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py/nlrthumb: Fix use of naked funcs, must only contain basic asm code.
A function with a naked attribute must only contain basic inline asm statements and no C code. For nlr_push this means removing the "return 0" statement. But for some gcc versions this induces a compiler warning so the __builtin_unreachable() line needs to be added. For nlr_jump, this function contains a combination of C code and inline asm so cannot be naked.
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Lines changed: 9 additions & 2 deletions

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‎py/nlrthumb.c‎

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -76,7 +76,10 @@ __attribute__((naked)) unsigned int nlr_push(nlr_buf_t *nlr) {
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#endif
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);
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return 0; // needed to silence compiler warning
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#if defined(__GNUC__)
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// Older versions of gcc give an error when naked functions don't return a value
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__builtin_unreachable();
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#endif
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}
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__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr) {
@@ -92,7 +95,7 @@ void nlr_pop(void) {
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*top = (*top)->prev;
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}
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NORETURN __attribute__((naked)) void nlr_jump(void *val) {
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NORETURN void nlr_jump(void *val) {
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nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
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nlr_buf_t *top = *top_ptr;
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if (top == NULL) {
@@ -138,7 +141,11 @@ NORETURN __attribute__((naked)) void nlr_jump(void *val) {
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: // clobbered registers
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);
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#if defined(__GNUC__)
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__builtin_unreachable();
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#else
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for (;;); // needed to silence compiler warning
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#endif
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}
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#endif // (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))

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