[PATCH 02/13] Allow the front-end to create calls with a static chain

[Richard Henderson <rth at redhat dot com>]

And, at the same time, allow indirect calls to have a static chain.
We'll always eliminate the static chain if we can prove it's unused.
---
 gcc/calls.c       | 14 ++++++++------
 gcc/gimple-fold.c | 21 +++++++++++++++++++++
 gcc/gimplify.c    | 17 ++++++++++++++++-
 gcc/tree-cfg.c    | 22 +++++++---------------
 4 files changed, 52 insertions(+), 22 deletions(-)

diff --git a/gcc/calls.c b/gcc/calls.c
index 9c19f38..68abe46 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -173,7 +173,7 @@ static void restore_fixed_argument_area (rtx, rtx, int, int);
    CALL_INSN_FUNCTION_USAGE information.  */
 
 rtx
-prepare_call_address (tree fndecl, rtx funexp, rtx static_chain_value,
+prepare_call_address (tree fndecl_or_type, rtx funexp, rtx static_chain_value,
 		      rtx *call_fusage, int reg_parm_seen, int sibcallp)
 {
   /* Make a valid memory address and copy constants through pseudo-regs,
@@ -193,12 +193,13 @@ prepare_call_address (tree fndecl, rtx funexp, rtx static_chain_value,
 #endif
     }
 
-  if (static_chain_value != 0)
+  if (static_chain_value != 0
+      && (TREE_CODE (fndecl_or_type) != FUNCTION_DECL
+	  || DECL_STATIC_CHAIN (fndecl_or_type)))
     {
       rtx chain;
 
-      gcc_assert (fndecl);
-      chain = targetm.calls.static_chain (fndecl, false);
+      chain = targetm.calls.static_chain (fndecl_or_type, false);
       static_chain_value = convert_memory_address (Pmode, static_chain_value);
 
       emit_move_insn (chain, static_chain_value);
@@ -3106,8 +3107,9 @@ expand_call (tree exp, rtx target, int ignore)
 	}
 
       after_args = get_last_insn ();
-      funexp = prepare_call_address (fndecl, funexp, static_chain_value,
-				     &call_fusage, reg_parm_seen, pass == 0);
+      funexp = prepare_call_address (fndecl ? fndecl : fntype, funexp,
+				     static_chain_value, &call_fusage,
+				     reg_parm_seen, pass == 0);
 
       load_register_parameters (args, num_actuals, &call_fusage, flags,
 				pass == 0, &sibcall_failure);
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 8ac2211..d5baa72 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -2636,6 +2636,27 @@ gimple_fold_call (gimple_stmt_iterator *gsi, bool inplace)
 	}
     }
 
+  /* Check for indirect calls that became direct calls, and then
+     no longer require a static chain.  */
+  if (gimple_call_chain (stmt))
+    {
+      tree fn = gimple_call_fndecl (stmt);
+      if (fn && !DECL_STATIC_CHAIN (fn))
+	{
+	  gimple_call_set_chain (stmt, NULL);
+	  changed = true;
+	}
+      else
+	{
+	  tree tmp = maybe_fold_reference (gimple_call_chain (stmt), false);
+	  if (tmp)
+	    {
+	      gimple_call_set_chain (stmt, tmp);
+	      changed = true;
+	    }
+	}
+    }
+
   if (inplace)
     return changed;
 
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 6ee85f2..a08e217 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -2414,7 +2414,7 @@ gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool want_value)
 	}
     }
 
-  /* Finally, gimplify the function arguments.  */
+  /* Gimplify the function arguments.  */
   if (nargs > 0)
     {
       for (i = (PUSH_ARGS_REVERSED ? nargs - 1 : 0);
@@ -2436,6 +2436,21 @@ gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool want_value)
         }
     }
 
+  /* Gimplify the static chain.  */
+  if (CALL_EXPR_STATIC_CHAIN (*expr_p))
+    {
+      if (fndecl && !DECL_STATIC_CHAIN (fndecl))
+	CALL_EXPR_STATIC_CHAIN (*expr_p) = NULL;
+      else
+	{
+	  enum gimplify_status t;
+	  t = gimplify_arg (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p,
+			    EXPR_LOCATION (*expr_p));
+	  if (t == GS_ERROR)
+	    ret = GS_ERROR;
+	}
+    }
+
   /* Verify the function result.  */
   if (want_value && fndecl
       && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fnptrtype))))
diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index e88842a..5fd56c1 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -3297,22 +3297,14 @@ verify_gimple_call (gimple stmt)
       return true;
     }
 
-  /* If there is a static chain argument, this should not be an indirect
-     call, and the decl should have DECL_STATIC_CHAIN set.  */
-  if (gimple_call_chain (stmt))
+  /* If there is a static chain argument, the call should either be
+     indirect, or the decl should have DECL_STATIC_CHAIN set.  */
+  if (gimple_call_chain (stmt)
+      && fndecl
+      && !DECL_STATIC_CHAIN (fndecl))
     {
-      if (!gimple_call_fndecl (stmt))
-	{
-	  error ("static chain in indirect gimple call");
-	  return true;
-	}
-      fn = TREE_OPERAND (fn, 0);
-
-      if (!DECL_STATIC_CHAIN (fn))
-	{
-	  error ("static chain with function that doesn%'t use one");
-	  return true;
-	}
+      error ("static chain with function that doesn%'t use one");
+      return true;
     }
 
   /* ???  The C frontend passes unpromoted arguments in case it
-- 
1.9.3