Patchwork Commit: RX: Warn about multiple fast interrupt routines.

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Submitter Nick Clifton
Date Oct. 3, 2012, 4:05 p.m.
Message ID <87y5jnr177.fsf@redhat.com>
Download mbox | patch
Permalink /patch/188821/
State New
Headers show

Comments

Nick Clifton - Oct. 3, 2012, 4:05 p.m.
Hi Guys,

  I am applying the patch below to the RX backend.  It adds support for
  issuing warning messages when multiple fast interrupt routines are
  defined in the same compilation unit.  The RX only supports one fast
  interrupt so it is probably a mistake to define more than one.  If the
  programmer really does want to define them then the command line
  -mno-warn-multiple-fast-interrupts can be used.  Of course it is
  possible to define multiple fast interrupt handlers in multiple
  compilation units and then link them together, but Renesas were not
  interested in solving this problem.

Cheers
  Nick

PS.  I have even remembered to include a patch to the html documentation
as well!


gcc/ChangeLog
2012-10-03  Nick Clifton  <nickc@redhat.com>

	* config/rx/rx.c (struct decl_chain): New local structure.
	(warned_decls): New local variable.  Contains a stack of decls for
	which warnings have been issued.
	(add_warned_decl): Adds a decl to the stack.
	(already_warned): Returns true if a given decl is on the stack.
	(rx_set_current_function): Issue a warning if multiple fast
	interrupt handlers are defined.
	* config/rx/rx.opt (mwarn-multiple-fast-interrupts): New option.
	* doc/invoke.texi: Document the option.

Patch

Index: gcc/config/rx/rx.c
===================================================================
--- gcc/config/rx/rx.c	(revision 192034)
+++ gcc/config/rx/rx.c	(working copy)
@@ -1256,6 +1256,41 @@ 
     }
 }
 
+struct decl_chain
+{
+  tree fndecl;
+  struct decl_chain * next;
+};
+
+/* Stack of decls for which we have issued warnings.  */
+static struct decl_chain * warned_decls = NULL;
+
+static void
+add_warned_decl (tree fndecl)
+{
+  struct decl_chain * warned = (struct decl_chain *) xmalloc (sizeof * warned);
+
+  warned->fndecl = fndecl;
+  warned->next = warned_decls;
+  warned_decls = warned;
+}
+
+/* Returns TRUE if FNDECL is on our list of warned about decls.  */
+
+static bool
+already_warned (tree fndecl)
+{
+  struct decl_chain * warned;
+
+  for (warned = warned_decls;
+       warned != NULL;
+       warned = warned->next)
+    if (warned->fndecl == fndecl)
+      return true;
+
+  return false;
+}
+
 /* Perform any actions necessary before starting to compile FNDECL.
    For the RX we use this to make sure that we have the correct
    set of register masks selected.  If FNDECL is NULL then we are
@@ -1288,6 +1323,24 @@ 
       target_reinit ();
     }
 
+  if (current_is_fast_interrupt && rx_warn_multiple_fast_interrupts)
+    {
+      /* We do not warn about the first fast interrupt routine that
+	 we see.  Instead we just push it onto the stack.  */
+      if (warned_decls == NULL)
+	add_warned_decl (fndecl);
+
+      /* Otherwise if this fast interrupt is one for which we have
+	 not already issued a warning, generate one and then push
+	 it onto the stack as well.  */
+      else if (! already_warned (fndecl))
+	{
+	  warning (0, "multiple fast interrupt routines seen: %qE and %qE",
+		   fndecl, warned_decls->fndecl);
+	  add_warned_decl (fndecl);
+	}
+    }
+
   rx_previous_fndecl = fndecl;
 }
 
Index: gcc/config/rx/rx.opt
===================================================================
--- gcc/config/rx/rx.opt	(revision 192034)
+++ gcc/config/rx/rx.opt	(working copy)
@@ -118,3 +118,9 @@ 
 mpid
 Target Mask(PID)
 Enables Position-Independent-Data (PID) mode.
+
+;---------------------------------------------------
+
+mwarn-multiple-fast-interrupts
+Target Report Var(rx_warn_multiple_fast_interrupts) Init(1) Warning
+Warn when multiple, different, fast interrupt handlers are in the compilation unit.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi	(revision 192034)
+++ gcc/doc/invoke.texi	(working copy)
@@ -859,6 +859,7 @@ 
 -mmax-constant-size=@gol
 -mint-register=@gol
 -mpid@gol
+-mno-warn-multiple-fast-interrupts@gol
 -msave-acc-in-interrupts}
 
 @emph{S/390 and zSeries Options}
@@ -17875,6 +17876,15 @@ 
 By default this feature is not enabled.  The default can be restored
 via the @option{-mno-pid} command-line option.
 
+@item -mno-warn-multiple-fast-interrupts
+@itemx -mwarn-multiple-fast-interrupts
+@opindex mno-warn-multiple-fast-interrupts
+@opindex mwarn-multiple-fast-interrupts
+Prevents GCC from issuing a warning message if it finds more than one
+fast interrupt handler when it is compiling a file.  The default is to
+issue a warning for each extra fast interrupt handler found, as the RX
+only supports one such interrupt.
+
 @end table
 
 @emph{Note:} The generic GCC command-line option @option{-ffixed-@var{reg}}

Index: htdocs/gcc-4.8/changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.8/changes.html,v
retrieving revision 1.32
diff -u -3 -p -r1.32 changes.html
--- htdocs/gcc-4.8/changes.html	2 Oct 2012 18:45:36 -0000	1.32
+++ htdocs/gcc-4.8/changes.html	3 Oct 2012 16:09:58 -0000
@@ -239,6 +239,14 @@  by this change.</p>
     operating systems manage the VRSAVE register directly.</li>
   </ul>
 
+<h3 id="rx">RX</h3>
+  <ul>
+    <li>This target will now issue a warning message whenever multiple fast
+    interrupt handlers are found in the same cpmpilation unit.  This feature can
+    be turned off by the new <code>-mno-warn-multiple-fast-interrupts</code>
+    command line option.
+  </ul>
+
 <h3 id="sh">SH</h3>
   <ul>
     <li>The default alignment settings have been reduced to be less aggressive.