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ruby/mjit.c

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C
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/**********************************************************************
mjit.c - MRI method JIT compiler functions for Ruby's main thread
Copyright (C) 2017 Vladimir Makarov <vmakarov@redhat.com>.
**********************************************************************/
// Functions in this file are never executed on MJIT worker thread.
// So you can safely use Ruby methods and GC in this file.
// To share variables privately, include mjit_worker.c instead of linking.
#include "ruby/internal/config.h" // defines USE_MJIT
#if USE_MJIT
#include "constant.h"
#include "id_table.h"
#include "internal.h"
#include "internal/class.h"
#include "internal/cmdlineopt.h"
#include "internal/cont.h"
#include "internal/file.h"
#include "internal/hash.h"
#include "internal/warnings.h"
#include "vm_sync.h"
#include "mjit_worker.c"
extern int rb_thread_create_mjit_thread(void (*worker_func)(void));
// Return an unique file name in /tmp with PREFIX and SUFFIX and
// number ID. Use getpid if ID == 0. The return file name exists
// until the next function call.
static char *
get_uniq_filename(unsigned long id, const char *prefix, const char *suffix)
{
char buff[70], *str = buff;
int size = sprint_uniq_filename(buff, sizeof(buff), id, prefix, suffix);
str = 0;
++size;
str = xmalloc(size);
if (size <= (int)sizeof(buff)) {
memcpy(str, buff, size);
}
else {
sprint_uniq_filename(str, size, id, prefix, suffix);
}
return str;
}
// Wait until workers don't compile any iseq. It is called at the
// start of GC.
void
mjit_gc_start_hook(void)
{
if (!mjit_enabled)
return;
CRITICAL_SECTION_START(4, "mjit_gc_start_hook");
while (in_jit) {
verbose(4, "Waiting wakeup from a worker for GC");
rb_native_cond_wait(&mjit_client_wakeup, &mjit_engine_mutex);
verbose(4, "Getting wakeup from a worker for GC");
}
in_gc++;
CRITICAL_SECTION_FINISH(4, "mjit_gc_start_hook");
}
// Send a signal to workers to continue iseq compilations. It is
// called at the end of GC.
void
mjit_gc_exit_hook(void)
{
if (!mjit_enabled)
return;
CRITICAL_SECTION_START(4, "mjit_gc_exit_hook");
in_gc--;
RUBY_ASSERT_ALWAYS(in_gc >= 0);
if (!in_gc) {
verbose(4, "Sending wakeup signal to workers after GC");
rb_native_cond_broadcast(&mjit_gc_wakeup);
}
CRITICAL_SECTION_FINISH(4, "mjit_gc_exit_hook");
}
// Prohibit calling JIT-ed code and let existing JIT-ed frames exit before the next insn.
void
mjit_cancel_all(const char *reason)
{
if (!mjit_enabled)
return;
mjit_call_p = false;
if (mjit_opts.warnings || mjit_opts.verbose) {
fprintf(stderr, "JIT cancel: Disabled JIT-ed code because %s\n", reason);
}
}
// Deal with ISeq movement from compactor
void
mjit_update_references(const rb_iseq_t *iseq)
{
if (!mjit_enabled)
return;
CRITICAL_SECTION_START(4, "mjit_update_references");
if (ISEQ_BODY(iseq)->jit_unit) {
ISEQ_BODY(iseq)->jit_unit->iseq = (rb_iseq_t *)rb_gc_location((VALUE)ISEQ_BODY(iseq)->jit_unit->iseq);
// We need to invalidate JIT-ed code for the ISeq because it embeds pointer addresses.
// To efficiently do that, we use the same thing as TracePoint and thus everything is cancelled for now.
// See mjit.h and tool/ruby_vm/views/_mjit_compile_insn.erb for how `mjit_call_p` is used.
mjit_cancel_all("GC.compact is used"); // TODO: instead of cancelling all, invalidate only this one and recompile it with some threshold.
}
// Units in stale_units (list of over-speculated and invalidated code) are not referenced from
// `ISEQ_BODY(iseq)->jit_unit` anymore (because new one replaces that). So we need to check them too.
// TODO: we should be able to reduce the number of units checked here.
struct rb_mjit_unit *unit = NULL;
ccan_list_for_each(&stale_units.head, unit, unode) {
if (unit->iseq == iseq) {
unit->iseq = (rb_iseq_t *)rb_gc_location((VALUE)unit->iseq);
}
}
CRITICAL_SECTION_FINISH(4, "mjit_update_references");
}
// Iseqs can be garbage collected. This function should call when it
// happens. It removes iseq from the unit.
void
mjit_free_iseq(const rb_iseq_t *iseq)
{
if (!mjit_enabled)
return;
CRITICAL_SECTION_START(4, "mjit_free_iseq");
RUBY_ASSERT_ALWAYS(in_gc);
RUBY_ASSERT_ALWAYS(!in_jit);
if (ISEQ_BODY(iseq)->jit_unit) {
// jit_unit is not freed here because it may be referred by multiple
// lists of units. `get_from_list` and `mjit_finish` do the job.
