Thu Dec 11 20:42:18 1997 Teemu Torma <tot@trema.com>

	Thread-safe EH support for pthreads, DCE threads and Solaris threads.

	* integrate.c (expand_inline_function): If the inline fn uses eh
	context, make sure that the current fn has one.
	* toplev.c (rest_of_compilation): Call emit_eh_context.
	* except.c (use_eh_context): New fn.
	(get_eh_context_once): New fn.
	(call_get_eh_context): New fn.
	(emit_eh_context): New fn.
	(get_eh_context): Call either get_eh_context_once or
	call_get_eh_context, depending on what we have.
	(get_dynamic_handler_chain): Call get_eh_context_once.
	* except.h: Prototypes for fns above.
	* optabs.c (get_eh_context_libfunc): Removed.
	(init_optabs): Don't initialize it.
	* expr.h (get_eh_context_libfunc): Removed.
	* rtl.h, rtl.c: New reg_note REG_EH_CONTEXT.
	* config/pa/pa.h (CPP_SPEC): Support for -threads.
	* config/pa/pa-hpux10.h (LIB_SPEC): Ditto.
	* config/pa/t-pa (MULTILIB_OPTIONS, MULTILIB_DIRNAMES):
	New multilib for -threads.
	* config/sparc/t-sol2: Added multilibs for -threads and
	made -pthreads alias to it.
	* config/sparc/sol2.h (CPP_SPEC, LIB_SPEC):
	Added -threads and -pthreads options.
	* libgcc-thr.h: New file.
	* libgcc2.c: (__get_cpp_eh_context): Removed.
	(struct cpp_eh_context): Removed.
	(struct eh_context): Replaced cpp_eh_context with generic language
	specific pointer.
	(__get_eh_info): New function.
	(__throw): Check eh_context::info.
	(__sjthrow): Ditto.
	* libgcc2.c: Include libgcc-thr.h.
	(new_eh_context, __get_eh_context,
	eh_pthread_initialize, eh_context_initialize, eh_context_static,
	eh_context_specific, eh_context_free): New functions.
	(get_eh_context, eh_context_key): New variables.
	(__sjthrow, __sjpopnthrow, __eh_pcnthrow, __throw): Use
	get_eh_context to get the context.
	(longjmp): Move the declaration inside
	#ifdef DONT_USE_BUILTIN_SETJMP.
	* frame.c: Include libgcc-thr.h.
	(object_mutex): Mutex to protect the object list.
	(find_fde, __register_frame, __register_frame_table,
	__deregister_frame): Hold the lock while accessing objects.
	* except.h (get_eh_context): Declare.
	* except.c (current_function_ehc): Define.
	(current_function_dhc, current_function_dcc): Removed.
	(get_eh_context): New function.
	(get_dynamic_handler_chain): Use get_eh_context.
	(get_saved_pc_ref): Ditto.
	(get_dynamic_cleanup_chain): Removed references to
	current_function_dcc.
	(save_eh_status, restore_eh_status): Save and restore
	current_function_ehc instead.
	* optabs.c (get_eh_context_libfunc): New variable.
	(init_optabs): Initialize it.
	* expr.h: Declare get_eh_context_libfunc.
	* function.h (struct function): Replaced dhc and dcc with ehc.
	* except.c (get_saved_pc_ref): New functions.
	(eh_saved_pc_rtx, eh_saved_pc): Deleted.
	(expand_internal_throw_indirect): Use get_saved_pc_ref() instead
	of eh_saved_pc.
	(end_eh_unwinder): Likewise.
	(init_eh): Remove initialization of eh_saved_pc.
	* optabs.c (get_saved_pc_libfunc): New variable.
	(init_optabs): Initialize it.
	* expr.h: Declare get_saved_pc_libfunc.
	* except.h (eh_saved_pc_rtx): Deleted.
	(get_saved_pc_ref): Declared.

	From Scott Snyder <snyder@d0sgif.fnal.gov>:
	* libgcc2.c (__get_saved_pc): New.
	(__eh_type, __eh_pc): Deleted.
	(__eh_pcnthrow): Use __get_saved_pc() instead of __eh_pc.
	(__get_dynamic_handler_chain): Move __dynamic_handler_chain inside
	this fcn.

cp/:
Thu Dec 11 20:43:33 1997  Teemu Torma  <tot@trema.com>

	* decl.c (ptr_ptr_type_node): Define.
	(init_decl_processing): Initialize it.
	* cp-tree.h: Declare it.
	* exception.cc (__cp_exception_info): Use __get_eh_info.
	(__cp_push_exception): Ditto.
	(__cp_pop_exception): Ditto.

