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 <unistd.h>
  12 #include <linux/err.h>
  13 #include <linux/string.h>
  14 #include <linux/zalloc.h>
  15 #include "debug.h"
  16 #include "llvm-utils.h"
  17 #include "config.h"
  18 #include "util.h"
  19 #include <sys/wait.h>
  20 #include <subcmd/exec-cmd.h>
  21
  22 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE                          \
  23                 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
  24                 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE "     \
  25                 "$CLANG_OPTIONS $PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \
  26                 "-Wno-unused-value -Wno-pointer-sign "          \
  27                 "-working-directory $WORKING_DIR "              \
  28                 "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
  29
  30 struct llvm_param llvm_param = {
  31         .clang_path = "clang",
  32         .llc_path = "llc",
  33         .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
  34         .clang_opt = NULL,
  35         .opts = NULL,
  36         .kbuild_dir = NULL,
  37         .kbuild_opts = NULL,
  38         .user_set_param = false,
  39 };
  40
  41 static void version_notice(void);
  42
  43 int perf_llvm_config(const char *var, const char *value)
  44 {
  45         if (!strstarts(var, "llvm."))
  46                 return 0;
  47         var += sizeof("llvm.") - 1;
  48
  49         if (!strcmp(var, "clang-path"))
  50                 llvm_param.clang_path = strdup(value);
  51         else if (!strcmp(var, "clang-bpf-cmd-template"))
  52                 llvm_param.clang_bpf_cmd_template = strdup(value);
  53         else if (!strcmp(var, "clang-opt"))
  54                 llvm_param.clang_opt = strdup(value);
  55         else if (!strcmp(var, "kbuild-dir"))
  56                 llvm_param.kbuild_dir = strdup(value);
  57         else if (!strcmp(var, "kbuild-opts"))
  58                 llvm_param.kbuild_opts = strdup(value);
  59         else if (!strcmp(var, "dump-obj"))
  60                 llvm_param.dump_obj = !!perf_config_bool(var, value);
  61         else if (!strcmp(var, "opts"))
  62                 llvm_param.opts = strdup(value);
  63         else {
  64                 pr_debug("Invalid LLVM config option: %s\n", value);
  65                 return -1;
  66         }
  67         llvm_param.user_set_param = true;
  68         return 0;
  69 }
  70
  71 static int
  72 search_program(const char *def, const char *name,
  73                char *output)
  74 {
  75         char *env, *path, *tmp = NULL;
  76         char buf[PATH_MAX];
  77         int ret;
  78
  79         output[0] = '\0';
  80         if (def && def[0] != '\0') {
  81                 if (def[0] == '/') {
  82                         if (access(def, F_OK) == 0) {
  83                                 strlcpy(output, def, PATH_MAX);
  84                                 return 0;
  85                         }
  86                 } else if (def[0] != '\0')
  87                         name = def;
  88         }
  89
  90         env = getenv("PATH");
  91         if (!env)
  92                 return -1;
  93         env = strdup(env);
  94         if (!env)
  95                 return -1;
  96
  97         ret = -ENOENT;
  98         path = strtok_r(env, ":",  &tmp);
  99         while (path) {
 100                 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
 101                 if (access(buf, F_OK) == 0) {
 102                         strlcpy(output, buf, PATH_MAX);
 103                         ret = 0;
 104                         break;
 105                 }
 106                 path = strtok_r(NULL, ":", &tmp);
 107         }
 108
 109         free(env);
 110         return ret;
 111 }
 112
 113 static int search_program_and_warn(const char *def, const char *name,
 114                                    char *output)
 115 {
 116         int ret = search_program(def, name, output);
 117
 118         if (ret) {
 119                 pr_err("ERROR:\tunable to find %s.\n"
 120                        "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
 121                        "     \tand '%s-path' option in [llvm] section of ~/.perfconfig.\n",
 122                        name, name);
 123                 version_notice();
 124         }
 125         return ret;
 126 }
 127
 128 #define READ_SIZE       4096
 129 static int
 130 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
 131 {
 132         int err = 0;
 133         void *buf = NULL;
 134         FILE *file = NULL;
 135         size_t read_sz = 0, buf_sz = 0;
 136         char serr[STRERR_BUFSIZE];
 137
 138         file = popen(cmd, "r");
 139         if (!file) {
 140                 pr_err("ERROR: unable to popen cmd: %s\n",
 141                        str_error_r(errno, serr, sizeof(serr)));
 142                 return -EINVAL;
 143         }
 144
 145         while (!feof(file) && !ferror(file)) {
 146                 /*
 147                  * Make buf_sz always have obe byte extra space so we
 148                  * can put '\0' there.
