cmake: cleanup logic that sets flags per target/subdir

The previous logic that used a COMMON_*_FLAGS intermediate variable
and then re-assigned CMAKE_*_FLAGS before including each subdirectory
was confusing and ugly. This PR is the right way to do it.

This commit is purely refactoring: built binaries unchanged.

2 files changed, 36 insertions, 32 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 63d39ca75..964cd1fe2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -261,17 +261,10 @@ option(STACK_TRACE "Install a hook that dumps stack on exception" ${DEFAULT_STAC
 
 if(STACK_TRACE)
   message(STATUS "Stack trace on exception enabled")
-  # Don't set CMAKE_*_FLAGS directly or add_definitions, because this flag must
-  # not be set for tests targets (TODO: per-target logic into nested CMakeLists)
-  set(STACK_TRACE_C_FLAG "-DSTACK_TRACE")
-  if (STATIC)
-    set(STACK_TRACE_LINK_FLAG "-Wl,--wrap=__cxa_throw")
-  endif()
 else()
   message(STATUS "Stack trace on exception disabled")
 endif()
 
-
 if (UNIX AND NOT APPLE)
   # Note that at the time of this writing the -Wstrict-prototypes flag added below will make this fail
   set(THREADS_PREFER_PTHREAD_FLAG ON)
@@ -309,8 +302,8 @@ link_directories(${LIBUNWIND_LIBRARY_DIRS})
 
 if(MSVC)
   add_definitions("/bigobj /MP /W3 /GS- /D_CRT_SECURE_NO_WARNINGS /wd4996 /wd4345 /D_WIN32_WINNT=0x0600 /DWIN32_LEAN_AND_MEAN /DGTEST_HAS_TR1_TUPLE=0 /FIinline_c.h /D__SSE4_1__")
-  # set(COMMON_C_FLAGS "${COMMON_C_FLAGS} /Dinline=__inline")
-  set(COMMON_EXE_LINKER_FLAGS "${COMMON_EXE_LINKER_FLAGS} /STACK:10485760")
+  # set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /Dinline=__inline")
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /STACK:10485760")
   if(STATIC)
     foreach(VAR CMAKE_C_FLAGS_DEBUG CMAKE_CXX_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE CMAKE_CXX_FLAGS_RELEASE)
       string(REPLACE "/MD" "/MT" ${VAR} "${${VAR}}")
@@ -348,7 +341,7 @@ else()
     include_directories(SYSTEM src/platform/mingw)
     # mingw doesn't support LTO (multiple definition errors at link time)
     set(USE_LTO_DEFAULT false)
-    set(COMMON_EXE_LINKER_FLAGS "${COMMON_EXE_LINKER_FLAGS} -Wl,--stack,10485760")
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--stack,10485760")
     if(NOT BUILD_64)
       add_definitions(-DWINVER=0x0501 -D_WIN32_WINNT=0x0501)
     endif()
@@ -362,20 +355,20 @@ else()
     set(STATIC_ASSERT_FLAG "-Dstatic_assert=_Static_assert")
   endif()
 
-  set(COMMON_C_FLAGS "${COMMON_C_FLAGS} -std=c11 -D_GNU_SOURCE ${MINGW_FLAG} ${STATIC_ASSERT_FLAG} ${WARNINGS} ${C_WARNINGS} ${ARCH_FLAG}")
-  set(COMMON_CXX_FLAGS "${COMMON_CXX_FLAGS} -std=c++11 -D_GNU_SOURCE ${MINGW_FLAG} ${WARNINGS} ${CXX_WARNINGS} ${ARCH_FLAG}")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c11 -D_GNU_SOURCE ${MINGW_FLAG} ${STATIC_ASSERT_FLAG} ${WARNINGS} ${C_WARNINGS} ${ARCH_FLAG}")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -D_GNU_SOURCE ${MINGW_FLAG} ${WARNINGS} ${CXX_WARNINGS} ${ARCH_FLAG}")
 
   # With GCC 6.1.1 the compiled binary malfunctions due to aliasing. Until that
   # is fixed in the code (Issue #847), force compiler to be conservative.
-  set(COMMON_C_FLAGS "${COMMON_C_FLAGS} -fno-strict-aliasing")
-  set(COMMON_CXX_FLAGS "${COMMON_CXX_FLAGS} -fno-strict-aliasing")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-strict-aliasing")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-strict-aliasing")
 
   option(NO_AES "Explicitly disable AES support" ${NO_AES})
 
   if(NOT NO_AES AND NOT (ARM6 OR ARM7))
     message(STATUS "AES support enabled")
-    set(COMMON_C_FLAGS "${COMMON_C_FLAGS} -maes")
-    set(COMMON_CXX_FLAGS "${COMMON_CXX_FLAGS} -maes")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -maes")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -maes")
   elseif(ARM7 OR ARM6)
     message(STATUS "AES support disabled (not available on ARM)")
   else()
@@ -384,18 +377,18 @@ else()
 
