[RFA] Fix float argument passing in inferior function calls for ppc64

[RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

[-- Attachment #1: Type: text/plain, Size: 1416 bytes --]

Hi,

The 64-bit PowerPC ELF ABI version 1.9 says that "single precision
floating point values are mapped to the second word in a single
doubleword". The ppc64_sysv_abi_push_dummy_call function in
ppc-sysv-tdep.c, however, implements version 1.7 of the ABI which says
that they should go in the first doubleword.

Because of this, if you are calling a function with many arguments and
some need to be passed on the stack, GDB will get it wrong for 32-bit
floats. This is why in Linux/ppc64 GDB fails the "Call function with
many float arguments" test posted here:

http://sourceware.org/ml/gdb-patches/2008-01/msg00291.html

This patch fixes the test. It makes GDB pass 32-bit floats in the second
word when passing them in the stack as stated in the current ABI.

I didn't touch the code which writes the float to a general register in
the first word because I'm not sure how to test it. It is probably
related to soft-float, I guess.

Tested on Linux/ppc64 with no regressions. I believe this will also fix
other operating systems supported by GDB on ppc64 since they use the
same push_dummy_call implementation (assuming they also follow the
current SysV ABI), but I don't have the means to test them either.

Maybe someone could test the patch and the testcase in *BSD? Luis' patch
which has the testcases would also need this testing.
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

[-- Attachment #2: ppc64-abi-float-fix.diff --]
[-- Type: text/x-patch, Size: 8324 bytes --]

2008-01-14  Thiago Jung Bauermann  <bauerman@br.ibm.com>

	* ppc-sysv-tdep.c (ppc64_sysv_abi_push_dummy_call): Use 64-bit slot
	to pass 32-bit float argument when writing it on the stack. Map it
	to second word in the doubleword.

diff --git a/gdb/ppc-sysv-tdep.c b/gdb/ppc-sysv-tdep.c
index 9238f26..e993d1b 100644
--- a/gdb/ppc-sysv-tdep.c
+++ b/gdb/ppc-sysv-tdep.c
@@ -829,6 +829,7 @@ ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	  struct value *arg = args[argno];
 	  struct type *type = check_typedef (value_type (arg));
 	  const bfd_byte *val = value_contents (arg);
+
 	  if (TYPE_CODE (type) == TYPE_CODE_FLT && TYPE_LENGTH (type) <= 8)
 	    {
 	      /* Floats and Doubles go in f1 .. f13.  They also
@@ -836,11 +837,14 @@ ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	         memory.  */
 	      if (write_pass)
 		{
+		  gdb_byte regval[MAX_REGISTER_SIZE];
+		  const gdb_byte *p;
+
 		  if (freg <= 13)
 		    {
-		      gdb_byte regval[MAX_REGISTER_SIZE];
 		      struct type *regtype
                         = register_type (gdbarch, tdep->ppc_fp0_regnum);
+
 		      convert_typed_floating (val, type, regval, regtype);
 		      regcache_cooked_write (regcache,
                                              tdep->ppc_fp0_regnum + freg,
@@ -856,20 +860,35 @@ ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		         general registers").
 
