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ruby--ruby/vm_callinfo.h
Jemma Issroff 913979bede
Make inline cache reads / writes atomic with object shapes
Prior to this commit, we were reading and writing ivar index and
shape ID in inline caches in two separate instructions when
getting and setting ivars. This meant there was a race condition
with ractors and these caches where one ractor could change
a value in the cache while another was still reading from it.

This commit instead reads and writes shape ID and ivar index to
inline caches atomically so there is no longer a race condition.

Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
Co-Authored-By: John Hawthorn <john@hawthorn.email>
2022-10-11 08:40:56 -07:00

545 lines
16 KiB
C

#ifndef RUBY_VM_CALLINFO_H /*-*-C-*-vi:se ft=c:*/
#define RUBY_VM_CALLINFO_H
/**
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
*/
#include "debug_counter.h"
#include "internal/class.h"
#include "shape.h"
enum vm_call_flag_bits {
VM_CALL_ARGS_SPLAT_bit, /* m(*args) */
VM_CALL_ARGS_BLOCKARG_bit, /* m(&block) */
VM_CALL_FCALL_bit, /* m(...) */
VM_CALL_VCALL_bit, /* m */
VM_CALL_ARGS_SIMPLE_bit, /* (ci->flag & (SPLAT|BLOCKARG)) && blockiseq == NULL && ci->kw_arg == NULL */
VM_CALL_BLOCKISEQ_bit, /* has blockiseq */
VM_CALL_KWARG_bit, /* has kwarg */
VM_CALL_KW_SPLAT_bit, /* m(**opts) */
VM_CALL_TAILCALL_bit, /* located at tail position */
VM_CALL_SUPER_bit, /* super */
VM_CALL_ZSUPER_bit, /* zsuper */
VM_CALL_OPT_SEND_bit, /* internal flag */
VM_CALL_KW_SPLAT_MUT_bit, /* kw splat hash can be modified (to avoid allocating a new one) */
VM_CALL__END
};
#define VM_CALL_ARGS_SPLAT (0x01 << VM_CALL_ARGS_SPLAT_bit)
#define VM_CALL_ARGS_BLOCKARG (0x01 << VM_CALL_ARGS_BLOCKARG_bit)
#define VM_CALL_FCALL (0x01 << VM_CALL_FCALL_bit)
#define VM_CALL_VCALL (0x01 << VM_CALL_VCALL_bit)
#define VM_CALL_ARGS_SIMPLE (0x01 << VM_CALL_ARGS_SIMPLE_bit)
#define VM_CALL_BLOCKISEQ (0x01 << VM_CALL_BLOCKISEQ_bit)
#define VM_CALL_KWARG (0x01 << VM_CALL_KWARG_bit)
#define VM_CALL_KW_SPLAT (0x01 << VM_CALL_KW_SPLAT_bit)
#define VM_CALL_TAILCALL (0x01 << VM_CALL_TAILCALL_bit)
#define VM_CALL_SUPER (0x01 << VM_CALL_SUPER_bit)
#define VM_CALL_ZSUPER (0x01 << VM_CALL_ZSUPER_bit)
#define VM_CALL_OPT_SEND (0x01 << VM_CALL_OPT_SEND_bit)
#define VM_CALL_KW_SPLAT_MUT (0x01 << VM_CALL_KW_SPLAT_MUT_bit)
struct rb_callinfo_kwarg {
int keyword_len;
VALUE keywords[];
};
static inline size_t
rb_callinfo_kwarg_bytes(int keyword_len)
{
return rb_size_mul_add_or_raise(
keyword_len,
sizeof(VALUE),
