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