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py: Implement break/continue from an exception with finally.

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Still todo: break/continue from within the finally block itself.
This commit is contained in:
Damien George
2014-02-01 20:08:18 +00:00
parent a908202d60
commit cbddb279bb
8 changed files with 104 additions and 82 deletions
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85
py/compile.c
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@@ -50,7 +50,8 @@ typedef struct _compiler_t {
int break_label;
int continue_label;
int except_nest_level;
int break_continue_except_level;
int cur_except_level; // increased for SETUP_EXCEPT, SETUP_FINALLY; decreased for POP_BLOCK, POP_EXCEPT
int n_arg_keyword;
bool have_star_arg;
@@ -1080,18 +1081,14 @@ void compile_break_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
if (comp->break_label == 0) {
printf("ERROR: cannot break from here\n");
}
EMIT_ARG(break_loop, comp->break_label);
EMIT_ARG(break_loop, comp->break_label, comp->cur_except_level - comp->break_continue_except_level);
}
void compile_continue_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
if (comp->continue_label == 0) {
printf("ERROR: cannot continue from here\n");
}
if (comp->except_nest_level > 0) {
EMIT_ARG(continue_loop, comp->continue_label);
} else {
EMIT_ARG(jump, comp->continue_label);
}
EMIT_ARG(continue_loop, comp->continue_label, comp->cur_except_level - comp->break_continue_except_level);
}
void compile_return_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
@@ -1387,15 +1384,22 @@ void compile_if_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
EMIT_ARG(label_assign, l_end);
}
#define START_BREAK_CONTINUE_BLOCK \
int old_break_label = comp->break_label; \
int old_continue_label = comp->continue_label; \
int break_label = comp_next_label(comp); \
int continue_label = comp_next_label(comp); \
comp->break_label = break_label; \
comp->continue_label = continue_label; \
comp->break_continue_except_level = comp->cur_except_level;
#define END_BREAK_CONTINUE_BLOCK \
comp->break_label = old_break_label; \
comp->continue_label = old_continue_label; \
comp->break_continue_except_level = comp->cur_except_level;
void compile_while_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
int old_break_label = comp->break_label;
int old_continue_label = comp->continue_label;
int break_label = comp_next_label(comp);
int continue_label = comp_next_label(comp);
comp->break_label = break_label;
comp->continue_label = continue_label;
START_BREAK_CONTINUE_BLOCK
// compared to CPython, we have an optimised version of while loops
#if MICROPY_EMIT_CPYTHON
@@ -1423,8 +1427,7 @@ void compile_while_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
#endif
// break/continue apply to outer loop (if any) in the else block
comp->break_label = old_break_label;
comp->continue_label = old_continue_label;
END_BREAK_CONTINUE_BLOCK
compile_node(comp, pns->nodes[2]); // else
@@ -1434,14 +1437,7 @@ void compile_while_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
// TODO preload end and step onto stack if they are not constants
// TODO check if step is negative and do opposite test
void compile_for_stmt_optimised_range(compiler_t *comp, mp_parse_node_t pn_var, mp_parse_node_t pn_start, mp_parse_node_t pn_end, mp_parse_node_t pn_step, mp_parse_node_t pn_body, mp_parse_node_t pn_else) {
int old_break_label = comp->break_label;
int old_continue_label = comp->continue_label;
int break_label = comp_next_label(comp);
int continue_label = comp_next_label(comp);
comp->break_label = break_label;
comp->continue_label = continue_label;
START_BREAK_CONTINUE_BLOCK
int top_label = comp_next_label(comp);
int entry_label = comp_next_label(comp);
@@ -1477,8 +1473,7 @@ void compile_for_stmt_optimised_range(compiler_t *comp, mp_parse_node_t pn_var,