 		         This code interprets that to mean: store it,
-		         left aligned, in the general register.  */
-		      gdb_byte regval[MAX_REGISTER_SIZE];
+		         left aligned, in the general register.
+
+		         NOTE: This was true in version 1.7 of the ABI,
+		         but it is not in version 1.9.  */
 		      memset (regval, 0, sizeof regval);
 		      memcpy (regval, val, TYPE_LENGTH (type));
 		      regcache_cooked_write (regcache,
 					     tdep->ppc_gp0_regnum + greg,
 					     regval);
 		    }
-		  write_memory (gparam, val, TYPE_LENGTH (type));
+
+		  /* "Single precision floating point values are mapped to
+		     the second word in a single doubleword."
+		     - 64-bit PowerPC ELF ABI version 1.9, page 16.  */
+		  if (TYPE_LENGTH (type) == 4)
+		    {
+		      memcpy (regval + 4, val, 4);
+		      p = regval;
+		    }
+		  else
+		    p = val;
+
+		  write_memory (gparam, p, 8);
 		}
-	      /* Always consume parameter stack space.  */
+
 	      freg++;
 	      greg++;
-	      gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
+	      /* Always consume parameter stack space.  */
+	      gparam = align_up (gparam + 8, tdep->wordsize);
 	    }
 	  else if (TYPE_CODE (type) == TYPE_CODE_FLT
 		   && TYPE_LENGTH (type) == 16
diff --git a/gdb/testsuite/gdb.base/callfuncs.c b/gdb/testsuite/gdb.base/callfuncs.c
index 4903868..d546051 100644
--- a/gdb/testsuite/gdb.base/callfuncs.c
+++ b/gdb/testsuite/gdb.base/callfuncs.c
@@ -46,9 +46,35 @@ long long_val2 = -321;
 
 float float_val1 = 3.14159;
 float float_val2 = -2.3765;
+float float_val3 = 0.25;
+float float_val4 = 1.25;
+float float_val5 = 2.25;
+float float_val6 = 3.25;
+float float_val7 = 4.25;
+float float_val8 = 5.25;
+float float_val9 = 6.25;
+float float_val10 = 7.25;
+float float_val11 = 8.25;
+float float_val12 = 9.25;
+float float_val13 = 10.25;
+float float_val14 = 11.25;
+float float_val15 = 12.25;
 
 double double_val1 = 45.654;
 double double_val2 = -67.66;
+double double_val3 = 0.25;
+double double_val4 = 1.25;
+double double_val5 = 2.25;
+double double_val6 = 3.25;
+double double_val7 = 4.25;
+double double_val8 = 5.25;
+double double_val9 = 6.25;
+double double_val10 = 7.25;
+double double_val11 = 8.25;
+double double_val12 = 9.25;
+double double_val13 = 10.25;
+double double_val14 = 11.25;
+double double_val15 = 12.25;
 
 #define DELTA (0.001)
 
@@ -298,6 +324,39 @@ t_float_values2 (float float_arg1, float float_arg2)
 	  && (float_arg2 - float_val2) > -DELTA);
 }
 
+/* This function has many arguments to force some of them to be passed via
+   the stack instead of registers, to test that GDB can construct correctly
+   the parameter save area. Note that Linux/ppc32 has 8 float registers to use
+   for float parameter passing and Linux/ppc64 has 13, so the number of
+   arguments has to be at least 14 to contemplate these platforms.  */
+
+float
+#ifdef NO_PROTOTYPES
+t_float_many_args (f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13,
+		   f14, f15)
+     float f1, float f2, float f3, float f4, float f5, float f6, float f7,
+     float f8, float f9, float f10, float f11, float f12, float f13, float f14,
+     float f15;
+#else
+t_float_many_args (float f1, float f2, float f3, float f4, float f5, float f6,
+		   float f7, float f8, float f9, float f10, float f11,
+		   float f12, float f13, float f14, float f15)
+#endif
+{
+  float sum_args;
+  float sum_values;
+
+  sum_args = f1 + f2 + f3 + f4 + f5 + f6 + f7 + f8 + f9 + f10 + f11 + f12
+	     + f13 + f14 + f15;
+  sum_values = float_val1 + float_val2 + float_val3 + float_val4 + float_val5
+	       + float_val6 + float_val7 + float_val8 + float_val9
+	       + float_val10 + float_val11 + float_val12 + float_val13
+	       + float_val14 + float_val15;
+
+  return ((sum_args - sum_values) < DELTA
+	  && (sum_args - sum_values) > -DELTA);
+}
+
 #ifdef PROTOTYPES
 int t_double_values (double double_arg1, double double_arg2)
 #else
@@ -311,6 +370,39 @@ double double_arg1, double_arg2;
 	  && (double_arg2 - double_val2) > -DELTA);
 }
 
