From a01207c473dcab88eb0ac769d2d9c68d7c9e0588 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <iant@google.com>
Date: Mon, 28 Nov 2011 05:44:31 +0000
Subject: [PATCH] generic-morestack.c (__splitstack_find): Check for NULL old
stack value.
* generic-morestack.c (__splitstack_find): Check for NULL old
stack value.
(__splitstack_resetcontext): New function.
(__splitstack_releasecontext): New function.
* libgcc-std.ver.in: Add new functions to GCC_4.7.0.
From-SVN: r181771
---
libgcc/ChangeLog | 8 ++++
libgcc/generic-morestack.c | 76 ++++++++++++++++++++++++++++++++++++--
libgcc/libgcc-std.ver.in | 2 +
3 files changed, 83 insertions(+), 3 deletions(-)
diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 4217f323cf7f..4b244f41022c 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,11 @@
+2011-11-27 Ian Lance Taylor <iant@google.com>
+
+ * generic-morestack.c (__splitstack_find): Check for NULL old
+ stack value.
+ (__splitstack_resetcontext): New function.
+ (__splitstack_releasecontext): New function.
+ * libgcc-std.ver.in: Add new functions to GCC_4.7.0.
+
2011-11-27 Iain Sandoe <iains@gcc.gnu.org>
* config/darwin-crt-tm.c: Correct comments, use correct licence.
diff --git a/libgcc/generic-morestack.c b/libgcc/generic-morestack.c
index 00a3b1c3bf06..4dbaa0e4cdc9 100644
--- a/libgcc/generic-morestack.c
+++ b/libgcc/generic-morestack.c
@@ -115,6 +115,14 @@ extern void *
__splitstack_makecontext (size_t, void *context[10], size_t *)
__attribute__ ((visibility ("default")));
+extern void *
+__splitstack_resetcontext (void *context[10], size_t *)
+ __attribute__ ((visibility ("default")));
+
+extern void
+__splitstack_releasecontext (void *context[10])
+ __attribute__ ((visibility ("default")));
+
extern void
__splitstack_block_signals_context (void *context[10], int *, int *)
__attribute__ ((visibility ("default")));
@@ -911,15 +919,23 @@ __splitstack_find (void *segment_arg, void *sp, size_t *len,
nsp = (char *) segment->old_stack;
+ if (nsp == NULL)
+ {
+ /* We've reached the top of the stack. */
+ *next_segment = (void *) (uintptr_type) 2;
+ }
+ else
+ {
#if defined (__x86_64__)
- nsp -= 12 * sizeof (void *);
+ nsp -= 12 * sizeof (void *);
#elif defined (__i386__)
- nsp -= 6 * sizeof (void *);
+ nsp -= 6 * sizeof (void *);
#else
#error "unrecognized target"
#endif
- *next_sp = (void *) nsp;
+ *next_sp = (void *) nsp;
+ }
#ifdef STACK_GROWS_DOWNWARD
*len = (char *) (segment + 1) + segment->size - (char *) sp;
@@ -1037,6 +1053,60 @@ __splitstack_makecontext (size_t stack_size, void *context[NUMBER_OFFSETS],
return (void *) (segment + 1);
}
+/* Given an existing split stack context, reset it back to the start
+ of the stack. Return the stack pointer and size, appropriate for
+ use with makecontext. This may be used if a coroutine exits, in
+ order to reuse the stack segments for a new coroutine. */
+
+void *
+__splitstack_resetcontext (void *context[10], size_t *size)
+{
+ struct stack_segment *segment;
+ void *initial_sp;
+ size_t initial_size;
+ void *ret;
+
+ /* Reset the context assuming that MORESTACK_SEGMENTS, INITIAL_SP
+ and INITIAL_SP_LEN are correct. */
+
+ segment = context[MORESTACK_SEGMENTS];
+ context[CURRENT_SEGMENT] = segment;
+ context[CURRENT_STACK] = NULL;
+ if (segment == NULL)
+ {
+ initial_sp = context[INITIAL_SP];
+ initial_size = (uintptr_type) context[INITIAL_SP_LEN];
+ ret = initial_sp;
+#ifdef STACK_GROWS_DOWNWARD
+ ret = (void *) ((char *) ret - initial_size);
+#endif
+ }
+ else
+ {
+#ifdef STACK_GROWS_DOWNWARD
+ initial_sp = (void *) ((char *) (segment + 1) + segment->size);
+#else
+ initial_sp = (void *) (segment + 1);
+#endif
+ initial_size = segment->size;
+ ret = (void *) (segment + 1);
+ }
+ context[STACK_GUARD] = __morestack_make_guard (initial_sp, initial_size);
+ context[BLOCK_SIGNALS] = NULL;
+ *size = initial_size;
+ return ret;
+}
+
+/* Release all the memory associated with a splitstack context. This
+ may be used if a coroutine exits and the associated stack should be
+ freed. */
+
+void
+__splitstack_releasecontext (void *context[10])
+{
+ __morestack_release_segments (context[MORESTACK_SEGMENTS], 1);
+}
+
/* Like __splitstack_block_signals, but operating on CONTEXT, rather
than on the current state. */
diff --git a/libgcc/libgcc-std.ver.in b/libgcc/libgcc-std.ver.in
index 2d66612d1c56..ec702952f9b9 100644
--- a/libgcc/libgcc-std.ver.in
+++ b/libgcc/libgcc-std.ver.in
@@ -1932,4 +1932,6 @@ GCC_4.7.0 {
__splitstack_makecontext
__splitstack_block_signals_context
__splitstack_find_context
+ __splitstack_resetcontext
+ __splitstack_releasecontext
}
--
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