RE: [PATCH - h8300] function_vector attribute in H8300 targets

["Asgari J. Jinia" <AsgariJ at KPITCummins dot com>]

Hi Kazu,

Once again thanks for your valuable feedback.

> Please use || instead of |.
Done.
Although it doesn't affect functionality but using || instead of | is better.

> Do we really need "& 0xff"?  See the range check issue below.
Ok. I have put this check while doing attribute validation.
> Please use CONST_INT instead of XINT.
Done.

> You might want to check if the argument is in range between 0 and 255
> and reject those that are out of range.
Done.

> You might want to mention that vector_address must be an 
> integer constant.
Done.

> You might want to replace vector_address with some integer constant if
> function_vector only accepts integer constants.  Otherwise, the user
> may get confused as to what function_vector takes as its argument.
Done.

Attached patch is for mainline.

ChangeLog:
2004-09-24  Asgari Jinia <ajinia@kpitcummins.com>
	* config/h8300/h8300.c (h8300_handle_function_vector_attribute): New function.
      (print_operand): New switch case added to check jsr operands.
      (h8300_attrib): Changed for argument and new function.
	* config/h8300/h8300.md (call): Changed assembly output to get processed by
      print_operand function.
      (call_value): Likewise.
	* doc/extend.texi (function_vector): changed description.
	* testsuite/gcc.dg/func-vect.c: New test for function vector attribute.

--- gcc-3.4.2/gcc/config/h8300/h8300.c.orig	2004-02-09 22:55:35.000000000 +0530
+++ gcc-3.4.2/gcc/config/h8300/h8300.c	2004-09-28 13:20:58.000000000 +0530
@@ -61,6 +61,7 @@ static const char *cond_string (enum rtx
 static unsigned int h8300_asm_insn_count (const char *);
 static tree h8300_handle_fndecl_attribute (tree *, tree, tree, int, bool *);
 static tree h8300_handle_eightbit_data_attribute (tree *, tree, tree, int, bool *);
+static tree h8300_handle_function_vector_attribute (tree *, tree, tree, int, bool *);
 static tree h8300_handle_tiny_data_attribute (tree *, tree, tree, int, bool *);
 #ifndef OBJECT_FORMAT_ELF
 static void h8300_asm_named_section (const char *, unsigned int);
@@ -1127,6 +1128,7 @@ h8300_rtx_costs (rtx x, int code, int ou
 
 /* Documentation for the machine specific operand escapes:
 
+   'C' print jsr operand
    'E' like s but negative.
    'F' like t but negative.
    'G' constant just the negative
@@ -1198,6 +1200,53 @@ print_operand (FILE *file, rtx x, int co
 
   switch (code)
     {
+    case 'C':
+      switch (GET_CODE (x))
+    {
+    case MEM:
+    {
+      rtx inside = XEXP (x, 0);
+      if (GET_CODE (inside) == SYMBOL_REF
+          && (SYMBOL_REF_FLAGS (inside) & SYMBOL_FLAG_FUNCVEC_FUNCTION))
+        {
+            int func_vect_num;
+            tree t;
+            t = SYMBOL_REF_DECL (inside);
+            
+            func_vect_num = TREE_INT_CST_LOW (TREE_VALUE (TREE_VALUE (lookup_attribute ("function_vector",
+                                                                      DECL_ATTRIBUTES (t)))));
+            fprintf (file,"@%d:8",func_vect_num);
+        }
+      else if (GET_CODE (inside) == SYMBOL_REF)
+        {
+            assemble_name (file,XSTR (inside,0));
+        }
+      else if (GET_CODE (inside) == REG)
+        {
+            if (TARGET_H8300)
+              fprintf (file, "%s", names_big[REGNO (inside)]);
+            else
+              fprintf (file, "%s", names_extended[REGNO (inside)]);
+        }
+      else if (GET_CODE (inside) == CONST_INT)
+        {
+            if (TARGET_H8300 || TARGET_NORMAL_MODE)
+              fprintf (file, "%d", INTVAL (inside) & 0xffff);
+            else
+              fprintf (file, "%d", INTVAL (inside) & 0xffffff);
+        }
+      else
+        {
+            print_operand_address (file, inside);                
+        }
+        
+
+    }
+      break;
+    default:
+      abort ();
+    }
+      break;    
     case 'E':
       switch (GET_CODE (x))
 	{
@@ -4240,7 +4289,7 @@ const struct attribute_spec h8300_attrib
   { "saveall",           0, 0, true,  false, false, h8300_handle_fndecl_attribute },
   { "OS_Task",           0, 0, true,  false, false, h8300_handle_fndecl_attribute },
   { "monitor",           0, 0, true,  false, false, h8300_handle_fndecl_attribute },
-  { "function_vector",   0, 0, true,  false, false, h8300_handle_fndecl_attribute },
+  { "function_vector",   1, 1, true,  false, false, h8300_handle_function_vector_attribute },
   { "eightbit_data",     0, 0, true,  false, false, h8300_handle_eightbit_data_attribute },
   { "tiny_data",         0, 0, true,  false, false, h8300_handle_tiny_data_attribute },
   { NULL,                0, 0, false, false, false, NULL }
@@ -4264,6 +4313,39 @@ h8300_handle_fndecl_attribute (tree *nod
 
