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ruby--ruby/ujit_compile.c
2021-10-20 18:19:23 -04:00

236 lines
5.8 KiB
C

#include <assert.h>
#include "insns.inc"
#include "internal.h"
#include "vm_core.h"
#include "vm_callinfo.h"
#include "builtin.h"
#include "insns_info.inc"
#include "ujit_compile.h"
#include "ujit_asm.h"
// TODO: give ujit_examples.h some more meaningful file name
#include "ujit_examples.h"
// Code generation context
typedef struct ctx_struct
{
// TODO: virtual stack pointer handling
} ctx_t;
// Code generation function
typedef void (*codegen_fn)(codeblock_t* cb, ctx_t* ctx);
// Map from YARV opcodes to code generation functions
static st_table *gen_fns;
// Code block into which we write machine code
static codeblock_t block;
static codeblock_t* cb = NULL;
// Hash table of encoded instructions
extern st_table *rb_encoded_insn_data;
static void ujit_init();
// Ruby instruction entry
static void
ujit_instr_entry(codeblock_t* cb)
{
for (size_t i = 0; i < sizeof(ujit_pre_call_bytes); ++i)
cb_write_byte(cb, ujit_pre_call_bytes[i]);
}
// Ruby instruction exit
static void
ujit_instr_exit(codeblock_t* cb)
{
for (size_t i = 0; i < sizeof(ujit_post_call_bytes); ++i)
cb_write_byte(cb, ujit_post_call_bytes[i]);
}
// Keep track of mapping from instructions to generated code
// See comment for rb_encoded_insn_data in iseq.c
static void
addr2insn_bookkeeping(void *code_ptr, int insn)
{
const void * const *table = rb_vm_get_insns_address_table();
const void * const translated_address = table[insn];
st_data_t encoded_insn_data;
if (st_lookup(rb_encoded_insn_data, (st_data_t)translated_address, &encoded_insn_data)) {
st_insert(rb_encoded_insn_data, (st_data_t)code_ptr, encoded_insn_data);
}
else {
rb_bug("ujit: failed to find info for original instruction while dealing with addr2insn");
}
}
// Generate a chunk of machine code for one individual bytecode instruction
// Eventually, this will handle multiple instructions in a sequence
//
// MicroJIT code gets a pointer to the cfp as the first argument in RSI
// See rb_ujit_empty_func(rb_control_frame_t *cfp) in iseq.c
uint8_t *
ujit_compile_insn(rb_iseq_t *iseq, size_t insn_idx)
{
// If not previously done, initialize ujit
if (!cb)
{
ujit_init();
}
if (cb->write_pos + 1024 >= cb->mem_size)
{
rb_bug("out of executable memory");
}
int insn = (int)iseq->body->iseq_encoded[insn_idx];
int len = insn_len(insn);
//const char* name = insn_name(insn);
//printf("%s\n", name);
// Lookup the codegen function for this instruction
st_data_t st_gen_fn;
int found = rb_st_lookup(gen_fns, insn, &st_gen_fn);
if (!found)
return 0;
codegen_fn gen_fn = (codegen_fn)st_gen_fn;
// Compute the address of the next instruction
void *next_pc = &iseq->body->iseq_encoded[insn_idx + len];
// Get a pointer to the current write position in the code block
uint8_t *code_ptr = &cb->mem_block[cb->write_pos];
//printf("write pos: %ld\n", cb->write_pos);
// Write the pre call bytes
ujit_instr_entry(cb);
// TODO: create codegen context
// Call the code generation function
gen_fn(cb, NULL);
// Directly return the next PC, which is a constant
mov(cb, RAX, const_ptr_opnd(next_pc));
// Write the post call bytes
ujit_instr_exit(cb);
addr2insn_bookkeeping(code_ptr, insn);
return code_ptr;
/*
if (insn == BIN(putobject_INT2FIX_0_) || insn == BIN(putobject_INT2FIX_1_))
{
// Load current SP into RAX
mov(cb, RAX, mem_opnd(64, RDI, 8));
// Write constant at SP
int cst_val = (insn == BIN(putobject_INT2FIX_0_))? 0:1;
mov(cb, mem_opnd(64, RAX, 0), imm_opnd(INT2FIX(cst_val)));
// Load incremented SP into RCX
lea(cb, RCX, mem_opnd(64, RAX, 8));
// Write back incremented SP
mov(cb, mem_opnd(64, RDI, 8), RCX);
// Directly return the next PC, which is a constant
mov(cb, RAX, const_ptr_opnd(next_pc));
// Write the post call bytes
ujit_instr_exit(cb);
addr2insn_bookkeeping(code_ptr, insn);
return code_ptr;
}
*/
// TODO: implement putself
/*
if (insn == BIN(putself))
{
}
*/
// TODO: implement putobject
/*
if (insn == BIN(putobject))
{
}
*/
/*
if (insn == BIN(getlocal_WC_0))
{
//printf("compiling getlocal_WC_0\n");
// Load current SP from CFP
mov(cb, RAX, mem_opnd(64, RDI, 8));
// Load block pointer from CFP
mov(cb, RDX, mem_opnd(64, RDI, 32));
// TODO: we may want a macro or helper function to get insn operands
// Compute the offset from BP to the local
int32_t opnd0 = (int)iseq->body->iseq_encoded[insn_idx+1];
const int32_t offs = -8 * opnd0;
// Load the local from the block
mov(cb, RCX, mem_opnd(64, RDX, offs));
// Write the local at SP
mov(cb, mem_opnd(64, RAX, 0), RCX);
// Compute address of incremented SP
lea(cb, RCX, mem_opnd(64, RAX, 8));
// Write back incremented SP
mov(cb, mem_opnd(64, RDI, 8), RCX);
// Directly return the next PC, which is a constant
mov(cb, RAX, const_ptr_opnd(next_pc));
// Write the post call bytes
ujit_instr_exit(cb);
addr2insn_bookkeeping(code_ptr, insn);
}
*/
}
void gen_nop(codeblock_t* cb, ctx_t* ctx)
{
}
void gen_pop(codeblock_t* cb, ctx_t* ctx)
{
// Decrement SP
sub(cb, mem_opnd(64, RDI, 8), imm_opnd(8));
}
static void ujit_init()
{
// 4MB ought to be enough for anybody
cb = &block;
cb_init(cb, 4000000);
// Initialize the codegen function table
gen_fns = rb_st_init_numtable();
// Map YARV opcodes to the corresponding codegen functions
st_insert(gen_fns, (st_data_t)BIN(nop), (st_data_t)&gen_nop);
st_insert(gen_fns, (st_data_t)BIN(pop), (st_data_t)&gen_pop);
}