tools/perf/util/llvm-utils.c

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