EMIT_ARG(pop_jump_if_true, top_label);
// break/continue apply to outer loop (if any) in the else block
comp->break_label = old_break_label;
comp->continue_label = old_continue_label;
END_BREAK_CONTINUE_BLOCK
compile_node(comp, pn_else);
@@ -1531,18 +1526,11 @@ void compile_for_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
}
#endif
int old_break_label = comp->break_label;
int old_continue_label = comp->continue_label;
START_BREAK_CONTINUE_BLOCK
int for_label = comp_next_label(comp);
int pop_label = comp_next_label(comp);
int end_label = comp_next_label(comp);
int break_label = comp_next_label(comp);
comp->continue_label = for_label;
comp->break_label = break_label;
// I don't think our implementation needs SETUP_LOOP/POP_BLOCK for for-statements
#if MICROPY_EMIT_CPYTHON
EMIT_ARG(setup_loop, end_label);
@@ -1550,19 +1538,18 @@ void compile_for_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
compile_node(comp, pns->nodes[1]); // iterator
EMIT(get_iter);
EMIT_ARG(label_assign, for_label);
EMIT_ARG(label_assign, continue_label);
EMIT_ARG(for_iter, pop_label);
c_assign(comp, pns->nodes[0], ASSIGN_STORE); // variable
compile_node(comp, pns->nodes[2]); // body
if (!EMIT(last_emit_was_return_value)) {
EMIT_ARG(jump, for_label);
EMIT_ARG(jump, continue_label);
}
EMIT_ARG(label_assign, pop_label);
EMIT(for_iter_end);
// break/continue apply to outer loop (if any) in the else block
comp->break_label = old_break_label;
comp->continue_label = old_continue_label;
END_BREAK_CONTINUE_BLOCK
#if MICROPY_EMIT_CPYTHON
EMIT(pop_block);
@@ -1582,8 +1569,10 @@ void compile_try_except(compiler_t *comp, mp_parse_node_t pn_body, int n_except,
int stack_size = EMIT(get_stack_size);
int l1 = comp_next_label(comp);
int success_label = comp_next_label(comp);
comp->except_nest_level += 1; // for correct handling of continue
EMIT_ARG(setup_except, l1);
comp->cur_except_level += 1;
compile_node(comp, pn_body); // body
EMIT(pop_block);
EMIT_ARG(jump, success_label);
@@ -1634,6 +1623,7 @@ void compile_try_except(compiler_t *comp, mp_parse_node_t pn_body, int n_except,
if (qstr_exception_local != 0) {
l3 = comp_next_label(comp);
EMIT_ARG(setup_finally, l3);
comp->cur_except_level += 1;
}
compile_node(comp, pns_except->nodes[1]);
if (qstr_exception_local != 0) {
@@ -1646,15 +1636,18 @@ void compile_try_except(compiler_t *comp, mp_parse_node_t pn_body, int n_except,
EMIT_ARG(load_const_tok, MP_TOKEN_KW_NONE);
EMIT_ARG(store_id, qstr_exception_local);
EMIT_ARG(delete_id, qstr_exception_local);
comp->cur_except_level -= 1;
EMIT(end_finally);
}
EMIT_ARG(jump, l2);
EMIT_ARG(label_assign, end_finally_label);
}
comp->cur_except_level -= 1;
EMIT(end_finally);
EMIT_ARG(label_assign, success_label);
comp->except_nest_level -= 1;
compile_node(comp, pn_else); // else block, can be null
EMIT_ARG(label_assign, l2);
EMIT_ARG(set_stack_size, stack_size);
@@ -1664,7 +1657,10 @@ void compile_try_finally(compiler_t *comp, mp_parse_node_t pn_body, int n_except
// don't understand how the stack works with exceptions, so we force it to return to the correct value
int stack_size = EMIT(get_stack_size);
int l_finally_block = comp_next_label(comp);
EMIT_ARG(setup_finally, l_finally_block);
comp->cur_except_level += 1;
if (n_except == 0) {
assert(MP_PARSE_NODE_IS_NULL(pn_else));
compile_node(comp, pn_body);
@@ -1675,7 +1671,10 @@ void compile_try_finally(compiler_t *comp, mp_parse_node_t pn_body, int n_except
EMIT_ARG(load_const_tok, MP_TOKEN_KW_NONE);
EMIT_ARG(label_assign, l_finally_block);
compile_node(comp, pn_finally);
comp->cur_except_level -= 1;
EMIT(end_finally);
EMIT_ARG(set_stack_size, stack_size);
}
@@ -3056,7 +3055,9 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, bool is_repl) {
comp->break_label = 0;
comp->continue_label = 0;
comp->except_nest_level = 0;
comp->break_continue_except_level = 0;
comp->cur_except_level = 0;
comp->scope_head = NULL;
comp->scope_cur = NULL;