Re: [PATCH v2 4/7] gdbarch: add addressable_memory_unit_size method

Simon Marchi
2015-06-12T20:54:11Z

> This is the central place everyone should look at first to understand
> non 8-bit bytes targets. For extra clarity, could you please
> add "8-bit"s in there, say:
>
> "the size in 8-bit bytes" (...) to the number of 8-bit bytes associated to
> each address in memory."
>
> Looks good to me with that change.
>
> Thanks,
> Pedro Alves

Thanks, pushed with the change:

From 3374165f51fa3cc3ce1b1bf8c72293464da9d511 Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@ericsson.com>
Date: Fri, 12 Jun 2015 16:51:51 -0400
Subject: [PATCH] gdbarch: add addressable_memory_unit_size method

Add a new gdbarch method to get the length of an addressable memory unit
for a given architecture. The default implementation returns 1.

gdb/ChangeLog:

* arch-utils.h (default_addressable_memory_unit_size): New.
* arch-utils.c (default_addressable_memory_unit_size): New.
* gdbarch.sh (addressable_memory_unit_size): New.
* gdbarch.h: Re-generate.
* gdbarch.c: Re-generate.
---
gdb/ChangeLog | 8 ++++++++
gdb/arch-utils.c | 9 +++++++++
gdb/arch-utils.h | 1 +
gdb/gdbarch.c | 23 +++++++++++++++++++++++
gdb/gdbarch.h | 8 ++++++++
gdb/gdbarch.sh | 6 ++++++
6 files changed, 55 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index bde6f67..1b28992 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,13 @@
2015-06-12 Simon Marchi <simon.marchi@ericsson.com>

+ * arch-utils.h (default_addressable_memory_unit_size): New.
+ * arch-utils.c (default_addressable_memory_unit_size): New.
+ * gdbarch.sh (addressable_memory_unit_size): New.
+ * gdbarch.h: Re-generate.
+ * gdbarch.c: Re-generate.
+
+2015-06-12 Simon Marchi <simon.marchi@ericsson.com>
+
* target.c (target_read): Rename variables and use
TARGET_XFER_E_IO.
(target_read_with_progress): Same.
diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index 7f07e21..e9c622d 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -888,6 +888,15 @@ default_gnu_triplet_regexp (struct gdbarch *gdbarch)
return gdbarch_bfd_arch_info (gdbarch)->arch_name;
}

+/* Default method for gdbarch_addressable_memory_unit_size. By default, a memory byte has
+ a size of 1 octet. */
+
+int
+default_addressable_memory_unit_size (struct gdbarch *gdbarch)
+{
+ return 1;
+}
+
/* -Wmissing-prototypes */
extern initialize_file_ftype _initialize_gdbarch_utils;

diff --git a/gdb/arch-utils.h b/gdb/arch-utils.h
index 9cb28e4..27f4787 100644
--- a/gdb/arch-utils.h
+++ b/gdb/arch-utils.h
@@ -203,5 +203,6 @@ extern CORE_ADDR default_infcall_mmap (CORE_ADDR size, unsigned prot);
extern void default_infcall_munmap (CORE_ADDR addr, CORE_ADDR size);
extern char *default_gcc_target_options (struct gdbarch *gdbarch);
extern const char *default_gnu_triplet_regexp (struct gdbarch *gdbarch);
+extern int default_addressable_memory_unit_size (struct gdbarch *gdbarch);

#endif
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index cd82487..c289334 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -329,6 +329,7 @@ struct gdbarch
gdbarch_infcall_munmap_ftype *infcall_munmap;
gdbarch_gcc_target_options_ftype *gcc_target_options;
gdbarch_gnu_triplet_regexp_ftype *gnu_triplet_regexp;
+ gdbarch_addressable_memory_unit_size_ftype *addressable_memory_unit_size;
};

