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Avoid generating redundant interpreter exit code after branches

This commit is contained in:
Maxime Chevalier-Boisvert 2021-01-07 17:09:25 -05:00 committed by Alan Wu
parent 97cffcf79a
commit 1744c15578
3 changed files with 87 additions and 56 deletions

View file

@ -173,6 +173,9 @@ ujit_compile_block(const rb_iseq_t *iseq, uint32_t insn_idx, ctx_t* ctx, uint32_
// Get a pointer to the current write position in the code block
uint8_t *code_ptr = cb_get_ptr(cb, cb->write_pos);
// Last operation that was successfully compiled
opdesc_t* p_last_op = NULL;
// Initialize JIT state object
jitstate_t jit = { 0 };
jit.iseq = iseq;
@ -187,42 +190,40 @@ ujit_compile_block(const rb_iseq_t *iseq, uint32_t insn_idx, ctx_t* ctx, uint32_
// Get the current opcode
int opcode = jit_get_opcode(&jit);
//fprintf(stderr, "compiling %s\n", insn_name(opcode));
// Lookup the codegen function for this instruction
st_data_t st_gen_fn;
if (!rb_st_lookup(gen_fns, opcode, &st_gen_fn)) {
//print_int(cb, imm_opnd(num_instrs));
//print_str(cb, insn_name(opcode));
st_data_t st_op_desc;
if (!rb_st_lookup(gen_fns, opcode, &st_op_desc)) {
break;
}
//fprintf(stderr, "compiling %s\n", insn_name(opcode));
//print_str(cb, insn_name(opcode));
// Call the code generation function
codegen_fn gen_fn = (codegen_fn)st_gen_fn;
if (!gen_fn(&jit, ctx)) {
opdesc_t* p_desc = (opdesc_t*)st_op_desc;
bool success = p_desc->gen_fn(&jit, ctx);
// If we can't compile this instruction
if (!success) {
break;
}
// Move to the next instruction
p_last_op = p_desc;
insn_idx += insn_len(opcode);
(*num_instrs)++;
// Ensure we only have one send per region. Our code invalidation mechanism can't
// invalidate running code and one send could invalidate the other if we had
// multiple in the same region.
if (opcode == BIN(opt_send_without_block)) {
// If this instruction terminates this block
if (p_desc->is_branch) {
break;
}
}
//print_str(cb, "exiting to interpreter\n");
// FIXME: we only need to generate an exit if an instruction fails to compile
//
// If the last instruction compiled did not properly terminate the block
// Generate code to exit to the interpreter
ujit_gen_exit(&jit, ctx, cb, &encoded[insn_idx]);
if (!p_last_op || !p_last_op->is_branch) {
ujit_gen_exit(&jit, ctx, cb, &encoded[insn_idx]);
}
if (UJIT_DUMP_MODE >= 2) {
// Dump list of compiled instrutions
@ -976,6 +977,21 @@ gen_branchunless(jitstate_t* jit, ctx_t* ctx)
return true;
}
void ujit_reg_op(int opcode, codegen_fn gen_fn, bool is_branch)
{
// Check that the op wasn't previously registered
st_data_t st_desc;
if (rb_st_lookup(gen_fns, opcode, &st_desc)) {
rb_bug("op already registered");
}
opdesc_t* p_desc = (opdesc_t*)malloc(sizeof(opdesc_t));
p_desc->gen_fn = gen_fn;
p_desc->is_branch = is_branch;
st_insert(gen_fns, (st_data_t)opcode, (st_data_t)p_desc);
}
void
ujit_init_codegen(void)
{
@ -991,21 +1007,21 @@ ujit_init_codegen(void)
gen_fns = rb_st_init_numtable();
// Map YARV opcodes to the corresponding codegen functions
st_insert(gen_fns, (st_data_t)BIN(dup), (st_data_t)&gen_dup);
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);
st_insert(gen_fns, (st_data_t)BIN(putnil), (st_data_t)&gen_putnil);
st_insert(gen_fns, (st_data_t)BIN(putobject), (st_data_t)&gen_putobject);
st_insert(gen_fns, (st_data_t)BIN(putobject_INT2FIX_0_), (st_data_t)&gen_putobject_int2fix);
st_insert(gen_fns, (st_data_t)BIN(putobject_INT2FIX_1_), (st_data_t)&gen_putobject_int2fix);
st_insert(gen_fns, (st_data_t)BIN(putself), (st_data_t)&gen_putself);
st_insert(gen_fns, (st_data_t)BIN(getlocal_WC_0), (st_data_t)&gen_getlocal_wc0);
st_insert(gen_fns, (st_data_t)BIN(setlocal_WC_0), (st_data_t)&gen_setlocal_wc0);
st_insert(gen_fns, (st_data_t)BIN(getinstancevariable), (st_data_t)&gen_getinstancevariable);
st_insert(gen_fns, (st_data_t)BIN(setinstancevariable), (st_data_t)&gen_setinstancevariable);
st_insert(gen_fns, (st_data_t)BIN(opt_lt), (st_data_t)&gen_opt_lt);
st_insert(gen_fns, (st_data_t)BIN(opt_minus), (st_data_t)&gen_opt_minus);
st_insert(gen_fns, (st_data_t)BIN(opt_plus), (st_data_t)&gen_opt_plus);
//st_insert(gen_fns, (st_data_t)BIN(opt_send_without_block), (st_data_t)&gen_opt_send_without_block);
st_insert(gen_fns, (st_data_t)BIN(branchunless), (st_data_t)&gen_branchunless);
ujit_reg_op(BIN(dup), gen_dup, false);
ujit_reg_op(BIN(nop), gen_nop, false);
ujit_reg_op(BIN(pop), gen_pop, false);
ujit_reg_op(BIN(putnil), gen_putnil, false);
ujit_reg_op(BIN(putobject), gen_putobject, false);
ujit_reg_op(BIN(putobject_INT2FIX_0_), gen_putobject_int2fix, false);
ujit_reg_op(BIN(putobject_INT2FIX_1_), gen_putobject_int2fix, false);
ujit_reg_op(BIN(putself), gen_putself, false);
ujit_reg_op(BIN(getlocal_WC_0), gen_getlocal_wc0, false);
ujit_reg_op(BIN(setlocal_WC_0), gen_setlocal_wc0, false);
ujit_reg_op(BIN(getinstancevariable), gen_getinstancevariable, false);
ujit_reg_op(BIN(setinstancevariable), gen_setinstancevariable, false);
ujit_reg_op(BIN(opt_lt), gen_opt_lt, false);
ujit_reg_op(BIN(opt_minus), gen_opt_minus, false);
ujit_reg_op(BIN(opt_plus), gen_opt_plus, false);
//ujit_reg_op(BIN(opt_send_without_block), gen_opt_send_without_block);
ujit_reg_op(BIN(branchunless), gen_branchunless, true);
}

