Provide a way to selectively enable assertions in release mode

- Throwing an assertion exception for proper stack unwinding, making
  sure destructors are called

- On in Debug mode, in Release, enable via:

      cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_ASSERTIONS=ON

Current problem that I'm seeing is that some code is not catching
exceptions or worse silently swallowing them. Would like to check the
whole pipeline before merging this in.

CMakeLists.txt

@@ -32,6 +32,7 @@ endif()
 option(ENABLE_JSON_LOGGING "Adds additional JSON debug logging to the response" OFF)
 option(DEBUG_GEOMETRY "Enables an option to dump GeoJSON of the final routing graph" OFF)
 option(BUILD_TOOLS "Build OSRM tools" OFF)
+option(ENABLE_ASSERTIONS OFF)
 
 include_directories(BEFORE ${CMAKE_CURRENT_BINARY_DIR}/include/)
 include_directories(BEFORE ${CMAKE_CURRENT_SOURCE_DIR}/include/)
@@ -97,6 +98,7 @@ if(NOT CMAKE_BUILD_TYPE MATCHES Debug)
 endif()
 if(CMAKE_BUILD_TYPE MATCHES Debug)
   message(STATUS "Configuring OSRM in debug mode")
+  set(ENABLE_ASSERTIONS ON)
   if(NOT ${CMAKE_CXX_COMPILER_ID} STREQUAL "MSVC")
 
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-inline -fno-omit-frame-pointer")
@@ -366,6 +368,11 @@ if(BUILD_TOOLS)
   install(TARGETS osrm-springclean DESTINATION bin)
 endif()
 
+if (ENABLE_ASSERTIONS)
+  message(STATUS "Enabling assertions")
+  add_definitions(-DBOOST_ENABLE_ASSERT_HANDLER)
+endif()
+
 # Add RPATH info to executables so that when they are run after being installed
 # (i.e., from /usr/local/bin/) the linker can find library dependencies. For
 # more info see http://www.cmake.org/Wiki/CMake_RPATH_handling

include/util/assert.hpp

@@ -0,0 +1,20 @@
+#ifndef OSRM_ASSERT_HPP
+#define OSRM_ASSERT_HPP
+
+#include <boost/assert.hpp>
+
+#include <stdexcept>
+
+namespace osrm
+{
+namespace util
+{
+// Assertion type to be thrown for stack unwinding
+struct assertionError final : std::logic_error
+{
+    assertionError(const char *msg) : std::logic_error{msg} {}
+};
+}
+}
+
+#endif

src/util/assert.cpp

@@ -0,0 +1,29 @@
+#include "util/assert.hpp"
+
+#include <sstream>
+
+namespace
+{
+// We throw to guarantee for stack-unwinding and therefore our destructors being called.
+void assertion_failed_msg_helper(
+    char const *expr, char const *msg, char const *function, char const *file, long line)
+{
+    std::ostringstream fmt;
+    fmt << file << ":" << line << "\nin: " << function << ": " << expr << "\n" << msg;
+    throw osrm::util::assertionError{fmt.str().c_str()};
+}
+}
+
+// Boost.Assert only declares the following two functions and let's us define them here.
+namespace boost
+{
+void assertion_failed(char const *expr, char const *function, char const *file, long line)
+{
+    ::assertion_failed_msg_helper(expr, "", function, file, line);
+}
+void assertion_failed_msg(
+    char const *expr, char const *msg, char const *function, char const *file, long line)
+{
+    ::assertion_failed_msg_helper(expr, msg, function, file, line);
+}
+}