[RFC/TileGX 1/6] fix args alignment bug

Jiong Wang
2013-01-18T09:23:42Z

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for tilegx, args pushed on stack should be aligned to 64bit.

gdb/ChangeLog:

* tilegx-tdep.c (tilegx_push_dummy_call): args pushed on stack
should be aligned to 64bit.

please review.

---
Regards,
Jiong
Tilera Corporation.

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---
gdb/tilegx-tdep.c | 20 ++++----------------
1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/gdb/tilegx-tdep.c b/gdb/tilegx-tdep.c
index 0c560ba..2f1d824 100644
--- a/gdb/tilegx-tdep.c
+++ b/gdb/tilegx-tdep.c
@@ -292,7 +292,7 @@ tilegx_push_dummy_call (struct gdbarch *gdbarch,
int argreg = TILEGX_R0_REGNUM;
int i, j;
int typelen, slacklen, alignlen;
- static const gdb_byte two_zero_words[8] = { 0 };
+ static const gdb_byte four_zero_words[16] = { 0 };

/* If struct_return is 1, then the struct return address will
consume one argument-passing register. */
@@ -326,18 +326,6 @@ tilegx_push_dummy_call (struct gdbarch *gdbarch,
/* Align SP. */
stack_dest = tilegx_frame_align (gdbarch, stack_dest);

- /* Loop backwards through arguments to determine stack alignment. */
- alignlen = 0;
-
- for (j = nargs - 1; j >= i; j--)
- {
- typelen = TYPE_LENGTH (value_enclosing_type (args[j]));
- alignlen += (typelen + 3) & (~3);
- }
-
- if (alignlen & 0x4)
- stack_dest -= 4;
-
/* Loop backwards through remaining arguments and push them on
the stack, word aligned. */
for (j = nargs - 1; j >= i; j--)
@@ -347,7 +335,7 @@ tilegx_push_dummy_call (struct gdbarch *gdbarch,
const gdb_byte *contents = value_contents (args[j]);

typelen = TYPE_LENGTH (value_enclosing_type (args[j]));
- slacklen = ((typelen + 3) & (~3)) - typelen;
+ slacklen = ((typelen + 7) & (~7)) - typelen;
val = xmalloc (typelen + slacklen);
back_to = make_cleanup (xfree, val);
memcpy (val, contents, typelen);
@@ -360,8 +348,8 @@ tilegx_push_dummy_call (struct gdbarch *gdbarch,
}

/* Add 2 words for linkage space to the stack. */
- stack_dest = stack_dest - 8;
- write_memory (stack_dest, two_zero_words, 8);
+ stack_dest = stack_dest - 16;
+ write_memory (stack_dest, four_zero_words, 16);

/* Update stack pointer. */
regcache_cooked_write_unsigned (regcache, TILEGX_SP_REGNUM, stack_dest);
--
1.7.10.3