[compiler-rt] [test] Detect glibc-2.27+ and XFAIL appropriate tests

[mgorny]

Summary

XFAIL the tests known to fail with glibc-2.27+. This takes away
the burden of handling known failures from users, and ensures that
we will be verbosely informed when they actually start working again.

Bug report: https://bugs.llvm.org/show_bug.cgi?id=37804

[mgorny]

Ping.

test/lit.common.cfg

try:
     android_api_level = int(android_api_level_str)
   except ValueError:
     lit_config.fatal("Failed to read ro.build.version.sdk (using '%s' as adb): got '%s'" % (adb, android_api_level_str))
   if android_api_level >= 26:
     config.available_features.add('android-26')
   if android_api_level >= 28:
     config.available_features.add('android-28')
 
+if config.host_os == 'Linux':
+  # detect whether we are using glibc, and which version
+  # NB: 'ldd' is just one of the tools commonly installed as part of glibc
+  ldd_ver_cmd = subprocess.Popen(['ldd', '--version'],
+                                 stdout=subprocess.PIPE,
+                                 env={'LANG': 'C'})
+  sout, _ = ldd_ver_cmd.communicate()
+  ver_line = sout.splitlines()[0]
+  if ver_line.startswith(b"ldd "):
+    from distutils.version import LooseVersion
+    ver = LooseVersion(ver_line.split()[-1].decode())
+    # 2.27 introduced some incompatibilities
+    if ver >= LooseVersion("2.27"):
+      config.available_features.add("glibc-2.27")
+
 sancovcc_path = os.path.join(config.llvm_tools_dir, "sancov")
 if os.path.exists(sancovcc_path):
   config.available_features.add("has_sancovcc")
   config.substitutions.append( ("%sancovcc ", sancovcc_path) )
 
 def is_darwin_lto_supported():
   return os.path.exists(os.path.join(config.llvm_shlib_dir, 'libLTO.dylib'))
 

test/lsan/TestCases/Linux/use_tls_dynamic.cc

 // Test that dynamically allocated TLS space is included in the root set.
+
+// This is known to be broken with glibc-2.27+
+// https://bugs.llvm.org/show_bug.cgi?id=37804
+// XFAIL: glibc-2.27
+
 // RUN: LSAN_BASE="report_objects=1:use_stacks=0:use_registers=0:use_ld_allocations=0"
 // RUN: %clangxx %s -DBUILD_DSO -fPIC -shared -o %t-so.so
 // RUN: %clangxx_lsan %s -o %t
 // RUN: %env_lsan_opts=$LSAN_BASE:"use_tls=0" not %run %t 2>&1 | FileCheck %s
 // RUN: %env_lsan_opts=$LSAN_BASE:"use_tls=1" %run %t 2>&1
 // RUN: %env_lsan_opts="" %run %t 2>&1
 // UNSUPPORTED: i386-linux,arm,powerpc
 

test/msan/dtls_test.c

 /* RUN: %clang_msan -g %s -o %t
    RUN: %clang_msan -g %s -DBUILD_SO -fPIC -o %t-so.so -shared
    RUN: %run %t 2>&1
 
    Regression test for a bug in msan/glibc integration,
    see https://sourceware.org/bugzilla/show_bug.cgi?id=16291
    and https://github.com/google/sanitizers/issues/547
 
    XFAIL: FreeBSD
    UNSUPPORTED: powerpc
 
    // Reports use-of-uninitialized-value, not analyzed
    XFAIL: netbsd
+
+   // This is known to be broken with glibc-2.27+
+   // https://bugs.llvm.org/show_bug.cgi?id=37804
+   XFAIL: glibc-2.27
+
 */
 
 #ifndef BUILD_SO
 #include <assert.h>
 #include <dlfcn.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <pthread.h>