/* Create a new ``struct gdbarch'' based on information provided by
@@ -430,6 +431,7 @@ gdbarch_alloc (const struct gdbarch_info *info,
gdbarch->infcall_munmap = default_infcall_munmap;
gdbarch->gcc_target_options = default_gcc_target_options;
gdbarch->gnu_triplet_regexp = default_gnu_triplet_regexp;
+ gdbarch->addressable_memory_unit_size = default_addressable_memory_unit_size;
/* gdbarch_alloc() */

return gdbarch;
@@ -663,6 +665,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of infcall_munmap, invalid_p == 0 */
/* Skip verify of gcc_target_options, invalid_p == 0 */
/* Skip verify of gnu_triplet_regexp, invalid_p == 0 */
+ /* Skip verify of addressable_memory_unit_size, invalid_p == 0 */
buf = ui_file_xstrdup (log, &length);
make_cleanup (xfree, buf);
if (length > 0)
@@ -714,6 +717,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
"gdbarch_dump: address_to_pointer = <%s>\n",
host_address_to_string (gdbarch->address_to_pointer));
fprintf_unfiltered (file,
+ "gdbarch_dump: addressable_memory_unit_size = <%s>\n",
+ host_address_to_string (gdbarch->addressable_memory_unit_size));
+ fprintf_unfiltered (file,
"gdbarch_dump: gdbarch_adjust_breakpoint_address_p() = %d\n",
gdbarch_adjust_breakpoint_address_p (gdbarch));
fprintf_unfiltered (file,
@@ -4730,6 +4736,23 @@ set_gdbarch_gnu_triplet_regexp (struct gdbarch *gdbarch,
gdbarch->gnu_triplet_regexp = gnu_triplet_regexp;
}

+int
+gdbarch_addressable_memory_unit_size (struct gdbarch *gdbarch)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->addressable_memory_unit_size != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_addressable_memory_unit_size called\n");
+ return gdbarch->addressable_memory_unit_size (gdbarch);
+}
+
+void
+set_gdbarch_addressable_memory_unit_size (struct gdbarch *gdbarch,
+ gdbarch_addressable_memory_unit_size_ftype addressable_memory_unit_size)
+{
+ gdbarch->addressable_memory_unit_size = addressable_memory_unit_size;
+}
+

/* Keep a registry of per-architecture data-pointers required by GDB
modules. */
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index d2ccd2a..7d6a0cf 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -1466,6 +1466,14 @@ typedef const char * (gdbarch_gnu_triplet_regexp_ftype) (struct gdbarch *gdbarch
extern const char * gdbarch_gnu_triplet_regexp (struct gdbarch *gdbarch);
extern void set_gdbarch_gnu_triplet_regexp (struct gdbarch *gdbarch, gdbarch_gnu_triplet_regexp_ftype *gnu_triplet_regexp);

+/* Return the size in 8-bit bytes of an addressable memory unit on this
+ architecture. This corresponds to the number of 8-bit bytes associated to
+ each address in memory. */
+
+typedef int (gdbarch_addressable_memory_unit_size_ftype) (struct gdbarch *gdbarch);
+extern int gdbarch_addressable_memory_unit_size (struct gdbarch *gdbarch);
+extern void set_gdbarch_addressable_memory_unit_size (struct gdbarch *gdbarch, gdbarch_addressable_memory_unit_size_ftype *addressable_memory_unit_size);
+
/* Definition for an unknown syscall, used basically in error-cases. */
#define UNKNOWN_SYSCALL (-1)

diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index a3c903e..6c5d684 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -1113,6 +1113,12 @@ m:char *:gcc_target_options:void:::default_gcc_target_options::0
# returns the BFD architecture name, which is correct in nearly every
# case.
m:const char *:gnu_triplet_regexp:void:::default_gnu_triplet_regexp::0
+
+# Return the size in 8-bit bytes of an addressable memory unit on this
+# architecture. This corresponds to the number of 8-bit bytes associated to
+# each address in memory.
+m:int:addressable_memory_unit_size:void:::default_addressable_memory_unit_size::0
+
EOF
}

--
2.1.4