   if(ARM6)
     message(STATUS "Setting ARM6 C and C++ flags")
-    set(COMMON_C_FLAGS "${COMMON_C_FLAGS} -mfpu=vfp -mfloat-abi=hard")
-    set(COMMON_CXX_FLAGS "${COMMON_CXX_FLAGS} -mfpu=vfp -mfloat-abi=hard")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mfpu=vfp -mfloat-abi=hard")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mfpu=vfp -mfloat-abi=hard")
   endif()
 
   if(ARM7)
     message(STATUS "Setting ARM7 C and C++ flags")
-    set(COMMON_C_FLAGS "${COMMON_C_FLAGS} -O2 -mfloat-abi=hard")
-    set(COMMON_CXX_FLAGS "${COMMON_CXX_FLAGS} -O2 -mfloat-abi=hard")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O2 -mfloat-abi=hard")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2 -mfloat-abi=hard")
   endif()
 
   if(APPLE)
-    set(COMMON_CXX_FLAGS "${COMMON_CXX_FLAGS} -DGTEST_HAS_TR1_TUPLE=0")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DGTEST_HAS_TR1_TUPLE=0")
   endif()
   if(CMAKE_C_COMPILER_ID STREQUAL "GNU" AND NOT (CMAKE_C_COMPILER_VERSION VERSION_LESS 4.8))
     set(DEBUG_FLAGS "-g3 -Og")
@@ -413,8 +406,8 @@ else()
     set(USE_LTO false)
     # explicitly define stdlib for older versions of clang
     if(CMAKE_C_COMPILER_VERSION VERSION_LESS 3.7)
-      set(COMMON_CXX_FLAGS "${COMMON_CXX_FLAGS} -stdlib=libc++")
-      set(COMMON_EXE_LINKER_FLAGS "${COMMON_EXE_LINKER_FLAGS} -stdlib=libc++")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
+      set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -stdlib=libc++")
     endif()
   endif()
 
@@ -437,7 +430,7 @@ else()
   set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} ${RELEASE_FLAGS}")
 
   if(STATIC AND NOT APPLE AND NOT FREEBSD AND NOT OPENBSD)
-    set(COMMON_EXE_LINKER_FLAGS "${COMMON_EXE_LINKER_FLAGS} -static-libgcc -static-libstdc++")
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static-libgcc -static-libstdc++")
   endif()
 endif()
 
@@ -486,22 +479,21 @@ endif()
 
 include(version.cmake)
 
-# When building the following sources treat warnings as errors, install throw wrapper
-set(CMAKE_C_FLAGS "${COMMON_C_FLAGS} ${WARNINGS_AS_ERRORS_FLAG} ${STACK_TRACE_C_FLAG}")
-set(CMAKE_CXX_FLAGS "${COMMON_CXX_FLAGS} ${WARNINGS_AS_ERRORS_FLAG} ${STACK_TRACE_C_FLAG}")
-set(CMAKE_EXE_LINKER_FLAGS "${COMMON_EXE_LINKER_FLAGS} ${STACK_TRACE_LINK_FLAG}")
+function (treat_warnings_as_errors dirs)
+  foreach(dir ${ARGV})
+    set_property(DIRECTORY ${dir}
+      APPEND PROPERTY COMPILE_FLAGS "-Werror")
+  endforeach()
+endfunction()
 
 add_subdirectory(contrib)
 add_subdirectory(src)
 
+treat_warnings_as_errors(contrib src)
 
 option(BUILD_TESTS "Build tests." OFF)
 
 if(BUILD_TESTS)
-  # When building tests, don't add some of the flags added to source build
-  set(CMAKE_C_FLAGS "${COMMON_C_FLAGS}")
-  set(CMAKE_CXX_FLAGS "${COMMON_CXX_FLAGS}")
-  set(CMAKE_EXE_LINKER_FLAGS "${COMMON_CXX_FLAGS}")
   add_subdirectory(tests)
 endif()
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e2349744d..8fa617aff 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -47,6 +47,17 @@ function (bitmonero_install_headers subdir)
     COMPONENT   development)
 endfunction ()
 
+function (enable_stack_trace target)
+  if(STACK_TRACE)
+    set_property(TARGET ${target}
+      APPEND PROPERTY COMPILER_DEFINITIONS "-DSTACK_TRACE")
+    if (STATIC)
+      set_property(TARGET "${target}"
+        APPEND PROPERTY LINK_FLAGS "-Wl,--wrap=__cxa_throw")
+    endif()
+  endif()
+endfunction()
+
 function (bitmonero_add_executable name)
   source_group("${name}"
     FILES
@@ -63,6 +74,7 @@ function (bitmonero_add_executable name)
   set_property(TARGET "${name}"
     PROPERTY
       RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+  enable_stack_trace("${name}")
 endfunction ()
 
 function (bitmonero_add_library name)