/********************************************************************** mjit_worker.c - Worker for MRI method JIT compiler Copyright (C) 2017 Vladimir Makarov . **********************************************************************/ // NOTE: All functions in this file are executed on MJIT worker. So don't // call Ruby methods (C functions that may call rb_funcall) or trigger // GC (using ZALLOC, xmalloc, xfree, etc.) in this file. /* However, note that calling `free` for resources `xmalloc`-ed in mjit.c, which is currently done in some places, is sometimes problematic in the following situations: * malloc library could be different between interpreter and extensions on Windows (perhaps not applicable to MJIT because CC is the same) * xmalloc -> free leaks extra space used for USE_GC_MALLOC_OBJ_INFO_DETAILS (not enabled by default) ...in short, it's usually not a problem in MJIT. But maybe it's worth fixing for consistency or for USE_GC_MALLOC_OBJ_INFO_DETAILS support. */ /* We utilize widely used C compilers (GCC and LLVM Clang) to implement MJIT. We feed them a C code generated from ISEQ. The industrial C compilers are slower than regular JIT engines. Generated code performance of the used C compilers has a higher priority over the compilation speed. So our major goal is to minimize the ISEQ compilation time when we use widely optimization level (-O2). It is achieved by o Using a precompiled version of the header o Keeping all files in `/tmp`. On modern Linux `/tmp` is a file system in memory. So it is pretty fast o Implementing MJIT as a multi-threaded code because we want to compile ISEQs in parallel with iseq execution to speed up Ruby code execution. MJIT has one thread (*worker*) to do parallel compilations: o It prepares a precompiled code of the minimized header. It starts at the MRI execution start o It generates PIC object files of ISEQs o It takes one JIT unit from a priority queue unless it is empty. o It translates the JIT unit ISEQ into C-code using the precompiled header, calls CC and load PIC code when it is ready o Currently MJIT put ISEQ in the queue when ISEQ is called o MJIT can reorder ISEQs in the queue if some ISEQ has been called many times and its compilation did not start yet o MRI reuses the machine code if it already exists for ISEQ o The machine code we generate can stop and switch to the ISEQ interpretation if some condition is not satisfied as the machine code can be speculative or some exception raises o Speculative machine code can be canceled. Here is a diagram showing the MJIT organization: _______ |header | |_______| | MRI building --------------|---------------------------------------- | MRI execution | _____________|_____ | | | | ___V__ | CC ____________________ | | |----------->| precompiled header | | | | | |____________________| | | | | | | | MJIT | | | | | | | | | | | | ____V___ CC __________ | |______|----------->| C code |--->| .so file | | | |________| |__________| | | | | | | | MRI machine code |<----------------------------- |___________________| loading */ #ifdef __sun #define __EXTENSIONS__ 1 #endif #include "vm_core.h" #include "vm_callinfo.h" #include "mjit.h" #include "gc.h" #include "ruby_assert.h" #include "ruby/debug.h" #include "ruby/thread.h" #include "ruby/version.h" #ifdef _WIN32 #include #include #else #include #include #include #endif #include #ifdef HAVE_FCNTL_H #include #endif #ifdef HAVE_SYS_PARAM_H # include #endif #include "dln.h" #include "ruby/util.h" #undef strdup // ruby_strdup may trigger GC #ifndef MAXPATHLEN # define MAXPATHLEN 1024 #endif #ifdef _WIN32 #define dlopen(name,flag) ((void*)LoadLibrary(name)) #define dlerror() strerror(rb_w32_map_errno(GetLastError())) #define dlsym(handle,name) ((void*)GetProcAddress((handle),(name))) #define dlclose(handle) (!FreeLibrary(handle)) #define RTLD_NOW -1 #define waitpid(pid,stat_loc,options) (WaitForSingleObject((HANDLE)(pid), INFINITE), GetExitCodeProcess((HANDLE)(pid), (LPDWORD)(stat_loc)), CloseHandle((HANDLE)pid), (pid)) #define WIFEXITED(S) ((S) != STILL_ACTIVE) #define WEXITSTATUS(S) (S) #define WIFSIGNALED(S) (0) typedef intptr_t pid_t; #endif // Atomically set function pointer if possible. #define MJIT_ATOMIC_SET(var, val) (void)ATOMIC_PTR_EXCHANGE(var, val) #define MJIT_TMP_PREFIX "_ruby_mjit_" // JIT compaction requires the header transformation because linking multiple .o files // doesn't work without having `static` in the same function definitions. We currently // don't support transforming the MJIT header on Windows. #ifdef _WIN32 # define USE_JIT_COMPACTION 0 #else # define USE_JIT_COMPACTION 1 #endif // The unit structure that holds metadata of ISeq for MJIT. struct rb_mjit_unit { struct list_node unode; // Unique order number of unit. int id; // Dlopen handle of the loaded object file. void *handle; rb_iseq_t *iseq; #if defined(_WIN32) // DLL cannot be removed while loaded on Windows. If this is set, it'll be lazily deleted. char *so_file; #endif // Only used by unload_units. Flag to check this unit is currently on stack or not. bool used_code_p; // True if this is still in active_units but it's to be lazily removed bool stale_p; // mjit_compile's optimization switches struct rb_mjit_compile_info compile_info; // captured CC values, they should be marked with iseq. const struct rb_callcache **cc_entries; unsigned int cc_entries_size; // iseq->body->ci_size + ones of inlined iseqs }; // Linked list of struct rb_mjit_unit. struct rb_mjit_unit_list { struct list_head head; int length; // the list length }; extern void rb_native_mutex_lock(rb_nativethread_lock_t *lock); extern void rb_native_mutex_unlock(rb_nativethread_lock_t *lock); extern void rb_native_mutex_initialize(rb_nativethread_lock_t *lock); extern void rb_native_mutex_destroy(rb_nativethread_lock_t *lock); extern void