[ld, testsuite] Restrict dl1*main and dl6*main tests on platforms which have libdl support

[Jiong Wang <jiong dot wang at foss dot arm dot com>]

Some tests in ld-elf/share.exp require dlopen support.  One platforms where
there are not such support I got the following compilation errors:

  ld/testsuite/ld-elf/dl1main.c:2:10: fatal error: dlfcn.h: No such file or directory
   #include <dlfcn.h>
          ^~~~~~~~~

  ERROR: /work/BLD/8.3/src/binutils-gdb/ld/testsuite/ld-elf/dl6amain.c: compilation failed
  UNRESOLVED: Run dl6a6 with --dynamic-list-cpp-new -Bsymbolic-functions and dlopen on libdl6a.so
  
  
This patch restricts those tests on platform where libdl is available.  The
availability check is done through compiling a sample test file which includes
"dlfcn.h".

This patch cut off 13 unresolved testcases on my arm-none-eabi environment and no regression.
Also no regression on arm-none-linux-gnu/x86-64 native check-ld.


OK for master?

Thanks.

ld/
2017-02-01  Jiong Wang  <jiong.wang@arm.com>

        * testsuite/lib/ld-lib.exp (check_libdl_available): New function.
        * testsuite/ld-elf/shared.exp (run_tests): Split tests which require
        dlopen support into "dlopen_run_tests".  These tests include dl1*main
        and dl6*main.
        (dlopen_run_tests): New and only run it when check_libdl_available
        returns true.

diff --git a/ld/testsuite/ld-elf/shared.exp b/ld/testsuite/ld-elf/shared.exp
index eea9453..e9d465d 100644
--- a/ld/testsuite/ld-elf/shared.exp
+++ b/ld/testsuite/ld-elf/shared.exp
@@ -373,12 +373,6 @@ set run_tests [list \
     [list "Run hidden libbar.so with versioned libfoo.so" \
      "-Wl,--no-as-needed tmpdir/libbarhfoov.so tmpdir/libfoov.so" "" \
      {main.c} "hidden" "hidden.out" ] \
-    [list "Run dl1a with --dynamic-list=dl1.list and dlopen on libdl1.so" \
-     "-Wl,--no-as-needed,--dynamic-list=dl1.list $extralibs" "" \
-     {dl1main.c} "dl1a" "dl1.out" ] \
-    [list "Run dl1b with --dynamic-list-data and dlopen on libdl1.so" \
-     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
-     {dl1main.c} "dl1b" "dl1.out" ] \
     [list "Run with libdl2a.so" \
      "-Wl,--no-as-needed tmpdir/libdl2a.so" "" \
      {dl2main.c} "dl2a" "dl2a.out" ] \
@@ -406,39 +400,6 @@ set run_tests [list \
     [list "Run with libdl4f.so" \
      "-Wl,--no-as-needed tmpdir/libdl4f.so" "" \
      {dl4main.c} "dl4f" "dl4a.out" ] \
-    [list "Run dl6a1 with --dynamic-list-data and dlopen on libdl6a.so" \
-     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
-     {dl6amain.c} "dl6a1" "dl6a.out" ] \
-    [list "Run dl6a2 with -Bsymbolic-functions and dlopen on libdl6a.so" \
-     "-Wl,--no-as-needed,-Bsymbolic-functions $extralibs" "" \
-     {dl6amain.c} "dl6a2" "dl6b.out" ] \
-    [list "Run dl6a3 with -Bsymbolic and dlopen on libdl6a.so" \
-     "-Wl,--no-as-needed,-Bsymbolic $extralibs" "" \
-     {dl6amain.c} "dl6a3" "dl6b.out" ] \
-    [list "Run dl6a4 with -Bsymbolic --dynamic-list-data and dlopen on libdl6a.so" \
-     "-Wl,--no-as-needed,-Bsymbolic,--dynamic-list-data $extralibs" "" \
-     {dl6amain.c} "dl6a4" "dl6a.out" ] \
-    [list "Run dl6a5 with -Bsymbolic-functions --dynamic-list-cpp-new and dlopen on libdl6a.so" \
-     "-Wl,--no-as-needed,-Bsymbolic-functions,--dynamic-list-cpp-new $extralibs" "" \
-     {dl6amain.c} "dl6a5" "dl6b.out" ] \
-    [list "Run dl6a6 with --dynamic-list-cpp-new -Bsymbolic-functions and dlopen on libdl6a.so" \
-     "-Wl,--no-as-needed,--dynamic-list-cpp-new,-Bsymbolic-functions $extralibs" "" \
-     {dl6amain.c} "dl6a6" "dl6b.out" ] \
-    [list "Run dl6a7 with --dynamic-list-data -Bsymbolic and dlopen on libdl6a.so" \
-     "-Wl,--no-as-needed,--dynamic-list-data,-Bsymbolic $extralibs" "" \
-     {dl6amain.c} "dl6a7" "dl6a.out" ] \
-    [list "Run dl6b1 with --dynamic-list-data and dlopen on libdl6b.so" \
-     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
-     {dl6bmain.c} "dl6b1" "dl6a.out" ] \
-    [list "Run dl6b2 with dlopen on libdl6b.so" \
-     "-Wl,--no-as-needed $extralibs" "" \
-     {dl6bmain.c} "dl6b2" "dl6b.out" ] \
-    [list "Run dl6c1 with --dynamic-list-data and dlopen on libdl6c.so" \
-     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
-     {dl6cmain.c} "dl6c1" "dl6b.out" ] \
-    [list "Run dl6d1 with --dynamic-list-data and dlopen on libdl6d.so" \
-     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
-     {dl6dmain.c} "dl6d1" "dl6b.out" ] \
     [list "Run with libdata1.so" \
      "-Wl,--no-as-needed tmpdir/libdata1.so" "" \
      {dynbss1.c} "dynbss1" "pass.out" ] \
@@ -486,6 +447,54 @@ set run_tests [list \
 # NetBSD ELF systems do not currently support the .*_array sections.
 run_ld_link_exec_tests $run_tests "*-*-netbsdelf*"
 
