[gcc r14-9620] handle unwind tables that are embedded within unwinding code [PR111731]
https://gcc.gnu.org/g:a364148530c28645ce87adbc58a66c9f32a325ab
commit r14-9620-ga364148530c28645ce87adbc58a66c9f32a325ab
Author: Thomas Neumann
Date: Mon Mar 11 14:35:20 2024 +0100
handle unwind tables that are embedded within unwinding code [PR111731]
Original bug report: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111731
The unwinding mechanism registers both the code range and the unwind
table itself within a b-tree lookup structure. That data structure
assumes that is consists of non-overlappping intervals. This
becomes a problem if the unwinding table is embedded within the
code itself, as now the intervals do overlap.
To fix this problem we now keep the unwind tables in a separate
b-tree, which prevents the overlap.
libgcc/ChangeLog:
PR libgcc/111731
* unwind-dw2-fde.c: Split unwind ranges if they contain the
unwind table.
Diff:
---
libgcc/unwind-dw2-fde.c | 37 +
1 file changed, 21 insertions(+), 16 deletions(-)
diff --git a/libgcc/unwind-dw2-fde.c b/libgcc/unwind-dw2-fde.c
index 61a578d097e..9d503545677 100644
--- a/libgcc/unwind-dw2-fde.c
+++ b/libgcc/unwind-dw2-fde.c
@@ -48,6 +48,7 @@ typedef __UINTPTR_TYPE__ uintptr_type;
#include "unwind-dw2-btree.h"
static struct btree registered_frames;
+static struct btree registered_objects;
static bool in_shutdown;
static void
@@ -58,6 +59,7 @@ release_registered_frames (void)
/* Release the b-tree and all frames. Frame releases that happen later are
* silently ignored */
btree_destroy (®istered_frames);
+ btree_destroy (®istered_objects);
in_shutdown = true;
}
@@ -103,6 +105,21 @@ static __gthread_mutex_t object_mutex;
#endif
#endif
+#ifdef ATOMIC_FDE_FAST_PATH
+// Register the pc range for a given object in the lookup structure.
+static void
+register_pc_range_for_object (uintptr_type begin, struct object *ob)
+{
+ // Register the object itself to know the base pointer on deregistration.
+ btree_insert (®istered_objects, begin, 1, ob);
+
+ // Register the frame in the b-tree
+ uintptr_type range[2];
+ get_pc_range (ob, range);
+ btree_insert (®istered_frames, range[0], range[1] - range[0], ob);
+}
+#endif
+
/* Called from crtbegin.o to register the unwind info for an object. */
void
@@ -124,13 +141,7 @@ __register_frame_info_bases (const void *begin, struct
object *ob,
#endif
#ifdef ATOMIC_FDE_FAST_PATH
- // Register the object itself to know the base pointer on deregistration.
- btree_insert (®istered_frames, (uintptr_type) begin, 1, ob);
-
- // Register the frame in the b-tree
- uintptr_type range[2];
- get_pc_range (ob, range);
- btree_insert (®istered_frames, range[0], range[1] - range[0], ob);
+ register_pc_range_for_object ((uintptr_type) begin, ob);
#else
init_object_mutex_once ();
__gthread_mutex_lock (&object_mutex);
@@ -178,13 +189,7 @@ __register_frame_info_table_bases (void *begin, struct
object *ob,
ob->s.b.encoding = DW_EH_PE_omit;
#ifdef ATOMIC_FDE_FAST_PATH
- // Register the object itself to know the base pointer on deregistration.
- btree_insert (®istered_frames, (uintptr_type) begin, 1, ob);
-
- // Register the frame in the b-tree
- uintptr_type range[2];
- get_pc_range (ob, range);
- btree_insert (®istered_frames, range[0], range[1] - range[0], ob);
+ register_pc_range_for_object ((uintptr_type) begin, ob);
#else
init_object_mutex_once ();
__gthread_mutex_lock (&object_mutex);
@@ -232,7 +237,7 @@ __deregister_frame_info_bases (const void *begin)
#ifdef ATOMIC_FDE_FAST_PATH
// Find the originally registered object to get the base pointer.
- ob = btree_remove (®istered_frames, (uintptr_type) begin);
+ ob = btree_remove (®istered_objects, (uintptr_type) begin);
// Remove the corresponding PC range.
if (ob)
@@ -240,7 +245,7 @@ __deregister_frame_info_bases (const void *begin)
uintptr_type range[2];
get_pc_range (ob, range);
if (range[0] != range[1])
-btree_remove (®istered_frames, range[0]);
+ btree_remove (®istered_frames, range[0]);
}
// Deallocate the sort array if any.