+/* This function has many arguments to force some of them to be passed via
+   the stack instead of registers, to test that GDB can construct correctly
+   the parameter save area. Note that Linux/ppc32 has 8 float registers to use
+   for float parameter passing and Linux/ppc64 has 13, so the number of
+   arguments has to be at least 14 to contemplate these platforms.  */
+
+double
+#ifdef NO_PROTOTYPES
+t_double_many_args (f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13,
+		   f14, f15)
+     double f1, double f2, double f3, double f4, double f5, double f6,
+     double f7, double f8, double f9, double f10, double f11, double f12,
+     double f13, double f14, double f15;
+#else
+t_double_many_args (double f1, double f2, double f3, double f4, double f5,
+		    double f6, double f7, double f8, double f9, double f10,
+		    double f11, double f12, double f13, double f14, double f15)
+#endif
+{
+  double sum_args;
+  double sum_values;
+
+  sum_args = f1 + f2 + f3 + f4 + f5 + f6 + f7 + f8 + f9 + f10 + f11 + f12
+	     + f13 + f14 + f15;
+  sum_values = double_val1 + double_val2 + double_val3 + double_val4
+	       + double_val5 + double_val6 + double_val7 + double_val8
+	       + double_val9 + double_val10 + double_val11 + double_val12
+	       + double_val13 + double_val14 + double_val15;
+
+  return ((sum_args - sum_values) < DELTA
+	  && (sum_args - sum_values) > -DELTA);
+}
+
 #ifdef PROTOTYPES
 int t_string_values (char *string_arg1, char *string_arg2)
 #else
diff --git a/gdb/testsuite/gdb.base/callfuncs.exp b/gdb/testsuite/gdb.base/callfuncs.exp
index 7f605fd..6b53d82 100644
--- a/gdb/testsuite/gdb.base/callfuncs.exp
+++ b/gdb/testsuite/gdb.base/callfuncs.exp
@@ -155,6 +155,8 @@ proc do_function_calls {} {
         
 	gdb_test "p t_float_values2(3.14159,float_val2)" " = 1"
 
+	gdb_test "p t_float_many_args (float_val1, float_val2, float_val3, float_val4, float_val5, float_val6, float_val7, float_val8, float_val9, float_val10, float_val11, float_val12, float_val13, float_val14, float_val15)" " = 1" "Call function with many float arguments."
+
 	gdb_test "p t_small_values(1,2,3,4,5,6,7,8,9,10)" " = 55"
 
 	gdb_test "p t_double_values(0.0,0.0)" " = 0"
@@ -163,6 +165,8 @@ proc do_function_calls {} {
 	gdb_test "p t_double_values(45.654,double_val2)" " = 1"
 	gdb_test "p t_double_values(double_val1,-67.66)" " = 1"
 
+	gdb_test "p t_double_many_args (double_val1, double_val2, double_val3, double_val4, double_val5, double_val6, double_val7, double_val8, double_val9, double_val10, double_val11, double_val12, double_val13, double_val14, double_val15)" " = 1" "Call function with many double arguments."
+
 	gdb_test "p t_double_int(99.0, 1)" " = 0"
 	gdb_test "p t_double_int(99.0, 99)" " = 1"
 	gdb_test "p t_int_double(99, 1.0)" " = 0"

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Mark Kettenis]

> From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> Date: Tue, 15 Jan 2008 10:33:53 -0200
> 
> Hi,
> 
> The 64-bit PowerPC ELF ABI version 1.9 says that "single precision
> floating point values are mapped to the second word in a single
> doubleword". The ppc64_sysv_abi_push_dummy_call function in
> ppc-sysv-tdep.c, however, implements version 1.7 of the ABI which says
> that they should go in the first doubleword.

Aren't ABI changes fun?

Is the first word used for anything in the new ABI?  If not, you could
support both ABIs by copying the value into both the first and the
second word.

