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

@@ -1,3 +1,11 @@
+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

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;
 

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

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)
@@ -713,6 +716,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
   fprintf_unfiltered (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));
@@ -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.  */

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)
 

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
 }