From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16250 invoked by alias); 24 Apr 2003 01:05:43 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 16243 invoked from network); 24 Apr 2003 01:05:42 -0000 Received: from unknown (HELO mx1.redhat.com) (66.187.233.31) by sources.redhat.com with SMTP; 24 Apr 2003 01:05:42 -0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.11.6/8.11.6) with ESMTP id h3O15gD26772 for ; Wed, 23 Apr 2003 21:05:42 -0400 Received: from pobox.corp.redhat.com (pobox.corp.redhat.com [172.16.52.156]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id h3O15gq22757 for ; Wed, 23 Apr 2003 21:05:42 -0400 Received: from localhost.localdomain (vpn50-7.rdu.redhat.com [172.16.50.7]) by pobox.corp.redhat.com (8.11.6/8.11.6) with ESMTP id h3O15fk08887 for ; Wed, 23 Apr 2003 21:05:41 -0400 Received: (from kev@localhost) by localhost.localdomain (8.11.6/8.11.6) id h3O15a018158 for gdb-patches@sources.redhat.com; Wed, 23 Apr 2003 18:05:36 -0700 Date: Thu, 24 Apr 2003 03:46:00 -0000 From: Kevin Buettner Message-Id: <1030424010535.ZM18157@localhost.localdomain> To: gdb-patches@sources.redhat.com Subject: [RFA] dwarf2expr.c: Prepare for eventual DW_OP_piece support MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-SW-Source: 2003-04/txt/msg00460.txt.bz2 The patch below prepares execute_stack_op() for eventual DW_OP_piece support. The relatively obvious part of the patch is the revision of the tests which force DW_OP_reg operations to be used alone. These tests have been revised to permit a DW_OP_piece operator to follow a DW_OP_reg* operator. The not so obvious part concerns the initialization of ctx->in_reg. When a DW_OP_piece case is eventually added, it will need to know whether the thing on the stack is a register or some other kind of location expression. At the moment, the only indication we have of what this thing is is being cleared each time through the loop. Moving it out of the loop will allow a DW_OP_piece case to use this information for determining how to proceed. Okay? * dwarf2expr.c (execute_stack_op): Move ``ctx->in_reg'' initialization out of loop. Allow DW_OP_reg0 ... DW_OP_reg31 and DW_OP_regx to be used in conjuction with DW_OP_piece. Revise error message accordingly. Index: dwarf2expr.c =================================================================== RCS file: /cvs/src/src/gdb/dwarf2expr.c,v retrieving revision 1.6 diff -u -p -r1.6 dwarf2expr.c --- dwarf2expr.c 13 Apr 2003 15:53:44 -0000 1.6 +++ dwarf2expr.c 24 Apr 2003 00:36:43 -0000 @@ -228,6 +227,8 @@ static void execute_stack_op (struct dwarf_expr_context *ctx, unsigned char *op_ptr, unsigned char *op_end) { + ctx->in_reg = 0; + while (op_ptr < op_end) { enum dwarf_location_atom op = *op_ptr++; @@ -236,8 +237,6 @@ execute_stack_op (struct dwarf_expr_cont LONGEST offset; int bytes_read; - ctx->in_reg = 0; - switch (op) { case DW_OP_lit0: @@ -355,10 +354,9 @@ execute_stack_op (struct dwarf_expr_cont case DW_OP_reg29: case DW_OP_reg30: case DW_OP_reg31: - /* NOTE: in the presence of DW_OP_piece this check is incorrect. */ - if (op_ptr != op_end) + if (op_ptr != op_end && *op_ptr != DW_OP_piece) error ("DWARF-2 expression error: DW_OP_reg operations must be " - "used alone."); + "used either alone or in conjuction with DW_OP_piece."); result = op - DW_OP_reg0; ctx->in_reg = 1; @@ -367,9 +365,9 @@ execute_stack_op (struct dwarf_expr_cont case DW_OP_regx: op_ptr = read_uleb128 (op_ptr, op_end, ®); - if (op_ptr != op_end) + if (op_ptr != op_end && *op_ptr != DW_OP_piece) error ("DWARF-2 expression error: DW_OP_reg operations must be " - "used alone."); + "used either alone or in conjuction with DW_OP_piece."); result = reg; ctx->in_reg = 1;