rb_native_cond_initialize(rb_nativethread_cond_t *cond); extern void rb_native_cond_destroy(rb_nativethread_cond_t *cond); extern void rb_native_cond_signal(rb_nativethread_cond_t *cond); extern void rb_native_cond_broadcast(rb_nativethread_cond_t *cond); extern void rb_native_cond_wait(rb_nativethread_cond_t *cond, rb_nativethread_lock_t *mutex); // process.c extern rb_pid_t ruby_waitpid_locked(rb_vm_t *, rb_pid_t, int *status, int options, rb_nativethread_cond_t *cond); // A copy of MJIT portion of MRI options since MJIT initialization. We // need them as MJIT threads still can work when the most MRI data were // freed. struct mjit_options mjit_opts; // true if MJIT is enabled. bool mjit_enabled = false; // true if JIT-ed code should be called. When `ruby_vm_event_enabled_global_flags & ISEQ_TRACE_EVENTS` // and `mjit_call_p == false`, any JIT-ed code execution is cancelled as soon as possible. bool mjit_call_p = false; // Priority queue of iseqs waiting for JIT compilation. // This variable is a pointer to head unit of the queue. static struct rb_mjit_unit_list unit_queue = { LIST_HEAD_INIT(unit_queue.head) }; // List of units which are successfully compiled. static struct rb_mjit_unit_list active_units = { LIST_HEAD_INIT(active_units.head) }; // List of compacted so files which will be cleaned up by `free_list()` in `mjit_finish()`. static struct rb_mjit_unit_list compact_units = { LIST_HEAD_INIT(compact_units.head) }; // List of units before recompilation and just waiting for dlclose(). static struct rb_mjit_unit_list stale_units = { LIST_HEAD_INIT(stale_units.head) }; // The number of so far processed ISEQs, used to generate unique id. static int current_unit_num; // A mutex for conitionals and critical sections. static rb_nativethread_lock_t mjit_engine_mutex; // A thread conditional to wake up `mjit_finish` at the end of PCH thread. static rb_nativethread_cond_t mjit_pch_wakeup; // A thread conditional to wake up the client if there is a change in // executed unit status. static rb_nativethread_cond_t mjit_client_wakeup; // A thread conditional to wake up a worker if there we have something // to add or we need to stop MJIT engine. static rb_nativethread_cond_t mjit_worker_wakeup; // A thread conditional to wake up workers if at the end of GC. static rb_nativethread_cond_t mjit_gc_wakeup; // Greater than 0 when GC is working. static int in_gc = 0; // True when JIT is working. static bool in_jit = false; // True when active_units has at least one stale_p=true unit. static bool pending_stale_p = false; // The times when unload_units is requested. unload_units is called after some requests. static int unload_requests = 0; // The total number of unloaded units. static int total_unloads = 0; // Set to true to stop worker. static bool stop_worker_p; // Set to true if worker is stopped. static bool worker_stopped; // Path of "/tmp", which can be changed to $TMP in MinGW. static char *tmp_dir; // Hash like { 1 => true, 2 => true, ... } whose keys are valid `class_serial`s. // This is used to invalidate obsoleted CALL_CACHE. static VALUE valid_class_serials; // Used C compiler path. static const char *cc_path; // Used C compiler flags. static const char **cc_common_args; // Used C compiler flags added by --jit-debug=... static char **cc_added_args; // Name of the precompiled header file. static char *pch_file; // The process id which should delete the pch_file on mjit_finish. static rb_pid_t pch_owner_pid; // Status of the precompiled header creation. The status is // shared by the workers and the pch thread. static enum {PCH_NOT_READY, PCH_FAILED, PCH_SUCCESS} pch_status; #ifndef _MSC_VER // Name of the header file. static char *header_file; #endif #ifdef _WIN32 // Linker option to enable libruby. static char *libruby_pathflag; #endif #include "mjit_config.h" #if defined(__GNUC__) && \ (!defined(__clang__) || \ (defined(__clang__) && (defined(__FreeBSD__) || defined(__GLIBC__)))) # define GCC_PIC_FLAGS "-Wfatal-errors", "-fPIC", "-shared", "-w", "-pipe", # define MJIT_CFLAGS_PIPE 1 #else # define GCC_PIC_FLAGS /* empty */ # define MJIT_CFLAGS_PIPE 0 #endif // Use `-nodefaultlibs -nostdlib` for GCC where possible, which does not work on mingw, cygwin, AIX, and OpenBSD. // This seems to improve MJIT performance on GCC. #if defined __GNUC__ && !defined __clang__ && !defined(_WIN32) && !defined(__CYGWIN__) && !defined(_AIX) && !defined(__OpenBSD__) # define GCC_NOSTDLIB_FLAGS "-nodefaultlibs", "-nostdlib", #else # define GCC_NOSTDLIB_FLAGS // empty #endif static const char *const CC_COMMON_ARGS[] = { MJIT_CC_COMMON MJIT_CFLAGS GCC_PIC_FLAGS NULL }; static const char *const CC_DEBUG_ARGS[] = {MJIT_DEBUGFLAGS NULL}; static const char *const CC_OPTIMIZE_ARGS[] = {MJIT_OPTFLAGS NULL}; static const char *const CC_LDSHARED_ARGS[] = {MJIT_LDSHARED GCC_PIC_FLAGS NULL}; static const char *const CC_DLDFLAGS_ARGS[] = {MJIT_DLDFLAGS NULL}; // `CC_LINKER_ARGS` are linker flags which must be passed to `-c` as well. static const char *const CC_LINKER_ARGS[] = { #if defined __GNUC__ && !defined __clang__ && !defined(__OpenBSD__) "-nostartfiles", #endif GCC_NOSTDLIB_FLAGS NULL }; static const char *const CC_LIBS[] = { #if defined(_WIN32) || defined(__CYGWIN__) MJIT_LIBS // mswin, mingw, cygwin #endif #if defined __GNUC__ && !defined __clang__ # if defined(_WIN32) "-lmsvcrt", // mingw # endif "-lgcc", // mingw, cygwin, and GCC platforms using `-nodefaultlibs -nostdlib` #endif #if defined __ANDROID__ "-lm", // to avoid 'cannot locate symbol "modf" referenced by .../_ruby_mjit_XXX.so"' #endif NULL }; #define CC_CODEFLAG_ARGS (mjit_opts.debug ? CC_DEBUG_ARGS : CC_OPTIMIZE_ARGS) // Print the arguments according to FORMAT to stderr only if MJIT // verbose option value is more or equal to LEVEL. PRINTF_ARGS(static void, 2, 3) verbose(int