[Ping] [PATCH] Testsuite: Ensure stack protection is off for GCC

[Alan Hayward <Alan.Hayward@arm.com>]

Ping.

Note there is a fix patch for GCC under review here:
https://gcc.gnu.org/ml/gcc-patches/2019-01/msg00543.html
Once it is in an upstream GCC release, I can expand the GDB change
to only disable stack protection on older GCCs.


Alan.


> On 7 Jan 2019, at 16:57, Alan Hayward <Alan.Hayward@arm.com> wrote:
> 
> Forgot to mention: this fixes ~60 tests when running make check on Ubuntu.
> 
> 
>> On 7 Jan 2019, at 16:37, Alan Hayward <Alan.Hayward@arm.com> wrote:
>> 
>> Using -fstack-protector-strong will cause GDB to break on the wrong line
>> when placing a breakpoint on a function.  This is caused by due to
>> inadequate dwarf line numbering, and is being tracked by the GCC bug
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88432
>> 
>> GCC (and Clang) provided by Debian/Ubuntu default to Stack Protector
>> being enabled.
>> 
>> So, ensure that when running the GDB testsuite, stack protector is always
>> turned off for GCC (option has existed since GCC 4.1.0).
>> 
>> Also, ensure that this does not cause infinite recursion due to
>> test_compiler_info having to compile a file itself.
>> 
>> Restore change in ovldbreak.exp which worked around the issue.
>> 
>> [Side note - this fix would be improved by checking for Ubuntu/Debian,
>> but I don't see any existing checks for that in the testsuite]
>> 
>> 2019-01-07  Alan Hayward  <alan.hayward@arm.com>
>> 
>> 	* gdb.cp/ovldbreak.exp: Only allow a single break line.
>> 	* lib/gdb.exp (get_compiler_info): Use getting_compiler_info option.
>> 	(gdb_compile): Remove stack protector for GCC and prevent recursion.
>> ---
>> gdb/testsuite/gdb.cp/ovldbreak.exp |  2 +-
>> gdb/testsuite/lib/gdb.exp          | 17 +++++++++++++++--
>> 2 files changed, 16 insertions(+), 3 deletions(-)
>> 
>> diff --git a/gdb/testsuite/gdb.cp/ovldbreak.exp b/gdb/testsuite/gdb.cp/ovldbreak.exp
>> index 494f2a12e9..3ffd04209a 100644
>> --- a/gdb/testsuite/gdb.cp/ovldbreak.exp
>> +++ b/gdb/testsuite/gdb.cp/ovldbreak.exp
>> @@ -209,7 +209,7 @@ for {set idx 0} {$idx < [llength $overloads]} {incr idx} {
>> 
>> # Verify the breakpoints.
>> set bptable "Num\[\t \]+Type\[\t \]+Disp Enb Address\[\t \]+What.*\[\r\n]+"
>> -append bptable "\[0-9\]+\[\t \]+breakpoint\[\t \]+keep\[\t \]y\[\t \]+$hex\[\t \]+in main(\\((|void)\\))? at.*$srcfile:4\[89\]\[\r\n\]+"
>> +append bptable "\[0-9\]+\[\t \]+breakpoint\[\t \]+keep\[\t \]y\[\t \]+$hex\[\t \]+in main(\\((|void)\\))? at.*$srcfile:49\[\r\n\]+"
>> append bptable "\[\t \]+breakpoint already hit 1 time\[\r\n\]+."
>> foreach ovld $overloads {
>>    append bptable [format "\[0-9\]+\[\t \]+breakpoint\[\t \]+keep y\[\t \]+$hex\[\t \]+in foo::overload1arg\\(%s\\) at.*$srcfile:%d\[\r\n\]+" $ovld \
>> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
>> index ed9f89d5a7..7443638a72 100644
>> --- a/gdb/testsuite/lib/gdb.exp
>> +++ b/gdb/testsuite/lib/gdb.exp
>> @@ -3276,12 +3276,12 @@ proc get_compiler_info {{arg ""}} {
>> 	# We have to use -E and -o together, despite the comments
>> 	# above, because of how DejaGnu handles remote host testing.
>> 	set ppout "$outdir/compiler.i"
>> -	gdb_compile "${ifile}" "$ppout" preprocess [list "$arg" quiet]
>> +	gdb_compile "${ifile}" "$ppout" preprocess [list "$arg" quiet getting_compiler_info]
>> 	set file [open $ppout r]
>> 	set cppout [read $file]
>> 	close $file
>>    } else {
>> -	set cppout [ gdb_compile "${ifile}" "" preprocess [list "$arg" quiet] ]
>> +	set cppout [ gdb_compile "${ifile}" "" preprocess [list "$arg" quiet getting_compiler_info] ]
>>    }
>>    eval log_file $saved_log
>> 
>> @@ -3519,6 +3519,7 @@ proc gdb_compile {source dest type options} {
>>    }
>>    set shlib_found 0
>>    set shlib_load 0
>> +    set getting_compiler_info 0
>>    foreach opt $options {
>>        if {[regexp {^shlib=(.*)} $opt dummy_var shlib_name]
>> 	    && $type == "executable"} {
>> @@ -3549,11 +3550,23 @@ proc gdb_compile {source dest type options} {
>>            }
>> 	} elseif { $opt == "shlib_load" && $type == "executable" } {
>> 	    set shlib_load 1
>> +	} elseif { $opt == "getting_compiler_info" } {
>> +	    # If this is set, calling test_compiler_info will cause recursion.
>> +	    set getting_compiler_info 1
>>        } else {
>>            lappend new_options $opt
>>        }
>>    }
>> 
>> +    # Ensure stack protector is disabled for GCC, as this will causes problems
>> +    # with DWARF line numbering.
>> +    # See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88432
>> +    # This option defaults to on for Debian/Ubuntu.
>> +    if { $getting_compiler_info == 0 && [test_compiler_info "gcc-*"] } {
>> +        # Put it at the front to not override any user-provided value
>> +        lappend new_options "early_flags=-fno-stack-protector"
>> +    }
>> +
>>    # Because we link with libraries using their basename, we may need
>>    # (depending on the platform) to set a special rpath value, to allow
>>    # the executable to find the libraries it depends on.
>> -- 
>> 2.17.2 (Apple Git-113)
>> 
>