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