sizeof(struct rb_callinfo_kwarg),
rb_eRuntimeError);
}
// imemo_callinfo
struct rb_callinfo {
VALUE flags;
const struct rb_callinfo_kwarg *kwarg;
VALUE mid;
VALUE flag;
VALUE argc;
};
#ifndef USE_EMBED_CI
#define USE_EMBED_CI 1
#endif
#if SIZEOF_VALUE == 8
#define CI_EMBED_TAG_bits 1
#define CI_EMBED_ARGC_bits 15
#define CI_EMBED_FLAG_bits 16
#define CI_EMBED_ID_bits 32
#elif SIZEOF_VALUE == 4
#define CI_EMBED_TAG_bits 1
#define CI_EMBED_ARGC_bits 3
#define CI_EMBED_FLAG_bits 13
#define CI_EMBED_ID_bits 15
#endif
#if (CI_EMBED_TAG_bits + CI_EMBED_ARGC_bits + CI_EMBED_FLAG_bits + CI_EMBED_ID_bits) != (SIZEOF_VALUE * 8)
#error
#endif
#define CI_EMBED_FLAG 0x01
#define CI_EMBED_ARGC_SHFT (CI_EMBED_TAG_bits)
#define CI_EMBED_ARGC_MASK ((((VALUE)1)<<CI_EMBED_ARGC_bits) - 1)
#define CI_EMBED_FLAG_SHFT (CI_EMBED_TAG_bits + CI_EMBED_ARGC_bits)
#define CI_EMBED_FLAG_MASK ((((VALUE)1)<<CI_EMBED_FLAG_bits) - 1)
#define CI_EMBED_ID_SHFT (CI_EMBED_TAG_bits + CI_EMBED_ARGC_bits + CI_EMBED_FLAG_bits)
#define CI_EMBED_ID_MASK ((((VALUE)1)<<CI_EMBED_ID_bits) - 1)
static inline bool
vm_ci_packed_p(const struct rb_callinfo *ci)
{
#if USE_EMBED_CI
if (LIKELY(((VALUE)ci) & 0x01)) {
return 1;
}
else {
VM_ASSERT(IMEMO_TYPE_P(ci, imemo_callinfo));
return 0;
}
#else
return 0;
#endif
}
static inline bool
vm_ci_p(const struct rb_callinfo *ci)
{
if (vm_ci_packed_p(ci) || IMEMO_TYPE_P(ci, imemo_callinfo)) {
return 1;
}
else {
return 0;
}
}
static inline ID
vm_ci_mid(const struct rb_callinfo *ci)
{
if (vm_ci_packed_p(ci)) {
return (((VALUE)ci) >> CI_EMBED_ID_SHFT) & CI_EMBED_ID_MASK;
}
else {
return (ID)ci->mid;
}
}
static inline unsigned int
vm_ci_flag(const struct rb_callinfo *ci)
{
if (vm_ci_packed_p(ci)) {
return (unsigned int)((((VALUE)ci) >> CI_EMBED_FLAG_SHFT) & CI_EMBED_FLAG_MASK);
}
else {
return (unsigned int)ci->flag;
}
}
static inline unsigned int
vm_ci_argc(const struct rb_callinfo *ci)
{
if (vm_ci_packed_p(ci)) {
return (unsigned int)((((VALUE)ci) >> CI_EMBED_ARGC_SHFT) & CI_EMBED_ARGC_MASK);
}
else {
return (unsigned int)ci->argc;
}
}
static inline const struct rb_callinfo_kwarg *
vm_ci_kwarg(const struct rb_callinfo *ci)
{
if (vm_ci_packed_p(ci)) {
return NULL;
}
else {
return ci->kwarg;
}
}
static inline void
vm_ci_dump(const struct rb_callinfo *ci)
{
if (vm_ci_packed_p(ci)) {
ruby_debug_printf("packed_ci ID:%s flag:%x argc:%u\n",
rb_id2name(vm_ci_mid(ci)), vm_ci_flag(ci), vm_ci_argc(ci));
}
else {
rp(ci);
}
}
#define vm_ci_new(mid, flag, argc, kwarg) vm_ci_new_(mid, flag, argc, kwarg, __FILE__, __LINE__)
