Commit f4df3aaa authored by Damien George's avatar Damien George
Browse files

py: Allow bytecode/native to put iter_buf on stack for simple for loops.

So that the "for x in it: ..." statement can now work without using the
heap (so long as the iterator argument fits in an iter_buf structure).
parent ae8d8675
......@@ -79,6 +79,7 @@
#define MP_BC_POP_BLOCK (0x44)
#define MP_BC_POP_EXCEPT (0x45)
#define MP_BC_UNWIND_JUMP (0x46) // rel byte code offset, 16-bit signed, in excess; then a byte
#define MP_BC_GET_ITER_STACK (0x47)
#define MP_BC_BUILD_TUPLE (0x50) // uint
#define MP_BC_BUILD_LIST (0x51) // uint
......
......@@ -1475,7 +1475,7 @@ STATIC void compile_for_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
uint pop_label = comp_next_label(comp);
compile_node(comp, pns->nodes[1]); // iterator
EMIT(get_iter);
EMIT_ARG(get_iter, true);
EMIT_ARG(label_assign, continue_label);
EMIT_ARG(for_iter, pop_label);
c_assign(comp, pns->nodes[0], ASSIGN_STORE); // variable
......@@ -1484,7 +1484,7 @@ STATIC void compile_for_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
EMIT_ARG(jump, continue_label);
}
EMIT_ARG(label_assign, pop_label);
EMIT(for_iter_end);
EMIT_ARG(for_iter_end, true);
// break/continue apply to outer loop (if any) in the else block
END_BREAK_CONTINUE_BLOCK
......@@ -1680,7 +1680,7 @@ STATIC void compile_with_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
}
STATIC void compile_yield_from(compiler_t *comp) {
EMIT(get_iter);
EMIT_ARG(get_iter, false);
EMIT_ARG(load_const_tok, MP_TOKEN_KW_NONE);
EMIT(yield_from);
}
......@@ -2372,7 +2372,7 @@ STATIC void compile_comprehension(compiler_t *comp, mp_parse_node_struct_t *pns,
close_over_variables_etc(comp, this_scope, 0, 0);
compile_node(comp, pns_comp_for->nodes[1]); // source of the iterator
EMIT(get_iter);
EMIT_ARG(get_iter, false);
EMIT_ARG(call_function, 1, 0, 0);
}
......@@ -2900,13 +2900,13 @@ STATIC void compile_scope_comp_iter(compiler_t *comp, mp_parse_node_struct_t *pn
// for loop
mp_parse_node_struct_t *pns_comp_for2 = (mp_parse_node_struct_t*)pn_iter;
compile_node(comp, pns_comp_for2->nodes[1]);
EMIT(get_iter);
EMIT_ARG(get_iter, false);
compile_scope_comp_iter(comp, pns_comp_for2, pn_inner_expr, for_depth + 1);
}
EMIT_ARG(jump, l_top);
EMIT_ARG(label_assign, l_end);
EMIT(for_iter_end);
EMIT_ARG(for_iter_end, false);
}
STATIC void check_for_doc_string(compiler_t *comp, mp_parse_node_t pn) {
......
......@@ -110,9 +110,9 @@ typedef struct _emit_method_table_t {
void (*setup_except)(emit_t *emit, mp_uint_t label);
void (*setup_finally)(emit_t *emit, mp_uint_t label);
void (*end_finally)(emit_t *emit);
void (*get_iter)(emit_t *emit);
void (*get_iter)(emit_t *emit, bool use_stack);
void (*for_iter)(emit_t *emit, mp_uint_t label);
void (*for_iter_end)(emit_t *emit);
void (*for_iter_end)(emit_t *emit, bool use_stack);
void (*pop_block)(emit_t *emit);
void (*pop_except)(emit_t *emit);
void (*unary_op)(emit_t *emit, mp_unary_op_t op);
......@@ -228,9 +228,9 @@ void mp_emit_bc_with_cleanup(emit_t *emit, mp_uint_t label);
void mp_emit_bc_setup_except(emit_t *emit, mp_uint_t label);
void mp_emit_bc_setup_finally(emit_t *emit, mp_uint_t label);
void mp_emit_bc_end_finally(emit_t *emit);
void mp_emit_bc_get_iter(emit_t *emit);
void mp_emit_bc_get_iter(emit_t *emit, bool use_stack);
void mp_emit_bc_for_iter(emit_t *emit, mp_uint_t label);
void mp_emit_bc_for_iter_end(emit_t *emit);
void mp_emit_bc_for_iter_end(emit_t *emit, bool use_stack);
void mp_emit_bc_pop_block(emit_t *emit);
void mp_emit_bc_pop_except(emit_t *emit);
void mp_emit_bc_unary_op(emit_t *emit, mp_unary_op_t op);
......
