Re: [PATCH] [testsuite] Pass -lpthread in libs

Simon Marchi
2017-11-17T16:54:57Z

On 2017-11-17 10:22 AM, Yao Qi wrote:
> "libs" is the right flag to pass a library to a linker, instead of
> additional_flags. Without this patch, the test case can't be complied
> by clang.
>
> gdb compile failed, clang: warning: -lpthread: 'linker' input unused
>
> gdb/testsuite:
>
> 2017-11-17 Yao Qi <yao.qi@linaro.org>
>
> * gdb.base/info-os.exp: Pass -lpthread in libs.
> * gdb.multi/multi-attach.exp: Likewise.
> ---
> gdb/testsuite/gdb.base/info-os.exp | 2 +-
> gdb/testsuite/gdb.multi/multi-attach.exp | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/testsuite/gdb.base/info-os.exp b/gdb/testsuite/gdb.base/info-os.exp
> index 574da26..b3109e1 100644
> --- a/gdb/testsuite/gdb.base/info-os.exp
> +++ b/gdb/testsuite/gdb.base/info-os.exp
> @@ -28,7 +28,7 @@ if [gdb_skip_xml_test] then {
> }
>
> # Compile test program.
> -if { [prepare_for_testing "failed to prepare" $testfile $srcfile {debug additional_flags=-lpthread}] } {
> +if { [prepare_for_testing "failed to prepare" $testfile $srcfile {debug libs=-lpthread}] } {
> fail "cannot compile test program"
> return -1
> }
> diff --git a/gdb/testsuite/gdb.multi/multi-attach.exp b/gdb/testsuite/gdb.multi/multi-attach.exp
> index 9397f85..52acc91 100644
> --- a/gdb/testsuite/gdb.multi/multi-attach.exp
> +++ b/gdb/testsuite/gdb.multi/multi-attach.exp
> @@ -23,7 +23,7 @@ if {![can_spawn_for_attach]} {
> return 0
> }
>
> -if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug additional_flags=-lpthread}]} {
> +if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug libs=-lpthread}]} {
> return -1
> }
>
>

Hi Yao,

I am seeing:

gdb compile failed, .../info-os.c:51:1: warning: control reaches end of non-void function [-Wreturn-type]

with clang-6.0. Once I fix it, the test passes for me.

Instead of passing -lpthread directly, it would probably be better to pass the
"pthreads" option, like this:

diff --git a/gdb/testsuite/gdb.base/info-os.exp b/gdb/testsuite/gdb.base/info-os.exp
index 574da26..3267eec 100644
--- a/gdb/testsuite/gdb.base/info-os.exp
+++ b/gdb/testsuite/gdb.base/info-os.exp
@@ -28,7 +28,7 @@ if [gdb_skip_xml_test] then {
}

# Compile test program.
-if { [prepare_for_testing "failed to prepare" $testfile $srcfile {debug additional_flags=-lpthread}] } {
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] } {
fail "cannot compile test program"
return -1
}

build_executable_from_specs eventually converts that into a call to gdb_compile_pthreads,
which then chooses the right linker flag based on the platform. So it's a bit more portable.

Simon