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Re: [patch/rfa] fix call-dummies for hppa
- From: Randolph Chung <randolph at tausq dot org>
- To: Andrew Cagney <cagney at gnu dot org>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Wed, 28 Apr 2004 10:18:20 -0700
- Subject: Re: [patch/rfa] fix call-dummies for hppa
- References: <20040424190231.GC2923@tausq.org> <408FD0E7.3000300@gnu.org>
- Reply-to: Randolph Chung <randolph at tausq dot org>
In reference to a message from Andrew Cagney, dated Apr 28:
> >This fixes a few bugs in the 32-bit version of the hppa push_dummy_call
> >method.
Updated version, passes all of structs.exp and call-sc.exp on hppa-linux
2004-04-28 Randolph Chung <tausq@debian.org>
* hppa-tdep.c (hppa32_return_value): Handle both 4- and 8-byte fp
return values.
(hppa32_push_dummy_call): Fix small struct and floating point argument
passing, and make sure the stack frame is properly aligned.
Index: hppa-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.c,v
retrieving revision 1.151
diff -u -p -r1.151 hppa-tdep.c
--- hppa-tdep.c 24 Apr 2004 06:13:32 -0000 1.151
+++ hppa-tdep.c 28 Apr 2004 17:14:54 -0000
@@ -121,22 +121,12 @@ hppa32_return_value (struct gdbarch *gdb
struct type *type, struct regcache *regcache,
void *readbuf, const void *writebuf)
{
- if (TYPE_CODE (type) == TYPE_CODE_FLT)
- {
- if (readbuf != NULL)
- regcache_cooked_read_part (regcache, FP4_REGNUM, 0,
- TYPE_LENGTH (type), readbuf);
- if (writebuf != NULL)
- regcache_cooked_write_part (regcache, FP4_REGNUM, 0,
- TYPE_LENGTH (type), writebuf);
- return RETURN_VALUE_REGISTER_CONVENTION;
- }
if (TYPE_LENGTH (type) <= 2 * 4)
{
/* The value always lives in the right hand end of the register
(or register pair)? */
int b;
- int reg = 28;
+ int reg = TYPE_CODE (type) == TYPE_CODE_FLT ? FP4_REGNUM : 28;
int part = TYPE_LENGTH (type) % 4;
/* The left hand register contains only part of the value,
transfer that first so that the rest can be xfered as entire
@@ -765,9 +755,6 @@ hppa32_push_dummy_call (struct gdbarch *
int nargs, struct value **args, CORE_ADDR sp,
int struct_return, CORE_ADDR struct_addr)
{
- /* NOTE: cagney/2004-02-27: This is a guess - its implemented by
- reverse engineering testsuite failures. */
-
/* Stack base address at which any pass-by-reference parameters are
stored. */
CORE_ADDR struct_end = 0;
@@ -784,9 +771,11 @@ hppa32_push_dummy_call (struct gdbarch *
for (write_pass = 0; write_pass < 2; write_pass++)
{
CORE_ADDR struct_ptr = 0;
- CORE_ADDR param_ptr = 0;
- int reg = 27; /* NOTE: Registers go down. */
+ /* The first parameter goes into sp-36, each stack slot is 4-bytes. */
+ CORE_ADDR param_ptr = 32;
int i;
+ int small_struct = 0;
+
for (i = 0; i < nargs; i++)
{
struct value *arg = args[i];
@@ -817,23 +806,64 @@ hppa32_push_dummy_call (struct gdbarch *
unpack_long (type,
VALUE_CONTENTS (arg)));
}
+ else if (TYPE_CODE (type) == TYPE_CODE_FLT)
+ {
+ /* Floating point value store, right aligned. */
+ param_len = align_up (TYPE_LENGTH (type), 4);
+ memcpy (param_val, VALUE_CONTENTS (arg), param_len);
+ }
else
{
- /* Small struct value, store right aligned? */
param_len = align_up (TYPE_LENGTH (type), 4);
+
+ /* Small struct value are stored right-aligned. */
memcpy (param_val + param_len - TYPE_LENGTH (type),
VALUE_CONTENTS (arg), TYPE_LENGTH (type));
+
+ /* Structures of size 5, 6 and 7 bytes are special in that
+ the higher-ordered word is stored in the lower-ordered
+ argument, and even though it is a 8-byte quantity the
+ registers need not be 8-byte aligned. */
+ if (param_len > 4)
+ small_struct = 1;
}
+
param_ptr += param_len;
- reg -= param_len / 4;
+ if (param_len == 8 && !small_struct)
+ param_ptr = align_up (param_ptr, 8);
+
+ /* First 4 non-FP arguments are passed in gr26-gr23.
+ First 4 32-bit FP arguments are passed in fr4L-fr7L.
+ First 2 64-bit FP arguments are passed in fr5 and fr7.
+
+ The rest go on the stack, starting at sp-36, towards lower
+ addresses. 8-byte arguments must be aligned to a 8-byte
+ stack boundary. */
if (write_pass)
{
write_memory (param_end - param_ptr, param_val, param_len);
- if (reg >= 23)
+
+ /* There are some cases when we don't know the type
+ expected by the callee (e.g. for variadic functions), so
+ pass the parameters in both general and fp regs. */
+ if (param_ptr <= 48)
{
- regcache_cooked_write (regcache, reg, param_val);
+ int grreg = 26 - (param_ptr - 36) / 4;
+ int fpLreg = 72 + (param_ptr - 36) / 4 * 2;
+ int fpreg = 74 + (param_ptr - 32) / 8 * 4;
+
+ regcache_cooked_write (regcache, grreg, param_val);
+ regcache_cooked_write (regcache, fpLreg, param_val);
+
if (param_len > 4)
- regcache_cooked_write (regcache, reg + 1, param_val + 4);
+ {
+ regcache_cooked_write (regcache, grreg + 1,
+ param_val + 4);
+
+ regcache_cooked_write (regcache, fpreg, param_val);
+ regcache_cooked_write (regcache, fpreg + 1,
+ param_val + 4);
+ }
}
}
}
@@ -841,13 +871,13 @@ hppa32_push_dummy_call (struct gdbarch *
/* Update the various stack pointers. */
if (!write_pass)
{
- struct_end = sp + struct_ptr;
+ struct_end = sp + align_up (struct_ptr, 64);
/* PARAM_PTR already accounts for all the arguments passed
by the user. However, the ABI mandates minimum stack
space allocations for outgoing arguments. The ABI also
mandates minimum stack alignments which we must
preserve. */
- param_end = struct_end + max (align_up (param_ptr, 8), 16);
+ param_end = struct_end + align_up (param_ptr, 64);
}
}
@@ -860,10 +890,9 @@ hppa32_push_dummy_call (struct gdbarch *
regcache_cooked_write_unsigned (regcache, RP_REGNUM, bp_addr);
/* Update the Stack Pointer. */
- regcache_cooked_write_unsigned (regcache, SP_REGNUM, param_end + 32);
+ regcache_cooked_write_unsigned (regcache, SP_REGNUM, param_end);
- /* The stack will have 32 bytes of additional space for a frame marker. */
- return param_end + 32;
+ return param_end;
}
/* This function pushes a stack frame with arguments as part of the