 149                  */
 150                 if (buf_sz - read_sz < READ_SIZE + 1) {
 151                         void *new_buf;
 152
 153                         buf_sz = read_sz + READ_SIZE + 1;
 154                         new_buf = realloc(buf, buf_sz);
 155
 156                         if (!new_buf) {
 157                                 pr_err("ERROR: failed to realloc memory\n");
 158                                 err = -ENOMEM;
 159                                 goto errout;
 160                         }
 161
 162                         buf = new_buf;
 163                 }
 164                 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
 165         }
 166
 167         if (buf_sz - read_sz < 1) {
 168                 pr_err("ERROR: internal error\n");
 169                 err = -EINVAL;
 170                 goto errout;
 171         }
 172
 173         if (ferror(file)) {
 174                 pr_err("ERROR: error occurred when reading from pipe: %s\n",
 175                        str_error_r(errno, serr, sizeof(serr)));
 176                 err = -EIO;
 177                 goto errout;
 178         }
 179
 180         err = WEXITSTATUS(pclose(file));
 181         file = NULL;
 182         if (err) {
 183                 err = -EINVAL;
 184                 goto errout;
 185         }
 186
 187         /*
 188          * If buf is string, give it terminal '\0' to make our life
 189          * easier. If buf is not string, that '\0' is out of space
 190          * indicated by read_sz so caller won't even notice it.
 191          */
 192         ((char *)buf)[read_sz] = '\0';
 193
 194         if (!p_buf)
 195                 free(buf);
 196         else
 197                 *p_buf = buf;
 198
 199         if (p_read_sz)
 200                 *p_read_sz = read_sz;
 201         return 0;
 202
 203 errout:
 204         if (file)
 205                 pclose(file);
 206         free(buf);
 207         if (p_buf)
 208                 *p_buf = NULL;
 209         if (p_read_sz)
 210                 *p_read_sz = 0;
 211         return err;
 212 }
 213
 214 static inline void
 215 force_set_env(const char *var, const char *value)
 216 {
 217         if (value) {
 218                 setenv(var, value, 1);
 219                 pr_debug("set env: %s=%s\n", var, value);
 220         } else {
 221                 unsetenv(var);
 222                 pr_debug("unset env: %s\n", var);
 223         }
 224 }
 225
 226 static void
 227 version_notice(void)
 228 {
 229         pr_err(
 230 "     \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
 231 "     \tYou may want to try git trunk:\n"
 232 "     \t\tgit clone http://llvm.org/git/llvm.git\n"
 233 "     \t\t     and\n"
 234 "     \t\tgit clone http://llvm.org/git/clang.git\n\n"
 235 "     \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
 236 "     \tdebian/ubuntu:\n"
 237 "     \t\thttps://apt.llvm.org/\n\n"
 238 "     \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
 239 "     \toption in [llvm] section of ~/.perfconfig to:\n\n"
 240 "     \t  \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
 241 "     \t     -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
 242 "     \t     -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
 243 "     \t(Replace /path/to/llc with path to your llc)\n\n"
 244 );
 245 }
 246
 247 static int detect_kbuild_dir(char **kbuild_dir)
 248 {
 249         const char *test_dir = llvm_param.kbuild_dir;
 250         const char *prefix_dir = "";
 251         const char *suffix_dir = "";
 252
 253         /* _UTSNAME_LENGTH is 65 */
 254         char release[128];
 255
 256         char *autoconf_path;
 257
 258         int err;
 259
 260         if (!test_dir) {
 261                 err = fetch_kernel_version(NULL, release,
 262                                            sizeof(release));
 263                 if (err)
 264                         return -EINVAL;
 265
 266                 test_dir = release;
 267                 prefix_dir = "/lib/modules/";
 268                 suffix_dir = "/build";
 269         }
 270
 271         err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
 272                        prefix_dir, test_dir, suffix_dir);
 273         if (err < 0)
 274                 return -ENOMEM;
 275
 276         if (access(autoconf_path, R_OK) == 0) {
 277                 free(autoconf_path);
 278
 279                 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
 280                                suffix_dir);
 281                 if (err < 0)
 282                         return -ENOMEM;
 283                 return 0;
 284         }
 285         pr_debug("%s: Couldn't find \"%s\", missing kernel-devel package?.\n",
 286                  __func__, autoconf_path);
 287         free(autoconf_path);
 288         return -ENOENT;
 289 }
 290
 291 static const char *kinc_fetch_script =
 292 "#!/usr/bin/env sh\n"
 293 "if ! test -d \"$KBUILD_DIR\"\n"
 294 "then\n"
 295 "       exit 1\n"
 296 "fi\n"
 297 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
 298 "then\n"
 299 "       exit 1\n"
 300 "fi\n"
 301 "TMPDIR=`mktemp -d`\n"
 302 "if test -z \"$TMPDIR\"\n"
 303 "then\n"
 304 "    exit 1\n"
 305 "fi\n"
 306 "cat << EOF > $TMPDIR/Makefile\n"
 307 "obj-y := dummy.o\n"
 308 "\\$(obj)/%.o: \\$(src)/%.c\n"
 309 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
 310 "\t\\$(CC) -c -o \\$@ \\$<\n"
 311 "EOF\n"
 312 "touch $TMPDIR/dummy.c\n"
 313 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
 314 "RET=$?\n"
 315 "rm -rf $TMPDIR\n"
 316 "exit $RET\n";
 317
 318 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
 319 {
 320         static char *saved_kbuild_dir;
 321         static char *saved_kbuild_include_opts;
 322         int err;
 323
 324         if (!kbuild_dir || !kbuild_include_opts)
 325                 return;
 326
 327         *kbuild_dir = NULL;
 328         *kbuild_include_opts = NULL;
 329
 330         if (saved_kbuild_dir && saved_kbuild_include_opts &&
 331             !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
 332                 *kbuild_dir = strdup(saved_kbuild_dir);
 333                 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
 334
 335                 if (*kbuild_dir && *kbuild_include_opts)
 336                         return;
 337
 338                 zfree(kbuild_dir);
 339                 zfree(kbuild_include_opts);
 340                 /*
 341                  * Don't fall through: it may breaks saved_kbuild_dir and
 342                  * saved_kbuild_include_opts if detect them again when
 343                  * memory is low.