#define vm_ci_new_runtime(mid, flag, argc, kwarg) vm_ci_new_runtime_(mid, flag, argc, kwarg, __FILE__, __LINE__)
/* This is passed to STATIC_ASSERT. Cannot be an inline function. */
#define VM_CI_EMBEDDABLE_P(mid, flag, argc, kwarg) \
(((mid ) & ~CI_EMBED_ID_MASK) ? false : \
((flag) & ~CI_EMBED_FLAG_MASK) ? false : \
((argc) & ~CI_EMBED_ARGC_MASK) ? false : \
(kwarg) ? false : true)
#define vm_ci_new_id(mid, flag, argc, must_zero) \
((const struct rb_callinfo *) \
((((VALUE)(mid )) << CI_EMBED_ID_SHFT) | \
(((VALUE)(flag)) << CI_EMBED_FLAG_SHFT) | \
(((VALUE)(argc)) << CI_EMBED_ARGC_SHFT) | \
RUBY_FIXNUM_FLAG))
static inline const struct rb_callinfo *
vm_ci_new_(ID mid, unsigned int flag, unsigned int argc, const struct rb_callinfo_kwarg *kwarg, const char *file, int line)
{
#if USE_EMBED_CI
if (VM_CI_EMBEDDABLE_P(mid, flag, argc, kwarg)) {
RB_DEBUG_COUNTER_INC(ci_packed);
return vm_ci_new_id(mid, flag, argc, kwarg);
}
#endif
const bool debug = 0;
if (debug) ruby_debug_printf("%s:%d ", file, line);
// TODO: dedup
const struct rb_callinfo *ci = (const struct rb_callinfo *)
rb_imemo_new(imemo_callinfo,
(VALUE)mid,
(VALUE)flag,
(VALUE)argc,
(VALUE)kwarg);
if (debug) rp(ci);
if (kwarg) {
RB_DEBUG_COUNTER_INC(ci_kw);
}
else {
RB_DEBUG_COUNTER_INC(ci_nokw);
}
VM_ASSERT(vm_ci_flag(ci) == flag);
VM_ASSERT(vm_ci_argc(ci) == argc);
return ci;
}
static inline const struct rb_callinfo *
vm_ci_new_runtime_(ID mid, unsigned int flag, unsigned int argc, const struct rb_callinfo_kwarg *kwarg, const char *file, int line)
{
RB_DEBUG_COUNTER_INC(ci_runtime);
return vm_ci_new_(mid, flag, argc, kwarg, file, line);
}
#define VM_CALLINFO_NOT_UNDER_GC IMEMO_FL_USER0
static inline bool
vm_ci_markable(const struct rb_callinfo *ci)
{
if (! ci) {
return false; /* or true? This is Qfalse... */
}
else if (vm_ci_packed_p(ci)) {
return true;
}
else {
VM_ASSERT(IMEMO_TYPE_P(ci, imemo_callinfo));
return ! FL_ANY_RAW((VALUE)ci, VM_CALLINFO_NOT_UNDER_GC);
}
}
#define VM_CI_ON_STACK(mid_, flags_, argc_, kwarg_) \
(struct rb_callinfo) { \
.flags = T_IMEMO | \
(imemo_callinfo << FL_USHIFT) | \
VM_CALLINFO_NOT_UNDER_GC, \
.mid = mid_, \
.flag = flags_, \
.argc = argc_, \
.kwarg = kwarg_, \
}
typedef VALUE (*vm_call_handler)(
struct rb_execution_context_struct *ec,
struct rb_control_frame_struct *cfp,
struct rb_calling_info *calling);
// imemo_callcache
struct rb_callcache {
const VALUE flags;
/* inline cache: key */
const VALUE klass; // should not mark it because klass can not be free'd
// because of this marking. When klass is collected,
// cc will be cleared (cc->klass = 0) at vm_ccs_free().
