 243                 if (err)
 244                         return -EINVAL;
 245
 246                 test_dir = release;
 247                 prefix_dir = "/lib/modules/";
 248                 suffix_dir = "/build";
 249         }
 250
 251         err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
 252                        prefix_dir, test_dir, suffix_dir);
 253         if (err < 0)
 254                 return -ENOMEM;
 255
 256         if (access(autoconf_path, R_OK) == 0) {
 257                 free(autoconf_path);
 258
 259                 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
 260                                suffix_dir);
 261                 if (err < 0)
 262                         return -ENOMEM;
 263                 return 0;
 264         }
 265         free(autoconf_path);
 266         return -ENOENT;
 267 }
 268
 269 static const char *kinc_fetch_script =
 270 "#!/usr/bin/env sh\n"
 271 "if ! test -d \"$KBUILD_DIR\"\n"
 272 "then\n"
 273 "       exit 1\n"
 274 "fi\n"
 275 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
 276 "then\n"
 277 "       exit 1\n"
 278 "fi\n"
 279 "TMPDIR=`mktemp -d`\n"
 280 "if test -z \"$TMPDIR\"\n"
 281 "then\n"
 282 "    exit 1\n"
 283 "fi\n"
 284 "cat << EOF > $TMPDIR/Makefile\n"
 285 "obj-y := dummy.o\n"
 286 "\\$(obj)/%.o: \\$(src)/%.c\n"
 287 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
 288 "EOF\n"
 289 "touch $TMPDIR/dummy.c\n"
 290 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
 291 "RET=$?\n"
 292 "rm -rf $TMPDIR\n"
 293 "exit $RET\n";
 294
 295 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
 296 {
 297         static char *saved_kbuild_dir;
 298         static char *saved_kbuild_include_opts;
 299         int err;
 300
 301         if (!kbuild_dir || !kbuild_include_opts)
 302                 return;
 303
 304         *kbuild_dir = NULL;
 305         *kbuild_include_opts = NULL;
 306
 307         if (saved_kbuild_dir && saved_kbuild_include_opts &&
 308             !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
 309                 *kbuild_dir = strdup(saved_kbuild_dir);
 310                 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
 311
 312                 if (*kbuild_dir && *kbuild_include_opts)
 313                         return;
 314
 315                 zfree(kbuild_dir);
 316                 zfree(kbuild_include_opts);
 317                 /*
 318                  * Don't fall through: it may breaks saved_kbuild_dir and
 319                  * saved_kbuild_include_opts if detect them again when
 320                  * memory is low.
 321                  */
 322                 return;
 323         }
 324
 325         if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
 326                 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
 327                 pr_debug("Skip kbuild options detection.\n");
 328                 goto errout;
 329         }
 330
 331         err = detect_kbuild_dir(kbuild_dir);
 332         if (err) {
 333                 pr_warning(
 334 "WARNING:\tunable to get correct kernel building directory.\n"
 335 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
 336 "     \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
 337 "     \tdetection.\n\n");
 338                 goto errout;
 339         }
 340
 341         pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
 342         force_set_env("KBUILD_DIR", *kbuild_dir);
 343         force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
 344         err = read_from_pipe(kinc_fetch_script,
 345                              (void **)kbuild_include_opts,
 346                              NULL);
 347         if (err) {
 348                 pr_warning(
 349 "WARNING:\tunable to get kernel include directories from '%s'\n"
 350 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
 351 "     \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
 352 "     \toption in [llvm] to \"\" to suppress this detection.\n\n",
 353                         *kbuild_dir);
 354
 355                 free(*kbuild_dir);
 356                 *kbuild_dir = NULL;
 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                 err = -ENOMEM;
 504                 if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
 505                               template, llc_path, opts) < 0) {
 506                         pr_err("ERROR:\tnot enough memory to setup command line\n");
 507                         goto errout;
 508                 }
 509
 510                 template = pipe_template;
 511
 512         }
 513
 514         /*
 515          * Since we may reset clang's working dir, path of source file
 516          * should be transferred into absolute path, except we want
 517          * stdin to be source file (testing).
 518          */
 519         force_set_env("CLANG_SOURCE",
 520                       (path[0] == '-') ? path : abspath);
 521
 522         pr_debug("llvm compiling command template: %s\n", template);
 523
 524         /*
 525          * Below, substitute control characters for values that can cause the
 526          * echo to misbehave, then substitute the values back.
 527          */
 528         err = -ENOMEM;
 529         if (asprintf(&command_echo, "echo -n \a%s\a", template) < 0)
 530                 goto errout;
 531
 532 #define SWAP_CHAR(a, b) do { if (*p == a) *p = b; } while (0)
 533         for (char *p = command_echo; *p; p++) {
 534                 SWAP_CHAR('<', '\001');
 535                 SWAP_CHAR('>', '\002');
 536                 SWAP_CHAR('"', '\003');
 537                 SWAP_CHAR('\'', '\004');
 538                 SWAP_CHAR('|', '\005');
 539                 SWAP_CHAR('&', '\006');
 540                 SWAP_CHAR('\a', '"');
 541         }
 542         err = read_from_pipe(command_echo, (void **) &command_out, NULL);
 543         if (err)
 544                 goto errout;
 545
 546         for (char *p = command_out; *p; p++) {
 547                 SWAP_CHAR('\001', '<');
 548                 SWAP_CHAR('\002', '>');
 549                 SWAP_CHAR('\003', '"');
 550                 SWAP_CHAR('\004', '\'');
 551                 SWAP_CHAR('\005', '|');
 552                 SWAP_CHAR('\006', '&');
 553         }
 554 #undef SWAP_CHAR
 555         pr_debug("llvm compiling command : %s\n", command_out);
 556
 557         err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
 558         if (err) {
 559                 pr_err("ERROR:\tunable to compile %s\n", path);
 560                 pr_err("Hint:\tCheck error message shown above.\n");
 561                 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
 562                 pr_err("     \t\tclang -target bpf -O2 -c %s\n", path);
 563                 pr_err("     \twith proper -I and -D options.\n");
 564                 goto errout;
 565         }
 566
 567         free(command_echo);
 568         free(command_out);
 569         free(kbuild_dir);
 570         free(kbuild_include_opts);
 571         free(perf_bpf_include_opts);
 572         free(perf_include_dir);
 573
 574         if (!p_obj_buf)
 575                 free(obj_buf);
 576         else
 577                 *p_obj_buf = obj_buf;
 578
 579         if (p_obj_buf_sz)
 580                 *p_obj_buf_sz = obj_buf_sz;
 581         return 0;
 582 errout:
 583         free(command_echo);
 584         free(kbuild_dir);
 585         free(kbuild_include_opts);
 586         free(obj_buf);
 587         free(perf_bpf_include_opts);
 588         free(perf_include_dir);
 589         free(pipe_template);
 590         if (p_obj_buf)
 591                 *p_obj_buf = NULL;
 592         if (p_obj_buf_sz)
 593                 *p_obj_buf_sz = 0;
 594         return err;
 595 }
 596
 597 int llvm__search_clang(void)
 598 {
 599         char clang_path[PATH_MAX];
 600
 601         return search_program(llvm_param.clang_path, "clang", clang_path);
 602 }