/**********************************************************************

  mjit_compiler.c - MRI method JIT compiler

  Copyright (C) 2017 Takashi Kokubun <takashikkbn@gmail.com>.

**********************************************************************/

#include "ruby/internal/config.h" // defines USE_MJIT

#if USE_MJIT

#include "mjit_compiler.h"
#include "internal.h"
#include "internal/compile.h"
#include "internal/hash.h"
#include "internal/object.h"
#include "internal/variable.h"
#include "mjit.h"
#include "mjit_unit.h"
#include "yjit.h"
#include "vm_callinfo.h"
#include "vm_exec.h"
#include "vm_insnhelper.h"

#include "builtin.h"
#include "insns.inc"
#include "insns_info.inc"

struct case_dispatch_var {
    FILE *f;
    unsigned int base_pos;
    VALUE last_value;
};

static VALUE
rb_ptr(const char *type, const void *ptr)
{
    extern VALUE rb_mMJITC;
    VALUE rb_type = rb_funcall(rb_mMJITC, rb_intern(type), 0);
    return rb_funcall(rb_type, rb_intern("new"), 1, ULONG2NUM((size_t)ptr));
}

// Returns true if call cache is still not obsoleted and vm_cc_cme(cc)->def->type is available.
static bool
has_valid_method_type(CALL_CACHE cc)
{
    return vm_cc_cme(cc) != NULL;
}

// Returns true if iseq can use fastpath for setup, otherwise NULL. This becomes true in the same condition
// as CC_SET_FASTPATH (in vm_callee_setup_arg) is called from vm_call_iseq_setup.
static bool
fastpath_applied_iseq_p(const CALL_INFO ci, const CALL_CACHE cc, const rb_iseq_t *iseq)
{
    extern bool rb_simple_iseq_p(const rb_iseq_t *iseq);
    return iseq != NULL
        && !(vm_ci_flag(ci) & VM_CALL_KW_SPLAT) && rb_simple_iseq_p(iseq) // Top of vm_callee_setup_arg. In this case, opt_pc is 0.
        && vm_ci_argc(ci) == (unsigned int)ISEQ_BODY(iseq)->param.lead_num // exclude argument_arity_error (assumption: `calling->argc == ci->orig_argc` in send insns)
        && vm_call_iseq_optimizable_p(ci, cc); // CC_SET_FASTPATH condition
}

#define hidden_obj_p(obj) (!SPECIAL_CONST_P(obj) && !RBASIC(obj)->klass)

// TODO: Share this with iseq.c
static inline VALUE
obj_resurrect(VALUE obj)
{
    if (hidden_obj_p(obj)) {
        switch (BUILTIN_TYPE(obj)) {
          case T_STRING:
            obj = rb_str_resurrect(obj);
            break;
          case T_ARRAY:
            obj = rb_ary_resurrect(obj);
            break;
          case T_HASH:
            obj = rb_hash_resurrect(obj);
            break;
          default:
            break;
        }
    }
    return obj;
}

static int
cdhash_each(VALUE key, VALUE value, VALUE hash)
{
    rb_hash_aset(hash, obj_resurrect(key), value);
    return ST_CONTINUE;
}

#include "mjit_compile_attr.inc"

#if SIZEOF_LONG == SIZEOF_VOIDP
#define NUM2PTR(x) NUM2ULONG(x)
#define PTR2NUM(x) ULONG2NUM(x)
#elif SIZEOF_LONG_LONG == SIZEOF_VOIDP
#define NUM2PTR(x) NUM2ULL(x)
#define PTR2NUM(x) ULL2NUM(x)
#endif

extern int
mjit_capture_cc_entries(const struct rb_iseq_constant_body *compiled_iseq, const struct rb_iseq_constant_body *captured_iseq);

// Copy current is_entries and use it throughout the current compilation consistently.
// While ic->entry has been immutable since https://github.com/ruby/ruby/pull/3662,
// we still need this to avoid a race condition between entries and ivar_serial/max_ivar_index.
static void
mjit_capture_is_entries(const struct rb_iseq_constant_body *body, union iseq_inline_storage_entry *is_entries)
{
    if (is_entries == NULL)
        return;
    memcpy(is_entries, body->is_entries, sizeof(union iseq_inline_storage_entry) * ISEQ_IS_SIZE(body));
}

// Compile ISeq to C code in `f`. It returns true if it succeeds to compile.
bool
mjit_compile(FILE *f, const rb_iseq_t *iseq, const char *funcname, int id)
{
    bool original_call_p = mjit_call_p;
    mjit_call_p = false; // Avoid impacting JIT metrics by itself

    extern VALUE rb_mMJITCompiler;
    bool success = RTEST(rb_funcall(rb_mMJITCompiler, rb_intern("compile"), 4,
                PTR2NUM((VALUE)f), rb_ptr("rb_iseq_t", iseq), rb_str_new_cstr(funcname), INT2NUM(id)));

    mjit_call_p = original_call_p;
    return success;
}

//
// Primitive.methods
//

static VALUE
cdhash_to_hash(rb_execution_context_t *ec, VALUE self, VALUE cdhash_addr)
{
    VALUE hash = rb_hash_new();
    rb_hash_foreach((VALUE)NUM2PTR(cdhash_addr), cdhash_each, hash);
    return hash;
}

static VALUE
builtin_compile(rb_execution_context_t *ec, VALUE self, VALUE f_addr, VALUE bf_addr, VALUE index, VALUE stack_size, VALUE builtin_inline_p)
{
    FILE *f = (FILE *)NUM2PTR(f_addr);
    RB_BUILTIN bf = (RB_BUILTIN)NUM2PTR(bf_addr);
    bf->compiler(f, NIL_P(index) ? -1 : NUM2LONG(index), NUM2UINT(stack_size), RTEST(builtin_inline_p));
    return Qnil;
}

// Returns true if MJIT thinks this cc's opt_* insn may fallback to opt_send_without_block.
static VALUE
has_cache_for_send(rb_execution_context_t *ec, VALUE self, VALUE cc_addr, VALUE insn)
{
    extern bool rb_vm_opt_cfunc_p(CALL_CACHE cc, int insn);
    CALL_CACHE cc = (CALL_CACHE)NUM2PTR(cc_addr);
    bool has_cache = has_valid_method_type(cc) &&
        !(vm_cc_cme(cc)->def->type == VM_METHOD_TYPE_CFUNC && rb_vm_opt_cfunc_p(cc, NUM2INT(insn)));
    return RBOOL(has_cache);
}

extern bool rb_splat_or_kwargs_p(const struct rb_callinfo *restrict ci);

// An offsetof implementation that works for unnamed struct and union.
// Multiplying 8 for compatibility with libclang's offsetof.
#define OFFSETOF(ptr, member) RB_SIZE2NUM(((char *)&ptr.member - (char*)&ptr) * 8)

#define SIZEOF(type) RB_SIZE2NUM(sizeof(type))
#define SIGNED_TYPE_P(type) RBOOL((type)(-1) < (type)(1))

#include "mjit_c.rbinc"

#include "mjit_compiler.rbinc"

#endif // USE_MJIT