ISEQ_BODY(iseq)->jit_unit->iseq = NULL;
}
// Units in stale_units (list of over-speculated and invalidated code) are not referenced from
// `ISEQ_BODY(iseq)->jit_unit` anymore (because new one replaces that). So we need to check them too.
// TODO: we should be able to reduce the number of units checked here.
struct rb_mjit_unit *unit = NULL;
ccan_list_for_each(&stale_units.head, unit, unode) {
if (unit->iseq == iseq) {
unit->iseq = NULL;
}
}
CRITICAL_SECTION_FINISH(4, "mjit_free_iseq");
}
// Free unit list. This should be called only when worker is finished
// because node of unit_queue and one of active_units may have the same unit
// during proceeding unit.
static void
free_list(struct rb_mjit_unit_list *list, bool close_handle_p)
{
struct rb_mjit_unit *unit = 0, *next;
ccan_list_for_each_safe(&list->head, unit, next, unode) {
ccan_list_del(&unit->unode);
if (!close_handle_p) unit->handle = NULL; /* Skip dlclose in free_unit() */
if (list == &stale_units) { // `free_unit(unit)` crashes after GC.compact on `stale_units`
/*
* TODO: REVERT THIS BRANCH
* Debug the crash on stale_units w/ GC.compact and just use `free_unit(unit)`!!
*/
if (unit->handle && dlclose(unit->handle)) {
mjit_warning("failed to close handle for u%d: %s", unit->id, dlerror());
}
clean_temp_files(unit);
free(unit);
}
else {
free_unit(unit);
}
}
list->length = 0;
}
// Register a new continuation with execution context `ec`. Return MJIT info about
// the continuation.
struct mjit_cont *
mjit_cont_new(rb_execution_context_t *ec)
{
struct mjit_cont *cont;
// We need to use calloc instead of something like ZALLOC to avoid triggering GC here.
// When this function is called from rb_thread_alloc through rb_threadptr_root_fiber_setup,
// the thread is still being prepared and marking it causes SEGV.
cont = calloc(1, sizeof(struct mjit_cont));
if (cont == NULL)
rb_memerror();
cont->ec = ec;
CRITICAL_SECTION_START(3, "in mjit_cont_new");
if (first_cont == NULL) {
cont->next = cont->prev = NULL;
}
else {
cont->prev = NULL;
cont->next = first_cont;
first_cont->prev = cont;
}
first_cont = cont;
CRITICAL_SECTION_FINISH(3, "in mjit_cont_new");
return cont;
}
// Unregister continuation `cont`.
void
mjit_cont_free(struct mjit_cont *cont)
{
CRITICAL_SECTION_START(3, "in mjit_cont_new");
if (cont == first_cont) {
first_cont = cont->next;
if (first_cont != NULL)
first_cont->prev = NULL;
}
else {
cont->prev->next = cont->next;
if (cont->next != NULL)
cont->next->prev = cont->prev;
}
CRITICAL_SECTION_FINISH(3, "in mjit_cont_new");
free(cont);
}
// Finish work with continuation info.
static void
finish_conts(void)
{
struct mjit_cont *cont, *next;
for (cont = first_cont; cont != NULL; cont = next) {
next = cont->next;
xfree(cont);
}
}
// Create unit for `iseq`. This function may be called from an MJIT worker.
static void
create_unit(const rb_iseq_t *iseq)
{
struct rb_mjit_unit *unit;
unit = calloc(1, sizeof(struct rb_mjit_unit));
if (unit == NULL)
return;
unit->id = current_unit_num++;
unit->iseq = (rb_iseq_t *)iseq;
ISEQ_BODY(iseq)->jit_unit = unit;
}
// Return true if given ISeq body should be compiled by MJIT
static inline int
mjit_target_iseq_p(struct rb_iseq_constant_body *body)
{
return (body->type == ISEQ_TYPE_METHOD || body->type == ISEQ_TYPE_BLOCK)
&& !body->builtin_inline_p;
}
// If recompile_p is true, the call is initiated by mjit_recompile.
// This assumes the caller holds CRITICAL_SECTION when recompile_p is true.
static void
mjit_add_iseq_to_process(const rb_iseq_t *iseq, const struct rb_mjit_compile_info *compile_info, bool recompile_p)
{
if (!mjit_enabled || pch_status == PCH_FAILED)
return;
if (!mjit_target_iseq_p(ISEQ_BODY(iseq))) {
ISEQ_BODY(iseq)->jit_func = (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC; // skip mjit_wait
return;
}
if (!recompile_p) {
CRITICAL_SECTION_START(3, "in add_iseq_to_process");
// This prevents multiple Ractors from enqueueing the same ISeq twice.
