Implement a CMake based build system for KLEE.

This is based off intial work by @jirislaby in #481. However it
has been substantially modified.

Notably it includes a separate build sytem to build the runtimes which
is inspired by the old build system. The reason for doing this is
because CMake is not well suited for building the runtime:

* CMake is configured to use the host compiler, not the bitcode
  compiler. These are not the same thing.

* Building the runtime using `add_custom_command()` is flawed
  because we can't automatically get transitive depencies (i.e.
  header file dependencies) unless the CMake generator is makefiles.
  (See `IMPLICIT_DEPENDS` of `add_custom_command()` in CMake).

So for now we have a very simple build system for building the runtimes.
In the future we can replace this with something more sophisticated if
we need it.

Support for all features of the old build system are implemented apart
from recording the git revision and showing it in the output of
`klee --help`.

Another notable change is the CMake build system works much better with
LLVM installs which don't ship with testing tools. The build system
will download the sources for `FileCheck` and `not` tools if the
corresponding binaries aren't available and will build them. However
`lit` (availabe via `pip install lit`) and GTest must already be
installed.

Apart from better support for testing a significant advantage of the
new CMake build system compared to the existing "Autoconf/Makefile"
build system is that it is **not** coupled to LLVM's build system
(unlike the existing build system). This means that LLVM's
autoconf/Makefiles don't need to be installed somewhere on the system.

Currently all tests pass.

Support has been implemented in TravisCI and the Dockerfile for
building with CMake.

The existing "Autoconf/Makefile" build system has been left intact
and so both build systems can coexist for a short while. We should
remove the old build system as soon as possible though because it
creates an unnecessary maintance burden.

