diff --git a/cross-project-tests/CMakeLists.txt b/cross-project-tests/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/cross-project-tests/CMakeLists.txt
@@ -0,0 +1,40 @@
+set(CROSS_PROJECT_TEST_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+set(CROSS_PROJECT_TEST_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
+set(LLVM_TOOLS_DIR "${LLVM_TOOLS_BINARY_DIR}/%(build_config)s")
+
+set(CROSS_TEST_DEPS FileCheck)
+list(APPEND CROSS_TEST_DEPS
+  llvm-readelf
+)
+
+if ("lld" IN_LIST LLVM_ENABLE_PROJECTS)
+  set(LLD_BINARY_DIR "${CROSS_PROJECT_TEST_BINARY_DIR}/../lld")
+  list(APPEND CROSS_TEST_DEPS lld)
+endif()
+
+if ("clang" IN_LIST LLVM_ENABLE_PROJECTS)
+  set(CLANG_BINARY_DIR "${CROSS_PROJECT_TEST_BINARY_DIR}/../clang")
+  list(APPEND CROSS_TEST_DEPS clang)
+endif()
+
+configure_lit_site_cfg(
+  ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
+  ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg.py
+  MAIN_CONFIG
+  ${CMAKE_CURRENT_SOURCE_DIR}/lit.cfg.py
+  )
+
+
+add_lit_testsuite(check-cross-project "Running cross-project test suite"
+  ${CMAKE_CURRENT_BINARY_DIR}
+  DEPENDS ${CROSS_TEST_DEPS}
+  )
+
+add_custom_target(cross-project-test-depends DEPENDS ${CROSS_TEST_DEPS})
+set_target_properties(cross-project-test-depends PROPERTIES FOLDER "Tests")
+
+add_lit_testsuites(LLVM ${CMAKE_CURRENT_SOURCE_DIR}
+  DEPENDS ${CROSS_TEST_DEPS}
+  )
+
+set_target_properties(check-cross-project PROPERTIES FOLDER "Tests")
diff --git a/cross-project-tests/lit.cfg.py b/cross-project-tests/lit.cfg.py
new file mode 100644
--- /dev/null
+++ b/cross-project-tests/lit.cfg.py
@@ -0,0 +1,29 @@
+# -*- Python -*-
+
+import os
+
+import lit.formats
+
+from lit.llvm import llvm_config
+
+config.name = 'cross-project'
+config.test_format = lit.formats.ShTest(not llvm_config.use_lit_shell)
+
+config.suffixes = ['.c']
+config.excludes = ['Inputs']
+
+config.test_source_root = os.path.dirname(__file__)
+config.test_exec_root = config.cross_projects_obj_root
+
+llvm_config.use_default_substitutions()
+
+if len(config.lld_obj_root) > 0:
+    config.available_features.add('lld')
+    llvm_config.use_lld()
+
+if len(config.clang_obj_root) > 0:
+    config.available_features.add('clang')
+    llvm_config.use_clang()
+
+tool_patterns = ["llvm-readelf"]
+llvm_config.add_tool_substitutions(tool_patterns)
diff --git a/cross-project-tests/lit.site.cfg.py.in b/cross-project-tests/lit.site.cfg.py.in
new file mode 100644
--- /dev/null
+++ b/cross-project-tests/lit.site.cfg.py.in
@@ -0,0 +1,24 @@
+@LIT_SITE_CFG_IN_HEADER@
+
+import lit.util
+
+config.cross_projects_obj_root = "@CROSS_PROJECT_TEST_BINARY_DIR@"
+config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
+config.lld_obj_root = "@LLD_BINARY_DIR@"
+config.clang_obj_root = "@CLANG_BINARY_DIR@"
+config.target_triple = "@TARGET_TRIPLE@"
+config.host_triple = "@LLVM_HOST_TRIPLE@"
+
+# Support substitution of the tools and libs dirs with user parameters. This is
+# used when we can't determine the tool dir at configuration time.
+try:
+    config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
+except KeyError as e:
+    key, = e.args
+    lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
+
+import lit.llvm
+lit.llvm.initialize(lit_config, config)
+
+# Let the main config do the real work.
+lit_config.load_config(config, "@CROSS_PROJECT_TEST_DIR@/lit.cfg.py")
diff --git a/cross-project-tests/lld-clang.c b/cross-project-tests/lld-clang.c
new file mode 100644
--- /dev/null
+++ b/cross-project-tests/lld-clang.c
@@ -0,0 +1,10 @@
+// REQUIRES: lld, clang
+
+//// Demo test.
+
+// RUN: %clang -c %s -o %t.o
+// RUN: ld.lld %t.o -o %t.elf
+// RUN: llvm-readelf %t.elf -s | FileCheck %s
+// CHECK: _start
+
+void _start(){}
\ No newline at end of file
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -58,7 +58,7 @@
 # LLVM_EXTERNAL_${project}_SOURCE_DIR using LLVM_ALL_PROJECTS
 # This allows an easy way of setting up a build directory for llvm and another
 # one for llvm+clang+... using the same sources.
-set(LLVM_ALL_PROJECTS "clang;clang-tools-extra;compiler-rt;debuginfo-tests;libc;libclc;libcxx;libcxxabi;libunwind;lld;lldb;mlir;openmp;parallel-libs;polly;pstl")
+set(LLVM_ALL_PROJECTS "clang;clang-tools-extra;compiler-rt;cross-project-tests;debuginfo-tests;libc;libclc;libcxx;libcxxabi;libunwind;lld;lldb;mlir;openmp;parallel-libs;polly;pstl")
 # The flang project is not yet part of "all" projects (see C++ requirements)
 set(LLVM_EXTRA_PROJECTS "flang")
 # List of all known projects in the mono repo
diff --git a/llvm/tools/CMakeLists.txt b/llvm/tools/CMakeLists.txt
--- a/llvm/tools/CMakeLists.txt
+++ b/llvm/tools/CMakeLists.txt
@@ -51,4 +51,8 @@
   add_llvm_external_project(${p})
 endforeach(p)
 
+# The cross-project tests are intended to support all previous projects, so
+# should be last.
+add_llvm_external_project(cross-project-tests)
+
 set(LLVM_COMMON_DEPENDS ${LLVM_COMMON_DEPENDS} PARENT_SCOPE)