   return NULL_TREE;
 }
+/* Handle a "function_vector" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+h8300_handle_function_vector_attribute (tree *node, tree name,
+                   tree args ATTRIBUTE_UNUSED,
+                   int flags ATTRIBUTE_UNUSED,
+                   bool *no_add_attrs)
+{
+  if (TREE_CODE (*node) != FUNCTION_DECL)
+    {
+      warning ("`%s' attribute only applies to functions",
+           IDENTIFIER_POINTER (name));
+      *no_add_attrs = true;
+    }
+  else if (TREE_CODE (TREE_VALUE (args)) != INTEGER_CST)
+    {
+      /* The argument must be a constant integer.  */
+      warning ("`%s' attribute argument not an integer constant",
+           IDENTIFIER_POINTER (name));
+      *no_add_attrs = true;
+    }
+  else if (TREE_INT_CST_LOW (TREE_VALUE (args)) > 255)
+    {
+      /* The argument must be within 0-255  */
+      warning ("`%s' attribute argument must be in range between 0 and 255",
+           IDENTIFIER_POINTER (name));
+      *no_add_attrs = true;
+    }
+  
+  return NULL_TREE;
+}
+
 
 /* Handle an "eightbit_data" attribute; arguments as in
    struct attribute_spec.handler.  */


--- gcc-3.4.2/gcc/config/h8300/h8300.md.orig	2004-09-28 14:30:07.000000000 +0530
+++ gcc-3.4.2/gcc/config/h8300/h8300.md	2004-09-28 14:30:17.000000000 +0530
@@ -1816,14 +1816,7 @@
   [(call (match_operand:QI 0 "call_insn_operand" "or")
 	 (match_operand:HI 1 "general_operand" "g"))]
   ""
-  "*
-{
-  if (GET_CODE (XEXP (operands[0], 0)) == SYMBOL_REF
-      && SYMBOL_REF_FLAG (XEXP (operands[0], 0)))
-    return \"jsr\\t@%0:8\";
-  else
-    return \"jsr\\t%0\";
-}"
+  "jsr	@%C0"
   [(set_attr "cc" "clobber")
    (set (attr "length")
 	(if_then_else (match_operand:QI 0 "small_call_insn_operand" "")
@@ -1840,14 +1833,7 @@
 	(call (match_operand:QI 1 "call_insn_operand" "or")
 	      (match_operand:HI 2 "general_operand" "g")))]
   ""
-  "*
-{
-  if (GET_CODE (XEXP (operands[1], 0)) == SYMBOL_REF
-      && SYMBOL_REF_FLAG (XEXP (operands[1], 0)))
-    return \"jsr\\t@%1:8\";
-  else
-    return \"jsr\\t%1\";
-}"
+  "jsr	@%C1"
   [(set_attr "cc" "clobber")
    (set (attr "length")
 	(if_then_else (match_operand:QI 0 "small_call_insn_operand" "")

--- gcc-3.4.2/gcc/doc/extend.texi.orig	2004-09-28 14:34:53.000000000 +0530
+++ gcc-3.4.2/gcc/doc/extend.texi	2004-09-28 14:38:25.000000000 +0530
@@ -2486,13 +2486,33 @@ contents of that register.   The @code{s
 the offset to the function from the call site into the @samp{BL}
 instruction directly.
 
-@item function_vector
+@item function_vector (@var{vector_address})
 @cindex calling functions through the function vector on the H8/300 processors
 Use this attribute on the H8/300, H8/300H, and H8S to indicate that the specified
 function should be called through the function vector.  Calling a
 function through the function vector will reduce code size, however;
 the function vector has a limited size (maximum 128 entries on the H8/300
 and 64 entries on the H8/300H and H8S) and shares space with the interrupt vector.
+The "@var{vector_address}" is integer constant in the range from 0 to 255.
+
+Compiler uses 2 bytes instead of 4 bytes to call a function declared with this
+attribute. For this compiler uses memory indirect call using jsr @@aa:8 instruction.
+
+For example, following call to "foo" will use 2 bytes instead of 4 bytes. Compiler
+will use jsr @@16:8 instruction to call "foo". Also ensure that address of "foo"
+must be present at location 0x10.
+
+@smallexample
+void foo (void) __attribute__ ((function_vector(0x10)));
+void foo (void)
+@{
+@}
+
+void bar (void)
+@{
+    foo();
+@}
+@end smallexample
 
 You must use GAS and GLD from GNU binutils version 2.7 or later for
 this attribute to work correctly.


--- /dev/null	2002-08-31 05:01:37.000000000 +0530
+++ gcc-3.4.2/gcc/testsuite/gcc.dg/func-vect.c	2004-09-22 13:07:31.000000000 +0530
@@ -0,0 +1,15 @@
+/* Test for function_vector attribute.  */
+/* Origin: Asgari Jinia <asgarij@kpitcummins.com> */
+/* { dg-do compile {target h8300*-*-*}} */
+/* { dg-final { scan-assembler "jsr\t@@16:8" } } */
+
+void foo(void) __attribute__((function_vector(16)));
+void foo(void)
+{
+
+}
+
+void bar(void)
+{
+    foo();
+}


Best Regards,
Asgari Jinia
KPIT Cummins InfoSystems Ltd.
Pune, India

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Attachment: function_vector_mainline.patch
Description: function_vector_mainline.patch