[gcc r13-8555] handle unwind tables that are embedded within unwinding code [PR111731]
https://gcc.gnu.org/g:11f37868bb5812c4f0ac023909f5421595f68a43
commit r13-8555-g11f37868bb5812c4f0ac023909f5421595f68a43
Author: Thomas Neumann
Date: Mon Mar 11 14:35:20 2024 +0100
handle unwind tables that are embedded within unwinding code [PR111731]
Original bug report: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111731
The unwinding mechanism registers both the code range and the unwind
table itself within a b-tree lookup structure. That data structure
assumes that is consists of non-overlappping intervals. This
becomes a problem if the unwinding table is embedded within the
code itself, as now the intervals do overlap.
To fix this problem we now keep the unwind tables in a separate
b-tree, which prevents the overlap.
libgcc/ChangeLog:
PR libgcc/111731
* unwind-dw2-fde.c: Split unwind ranges if they contain the
unwind table.
Diff:
---
libgcc/unwind-dw2-fde.c | 37 +
1 file changed, 21 insertions(+), 16 deletions(-)
diff --git a/libgcc/unwind-dw2-fde.c b/libgcc/unwind-dw2-fde.c
index 51129906fac..6a54450253f 100644
--- a/libgcc/unwind-dw2-fde.c
+++ b/libgcc/unwind-dw2-fde.c
@@ -48,6 +48,7 @@ typedef __UINTPTR_TYPE__ uintptr_type;
#include "unwind-dw2-btree.h"
static struct btree registered_frames;
+static struct btree registered_objects;
static bool in_shutdown;
static void
@@ -58,6 +59,7 @@ release_registered_frames (void)
/* Release the b-tree and all frames. Frame releases that happen later are
* silently ignored */
btree_destroy (®istered_frames);
+ btree_destroy (®istered_objects);
in_shutdown = true;
}
@@ -103,6 +105,21 @@ static __gthread_mutex_t object_mutex;
#endif
#endif
+#ifdef ATOMIC_FDE_FAST_PATH
+// Register the pc range for a given object in the lookup structure.
+static void
+register_pc_range_for_object (uintptr_type begin, struct object *ob)
+{
+ // Register the object itself to know the base pointer on deregistration.
+ btree_insert (®istered_objects, begin, 1, ob);
+
+ // Register the frame in the b-tree
+ uintptr_type range[2];
+ get_pc_range (ob, range);
+ btree_insert (®istered_frames, range[0], range[1] - range[0], ob);
+}
+#endif
+
/* Called from crtbegin.o to register the unwind info for an object. */
void
@@ -124,13 +141,7 @@ __register_frame_info_bases (const void *begin, struct
object *ob,
#endif
#ifdef ATOMIC_FDE_FAST_PATH
- // Register the object itself to know the base pointer on deregistration.
- btree_insert (®istered_frames, (uintptr_type) begin, 1, ob);
-
- // Register the frame in the b-tree
- uintptr_type range[2];
- get_pc_range (ob, range);
- btree_insert (®istered_frames, range[0], range[1] - range[0], ob);
+ register_pc_range_for_object ((uintptr_type) begin, ob);
#else
init_object_mutex_once ();
__gthread_mutex_lock (&object_mutex);
@@ -178,13 +189,7 @@ __register_frame_info_table_bases (void *begin, struct
object *ob,
ob->s.b.encoding = DW_EH_PE_omit;
#ifdef ATOMIC_FDE_FAST_PATH
- // Register the object itself to know the base pointer on deregistration.
- btree_insert (®istered_frames, (uintptr_type) begin, 1, ob);
-
- // Register the frame in the b-tree
- uintptr_type range[2];
- get_pc_range (ob, range);
- btree_insert (®istered_frames, range[0], range[1] - range[0], ob);
+ register_pc_range_for_object ((uintptr_type) begin, ob);
#else
init_object_mutex_once ();
__gthread_mutex_lock (&object_mutex);
@@ -232,7 +237,7 @@ __deregister_frame_info_bases (const void *begin)
#ifdef ATOMIC_FDE_FAST_PATH
// Find the originally registered object to get the base pointer.
- ob = btree_remove (®istered_frames, (uintptr_type) begin);
+ ob = btree_remove (®istered_objects, (uintptr_type) begin);
// Remove the corresponding PC range.
if (ob)
@@ -240,7 +245,7 @@ __deregister_frame_info_bases (const void *begin)
uintptr_type range[2];
get_pc_range (ob, range);
if (range[0] != range[1])
-btree_remove (®istered_frames, range[0]);
+ btree_remove (®istered_frames, range[0]);
}
// Deallocate the sort array if any.