 344                  */
 345                 return;
 346         }
 347
 348         if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
 349                 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
 350                 pr_debug("Skip kbuild options detection.\n");
 351                 goto errout;
 352         }
 353
 354         err = detect_kbuild_dir(kbuild_dir);
 355         if (err) {
 356                 pr_warning(
 357 "WARNING:\tunable to get correct kernel building directory.\n"
 358 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
 359 "     \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
 360 "     \tdetection.\n\n");
 361                 goto errout;
 362         }
 363
 364         pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
 365         force_set_env("KBUILD_DIR", *kbuild_dir);
 366         force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
 367         err = read_from_pipe(kinc_fetch_script,
 368                              (void **)kbuild_include_opts,
 369                              NULL);
 370         if (err) {
 371                 pr_warning(
 372 "WARNING:\tunable to get kernel include directories from '%s'\n"
 373 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
 374 "     \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
 375 "     \toption in [llvm] to \"\" to suppress this detection.\n\n",
 376                         *kbuild_dir);
 377
 378                 zfree(kbuild_dir);
 379                 goto errout;
 380         }
 381
 382         pr_debug("include option is set to %s\n", *kbuild_include_opts);
 383
 384         saved_kbuild_dir = strdup(*kbuild_dir);
 385         saved_kbuild_include_opts = strdup(*kbuild_include_opts);
 386
 387         if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
 388                 zfree(&saved_kbuild_dir);
 389                 zfree(&saved_kbuild_include_opts);
 390         }
 391         return;
 392 errout:
 393         saved_kbuild_dir = ERR_PTR(-EINVAL);
 394         saved_kbuild_include_opts = ERR_PTR(-EINVAL);
 395 }
 396
 397 int llvm__get_nr_cpus(void)
 398 {
 399         static int nr_cpus_avail = 0;
 400         char serr[STRERR_BUFSIZE];
 401
 402         if (nr_cpus_avail > 0)
 403                 return nr_cpus_avail;
 404
 405         nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
 406         if (nr_cpus_avail <= 0) {
 407                 pr_err(
 408 "WARNING:\tunable to get available CPUs in this system: %s\n"
 409 "        \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
 410                 nr_cpus_avail = 128;
 411         }
 412         return nr_cpus_avail;
 413 }
 414
 415 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
 416 {
 417         char *obj_path = strdup(path);
 418         FILE *fp;
 419         char *p;
 420
 421         if (!obj_path) {
 422                 pr_warning("WARNING: Not enough memory, skip object dumping\n");
 423                 return;
 424         }
 425
 426         p = strrchr(obj_path, '.');
 427         if (!p || (strcmp(p, ".c") != 0)) {
 428                 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
 429                            obj_path);
 430                 goto out;
 431         }
 432
 433         p[1] = 'o';
 434         fp = fopen(obj_path, "wb");
 435         if (!fp) {
 436                 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
 437                            obj_path, strerror(errno));
 438                 goto out;
 439         }
 440
 441         pr_debug("LLVM: dumping %s\n", obj_path);
 442         if (fwrite(obj_buf, size, 1, fp) != 1)
 443                 pr_debug("WARNING: failed to write to file '%s': %s, skip object dumping\n", obj_path, strerror(errno));
 444         fclose(fp);
 445 out:
 446         free(obj_path);
 447 }
 448
 449 int llvm__compile_bpf(const char *path, void **p_obj_buf,
 450                       size_t *p_obj_buf_sz)
 451 {
 452         size_t obj_buf_sz;
 453         void *obj_buf = NULL;
 454         int err, nr_cpus_avail;
 455         unsigned int kernel_version;
 456         char linux_version_code_str[64];
 457         const char *clang_opt = llvm_param.clang_opt;
 458         char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
 459         char serr[STRERR_BUFSIZE];
 460         char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
 461              *perf_bpf_include_opts = NULL;
 462         const char *template = llvm_param.clang_bpf_cmd_template;
 463         char *pipe_template = NULL;
 464         const char *opts = llvm_param.opts;
 465         char *command_echo = NULL, *command_out;
 466         char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
 467
 468         if (path[0] != '-' && realpath(path, abspath) == NULL) {
 469                 err = errno;
 470                 pr_err("ERROR: problems with path %s: %s\n",
 471                        path, str_error_r(err, serr, sizeof(serr)));
 472                 return -err;
 473         }
 474
 475         if (!template)
 476                 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
 477
 478         err = search_program_and_warn(llvm_param.clang_path,
 479                              "clang", clang_path);
 480         if (err)
 481                 return -ENOENT;
 482
 483         /*
 484          * This is an optional work. Even it fail we can continue our
 485          * work. Needn't check error return.
