* sh-tdep.c (sh_use_struct_convention): Clean up to have a

	more readable code.  Accomodate passing of bitfields.

2 files changed, 29 insertions, 2 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 41f7dfe..d170797 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2003-10-10  Corinna Vinschen  <vinschen@redhat.com>
+
+	* sh-tdep.c (sh_use_struct_convention): Clean up to have a
+	more readable code.  Accomodate passing of bitfields.
+
 2003-10-10  Andrew Cagney  <cagney@redhat.com>
 
 	* Makefile.in (ppc-sysv-tdep.o): Add $(gdb_assert_h).
diff --git a/gdb/sh-tdep.c b/gdb/sh-tdep.c
index a220493..eee7698 100644
--- a/gdb/sh-tdep.c
+++ b/gdb/sh-tdep.c
@@ -589,8 +589,30 @@ sh_use_struct_convention (int gcc_p, struct type *type)
 {
   int len = TYPE_LENGTH (type);
   int nelem = TYPE_NFIELDS (type);
-  return ((len != 1 && len != 2 && len != 4 && len != 8) || nelem != 1) &&
-    (len != 8 || TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) != 4);
+
+  /* Non-power of 2 length types and types bigger than 8 bytes (which don't
+     fit in two registers anyway) use struct convention.  */
+  if (len != 1 && len != 2 && len != 4 && len != 8)
+    return 1;
+
+  /* Scalar types and aggregate types with exactly one field are aligned
+     by definition.  They are returned in registers.  */
+  if (nelem <= 1)
+    return 0;
+
+  /* If the first field in the aggregate has the same length as the entire
+     aggregate type, the type is returned in registers.  */
+  if (TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) == len)
+    return 0;
+
+  /* If the size of the aggregate is 8 bytes and the first field is
+     of size 4 bytes its alignment is equal to long long's alignment,
+     so it's returned in registers.  */
+  if (len == 8 && TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) == 4)
+    return 0;
+
+  /* Otherwise use struct convention.  */
+  return 1;
 }
 
 /* Extract from an array REGBUF containing the (raw) register state