7 files changed, 148 insertions, 0 deletions

diff --git a/unittests/Assignment/CMakeLists.txt b/unittests/Assignment/CMakeLists.txt
new file mode 100644
index 00000000..e231ee39
--- /dev/null
+++ b/unittests/Assignment/CMakeLists.txt
@@ -0,0 +1,4 @@
+add_klee_unit_test(AssignmentTest
+  AssignmentTest.cpp)
+klee_get_llvm_libs(LLVM_LIBS Support)
+target_link_libraries(AssignmentTest PRIVATE kleaverExpr ${LLVM_LIBS})
diff --git a/unittests/CMakeLists.txt b/unittests/CMakeLists.txt
new file mode 100644
index 00000000..a85c0a74
--- /dev/null
+++ b/unittests/CMakeLists.txt
@@ -0,0 +1,100 @@
+#===------------------------------------------------------------------------===#
+#
+#                     The KLEE Symbolic Virtual Machine
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===------------------------------------------------------------------------===#
+
+# Build GTest. We don't use a pre-built version due to
+# https://github.com/google/googletest/blob/master/googletest/docs/FAQ.md#why-is-it-not-recommended-to-install-a-pre-compiled-copy-of-google-test-for-example-into-usrlocal
+set(GTEST_SRC_DIR
+  "/usr/src/gtest"
+  CACHE
+  PATH
+  "Path to GTest source directory"
+)
+
+if (NOT EXISTS "${GTEST_SRC_DIR}")
+  message(FATAL_ERROR "GTest source directory \"${GTEST_SRC_DIR}\" cannot be found.\n"
+    "Try passing -DGTEST_SRC_DIR=<path_to_gtest_source> to cmake where "
+    "<path_to_gtest_source> is the path to the GoogleTest source tree.\n"
+    "Alternatively you can disable unit tests by passing "
+    "-DENABLE_UNIT_TESTS=OFF to cmake.")
+endif()
+
+# It's important that GTest is built with KLEE's compile flags
+# so set them here.
+set(_OLD_CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+foreach (f ${KLEE_COMPONENT_CXX_FLAGS})
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${f}")
+endforeach()
+foreach (f ${KLEE_COMPONENT_CXX_DEFINES})
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${f}")
+endforeach()
+
+# Build GTest as part of our project
+# FIXME: Prevent GTest from adding to our install target.
+# This is a problem for GTest >= 1.8. I've filled a PR to fix the issue
+# ( https://github.com/google/googletest/pull/921 ). If it gets accepted
+# we can do `set(gtest_enable_install FALSE)` to fix this.
+add_subdirectory(${GTEST_SRC_DIR} "${CMAKE_CURRENT_BINARY_DIR}/gtest_build")
+
+set(CMAKE_CXX_FLAGS "${_OLD_CMAKE_CXX_FLAGS}") # Restore the flags
+
+# This keeps track of all the unit test
+# targets so we can ensure they are built
+# before trying to run them.
+define_property(GLOBAL
+  PROPERTY KLEE_UNIT_TEST_TARGETS
+  BRIEF_DOCS "KLEE unit tests"
+  FULL_DOCS "KLEE unit tests"
+)
+
+set(GTEST_INCLUDE_DIR "${GTEST_SRC_DIR}/include")
+
+if (NOT IS_DIRECTORY "${GTEST_INCLUDE_DIR}")
+  message(FATAL_ERROR
+    "Cannot find GTest include directory \"${GTEST_INCLUDE_DIR}\"")
+endif()
+
+function(add_klee_unit_test target_name)
+  add_executable(${target_name} ${ARGN})
+  target_link_libraries(${target_name} PRIVATE gtest_main)
+  target_include_directories(${target_name} BEFORE PRIVATE "${GTEST_INCLUDE_DIR}")
+  set_target_properties(${target_name}
+    PROPERTIES
+    RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/unittests/"
+  )
+  set_property(GLOBAL
+    APPEND
+    PROPERTY KLEE_UNIT_TEST_TARGETS
+    ${target_name}
+  )
+endfunction()
+
+# Unit Tests
+add_subdirectory(Assignment)
+add_subdirectory(Expr)
+add_subdirectory(Ref)
+add_subdirectory(Solver)
+
+# Set up lit configuration
+set (UNIT_TEST_EXE_SUFFIX "Test")
+configure_file(lit-unit-tests-common.site.cfg.in
+  ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
+  @ONLY)
+
+# Add a target to run all the unit tests using lit
+get_property(UNIT_TEST_DEPENDS
+  GLOBAL
+  PROPERTY KLEE_UNIT_TEST_TARGETS
+)
+add_custom_target(unittests
+  COMMAND
+    "${LIT_TOOL}" ${LIT_ARGS} "${CMAKE_CURRENT_BINARY_DIR}"
+    DEPENDS ${UNIT_TEST_DEPENDS}
+    COMMENT "Running unittests"
+    ${ADD_CUSTOM_COMMAND_USES_TERMINAL_ARG}
+)
diff --git a/unittests/Expr/CMakeLists.txt b/unittests/Expr/CMakeLists.txt
new file mode 100644
index 00000000..4e7bc997
--- /dev/null
+++ b/unittests/Expr/CMakeLists.txt
@@ -0,0 +1,6 @@
+add_klee_unit_test(ExprTest
+  ExprTest.cpp)
+# FIXME: KLEE's libraries should just declare what libraries
+# they depend on so we don't need to manually link.
+klee_get_llvm_libs(LLVM_LIBS Support)
+target_link_libraries(ExprTest PRIVATE kleaverExpr ${LLVM_LIBS})
diff --git a/unittests/Ref/CMakeLists.txt b/unittests/Ref/CMakeLists.txt
new file mode 100644
index 00000000..d678930c
--- /dev/null
+++ b/unittests/Ref/CMakeLists.txt
@@ -0,0 +1,6 @@
+add_klee_unit_test(RefTest
+  RefTest.cpp)
+# FIXME: KLEE's libraries should just declare what libraries
+# they depend on so we don't need to manually link.
+klee_get_llvm_libs(LLVM_LIBS Support)
+target_link_libraries(RefTest PRIVATE kleaverExpr ${LLVM_LIBS})
diff --git a/unittests/Solver/CMakeLists.txt b/unittests/Solver/CMakeLists.txt
new file mode 100644
index 00000000..602a1196
--- /dev/null
+++ b/unittests/Solver/CMakeLists.txt
@@ -0,0 +1,12 @@
+add_klee_unit_test(SolverTest
+  SolverTest.cpp)
+# FIXME: KLEE's libraries should just declare what libraries
+# they depend on so we don't need to manually link.
+klee_get_llvm_libs(LLVM_LIBS Support)
+target_link_libraries(SolverTest
+  PRIVATE
+  kleaverSolver
+  kleaverExpr
+  kleeSupport
+  kleeBasic
+  ${LLVM_LIBS})
diff --git a/unittests/lit-unit-tests-common.cfg b/unittests/lit-unit-tests-common.cfg
new file mode 100644
index 00000000..57663ff7
--- /dev/null
+++ b/unittests/lit-unit-tests-common.cfg
@@ -0,0 +1,11 @@
+# Configuration file for the 'lit' test runner.
+
+import os
+
+import lit.formats
+
+# suffixes: A list of file extensions to treat as test files.
+config.suffixes = []
+
+# testFormat: The test format to use to interpret tests.
+config.test_format = lit.formats.GoogleTest('.', config.unit_test_exe_suffix)
diff --git a/unittests/lit-unit-tests-common.site.cfg.in b/unittests/lit-unit-tests-common.site.cfg.in
new file mode 100644
index 00000000..f106152f
--- /dev/null
+++ b/unittests/lit-unit-tests-common.site.cfg.in
@@ -0,0 +1,9 @@
+import sys
+import os
+
+## @AUTO_GEN_MSG@
+config.name = 'KLEE Unit tests'
+config.unit_test_exe_suffix = "@UNIT_TEST_EXE_SUFFIX@"
+
+# Let the main config do the real work.
+lit_config.load_config(config, "@CMAKE_SOURCE_DIR@/unittests/lit-unit-tests-common.cfg")