Index: lldb/trunk/test/dotest.py
===================================================================
--- lldb/trunk/test/dotest.py
+++ lldb/trunk/test/dotest.py
@@ -125,20 +125,9 @@
 # By default, benchmarks tests are not run.
 just_do_benchmarks_test = False
 
-# By default, both dsym and dwarf tests are performed.
-# Use @dsym_test or @dwarf_test decorators, defined in lldbtest.py, to mark a test
-# as a dsym or dwarf test.  Use '-N dsym' or '-N dwarf' to exclude dsym or dwarf
-# tests from running.
-dont_do_dsym_test = "linux" in sys.platform or "freebsd" in sys.platform
+dont_do_dsym_test = False
 dont_do_dwarf_test = False
 
-# Don't do debugserver tests on everything except OS X.
-# Something for Windows here?
-dont_do_debugserver_test = "linux" in sys.platform or "freebsd" in sys.platform
-
-# Don't do lldb-server (llgs) tests on anything except Linux.
-dont_do_llgs_test = not ("linux" in sys.platform)
-
 # The blacklist is optional (-b blacklistFile) and allows a central place to skip
 # testclass's and/or testclass.testmethod's.
 blacklist = None
@@ -1358,6 +1347,22 @@
 else:
     lldb.remote_platform = None
     lldb.remote_platform_working_dir = None
+
+target_platform = lldb.DBG.GetSelectedPlatform().GetTriple().split('-')[2]
+
+# By default, both dsym and dwarf tests are performed.
+# Use @dsym_test or @dwarf_test decorators, defined in lldbtest.py, to mark a test
+# as a dsym or dwarf test.  Use '-N dsym' or '-N dwarf' to exclude dsym or dwarf
+# tests from running.
+dont_do_dsym_test = dont_do_dsym_test or "linux" in target_platform or "freebsd" in target_platform
+
+# Don't do debugserver tests on everything except OS X.
+# Something for Windows here?
+dont_do_debugserver_test = "linux" in target_platform or "freebsd" in target_platform
+
+# Don't do lldb-server (llgs) tests on anything except Linux.
+dont_do_llgs_test = not ("linux" in target_platform)
+
 # Put the blacklist in the lldb namespace, to be used by lldb.TestBase.
 lldb.blacklist = blacklist
 
Index: lldb/trunk/test/lldbtest.py
===================================================================
--- lldb/trunk/test/lldbtest.py
+++ lldb/trunk/test/lldbtest.py
@@ -584,22 +584,24 @@
 def expectedFailurex86_64(bugnumber=None):
     if bugnumber: return expectedFailureArch('x86_64', bugnumber)
 
-def expectedFailureOS(os, bugnumber=None, compilers=None):
+def expectedFailureOS(oslist, bugnumber=None, compilers=None):
     def fn(self):
-        return os in sys.platform and self.expectedCompiler(compilers)
+        return (lldb.DBG.GetSelectedPlatform().GetTriple().split('-')[2] in oslist and
+                self.expectedCompiler(compilers))
     if bugnumber: return expectedFailure(fn, bugnumber)
 
 def expectedFailureDarwin(bugnumber=None, compilers=None):
-    if bugnumber: return expectedFailureOS('darwin', bugnumber, compilers)
+    # For legacy reasons, we support both "darwin" and "macosx" as OS X triples.
+    if bugnumber: return expectedFailureOS(['darwin', 'macosx'], bugnumber, compilers)
 
 def expectedFailureFreeBSD(bugnumber=None, compilers=None):
-    if bugnumber: return expectedFailureOS('freebsd', bugnumber, compilers)
+    if bugnumber: return expectedFailureOS(['freebsd'], bugnumber, compilers)
 
 def expectedFailureLinux(bugnumber=None, compilers=None):
-    if bugnumber: return expectedFailureOS('linux', bugnumber, compilers)
+    if bugnumber: return expectedFailureOS(['linux'], bugnumber, compilers)
 
 def expectedFailureWindows(bugnumber=None, compilers=None):
-    if bugnumber: return expectedFailureOS('win32', bugnumber, compilers)
+    if bugnumber: return expectedFailureOS(['windows'], bugnumber, compilers)
 
 def expectedFailureLLGS(bugnumber=None, compilers=None):
     def fn(self):
@@ -646,7 +648,7 @@
     def wrapper(*args, **kwargs):
         from unittest2 import case
         self = args[0]
-        platform = sys.platform
+        platform = lldb.DBG.GetSelectedPlatform().GetTriple().split('-')[2]
         if "freebsd" in platform:
             self.skipTest("skip on FreeBSD")
         else:
@@ -661,7 +663,7 @@
     def wrapper(*args, **kwargs):
         from unittest2 import case
         self = args[0]
-        platform = sys.platform
+        platform = lldb.DBG.GetSelectedPlatform().GetTriple().split('-')[2]
         if "linux" in platform:
             self.skipTest("skip on linux")
         else:
@@ -695,8 +697,8 @@
     def wrapper(*args, **kwargs):
         from unittest2 import case
         self = args[0]
-        platform = sys.platform
-        if "win32" in platform:
+        platform = lldb.DBG.GetSelectedPlatform().GetTriple().split('-')[2]
+        if "windows" in platform:
             self.skipTest("skip on Windows")
         else:
             func(*args, **kwargs)
@@ -710,8 +712,8 @@
     def wrapper(*args, **kwargs):
         from unittest2 import case
         self = args[0]
-        platform = sys.platform
-        if "darwin" in platform:
+        platform = lldb.DBG.GetSelectedPlatform().GetTriple().split('-')[2]
+        if "darwin" in platform or "macosx" in platform:
             self.skipTest("skip on darwin")
         else:
             func(*args, **kwargs)