Re: [RFC, gdbserver] Avoid defining linux_read_offsets when the target does not need it

Luis Machado
2013-05-16T10:34:08Z

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On 05/15/2013 04:14 PM, Pedro Alves wrote:
> On 05/15/2013 12:25 PM, Luis Machado wrote:
>
>> * linux-low.c: Move definition checks upwards for PT_TEXT_ADDR,
>> PT_DATA_ADDR and PT_TEXT_END_ADDR. Update comments.
>> (linux_read_offsets): Remove PT_TEXT_ADDR, PT_DATA_ADDR and
>> PT_TEXT_END_ADDR guards. Update comments.
>> (linux_target_op) <read_offsets): Conditionally define to
>> linux_read_offsets if the target is UCLIBC and if it defines
>> PT_TEXT_ADDR, PT_DATA_ADDR and PT_TEXT_END_ADDR.
>
> This is OK.
>
>> +#if defined(__mcoldfire__)
>> +/* These are still undefined in recent (3.10) kernels. */
>> +#define PT_TEXT_ADDR 49*4
>> +#define PT_DATA_ADDR 50*4
>> +#define PT_TEXT_END_ADDR 51*4
>> +/* BFIN already defines these constants in recent (3.10) kernels. */
>> +#elif defined(BFIN)
>> +#define PT_TEXT_ADDR 220
>> +#define PT_TEXT_END_ADDR 224
>> +#define PT_DATA_ADDR 228
>> +/* These are still undefined in recent (3.10) kernels. */
>
> But please avoid "recent" "new", etc. in code. Those get old fast.
>
> Thanks,
>

Thanks. Here is what i checked in.

Luis

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2013-05-16 Luis Machado <lgustavo@codesourcery.com>

* linux-low.c: Move definition checks upwards for PT_TEXT_ADDR,
PT_DATA_ADDR and PT_TEXT_END_ADDR. Update comments.
(linux_read_offsets): Remove PT_TEXT_ADDR, PT_DATA_ADDR and
PT_TEXT_END_ADDR guards. Update comments.
(linux_target_op) <read_offsets>: Conditionally define to
linux_read_offsets if the target is UCLIBC and if it defines
PT_TEXT_ADDR, PT_DATA_ADDR and PT_TEXT_END_ADDR.

Index: gdb-head/gdb/gdbserver/linux-low.c
===================================================================
--- gdb-head.orig/gdb/gdbserver/linux-low.c 2013-04-17 10:24:52.859499119 +0200
+++ gdb-head/gdb/gdbserver/linux-low.c 2013-05-16 12:29:32.822525610 +0200
@@ -84,6 +84,30 @@
#endif
#endif

+/* Some targets did not define these ptrace constants from the start,
+ so gdbserver defines them locally here. In the future, these may
+ be removed after they are added to asm/ptrace.h. */
+#if !(defined(PT_TEXT_ADDR) \
+ || defined(PT_DATA_ADDR) \
+ || defined(PT_TEXT_END_ADDR))
+#if defined(__mcoldfire__)
+/* These are still undefined in 3.10 kernels. */
+#define PT_TEXT_ADDR 49*4
+#define PT_DATA_ADDR 50*4
+#define PT_TEXT_END_ADDR 51*4
+/* BFIN already defines these since at least 2.6.32 kernels. */
+#elif defined(BFIN)
+#define PT_TEXT_ADDR 220
+#define PT_TEXT_END_ADDR 224
+#define PT_DATA_ADDR 228
+/* These are still undefined in 3.10 kernels. */
+#elif defined(__TMS320C6X__)
+#define PT_TEXT_ADDR (0x10000*4)
+#define PT_DATA_ADDR (0x10004*4)
+#define PT_TEXT_END_ADDR (0x10008*4)
+#endif
+#endif
+
#ifdef HAVE_LINUX_BTRACE
# include "linux-btrace.h"
#endif
@@ -4833,25 +4857,14 @@ linux_stopped_data_address (void)
return lwp->stopped_data_address;
}

-#if defined(__UCLIBC__) && defined(HAS_NOMMU)
-#if ! (defined(PT_TEXT_ADDR) \
- || defined(PT_DATA_ADDR) \
- || defined(PT_TEXT_END_ADDR))
-#if defined(__mcoldfire__)
-/* These should really be defined in the kernel's ptrace.h header. */
-#define PT_TEXT_ADDR 49*4
-#define PT_DATA_ADDR 50*4
-#define PT_TEXT_END_ADDR 51*4
-#elif defined(BFIN)
-#define PT_TEXT_ADDR 220
-#define PT_TEXT_END_ADDR 224
-#define PT_DATA_ADDR 228
-#elif defined(__TMS320C6X__)
-#define PT_TEXT_ADDR (0x10000*4)
-#define PT_DATA_ADDR (0x10004*4)
-#define PT_TEXT_END_ADDR (0x10008*4)
-#endif
-#endif
+#if defined(__UCLIBC__) && defined(HAS_NOMMU) \
+ && defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) \
+ && defined(PT_TEXT_END_ADDR)
+
+/* This is only used for targets that define PT_TEXT_ADDR,
+ PT_DATA_ADDR and PT_TEXT_END_ADDR. If those are not defined, supposedly
+ the target has different ways of acquiring this information, like
+ loadmaps. */

/* Under uClinux, programs are loaded at non-zero offsets, which we need
to tell gdb about. */
@@ -4859,7 +4872,6 @@ linux_stopped_data_address (void)
static int
linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p)
{
-#if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR)
unsigned long text, text_end, data;
int pid = lwpid_of (get_thread_lwp (current_inferior));

@@ -4888,7 +4900,6 @@ linux_read_offsets (CORE_ADDR *text_p, C

return 1;
}
-#endif
return 0;
}
#endif
@@ -5887,7 +5898,9 @@ static struct target_ops linux_target_op
linux_remove_point,
linux_stopped_by_watchpoint,
linux_stopped_data_address,
-#if defined(__UCLIBC__) && defined(HAS_NOMMU)
+#if defined(__UCLIBC__) && defined(HAS_NOMMU) \
+ && defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) \
+ && defined(PT_TEXT_END_ADDR)
linux_read_offsets,
#else
NULL,