......@@ -734,6 +734,10 @@ void mp_emit_bc_unwind_jump(emit_t *emit, mp_uint_t label, mp_uint_t except_dept
if (label & MP_EMIT_BREAK_FROM_FOR) {
// need to pop the iterator if we are breaking out of a for loop
emit_write_bytecode_byte(emit, MP_BC_POP_TOP);
// also pop the iter_buf
for (size_t i = 0; i < sizeof(mp_obj_iter_buf_t) / sizeof(mp_obj_t); ++i) {
emit_write_bytecode_byte(emit, MP_BC_POP_TOP);
}
}
emit_write_bytecode_byte_signed_label(emit, MP_BC_JUMP, label & ~MP_EMIT_BREAK_FROM_FOR);
} else {
......@@ -773,9 +777,9 @@ void mp_emit_bc_end_finally(emit_t *emit) {
emit_write_bytecode_byte(emit, MP_BC_END_FINALLY);
}
void mp_emit_bc_get_iter(emit_t *emit) {
emit_bc_pre(emit, 0);
emit_write_bytecode_byte(emit, MP_BC_GET_ITER);
void mp_emit_bc_get_iter(emit_t *emit, bool use_stack) {
emit_bc_pre(emit, use_stack ? sizeof(mp_obj_iter_buf_t) / sizeof(mp_obj_t) : 0);
emit_write_bytecode_byte(emit, use_stack ? MP_BC_GET_ITER_STACK : MP_BC_GET_ITER);
}
void mp_emit_bc_for_iter(emit_t *emit, mp_uint_t label) {
......@@ -783,8 +787,13 @@ void mp_emit_bc_for_iter(emit_t *emit, mp_uint_t label) {
emit_write_bytecode_byte_unsigned_label(emit, MP_BC_FOR_ITER, label);
}
void mp_emit_bc_for_iter_end(emit_t *emit) {
void mp_emit_bc_for_iter_end(emit_t *emit, bool use_stack) {
emit_bc_pre(emit, -1);
if (use_stack) {
for (size_t i = 0; i < sizeof(mp_obj_iter_buf_t) / sizeof(mp_obj_t); ++i) {
mp_emit_bc_pop_top(emit);
}
}
}
void mp_emit_bc_pop_block(emit_t *emit) {
......
......@@ -1799,14 +1799,19 @@ STATIC void emit_native_end_finally(emit_t *emit) {
emit_post(emit);
}
STATIC void emit_native_get_iter(emit_t *emit) {
STATIC void emit_native_get_iter(emit_t *emit, bool use_stack) {
// perhaps the difficult one, as we want to rewrite for loops using native code
// in cases where we iterate over a Python object, can we use normal runtime calls?
vtype_kind_t vtype;
emit_pre_pop_reg(emit, &vtype, REG_ARG_1);
assert(vtype == VTYPE_PYOBJ);
assert(0); // TODO allocate memory for iter_buf
if (use_stack) {
emit_get_stack_pointer_to_reg_for_push(emit, REG_ARG_2, sizeof(mp_obj_iter_buf_t) / sizeof(mp_obj_t));
} else {
// mp_getiter will allocate the iter_buf on the heap
ASM_MOV_IMM_TO_REG(emit->as, 0, REG_ARG_2);
}
emit_call(emit, MP_F_GETITER);
emit_post_push_reg(emit, VTYPE_PYOBJ, REG_RET);
}
......@@ -1822,10 +1827,13 @@ STATIC void emit_native_for_iter(emit_t *emit, mp_uint_t label) {
emit_post_push_reg(emit, VTYPE_PYOBJ, REG_RET);
}
STATIC void emit_native_for_iter_end(emit_t *emit) {
STATIC void emit_native_for_iter_end(emit_t *emit, bool use_stack) {
// adjust stack counter (we get here from for_iter ending, which popped the value for us)
emit_native_pre(emit);
adjust_stack(emit, -1);
if (use_stack) {
adjust_stack(emit, -(sizeof(mp_obj_iter_buf_t) / sizeof(mp_obj_t)));
}
emit_post(emit);
}
......