View file

@ -28,6 +28,18 @@ typedef struct JITState
// Code generation function signature
typedef bool (*codegen_fn)(jitstate_t* jit, ctx_t* ctx);
// Meta-information associated with a given opcode
typedef struct OpDesc
{
// Code generation function
codegen_fn gen_fn;
// Indicates that this is a branch instruction
// which terminates a block
bool is_branch;
} opdesc_t;
uint8_t* ujit_compile_entry(const rb_iseq_t *iseq, uint32_t insn_idx);
uint8_t *ujit_compile_block(const rb_iseq_t *iseq, uint32_t insn_idx, ctx_t* ctx, uint32_t* num_instrs);

View file

@ -69,28 +69,6 @@ ctx_stack_opnd(ctx_t* ctx, int32_t idx)
return opnd;
}
int blockid_cmp(st_data_t arg0, st_data_t arg1)
{
const blockid_t *block0 = (const blockid_t*)arg0;
const blockid_t *block1 = (const blockid_t*)arg1;
return block0->iseq == block1->iseq && block0->idx == block1->idx;
}
st_index_t blockid_hash(st_data_t arg)
{
const blockid_t *blockid = (const blockid_t*)arg;
st_index_t hash0 = st_numhash((st_data_t)blockid->iseq);
st_index_t hash1 = st_numhash((st_data_t)(uint64_t)blockid->idx);
// Use XOR to combine the hashes
return hash0 ^ hash1;
}
static const struct st_hash_type hashtype_blockid = {
blockid_cmp,
blockid_hash,
};
// Retrieve a basic block version for an (iseq, idx) tuple
uint8_t* find_block_version(blockid_t block)
{
@ -113,10 +91,13 @@ uint8_t* branch_stub_hit(uint32_t branch_idx, uint32_t target_idx)
blockid_t target = branch->targets[target_idx];
//fprintf(stderr, "\nstub hit, branch idx: %d, target idx: %d\n", branch_idx, target_idx);
//fprintf(stderr, "cb->write_pos=%ld\n", cb->write_pos);
//fprintf(stderr, "branch->end_pos=%d\n", branch->end_pos);
// If either of the target blocks will be placed next
if (cb->write_pos == branch->end_pos)
{
//fprintf(stderr, "target idx %d will be placed next\n", target_idx);
branch->shape = (uint8_t)target_idx;
// Rewrite the branch with the new, potentially more compact shape
@ -222,6 +203,28 @@ void gen_branch(ctx_t* ctx, blockid_t target0, blockid_t target1, branchgen_fn g
num_branches++;
}
int blockid_cmp(st_data_t arg0, st_data_t arg1)
{
const blockid_t *block0 = (const blockid_t*)arg0;
const blockid_t *block1 = (const blockid_t*)arg1;
return block0->iseq == block1->iseq && block0->idx == block1->idx;
}
st_index_t blockid_hash(st_data_t arg)
{
const blockid_t *blockid = (const blockid_t*)arg;
st_index_t hash0 = st_numhash((st_data_t)blockid->iseq);
st_index_t hash1 = st_numhash((st_data_t)(uint64_t)blockid->idx);
// Use XOR to combine the hashes
return hash0 ^ hash1;
}
static const struct st_hash_type hashtype_blockid = {
blockid_cmp,
blockid_hash,
};
void
ujit_init_core(void)
{