	From Scott Snyder <snyder@d0sgif.fnal.gov>:
        * except.c (expand_builtin_throw): Use get_saved_pc_ref instead of
	saved_pc.
	(init_exception_processing): Removed saved_pc initialization.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@17052 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 176 insertions, 30 deletions

diff --git a/gcc/libgcc2.c b/gcc/libgcc2.c
index ad51863e912..1ad63013a15 100644
--- a/gcc/libgcc2.c
+++ b/gcc/libgcc2.c
@@ -2962,11 +2962,9 @@ int _exit_dummy_decl = 0;	/* prevent compiler & linker warnings */
 
 #ifdef L_eh
 
-/* Shared exception handling support routines.  */
+#include "libgcc-thr.h"
 
-/* Language-specific information about the active exception(s).  If there
-   are no active exceptions, it is set to 0.  */
-void *__eh_info;
+/* Shared exception handling support routines.  */
 
 void
 __default_terminate ()
@@ -2999,41 +2997,190 @@ __empty ()
 {
 }
 
+/* EH context structure. */
+
+struct eh_context
+{
+  void **dynamic_handler_chain;
+  void *saved_pc;
+#ifndef DWARF2_UNWIND_INFO
+  void *buf[2];
+#endif
+  /* This is language dependent part of the eh context. */
+  void *info;
+};
+
+/* This is a safeguard for dynamic handler chain. */
+
+static void *top_elt[2];
+
+/* Allocate and return a new EH context structure. */
+
+extern void __throw ();
+
+static void *
+new_eh_context ()
+{
+  struct eh_context *eh = (struct eh_context *) malloc (sizeof *eh);
+  if (! eh)
+    __terminate ();
+
+  memset (eh, 0, sizeof *eh);
+
+  eh->dynamic_handler_chain = top_elt;
+#ifndef DWARF2_UNWIND_INFO
+  eh->buf[0] = &eh->saved_pc;
+  eh->buf[1] = &__throw;
+#endif  
+
+  return eh;
+}
+
+#if __GTHREADS
+static __gthread_key_t eh_context_key;
+
+/* Destructor for struct eh_context. */
+static void
+eh_context_free (void *ptr)
+{
+  if (ptr)
+    free (ptr);
+}
+#endif
+
+/* Pointer to function to return EH context. */
+
+static struct eh_context *eh_context_initialize ();
+static struct eh_context *eh_context_static ();
+#if __GTHREADS
+static struct eh_context *eh_context_specific ();
+#endif
+
+static struct eh_context *(*get_eh_context) () = &eh_context_initialize;
+
+/* Routine to get EH context.
+   This one will simply call the function pointer. */
+
+void *
+__get_eh_context ()
+{
+  return (void *) (*get_eh_context) ();
+}
+
+/* Get and set the language specific info pointer. */
+
+void **
+__get_eh_info ()
+{
+  struct eh_context *eh = (*get_eh_context) ();
+  return (void **) &eh->info;
+}
+
+#if __GTHREADS
+static void
+eh_threads_initialize ()
+{
+  /* Try to create the key.  If it fails, revert to static method,
+     otherwise start using thread specific EH contexts. */
+  if (__gthread_key_create (&eh_context_key, &eh_context_free) == 0)
+    get_eh_context = &eh_context_specific;
+  else
+    get_eh_context = &eh_context_static;
+}
+#endif /* no __GTHREADS */
+
+/* Initialize EH context.
+   This will be called only once, since we change GET_EH_CONTEXT
+   pointer to another routine. */
+
+static struct eh_context *
+eh_context_initialize ()
+{
+#if __GTHREADS
+
+  static __gthread_once_t once = __GTHREAD_ONCE_INIT;
+  __gthread_once (&once, eh_threads_initialize);
+
+#else /* no __GTHREADS */
+
+  /* Use static version of EH context. */
+  get_eh_context = &eh_context_static;
+
+#endif /* no __GTHREADS */
+
+  return (*get_eh_context) ();
+}
+
+/* Return a static EH context. */
+
+static struct eh_context *
+eh_context_static ()
+{
+  static struct eh_context *eh;
+  if (! eh)
+    eh = new_eh_context ();
+  return eh;
+}
+
+#if __GTHREADS
+/* Return a thread specific EH context. */
+
+static struct eh_context *
+eh_context_specific ()
+{
+  struct eh_context *eh;
+  eh = (struct eh_context *) __gthread_getspecific (eh_context_key);
+  if (! eh)
+    {
+      eh = new_eh_context ();
+      if (__gthread_setspecific (eh_context_key, (void *) eh) != 0)
+	__terminate ();
+    }
+
+  return eh;
+}
+#endif __GTHREADS
+
 /* Support routines for setjmp/longjmp exception handling.  */
 