/* inline cache: values */
const struct rb_callable_method_entry_struct * const cme_;
const vm_call_handler call_;
union {
struct {
uintptr_t value; // Shape ID in upper bits, index in lower bits
} attr;
const enum method_missing_reason method_missing_reason; /* used by method_missing */
VALUE v;
} aux_;
};
#define VM_CALLCACHE_UNMARKABLE FL_FREEZE
#define VM_CALLCACHE_ON_STACK FL_EXIVAR
extern const struct rb_callcache *rb_vm_empty_cc(void);
extern const struct rb_callcache *rb_vm_empty_cc_for_super(void);
#define vm_cc_empty() rb_vm_empty_cc()
static inline void
vm_cc_attr_index_initialize(const struct rb_callcache *cc, shape_id_t shape_id)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc != vm_cc_empty());
*(uintptr_t *)&cc->aux_.attr.value = (uintptr_t)(shape_id) << SHAPE_FLAG_SHIFT;
}
static inline const struct rb_callcache *
vm_cc_new(VALUE klass,
const struct rb_callable_method_entry_struct *cme,
vm_call_handler call)
{
const struct rb_callcache *cc = (const struct rb_callcache *)rb_imemo_new(imemo_callcache, (VALUE)cme, (VALUE)call, 0, klass);
vm_cc_attr_index_initialize(cc, INVALID_SHAPE_ID);
RB_DEBUG_COUNTER_INC(cc_new);
return cc;
}
#define VM_CC_ON_STACK(clazz, call, aux, cme) \
(struct rb_callcache) { \
.flags = T_IMEMO | \
(imemo_callcache << FL_USHIFT) | \
VM_CALLCACHE_UNMARKABLE | \
VM_CALLCACHE_ON_STACK, \
.klass = clazz, \
.cme_ = cme, \
.call_ = call, \
.aux_ = aux, \
}
static inline bool
vm_cc_class_check(const struct rb_callcache *cc, VALUE klass)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc->klass == 0 ||
RB_TYPE_P(cc->klass, T_CLASS) || RB_TYPE_P(cc->klass, T_ICLASS));
return cc->klass == klass;
}
static inline int
vm_cc_markable(const struct rb_callcache *cc)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
return FL_TEST_RAW((VALUE)cc, VM_CALLCACHE_UNMARKABLE) == 0;
}
static inline const struct rb_callable_method_entry_struct *
vm_cc_cme(const struct rb_callcache *cc)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc->call_ == NULL || // not initialized yet
!vm_cc_markable(cc) ||
cc->cme_ != NULL);
return cc->cme_;
}
static inline vm_call_handler
vm_cc_call(const struct rb_callcache *cc)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc->call_ != NULL);
return cc->call_;
}
static inline attr_index_t
vm_cc_attr_index(const struct rb_callcache *cc)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
return (attr_index_t)((cc->aux_.attr.value & SHAPE_FLAG_MASK) - 1);
}
static inline shape_id_t
vm_cc_attr_index_dest_shape_id(const struct rb_callcache *cc)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
return cc->aux_.attr.value >> SHAPE_FLAG_SHIFT;
}
static inline void
vm_cc_atomic_shape_and_index(const struct rb_callcache *cc, shape_id_t * shape_id, attr_index_t * index)
{
uintptr_t cache_value = cc->aux_.attr.value; // Atomically read 64 bits
*shape_id = (shape_id_t)(cache_value >> SHAPE_FLAG_SHIFT);
*index = (attr_index_t)(cache_value & SHAPE_FLAG_MASK) - 1;
return;
}
static inline void
vm_ic_atomic_shape_and_index(const struct iseq_inline_iv_cache_entry *ic, shape_id_t * shape_id, attr_index_t * index)
{
uintptr_t cache_value = ic->value; // Atomically read 64 bits
*shape_id = (shape_id_t)(cache_value >> SHAPE_FLAG_SHIFT);
*index = (attr_index_t)(cache_value & SHAPE_FLAG_MASK) - 1;
return;
}
static inline shape_id_t
vm_ic_attr_index_dest_shape_id(const struct iseq_inline_iv_cache_entry *ic)
{
return (shape_id_t)(ic->value >> SHAPE_FLAG_SHIFT);
}
static inline unsigned int
vm_cc_cmethod_missing_reason(const struct rb_callcache *cc)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
return cc->aux_.method_missing_reason;
}
static inline bool
vm_cc_invalidated_p(const struct rb_callcache *cc)
{
if (cc->klass && !METHOD_ENTRY_INVALIDATED(vm_cc_cme(cc))) {
return false;
}
else {
return true;
}
}
// For MJIT. cc_cme is supposed to have inlined `vm_cc_cme(cc)`.