if (rb_multi_ractor_p() && (uintptr_t)ISEQ_BODY(iseq)->jit_func != NOT_ADDED_JIT_ISEQ_FUNC) {
CRITICAL_SECTION_FINISH(3, "in add_iseq_to_process");
return;
}
}
RB_DEBUG_COUNTER_INC(mjit_add_iseq_to_process);
ISEQ_BODY(iseq)->jit_func = (mjit_func_t)NOT_READY_JIT_ISEQ_FUNC;
create_unit(iseq);
if (ISEQ_BODY(iseq)->jit_unit == NULL)
// Failure in creating the unit.
return;
if (compile_info != NULL)
ISEQ_BODY(iseq)->jit_unit->compile_info = *compile_info;
add_to_list(ISEQ_BODY(iseq)->jit_unit, &unit_queue);
if (active_units.length >= mjit_opts.max_cache_size) {
unload_requests++;
}
if (!recompile_p) {
verbose(3, "Sending wakeup signal to workers in mjit_add_iseq_to_process");
rb_native_cond_broadcast(&mjit_worker_wakeup);
CRITICAL_SECTION_FINISH(3, "in add_iseq_to_process");
}
}
// Add ISEQ to be JITed in parallel with the current thread.
// Unload some JIT codes if there are too many of them.
void
rb_mjit_add_iseq_to_process(const rb_iseq_t *iseq)
{
mjit_add_iseq_to_process(iseq, NULL, false);
}
// For this timeout seconds, --jit-wait will wait for JIT compilation finish.
#define MJIT_WAIT_TIMEOUT_SECONDS 60
static void
mjit_wait(struct rb_iseq_constant_body *body)
{
struct timeval tv;
int tries = 0;
tv.tv_sec = 0;
tv.tv_usec = 1000;
while (body->jit_func == (mjit_func_t)NOT_READY_JIT_ISEQ_FUNC) {
tries++;
if (tries / 1000 > MJIT_WAIT_TIMEOUT_SECONDS || pch_status == PCH_FAILED) {
CRITICAL_SECTION_START(3, "in rb_mjit_wait_call to set jit_func");
body->jit_func = (mjit_func_t)NOT_COMPILED_JIT_ISEQ_FUNC; // JIT worker seems dead. Give up.
CRITICAL_SECTION_FINISH(3, "in rb_mjit_wait_call to set jit_func");
mjit_warning("timed out to wait for JIT finish");
break;
}
CRITICAL_SECTION_START(3, "in rb_mjit_wait_call for a client wakeup");
rb_native_cond_broadcast(&mjit_worker_wakeup);
CRITICAL_SECTION_FINISH(3, "in rb_mjit_wait_call for a client wakeup");
rb_thread_wait_for(tv);
}
}
// Wait for JIT compilation finish for --jit-wait, and call the function pointer
// if the compiled result is not NOT_COMPILED_JIT_ISEQ_FUNC.
VALUE
rb_mjit_wait_call(rb_execution_context_t *ec, struct rb_iseq_constant_body *body)
{
if (worker_stopped)
return Qundef;
mjit_wait(body);
if ((uintptr_t)body->jit_func <= (uintptr_t)LAST_JIT_ISEQ_FUNC) {
return Qundef;
}
return body->jit_func(ec, ec->cfp);
}
struct rb_mjit_compile_info*
rb_mjit_iseq_compile_info(const struct rb_iseq_constant_body *body)
{
assert(body->jit_unit != NULL);
return &body->jit_unit->compile_info;
}
static void
mjit_recompile(const rb_iseq_t *iseq)
{
if ((uintptr_t)ISEQ_BODY(iseq)->jit_func <= (uintptr_t)LAST_JIT_ISEQ_FUNC)
return;
verbose(1, "JIT recompile: %s@%s:%d", RSTRING_PTR(ISEQ_BODY(iseq)->location.label),
RSTRING_PTR(rb_iseq_path(iseq)), FIX2INT(ISEQ_BODY(iseq)->location.first_lineno));
assert(ISEQ_BODY(iseq)->jit_unit != NULL);
if (UNLIKELY(mjit_opts.wait)) {
CRITICAL_SECTION_START(3, "in rb_mjit_recompile_iseq");
remove_from_list(ISEQ_BODY(iseq)->jit_unit, &active_units);
add_to_list(ISEQ_BODY(iseq)->jit_unit, &stale_units);
mjit_add_iseq_to_process(iseq, &ISEQ_BODY(iseq)->jit_unit->compile_info, true);
CRITICAL_SECTION_FINISH(3, "in rb_mjit_recompile_iseq");
mjit_wait(ISEQ_BODY(iseq));
}
else {
// Lazily move active_units to stale_units to avoid race conditions around active_units with compaction.
// Also, it's lazily moved to unit_queue as well because otherwise it won't be added to stale_units properly.
// It's good to avoid a race condition between mjit_add_iseq_to_process and mjit_compile around jit_unit as well.
