[commit] Wrong return convention for arrays (mips-irix)

[Joel Brobecker <brobecker at adacore dot com>]

Consider the following function returning an array whose size is
128 bits or smaller:  
 
    type Data_Small is array (1 .. 2) of Integer;
    function Create_Small return Data_Small;

GDB claims that the return value cannot be printed at the end of
a "finish":

    (gdb) break create_small
    Breakpoint 1 at 0x10002954: file pck.adb, line 5. 
    (gdb) run
    Starting program: /[...]/p

    Breakpoint 1, pck.create_small () at pck.adb:5
    5             return (others => 1);
    (gdb) finish
    Run till exit from #0  pck.create_small () at pck.adb:5
    0x10002bdc in p () at p.adb:8
    8          Small := Create_Small;
    Value returned has type: pck__data_small. Cannot determine contents

The problem comes from mips-tdep.c:mips_n32n64_return_value which
considers that arrays are always returned using the
RETURN_VALUE_STRUCT_CONVENTION.  But in fact, this is not entirely
correct. Looking at the ABI, all composite types that are 128bits
or smaller are returned via $2 and $3 (except for the special case
of a struct containing one or two floats).

This patch modifies the logic accordingly.

gdb/ChangeLog:

        Wrong return convention for arrays (mips-irix).
        * mips-tdep.c (mips_n32n64_return_value): Arrays whose size is
        128 bits or smaller are returned the same way as structs
        and unions of the the same size.

-- 
Joel

gdb/ChangeLog:

        Wrong return convention for arrays (mips-irix).
        * mips-tdep.c (mips_n32n64_return_value): Arrays whose size is
        128 bits or smaller are returned the same way as structs
        and unions of the the same size.
---
 gdb/mips-tdep.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 92fcd4a..6749c27 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -3379,7 +3379,7 @@ mips_n32n64_return_value (struct gdbarch *gdbarch, struct type *func_type,
      (and $f2 if necessary).  This is a generalization of the Fortran COMPLEX
      case.
 
-     * Any other struct or union results of at most 128 bits are returned in
+     * Any other composite results of at most 128 bits are returned in
      $2 (first 64 bits) and $3 (remainder, if necessary).
 
      * Larger composite results are handled by converting the function to a
@@ -3390,8 +3390,7 @@ mips_n32n64_return_value (struct gdbarch *gdbarch, struct type *func_type,
      specific exception to return COMPLEX results in the floating point
      registers.]  */
 
-  if (TYPE_CODE (type) == TYPE_CODE_ARRAY
-      || TYPE_LENGTH (type) > 2 * MIPS64_REGSIZE)
+  if (TYPE_LENGTH (type) > 2 * MIPS64_REGSIZE)
     return RETURN_VALUE_STRUCT_CONVENTION;
   else if (TYPE_CODE (type) == TYPE_CODE_FLT
 	   && TYPE_LENGTH (type) == 16
@@ -3481,9 +3480,10 @@ mips_n32n64_return_value (struct gdbarch *gdbarch, struct type *func_type,
       return RETURN_VALUE_REGISTER_CONVENTION;
     }
   else if (TYPE_CODE (type) == TYPE_CODE_STRUCT
-	   || TYPE_CODE (type) == TYPE_CODE_UNION)
+	   || TYPE_CODE (type) == TYPE_CODE_UNION
+	   || TYPE_CODE (type) == TYPE_CODE_ARRAY)
     {
-      /* A structure or union.  Extract the left justified value,
+      /* A composite type.  Extract the left justified value,
          regardless of the byte order.  I.e. DO NOT USE
          mips_xfer_lower.  */
       int offset;
-- 
1.5.4.3