static inline bool
vm_cc_valid_p(const struct rb_callcache *cc, const rb_callable_method_entry_t *cc_cme, VALUE klass)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
if (cc->klass == klass && !METHOD_ENTRY_INVALIDATED(cc_cme)) {
return 1;
}
else {
return 0;
}
}
/* callcache: mutate */
static inline void
vm_cc_call_set(const struct rb_callcache *cc, vm_call_handler call)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc != vm_cc_empty());
*(vm_call_handler *)&cc->call_ = call;
}
static inline void
vm_cc_attr_index_set(const struct rb_callcache *cc, attr_index_t index, shape_id_t dest_shape_id)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc != vm_cc_empty());
*(uintptr_t *)&cc->aux_.attr.value = (index + 1) | ((uintptr_t)(dest_shape_id) << SHAPE_FLAG_SHIFT);
}
static inline void
vm_ic_attr_index_set(const rb_iseq_t *iseq, const struct iseq_inline_iv_cache_entry *ic, attr_index_t index, shape_id_t dest_shape_id)
{
*(uintptr_t *)&ic->value = ((uintptr_t)dest_shape_id << SHAPE_FLAG_SHIFT) | (index + 1);
}
static inline void
vm_ic_attr_index_initialize(const struct iseq_inline_iv_cache_entry *ic, shape_id_t shape_id)
{
*(uintptr_t *)&ic->value = (uintptr_t)shape_id << SHAPE_FLAG_SHIFT;
}
static inline void
vm_cc_method_missing_reason_set(const struct rb_callcache *cc, enum method_missing_reason reason)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc != vm_cc_empty());
*(enum method_missing_reason *)&cc->aux_.method_missing_reason = reason;
}
static inline void
vm_cc_invalidate(const struct rb_callcache *cc)
{
VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache));
VM_ASSERT(cc != vm_cc_empty());
VM_ASSERT(cc->klass != 0); // should be enable
*(VALUE *)&cc->klass = 0;
RB_DEBUG_COUNTER_INC(cc_ent_invalidate);
}
/* calldata */
struct rb_call_data {
const struct rb_callinfo *ci;
const struct rb_callcache *cc;
};
struct rb_class_cc_entries {
#if VM_CHECK_MODE > 0
VALUE debug_sig;
#endif
int capa;
int len;
const struct rb_callable_method_entry_struct *cme;
struct rb_class_cc_entries_entry {
const struct rb_callinfo *ci;
const struct rb_callcache *cc;
} *entries;
};
#if VM_CHECK_MODE > 0
const rb_callable_method_entry_t *rb_vm_lookup_overloaded_cme(const rb_callable_method_entry_t *cme);
void rb_vm_dump_overloaded_cme_table(void);
static inline bool
vm_ccs_p(const struct rb_class_cc_entries *ccs)
{
return ccs->debug_sig == ~(VALUE)ccs;
}
static inline bool
vm_cc_check_cme(const struct rb_callcache *cc, const rb_callable_method_entry_t *cme)
{
if (vm_cc_cme(cc) == cme ||
(cme->def->iseq_overload && vm_cc_cme(cc) == rb_vm_lookup_overloaded_cme(cme))) {
return true;
}
else {
#if 1
// debug print
fprintf(stderr, "iseq_overload:%d\n", (int)cme->def->iseq_overload);
rp(cme);
rp(vm_cc_cme(cc));
rb_vm_lookup_overloaded_cme(cme);
#endif
return false;
}
}
#endif
// gc.c
void rb_vm_ccs_free(struct rb_class_cc_entries *ccs);
#endif /* RUBY_VM_CALLINFO_H */