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-rw-r--r--boehmgc-coroutine-sp-fallback.diff77
1 files changed, 77 insertions, 0 deletions
diff --git a/boehmgc-coroutine-sp-fallback.diff b/boehmgc-coroutine-sp-fallback.diff
new file mode 100644
index 000000000..8fdafbecb
--- /dev/null
+++ b/boehmgc-coroutine-sp-fallback.diff
@@ -0,0 +1,77 @@
+diff --git a/darwin_stop_world.c b/darwin_stop_world.c
+index 3dbaa3fb..36a1d1f7 100644
+--- a/darwin_stop_world.c
++++ b/darwin_stop_world.c
+@@ -352,6 +352,7 @@ GC_INNER void GC_push_all_stacks(void)
+ int nthreads = 0;
+ word total_size = 0;
+ mach_msg_type_number_t listcount = (mach_msg_type_number_t)THREAD_TABLE_SZ;
++ size_t stack_limit;
+ if (!EXPECT(GC_thr_initialized, TRUE))
+ GC_thr_init();
+
+@@ -407,6 +408,19 @@ GC_INNER void GC_push_all_stacks(void)
+ GC_push_all_stack_sections(lo, hi, p->traced_stack_sect);
+ }
+ if (altstack_lo) {
++ // When a thread goes into a coroutine, we lose its original sp until
++ // control flow returns to the thread.
++ // While in the coroutine, the sp points outside the thread stack,
++ // so we can detect this and push the entire thread stack instead,
++ // as an approximation.
++ // We assume that the coroutine has similarly added its entire stack.
++ // This could be made accurate by cooperating with the application
++ // via new functions and/or callbacks.
++ stack_limit = pthread_get_stacksize_np(p->id);
++ if (altstack_lo >= altstack_hi || altstack_lo < altstack_hi - stack_limit) { // sp outside stack
++ altstack_lo = altstack_hi - stack_limit;
++ }
++
+ total_size += altstack_hi - altstack_lo;
+ GC_push_all_stack(altstack_lo, altstack_hi);
+ }
+diff --git a/pthread_stop_world.c b/pthread_stop_world.c
+index 4b2c429..1fb4c52 100644
+--- a/pthread_stop_world.c
++++ b/pthread_stop_world.c
+@@ -673,6 +673,8 @@ GC_INNER void GC_push_all_stacks(void)
+ struct GC_traced_stack_sect_s *traced_stack_sect;
+ pthread_t self = pthread_self();
+ word total_size = 0;
++ size_t stack_limit;
++ pthread_attr_t pattr;
+
+ if (!EXPECT(GC_thr_initialized, TRUE))
+ GC_thr_init();
+@@ -722,6 +724,31 @@ GC_INNER void GC_push_all_stacks(void)
+ hi = p->altstack + p->altstack_size;
+ /* FIXME: Need to scan the normal stack too, but how ? */
+ /* FIXME: Assume stack grows down */
++ } else {
++ if (pthread_getattr_np(p->id, &pattr)) {
++ ABORT("GC_push_all_stacks: pthread_getattr_np failed!");
++ }
++ if (pthread_attr_getstacksize(&pattr, &stack_limit)) {
++ ABORT("GC_push_all_stacks: pthread_attr_getstacksize failed!");
++ }
++ if (pthread_attr_destroy(&pattr)) {
++ ABORT("GC_push_all_stacks: pthread_attr_destroy failed!");
++ }
++ // When a thread goes into a coroutine, we lose its original sp until
++ // control flow returns to the thread.
++ // While in the coroutine, the sp points outside the thread stack,
++ // so we can detect this and push the entire thread stack instead,
++ // as an approximation.
++ // We assume that the coroutine has similarly added its entire stack.
++ // This could be made accurate by cooperating with the application
++ // via new functions and/or callbacks.
++ #ifndef STACK_GROWS_UP
++ if (lo >= hi || lo < hi - stack_limit) { // sp outside stack
++ lo = hi - stack_limit;
++ }
++ #else
++ #error "STACK_GROWS_UP not supported in boost_coroutine2 (as of june 2021), so we don't support it in Nix."
++ #endif
+ }
+ GC_push_all_stack_sections(lo, hi, traced_stack_sect);
+ # ifdef STACK_GROWS_UP