level, const char *format, ...) { if (mjit_opts.verbose >= level) { va_list args; size_t len = strlen(format); char *full_format = alloca(sizeof(char) * (len + 2)); // Creating `format + '\n'` to atomically print format and '\n'. memcpy(full_format, format, len); full_format[len] = '\n'; full_format[len+1] = '\0'; va_start(args, format); vfprintf(stderr, full_format, args); va_end(args); } } PRINTF_ARGS(static void, 1, 2) mjit_warning(const char *format, ...) { if (mjit_opts.warnings || mjit_opts.verbose) { va_list args; fprintf(stderr, "MJIT warning: "); va_start(args, format); vfprintf(stderr, format, args); va_end(args); fprintf(stderr, "\n"); } } // Add unit node to the tail of doubly linked `list`. It should be not in // the list before. static void add_to_list(struct rb_mjit_unit *unit, struct rb_mjit_unit_list *list) { (void)RB_DEBUG_COUNTER_INC_IF(mjit_length_unit_queue, list == &unit_queue); (void)RB_DEBUG_COUNTER_INC_IF(mjit_length_active_units, list == &active_units); (void)RB_DEBUG_COUNTER_INC_IF(mjit_length_compact_units, list == &compact_units); (void)RB_DEBUG_COUNTER_INC_IF(mjit_length_stale_units, list == &stale_units); list_add_tail(&list->head, &unit->unode); list->length++; } static void remove_from_list(struct rb_mjit_unit *unit, struct rb_mjit_unit_list *list) { #if USE_DEBUG_COUNTER rb_debug_counter_add(RB_DEBUG_COUNTER_mjit_length_unit_queue, -1, list == &unit_queue); rb_debug_counter_add(RB_DEBUG_COUNTER_mjit_length_active_units, -1, list == &active_units); rb_debug_counter_add(RB_DEBUG_COUNTER_mjit_length_compact_units, -1, list == &compact_units); rb_debug_counter_add(RB_DEBUG_COUNTER_mjit_length_stale_units, -1, list == &stale_units); #endif list_del(&unit->unode); list->length--; } static void remove_file(const char *filename) { if (remove(filename)) { mjit_warning("failed to remove \"%s\": %s", filename, strerror(errno)); } } // Lazily delete .so files. static void clean_temp_files(struct rb_mjit_unit *unit) { #if defined(_WIN32) if (unit->so_file) { char *so_file = unit->so_file; unit->so_file = NULL; // unit->so_file is set only when mjit_opts.save_temps is false. remove_file(so_file); free(so_file); } #endif } // This is called in the following situations: // 1) On dequeue or `unload_units()`, associated ISeq is already GCed. // 2) The unit is not called often and unloaded by `unload_units()`. // 3) Freeing lists on `mjit_finish()`. // // `jit_func` value does not matter for 1 and 3 since the unit won't be used anymore. // For the situation 2, this sets the ISeq's JIT state to NOT_COMPILED_JIT_ISEQ_FUNC // to prevent the situation that the same methods are continuously compiled. static void free_unit(struct rb_mjit_unit *unit) { if (unit->iseq) { // ISeq is not GCed unit->iseq->body->jit_func = (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC; unit->iseq->body->jit_unit = NULL; } if (unit->cc_entries) { void *entries = (void *)unit->cc_entries; free(entries); } if (unit->handle && dlclose(unit->handle)) { // handle is NULL if it's in queue mjit_warning("failed to close handle for u%d: %s", unit->id, dlerror()); } clean_temp_files(unit); free(unit); } // Start a critical section. Use message `msg` to print debug info at `level`. static inline void CRITICAL_SECTION_START(int level, const char *msg) { verbose(level, "Locking %s", msg); rb_native_mutex_lock(&mjit_engine_mutex); verbose(level, "Locked %s", msg); } // Finish the current critical section. Use message `msg` to print // debug info at `level`. static inline void CRITICAL_SECTION_FINISH(int level, const char *msg) { verbose(level, "Unlocked %s", msg); rb_native_mutex_unlock(&mjit_engine_mutex); } static int sprint_uniq_filename(char *str, size_t size, unsigned long id, const char *prefix, const char *suffix) { return snprintf(str, size, "%s/%sp%"PRI_PIDT_PREFIX"uu%lu%s", tmp_dir, prefix, getpid(), id, suffix); } // Return time in milliseconds as a double. #ifdef __APPLE__ double ruby_real_ms_time(void); # define real_ms_time() ruby_real_ms_time() #else static double real_ms_time(void) { # ifdef HAVE_CLOCK_GETTIME struct timespec tv; # ifdef CLOCK_MONOTONIC const clockid_t c = CLOCK_MONOTONIC; # else const clockid_t c = CLOCK_REALTIME; # endif clock_gettime(c, &tv); return tv.tv_nsec / 1000000.0 + tv.tv_sec * 1000.0; # else struct timeval tv; gettimeofday(&tv, NULL); return tv.tv_usec / 1000.0 + tv.tv_sec * 1000.0; # endif } #endif // Return true if class_serial is not obsoleted. This is used by mjit_compile.c. bool mjit_valid_class_serial_p(rb_serial_t class_serial) { CRITICAL_SECTION_START(3, "in valid_class_serial_p"); bool found_p = rb_hash_stlike_lookup(valid_class_serials, LONG2FIX(class_serial), NULL); CRITICAL_SECTION_FINISH(3, "in valid_class_serial_p"); return found_p; } // Return the best unit from list. The best is the first // high priority unit or the unit whose iseq has the biggest number // of calls so far. static struct rb_mjit_unit * get_from_list(struct rb_mjit_unit_list *list) { while (in_gc) { verbose(3, "Waiting wakeup from GC"); rb_native_cond_wait(&mjit_gc_wakeup, &mjit_engine_mutex); } in_jit = true; // Lock GC // Find iseq with max total_calls struct rb_mjit_unit *unit = NULL, *next, *best = NULL; list_for_each_safe(&list->head, unit, next, unode) { if (unit->iseq == NULL) { // ISeq is GCed. remove_from_list(unit, list); free_unit(unit); continue; } if (best == NULL || best->iseq->body->total_calls < unit->iseq->body->total_calls) { best = unit; } } in_jit = false; // Unlock GC verbose(3, "Sending wakeup signal to client in a mjit-worker for GC"); rb_native_cond_signal(&mjit_client_wakeup); if (best) { remove_from_list(best, list); } return best; } // Return length of NULL-terminated array `args` excluding the NULL marker. static size_t args_len(char *const *args) { size_t i; for (i = 