> Because of this, if you are calling a function with many arguments and
> some need to be passed on the stack, GDB will get it wrong for 32-bit
> floats. This is why in Linux/ppc64 GDB fails the "Call function with
> many float arguments" test posted here:
> 
> http://sourceware.org/ml/gdb-patches/2008-01/msg00291.html
> 
> This patch fixes the test. It makes GDB pass 32-bit floats in the second
> word when passing them in the stack as stated in the current ABI.
> 
> I didn't touch the code which writes the float to a general register in
> the first word because I'm not sure how to test it. It is probably
> related to soft-float, I guess.

Actually, it may be related to varargs.  Or perhaps it is a leftover
from the 32-bit ABI code that was copied.

> Tested on Linux/ppc64 with no regressions. I believe this will also fix
> other operating systems supported by GDB on ppc64 since they use the
> same push_dummy_call implementation (assuming they also follow the
> current SysV ABI), but I don't have the means to test them either.
> 
> Maybe someone could test the patch and the testcase in *BSD? Luis' patch
> which has the testcases would also need this testing.

There's no 64-bit OpenBSD/powerpc port; we only run on Apple hardware
and we run the G5 machines in 32-bit mode.

It doesn't look like NetBSD and FreeBSD have a working 64-bit powerpc
port either.

I'm fairly certain Linux/ppc64 used the old ABI for a while.  Are you
certain GDB doesn't need to support any people running those older
installs anymore?

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Jim Blandy]

Have you folks ever seen this paper?

    http://www.eecs.harvard.edu/~nr/pubs/staged-abstract.html

    We present staged allocation, a technique for specifying calling
    conventions by composing tiny allocators called stages. A
    specification written using staged allocation has a precise, formal
    semantics, and it can be executed directly inside a
    compiler. Specifications of nine standard C calling conventions range
    in size from 15 to 30 lines each. An implementation of staged
    allocation takes about 250 lines of ML or 650 lines of C++. Each
    specification can be used not only to help a compiler implement the
    calling convention but also to generate a test suite.

It seems like an interpreter for this language would take very little
effort to implement in GDB, and could save quite a bit of effort.

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

On Tue, 2008-01-15 at 15:43 +0100, Mark Kettenis wrote:
> > The 64-bit PowerPC ELF ABI version 1.9 says that "single precision
> > floating point values are mapped to the second word in a single
> > doubleword". The ppc64_sysv_abi_push_dummy_call function in
> > ppc-sysv-tdep.c, however, implements version 1.7 of the ABI which says
> > that they should go in the first doubleword.
> 
> Aren't ABI changes fun?

Heh. :-)

> Is the first word used for anything in the new ABI?  If not, you could
> support both ABIs by copying the value into both the first and the
> second word.

Great idea. I will resend the patch using that approach then.

> > Because of this, if you are calling a function with many arguments and
> > some need to be passed on the stack, GDB will get it wrong for 32-bit
> > floats. This is why in Linux/ppc64 GDB fails the "Call function with
> > many float arguments" test posted here:
> > 
> > http://sourceware.org/ml/gdb-patches/2008-01/msg00291.html
> > 
> > This patch fixes the test. It makes GDB pass 32-bit floats in the second
> > word when passing them in the stack as stated in the current ABI.
> > 
> > I didn't touch the code which writes the float to a general register in
> > the first word because I'm not sure how to test it. It is probably
> > related to soft-float, I guess.
> 
> Actually, it may be related to varargs.  Or perhaps it is a leftover
> from the 32-bit ABI code that was copied.

I'll play with varargs and see if I can trigger that code and create a
test for it.

> > Tested on Linux/ppc64 with no regressions. I believe this will also fix
> > other operating systems supported by GDB on ppc64 since they use the
> > same push_dummy_call implementation (assuming they also follow the
> > current SysV ABI), but I don't have the means to test them either.
> > 
> > Maybe someone could test the patch and the testcase in *BSD? Luis' patch
> > which has the testcases would also need this testing.
> 
> There's no 64-bit OpenBSD/powerpc port; we only run on Apple hardware
> and we run the G5 machines in 32-bit mode.
> 
> It doesn't look like NetBSD and FreeBSD have a working 64-bit powerpc
> port either.

Ok, good to know that.

