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ruby--ruby/mjit_worker.c
Alan Wu e6f4a39a4d MJIT MSVC: Use /Z7 to avoid PDB write race 
With MSVC, MJIT uses the /Fd option on an installed PDB file when
compiling. Combined with the /Zi option, this causes the PDB file to be
modified every time MJIT compiles. Concurrent modifications to the same
PDB file is known to cause problems. MSVC even has an option, /FS to
deal with it. When running MJIT tests in parallel, sometimes this leads
to corrupting the PDB file, breaking subsequent compilations. On CI,
we get messages like these:

    rb_mjit_header-3.1.0.pdb is not the pdb file that was used when this precompiled header was created, recreate the precompiled header.

To avoid this race, use the /Z7 option when building precompiled header,
which asks the compiler to put debug info into the .obj file,
eliminating the need for pointing the compiler to the PDB file for the
precompiled header.

The /Fd option is changed to use a unique path based on the name of the
dll output. Because of the /debug linker flag, we generate a PDB file
at runtime even though we use /Z7.

There are a couple things missing from this change:
 - Because MJIT uses the interpreter's CFLAGS build option and that
   contains /Zi, putting /Z7 at the end leads to a build warning
 - With /Z7 no PDB file is built anymore, so the code for installing
   the PDB file can be removed

There might also be other problems with this change I haven't noticed
while developing this change using Github Actions. I don't have a
Windows dev environment with Visual Studio so I can't finish this
change easily. Please feel free to complete this change if it makes
sense.

Note:
 - On master, you can see the PDB file changing with llvm-pdbutil or a
   simple checksum. There is an age field in the file that is bumped
 - I'm not sure if users can specify compile flags on MSVC. If they
   couldn't, maybe it's easier to change MJIT's compile options to
   use /Z7 when building the precompile header.
 - MJIT could pass different options at runtime to generate fewer
   files. Right now it inherits the /DEBUG linker flag which causes
   a PDB file to be generated at runtime even though /Z7 is used.

Relevant MSVC docs:
 - [/Zi,/Z7](https://docs.microsoft.com/en-us/cpp/build/reference/z7-zi-zi-debug-information-format?view=msvc-160)
 - [/DEBUG](https://docs.microsoft.com/en-us/cpp/build/reference/debug-generate-debug-info?view=msvc-160)
 - [/FS](https://docs.microsoft.com/en-us/cpp/build/reference/fs-force-synchronous-pdb-writes?view=msvc-160)
2021-11-24 23:45:57 +09:00

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/**********************************************************************
mjit_worker.c - Worker for MRI method JIT compiler
Copyright (C) 2017 Vladimir Makarov <vmakarov@redhat.com>.
**********************************************************************/
// 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"
#include "builtin.h"
#include "insns.inc"
#include "insns_info.inc"
#include "internal/compile.h"
#ifdef _WIN32
#include <winsock2.h>
#include <windows.h>
#else
#include <sys/wait.h>
#include <sys/time.h>
#include <dlfcn.h>
#endif
#include <errno.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_PARAM_H
# include <sys/param.h>
#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 = true;
// Path of "/tmp", which can be changed to $TMP in MinGW.
static char *tmp_dir;
// 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 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 rb_iseq_t **compiling_iseqs = NULL;
static bool
set_compiling_iseqs(const rb_iseq_t *iseq)
{
compiling_iseqs = calloc(iseq->body->iseq_size + 2, sizeof(rb_iseq_t *)); // 2: 1 (unit->iseq) + 1 (NULL end)
if (compiling_iseqs == NULL)
return false;
compiling_iseqs[0] = iseq;
int i = 1;
unsigned int pos = 0;
while (pos < iseq->body->iseq_size) {
int insn = rb_vm_insn_decode(iseq->body->iseq_encoded[pos]);
if (insn == BIN(opt_send_without_block) || insn == BIN(opt_size)) {
CALL_DATA cd = (CALL_DATA)iseq->body->iseq_encoded[pos + 1];
extern const rb_iseq_t *rb_mjit_inlinable_iseq(const struct rb_callinfo *ci, const struct rb_callcache *cc);
const rb_iseq_t *iseq = rb_mjit_inlinable_iseq(cd->ci, cd->cc);
if (iseq != NULL) {
compiling_iseqs[i] = iseq;
i++;
}
}
pos += insn_len(insn);
}
return true;
}
static void
free_compiling_iseqs(void)
{
RBIMPL_WARNING_PUSH();
#ifdef _MSC_VER
RBIMPL_WARNING_IGNORED(4090); /* suppress false warning by MSVC */
#endif
free(compiling_iseqs);
RBIMPL_WARNING_POP();
compiling_iseqs = NULL;
}
bool
rb_mjit_compiling_iseq_p(const rb_iseq_t *iseq)
{
assert(compiling_iseqs != NULL);
int i = 0;
while (compiling_iseqs[i]) {
if (compiling_iseqs[i] == iseq) return true;
i++;
}
return false;
}
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, 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"
// Generate .pdb file in temporary directory instead of cwd.
files[5] = p = alloca(sizeof(char) * (rb_strlen_lit("-Fd") + strlen(so_file) - rb_strlen_lit(DLEXT) + rb_strlen_lit(".pdb") + 1));
p = append_lit(p, "-Fd");
p = append_str2(p, so_file, strlen(so_file) - rb_strlen_lit(DLEXT));
p = append_lit(p, ".pdb");
*p = '\0';
// files[6] = "-Z7"
// Put this last to override any debug options that came previously.
files[6] = p = alloca(sizeof(char) * rb_strlen_lit("-Z7") + 1);
p = append_lit(p, "-Z7");
*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",
"-c",
# 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) {
CRITICAL_SECTION_START(3, "before set_compiling_iseqs");
success &= set_compiling_iseqs(child_unit->iseq);
CRITICAL_SECTION_FINISH(3, "after set_compiling_iseqs");
if (!success) continue;
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);
CRITICAL_SECTION_START(3, "before compiling_iseqs free");
free_compiling_iseqs();
CRITICAL_SECTION_FINISH(3, "after compiling_iseqs free");
}
// 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_COMPILED_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);
if (in_jit)
in_jit &= set_compiling_iseqs(unit->iseq);
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");
free_compiling_iseqs();
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;
}
}
static void mjit_add_iseq_to_process(const rb_iseq_t *iseq, const struct rb_mjit_compile_info *compile_info, bool worker_p);
// 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 / 100` times (default: 100) of compaction.
// Note: GC of compacted code has not been implemented yet.
int max_compact_size = mjit_opts.max_cache_size / 100;
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 ((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);
// Lazily put it to unit_queue as well to avoid race conditions on jit_unit with mjit_compile.
mjit_add_iseq_to_process(unit->iseq, &unit->iseq->body->jit_unit->compile_info, true);
}
}
}
// 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;
}
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