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vm: Don't unconditionally allocate state on stack, do that only if needed.

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This makes sure that only as much stack allocated as actually used, reducing
stack usage for each Python function call.
This commit is contained in:
Paul Sokolovsky 2014-05-31 03:41:08 +03:00
parent ff8da0b835
commit b16523aa95
1 changed files with 7 additions and 4 deletions
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11
py/vm.c
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@ -28,6 +28,7 @@
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <alloca.h>
#include "mpconfig.h"
#include "nlr.h"
@ -117,21 +118,23 @@ mp_vm_return_kind_t mp_execute_bytecode(const byte *code, const mp_obj_t *args,
ip += 4;
// allocate state for locals and stack
mp_obj_t temp_state[VM_MAX_STATE_ON_STACK];
mp_obj_t *state = &temp_state[0];
#if DETECT_VM_STACK_OVERFLOW
n_state += 1;
#endif
mp_obj_t *state;
if (n_state > VM_MAX_STATE_ON_STACK) {
state = m_new(mp_obj_t, n_state);
} else {
state = alloca(sizeof(mp_obj_t) * n_state);
}
mp_obj_t *sp = &state[0] - 1;
// allocate state for exceptions
mp_exc_stack_t exc_state[VM_MAX_EXC_STATE_ON_STACK];
mp_exc_stack_t *exc_stack = &exc_state[0];
mp_exc_stack_t *exc_stack;
if (n_exc_stack > VM_MAX_EXC_STATE_ON_STACK) {
exc_stack = m_new(mp_exc_stack_t, n_exc_stack);
} else {
exc_stack = alloca(sizeof(mp_exc_stack_t) * n_exc_stack);
}
mp_exc_stack_t *exc_sp = &exc_stack[0] - 1;