[binutils-gdb] testsuite: Disable ccache

[Jan Kratochvil <jkratoch at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=49b4de64242d4ae035e0e2197837278e33c187fc

commit 49b4de64242d4ae035e0e2197837278e33c187fc
Author: Jan Kratochvil <jan.kratochvil@redhat.com>
Date:   Thu Sep 15 14:04:20 2016 +0200

    testsuite: Disable ccache
    
    There were always various problems with compatibility with ccache:
    	https://bugzilla.redhat.com/show_bug.cgi?id=488863
    	https://bugzilla.redhat.com/show_bug.cgi?id=759592
    	https://sourceware.org/ml/gdb-patches/2009-02/msg00397.html
    
    IMO in a summary ccache finds more a benefit of faster compilation despite the
    debug info is no longer exactly the same (as without ccache).
    
    Although for example in this case ccache helped to find a real GDB bug:
    	https://sourceware.org/ml/gdb-patches/2015-01/msg00497.html
    
    For the GDB testcases ccache has (IMO) no real performance advantage and it
    just brings heisenbugs - false FAILs - from time to time:
    
    Breakpoint 1, main () at gdb/testsuite/gdb.base/vdso-warning.c:21^M
    	21        return 0;^M
    	(gdb) PASS: gdb.base/vdso-warning.exp: run: startup
    	->
    	Breakpoint 1, main () at gdb/testsuite/gdb.base/hbreak-unmapped.c:21^M
    	21        return 0;^M
    	(gdb) FAIL: gdb.base/vdso-warning.exp: run: startup
    
    So I find most safe and easy to just disable ccache for all testsuites.
    
    gdb/testsuite/ChangeLog
    2016-09-15  Jan Kratochvil  <jan.kratochvil@redhat.com>
    
    	* lib/future.exp: Set CCACHE_DISABLE, clear CCACHE_NODISABLE.

Diff:
---
 gdb/testsuite/ChangeLog      | 4 ++++
 gdb/testsuite/lib/future.exp | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index c63ea72..cf49f25 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2016-09-15  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* lib/future.exp: Set CCACHE_DISABLE, clear CCACHE_NODISABLE.
+
 2016-09-11  Sergio Durigan Junior  <sergiodj@redhat.com>
 	    Jan Kratochvil  <jan.kratochvil@redhat.com>
 
diff --git a/gdb/testsuite/lib/future.exp b/gdb/testsuite/lib/future.exp
index 2ecff2e..e7c9d9a 100644
--- a/gdb/testsuite/lib/future.exp
+++ b/gdb/testsuite/lib/future.exp
@@ -666,3 +666,8 @@ if {[info procs lreverse] == ""} {
 	return $retval
     }
 }
+
+# Various ccache versions provide incorrect debug info such as ignoring
+# different current directory, breaking GDB testsuite.
+set env(CCACHE_DISABLE) 1
+unset -nocomplain env(CCACHE_NODISABLE)