CRITICAL_SECTION_START(3, "in rb_mjit_recompile_iseq");
ISEQ_BODY(iseq)->jit_unit->stale_p = true;
ISEQ_BODY(iseq)->jit_func = (mjit_func_t)NOT_READY_JIT_ISEQ_FUNC;
pending_stale_p = true;
CRITICAL_SECTION_FINISH(3, "in rb_mjit_recompile_iseq");
}
}
// Recompile iseq, disabling send optimization
void
rb_mjit_recompile_send(const rb_iseq_t *iseq)
{
rb_mjit_iseq_compile_info(ISEQ_BODY(iseq))->disable_send_cache = true;
mjit_recompile(iseq);
}
// Recompile iseq, disabling ivar optimization
void
rb_mjit_recompile_ivar(const rb_iseq_t *iseq)
{
rb_mjit_iseq_compile_info(ISEQ_BODY(iseq))->disable_ivar_cache = true;
mjit_recompile(iseq);
}
// Recompile iseq, disabling exivar optimization
void
rb_mjit_recompile_exivar(const rb_iseq_t *iseq)
{
rb_mjit_iseq_compile_info(ISEQ_BODY(iseq))->disable_exivar_cache = true;
mjit_recompile(iseq);
}
// Recompile iseq, disabling method inlining
void
rb_mjit_recompile_inlining(const rb_iseq_t *iseq)
{
rb_mjit_iseq_compile_info(ISEQ_BODY(iseq))->disable_inlining = true;
mjit_recompile(iseq);
}
// Recompile iseq, disabling getconstant inlining
void
rb_mjit_recompile_const(const rb_iseq_t *iseq)
{
rb_mjit_iseq_compile_info(ISEQ_BODY(iseq))->disable_const_cache = true;
mjit_recompile(iseq);
}
extern VALUE ruby_archlibdir_path, ruby_prefix_path;
// Initialize header_file, pch_file, libruby_pathflag. Return true on success.
static bool
init_header_filename(void)
{
int fd;
#ifdef LOAD_RELATIVE
// Root path of the running ruby process. Equal to RbConfig::TOPDIR.
VALUE basedir_val;
#endif
const char *basedir = "";
size_t baselen = 0;
char *p;
#ifdef _WIN32
static const char libpathflag[] =
# ifdef _MSC_VER
"-LIBPATH:"
# else
"-L"
# endif
;
const size_t libpathflag_len = sizeof(libpathflag) - 1;
#endif
#ifdef LOAD_RELATIVE
basedir_val = ruby_prefix_path;
basedir = StringValuePtr(basedir_val);
baselen = RSTRING_LEN(basedir_val);
#else
if (getenv("MJIT_SEARCH_BUILD_DIR")) {
// This path is not intended to be used on production, but using build directory's
// header file here because people want to run `make test-all` without running
// `make install`. Don't use $MJIT_SEARCH_BUILD_DIR except for test-all.
struct stat st;
const char *hdr = dlsym(RTLD_DEFAULT, "MJIT_HEADER");
if (!hdr) {
verbose(1, "No MJIT_HEADER");
}
else if (hdr[0] != '/') {
verbose(1, "Non-absolute header file path: %s", hdr);
}
else if (stat(hdr, &st) || !S_ISREG(st.st_mode)) {
verbose(1, "Non-file header file path: %s", hdr);
}
else if ((st.st_uid != getuid()) || (st.st_mode & 022) ||
!rb_path_check(hdr)) {
verbose(1, "Unsafe header file: uid=%ld mode=%#o %s",
(long)st.st_uid, (unsigned)st.st_mode, hdr);
return FALSE;
}
else {
// Do not pass PRELOADENV to child processes, on
// multi-arch environment
verbose(3, "PRELOADENV("PRELOADENV")=%s", getenv(PRELOADENV));
// assume no other PRELOADENV in test-all
unsetenv(PRELOADENV);
verbose(3, "MJIT_HEADER: %s", hdr);
header_file = ruby_strdup(hdr);
if (!header_file) return false;
}
}
else
#endif
#ifndef _MSC_VER
{
// A name of the header file included in any C file generated by MJIT for iseqs.
