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Re: Do not open .gcda/.gcno files in write mode unnecessarily.

From: Nathan Sidwell <nathan at codesourcery dot com>
To: Neil Vachharajani <nvachhar at google dot com>
Cc: gcc-patches at gcc dot gnu dot org, jh at suse dot cz
Date: Tue, 22 Sep 2009 13:26:28 +0100
Subject: Re: Do not open .gcda/.gcno files in write mode unnecessarily.
References: <b3d309910909171123x357dc750m220b9236a3fce827@mail.gmail.com>

Neil Vachharajani wrote:

GCC currently always opens .gcda/.gcno files in write mode.  This
leads to permission denied errors when opening these files if the
files are read-only.  Having read-only .gcda files is useful to ensure
that one does not unintentionally modify profile data (by default, an
instrumented binary will append to .gcda files).  This patch modifies
the behavior of gcov_open to only open the file in write mode if the
MODE argument is >= 0.

Bootstrapped/regtested on x86_64-linux and i686-linux.  Verified that
FDO still works.  Ok for trunk?

2009-09-17 Neil Vachharajani <nvachhar@gmail.com>

* gcov-io.c (gcov_open): Open files read-only when MODE < 0

Can you protect the new read-only code with #if !IN_LIBGCOV, so we don't unnecessarily bloat that? It looks like that's the locking calls as the open call is already in such a #if block.

nathan

--
Nathan Sidwell    ::   http://www.codesourcery.com   ::         CodeSourcery

Follow-Ups:
- Re: Do not open .gcda/.gcno files in write mode unnecessarily.
  - From: Neil Vachharajani

References:
- Do not open .gcda/.gcno files in write mode unnecessarily.
  - From: Neil Vachharajani

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