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