[commit 3/4] Revert use of memory_args_by_pointer in i386 gdbarch_tdep.

Joel Brobecker
2013-09-24T16:33:48Z

This is no longer useful, as it was introduced to reuse the funcall
handling code in amd64-tdep.c in the context of x64-windows. But
we have since then changed the implementations to be completely
independent of each other.

This reverts the non-windows-specific part of the change called:
amd64-windows: memory args passed by pointer during function calls.
(the x64-windows portion has already been reverted)

gdb/ChangeLog:

Revert:
* i386-tdep.h (gdbarch_tdep): Add field memory_args_by_pointer.
* amd64-tdep.c (amd64_push_arguments): Add handling of architectures
where tdep->memory_args_by_pointer is non-zero.

Tested on x86_64-linux, checked in.

---
gdb/ChangeLog | 7 +++++++
gdb/amd64-tdep.c | 40 ++++++----------------------------------
gdb/i386-tdep.h | 9 ---------
3 files changed, 13 insertions(+), 43 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 1977ff0..cd03e31 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,6 +1,13 @@
2013-09-24 Joel Brobecker <brobecker@adacore.com>

Revert:
+ * i386-tdep.h (gdbarch_tdep): Add field memory_args_by_pointer.
+ * amd64-tdep.c (amd64_push_arguments): Add handling of architectures
+ where tdep->memory_args_by_pointer is non-zero.
+
+2013-09-24 Joel Brobecker <brobecker@adacore.com>
+
+ Revert:
* i386-tdep.h (struct gdbarch_tdep): Add new field
integer_param_regs_saved_in_caller_frame.
* amd64-tdep.c (amd64_push_dummy_call): Allocate some memory on
diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index ec6bfc6..35526cf 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -749,8 +749,7 @@ static CORE_ADDR
amd64_push_arguments (struct regcache *regcache, int nargs,
struct value **args, CORE_ADDR sp, int struct_return)
{
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
- struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+ struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
int *integer_regs = tdep->call_dummy_integer_regs;
int num_integer_regs = tdep->call_dummy_num_integer_regs;

@@ -763,11 +762,6 @@ amd64_push_arguments (struct regcache *regcache, int nargs,
AMD64_XMM0_REGNUM + 6, AMD64_XMM0_REGNUM + 7,
};
struct value **stack_args = alloca (nargs * sizeof (struct value *));
- /* An array that mirrors the stack_args array. For all arguments
- that are passed by MEMORY, if that argument's address also needs
- to be stored in a register, the ARG_ADDR_REGNO array will contain
- that register number (or a negative value otherwise). */
- int *arg_addr_regno = alloca (nargs * sizeof (int));
int num_stack_args = 0;
int num_elements = 0;
int element = 0;
@@ -811,19 +805,7 @@ amd64_push_arguments (struct regcache *regcache, int nargs,
{
/* The argument will be passed on the stack. */
num_elements += ((len + 7) / 8);
- stack_args[num_stack_args] = args[i];
- /* If this is an AMD64_MEMORY argument whose address must also
- be passed in one of the integer registers, reserve that
- register and associate this value to that register so that
- we can store the argument address as soon as we know it. */
- if (class[0] == AMD64_MEMORY
- && tdep->memory_args_by_pointer
- && integer_reg < tdep->call_dummy_num_integer_regs)
- arg_addr_regno[num_stack_args] =
- tdep->call_dummy_integer_regs[integer_reg++];
- else
- arg_addr_regno[num_stack_args] = -1;
- num_stack_args++;
+ stack_args[num_stack_args++] = args[i];
}
else
{
@@ -878,20 +860,10 @@ amd64_push_arguments (struct regcache *regcache, int nargs,
{
struct type *type = value_type (stack_args[i]);
const gdb_byte *valbuf = value_contents (stack_args[i]);
- CORE_ADDR arg_addr = sp + element * 8;
-
- write_memory (arg_addr, valbuf, TYPE_LENGTH (type));
- if (arg_addr_regno[i] >= 0)
- {
- /* We also need to store the address of that argument in
- the given register. */
- gdb_byte buf[8];
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-
- store_unsigned_integer (buf, 8, byte_order, arg_addr);
- regcache_cooked_write (regcache, arg_addr_regno[i], buf);
- }
- element += ((TYPE_LENGTH (type) + 7) / 8);
+ int len = TYPE_LENGTH (type);
+
+ write_memory (sp + element * 8, valbuf, len);
+ element += ((len + 7) / 8);
}

/* The psABI says that "For calls that may call functions that use
diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
index 8113dcc..0c408fa 100644
--- a/gdb/i386-tdep.h
+++ b/gdb/i386-tdep.h
@@ -85,15 +85,6 @@ struct gdbarch_tdep
the result in CLASS. Used on amd64 only. */
void (*classify) (struct type *type, enum amd64_reg_class class[2]);

- /* Non-zero if the first few MEMORY arguments should be passed by
- pointer.
-
- More precisely, MEMORY arguments are passed through the stack.
- But certain architectures require that their address be passed
- by register as well, if there are still some integer registers
- available for argument passing. */
- int memory_args_by_pointer;
-
/* Floating-point registers. */
struct regset *fpregset;
size_t sizeof_fpregset;
--
1.8.1.2