0; (args[i]) != NULL;i++) ; return i; } // Concatenate `num` passed NULL-terminated arrays of strings, put the // result (with NULL end marker) into the heap, and return the result. static char ** form_args(int num, ...) { va_list argp; size_t len, n; int i; char **args, **res, **tmp; va_start(argp, num); res = NULL; for (i = len = 0; i < num; i++) { args = va_arg(argp, char **); n = args_len(args); if ((tmp = (char **)realloc(res, sizeof(char *) * (len + n + 1))) == NULL) { free(res); res = NULL; break; } res = tmp; MEMCPY(res + len, args, char *, n + 1); len += n; } va_end(argp); return res; } COMPILER_WARNING_PUSH #if __has_warning("-Wdeprecated-declarations") || RBIMPL_COMPILER_IS(GCC) COMPILER_WARNING_IGNORED(-Wdeprecated-declarations) #endif // Start an OS process of absolute executable path with arguments `argv`. // Return PID of the process. static pid_t start_process(const char *abspath, char *const *argv) { // Not calling non-async-signal-safe functions between vfork // and execv for safety int dev_null = rb_cloexec_open(ruby_null_device, O_WRONLY, 0); if (dev_null < 0) { verbose(1, "MJIT: Failed to open a null device: %s", strerror(errno)); return -1; } if (mjit_opts.verbose >= 2) { const char *arg; fprintf(stderr, "Starting process: %s", abspath); for (int i = 0; (arg = argv[i]) != NULL; i++) fprintf(stderr, " %s", arg); fprintf(stderr, "\n"); } pid_t pid; #ifdef _WIN32 extern HANDLE rb_w32_start_process(const char *abspath, char *const *argv, int out_fd); int out_fd = 0; if (mjit_opts.verbose <= 1) { // Discard cl.exe's outputs like: // _ruby_mjit_p12u3.c // Creating library C:.../_ruby_mjit_p12u3.lib and object C:.../_ruby_mjit_p12u3.exp out_fd = dev_null; } pid = (pid_t)rb_w32_start_process(abspath, argv, out_fd); if (pid == 0) { verbose(1, "MJIT: Failed to create process: %s", dlerror()); return -1; } #else if ((pid = vfork()) == 0) { /* TODO: reuse some function in process.c */ umask(0077); if (mjit_opts.verbose == 0) { // CC can be started in a thread using a file which has been // already removed while MJIT is finishing. Discard the // messages about missing files. dup2(dev_null, STDERR_FILENO); dup2(dev_null, STDOUT_FILENO); } (void)close(dev_null); pid = execv(abspath, argv); // Pid will be negative on an error // Even if we successfully found CC to compile PCH we still can // fail with loading the CC in very rare cases for some reasons. // Stop the forked process in this case. verbose(1, "MJIT: Error in execv: %s", abspath); _exit(1); } #endif (void)close(dev_null); return pid; } COMPILER_WARNING_POP // Execute an OS process of executable PATH with arguments ARGV. // Return -1 or -2 if failed to execute, otherwise exit code of the process. // TODO: Use a similar function in process.c static int exec_process(const char *path, char *const argv[]) { int stat, exit_code = -2; rb_vm_t *vm = WAITPID_USE_SIGCHLD ? GET_VM() : 0; rb_nativethread_cond_t cond; if (vm) { rb_native_cond_initialize(&cond); rb_native_mutex_lock(&vm->waitpid_lock); } pid_t pid = start_process(path, argv); for (;pid > 0;) { pid_t r = vm ? ruby_waitpid_locked(vm, pid, &stat, 0, &cond) : waitpid(pid, &stat, 0); if (r == -1) { if (errno == EINTR) continue; fprintf(stderr, "[%"PRI_PIDT_PREFIX"d] waitpid(%lu): %s (SIGCHLD=%d,%u)\n", getpid(), (unsigned long)pid, strerror(errno), RUBY_SIGCHLD, SIGCHLD_LOSSY); break; } else if (r == pid) { if (WIFEXITED(stat)) { exit_code = WEXITSTATUS(stat); break; } else if (WIFSIGNALED(stat)) { exit_code = -1; break; } } } if (vm) { rb_native_mutex_unlock(&vm->waitpid_lock); rb_native_cond_destroy(&cond); } return exit_code; } static void remove_so_file(const char *so_file, struct rb_mjit_unit *unit) { #if defined(_WIN32) // Windows can't remove files while it's used. unit->so_file = strdup(so_file); // lazily delete on `clean_temp_files()` if (unit->so_file == NULL) mjit_warning("failed to allocate memory to lazily remove '%s': %s", so_file, strerror(errno)); #else remove_file(so_file); #endif } // Print _mjitX, but make a human-readable funcname when --jit-debug is used static void sprint_funcname(char *funcname, const struct rb_mjit_unit *unit) { const rb_iseq_t *iseq = unit->iseq; if (iseq == NULL || (!mjit_opts.debug && !mjit_opts.debug_flags)) { sprintf(funcname, "_mjit%d", unit->id); return; } // Generate a short path const char *path = RSTRING_PTR(rb_iseq_path(iseq)); const char *lib = "/lib/"; const char *version = "/" STRINGIZE(RUBY_API_VERSION_MAJOR) "." STRINGIZE(RUBY_API_VERSION_MINOR) "." STRINGIZE(RUBY_API_VERSION_TEENY) "/"; while (strstr(path, lib)) // skip "/lib/" path = strstr(path, lib) + strlen(lib); while (strstr(path, version)) // skip "/x.y.z/" path = strstr(path, version) + strlen(version); // Annotate all-normalized method names const char *method = RSTRING_PTR(iseq->body->location.label); if (!strcmp(method, "[]")) method = "AREF"; if (!strcmp(method, "[]=")) method = "ASET"; // Print and normalize sprintf(funcname, "_mjit%d_%s_%s", unit->id, path, method); for (size_t i = 0; i < strlen(funcname); i++) { char c = funcname[i]; if (!