+# These tests require dlopen support.
+set dlopen_run_tests [list \
+    [list "Run dl1a with --dynamic-list=dl1.list and dlopen on libdl1.so" \
+     "-Wl,--no-as-needed,--dynamic-list=dl1.list $extralibs" "" \
+     {dl1main.c} "dl1a" "dl1.out" ] \
+    [list "Run dl1b with --dynamic-list-data and dlopen on libdl1.so" \
+     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
+     {dl1main.c} "dl1b" "dl1.out" ] \
+    [list "Run dl6a1 with --dynamic-list-data and dlopen on libdl6a.so" \
+     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
+     {dl6amain.c} "dl6a1" "dl6a.out" ] \
+    [list "Run dl6a2 with -Bsymbolic-functions and dlopen on libdl6a.so" \
+     "-Wl,--no-as-needed,-Bsymbolic-functions $extralibs" "" \
+     {dl6amain.c} "dl6a2" "dl6b.out" ] \
+    [list "Run dl6a3 with -Bsymbolic and dlopen on libdl6a.so" \
+     "-Wl,--no-as-needed,-Bsymbolic $extralibs" "" \
+     {dl6amain.c} "dl6a3" "dl6b.out" ] \
+    [list "Run dl6a4 with -Bsymbolic --dynamic-list-data and dlopen on libdl6a.so" \
+     "-Wl,--no-as-needed,-Bsymbolic,--dynamic-list-data $extralibs" "" \
+     {dl6amain.c} "dl6a4" "dl6a.out" ] \
+    [list "Run dl6a5 with -Bsymbolic-functions --dynamic-list-cpp-new and dlopen on libdl6a.so" \
+     "-Wl,--no-as-needed,-Bsymbolic-functions,--dynamic-list-cpp-new $extralibs" "" \
+     {dl6amain.c} "dl6a5" "dl6b.out" ] \
+    [list "Run dl6a6 with --dynamic-list-cpp-new -Bsymbolic-functions and dlopen on libdl6a.so" \
+     "-Wl,--no-as-needed,--dynamic-list-cpp-new,-Bsymbolic-functions $extralibs" "" \
+     {dl6amain.c} "dl6a6" "dl6b.out" ] \
+    [list "Run dl6a7 with --dynamic-list-data -Bsymbolic and dlopen on libdl6a.so" \
+     "-Wl,--no-as-needed,--dynamic-list-data,-Bsymbolic $extralibs" "" \
+     {dl6amain.c} "dl6a7" "dl6a.out" ] \
+    [list "Run dl6b1 with --dynamic-list-data and dlopen on libdl6b.so" \
+     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
+     {dl6bmain.c} "dl6b1" "dl6a.out" ] \
+    [list "Run dl6b2 with dlopen on libdl6b.so" \
+     "-Wl,--no-as-needed $extralibs" "" \
+     {dl6bmain.c} "dl6b2" "dl6b.out" ] \
+    [list "Run dl6c1 with --dynamic-list-data and dlopen on libdl6c.so" \
+     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
+     {dl6cmain.c} "dl6c1" "dl6b.out" ] \
+    [list "Run dl6d1 with --dynamic-list-data and dlopen on libdl6d.so" \
+     "-Wl,--no-as-needed,--dynamic-list-data $extralibs" "" \
+     {dl6dmain.c} "dl6d1" "dl6b.out" ] \
+]
+
+# Only run them when libdl is available.
+if [check_libdl_available] {
+  run_ld_link_exec_tests $dlopen_run_tests
+}
+
 # Check --no-add-needed and --no-copy-dt-needed-entries
 set testname "--no-add-needed"
 set exec_output [run_host_cmd "$CC" "tmpdir/libneeded1c.o -Wl,--no-add-needed,-rpath-link=tmpdir -Ltmpdir -lneeded1a"]
diff --git a/ld/testsuite/lib/ld-lib.exp b/ld/testsuite/lib/ld-lib.exp
index a44358e..61626ec 100644
--- a/ld/testsuite/lib/ld-lib.exp
+++ b/ld/testsuite/lib/ld-lib.exp
@@ -2120,3 +2120,38 @@ proc istarget { target } {
     }
     return [istarget_ld $target]
 }
+
+# Return true if libdl is supported.
+
+proc check_libdl_available { } {
+    global libdl_available_saved
+    global CC
+
+    if {![info exists libdl_available_saved]} {
+        if { [which $CC] == 0 } {
+	    set libdl_available_saved 0
+	    return 0
+	}
+
+	set basename "tmpdir/dl_avail_test[pid]"
+	set src ${basename}.c
+	set output ${basename}.out
+	set f [open $src "w"]
+	# Sample test file.
+	puts $f "#include <dlfcn.h>"
+	puts $f "int main (void)"
+	puts $f "{"
+	puts $f "  dlopen (\"dummy.so\", RTLD_NOW);"
+	puts $f "  return 0; "
+	puts $f "}"
+	close $f
+	if [is_remote host] {
+	    set src [remote_download host $src]
+	}
+	set libdl_available_saved [run_host_cmd_yesno "$CC" "$src -o $output -ldl"]
+	remote_file host delete $src
+	remote_file host delete $output
+	file delete $src
+    }
+    return $libdl_available_saved
+}