Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-cpp/TestDataFormatterCpp.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-cpp/TestDataFormatterCpp.py
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-cpp/TestDataFormatterCpp.py
@@ -26,6 +26,8 @@
     @expectedFailureAll(
         oslist=["windows"],
         bugnumber="llvm.org/pr24462: Data formatters have problems on Windows")
+    @skipIf(debug_info="gmodules",
+            bugnumber="https://bugs.llvm.org/show_bug.cgi?id=36048")
     def test_with_run_command(self):
         """Test that that file and class static variables display correctly."""
         self.build()
Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-globals/TestDataFormatterGlobals.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-globals/TestDataFormatterGlobals.py
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-globals/TestDataFormatterGlobals.py
@@ -9,6 +9,7 @@
 import time
 import lldb
 from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
 import lldbsuite.test.lldbutil as lldbutil
 
 
@@ -22,6 +23,8 @@
         # Find the line number to break at.
         self.line = line_number('main.cpp', '// Set break point at this line.')
 
+    @skipIf(debug_info="gmodules",
+            bugnumber="https://bugs.llvm.org/show_bug.cgi?id=36048")
     def test_with_run_command(self):
         """Test that that file and class static variables display correctly."""
         self.build()
Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/list/TestDataFormatterLibcxxList.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/list/TestDataFormatterLibcxxList.py
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/list/TestDataFormatterLibcxxList.py
@@ -31,6 +31,8 @@
                                  '// Set fourth break point at this line.')
 
     @add_test_categories(["libc++"])
+    @skipIf(debug_info="gmodules",
+            bugnumber="https://bugs.llvm.org/show_bug.cgi?id=36048")
     def test_with_run_command(self):
         """Test that that file and class static variables display correctly."""
         self.build()
Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/vector/TestDataFormatterLibcxxVector.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/vector/TestDataFormatterLibcxxVector.py
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/vector/TestDataFormatterLibcxxVector.py
@@ -18,6 +18,8 @@
     mydir = TestBase.compute_mydir(__file__)
 
     @add_test_categories(["libc++"])
+    @skipIf(debug_info="gmodules",
+            bugnumber="https://bugs.llvm.org/show_bug.cgi?id=36048")
     def test_with_run_command(self):
         """Test that that file and class static variables display correctly."""
         self.build()
Index: lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-auto-import/Makefile
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-auto-import/Makefile
+++ lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-auto-import/Makefile
@@ -1,6 +1,6 @@
 LEVEL = ../../../make
 OBJC_SOURCES := main.m
 
-CFLAGS += -fmodules -gmodules -g
+CFLAGS += $(MANDATORY_MODULE_BUILD_CFLAGS)
 
 include $(LEVEL)/Makefile.rules
Index: lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-auto-import/TestModulesAutoImport.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-auto-import/TestModulesAutoImport.py
+++ lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-auto-import/TestModulesAutoImport.py
@@ -26,7 +26,7 @@
         self.line = line_number('main.m', '// Set breakpoint 0 here.')
 
     @skipUnlessDarwin
-    @skipIf(macos_version=["<", "10.12"])
+    @skipIf(macos_version=["<", "10.12"], debug_info=no_match(["gmodules"]))
     def test_expr(self):
         self.build()
         exe = self.getBuildArtifact("a.out")
Index: lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-incomplete/Makefile
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-incomplete/Makefile
+++ lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-incomplete/Makefile
@@ -4,5 +4,5 @@
 
 include $(LEVEL)/Makefile.rules
 
-CFLAGS += -fmodules -I$(PWD)
+CFLAGS += $(MANDATORY_MODULE_BUILD_CFLAGS) -I$(PWD)
 LDFLAGS += -framework Foundation
Index: lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-incomplete/TestIncompleteModules.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-incomplete/TestIncompleteModules.py
+++ lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-incomplete/TestIncompleteModules.py
@@ -24,7 +24,7 @@
 
     @skipUnlessDarwin
     @unittest2.expectedFailure("rdar://20416388")
-    @skipIf(macos_version=["<", "10.12"])
+    @skipIf(macos_version=["<", "10.12"], debug_info=no_match(["gmodules"]))
     def test_expr(self):
         self.build()
         exe = self.getBuildArtifact("a.out")
Index: lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-inline-functions/Makefile
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-inline-functions/Makefile
+++ lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-inline-functions/Makefile
@@ -6,4 +6,4 @@
 
 include $(LEVEL)/Makefile.rules
 
-CFLAGS += -fmodules -I$(PWD)
+CFLAGS += $(MANDATORY_MODULE_BUILD_CFLAGS) -I$(PWD)
Index: lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-inline-functions/TestModulesInlineFunctions.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-inline-functions/TestModulesInlineFunctions.py
+++ lldb/trunk/packages/Python/lldbsuite/test/lang/objc/modules-inline-functions/TestModulesInlineFunctions.py
@@ -27,7 +27,7 @@
         self.line = line_number('main.m', '// Set breakpoint here.')
 
     @skipUnlessDarwin
-    @skipIf(macos_version=["<", "10.12"])
+    @skipIf(macos_version=["<", "10.12"], debug_info=no_match(["gmodules"]))
     def test_expr(self):
         self.build()
         exe = self.getBuildArtifact("a.out")
Index: lldb/trunk/packages/Python/lldbsuite/test/make/Makefile.rules
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/make/Makefile.rules
+++ lldb/trunk/packages/Python/lldbsuite/test/make/Makefile.rules
@@ -237,13 +237,15 @@
 	CFLAGS += -gsplit-dwarf
 endif
 
+CLANG_MODULE_CACHE_DIR := module-cache
+
+MANDATORY_MODULE_BUILD_CFLAGS := -fmodules -gmodules -fmodules-cache-path=$(CLANG_MODULE_CACHE_DIR)
+
 ifeq "$(MAKE_GMODULES)" "YES"
-	CFLAGS += -fmodules -gmodules
+	CFLAGS += $(MANDATORY_MODULE_BUILD_CFLAGS)
 endif
 
-CXXFLAGS += -std=c++11
-# FIXME: C++ modules aren't supported on all platforms.
-CXXFLAGS += $(subst -fmodules,, $(CFLAGS))
+CXXFLAGS += -std=c++11 $(CFLAGS)
 LD = $(CC)
 LDFLAGS ?= $(CFLAGS)
 LDFLAGS += $(LD_EXTRAS) $(ARCH_LDFLAGS)
@@ -636,7 +638,7 @@
 dsym:	$(DSYM)
 all:	$(EXE) $(DSYM)
 clean::
-	$(RM) $(OBJECTS) $(PREREQS) $(PREREQS:.d=.d.tmp) $(DWOS) $(ARCHIVE_NAME) $(ARCHIVE_OBJECTS)
+	$(RM) -rf $(OBJECTS) $(PREREQS) $(PREREQS:.d=.d.tmp) $(DWOS) $(ARCHIVE_NAME) $(ARCHIVE_OBJECTS) $(CLANG_MODULE_CACHE_DIR)
 ifneq "$(DYLIB_NAME)" ""
 	$(RM) -r $(DYLIB_FILENAME).dSYM
 	$(RM) $(DYLIB_OBJECTS) $(DYLIB_PREREQS) $(DYLIB_PREREQS:.d=.d.tmp) $(DYLIB_DWOS) $(DYLIB_FILENAME) $(DYLIB_FILENAME).debug