(('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || ('0' <= c && c <= '9') || c == '_')) { funcname[i] = '_'; } } } static const int c_file_access_mode = #ifdef O_BINARY O_BINARY| #endif O_WRONLY|O_EXCL|O_CREAT; #define append_str2(p, str, len) ((char *)memcpy((p), str, (len))+(len)) #define append_str(p, str) append_str2(p, str, sizeof(str)-1) #define append_lit(p, str) append_str2(p, str, rb_strlen_lit(str)) #ifdef _MSC_VER // Compile C file to so. It returns true if it succeeds. (mswin) static bool compile_c_to_so(const char *c_file, const char *so_file) { const char *files[] = { NULL, NULL, NULL, NULL, NULL, NULL, "-link", libruby_pathflag, NULL }; char *p; // files[0] = "-Fe*.dll" files[0] = p = alloca(sizeof(char) * (rb_strlen_lit("-Fe") + strlen(so_file) + 1)); p = append_lit(p, "-Fe"); p = append_str2(p, so_file, strlen(so_file)); *p = '\0'; // files[1] = "-Fo*.obj" // We don't need .obj file, but it's somehow created to cwd without -Fo and we want to control the output directory. files[1] = p = alloca(sizeof(char) * (rb_strlen_lit("-Fo") + strlen(so_file) - rb_strlen_lit(DLEXT) + rb_strlen_lit(".obj") + 1)); char *obj_file = p = append_lit(p, "-Fo"); p = append_str2(p, so_file, strlen(so_file) - rb_strlen_lit(DLEXT)); p = append_lit(p, ".obj"); *p = '\0'; // files[2] = "-Yu*.pch" files[2] = p = alloca(sizeof(char) * (rb_strlen_lit("-Yu") + strlen(pch_file) + 1)); p = append_lit(p, "-Yu"); p = append_str2(p, pch_file, strlen(pch_file)); *p = '\0'; // files[3] = "C:/.../rb_mjit_header-*.obj" files[3] = p = alloca(sizeof(char) * (strlen(pch_file) + 1)); p = append_str2(p, pch_file, strlen(pch_file) - strlen(".pch")); p = append_lit(p, ".obj"); *p = '\0'; // files[4] = "-Tc*.c" files[4] = p = alloca(sizeof(char) * (rb_strlen_lit("-Tc") + strlen(c_file) + 1)); p = append_lit(p, "-Tc"); p = append_str2(p, c_file, strlen(c_file)); *p = '\0'; // files[5] = "-Fd*.pdb" files[5] = p = alloca(sizeof(char) * (rb_strlen_lit("-Fd") + strlen(pch_file) + 1)); p = append_lit(p, "-Fd"); p = append_str2(p, pch_file, strlen(pch_file) - rb_strlen_lit(".pch")); p = append_lit(p, ".pdb"); *p = '\0'; char **args = form_args(5, CC_LDSHARED_ARGS, CC_CODEFLAG_ARGS, files, CC_LIBS, CC_DLDFLAGS_ARGS); if (args == NULL) return false; int exit_code = exec_process(cc_path, args); free(args); if (exit_code == 0) { // remove never-used files (.obj, .lib, .exp, .pdb). XXX: Is there any way not to generate this? if (!mjit_opts.save_temps) { char *before_dot; remove_file(obj_file); before_dot = obj_file + strlen(obj_file) - rb_strlen_lit(".obj"); append_lit(before_dot, ".lib"); remove_file(obj_file); append_lit(before_dot, ".exp"); remove_file(obj_file); append_lit(before_dot, ".pdb"); remove_file(obj_file); } } else { verbose(2, "compile_c_to_so: compile error: %d", exit_code); } return exit_code == 0; } #else // _MSC_VER // The function producing the pre-compiled header. static void make_pch(void) { const char *rest_args[] = { # ifdef __clang__ "-emit-pch", # endif // -nodefaultlibs is a linker flag, but it may affect cc1 behavior on Gentoo, which should NOT be changed on pch: // https://gitweb.gentoo.org/proj/gcc-patches.git/tree/7.3.0/gentoo/13_all_default-ssp-fix.patch GCC_NOSTDLIB_FLAGS "-o", pch_file, header_file, NULL, }; verbose(2, "Creating precompiled header"); char **args = form_args(4, cc_common_args, CC_CODEFLAG_ARGS, cc_added_args, rest_args); if (args == NULL) { mjit_warning("making precompiled header failed on forming args"); CRITICAL_SECTION_START(3, "in make_pch"); pch_status = PCH_FAILED; CRITICAL_SECTION_FINISH(3, "in make_pch"); return; } int exit_code = exec_process(cc_path, args); free(args); CRITICAL_SECTION_START(3, "in make_pch"); if (exit_code == 0) { pch_status = PCH_SUCCESS; } else { mjit_warning("Making precompiled header failed on compilation. Stopping MJIT worker..."); pch_status = PCH_FAILED; } /* wakeup `mjit_finish` */ rb_native_cond_broadcast(&mjit_pch_wakeup); CRITICAL_SECTION_FINISH(3, "in make_pch"); } // Compile .c file to .so file. It returns true if it succeeds. (non-mswin) // Not compiling .c to .so directly because it fails on MinGW, and this helps // to generate no .dSYM on macOS. static bool compile_c_to_so(const char *c_file, const char *so_file) { char* o_file = alloca(strlen(c_file) + 1); strcpy(o_file, c_file); o_file[strlen(c_file) - 1] = 'o'; const char *o_args[] = { "-o", o_file, c_file, # ifdef __clang__ "-include-pch", pch_file, # endif "-c", NULL }; char **args = form_args(5, cc_common_args, CC_CODEFLAG_ARGS, cc_added_args, o_args, CC_LINKER_ARGS); if (args == NULL) return false; int exit_code = exec_process(cc_path, args); free(args); if (exit_code != 0) { verbose(2, "compile_c_to_so: failed to compile .c to .o: %d", exit_code); return false; } const char *so_args[] = { "-o", so_file, # ifdef _WIN32 libruby_pathflag, # endif o_file, NULL }; args = form_args(6, CC_LDSHARED_ARGS, CC_CODEFLAG_ARGS, so_args, CC_LIBS, CC_DLDFLAGS_ARGS, CC_LINKER_ARGS); if (args == NULL) return false; exit_code = exec_process(cc_path, args); free(args); if (!mjit_opts.save_temps) remove_file(o_file); if (exit_code != 0) { verbose(2, "compile_c_to_so: failed to link .o to .so: %d", exit_code); } return exit_code == 0; } #endif // _MSC_VER #if USE_JIT_COMPACTION static void compile_prelude(FILE *f); static bool compile_compact_jit_code(char* c_file) { FILE *f; int fd = rb_cloexec_open(c_file, c_file_access_mode, 0600); if (fd < 0 || (f = fdopen(fd, "w")) == NULL) { int e = errno; if (fd >= 0) (void)close(fd); verbose(1, "Failed to fopen '%s', giving up JIT for it (%s)", c_file, strerror(e)); return false; } compile_prelude(f); // wait until mjit_gc_exit_hook is called CRITICAL_SECTION_START(3, "before mjit_compile to wait GC finish"); while (in_gc) { verbose(3, "Waiting wakeup from GC"); rb_native_cond_wait(&mjit_gc_wakeup, &mjit_engine_mutex); } // We need to check again here because we could've waited on GC above bool iseq_gced = false; struct rb_mjit_unit *child_unit = 0, *next; list_for_each_safe(&active_units.head, child_unit, next, unode) { if (child_unit->iseq == NULL) { // ISeq is GC-ed iseq_gced = true; verbose(1, "JIT compaction: A method for JIT code u%d is obsoleted. Compaction will be skipped.", child_unit->id); remove_from_list(child_unit, &active_units); free_unit(child_unit); // unload it without waiting for throttled unload_units to retry compaction quickly } } in_jit = !iseq_gced; CRITICAL_SECTION_FINISH(3, "before mjit_compile to wait GC finish"); if (!in_jit) { fclose(f); if (!mjit_opts.save_temps) remove_file(c_file); return