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Re: [RFA 1/2] mips: Switch inferior function calls to ON_STACK method.
> gdb/ChangeLog:
>
> * mips-tdep.c (mips_push_dummy_code): New function.
> (mips_gdbarch_init): Set the gdbarch call_dummy_location to
> ON_STACK and install mips_push_dummy_code as our gdbarch
> push_dummy_code routine.
Second version of this patch with Mark's style comments addressed.
--
Joel
commit d7f93872c27075342da02ab2ee57062d8b9511c9
Author: Joel Brobecker <brobecker@adacore.com>
Date: Wed May 2 20:39:57 2012 -0400
mips: Switch inferior function calls to ON_STACK method.
This patch switches the mips code to use the ON_STACK method
for function calls instead of AT_SYMBOL, which we want to remove.
gdb/ChangeLog:
* mips-tdep.c (mips_push_dummy_code): New function.
(mips_gdbarch_init): Set the gdbarch call_dummy_location to
ON_STACK and install mips_push_dummy_code as our gdbarch
push_dummy_code routine.
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 9a3c7fb..5faf114 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -3009,6 +3009,37 @@ mips_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr)
return align_down (addr, 16);
}
+/* Implement the push_dummy_code gdbarch method for mips targets. */
+
+static CORE_ADDR
+mips_push_dummy_code (struct gdbarch *gdbarch, CORE_ADDR sp,
+ CORE_ADDR funaddr, struct value **args,
+ int nargs, struct type *value_type,
+ CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
+ struct regcache *regcache)
+{
+ int bp_len;
+ gdb_byte null_insn[4] = { 0 };
+
+ *bp_addr = mips_frame_align (gdbarch, sp);
+ gdbarch_breakpoint_from_pc (gdbarch, bp_addr, &bp_len);
+
+ /* The breakpoint layer automatically adjusts the address of
+ breakpoints inserted in a branch delay slot. With enough
+ bad luck, the 4 bytes located just before our breakpoint
+ instruction could look like a branch instruction, and thus
+ trigger the adjustement, and break the function call entirely.
+ So, we reserve those 4 bytes and write a null instruction
+ to prevent that from happening. */
+ write_memory (*bp_addr - bp_len, null_insn, sizeof (null_insn));
+ sp = mips_frame_align (gdbarch, *bp_addr - 2 * bp_len);
+
+ /* Inferior resumes at the function entry point. */
+ *real_pc = funaddr;
+
+ return sp;
+}
+
static CORE_ADDR
mips_eabi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
struct regcache *regcache, CORE_ADDR bp_addr,
@@ -6906,10 +6937,8 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
/* MIPS version of CALL_DUMMY. */
- /* NOTE: cagney/2003-08-05: Eventually call dummy location will be
- replaced by a command, and all targets will default to on stack
- (regardless of the stack's execute status). */
- set_gdbarch_call_dummy_location (gdbarch, AT_SYMBOL);
+ set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
+ set_gdbarch_push_dummy_code (gdbarch, mips_push_dummy_code);
set_gdbarch_frame_align (gdbarch, mips_frame_align);
set_gdbarch_convert_register_p (gdbarch, mips_convert_register_p);