Index: lnt/trunk/lnt/tests/test_suite.py
===================================================================
--- lnt/trunk/lnt/tests/test_suite.py
+++ lnt/trunk/lnt/tests/test_suite.py
@@ -202,7 +202,7 @@
                          type=str, metavar="PATH",
                          help="Path to the LLVM test-suite externals")
         group.add_option("", "--cmake-define", dest="cmake_defines",
-                         action="append",
+                         action="append", default=[],
                          help=("Defines to pass to cmake. These do not require the "
                                "-D prefix and can be given multiple times. e.g.: "
                                "--cmake-define A=B => -DA=B"))
@@ -578,6 +578,14 @@
             note('          (In %s)' % kwargs['cwd'])
         return subprocess.check_call(*args, **kwargs)
 
+    def _check_output(self, *args, **kwargs):
+        note('Execute: %s' % ' '.join(args[0]))
+        if 'cwd' in kwargs:
+            note('          (In %s)' % kwargs['cwd'])
+        output = subprocess.check_output(*args, **kwargs)
+        sys.stdout.write(output)
+        return output
+
     def _clean(self, path):
         make_cmd = self.opts.make
 
@@ -621,14 +629,28 @@
             if 'TEST_SUITE_RUN_TYPE' not in defs:
                 defs['TEST_SUITE_RUN_TYPE'] = 'ref'
 
-        if self.opts.cmake_defines:
-            for item in self.opts.cmake_defines:
-                k, v = item.split('=', 1)
-                defs[k] = v
-        for item in extra_cmake_defs:
+        for item in self.opts.cmake_defines + extra_cmake_defs:
             k, v = item.split('=', 1)
+            # make sure the overriding of the settings above also works
+            # when the cmake-define-defined variable has a datatype
+            # specified.
+            key_no_datatype = k.split(':', 1)[0]
+            if key_no_datatype in defs:
+                del defs[key_no_datatype]
             defs[k] = v
 
+        # We use 'cmake -LAH -N' later to find out the value of the
+        # CMAKE_C_COMPILER and CMAKE_CXX_COMPILER variables.
+        # 'cmake -LAH -N' will only return variables in the cache that have
+        # a cmake type set. Therefore, explicitly set a 'FILEPATH' type on
+        # these variables here, if they were untyped so far.
+        if 'CMAKE_C_COMPILER' in defs:
+            defs['CMAKE_C_COMPILER:FILEPATH'] = defs['CMAKE_C_COMPILER']
+            del defs['CMAKE_C_COMPILER']
+        if 'CMAKE_CXX_COMPILER' in defs:
+            defs['CMAKE_CXX_COMPILER:FILEPATH'] = defs['CMAKE_CXX_COMPILER']
+            del defs['CMAKE_CXX_COMPILER']
+
         lines = ['Configuring with {']
         for k, v in sorted(defs.items()):
             lines.append("  %s: '%s'" % (k, v))
@@ -737,14 +759,42 @@
         name = raw_name.rsplit('.test', 1)[0]
         return not os.path.exists(os.path.join(path, name))
 
-    def _get_target_flags(self):
-        assert self.configured is True
-        return shlex.split(self.opts.cppflags + self.opts.cflags)
+    def _get_target_flags(self, cmake_vars):
+        build_type = cmake_vars["build_type"]
+        cflags = cmake_vars["c_flags"]
+        if build_type != "":
+            cflags = \
+                " ".join(cflags.split(" ") +
+                         cmake_vars["c_flags_"+build_type.lower()].split(" "))
+        return shlex.split(cflags)
 
