re PR fortran/90329 (Incompatibility between gfortran and C lapack calls)

	PR fortran/90329
	* tree-core.h (struct tree_decl_common): Document
	decl_nonshareable_flag for PARM_DECLs.
	* tree.h (DECL_HIDDEN_STRING_LENGTH): Define.
	* calls.c (expand_call): Don't try tail call if caller
	has any DECL_HIDDEN_STRING_LENGTH PARM_DECLs that are or might be
	passed on the stack and callee needs to pass any arguments on the
	stack.
	* tree-streamer-in.c (unpack_ts_decl_common_value_fields): Use
	else if instead of series of mutually exclusive ifs.  Handle
	DECL_HIDDEN_STRING_LENGTH for PARM_DECLs.
	* tree-streamer-out.c (pack_ts_decl_common_value_fields): Likewise.

	* trans-decl.c (create_function_arglist): Set
	DECL_HIDDEN_STRING_LENGTH on hidden string length PARM_DECLs if
	len is constant.

From-SVN: r271285

1 files changed, 22 insertions, 0 deletions

diff --git a/gcc/calls.c b/gcc/calls.c
index 6b22e7a..c8a4268 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -3628,6 +3628,28 @@ expand_call (tree exp, rtx target, int ignore)
       || dbg_cnt (tail_call) == false)
     try_tail_call = 0;
 
+  /* Workaround buggy C/C++ wrappers around Fortran routines with
+     character(len=constant) arguments if the hidden string length arguments
+     are passed on the stack; if the callers forget to pass those arguments,
+     attempting to tail call in such routines leads to stack corruption.
+     Avoid tail calls in functions where at least one such hidden string
+     length argument is passed (partially or fully) on the stack in the
+     caller and the callee needs to pass any arguments on the stack.
+     See PR90329.  */
+  if (try_tail_call && maybe_ne (args_size.constant, 0))
+    for (tree arg = DECL_ARGUMENTS (current_function_decl);
+	 arg; arg = DECL_CHAIN (arg))
+      if (DECL_HIDDEN_STRING_LENGTH (arg) && DECL_INCOMING_RTL (arg))
+	{
+	  subrtx_iterator::array_type array;
+	  FOR_EACH_SUBRTX (iter, array, DECL_INCOMING_RTL (arg), NONCONST)
+	    if (MEM_P (*iter))
+	      {
+		try_tail_call = 0;
+		break;
+	      }
+	}
+
   /* If the user has marked the function as requiring tail-call
      optimization, attempt it.  */
   if (must_tail_call)