......@@ -387,6 +387,10 @@ const byte *mp_bytecode_print_str(const byte *ip) {
printf("GET_ITER");
break;
case MP_BC_GET_ITER_STACK:
printf("GET_ITER_STACK");
break;
case MP_BC_FOR_ITER:
DECODE_ULABEL; // the jump offset if iteration finishes; for labels are always forward
printf("FOR_ITER " UINT_FMT, (mp_uint_t)(ip + unum - mp_showbc_code_start));
......
......@@ -681,7 +681,9 @@ unwind_jump:;
}
ip = (const byte*)MP_OBJ_TO_PTR(POP()); // pop destination ip for jump
if (unum != 0) {
// pop iter and iter_buf
sp--;
sp -= sizeof(mp_obj_iter_buf_t) / sizeof(mp_obj_t);
}
DISPATCH_WITH_PEND_EXC_CHECK();
}
......@@ -726,6 +728,15 @@ unwind_jump:;
SET_TOP(mp_getiter(TOP(), NULL));
DISPATCH();
ENTRY(MP_BC_GET_ITER_STACK): {
MARK_EXC_IP_SELECTIVE();
mp_obj_t obj = TOP();
mp_obj_iter_buf_t *iter_buf = (mp_obj_iter_buf_t*)sp;
sp += sizeof(mp_obj_iter_buf_t) / sizeof(mp_obj_t);
SET_TOP(mp_getiter(obj, iter_buf));
DISPATCH();
}
ENTRY(MP_BC_FOR_ITER): {
MARK_EXC_IP_SELECTIVE();
DECODE_ULABEL; // the jump offset if iteration finishes; for labels are always forward
......
......@@ -73,6 +73,7 @@ static const void *const entry_table[256] = {
[MP_BC_SETUP_FINALLY] = &&entry_MP_BC_SETUP_FINALLY,
[MP_BC_END_FINALLY] = &&entry_MP_BC_END_FINALLY,
[MP_BC_GET_ITER] = &&entry_MP_BC_GET_ITER,
[MP_BC_GET_ITER_STACK] = &&entry_MP_BC_GET_ITER_STACK,
[MP_BC_FOR_ITER] = &&entry_MP_BC_FOR_ITER,
[MP_BC_POP_BLOCK] = &&entry_MP_BC_POP_BLOCK,
[MP_BC_POP_EXCEPT] = &&entry_MP_BC_POP_EXCEPT,
......
......@@ -31,7 +31,7 @@ File cmdline/cmd_showbc.py, code block 'f' (descriptor: \.\+, bytecode @\.\+ byt
Raw bytecode (code_info_size=\\d\+, bytecode_size=\\d\+):
########
\.\+rg names:
(N_STATE 22)
(N_STATE 23)
(N_EXC_STACK 2)
(INIT_CELL 14)
(INIT_CELL 15)
......@@ -245,12 +245,16 @@ Raw bytecode (code_info_size=\\d\+, bytecode_size=\\d\+):
\\d\+ LOAD_FAST 0
\\d\+ STORE_FAST 0
\\d\+ LOAD_DEREF 14
\\d\+ GET_ITER
\\d\+ GET_ITER_STACK
\\d\+ FOR_ITER \\d\+
\\d\+ STORE_FAST 0
\\d\+ LOAD_FAST 1
\\d\+ POP_TOP
\\d\+ JUMP \\d\+
\\d\+ POP_TOP
\\d\+ POP_TOP
\\d\+ POP_TOP
\\d\+ POP_TOP
\\d\+ SETUP_FINALLY \\d\+
\\d\+ SETUP_EXCEPT \\d\+
\\d\+ JUMP \\d\+
......
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