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Re: Generate tree/rtx for address-of exp?

From: Jim Wilson <wilson at specifixinc dot com>
To: MajorZ <cy_rebate10 at yahoo dot com>
Cc: gcc at gcc dot gnu dot org
Date: Tue, 01 Jun 2004 00:06:27 -0700
Subject: Re: Generate tree/rtx for address-of exp?
References: <20040527035440.90891.qmail@web90008.mail.scd.yahoo.com>

MajorZ wrote:

1. Is there a universal field in tree/rtx for
address-of exp? No matter what exp could be.

No.

2. Is there some function A that could help to
calculate the offset no matter it is structure, array
or mix?

Create an ADDR_EXPR tree, and pass it to expand_expr. That will return RTL corresponding to the address. If you want the address of a struture member, then you need a ADDR_EXPR of a COMPONENT_REF tree. Etc.

3. Can some nice guy could should me the simple
pseudocode for the function A if I have to write it
myself? Or what are the situations I need to think of,
like for array, for strcuture, for arrays of strutures
etc.

Write a simple C testcase, run gdb on cc1, put a breakpoint in expand_expr in the ADDR_EXPR case, and then print out the tree with the pt gdb macro (or use debug_tree directly). -- Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com

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