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

[Simon Marchi <simon dot marchi at ericsson dot com>]

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