static const char header_name[] = MJIT_HEADER_INSTALL_DIR "/" MJIT_MIN_HEADER_NAME;
const size_t header_name_len = sizeof(header_name) - 1;
header_file = xmalloc(baselen + header_name_len + 1);
p = append_str2(header_file, basedir, baselen);
p = append_str2(p, header_name, header_name_len + 1);
if ((fd = rb_cloexec_open(header_file, O_RDONLY, 0)) < 0) {
verbose(1, "Cannot access header file: %s", header_file);
xfree(header_file);
header_file = NULL;
return false;
}
(void)close(fd);
}
pch_file = get_uniq_filename(0, MJIT_TMP_PREFIX "h", ".h.gch");
#else
{
static const char pch_name[] = MJIT_HEADER_INSTALL_DIR "/" MJIT_PRECOMPILED_HEADER_NAME;
const size_t pch_name_len = sizeof(pch_name) - 1;
pch_file = xmalloc(baselen + pch_name_len + 1);
p = append_str2(pch_file, basedir, baselen);
p = append_str2(p, pch_name, pch_name_len + 1);
if ((fd = rb_cloexec_open(pch_file, O_RDONLY, 0)) < 0) {
verbose(1, "Cannot access precompiled header file: %s", pch_file);
xfree(pch_file);
pch_file = NULL;
return false;
}
(void)close(fd);
}
#endif
#ifdef _WIN32
basedir_val = ruby_archlibdir_path;
basedir = StringValuePtr(basedir_val);
baselen = RSTRING_LEN(basedir_val);
libruby_pathflag = p = xmalloc(libpathflag_len + baselen + 1);
p = append_str(p, libpathflag);
p = append_str2(p, basedir, baselen);
*p = '\0';
#endif
return true;
}
#ifdef _WIN32
UINT rb_w32_system_tmpdir(WCHAR *path, UINT len);
#endif
static char *
system_default_tmpdir(void)
{
// c.f. ext/etc/etc.c:etc_systmpdir()
#ifdef _WIN32
WCHAR tmppath[_MAX_PATH];
UINT len = rb_w32_system_tmpdir(tmppath, numberof(tmppath));
if (len) {
int blen = WideCharToMultiByte(CP_UTF8, 0, tmppath, len, NULL, 0, NULL, NULL);
char *tmpdir = xmalloc(blen + 1);
WideCharToMultiByte(CP_UTF8, 0, tmppath, len, tmpdir, blen, NULL, NULL);
tmpdir[blen] = '\0';
return tmpdir;
}
#elif defined _CS_DARWIN_USER_TEMP_DIR
char path[MAXPATHLEN];
size_t len = confstr(_CS_DARWIN_USER_TEMP_DIR, path, sizeof(path));
if (len > 0) {
char *tmpdir = xmalloc(len);
if (len > sizeof(path)) {
confstr(_CS_DARWIN_USER_TEMP_DIR, tmpdir, len);
}
else {
memcpy(tmpdir, path, len);
}
return tmpdir;
}
#endif
return 0;
}
static int
check_tmpdir(const char *dir)
{
struct stat st;
if (!dir) return FALSE;
if (stat(dir, &st)) return FALSE;
#ifndef S_ISDIR
# define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif
if (!S_ISDIR(st.st_mode)) return FALSE;
#ifndef _WIN32
# ifndef S_IWOTH
# define S_IWOTH 002
# endif
if (st.st_mode & S_IWOTH) {
# ifdef S_ISVTX
if (!(st.st_mode & S_ISVTX)) return FALSE;
# else
return FALSE;
# endif
}
if (access(dir, W_OK)) return FALSE;
#endif
return TRUE;
}
static char *
system_tmpdir(void)
{
char *tmpdir;
# define RETURN_ENV(name) \
if (check_tmpdir(tmpdir = getenv(name))) return ruby_strdup(tmpdir)
RETURN_ENV("TMPDIR");
RETURN_ENV("TMP");
tmpdir = system_default_tmpdir();
if (check_tmpdir(tmpdir)) return tmpdir;
return ruby_strdup("/tmp");
# undef RETURN_ENV
}
// Minimum value for JIT cache size.
#define MIN_CACHE_SIZE 10
// Default permitted number of units with a JIT code kept in memory.
#define DEFAULT_MAX_CACHE_SIZE 10000
// A default threshold used to add iseq to JIT.
#define DEFAULT_MIN_CALLS_TO_ADD 10000
// Start MJIT worker. Return TRUE if worker is successfully started.
static bool
start_worker(void)
{
stop_worker_p = false;
worker_stopped = false;
if (!rb_thread_create_mjit_thread(mjit_worker)) {
mjit_enabled = false;
rb_native_mutex_destroy(&mjit_engine_mutex);
rb_native_cond_destroy(&mjit_pch_wakeup);
rb_native_cond_destroy(&mjit_client_wakeup);
rb_native_cond_destroy(&mjit_worker_wakeup);
rb_native_cond_destroy(&mjit_gc_wakeup);
verbose(1, "Failure in MJIT thread initialization\n");
return false;
}
return true;
}
// There's no strndup on Windows
static char*
ruby_strndup(const char *str, size_t n)
{
char *ret = xmalloc(n + 1);
memcpy(ret, str, n);
ret[n] = '\0';
return ret;
}
// Convert "foo bar" to {"foo", "bar", NULL} array. Caller is responsible for
// freeing a returned buffer and its elements.
