From d7daf98db88e9e8b47bf27c5328b42c9499f1d9f Mon Sep 17 00:00:00 2001
From: olszomal <Malgorzata.Olszowka@stunnel.org>
Date: Fri, 29 Jul 2022 13:58:39 +0200
Subject: [PATCH] improve add compile and linker flags

---
 cmake/SetCompilerFlags.cmake | 143 ++++++++++++++++++++++-------------
 1 file changed, 92 insertions(+), 51 deletions(-)

diff --git a/cmake/SetCompilerFlags.cmake b/cmake/SetCompilerFlags.cmake
index 98a1694..edfc3a4 100644
--- a/cmake/SetCompilerFlags.cmake
+++ b/cmake/SetCompilerFlags.cmake
@@ -1,61 +1,99 @@
 include(CheckCCompilerFlag)
 
-function(add_compile_flags_target target)
-  if (CMAKE_C_COMPILER_ID MATCHES "Clang|AppleClang|GNU" )
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-ggdb -g>)
+function(add_linker_flag_if_supported flagname targets)
+  check_c_compiler_flag("${flagname}" HAVE_FLAG_${flagname})
+  if (HAVE_FLAG_${flagname})
+    foreach(target ${targets})
+      target_link_options(${target} PRIVATE ${flagname})
+    endforeach()
   endif()
+endfunction()
 
-  if(CMAKE_C_COMPILER_ID MATCHES "GNU|Clang")
+function(add_compile_flag_if_supported flagname targets)
+  check_c_compiler_flag("${flagname}" HAVE_FLAG_${flagname})
+  if (HAVE_FLAG_${flagname})
+    foreach(target ${targets})
+      target_compile_options(${target} PRIVATE ${flagname})
+    endforeach()
+  endif()
+endfunction()
+
+function(add_linker_flag_to_targets targets)
+  set(CHECKED_FLAGS
+    "-fstack-protector-all"
+    "-fstack-protector"
+    "-fstack-check"
+    "-fPIE"
+    "-pie"
+    "-Wl,-z,relro"
+    "-Wl,-z,now"
+    "-Wl,-z,noexecstack"
+  )
+  foreach(flag ${CHECKED_FLAGS})
+    add_linker_flag_if_supported(${flag} "${targets}")
+  endforeach()
+endfunction()
+
+function(add_debug_flag_if_supported flagname targets)
+  check_c_compiler_flag("${flagname}" HAVE_FLAG_${flagname})
+  if (HAVE_FLAG_${flagname})
+    foreach(target ${targets})
+      target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:${flagname}>)
+    endforeach()
+  endif()
+endfunction()
+
+function(add_compile_flag_to_targets targets)
+  set(CHECKED_FLAGS
     # Support address space layout randomization (ASLR)
-    target_compile_options(${target} PRIVATE -fPIE)
-    check_c_compiler_flag("-fstack-protector-all"  HAVE_STACK_PROTECTOR_ALL)
-    if(HAVE_STACK_PROTECTOR_ALL)
-      target_link_options(${target} PRIVATE -fstack-protector-all)
-    else()
-      check_c_compiler_flag("-fstack-protector"    HAVE_STACK_PROTECTOR)
-      if(HAVE_STACK_PROTECTOR)
-        target_link_options(${target} PRIVATE -fstack-protector)
-      else()
-        message(WARNING "No stack protection supported")
-      endif()
-    endif()
-    target_link_options(${target} PRIVATE -fstack-check)
-    #target_link_options(${target} PRIVATE -fPIE -pie)
-    #target_link_options(${target} PRIVATE -Wl,-z,relro)
-    #target_link_options(${target} PRIVATE -Wl,-z,now)
-    #target_link_options(${target} PRIVATE -Wl,-z,noexecstack)
-
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-O2>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-pedantic>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wno-long-long>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wconversion>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-D_FORTIFY_SOURCE=2>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wformat=2>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wundef>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wshadow>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wredundant-decls>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wcast-qual>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wnull-dereference>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wmissing-declarations>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wmissing-prototypes>)
-  endif()
-
-  if(CMAKE_C_COMPILER_ID MATCHES "GNU")
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wall>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wextra>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wno-deprecated-declarations>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wstrict-aliasing=3>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wstrict-overflow=2>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wlogical-op>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wwrite-strings>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wcast-align=strict>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wdisabled-optimization>)
-    target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:-Wshift-overflow=2>)
-  endif()
+    "-fPIE"
+  )
+  set(CHECKED_DEBUG_FLAGS
+    "-ggdb"
+    "-g"
+    "-O2"
+    "-pedantic"
+    "-Wall"
+    "-Wextra"
+    "-Wno-long-long"
+    "-Wconversion"
+    "-D_FORTIFY_SOURCE=2"
+    "-Wformat=2"
+    "-Wredundant-decls"
+    "-Wcast-qual"
+    "-Wnull-dereference"
+    "-Wno-deprecated-declarations"
+    "-Wmissing-declarations"
+    "-Wmissing-prototypes"
+    "-Wmissing-noreturn"
+    "-Wmissing-braces"
+    "-Wparentheses"
+    "-Wstrict-aliasing=3"
+    "-Wstrict-overflow=2"
+    "-Wlogical-op"
+    "-Wwrite-strings"
+    "-Wcast-align=strict"
+    "-Wdisabled-optimization"
+    "-Wshift-overflow=2"
+    "-Wundef"
+    "-Wshadow"
+    "-Wmisleading-indentation"
+    "-Wabsolute-value"
+    "-Wunused-parameter"
+    "-Wunused-function"
+  )
+  foreach(flag ${CHECKED_FLAGS})
+    add_compile_flag_if_supported(${flag} ${targets})
+  endforeach()
+  foreach(flag ${CHECKED_DEBUG_FLAGS})
+    add_debug_flag_if_supported(${flag} ${targets})
+  endforeach()
+endfunction()
 
+function(add_compile_flags target)
   if(MSVC)
     # Enable parallel builds
-    add_definitions(/MP)
+    target_compile_options(${target} PRIVATE /MP)
     # Use address space layout randomization, generate PIE code for ASLR (default on)
     target_link_options(${target} PRIVATE /DYNAMICBASE)
     # Create terminal server aware application (default on)
@@ -86,7 +124,10 @@ function(add_compile_flags_target target)
     target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:/D_FORTIFY_SOURCE=2>)
     # Unrecognized compiler options are errors
     target_compile_options(${target} PRIVATE $<$<CONFIG:DEBUG>:/options:strict>)
+  else()
+    add_linker_flag_to_targets(${target})
+    add_compile_flag_to_targets(${target})
   endif()
 endfunction()
 
-add_compile_flags_target(osslsigncode)
+add_compile_flags(osslsigncode)