libstdc++: testsuite: skip fs space tests on dummy implementations

The do_space function is defined in ways that are useful, or that fail
immediately, depending on various macros.  When it fails immediately,
the filesystem space.cc tests fail noisily, but the fail is entirely
expected.

Define NO_SPACE in testsuite_fs.h, according to the macros that select
implementations of do_space, and use it to skip tests that are
expected to fail, through a new dg-require.


for  libstdc++-v3/ChangeLog

	* testsuite/util/testsuite_fs.h (NO_SPACE): Define if
	appropriate.
	* testsuite/lib/libstdc++.exp (check_v3_target_fs_space): New.
	* testsuite/lib/dg-options.exp (dg-require-target-fs-space):
	New.
	* testsuite/27_io/filesystem/operations/space.cc: Require
	target-fs-space.
	* testsuite/experimental/filesystem/operations/space.cc:
	Likewise.

5 files changed, 24 insertions, 0 deletions

diff --git a/libstdc++-v3/testsuite/27_io/filesystem/operations/space.cc b/libstdc++-v3/testsuite/27_io/filesystem/operations/space.cc
index 05997ca..daa1ce4 100644
--- a/libstdc++-v3/testsuite/27_io/filesystem/operations/space.cc
+++ b/libstdc++-v3/testsuite/27_io/filesystem/operations/space.cc
@@ -17,6 +17,7 @@
 
 // { dg-do run { target c++17 } }
 // { dg-require-filesystem-ts "" }
+// { dg-require-target-fs-space "" }
 
 // 30.10.14.3 Permissions [fs.op.space]
 
diff --git a/libstdc++-v3/testsuite/experimental/filesystem/operations/space.cc b/libstdc++-v3/testsuite/experimental/filesystem/operations/space.cc
index 10ee0f0..c3745a2 100644
--- a/libstdc++-v3/testsuite/experimental/filesystem/operations/space.cc
+++ b/libstdc++-v3/testsuite/experimental/filesystem/operations/space.cc
@@ -18,6 +18,7 @@
 // { dg-options "-DUSE_FILESYSTEM_TS -lstdc++fs" }
 // { dg-do run { target c++11 } }
 // { dg-require-filesystem-ts "" }
+// { dg-require-target-fs-space "" }
 
 // 30.10.14.3 Permissions [fs.op.space]
 
diff --git a/libstdc++-v3/testsuite/lib/dg-options.exp b/libstdc++-v3/testsuite/lib/dg-options.exp
index e624a69..81bb8f4 100644
--- a/libstdc++-v3/testsuite/lib/dg-options.exp
+++ b/libstdc++-v3/testsuite/lib/dg-options.exp
@@ -250,6 +250,15 @@ proc dg-require-target-fs-symlinks { args } {
     return
 }
 
+proc dg-require-target-fs-space { args } {
+    if { ![ check_v3_target_fs_space ] } {
+	upvar dg-do-what dg-do-what
+	set dg-do-what [list [lindex ${dg-do-what} 0] "N" "P"]
+	return
+    }
+    return
+}
+
 proc add_options_for_no_pch { flags } {
     # This forces any generated and possibly included PCH to be invalid.
     return "-D__GLIBCXX__=99999999"
diff --git a/libstdc++-v3/testsuite/lib/libstdc++.exp b/libstdc++-v3/testsuite/lib/libstdc++.exp
index 03f47e8..4305ec6 100644
--- a/libstdc++-v3/testsuite/lib/libstdc++.exp
+++ b/libstdc++-v3/testsuite/lib/libstdc++.exp
@@ -1278,6 +1278,14 @@ proc check_v3_target_fs_symlinks { } {
     return [v3_check_preprocessor_condition fs_symlinks $cond $inc]
 }
 
+# Return 1 if the libstdc++ filesystem implementation of space is not an
+# always-failing dummy.
+proc check_v3_target_fs_space { } {
+    set inc "#include <testsuite_fs.h>"
+    set cond "!defined NO_SPACE"
+    return [v3_check_preprocessor_condition fs_space $cond $inc]
+}
+
 # Return 1 if the "cxx11" ABI is in use using the current flags, 0 otherwise.
 # Any flags provided by RUNTESTFLAGS or a target board will be used here.
 # Flags added in the test by dg-options or dg-add-options will not be used.
diff --git a/libstdc++-v3/testsuite/util/testsuite_fs.h b/libstdc++-v3/testsuite/util/testsuite_fs.h
index 03af7ae..e9fb4ff 100644
--- a/libstdc++-v3/testsuite/util/testsuite_fs.h
+++ b/libstdc++-v3/testsuite/util/testsuite_fs.h
@@ -46,6 +46,11 @@ namespace test_fs = std::experimental::filesystem;
 #define NO_SYMLINKS
 #endif
 
+#if !defined (_GLIBCXX_HAVE_SYS_STATVFS_H) \
+  && !defined (_GLIBCXX_FILESYSTEM_IS_WINDOWS)
+#define NO_SPACE
+#endif
+
 namespace __gnu_test
 {
 #define PATH_CHK(p1, p2, fn) \