Split size in regset section iterators

In the existing code, when using the regset section iteration functions, the
size parameter is used in different ways.

With collect, size is used to create the buffer in which to write the regset.
(see linux-tdep.c::linux_collect_regset_section_cb).

With supply, size is used to confirm the existing regset is the correct size.
If REGSET_VARIABLE_SIZE is set then the regset can be bigger than size.
Effectively, size is the minimum possible size of the regset.
(see corelow.c::get_core_register_section).

There are currently no targets with both REGSET_VARIABLE_SIZE and a collect
function.
In SVE, a corefile can contain one of two formats after the header, both of
which are different sizes. However, when writing a core file, we always want
to write out the full bigger size.

To allow support of collects for REGSET_VARIABLE_SIZE we need two sizes.
This is done by adding supply_size and collect_size.

gdb/

	* aarch64-fbsd-tdep.c
	(aarch64_fbsd_iterate_over_regset_sections): Add supply_size and
	collect_size.
	* aarch64-linux-tdep.c
	(aarch64_linux_iterate_over_regset_sections): Likewise.
	* alpha-linux-tdep.c
	(alpha_linux_iterate_over_regset_sections):
	* alpha-nbsd-tdep.c
	(alphanbsd_iterate_over_regset_sections): Likewise.
	* amd64-fbsd-tdep.c
	(amd64fbsd_iterate_over_regset_sections): Likewise.
	* amd64-linux-tdep.c
	(amd64_linux_iterate_over_regset_sections): Likewise.
	* arm-bsd-tdep.c
	(armbsd_iterate_over_regset_sections): Likewise.
	* arm-fbsd-tdep.c
	(arm_fbsd_iterate_over_regset_sections): Likewise.
	* arm-linux-tdep.c
	(arm_linux_iterate_over_regset_sections): Likewise.
	* corelow.c (get_core_registers_cb): Likewise.
	(core_target::fetch_registers): Likewise.
	* fbsd-tdep.c (fbsd_collect_regset_section_cb): Likewise.
	* frv-linux-tdep.c (frv_linux_iterate_over_regset_sections): Likewise.
	* gdbarch.h (void): Regenerate.
	* gdbarch.sh: Add supply_size and collect_size.
	* hppa-linux-tdep.c (hppa_linux_iterate_over_regset_sections): Likewise.
	* hppa-nbsd-tdep.c (hppanbsd_iterate_over_regset_sections): Likewise.
	* hppa-obsd-tdep.c (hppaobsd_iterate_over_regset_sections): Likewise.
	* i386-fbsd-tdep.c (i386fbsd_iterate_over_regset_sections): Likewise.
	* i386-linux-tdep.c (i386_linux_iterate_over_regset_sections): Likewise.
	* i386-tdep.c (i386_iterate_over_regset_sections): Likewise.
	* ia64-linux-tdep.c (ia64_linux_iterate_over_regset_sections): Likewise.
	* linux-tdep.c (linux_collect_regset_section_cb): Likewise.
	* m32r-linux-tdep.c (m32r_linux_iterate_over_regset_sections): Likewise.
	* m68k-bsd-tdep.c (m68kbsd_iterate_over_regset_sections): Likewise.
	* m68k-linux-tdep.c (m68k_linux_iterate_over_regset_sections): Likewise.
	* mips-fbsd-tdep.c (mips_fbsd_iterate_over_regset_sections): Likewise.
	* mips-linux-tdep.c (mips_linux_iterate_over_regset_sections): Likewise.
	* mips-nbsd-tdep.c (mipsnbsd_iterate_over_regset_sections): Likewise.
	* mips64-obsd-tdep.c (mips64obsd_iterate_over_regset_sections): Likewise.
	* mn10300-linux-tdep.c (am33_iterate_over_regset_sections): Likewise.
	* nios2-linux-tdep.c (nios2_iterate_over_regset_sections): Likewise.
	* ppc-fbsd-tdep.c (ppcfbsd_iterate_over_regset_sections): Likewise.
	* ppc-linux-tdep.c (ppc_linux_iterate_over_regset_sections): Likewise.
	* ppc-nbsd-tdep.c (ppcnbsd_iterate_over_regset_sections): Likewise.
	* ppc-obsd-tdep.c (ppcobsd_iterate_over_regset_sections): Likewise.
	* riscv-linux-tdep.c (riscv_linux_iterate_over_regset_sections): Likewise.
	* rs6000-aix-tdep.c (rs6000_aix_iterate_over_regset_sections): Likewise.
	* s390-linux-tdep.c (s390_iterate_over_regset_sections): Likewise.
	* score-tdep.c (score7_linux_iterate_over_regset_sections): Likewise.
	* sh-tdep.c (sh_iterate_over_regset_sections): Likewise.
	* sparc-tdep.c (sparc_iterate_over_regset_sections): Likewise.
	* tilegx-linux-tdep.c (tilegx_iterate_over_regset_sections): Likewise.
	* vax-tdep.c (vax_iterate_over_regset_sections): Likewise.
	* xtensa-tdep.c (xtensa_iterate_over_regset_sections): Likewise.

1 files changed, 7 insertions, 5 deletions

diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 0df1fd16926..b563f8d165a 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -92,13 +92,15 @@ typedef int (iterate_over_objfiles_in_search_order_cb_ftype)
 
 /* Callback type for regset section iterators.  The callback usually
    invokes the REGSET's supply or collect method, to which it must
-   pass a buffer with at least the given SIZE.  SECT_NAME is a BFD
-   section name, and HUMAN_NAME is used for diagnostic messages.
-   CB_DATA should have been passed unchanged through the iterator.  */
+   pass a buffer - for collects this buffer will need to be created using
+   COLLECT_SIZE, for supply the existing buffer being read from should
+   be at least SUPPLY_SIZE.  SECT_NAME is a BFD section name, and HUMAN_NAME
+   is used for diagnostic messages.  CB_DATA should have been passed
+   unchanged through the iterator.  */
 
 typedef void (iterate_over_regset_sections_cb)
-  (const char *sect_name, int size, const struct regset *regset,
-   const char *human_name, void *cb_data);
+  (const char *sect_name, int supply_size, int collect_size,
+   const struct regset *regset, const char *human_name, void *cb_data);
 
 
 /* The following are pre-initialized by GDBARCH.  */