false; } // This entire loop lock GC so that we do not need to consider a case that // ISeq is GC-ed in a middle of re-compilation. It takes 3~4ms with 100 methods // on my machine. It's not too bad compared to compilation time of C (7200~8000ms), // but it might be larger if we use a larger --jit-max-cache. // // TODO: Consider using a more granular lock after we implement inlining across // compacted functions (not done yet). bool success = true; list_for_each(&active_units.head, child_unit, unode) { char funcname[MAXPATHLEN]; sprint_funcname(funcname, child_unit); long iseq_lineno = 0; if (FIXNUM_P(child_unit->iseq->body->location.first_lineno)) // FIX2INT may fallback to rb_num2long(), which is a method call and dangerous in MJIT worker. So using only FIX2LONG. iseq_lineno = FIX2LONG(child_unit->iseq->body->location.first_lineno); const char *sep = "@"; const char *iseq_label = RSTRING_PTR(child_unit->iseq->body->location.label); const char *iseq_path = RSTRING_PTR(rb_iseq_path(child_unit->iseq)); if (!iseq_label) iseq_label = sep = ""; fprintf(f, "\n/* %s%s%s:%ld */\n", iseq_label, sep, iseq_path, iseq_lineno); success &= mjit_compile(f, child_unit->iseq, funcname, child_unit->id); } // release blocking mjit_gc_start_hook CRITICAL_SECTION_START(3, "after mjit_compile to wakeup client for GC"); in_jit = false; verbose(3, "Sending wakeup signal to client in a mjit-worker for GC"); rb_native_cond_signal(&mjit_client_wakeup); CRITICAL_SECTION_FINISH(3, "in worker to wakeup client for GC"); fclose(f); return success; } // Compile all cached .c files and build a single .so file. Reload all JIT func from it. // This improves the code locality for better performance in terms of iTLB and iCache. static void compact_all_jit_code(void) { struct rb_mjit_unit *unit, *cur = 0; static const char c_ext[] = ".c"; static const char so_ext[] = DLEXT; char c_file[MAXPATHLEN], so_file[MAXPATHLEN]; // Abnormal use case of rb_mjit_unit that doesn't have ISeq unit = calloc(1, sizeof(struct rb_mjit_unit)); // To prevent GC, don't use ZALLOC if (unit == NULL) return; unit->id = current_unit_num++; sprint_uniq_filename(c_file, (int)sizeof(c_file), unit->id, MJIT_TMP_PREFIX, c_ext); sprint_uniq_filename(so_file, (int)sizeof(so_file), unit->id, MJIT_TMP_PREFIX, so_ext); bool success = compile_compact_jit_code(c_file); double start_time = real_ms_time(); if (success) { success = compile_c_to_so(c_file, so_file); if (!mjit_opts.save_temps) remove_file(c_file); } double end_time = real_ms_time(); if (success) { void *handle = dlopen(so_file, RTLD_NOW); if (handle == NULL) { mjit_warning("failure in loading code from compacted '%s': %s", so_file, dlerror()); free(unit); return; } unit->handle = handle; // lazily dlclose handle (and .so file for win32) on `mjit_finish()`. add_to_list(unit, &compact_units); if (!mjit_opts.save_temps) remove_so_file(so_file, unit); CRITICAL_SECTION_START(3, "in compact_all_jit_code to read list"); list_for_each(&active_units.head, cur, unode) { void *func; char funcname[MAXPATHLEN]; sprint_funcname(funcname, cur); if ((func = dlsym(handle, funcname)) == NULL) { mjit_warning("skipping to reload '%s' from '%s': %s", funcname, so_file, dlerror()); continue; } if (cur->iseq) { // Check whether GCed or not // Usage of jit_code might be not in a critical section. MJIT_ATOMIC_SET(cur->iseq->body->jit_func, (mjit_func_t)func); } } CRITICAL_SECTION_FINISH(3, "in compact_all_jit_code to read list"); verbose(1, "JIT compaction (%.1fms): Compacted %d methods %s -> %s", end_time - start_time, active_units.length, c_file, so_file); } else { free(unit); verbose(1, "JIT compaction failure (%.1fms): Failed to compact methods", end_time - start_time); } } #endif // USE_JIT_COMPACTION static void * load_func_from_so(const char *so_file, const char *funcname, struct rb_mjit_unit *unit) { void *handle, *func; handle = dlopen(so_file, RTLD_NOW); if (handle == NULL) { mjit_warning("failure in loading code from '%s': %s", so_file, dlerror()); return (void *)NOT_ADDED_JIT_ISEQ_FUNC; } func = dlsym(handle, funcname); unit->handle = handle; return func; } #ifndef __clang__ static const char * header_name_end(const char *s) { const char *e = s + strlen(s); # ifdef __GNUC__ // don't chomp .pch for mswin static const char suffix[] = ".gch"; // chomp .gch suffix if (e > s+sizeof(suffix)-1 && strcmp(e-sizeof(suffix)+1, suffix) == 0) { e -= sizeof(suffix)-1; } # endif return e; } #endif // Print platform-specific prerequisites in generated code. static void compile_prelude(FILE *f) { #ifndef __clang__ // -include-pch is used for Clang const char *s = pch_file; const char *e = header_name_end(s); fprintf(f, "#include \""); // print pch_file except .gch for gcc, but keep .pch for mswin for (; s < e; s++) { switch(*s) { case '\\': case '"': fputc('\\', f); } fputc(*s, f); } fprintf(f, "\"\n"); #endif #ifdef _WIN32 fprintf(f, "void _pei386_runtime_relocator(void){}\n"); fprintf(f, "int __stdcall DllMainCRTStartup(void* hinstDLL, unsigned int fdwReason, void* lpvReserved) { return 1; }\n"); #endif } // Compile ISeq in UNIT and return function pointer of JIT-ed code. // It may return NOT_COMPILED_JIT_ISEQ_FUNC if something went wrong. static mjit_func_t convert_unit_to_func(struct rb_mjit_unit *unit) { static const char c_ext[] = ".c"; static const char so_ext[] = DLEXT; char c_file[MAXPATHLEN], so_file[MAXPATHLEN], funcname[MAXPATHLEN]; sprint_uniq_filename(c_file, (int)sizeof(c_file), unit->id, MJIT_TMP_PREFIX, c_ext); sprint_uniq_filename(so_file, (int)sizeof(so_file), unit->id, MJIT_TMP_PREFIX, so_ext); sprint_funcname(funcname, unit); FILE *f; int fd = rb_cloexec_open(c_file, c_file_access_mode, 0600); if (fd < 0 || (f = fdopen(fd, "w")) == NULL) { int e = errno; if (fd >= 0) (void)close(fd); verbose(1, "Failed to fopen '%s', giving up JIT for it (%s)", c_file, strerror(e)); return (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC; } // print #include of MJIT header, etc. compile_prelude(f); // wait until mjit_gc_exit_hook is called CRITICAL_SECTION_START(3, "before mjit_compile to wait GC finish"); while (in_gc) { verbose(3, "Waiting wakeup from GC"); rb_native_cond_wait(&mjit_gc_wakeup, &mjit_engine_mutex); } // We need to check again here because we could've waited on GC above in_jit = (unit->iseq != NULL); CRITICAL_SECTION_FINISH(3, "before mjit_compile to wait GC finish"); if (!in_jit) { fclose(f); if (!mjit_opts.save_temps) remove_file(c_file); return (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC; } // To make MJIT worker thread-safe against GC.compact, copy ISeq values while `in_jit` is true. long iseq_lineno = 0; if (FIXNUM_P(unit->iseq->body->location.first_lineno)) // FIX2INT may fallback to rb_num2long(), which is a method call and dangerous in MJIT worker. So using only FIX2LONG. iseq_lineno = FIX2LONG(unit->iseq->body->location.first_lineno); char *iseq_label = alloca(RSTRING_LEN(unit->iseq->body->location.label) + 1); char *iseq_path = alloca(RSTRING_LEN(rb_iseq_path(unit->iseq)) + 1); strcpy(iseq_label, RSTRING_PTR(unit->iseq->body->location.label)); strcpy(iseq_path, RSTRING_PTR(rb_iseq_path(unit->iseq))); verbose(2, "start compilation: %s@%s:%ld -> %s", iseq_label, iseq_path, iseq_lineno, c_file); fprintf(f, "/* %s@%s:%ld */\n\n", iseq_label, iseq_path, iseq_lineno); bool success = mjit_compile(f, unit->iseq, funcname, unit->id); // release blocking mjit_gc_start_hook CRITICAL_SECTION_START(3, "after mjit_compile to wakeup client for GC"); in_jit = false; verbose(3, "Sending wakeup signal to client in a mjit-worker for GC"); rb_native_cond_signal(&mjit_client_wakeup); CRITICAL_SECTION_FINISH(3, "in worker to wakeup client for GC"); fclose(f); if (!success) { if (!mjit_opts.save_temps) remove_file(c_file); verbose(1, "JIT failure: %s@%s:%ld -> %s", iseq_label, iseq_path, iseq_lineno, c_file); return (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC; } double start_time = real_ms_time(); success = compile_c_to_so(c_file, so_file); if (!mjit_opts.save_temps) remove_file(c_file); double end_time = real_ms_time(); if (!success) { verbose(2, "Failed to generate so: %s", so_file); return (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC; } void *func = load_func_from_so(so_file, funcname, unit); if (!mjit_opts.save_temps) remove_so_file(so_file, unit); if ((uintptr_t)func > (uintptr_t)LAST_JIT_ISEQ_FUNC) { verbose(1, "JIT success (%.1fms): %s@%s:%ld -> %s", end_time - start_time, iseq_label, iseq_path, iseq_lineno, c_file); } return (mjit_func_t)func; } // To see cc_entries using index returned by `mjit_capture_cc_entries` in mjit_compile.c const struct rb_callcache ** mjit_iseq_cc_entries(const struct rb_iseq_constant_body *const body) { return body->jit_unit->cc_entries; } // Capture cc entries of `captured_iseq` and append them to `compiled_iseq->jit_unit->cc_entries`. // This is needed when `captured_iseq` is inlined by `compiled_iseq` and GC needs to mark inlined cc. // // Index to refer to `compiled_iseq->jit_unit->cc_entries` is returned instead of the address // because old addresses may be invalidated by `realloc` later. -1 is returned on failure. // // This assumes that it's safe to reference cc without acquiring GVL. int mjit_capture_cc_entries(const struct rb_iseq_constant_body *compiled_iseq, const struct rb_iseq_constant_body *captured_iseq) { struct rb_mjit_unit *unit = compiled_iseq->jit_unit; unsigned int new_entries_size = unit->cc_entries_size + captured_iseq->ci_size; VM_ASSERT(captured_iseq->ci_size > 0); // Allocate new cc_entries and append them to unit->cc_entries const struct rb_callcache **cc_entries; int cc_entries_index = unit->cc_entries_size; if (unit->cc_entries_size == 0) { VM_ASSERT(unit->cc_entries == NULL); unit->cc_entries = cc_entries = malloc(sizeof(struct rb_callcache *) * new_entries_size); if (cc_entries == NULL) return -1; } else { void *cc_ptr = (void *)unit->cc_entries; // get rid of bogus warning by VC cc_entries = realloc(cc_ptr, sizeof(struct rb_callcache *) * new_entries_size); if (cc_entries == NULL) return -1; unit->cc_entries = cc_entries; cc_entries += cc_entries_index; } unit->cc_entries_size = new_entries_size; // Capture cc to cc_enties for (unsigned int i = 0; i < captured_iseq->ci_size; i++) { cc_entries[i] = captured_iseq->call_data[i].cc; } return cc_entries_index; } // Set up field `used_code_p` for unit iseqs whose iseq on the stack of ec. static void mark_ec_units(rb_execution_context_t *ec) { const rb_control_frame_t *cfp; if (ec->vm_stack == NULL) return; for (cfp = RUBY_VM_END_CONTROL_FRAME(ec) - 1; ; cfp = RUBY_VM_NEXT_CONTROL_FRAME(cfp)) { const rb_iseq_t *iseq; if (cfp->pc && (iseq = cfp->iseq) != NULL && imemo_type((VALUE) iseq) == imemo_iseq && (iseq->body->jit_unit) != NULL) { iseq->body->jit_unit->used_code_p = true; } if (cfp == ec->cfp) break; // reached the most recent cfp } } // MJIT info related to an existing continutaion. struct mjit_cont { rb_execution_context_t *ec; // continuation ec struct mjit_cont *prev, *next; // used to form lists }; // Double linked list of registered continuations. This is used to detect // units which are in use in unload_units. static struct mjit_cont *first_cont; // Unload JIT code of some units to satisfy the maximum permitted // number of units with a loaded code. static void unload_units(void) { struct rb_mjit_unit *unit = 0, *next; struct mjit_cont *cont; int units_num = active_units.length; // For now, we don't unload units when ISeq is GCed. We should // unload such ISeqs first here. list_for_each_safe(&active_units.head, unit, next, unode) { if (unit->iseq == NULL) { // ISeq