From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dibyendu Majumdar Subject: Re: sparse-llvm array size computation issue Date: Wed, 29 Mar 2017 21:24:07 +0100 Message-ID: References: <20170328213300.zfa7yecafqvalt5u@macpro.local> <20170328222124.kjtgzrhzsnsxdtq2@macpro.local> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-io0-f177.google.com ([209.85.223.177]:35691 "EHLO mail-io0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754027AbdC2UYJ (ORCPT ); Wed, 29 Mar 2017 16:24:09 -0400 Received: by mail-io0-f177.google.com with SMTP id z13so6627091iof.2 for ; Wed, 29 Mar 2017 13:24:08 -0700 (PDT) In-Reply-To: Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Linus Torvalds Cc: Luc Van Oostenryck , Linux-Sparse On 29 March 2017 at 19:12, Dibyendu Majumdar wrote: > On 29 March 2017 at 17:41, Linus Torvalds wrote: >> On Wed, Mar 29, 2017 at 9:21 AM, Dibyendu Majumdar >> wrote: >>> >>> I am trying out an approach. If a SYM_NODE has a base type of SYM_NODE >>> then which of the nodes should be used as the source for information >>> you mention? >> >> Does that actually happen? It shouldn't. A symbol node contains the C >> name of the symbol, but you should never have a SYM_NODE that points >> to another SYM_NODE, it always points to some actual type (ie ptr, >> whatever). >> >> So the rule should be that the node can have specific information >> about that particular named symbol (so: name, array size, modifiers, >> address space, initializer etc), and then the node->ctype.base_type >> should point to a non-NODE symbol describing the base type. >> > > Okay thank you - that's good to know. It wasn't obvious to me looking > at the code, and I thought I had seen an example where a node > contained another node ... but I cannot find this now, so I may have > been mistaken. > I have implemented a solution in my repository (link below). Basically I split the symbol_type() function into three: get_symnode_type() - when we know the symbol is a SYM_NODE get_symnode_or_basetype() - when we do not know whether a symbol is SYM_NODE or not The original symbol_type() is renamed to type_to_llvmtype() and it: a) takes extra argument that if not NULL is a SYM_NODE b) the original symbol parameter can never be a SYM_NODE. My tests pass. I do not know that I have been as conservative I could - i.e. where the symbol is known to be a SYM_NODE or a base type - it would be good to be as specific as possible. Here is the link to my version: https://github.com/dibyendumajumdar/dmr_c/blob/master/llvm-backend/sparse-llvm.c Thanks and Regards Dibyendu