Re: [PATCH] Make host_address_to_string/gdb_print_host_address cast parameter to 'void *'

Simon Marchi
2015-10-27T16:55:52Z

On 27 October 2015 at 12:01, Pedro Alves <palves@redhat.com> wrote:
> Fixes a set of errors like:
>
> ../../src/gdb/symfile-debug.c: In function ‘int debug_qf_map_symtabs_matching_filename(objfile*, const char*, const char*, int (*)(symtab*, void*), void*)’:
> ../../src/gdb/symfile-debug.c:137:39: error: invalid conversion from ‘int (*)(symtab*, void*)’ to ‘const void*’ [-fpermissive]
> host_address_to_string (callback),
> ^
>
> Note this has to work with data and function pointers. In C++11 we
> may perhaps do something a bit safer, but we're not there yet, and I
> don't think it really matters. For now just always do a simple
> C-style cast in host_address_to_string itself. No point in adding a
> void * cast to each and every caller.
>
> gdb/ChangeLog:
> 2015-10-27 Pedro Alves <palves@redhat.com>
>
> * common/print-utils.c (host_address_to_string): Undef.
> * common/print-utils.h (host_address_to_string): Add a wrapper
> macro around the host_address_to_string function.
> * utils.c ():

You can drop this last line.

> * utils.c (gdb_print_host_address): Undef.
> * utils.h (gdb_print_host_address): Add a wrapper macro around the
> host_address_to_string function.
> ---
> gdb/common/print-utils.c | 2 ++
> gdb/common/print-utils.h | 4 ++++
> gdb/utils.c | 2 ++
> gdb/utils.h | 4 ++++
> 4 files changed, 12 insertions(+)
>
> diff --git a/gdb/common/print-utils.c b/gdb/common/print-utils.c
> index 1c1a5c1..bd62503 100644
> --- a/gdb/common/print-utils.c
> +++ b/gdb/common/print-utils.c
> @@ -315,6 +315,8 @@ core_addr_to_string_nz (const CORE_ADDR addr)
>
> /* See print-utils.h. */
>
> +#undef host_address_to_string
> +
> const char *
> host_address_to_string (const void *addr)
> {
> diff --git a/gdb/common/print-utils.h b/gdb/common/print-utils.h
> index 8d16966..abeb003 100644
> --- a/gdb/common/print-utils.h
> +++ b/gdb/common/print-utils.h
> @@ -67,4 +67,8 @@ extern const char *core_addr_to_string_nz (const CORE_ADDR addr);
>
> extern const char *host_address_to_string (const void *addr);
>
> +/* Wrapper that avoids adding a pointless cast to all callers. */
> +#define host_address_to_string(ADDR) \
> + host_address_to_string ((const void *) (ADDR))
> +
> #endif /* COMMON_CELLS_H */
> diff --git a/gdb/utils.c b/gdb/utils.c
> index afeff12..101e438 100644
> --- a/gdb/utils.c
> +++ b/gdb/utils.c
> @@ -1103,6 +1103,8 @@ print_spaces (int n, struct ui_file *file)
>
> /* Print a host address. */
>
> +#undef gdb_print_host_address
> +
> void
> gdb_print_host_address (const void *addr, struct ui_file *stream)
> {
> diff --git a/gdb/utils.h b/gdb/utils.h
> index 995a1cf..a226744 100644
> --- a/gdb/utils.h
> +++ b/gdb/utils.h
> @@ -248,6 +248,10 @@ extern int filtered_printing_initialized (void);
> /* Display the host ADDR on STREAM formatted as ``0x%x''. */
> extern void gdb_print_host_address (const void *addr, struct ui_file *stream);
>
> +/* Wrapper that avoids adding a pointless cast to all callers. */
> +#define gdb_print_host_address(ADDR, STREAM) \
> + gdb_print_host_address ((const void *) ADDR, STREAM)
> +
> /* Convert CORE_ADDR to string in platform-specific manner.
> This is usually formatted similar to 0x%lx. */
> extern const char *paddress (struct gdbarch *gdbarch, CORE_ADDR addr);
> --
> 1.9.3

I'm not a fan of the #undef, it makes it harder to follow what's
happening. Why not just rename the existing function to
host_address_to_string_1?

Same for gdb_print_host_address.