static char **
split_flags(const char *flags)
{
char *buf[MAXPATHLEN];
int i = 0;
char *next;
for (; flags != NULL; flags = next) {
next = strchr(flags, ' ');
if (next == NULL) {
if (strlen(flags) > 0)
buf[i++] = strdup(flags);
}
else {
if (next > flags)
buf[i++] = ruby_strndup(flags, next - flags);
next++; // skip space
}
}
char **ret = xmalloc(sizeof(char *) * (i + 1));
memcpy(ret, buf, sizeof(char *) * i);
ret[i] = NULL;
return ret;
}
#define opt_match_noarg(s, l, name) \
opt_match(s, l, name) && (*(s) ? (rb_warn("argument to --mjit-" name " is ignored"), 1) : 1)
#define opt_match_arg(s, l, name) \
opt_match(s, l, name) && (*(s) ? 1 : (rb_raise(rb_eRuntimeError, "--mjit-" name " needs an argument"), 0))
void
mjit_setup_options(const char *s, struct mjit_options *mjit_opt)
{
const size_t l = strlen(s);
if (l == 0) {
return;
}
else if (opt_match_noarg(s, l, "warnings")) {
mjit_opt->warnings = 1;
}
else if (opt_match(s, l, "debug")) {
if (*s)
mjit_opt->debug_flags = strdup(s + 1);
else
mjit_opt->debug = 1;
}
else if (opt_match_noarg(s, l, "wait")) {
mjit_opt->wait = 1;
}
else if (opt_match_noarg(s, l, "save-temps")) {
mjit_opt->save_temps = 1;
}
else if (opt_match(s, l, "verbose")) {
mjit_opt->verbose = *s ? atoi(s + 1) : 1;
}
else if (opt_match_arg(s, l, "max-cache")) {
mjit_opt->max_cache_size = atoi(s + 1);
}
else if (opt_match_arg(s, l, "min-calls")) {
mjit_opt->min_calls = atoi(s + 1);
}
else {
rb_raise(rb_eRuntimeError,
"invalid MJIT option `%s' (--help will show valid MJIT options)", s);
}
}
#define M(shortopt, longopt, desc) RUBY_OPT_MESSAGE(shortopt, longopt, desc)
const struct ruby_opt_message mjit_option_messages[] = {
M("--mjit-warnings", "", "Enable printing JIT warnings"),
M("--mjit-debug", "", "Enable JIT debugging (very slow), or add cflags if specified"),
M("--mjit-wait", "", "Wait until JIT compilation finishes every time (for testing)"),
M("--mjit-save-temps", "", "Save JIT temporary files in $TMP or /tmp (for testing)"),
M("--mjit-verbose=num", "", "Print JIT logs of level num or less to stderr (default: 0)"),
M("--mjit-max-cache=num", "", "Max number of methods to be JIT-ed in a cache (default: "
STRINGIZE(DEFAULT_MAX_CACHE_SIZE) ")"),
M("--mjit-min-calls=num", "", "Number of calls to trigger JIT (for testing, default: "
STRINGIZE(DEFAULT_MIN_CALLS_TO_ADD) ")"),
{0}
};
#undef M
// Initialize MJIT. Start a thread creating the precompiled header and
// processing ISeqs. The function should be called first for using MJIT.
// If everything is successful, MJIT_INIT_P will be TRUE.
void
mjit_init(const struct mjit_options *opts)
{
mjit_opts = *opts;
mjit_enabled = true;
mjit_call_p = true;
// Normalize options
if (mjit_opts.min_calls == 0)
mjit_opts.min_calls = DEFAULT_MIN_CALLS_TO_ADD;
if (mjit_opts.max_cache_size <= 0)
mjit_opts.max_cache_size = DEFAULT_MAX_CACHE_SIZE;
if (mjit_opts.max_cache_size < MIN_CACHE_SIZE)
mjit_opts.max_cache_size = MIN_CACHE_SIZE;
// Initialize variables for compilation
#ifdef _MSC_VER
pch_status = PCH_SUCCESS; // has prebuilt precompiled header
#else
pch_status = PCH_NOT_READY;
#endif
cc_path = CC_COMMON_ARGS[0];
verbose(2, "MJIT: CC defaults to %s", cc_path);
cc_common_args = xmalloc(sizeof(CC_COMMON_ARGS));
memcpy((void *)cc_common_args, CC_COMMON_ARGS, sizeof(CC_COMMON_ARGS));
cc_added_args = split_flags(opts->debug_flags);
xfree(opts->debug_flags);
#if MJIT_CFLAGS_PIPE
// eliminate a flag incompatible with `-pipe`
for (size_t i = 0, j = 0; i < sizeof(CC_COMMON_ARGS) / sizeof(char *); i++) {
if (CC_COMMON_ARGS[i] && strncmp("-save-temps", CC_COMMON_ARGS[i], strlen("-save-temps")) == 0)
continue; // skip -save-temps flag
cc_common_args[j] = CC_COMMON_ARGS[i];
j++;
}
#endif
tmp_dir = system_tmpdir();
verbose(2, "MJIT: tmp_dir is %s", tmp_dir);
if (!init_header_filename()) {
mjit_enabled = false;
verbose(1, "Failure in MJIT header file name initialization\n");
return;
}
pch_owner_pid = getpid();
// Initialize mutex
rb_native_mutex_initialize(&mjit_engine_mutex);
rb_native_cond_initialize(&mjit_pch_wakeup);
rb_native_cond_initialize(&mjit_client_wakeup);
rb_native_cond_initialize(&mjit_worker_wakeup);
rb_native_cond_initialize(&mjit_gc_wakeup);
// Make sure the saved_ec of the initial thread's root_fiber is scanned by mark_ec_units.
