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py/nlr: Factor out common NLR code to macro and generic funcs in nlr.c.

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Each NLR implementation (Thumb, x86, x64, xtensa, setjmp) duplicates a lot
of the NLR code, specifically that dealing with pushing and popping the NLR
pointer to maintain the linked-list of NLR buffers.  This patch factors all
of that code out of the specific implementations into generic functions in
nlr.c, along with a helper macro in nlr.h.  This eliminates duplicated
code.
This commit is contained in:
Damien George
2017-12-28 16:46:30 +11:00
parent 5bf8e85fc8
commit b25f92160b
8 changed files with 76 additions and 103 deletions
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27
py/nlr.h
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@@ -88,24 +88,29 @@ struct _nlr_buf_t {
#define MP_NLR_RESTORE_PYSTACK(nlr_buf) (void)nlr_buf
#endif
#if MICROPY_NLR_SETJMP
#include "py/mpstate.h"
// Helper macro to use at the start of a specific nlr_jump implementation
#define MP_NLR_JUMP_HEAD(val, top) \
nlr_buf_t **_top_ptr = &MP_STATE_THREAD(nlr_top); \
nlr_buf_t *top = *_top_ptr; \
if (top == NULL) { \
nlr_jump_fail(val); \
} \
top->ret_val = val; \
MP_NLR_RESTORE_PYSTACK(top); \
*_top_ptr = top->prev; \
NORETURN void nlr_setjmp_jump(void *val);
#if MICROPY_NLR_SETJMP
// nlr_push() must be defined as a macro, because "The stack context will be
// invalidated if the function which called setjmp() returns."
#define nlr_push(buf) ( \
(buf)->prev = MP_STATE_THREAD(nlr_top), \
MP_NLR_SAVE_PYSTACK(buf), \
MP_STATE_THREAD(nlr_top) = (buf), \
setjmp((buf)->jmpbuf))
#define nlr_pop() { MP_STATE_THREAD(nlr_top) = MP_STATE_THREAD(nlr_top)->prev; }
#define nlr_jump(val) nlr_setjmp_jump(val)
// For this case it is safe to call nlr_push_tail() first.
#define nlr_push(buf) (nlr_push_tail(buf), setjmp((buf)->jmpbuf))
#else
unsigned int nlr_push(nlr_buf_t *);
#endif
unsigned int nlr_push_tail(nlr_buf_t *top);
void nlr_pop(void);
NORETURN void nlr_jump(void *val);
#endif
// This must be implemented by a port. It's called by nlr_jump
// if no nlr buf has been pushed. It must not return, but rather