     def _get_cc_info(self):
         assert self.configured is True
-        return lnt.testing.util.compilers.get_cc_info(self.opts.cc,
-                                                      self._get_target_flags())
+        cmake_lah_output = self._check_output(
+            [self.opts.cmake] + ['-LAH', '-N'] + [self._base_path])
+        pattern2var = [
+            (re.compile("^%s:[^=]*=(.*)$" % cmakevar), var)
+            for cmakevar, var in (
+                ("CMAKE_C_COMPILER", "cc"),
+                ("CMAKE_BUILD_TYPE", "build_type"),
+                ("CMAKE_CXX_FLAGS", "cxx_flags"),
+                ("CMAKE_CXX_FLAGS_DEBUG", "cxx_flags_debug"),
+                ("CMAKE_CXX_FLAGS_MINSIZEREL", "cxx_flags_minsizerel"),
+                ("CMAKE_CXX_FLAGS_RELEASE", "cxx_flags_release"),
+                ("CMAKE_CXX_FLAGS_RELWITHDEBINFO", "cxx_flags_relwithdebinfo"),
+                ("CMAKE_C_FLAGS", "c_flags"),
+                ("CMAKE_C_FLAGS_DEBUG", "c_flags_debug"),
+                ("CMAKE_C_FLAGS_MINSIZEREL", "c_flags_minsizerel"),
+                ("CMAKE_C_FLAGS_RELEASE", "c_flags_release"),
+                ("CMAKE_C_FLAGS_RELWITHDEBINFO", "c_flags_relwithdebinfo"),)]
+        cmake_vars = {}
+        for line in cmake_lah_output.split("\n"):
+            for pattern, varname in pattern2var:
+                m = re.match(pattern, line)
+                if m:
+                    cmake_vars[varname] = m.group(1)
+        return lnt.testing.util.compilers.get_cc_info(
+            cmake_vars["cc"], self._get_target_flags(cmake_vars))
 
     def _parse_lit_output(self, path, data, only_test=False):
         LIT_METRIC_TO_LNT = {
Index: lnt/trunk/tests/SharedInputs/FakeCompilers/clang++-r154332
===================================================================
--- lnt/trunk/tests/SharedInputs/FakeCompilers/clang++-r154332
+++ lnt/trunk/tests/SharedInputs/FakeCompilers/clang++-r154332
@@ -0,0 +1 @@
+link fakecompiler.py
\ No newline at end of file
Index: lnt/trunk/tests/SharedInputs/FakeCompilers/clang-r154332
===================================================================
--- lnt/trunk/tests/SharedInputs/FakeCompilers/clang-r154332
+++ lnt/trunk/tests/SharedInputs/FakeCompilers/clang-r154332
@@ -0,0 +1 @@
+link fakecompiler.py
\ No newline at end of file
Index: lnt/trunk/tests/SharedInputs/FakeCompilers/fakecompiler.py
===================================================================
--- lnt/trunk/tests/SharedInputs/FakeCompilers/fakecompiler.py
+++ lnt/trunk/tests/SharedInputs/FakeCompilers/fakecompiler.py
@@ -80,6 +80,20 @@
  "%s" "-cc1" "-E" ... more boring stuff here ...""" % (
             g_program,)
 
+class Clang_r154332(LLVMCompiler):
+    compiler_name = "clang-r154332"
+
+    def print_verbose_info(self):
+        print >>sys.stderr, """\
+clang version 3.1 (trunk 154332) (llvm/trunk 154329)
+Target: x86_64-apple-darwin11.3.0
+Thread model: posix
+InstalledDir: /home/foo/bin
+"""
+        print >>sys.stderr, """\
+ "%s" "-cc1" "-E" ... more boring stuff here ...""" % (
+            g_program,)
+
 # Clang build from a git repository.
 class Clang_git(LLVMCompiler):
     compiler_name = "clang-git"
Index: lnt/trunk/tests/runtest/Inputs/test-suite-cmake/fake-cmake
===================================================================
--- lnt/trunk/tests/runtest/Inputs/test-suite-cmake/fake-cmake
+++ lnt/trunk/tests/runtest/Inputs/test-suite-cmake/fake-cmake
@@ -1,17 +1,56 @@
 #!/bin/bash
 