//
// rb_threadptr_root_fiber_setup for the initial thread is called before mjit_init,
// meaning mjit_cont_new is skipped for the root_fiber. Therefore we need to call
// rb_fiber_init_mjit_cont again with mjit_enabled=true to set the root_fiber's mjit_cont.
rb_fiber_init_mjit_cont(GET_EC()->fiber_ptr);
// Initialize worker thread
start_worker();
}
static void
stop_worker(void)
{
rb_execution_context_t *ec = GET_EC();
while (!worker_stopped) {
verbose(3, "Sending cancel signal to worker");
CRITICAL_SECTION_START(3, "in stop_worker");
stop_worker_p = true; // Setting this inside loop because RUBY_VM_CHECK_INTS may make this false.
rb_native_cond_broadcast(&mjit_worker_wakeup);
CRITICAL_SECTION_FINISH(3, "in stop_worker");
RUBY_VM_CHECK_INTS(ec);
}
}
// Stop JIT-compiling methods but compiled code is kept available.
VALUE
mjit_pause(bool wait_p)
{
if (!mjit_enabled) {
rb_raise(rb_eRuntimeError, "MJIT is not enabled");
}
if (worker_stopped) {
return Qfalse;
}
// Flush all queued units with no option or `wait: true`
if (wait_p) {
struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 1000;
while (unit_queue.length > 0 && active_units.length < mjit_opts.max_cache_size) { // inverse of condition that waits for mjit_worker_wakeup
CRITICAL_SECTION_START(3, "in mjit_pause for a worker wakeup");
rb_native_cond_broadcast(&mjit_worker_wakeup);
CRITICAL_SECTION_FINISH(3, "in mjit_pause for a worker wakeup");
rb_thread_wait_for(tv);
}
}
stop_worker();
return Qtrue;
}
// Restart JIT-compiling methods after mjit_pause.
VALUE
mjit_resume(void)
{
if (!mjit_enabled) {
rb_raise(rb_eRuntimeError, "MJIT is not enabled");
}
if (!worker_stopped) {
return Qfalse;
}
if (!start_worker()) {
rb_raise(rb_eRuntimeError, "Failed to resume MJIT worker");
}
return Qtrue;
}
// Skip calling `clean_temp_files` for units which currently exist in the list.
static void
skip_cleaning_object_files(struct rb_mjit_unit_list *list)
{
struct rb_mjit_unit *unit = NULL, *next;
// No mutex for list, assuming MJIT worker does not exist yet since it's immediately after fork.
ccan_list_for_each_safe(&list->head, unit, next, unode) {
#if defined(_WIN32) // mswin doesn't reach here either. This is for MinGW.
if (unit->so_file) unit->so_file = NULL;
#endif
}
}
// This is called after fork initiated by Ruby's method to launch MJIT worker thread
// for child Ruby process.
//
// In multi-process Ruby applications, child Ruby processes do most of the jobs.
// Thus we want child Ruby processes to enqueue ISeqs to MJIT worker's queue and
// call the JIT-ed code.
//
// But unfortunately current MJIT-generated code is process-specific. After the fork,
// JIT-ed code created by parent Ruby process cannot be used in child Ruby process
// because the code could rely on inline cache values (ivar's IC, send's CC) which
// may vary between processes after fork or embed some process-specific addresses.
//
// So child Ruby process can't request parent process to JIT an ISeq and use the code.
// Instead of that, MJIT worker thread is created for all child Ruby processes, even
// while child processes would end up with compiling the same ISeqs.
void
mjit_child_after_fork(void)
{
if (!mjit_enabled)
return;
/* Let parent process delete the already-compiled object files.
This must be done before starting MJIT worker on child process. */
skip_cleaning_object_files(&active_units);
/* MJIT worker thread is not inherited on fork. Start it for this child process. */
start_worker();
}
// Edit 0 to 1 to enable this feature for investigating hot methods
#define MJIT_COUNTER 0
#if MJIT_COUNTER
static void
mjit_dump_total_calls(void)
{
struct rb_mjit_unit *unit;
fprintf(stderr, "[MJIT_COUNTER] total_calls of active_units:\n");
ccan_list_for_each(&active_units.head, unit, unode) {
const rb_iseq_t *iseq = unit->iseq;
fprintf(stderr, "%8ld: %s@%s:%d\n", ISEQ_BODY(iseq)->total_calls, RSTRING_PTR(ISEQ_BODY(iseq)->location.label),
RSTRING_PTR(rb_iseq_path(iseq)), FIX2INT(ISEQ_BODY(iseq)->location.first_lineno));
}
}
#endif
// Finish the threads processing units and creating PCH, finalize
// and free MJIT data. It should be called last during MJIT
// life.
