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[commit] Float parameter passing in funcall on ppc-aix & ppc-lynx178.
- From: Joel Brobecker <brobecker at adacore dot com>
- To: gdb-patches at sourceware dot org
- Date: Mon, 13 May 2013 14:31:12 +0400
- Subject: [commit] Float parameter passing in funcall on ppc-aix & ppc-lynx178.
Hello,
Given the following code:
float global_float = 0.0;
void
set_float (float f)
{
global_float = f;
}
GDB incorrectly calls set_float if the set_float function is marked
as prototyped:
(gdb) call set_float (5.0)
(gdb) print global_float
$1 = 2048
What happens, when the function is marked as prototyped, is that
GDB finds that the argument is a float, casts the value given in
the expression to a float, and then gives that float to ppc-aix/
ppc-lynx178's push_dummy_call gdbarch routine. The latter then blindly
copies it as is in the first floating-point register, instead of
making sure that it has the proper format first.
This patch fixes the problem by following the same approach as
the one used in ppc_sysv_abi_push_dummy_call, converting the FP
value to the register type before copying its contents.
This requires, but is otherwise indenpendent of:
http://www.sourceware.org/ml/gdb-patches/2013-05/msg00427.html
gdb/ChangeLog:
* rs6000-aix-tdep.c (rs6000_push_dummy_call): Convert
floating point registers to register type before storing
value.
* rs6000-lynx178-tdep.c (rs6000_lynx178_push_dummy_call):
Likewise.
Tested on ppc-aix and ppc-lynx178. Checked in.
---
gdb/ChangeLog | 8 ++++++++
gdb/rs6000-aix-tdep.c | 15 ++++++++++-----
gdb/rs6000-lynx178-tdep.c | 14 ++++++++++----
3 files changed, 28 insertions(+), 9 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 84159e1..e3c2c4b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2013-05-13 Joel Brobecker <brobecker@adacore.com>
+
+ * rs6000-aix-tdep.c (rs6000_push_dummy_call): Convert
+ floating point registers to register type before storing
+ value.
+ * rs6000-lynx178-tdep.c (rs6000_lynx178_push_dummy_call):
+ Likewise.
+
2013-05-10 Joel Brobecker <brobecker@adacore.com>
Tom Tromey <tromey@redhat.com>
diff --git a/gdb/rs6000-aix-tdep.c b/gdb/rs6000-aix-tdep.c
index 0992213..0d4fec5 100644
--- a/gdb/rs6000-aix-tdep.c
+++ b/gdb/rs6000-aix-tdep.c
@@ -254,16 +254,21 @@ rs6000_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
if (TYPE_CODE (type) == TYPE_CODE_FLT)
{
-
/* Floating point arguments are passed in fpr's, as well as gpr's.
There are 13 fpr's reserved for passing parameters. At this point
- there is no way we would run out of them. */
+ there is no way we would run out of them.
+
+ Always store the floating point value using the register's
+ floating-point format. */
+ const int fp_regnum = tdep->ppc_fp0_regnum + 1 + f_argno;
+ gdb_byte reg_val[MAX_REGISTER_SIZE];
+ struct type *reg_type = register_type (gdbarch, fp_regnum);
gdb_assert (len <= 8);
- regcache_cooked_write (regcache,
- tdep->ppc_fp0_regnum + 1 + f_argno,
- value_contents (arg));
+ convert_typed_floating (value_contents (arg), type,
+ reg_val, reg_type);
+ regcache_cooked_write (regcache, fp_regnum, reg_val);
++f_argno;
}
diff --git a/gdb/rs6000-lynx178-tdep.c b/gdb/rs6000-lynx178-tdep.c
index 90730ab..47fcc62 100644
--- a/gdb/rs6000-lynx178-tdep.c
+++ b/gdb/rs6000-lynx178-tdep.c
@@ -100,13 +100,19 @@ rs6000_lynx178_push_dummy_call (struct gdbarch *gdbarch,
/* Floating point arguments are passed in fpr's, as well as gpr's.
There are 13 fpr's reserved for passing parameters. At this point
- there is no way we would run out of them. */
+ there is no way we would run out of them.
+
+ Always store the floating point value using the register's
+ floating-point format. */
+ const int fp_regnum = tdep->ppc_fp0_regnum + 1 + f_argno;
+ gdb_byte reg_val[MAX_REGISTER_SIZE];
+ struct type *reg_type = register_type (gdbarch, fp_regnum);
gdb_assert (len <= 8);
- regcache_cooked_write (regcache,
- tdep->ppc_fp0_regnum + 1 + f_argno,
- value_contents (arg));
+ convert_typed_floating (value_contents (arg), type,
+ reg_val, reg_type);
+ regcache_cooked_write (regcache, fp_regnum, reg_val);
++f_argno;
}
--
1.7.10.4