-# If we passed a cache, just drop it and look like cmake.
-if [[ $1 == "-C" ]]; then
+CMAKE_SRC_DIR="notfound"
+DUMP_VARS=false
+CMAKE_C_COMPILER=""
+CMAKE_CXX_COMPILER=""
+
+while test $# -gt 0
+do
+  if [[ $1 == "-C" ]]; then
+    # If we passed a cache, just drop it and look like cmake.
     echo "Cmake Cache $2"
     shift
-    shift    
-fi    
-if [[ ! -f $1/CMakeLists.txt ]]; then
-  exit 1
+    shift
+  elif [[ $1 == -D* ]]; then
+    # handle -D arguments to cmake.
+    if [[ $1 == -DCMAKE_C_COMPILER:* ]]; then CMAKE_C_COMPILER=${1#*=}; fi
+    if [[ $1 == -DCMAKE_CXX_COMPILER:* ]]; then CMAKE_CXX_COMPILER=${1#*=}; fi
+    shift
+  elif [[ $1 == -LAH && $2 == -N ]]; then
+    DUMP_VARS=true
+    shift
+    shift
+  elif [[ ! -f $1/CMakeLists.txt && ! -f $1/CMakeCache.txt ]]; then
+    # arguments not starting with -D or -C are assumed to point to the cmake
+    # src or build dir
+    exit 1
+  else
+    CMAKE_SRC_DIR=$1
+    # if CMakeCache.txt exists, read in value for compiler
+    if [[ -f $1/CMakeCache.txt ]]; then
+        CMAKE_C_COMPILER=`grep CMAKE_C_COMPILER:FILEPATH= $1/CMakeCache.txt | cut -f2 -d'='`
+        CMAKE_CXX_COMPILER=`grep CMAKE_CXX_COMPILER:FILEPATH= $1/CMakeCache.txt | cut -f2 -d'='`
+    fi
+    shift
+  fi
+done
+
+if [[ $DUMP_VARS == "true" ]]
+then
+  echo CMAKE_C_COMPILER:FILEPATH=$CMAKE_C_COMPILER
+  echo CMAKE_CXX_COMPILER:FILEPATH=$CMAKE_CXX_COMPILER
+  echo CMAKE_BUILD_TYPE:STRING=RelWithDebInfo
+  echo CMAKE_C_FLAGS:STRING=-O0
+  echo CMAKE_CXX_FLAGS:STRING=
+  echo CMAKE_C_FLAGS_RELWITHDEBINFO:STRING=-O2 -g
+  echo CMAKE_CXX_FLAGS_RELWITHDEBINFO:STRING=-O2 -g
 else
-  cp $1/fake-test $1/fake-results.json $1/fake-results-profile.json .
+  cp $CMAKE_SRC_DIR/fake-test $CMAKE_SRC_DIR/fake-results.json $CMAKE_SRC_DIR/fake-results-profile.json .
   echo "Dummy" > CMakeCache.txt
+  echo CMAKE_C_COMPILER:FILEPATH=$CMAKE_C_COMPILER >> CMakeCache.txt
+  echo CMAKE_CXX_COMPILER:FILEPATH=$CMAKE_CXX_COMPILER >> CMakeCache.txt
   mkdir subtest
-  cp $1/fake-test $1/fake-results.json subtest
-  exit 0
+  cp $CMAKE_SRC_DIR/fake-test $CMAKE_SRC_DIR/fake-results.json subtest
 fi
+exit 0
Index: lnt/trunk/tests/runtest/test_suite.py
===================================================================
--- lnt/trunk/tests/runtest/test_suite.py
+++ lnt/trunk/tests/runtest/test_suite.py
@@ -380,6 +380,22 @@
 # RUN: FileCheck  --check-prefix CHECK-MISSING-CC < %t.err %s
 # CHECK-MISSING-CC: error: --cc is required
 
+# Check on conflicting -cc and -cmake-define=CMAKE_C_COMPILER
+# options, the right compiler gets stored in the json report
+# RUN: lnt runtest test-suite \
+# RUN:     --sandbox %t.SANDBOX \
+# RUN:     --no-timestamp \
+# RUN:     --test-suite %S/Inputs/test-suite-cmake \
+# RUN:     --cmake-define=CMAKE_C_COMPILER:STRING=%{shared_inputs}/FakeCompilers/clang-r154332 \
+# RUN:     --cc %{shared_inputs}/FakeCompilers/clang-r154331 \
+# RUN:     --use-cmake %S/Inputs/test-suite-cmake/fake-cmake \
+# RUN:     --use-make %S/Inputs/test-suite-cmake/fake-make \
+# RUN:     --use-lit %S/Inputs/test-suite-cmake/fake-lit \
+# RUN:     > %t.log 2> %t.err || true
+# RUN: FileCheck --check-prefix CHECK-CC-CONFL-CMAKEDEFINE < %t.SANDBOX/build/report.json %s
+# CHECK-CC-CONFL-CMAKEDEFINE: "run_order": "154332"
+
+
 # Check running with PGO
 # RUN: lnt runtest test-suite \
 # RUN:     --sandbox %t.SANDBOX \