> I'm fairly certain Linux/ppc64 used the old ABI for a while.  Are you
> certain GDB doesn't need to support any people running those older
> installs anymore?

No, I'm not actually...
Writing in both words should resolve this.
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

[-- Attachment #1: Type: text/plain, Size: 1062 bytes --]

On Tue, 2008-01-15 at 15:39 -0200, Thiago Jung Bauermann wrote:
> > Is the first word used for anything in the new ABI?  If not, you could
> > support both ABIs by copying the value into both the first and the
> > second word.
> 
> Great idea. I will resend the patch using that approach then.

What about this patch?

> > > I didn't touch the code which writes the float to a general register in
> > > the first word because I'm not sure how to test it. It is probably
> > > related to soft-float, I guess.
> > 
> > Actually, it may be related to varargs.  Or perhaps it is a leftover
> > from the 32-bit ABI code that was copied.
> 
> I'll play with varargs and see if I can trigger that code and create a
> test for it.

I tried it, but turns out it's not possible to pass a 32-bit float to a
variadic function, you need to explicitly promote it to double first. So
if that if code writing to a general register is not used by soft-float,
then it may be dead code as you suggested.
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

[-- Attachment #2: ppc64-abi-float-fix.diff --]
[-- Type: text/x-patch, Size: 3276 bytes --]

2008-01-15  Thiago Jung Bauermann  <bauerman@br.ibm.com>

	* ppc-sysv-tdep.c (ppc64_sysv_abi_push_dummy_call): Write 32-bit
	float in both first and second word in the doubleword, to support
	old and new ABIs.

diff --git a/gdb/ppc-sysv-tdep.c b/gdb/ppc-sysv-tdep.c
index c2952f5..466b37f 100644
--- a/gdb/ppc-sysv-tdep.c
+++ b/gdb/ppc-sysv-tdep.c
@@ -829,6 +829,7 @@ ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	  struct value *arg = args[argno];
 	  struct type *type = check_typedef (value_type (arg));
 	  const bfd_byte *val = value_contents (arg);
+
 	  if (TYPE_CODE (type) == TYPE_CODE_FLT && TYPE_LENGTH (type) <= 8)
 	    {
 	      /* Floats and Doubles go in f1 .. f13.  They also
@@ -836,40 +837,53 @@ ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	         memory.  */
 	      if (write_pass)
 		{
+		  gdb_byte regval[MAX_REGISTER_SIZE];
+		  const gdb_byte *p;
+
+		  /* Version 1.7 of the 64-bit PowerPC ELF ABI says:
+
+		     "Single precision floating point values are mapped to
+		     the first word in a single doubleword."
+
+		     And version 1.9 says:
+
+		     "Single precision floating point values are mapped to
+		     the second word in a single doubleword."
+
+		     GDB then writes single precision floating point values
+		     at both words in a doubleword, to support both ABIs.  */
+		  if (TYPE_LENGTH (type) == 4)
+		    {
+		      memcpy (regval, val, 4);
+		      memcpy (regval + 4, val, 4);
+		      p = regval;
+		    }
+		  else
+		    p = val;
+
+		  /* Write value in the stack's parameter save area.  */
+		  write_memory (gparam, p, 8);
+
 		  if (freg <= 13)
 		    {
-		      gdb_byte regval[MAX_REGISTER_SIZE];
 		      struct type *regtype
                         = register_type (gdbarch, tdep->ppc_fp0_regnum);
+
 		      convert_typed_floating (val, type, regval, regtype);
 		      regcache_cooked_write (regcache,
                                              tdep->ppc_fp0_regnum + freg,
 					     regval);
 		    }
 		  if (greg <= 10)
-		    {
-		      /* The ABI states "Single precision floating
-		         point values are mapped to the first word in
-		         a single doubleword" and "... floating point
-		         values mapped to the first eight doublewords
-		         of the parameter save area are also passed in
-		         general registers").
-
-		         This code interprets that to mean: store it,
-		         left aligned, in the general register.  */
-		      gdb_byte regval[MAX_REGISTER_SIZE];
-		      memset (regval, 0, sizeof regval);
-		      memcpy (regval, val, TYPE_LENGTH (type));
-		      regcache_cooked_write (regcache,
-					     tdep->ppc_gp0_regnum + greg,
-					     regval);
-		    }
-		  write_memory (gparam, val, TYPE_LENGTH (type));
+		    regcache_cooked_write (regcache,
+					   tdep->ppc_gp0_regnum + greg,
+					   regval);
 		}
-	      /* Always consume parameter stack space.  */
+
 	      freg++;
 	      greg++;
-	      gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
+	      /* Always consume parameter stack space.  */
+	      gparam = align_up (gparam + 8, tdep->wordsize);
 	    }
 	  else if (TYPE_CODE (type) == TYPE_CODE_FLT
 		   && TYPE_LENGTH (type) == 16

