[2/3] arc: Add evaluation of long jump targets
Commit Message
Standard get_longjmp_target implementation, similar to what is in arm-tdep.c.
Actual value of jb_pc should be set in init_osabi methods of particular OS/ABI
implementations.
gdb/ChangeLog:
* arc-tdep.h (gdbarch_tdep): Add jb_pc.
* arc-tdep.c (arc_get_longjmp_target): New function.
(arc_gdbarch_init): Set get_longjmp_target if jb_pc is non-negative.
(arc_dump_tdep): Print jb_pc.
---
gdb/arc-tdep.c | 36 +++++++++++++++++++++++++++++++++++-
gdb/arc-tdep.h | 3 +++
2 files changed, 38 insertions(+), 1 deletion(-)
Comments
Anton Kolesov <Anton.Kolesov@synopsys.com> writes:
> Standard get_longjmp_target implementation, similar to what is in arm-tdep.c.
> Actual value of jb_pc should be set in init_osabi methods of particular OS/ABI
> implementations.
>
Patch is good to me, two nits below,
> gdb/ChangeLog:
>
> * arc-tdep.h (gdbarch_tdep): Add jb_pc.
* arc-tdep.h (struct gdbarch_tdep) <jb_pc>: New field.
> * arc-tdep.c (arc_get_longjmp_target): New function.
> (arc_gdbarch_init): Set get_longjmp_target if jb_pc is non-negative.
> (arc_dump_tdep): Print jb_pc.
> ---
> gdb/arc-tdep.c | 36 +++++++++++++++++++++++++++++++++++-
> gdb/arc-tdep.h | 3 +++
> 2 files changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/gdb/arc-tdep.c b/gdb/arc-tdep.c
> index 58de8e9..bc8bb98 100644
> --- a/gdb/arc-tdep.c
> +++ b/gdb/arc-tdep.c
> @@ -557,6 +557,34 @@ arc_store_return_value (struct gdbarch *gdbarch, struct type *type,
> error (_("arc_store_return_value: type length too large."));
> }
>
> +/* Implement the "get_longjmp_target" gdbarch method.
> +
> + Detemine the address the longjmp will jump to. We need to use the frame
> + info to get the register pointing to the jmp_buf, then extract the PC from
> + that. Since jmp_buf is the first argument to longjmp () it will be in r0.
> + Where we then go depends on the OS - OS/ABI initialization should set offset
> + from jmp_buf start to the stored PC location. */
> +
I don't see any extra information these comments have, so the first
sentence is enough, IMO.
/* Implement the "get_longjmp_target" gdbarch method. */
> +static int
> +arc_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
> +{
@@ -557,6 +557,34 @@ arc_store_return_value (struct gdbarch *gdbarch, struct type *type,
error (_("arc_store_return_value: type length too large."));
}
+/* Implement the "get_longjmp_target" gdbarch method.
+
+ Detemine the address the longjmp will jump to. We need to use the frame
+ info to get the register pointing to the jmp_buf, then extract the PC from
+ that. Since jmp_buf is the first argument to longjmp () it will be in r0.
+ Where we then go depends on the OS - OS/ABI initialization should set offset
+ from jmp_buf start to the stored PC location. */
+
+static int
+arc_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
+{
+ if (arc_debug)
+ debug_printf ("arc: get_longjmp_target\n");
+
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+ int pc_offset = tdep->jb_pc * ARC_REGISTER_SIZE;
+ gdb_byte buf[ARC_REGISTER_SIZE];
+ CORE_ADDR jb_addr = get_frame_register_unsigned (frame, ARC_FIRST_ARG_REGNUM);
+
+ if (target_read_memory (jb_addr + pc_offset, buf, ARC_REGISTER_SIZE))
+ return 0; /* Failed to read from memory. */
+
+ *pc = extract_unsigned_integer (buf, ARC_REGISTER_SIZE,
+ gdbarch_byte_order (gdbarch));
+ return 1;
+}
+
/* Implement the "return_value" gdbarch method. */
static enum return_value_convention
@@ -1162,6 +1190,7 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
/* Allocate the ARC-private target-dependent information structure, and the
GDB target-independent information structure. */
struct gdbarch_tdep *tdep = XCNEW (struct gdbarch_tdep);
+ tdep->jb_pc = -1; /* No longjmp support by default. */
struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
/* Data types. */
@@ -1246,6 +1275,9 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
It can override functions set earlier. */
gdbarch_init_osabi (info, gdbarch);
+ if (tdep->jb_pc >= 0)
+ set_gdbarch_get_longjmp_target (gdbarch, arc_get_longjmp_target);
+
tdesc_use_registers (gdbarch, tdesc, tdesc_data);
return gdbarch;
@@ -1256,7 +1288,9 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
static void
arc_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
{
- /* Empty for now. */
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ fprintf_unfiltered (file, "arc_dump_tdep: jb_pc = %i\n", tdep->jb_pc);
}
/* Suppress warning from -Wmissing-prototypes. */
@@ -81,6 +81,9 @@ extern int arc_debug;
struct gdbarch_tdep
{
+ /* Offset to PC value in jump buffer. If this is negative, longjmp
+ support will be disabled. */
+ int jb_pc;
};
/* Utility functions used by other ARC-specific modules. */