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Re: Weird behaviour with --target_board="unix{var1,var2}"


On 23/08/16 09:07 +0100, Jonathan Wakely wrote:
On 22/08/16 21:16 +0100, Pedro Alves wrote:
On 08/22/2016 03:40 PM, Jonathan Wakely wrote:

What's going on?!

Have I fundamentally misunderstood something about how RUNTESTFLAGS or
effective-target keywords work?


Here's a wild guess.

In gdb's testsuite, I've seen odd problems like these being caused by some
tcl global getting set on the first run using one board, then then the
second run using the second board finds the variable already set and
skips something.  E.g.:

https://sourceware.org/ml/gdb-patches/2015-04/msg00261.html

I'd look at the code that decides whether to run a test in a particular
mode with the above in mind.  Given that reordering the boards makes
a difference, it kind of sounds like some "last checked mode" or some
such variable is bleeding between runs.

I've tracked it down to this block of code in
/usr/share/dejagnu/dg.exp:

  # Don't do this if we're testing an interpreter.
  # FIXME: why?
  if { ${dg-interpreter-batch-mode} == 0 } {
	# Catch excess errors (new bugs or incomplete testcases).
	if {${dg-excess-errors-flag}} {
	    setup_xfail "*-*-*"
	}
	if {![string match "" $comp_output]} {
	    fail "$name (test for excess errors)"
	    send_log "Excess errors:\n$comp_output\n"
	} else {
	    pass "$name (test for excess errors)"
	}
  }

Adding some logging to the libstdc++-dg-test callback shows that
${dg-interpreter-batch-mode}  == 1 for the tests which don't print
their result.

That's being set by prettyprinters.exp and xmethods.exp (so it's GDB's
fault! ;-) because they want to keep the executables around, to run
GDB on. When we run with multiple boards that variable doesn't get
reset to 0 for the next run of conformance.exp

That also explains why putting RUNTESTFLAGS="conformance.exp..." fixes
it, because the other .exp files aren't used, so batch mode is never
set.

Shouldn't be too hard to fix.

This seems to work. I'll do some more testing and commit later today.



commit 5bdadc8628977b3a462876efd0e7919b1ec8f5a7
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Aug 23 09:09:18 2016 +0100

    Restore dg-interpreter-batch-mode for libstdc++ tests
    
    	* testsuite/libstdc++-prettyprinters/prettyprinters.exp: Restore
    	original value of dg-interpreter-batch-mode.
    	* testsuite/libstdc++-xmethods/xmethods.exp: Likewise.

diff --git a/libstdc++-v3/testsuite/libstdc++-prettyprinters/prettyprinters.exp b/libstdc++-v3/testsuite/libstdc++-prettyprinters/prettyprinters.exp
index 0c62b5e..dcc99fb 100644
--- a/libstdc++-v3/testsuite/libstdc++-prettyprinters/prettyprinters.exp
+++ b/libstdc++-v3/testsuite/libstdc++-prettyprinters/prettyprinters.exp
@@ -44,6 +44,7 @@ if {! [gdb_version_check]} {
 # This can be used to keep the .exe around.  dg-test has an option for
 # this but there is no way to pass it through dg-runtest.
 global dg-interpreter-batch-mode
+set saved-dg-interpreter-batch-mode ${dg-interpreter-batch-mode}
 set dg-interpreter-batch-mode 1
 
 global DEFAULT_CXXFLAGS
@@ -55,4 +56,6 @@ if [info exists guality_gdb_name] {
     unsetenv GUALITY_GDB_NAME
 }
 
+set dg-interpreter-batch-mode ${saved-dg-interpreter-batch-mode}
+
 dg-finish
diff --git a/libstdc++-v3/testsuite/libstdc++-xmethods/xmethods.exp b/libstdc++-v3/testsuite/libstdc++-xmethods/xmethods.exp
index ee9b31a..5809d74 100644
--- a/libstdc++-v3/testsuite/libstdc++-xmethods/xmethods.exp
+++ b/libstdc++-v3/testsuite/libstdc++-xmethods/xmethods.exp
@@ -45,6 +45,7 @@ if {! [gdb_version_check_xmethods]} {
 # This can be used to keep the .exe around.  dg-test has an option for
 # this but there is no way to pass it through dg-runtest.
 global dg-interpreter-batch-mode
+set saved-dg-interpreter-batch-mode ${dg-interpreter-batch-mode}
 set dg-interpreter-batch-mode 1
 
 global DEFAULT_CXXFLAGS
@@ -56,5 +57,7 @@ if [info exists guality_gdb_name] {
     unsetenv GUALITY_GDB_NAME
 }
 
+set dg-interpreter-batch-mode ${saved-dg-interpreter-batch-mode}
+
 dg-finish
 gcc_parallel_test_enable 1

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