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Mark Kettenis]

> From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> Date: Tue, 15 Jan 2008 18:33:54 -0200
> 
> On Tue, 2008-01-15 at 15:39 -0200, Thiago Jung Bauermann wrote:
> > > Is the first word used for anything in the new ABI?  If not, you could
> > > support both ABIs by copying the value into both the first and the
> > > second word.
> > 
> > Great idea. I will resend the patch using that approach then.
> 
> What about this patch?

Looks fine to me, but I have no means to test it.

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

On Tue, 2008-01-15 at 21:48 +0100, Mark Kettenis wrote:
> > From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> > Date: Tue, 15 Jan 2008 18:33:54 -0200
> > 
> > On Tue, 2008-01-15 at 15:39 -0200, Thiago Jung Bauermann wrote:
> > > > Is the first word used for anything in the new ABI?  If not, you could
> > > > support both ABIs by copying the value into both the first and the
> > > > second word.
> > > 
> > > Great idea. I will resend the patch using that approach then.
> > 
> > What about this patch?
> 
> Looks fine to me, but I have no means to test it.

This is tested in Linux/ppc64.
I'll check this version for regressions (I only regtested the previous
patch).
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

On Tue, 2008-01-15 at 18:54 -0200, Thiago Jung Bauermann wrote:
> On Tue, 2008-01-15 at 21:48 +0100, Mark Kettenis wrote:
> > > From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> > > Date: Tue, 15 Jan 2008 18:33:54 -0200
> > > 
> > > On Tue, 2008-01-15 at 15:39 -0200, Thiago Jung Bauermann wrote:
> > > > > Is the first word used for anything in the new ABI?  If not, you could
> > > > > support both ABIs by copying the value into both the first and the
> > > > > second word.
> > > > 
> > > > Great idea. I will resend the patch using that approach then.
> > > 
> > > What about this patch?
> > 
> > Looks fine to me, but I have no means to test it.
> 
> This is tested in Linux/ppc64.
> I'll check this version for regressions (I only regtested the previous
> patch).

No regressions found. Ok to commit?
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Luis Machado]

On Wed, 2008-01-16 at 10:48 -0200, Thiago Jung Bauermann wrote:
> On Tue, 2008-01-15 at 18:54 -0200, Thiago Jung Bauermann wrote:
> > On Tue, 2008-01-15 at 21:48 +0100, Mark Kettenis wrote:
> > > > From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> > > > Date: Tue, 15 Jan 2008 18:33:54 -0200
> > > > 
> > > > On Tue, 2008-01-15 at 15:39 -0200, Thiago Jung Bauermann wrote:
> > > > > > Is the first word used for anything in the new ABI?  If not, you could
> > > > > > support both ABIs by copying the value into both the first and the
> > > > > > second word.
> > > > > 
> > > > > Great idea. I will resend the patch using that approach then.
> > > > 
> > > > What about this patch?
> > > 
> > > Looks fine to me, but I have no means to test it.
> > 
> > This is tested in Linux/ppc64.
> > I'll check this version for regressions (I only regtested the previous
> > patch).
> 
> No regressions found. Ok to commit?

Maybe adding the testcase and the 32-bit fix as well?