 486          */
 487         llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
 488
 489         nr_cpus_avail = llvm__get_nr_cpus();
 490         snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
 491                  nr_cpus_avail);
 492
 493         if (fetch_kernel_version(&kernel_version, NULL, 0))
 494                 kernel_version = 0;
 495
 496         snprintf(linux_version_code_str, sizeof(linux_version_code_str),
 497                  "0x%x", kernel_version);
 498         if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
 499                 goto errout;
 500         force_set_env("NR_CPUS", nr_cpus_avail_str);
 501         force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
 502         force_set_env("CLANG_EXEC", clang_path);
 503         force_set_env("CLANG_OPTIONS", clang_opt);
 504         force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
 505         force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
 506         force_set_env("WORKING_DIR", kbuild_dir ? : ".");
 507
 508         if (opts) {
 509                 err = search_program_and_warn(llvm_param.llc_path, "llc", llc_path);
 510                 if (err)
 511                         goto errout;
 512
 513                 err = -ENOMEM;
 514                 if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
 515                               template, llc_path, opts) < 0) {
 516                         pr_err("ERROR:\tnot enough memory to setup command line\n");
 517                         goto errout;
 518                 }
 519
 520                 template = pipe_template;
 521
 522         }
 523
 524         /*
 525          * Since we may reset clang's working dir, path of source file
 526          * should be transferred into absolute path, except we want
 527          * stdin to be source file (testing).
 528          */
 529         force_set_env("CLANG_SOURCE",
 530                       (path[0] == '-') ? path : abspath);
 531
 532         pr_debug("llvm compiling command template: %s\n", template);
 533
 534         err = -ENOMEM;
 535         if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
 536                 goto errout;
 537
 538         err = read_from_pipe(command_echo, (void **) &command_out, NULL);
 539         if (err)
 540                 goto errout;
 541
 542         pr_debug("llvm compiling command : %s\n", command_out);
 543
 544         err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
 545         if (err) {
 546                 pr_err("ERROR:\tunable to compile %s\n", path);
 547                 pr_err("Hint:\tCheck error message shown above.\n");
 548                 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
 549                 pr_err("     \t\tclang -target bpf -O2 -c %s\n", path);
 550                 pr_err("     \twith proper -I and -D options.\n");
 551                 goto errout;
 552         }
 553
 554         free(command_echo);
 555         free(command_out);
 556         free(kbuild_dir);
 557         free(kbuild_include_opts);
 558         free(perf_bpf_include_opts);
 559         free(perf_include_dir);
 560
 561         if (!p_obj_buf)
 562                 free(obj_buf);
 563         else
 564                 *p_obj_buf = obj_buf;
 565
 566         if (p_obj_buf_sz)
 567                 *p_obj_buf_sz = obj_buf_sz;
 568         return 0;
 569 errout:
 570         free(command_echo);
 571         free(kbuild_dir);
 572         free(kbuild_include_opts);
 573         free(obj_buf);
 574         free(perf_bpf_include_opts);
 575         free(perf_include_dir);
 576         free(pipe_template);
 577         if (p_obj_buf)
 578                 *p_obj_buf = NULL;
 579         if (p_obj_buf_sz)
 580                 *p_obj_buf_sz = 0;
 581         return err;
 582 }
 583
 584 int llvm__search_clang(void)
 585 {
 586         char clang_path[PATH_MAX];
 587
 588         return search_program_and_warn(llvm_param.clang_path, "clang", clang_path);
 589 }