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Implement fast path for string dimensions in JIT #23767

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Implement fast path for string dimensions in JIT #23767

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62 changes: 48 additions & 14 deletions ext/opcache/jit/zend_jit_ir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12720,25 +12720,59 @@ static int zend_jit_fetch_dim_read(zend_jit_ctx *jit,
ir_IF_TRUE(if_type);
}
}
jit_SET_EX_OPLINE(jit, opline);
str_ref = jit_Z_PTR(jit, op1_addr);
if (opline->opcode != ZEND_FETCH_DIM_IS) {
ir_ref ref;
if (opline->opcode != ZEND_FETCH_DIM_IS
&& (op2_info & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_GUARD)) == MAY_BE_LONG) {
ir_ref offset_ref = jit_Z_LVAL(jit, op2_addr);
ir_ref len_ref = ir_LOAD_L(ir_ADD_OFFSET(str_ref, offsetof(zend_string, len)));
ir_ref real_offset_ref = offset_ref;
if (!op2_range || op2_range->min < 0) {
// JIT: if (offset < 0) offset += ZSTR_LEN(str);
/* Branchless way to add -1 for negative offsets to the string length. */
real_offset_ref = ir_ADD_L(offset_ref,
ir_AND_L(len_ref,
ir_SAR_L(offset_ref, ir_CONST_LONG(SIZEOF_ZEND_LONG * 8 - 1))));
}

/* An offset that is still negative wraps around and fails this check as well. */
ir_ref if_in_range = ir_IF(ir_ULT(real_offset_ref, len_ref));

ir_IF_TRUE(if_in_range);
// JIT: result = ZSTR_CHAR((uint8_t)ZSTR_VAL(str)[offset]);
ir_ref ref = ir_LOAD_A(
ir_ADD_A(
ir_CONST_ADDR(zend_one_char_string),
ir_MUL_A(
ir_ZEXT_A(
ir_LOAD_U8(
ir_ADD_A(ir_ADD_OFFSET(str_ref, offsetof(zend_string, val)),
ir_BITCAST_A(real_offset_ref)))),
ir_CONST_ADDR(sizeof(zend_string*)))));
ir_ref fast_path = ir_END();

ir_IF_FALSE_cold(if_in_range);
jit_SET_EX_OPLINE(jit, opline);
ir_ref slow_ref = ir_CALL_2(IR_ADDR, ir_CONST_FC_FUNC(zend_jit_fetch_dim_str_offset_r_helper),
str_ref, offset_ref);

if ((op2_info & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_GUARD)) == MAY_BE_LONG) {
ref = ir_CALL_2(IR_ADDR, ir_CONST_FC_FUNC(zend_jit_fetch_dim_str_offset_r_helper),
str_ref, jit_Z_LVAL(jit, op2_addr));
} else {
ref = ir_CALL_2(IR_ADDR, ir_CONST_FC_FUNC(zend_jit_fetch_dim_str_r_helper),
str_ref, jit_ZVAL_ADDR(jit, op2_addr));
}
ir_MERGE_WITH(fast_path);
ref = ir_PHI_2(IR_ADDR, slow_ref, ref);
jit_set_Z_PTR(jit, res_addr, ref);
jit_set_Z_TYPE_INFO(jit, res_addr, IS_STRING);
} else {
ir_CALL_3(IR_VOID, ir_CONST_FC_FUNC(zend_jit_fetch_dim_str_is_helper),
str_ref,
jit_ZVAL_ADDR(jit, op2_addr),
jit_ZVAL_ADDR(jit, res_addr));
jit_SET_EX_OPLINE(jit, opline);
if (opline->opcode != ZEND_FETCH_DIM_IS) {
ir_ref ref = ir_CALL_2(IR_ADDR, ir_CONST_FC_FUNC(zend_jit_fetch_dim_str_r_helper),
str_ref, jit_ZVAL_ADDR(jit, op2_addr));

jit_set_Z_PTR(jit, res_addr, ref);
jit_set_Z_TYPE_INFO(jit, res_addr, IS_STRING);
} else {
ir_CALL_3(IR_VOID, ir_CONST_FC_FUNC(zend_jit_fetch_dim_str_is_helper),
str_ref,
jit_ZVAL_ADDR(jit, op2_addr),
jit_ZVAL_ADDR(jit, res_addr));
}
}
ir_END_list(end_inputs);
}
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