 /* Calls to __sjthrow are generated by the compiler when an exception
    is raised when using the setjmp/longjmp exception handling codegen
    method.  */
 
+#ifdef DONT_USE_BUILTIN_SETJMP
 extern void longjmp (void *, int);
-
-static void *top_elt[2];
-void **__dynamic_handler_chain = top_elt;
+#endif
 
 /* Routine to get the head of the current thread's dynamic handler chain
-   use for exception handling.
-
-   TODO: make thread safe.  */
+   use for exception handling. */
 
 void ***
 __get_dynamic_handler_chain ()
 {
-  return &__dynamic_handler_chain;
+  struct eh_context *eh = (*get_eh_context) ();
+  return (void ***) &eh->dynamic_handler_chain;
+}
+
+void **
+__get_saved_pc ()
+{
+  struct eh_context *eh = (*get_eh_context) ();
+  return (void **) &eh->saved_pc;
 }
 
 /* This is used to throw an exception when the setjmp/longjmp codegen
    method is used for exception handling.
 
-   We call __terminate if there are no handlers left (we know this
-   when the dynamic handler chain is top_elt).  Otherwise we run the
-   cleanup actions off the dynamic cleanup stack, and pop the top of
-   the dynamic handler chain, and use longjmp to transfer back to the
-   associated handler.  */
+   We call __terminate if there are no handlers left.  Otherwise we run the
+   cleanup actions off the dynamic cleanup stack, and pop the top of the
+   dynamic handler chain, and use longjmp to transfer back to the associated
+   handler.  */
 
 void
 __sjthrow ()
 {
-  void ***dhc = __get_dynamic_handler_chain ();
+  struct eh_context *eh = (*get_eh_context) ();
+  void ***dhc = &eh->dynamic_handler_chain;
   void *jmpbuf;
   void (*func)(void *, int);
   void *arg;
@@ -3081,7 +3228,7 @@ __sjthrow ()
   /* We must call terminate if we try and rethrow an exception, when
      there is no exception currently active and when there are no
      handlers left.  */
-  if (! __eh_info || (*dhc) == top_elt)
+  if (! eh->info || (*dhc) == top_elt)
     __terminate ();
     
   /* Find the jmpbuf associated with the top element of the dynamic
@@ -3108,7 +3255,8 @@ __sjthrow ()
 void
 __sjpopnthrow ()
 {
-  void ***dhc = __get_dynamic_handler_chain ();
+  struct eh_context *eh = (*get_eh_context) ();
+  void ***dhc = &eh->dynamic_handler_chain;
   void *jmpbuf;
   void (*func)(void *, int);
   void *arg;
@@ -3288,11 +3436,8 @@ __throw ()
 /* See expand_builtin_throw for details.  */
 
 void **__eh_pcnthrow () {
-  static void *buf[2] = {
-    &__eh_pc,
-    &__throw
-  };
-  return buf;
+  struct eh_context *eh = (*get_eh_context) ();
+  return &eh->buf[0];
 }
 
 #if #machine(i386)
@@ -3499,7 +3644,8 @@ in_reg_window (int reg, frame_state *udata)
 void
 __throw ()
 {
-  void *pc, *handler, *retaddr, *__eh_pc;
+  struct eh_context *eh = (*get_eh_context) ();
+  void *saved_pc, *pc, *handler, *retaddr;
   frame_state ustruct, ustruct2;
   frame_state *udata = &ustruct;
   frame_state *sub_udata = &ustruct2;
@@ -3509,7 +3655,7 @@ __throw ()
   /* This is required for C++ semantics.  We must call terminate if we
      try and rethrow an exception, when there is no exception currently
      active.  */
-  if (! __eh_info)
+  if (! eh->info)
     __terminate ();
     
   /* Start at our stack frame.  */
@@ -3534,8 +3680,8 @@ label:
   __builtin_unwind_init ();
 
   /* Now reset pc to the right throw point.  */
-  __eh_pc = __builtin_extract_return_addr (__builtin_return_address (0)) - 1;
-  pc = __eh_pc;
+  pc = __builtin_extract_return_addr (__builtin_return_address (0)) - 1;
+  saved_pc = pc;
 
   handler = 0;
   for (;;)
@@ -3567,7 +3713,7 @@ label:
   if (! handler)
     __terminate ();
 
-  if (pc == __eh_pc)
+  if (pc == saved_pc)
     /* We found a handler in the throw context, no need to unwind.  */
     udata = my_udata;
   else
@@ -3582,7 +3728,7 @@ label:
       void *handler_pc = pc;
 
       /* Start from the throw context again.  */
-      pc = __eh_pc;
+      pc = saved_pc;
       memcpy (udata, my_udata, sizeof (*udata));
 
       while (pc != handler_pc)