From 5668de71107022a316ee967162bc16c10754b9ce Mon Sep 17 00:00:00 2001 From: "Brian J. Cardiff" Date: Mon, 6 May 2019 12:06:12 +0300 Subject: Add API functions to get and set the stack bottom of each thread Issue #277 (bdwgc). This API is useful to support coroutines. * include/gc.h (GC_get_my_stackbottom, GC_set_stackbottom): New API function declaration. * misc.c [!THREADS] (GC_set_stackbottom, GC_get_my_stackbottom): New function definition. * pthread_support.c [GC_PTHREADS && !GC_WIN32_THREADS] (GC_set_stackbottom, GC_get_my_stackbottom): Likewise. * win32_threads.c [GC_WIN32_THREADS] (GC_set_stackbottom, GC_get_my_stackbottom): Likewise. * tests/test.c (struct thr_hndl_sb_s): Define. * tests/test.c (set_stackbottom): New function (which calls GC_set_stackbottom). * tests/test.c (run_one_test): Define thr_hndl_sb local variable; call GC_get_my_stackbottom() and set_stackbottom(). * win32_threads.c [GC_WIN32_THREADS && I386] (struct GC_Thread_Rep): Add initial_stack_base field. * win32_threads.c [GC_WIN32_THREADS && I386] (GC_record_stack_base, GC_call_with_gc_active): Set initial_stack_base field. * win32_threads.c [GC_WIN32_THREADS && I386] (GC_push_stack_for): Handle the case when GetThreadContext() might return stale register values, thread stack_base != initial_stack_base but the stack is not inside the TIB stack (use context.Esp but call WARN); add TODO. --- win32_threads.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 73 insertions(+), 1 deletion(-) (limited to 'win32_threads.c') diff --git a/win32_threads.c b/win32_threads.c index 2e9f37fb..f45e8c04 100644 --- a/win32_threads.c +++ b/win32_threads.c @@ -214,6 +214,11 @@ struct GC_Thread_Rep { # ifdef IA64 ptr_t backing_store_end; ptr_t backing_store_ptr; +# elif defined(I386) + ptr_t initial_stack_base; + /* The cold end of the stack saved by */ + /* GC_record_stack_base (never modified */ + /* by GC_set_stackbottom). */ # endif ptr_t thread_blocked_sp; /* Protected by GC lock. */ @@ -374,6 +379,8 @@ GC_INLINE void GC_record_stack_base(GC_vthread me, me -> stack_base = (ptr_t)sb->mem_base; # ifdef IA64 me -> backing_store_end = (ptr_t)sb->reg_base; +# elif defined(I386) + me -> initial_stack_base = (ptr_t)sb->mem_base; # endif if (me -> stack_base == NULL) ABORT("Bad stack base in GC_register_my_thread"); @@ -913,8 +920,12 @@ GC_API void * GC_CALL GC_call_with_gc_active(GC_fn_type fn, /* Adjust our stack bottom pointer (this could happen unless */ /* GC_get_stack_base() was used which returned GC_SUCCESS). */ GC_ASSERT(me -> stack_base != NULL); - if ((word)me->stack_base < (word)(&stacksect)) + if ((word)me->stack_base < (word)(&stacksect)) { me -> stack_base = (ptr_t)(&stacksect); +# if defined(I386) + me -> initial_stack_base = me -> stack_base; +# endif + } if (me -> thread_blocked_sp == NULL) { /* We are not inside GC_do_blocking() - do nothing more. */ @@ -958,6 +969,53 @@ GC_API void * GC_CALL GC_call_with_gc_active(GC_fn_type fn, return client_data; /* result */ } +GC_API void GC_CALL GC_set_stackbottom(void *gc_thread_handle, + const struct GC_stack_base *sb) +{ + GC_thread t = (GC_thread)gc_thread_handle; + + GC_ASSERT(sb -> mem_base != NULL); + if (!EXPECT(GC_is_initialized, TRUE)) { + GC_ASSERT(NULL == t); + GC_stackbottom = (char *)sb->mem_base; +# ifdef IA64 + GC_register_stackbottom = (ptr_t)sb->reg_base; +# endif + return; + } + + GC_ASSERT(I_HOLD_LOCK()); + if (NULL == t) { /* current thread? */ + t = GC_lookup_thread_inner(GetCurrentThreadId()); + CHECK_LOOKUP_MY_THREAD(t); + } + GC_ASSERT(!KNOWN_FINISHED(t)); + GC_ASSERT(NULL == t -> thread_blocked_sp + && NULL == t -> traced_stack_sect); /* for now */ + t -> stack_base = (ptr_t)sb->mem_base; + t -> last_stack_min = ADDR_LIMIT; /* reset the known minimum */ +# ifdef IA64 + t -> backing_store_end = (ptr_t)sb->reg_base; +# endif +} + +GC_API void * GC_CALL GC_get_my_stackbottom(struct GC_stack_base *sb) +{ + DWORD thread_id = GetCurrentThreadId(); + GC_thread me; + DCL_LOCK_STATE; + + LOCK(); + me = GC_lookup_thread_inner(thread_id); + CHECK_LOOKUP_MY_THREAD(me); /* the thread is assumed to be registered */ + sb -> mem_base = me -> stack_base; +# ifdef IA64 + sb -> reg_base = me -> backing_store_end; +# endif + UNLOCK(); + return (void *)me; /* gc_thread_handle */ +} + #ifdef GC_PTHREADS /* A quick-and-dirty cache of the mapping between pthread_t */ @@ -1454,6 +1512,20 @@ STATIC word GC_push_stack_for(GC_thread thread, DWORD me) # endif GC_ASSERT(!((word)thread->stack_base COOLER_THAN (word)tib->StackBase)); + if (thread->stack_base != thread->initial_stack_base) { + /* We are in a coroutine. */ + if ((word)thread->stack_base <= (word)sp /* StackLimit */ + || (word)tib->StackBase < (word)thread->stack_base) { + /* The coroutine stack is not within TIB stack. */ + sp = (ptr_t)context.Esp; + WARN("GetThreadContext might return stale register values" + " including ESP=%p\n", sp); + /* TODO: Because of WoW64 bug, there is no guarantee that */ + /* sp really points to the stack top but, for now, we do */ + /* our best as the TIB stack limit/base cannot be used */ + /* while we are inside a coroutine. */ + } + } } else { # ifdef DEBUG_THREADS { -- cgit v1.2.1