check for invalid Xtensa instructions

[Bob Wilson <bwilson at tensilica dot com>]

I've committed this patch to check for Xtensa instructions that are invalid 
because they contain more than one access to hardware interfaces that are 
related (e.g., for hardware queues).


2004-11-12  Bob Wilson  <bob.wilson@acm.org>

include/ChangeLog
	* xtensa-isa-internal.h (xtensa_interface_internal): Add class_id.
	* xtensa-isa.h (xtensa_interface_class_id): New prototype.

bfd/ChangeLog
	* xtensa-isa.c (xtensa_interface_class_id): New.

gas/ChangeLog
	* config/tc-xtensa.c (finish_vinsn): Clear pending instruction if
	there is a conflict.
	(check_t1_t2_reads_and_writes): Check for both reads and writes to
	interfaces that are related as determined by xtensa_interface_class_id.

Index: include/xtensa-isa-internal.h
===================================================================
RCS file: /cvs/src/src/include/xtensa-isa-internal.h,v
retrieving revision 1.3
diff -u -p -r1.3 xtensa-isa-internal.h
--- include/xtensa-isa-internal.h	8 Oct 2004 00:22:12 -0000	1.3
+++ include/xtensa-isa-internal.h	12 Nov 2004 21:40:08 -0000
@@ -131,6 +131,7 @@ typedef struct xtensa_interface_internal
   const char *name;			/* Interface name.  */
   int num_bits;				/* Width of the interface.  */
   uint32 flags;				/* See XTENSA_INTERFACE_* flags.  */
+  int class_id;				/* Class of related interfaces.  */
   char inout;				/* "i" or "o".  */
 } xtensa_interface_internal;
 
Index: include/xtensa-isa.h
===================================================================
RCS file: /cvs/src/src/include/xtensa-isa.h,v
retrieving revision 1.2
diff -u -p -r1.2 xtensa-isa.h
--- include/xtensa-isa.h	8 Oct 2004 00:22:12 -0000	1.2
+++ include/xtensa-isa.h	12 Nov 2004 21:40:08 -0000
@@ -755,6 +755,19 @@ xtensa_interface_inout (xtensa_isa isa, 
 extern int
 xtensa_interface_has_side_effect (xtensa_isa isa, xtensa_interface intf);
 
+
+/* Some interfaces may be related such that accessing one interface
+   has side effects on a set of related interfaces.  The interfaces
+   are partitioned into equivalence classes of related interfaces, and
+   each class is assigned a unique identifier number.  This function
+   returns the class identifier for an interface, or XTENSA_UNDEFINED
+   on error.  These identifiers can be compared to determine if two
+   interfaces are related; the specific values of the identifiers have
+   no particular meaning otherwise.  */
+
+extern int
+xtensa_interface_class_id (xtensa_isa isa, xtensa_interface intf);
+
 
 /* Functional Units.  */
 
Index: bfd/xtensa-isa.c
===================================================================
RCS file: /cvs/src/src/bfd/xtensa-isa.c,v
retrieving revision 1.3
diff -u -p -r1.3 xtensa-isa.c
--- bfd/xtensa-isa.c	8 Oct 2004 00:22:10 -0000	1.3
+++ bfd/xtensa-isa.c	12 Nov 2004 21:40:08 -0000
@@ -1677,6 +1677,15 @@ xtensa_interface_has_side_effect (xtensa
   return 0;
 }
 
+
+int
+xtensa_interface_class_id (xtensa_isa isa, xtensa_interface intf)
+{
+  xtensa_isa_internal *intisa = (xtensa_isa_internal *) isa;
+  CHECK_INTERFACE (intisa, intf, XTENSA_UNDEFINED);
+  return intisa->interfaces[intf].class_id;
+}
+
 
 /* Functional Units.  */
 
Index: gas/config/tc-xtensa.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-xtensa.c,v
retrieving revision 1.17
diff -u -p -r1.17 tc-xtensa.c
--- gas/config/tc-xtensa.c	11 Nov 2004 19:05:41 -0000	1.17
+++ gas/config/tc-xtensa.c	12 Nov 2004 21:40:09 -0000
@@ -6013,7 +6013,7 @@ opcode_funcUnit_use_stage (void *data, x
    solely whether the hardware is available to execute the given
    instructions together.  It also doesn't check if the tinsns 
    write the same state, or access the same tieports.  That is
-   checked by check_t1_t2_read_write.  */
+   checked by check_t1_t2_reads_and_writes.  */
 
 static bfd_boolean
 resources_conflict (vliw_insn *vinsn)
@@ -6069,7 +6069,10 @@ finish_vinsn (vliw_insn *vinsn)
   int line;
 
   if (find_vinsn_conflicts (vinsn))
-    return;
+    {
+      xg_clear_vinsn (vinsn);
+      return;
+    }
 
   /* First, find a format that works.  */
   if (vinsn->format == XTENSA_UNDEFINED)
@@ -6326,7 +6329,7 @@ find_vinsn_conflicts (vliw_insn *vinsn)
 }
 
 
-/* Check how the result registers of t1 and t2 relate.
+/* Check how the state used by t1 and t2 relate.
    Cases found are:
 
    case A: t1 reads a register t2 writes (an antidependency within a bundle)
@@ -6336,7 +6339,7 @@ find_vinsn_conflicts (vliw_insn *vinsn)
            bundle)
    case D: t1 writes a state that t2 also writes
    case E: t1 writes a tie queue that t2 also writes
-   case F: two volatile queue writes
+   case F: two volatile queue accesses
 */
 
 static char
@@ -6459,18 +6462,24 @@ check_t1_t2_reads_and_writes (TInsn *t1,
     {
       xtensa_interface t2_int
 	= xtensa_interfaceOperand_interface (isa, t2->opcode, j);
+      int t2_class = xtensa_interface_class_id (isa, t2_int);
+
       t2_inout = xtensa_interface_inout (isa, j);
-      if (xtensa_interface_has_side_effect (isa, t2_int) == 1 
-	  && t2_inout != 'i')
+      if (xtensa_interface_has_side_effect (isa, t2_int) == 1)
 	t2_volatile = TRUE;
+
       for (i = 0; i < t1_interfaces; i++)
 	{
 	  xtensa_interface t1_int
 	    = xtensa_interfaceOperand_interface (isa, t1->opcode, j);
+	  int t1_class = xtensa_interface_class_id (isa, t2_int);
+
 	  t1_inout = xtensa_interface_inout (isa, i);
-	  if (xtensa_interface_has_side_effect (isa, t1_int) == 1 
-	      && t1_inout != 'i')
+	  if (xtensa_interface_has_side_effect (isa, t1_int) == 1)
 	    t1_volatile = TRUE;
+
+	  if (t1_volatile && t2_volatile && (t1_class == t2_class))
+	    return 'f';
 	  
 	  if (t1_int != t2_int)
 	    continue;
@@ -6491,9 +6500,6 @@ check_t1_t2_reads_and_writes (TInsn *t1,
 	    return 'e';
 	}
     }
-
-  if (t1_volatile && t2_volatile)
-    return 'f';
   
   return conflict;
 }