diff options
Diffstat (limited to 'py')
| -rw-r--r-- | py/compile.c | 23 | ||||
| -rw-r--r-- | py/vstr.c | 4 |
2 files changed, 20 insertions, 7 deletions
diff --git a/py/compile.c b/py/compile.c index 43253a926b..25830eb6f9 100644 --- a/py/compile.c +++ b/py/compile.c @@ -1534,35 +1534,41 @@ 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 +// Note that, as per semantics of for .. range, the final failing value should not be stored in the loop variable +// And, if the loop never runs, the loop variable should never be assigned 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) { START_BREAK_CONTINUE_BLOCK int top_label = comp_next_label(comp); int entry_label = comp_next_label(comp); - // compile: var = start + // compile: start, duplicated on stack compile_node(comp, pn_start); - c_assign(comp, pn_var, ASSIGN_STORE); + EMIT(dup_top); EMIT_ARG(jump, entry_label); EMIT_ARG(label_assign, top_label); + // at this point we actually have 1 less element on the stack + EMIT_ARG(set_stack_size, EMIT(get_stack_size) - 1); + + // store next value to var + c_assign(comp, pn_var, ASSIGN_STORE); + // compile body compile_node(comp, pn_body); EMIT_ARG(label_assign, continue_label); - // compile: var += step - c_assign(comp, pn_var, ASSIGN_AUG_LOAD); + // compile: var + step, duplicated on stack + compile_node(comp, pn_var); compile_node(comp, pn_step); EMIT_ARG(binary_op, MP_BINARY_OP_INPLACE_ADD); - c_assign(comp, pn_var, ASSIGN_AUG_STORE); + EMIT(dup_top); EMIT_ARG(label_assign, entry_label); // compile: if var <cond> end: goto top - compile_node(comp, pn_var); compile_node(comp, pn_end); assert(MP_PARSE_NODE_IS_SMALL_INT(pn_step)); if (MP_PARSE_NODE_LEAF_SMALL_INT(pn_step) >= 0) { @@ -1572,6 +1578,9 @@ void compile_for_stmt_optimised_range(compiler_t *comp, mp_parse_node_t pn_var, } EMIT_ARG(pop_jump_if_true, top_label); + // discard final value of var that failed the loop condition + EMIT(pop_top); + // break/continue apply to outer loop (if any) in the else block END_BREAK_CONTINUE_BLOCK @@ -10,6 +10,10 @@ #define ROUND_ALLOC(a) (((a) & ((~0) - 7)) + 8) void vstr_init(vstr_t *vstr, int alloc) { + if (alloc < 2) { + // need at least 1 byte for the null byte at the end + alloc = 2; + } vstr->alloc = alloc; vstr->len = 0; vstr->buf = m_new(char, vstr->alloc); |