//
// If close_handle_p is true, it calls dlclose() for JIT-ed code. So it should be false
// if the code can still be on stack. ...But it means to leak JIT-ed handle forever (FIXME).
void
mjit_finish(bool close_handle_p)
{
if (!mjit_enabled)
return;
// Wait for pch finish
verbose(2, "Stopping worker thread");
CRITICAL_SECTION_START(3, "in mjit_finish to wakeup from pch");
// As our threads are detached, we could just cancel them. But it
// is a bad idea because OS processes (C compiler) started by
// threads can produce temp files. And even if the temp files are
// removed, the used C compiler still complaint about their
// absence. So wait for a clean finish of the threads.
while (pch_status == PCH_NOT_READY) {
verbose(3, "Waiting wakeup from make_pch");
rb_native_cond_wait(&mjit_pch_wakeup, &mjit_engine_mutex);
}
CRITICAL_SECTION_FINISH(3, "in mjit_finish to wakeup from pch");
// Stop worker
stop_worker();
rb_native_mutex_destroy(&mjit_engine_mutex);
rb_native_cond_destroy(&mjit_pch_wakeup);
rb_native_cond_destroy(&mjit_client_wakeup);
rb_native_cond_destroy(&mjit_worker_wakeup);
rb_native_cond_destroy(&mjit_gc_wakeup);
#if MJIT_COUNTER
mjit_dump_total_calls();
#endif
#ifndef _MSC_VER // mswin has prebuilt precompiled header
if (!mjit_opts.save_temps && getpid() == pch_owner_pid)
remove_file(pch_file);
xfree(header_file); header_file = NULL;
#endif
xfree((void *)cc_common_args); cc_common_args = NULL;
for (char **flag = cc_added_args; *flag != NULL; flag++)
xfree(*flag);
xfree((void *)cc_added_args); cc_added_args = NULL;
xfree(tmp_dir); tmp_dir = NULL;
xfree(pch_file); pch_file = NULL;
mjit_call_p = false;
free_list(&unit_queue, close_handle_p);
free_list(&active_units, close_handle_p);
free_list(&compact_units, close_handle_p);
free_list(&stale_units, close_handle_p);
finish_conts();
mjit_enabled = false;
verbose(1, "Successful MJIT finish");
}
// Called by rb_vm_mark().
//
// Mark an ISeq being compiled to prevent its CCs from being GC-ed, which
// an MJIT worker may concurrently see.
//
// Also mark active_units so that we do not GC ISeq which may still be
// referred to by mjit_recompile() or compact_all_jit_code().
void
mjit_mark(void)
{
if (!mjit_enabled)
return;
RUBY_MARK_ENTER("mjit");
// We need to release a lock when calling rb_gc_mark to avoid doubly acquiring
// a lock by by mjit_gc_start_hook inside rb_gc_mark.
//
// Because an MJIT worker may modify active_units anytime, we need to convert
// the linked list to an array to safely loop its ISeqs without keeping a lock.
CRITICAL_SECTION_START(4, "mjit_mark");
int length = 0;
if (compiling_iseqs != NULL) {
while (compiling_iseqs[length]) length++;
}
length += active_units.length;
const rb_iseq_t **iseqs = ALLOCA_N(const rb_iseq_t *, length);
struct rb_mjit_unit *unit = NULL;
int i = 0;
if (compiling_iseqs != NULL) {
while (compiling_iseqs[i]) {
iseqs[i] = compiling_iseqs[i];
i++;
}
}
ccan_list_for_each(&active_units.head, unit, unode) {
iseqs[i] = unit->iseq;
i++;
}
assert(i == length);
CRITICAL_SECTION_FINISH(4, "mjit_mark");
for (i = 0; i < length; i++) {
if (iseqs[i] == NULL) // ISeq is GC-ed
continue;
rb_gc_mark((VALUE)iseqs[i]);
}
RUBY_MARK_LEAVE("mjit");
}
// Called by rb_iseq_mark() to mark cc_entries captured for MJIT
void
mjit_mark_cc_entries(const struct rb_iseq_constant_body *const body)
{
const struct rb_callcache **cc_entries;
if (body->jit_unit && (cc_entries = body->jit_unit->cc_entries) != NULL) {
// It must be `body->jit_unit->cc_entries_size` instead of `body->ci_size` to mark children's cc_entries
for (unsigned int i = 0; i < body->jit_unit->cc_entries_size; i++) {
const struct rb_callcache *cc = cc_entries[i];
if (cc != NULL && vm_cc_markable(cc)) {
// Pin `cc` and `cc->cme` against GC.compact as their addresses may be written in JIT-ed code.
rb_gc_mark((VALUE)cc);
rb_gc_mark((VALUE)vm_cc_cme(cc));
}
}
}
}
#endif // USE_MJIT
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