-- 
Luis Machado
Software Engineer 
IBM Linux Technology Center

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

On Wed, 2008-01-16 at 10:48 -0200, Thiago Jung Bauermann wrote:
> On Tue, 2008-01-15 at 18:54 -0200, Thiago Jung Bauermann wrote:
> > On Tue, 2008-01-15 at 21:48 +0100, Mark Kettenis wrote:
> > > > From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> > > > Date: Tue, 15 Jan 2008 18:33:54 -0200
> > > > 
> > > > On Tue, 2008-01-15 at 15:39 -0200, Thiago Jung Bauermann wrote:
> > > > > > Is the first word used for anything in the new ABI?  If not, you could
> > > > > > support both ABIs by copying the value into both the first and the
> > > > > > second word.
> > > > > 
> > > > > Great idea. I will resend the patch using that approach then.
> > > > 
> > > > What about this patch?
> > > 
> > > Looks fine to me, but I have no means to test it.
> > 
> > This is tested in Linux/ppc64.
> > I'll check this version for regressions (I only regtested the previous
> > patch).
> 
> No regressions found. Ok to commit?

Ping?

I found an older Linux system here (from 2003 or 2004), and its GDB
implements the 1.7 ABI but still fails the test with many float
arguments, which means the 1.9 ABI is already in use.

Since current GDB CVS doesn't compile in that system anymore (actually
compilation failed in the bfd library), it also won't compile in an even
older system which would use the 1.7 ABI. Because of this, we shouldn't
worry too much about supporting the older ABI I think.

Still, my patch preserves compatibility with the 1.7 ABI while
implementing the 1.9 version. It's just that I wasn't able to test this
compatibility.
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

On Fri, 2008-01-25 at 13:45 -0200, Thiago Jung Bauermann wrote:
> I found an older Linux system here (from 2003 or 2004), and its GDB
> implements the 1.7 ABI but still fails the test with many float
> arguments, which means the 1.9 ABI is already in use.
> 
> Since current GDB CVS doesn't compile in that system anymore (actually
> compilation failed in the bfd library)

For the record:

$ gdb --version
GNU gdb Red Hat Linux (6.3.0.0-1.138.el3rh)

$ gcc --version
gcc (GCC) 3.2.3 20030502 (Red Hat Linux 3.2.3-59)

$ /lib/libc.so.6
GNU C Library stable release version 2.3.2, by Roland McGrath et al.

$ uname -srm
Linux 2.4.21-52.EL ppc64

-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Daniel Jacobowitz]

On Fri, Jan 25, 2008 at 01:45:30PM -0200, Thiago Jung Bauermann wrote:
> On Wed, 2008-01-16 at 10:48 -0200, Thiago Jung Bauermann wrote:
> > On Tue, 2008-01-15 at 18:54 -0200, Thiago Jung Bauermann wrote:
> > > On Tue, 2008-01-15 at 21:48 +0100, Mark Kettenis wrote:
> > > > Looks fine to me, but I have no means to test it.

> Ping?

I think Mark's already approved this one, above - just in case he
hasn't, I will too.  Go ahead.

-- 
Daniel Jacobowitz
CodeSourcery

Re: [RFA] Fix float argument passing in inferior function calls for ppc64

[Thiago Jung Bauermann]

On Thu, 2008-01-31 at 17:06 -0500, Daniel Jacobowitz wrote:
> On Fri, Jan 25, 2008 at 01:45:30PM -0200, Thiago Jung Bauermann wrote:
> > On Wed, 2008-01-16 at 10:48 -0200, Thiago Jung Bauermann wrote:
> > > On Tue, 2008-01-15 at 18:54 -0200, Thiago Jung Bauermann wrote:
> > > > On Tue, 2008-01-15 at 21:48 +0100, Mark Kettenis wrote:
> > > > > Looks fine to me, but I have no means to test it.
> 
> > Ping?
> 
> I think Mark's already approved this one, above - just in case he
> hasn't, I will too.  Go ahead.

Yeah, I wasn't sure if it was approved. Committed now, thanks.
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center