is GCed. remove_from_list(unit, &active_units); free_unit(unit); } } // Detect units which are in use and can't be unloaded. list_for_each(&active_units.head, unit, unode) { assert(unit->iseq != NULL && unit->handle != NULL); unit->used_code_p = false; } // All threads have a root_fiber which has a mjit_cont. Other normal fibers also // have a mjit_cont. Thus we can check ISeqs in use by scanning ec of mjit_conts. for (cont = first_cont; cont != NULL; cont = cont->next) { mark_ec_units(cont->ec); } // TODO: check stale_units and unload unused ones! (note that the unit is not associated to ISeq anymore) // Unload units whose total_calls is smaller than any total_calls in unit_queue. // TODO: make the algorithm more efficient long unsigned prev_queue_calls = -1; while (true) { // Calculate the next max total_calls in unit_queue long unsigned max_queue_calls = 0; list_for_each(&unit_queue.head, unit, unode) { if (unit->iseq != NULL && max_queue_calls < unit->iseq->body->total_calls && unit->iseq->body->total_calls < prev_queue_calls) { max_queue_calls = unit->iseq->body->total_calls; } } prev_queue_calls = max_queue_calls; bool unloaded_p = false; list_for_each_safe(&active_units.head, unit, next, unode) { if (unit->used_code_p) // We can't unload code on stack. continue; if (max_queue_calls > unit->iseq->body->total_calls) { verbose(2, "Unloading unit %d (calls=%lu, threshold=%lu)", unit->id, unit->iseq->body->total_calls, max_queue_calls); assert(unit->handle != NULL); remove_from_list(unit, &active_units); free_unit(unit); unloaded_p = true; } } if (!unloaded_p) break; } if (units_num > active_units.length) { verbose(1, "Too many JIT code -- %d units unloaded", units_num - active_units.length); total_unloads += units_num - active_units.length; } } // The function implementing a worker. It is executed in a separate // thread by rb_thread_create_mjit_thread. It compiles precompiled header // and then compiles requested ISeqs. void mjit_worker(void) { // Allow only `max_cache_size / 10` times (default: 10) of compaction. // Note: GC of compacted code has not been implemented yet. int max_compact_size = mjit_opts.max_cache_size / 10; if (max_compact_size < 10) max_compact_size = 10; // Run unload_units after it's requested `max_cache_size / 10` (default: 10) times. // This throttles the call to mitigate locking in unload_units. It also throttles JIT compaction. int throttle_threshold = mjit_opts.max_cache_size / 10; #ifndef _MSC_VER if (pch_status == PCH_NOT_READY) { make_pch(); } #endif if (pch_status == PCH_FAILED) { mjit_enabled = false; CRITICAL_SECTION_START(3, "in worker to update worker_stopped"); worker_stopped = true; verbose(3, "Sending wakeup signal to client in a mjit-worker"); rb_native_cond_signal(&mjit_client_wakeup); CRITICAL_SECTION_FINISH(3, "in worker to update worker_stopped"); return; // TODO: do the same thing in the latter half of mjit_finish } // main worker loop while (!stop_worker_p) { struct rb_mjit_unit *unit; // Wait until a unit becomes available CRITICAL_SECTION_START(3, "in worker dequeue"); while ((pending_stale_p || list_empty(&unit_queue.head) || active_units.length >= mjit_opts.max_cache_size) && !stop_worker_p) { rb_native_cond_wait(&mjit_worker_wakeup, &mjit_engine_mutex); verbose(3, "Getting wakeup from client"); // Lazily move active_units to stale_units to avoid race conditions around active_units with compaction if (pending_stale_p) { pending_stale_p = false; struct rb_mjit_unit *next; list_for_each_safe(&active_units.head, unit, next, unode) { if (unit->stale_p) { unit->stale_p = false; remove_from_list(unit, &active_units); add_to_list(unit, &stale_units); } } } // Unload some units as needed if (unload_requests >= throttle_threshold) { while (in_gc) { verbose(3, "Waiting wakeup from GC"); rb_native_cond_wait(&mjit_gc_wakeup, &mjit_engine_mutex); } in_jit = true; // Lock GC RB_DEBUG_COUNTER_INC(mjit_unload_units); unload_units(); unload_requests = 0; in_jit = false; // Unlock GC verbose(3, "Sending wakeup signal to client in a mjit-worker for GC"); rb_native_cond_signal(&mjit_client_wakeup); } if (active_units.length == mjit_opts.max_cache_size && mjit_opts.wait) { // Sometimes all methods may be in use mjit_opts.max_cache_size++; // avoid infinite loop on `rb_mjit_wait_call`. Note that --jit-wait is just for testing. verbose(1, "No units can be unloaded -- incremented max-cache-size to %d for --jit-wait", mjit_opts.max_cache_size); } } unit = get_from_list(&unit_queue); CRITICAL_SECTION_FINISH(3, "in worker dequeue"); if (unit) { // JIT compile mjit_func_t func = convert_unit_to_func(unit); (void)RB_DEBUG_COUNTER_INC_IF(mjit_compile_failures, func == (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC); CRITICAL_SECTION_START(3, "in jit func replace"); while (in_gc) { // Make sure we're not GC-ing when touching ISeq verbose(3, "Waiting wakeup from GC"); rb_native_cond_wait(&mjit_gc_wakeup, &mjit_engine_mutex); } if (unit->iseq) { // Check whether GCed or not if ((uintptr_t)func > (uintptr_t)LAST_JIT_ISEQ_FUNC) { add_to_list(unit, &active_units); } // Usage of jit_code might be not in a critical section. MJIT_ATOMIC_SET(unit->iseq->body->jit_func, func); } else { free_unit(unit); } CRITICAL_SECTION_FINISH(3, "in jit func replace"); #if USE_JIT_COMPACTION // Combine .o files to one .so and reload all jit_func to improve memory locality. if (compact_units.length < max_compact_size && ((!mjit_opts.wait && unit_queue.length == 0 && active_units.length > 1) || (active_units.length == mjit_opts.max_cache_size && compact_units.length * throttle_threshold <= total_unloads))) { // throttle compaction by total_unloads compact_all_jit_code(); } #endif } } // To keep mutex unlocked when it is destroyed by mjit_finish, don't wrap CRITICAL_SECTION here. worker_stopped = true; }