[Patch] Fix ABI incompatibilities on s390x

[Gerhard Tonn <ton at de dot ibm dot com>]

Hi,
attached is a patch that fixes some ABI incompatibilities for the s390x
architecture.

2002-11-19  Gerhard Tonn  <ton@de.ibm.com>

	* s390-tdep.c (s390_push_arguments, s390_get_frame_info):              
	   Fix the s390x ELF ABI implementation bugs.

--- gdb-5.2.cvs20020401/gdb/s390-tdep.c	Mon Apr  1 03:09:43 2002
+++ gdb-5.2.cvs20020401-new/gdb/s390-tdep.c	Fri Jul 26 11:53:57 2002
@@ -95,6 +95,8 @@
 #define S390_UC_MCONTEXT_OFFSET    (256)
 #define S390X_UC_MCONTEXT_OFFSET   (344)
 #define S390_STACK_FRAME_OVERHEAD  (GDB_TARGET_IS_ESAME ? 160:96)
+#define S390_STACK_PARAMETER_ALIGNMENT  (GDB_TARGET_IS_ESAME ? 8:4)
+#define S390_NUM_FP_PARAMETER_REGISTERS (GDB_TARGET_IS_ESAME ? 4:2)
 #define S390_SIGNAL_FRAMESIZE  (GDB_TARGET_IS_ESAME ? 160:96)
 #define s390_NR_sigreturn          119
 #define s390_NR_rt_sigreturn       173
@@ -1378,9 +1380,9 @@
 
   /* This is almost a direct translation of the ABI's language, except
      that we have to exclude 8-byte structs; those are DOUBLE_ARGs.  */
-  return ((is_integer_like (type) && length <= 4)
+  return ((is_integer_like (type) && length <= REGISTER_SIZE)
           || is_pointer_like (type)
-          || (is_struct_like (type) && length != 8)
+          || (is_struct_like (type) && (GDB_TARGET_IS_ESAME ? 1 : length != 8))
           || (is_float_like (type) && length == 16));
 }
 
@@ -1393,7 +1395,8 @@
 {
   unsigned length = TYPE_LENGTH (type);
 
-  return ((is_struct_like (type) && length != 1 && length != 2 && length != 4)
+  return ((is_struct_like (type) && length != 1 && length != 2 && length != 4
+           && (GDB_TARGET_IS_ESAME ? length != 8 : 1))
           || (is_float_like (type) && length == 16));
 }
 
@@ -1551,9 +1554,9 @@
         
         sp = round_down (sp, alignment_of (type));
 
-        /* SIMPLE_ARG values get extended to 32 bits.  Assume every
-           argument is.  */
-        if (length < 4) length = 4;
+        /* SIMPLE_ARG values get extended to REGISTER_SIZE bytes. 
+           Assume every argument is.  */
+        if (length < REGISTER_SIZE) length = REGISTER_SIZE;
         sp -= length;
       }
   }
@@ -1574,13 +1577,17 @@
     int gr = 2;
     CORE_ADDR starg = sp;
 
+    /* A struct is returned using general register 2 */
+    if (struct_return)
+      gr++;
+
     for (i = 0; i < nargs; i++)
       {
         struct value *arg = args[i];
         struct type *type = VALUE_TYPE (arg);
         
         if (is_double_or_float (type)
-            && fr <= 2)
+            && fr <= S390_NUM_FP_PARAMETER_REGISTERS * 2 - 2)
           {
             /* When we store a single-precision value in an FP register,
                it occupies the leftmost bits.  */
@@ -1601,13 +1608,13 @@
 
             gr++;
           }
-        else if (is_double_arg (type)
+        else if (!GDB_TARGET_IS_ESAME && is_double_arg (type)
                  && gr <= 5)
           {
             write_register_gen (S390_GP0_REGNUM + gr,
                                 VALUE_CONTENTS (arg));
             write_register_gen (S390_GP0_REGNUM + gr + 1,
-                                VALUE_CONTENTS (arg) + 4);
+                                VALUE_CONTENTS (arg) + REGISTER_SIZE);
             gr += 2;
           }
         else
@@ -1618,14 +1625,14 @@
             
             /* If we skipped r6 because we couldn't fit a DOUBLE_ARG
                in it, then don't go back and use it again later.  */
-            if (is_double_arg (type) && gr == 6)
+            if (!GDB_TARGET_IS_ESAME && is_double_arg (type) && gr == 6)
               gr = 7;
 
             if (is_simple_arg (type))
               {
-                /* Simple args are always either extended to 32 bits,
-                   or pointers.  */
-                starg = round_up (starg, 4);
+                /* Simple args are always extended to 
+                   REGISTER_SIZE bytes.  */
+                starg = round_up (starg, REGISTER_SIZE);
 
                 /* Do we need to pass a pointer to our copy of this
                    argument?  */
@@ -1633,18 +1640,19 @@
                   write_memory_signed_integer (starg, pointer_size,
                                                copy_addr[i]);
                 else
-                  /* Simple args are always extended to 32 bits.  */
-                  write_memory_signed_integer (starg, 4,
+                  /* Simple args are always extended to 
+                     REGISTER_SIZE bytes. */
+                  write_memory_signed_integer (starg, REGISTER_SIZE,
                                                extend_simple_arg (arg));
-                starg += 4;
+                starg += REGISTER_SIZE;
               }
             else
               {
                 /* You'd think we should say:
                    starg = round_up (starg, alignment_of (type));
                    Unfortunately, GCC seems to simply align the stack on
-                   a four-byte boundary, even when passing doubles.  */
-                starg = round_up (starg, 4);
+                   a four/eight-byte boundary, even when passing doubles. */
+                starg = round_up (starg, S390_STACK_PARAMETER_ALIGNMENT);
                 write_memory (starg, VALUE_CONTENTS (arg), length);
                 starg += length;
               }
@@ -1655,7 +1663,7 @@
   /* Allocate the standard frame areas: the register save area, the
      word reserved for the compiler (which seems kind of meaningless),
      and the back chain pointer.  */
-  sp -= 96;
+  sp -= S390_STACK_FRAME_OVERHEAD;
 
   /* Write the back chain pointer into the first word of the stack
      frame.  This will help us get backtraces from within functions


--
Regards,
Gerhard