0033399: Configuration - Research into opportunities to increase performance

Implement CMake profiles to modify compiler and linker flags

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5ef2cb161b204a23b45a54dd8f1baad05abfdb5b..86905287dc804eb1065dbe46c20ae7f2e13c4e3d 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,6 +39,10 @@ endmacro()
 set (USE_MMGR_TYPE "NATIVE" CACHE STRING "Select using memory manager tool.")
 set_property(CACHE USE_MMGR_TYPE PROPERTY STRINGS "NATIVE" "FLEXIBLE" "TBB" "JEMALLOC")
 
+# set profile for C++ compiler and linker
+set (BUILD_OPT_PROFILE "Default" CACHE STRING "Select profile for compiler and linker.")
+set_property(CACHE BUILD_OPT_PROFILE PROPERTY STRINGS "Default" "Production")
+
 # include variable description
 OCCT_INCLUDE_CMAKE_FILE ("adm/cmake/vardescr")
 

diff --git a/adm/cmake/occt_defs_flags.cmake b/adm/cmake/occt_defs_flags.cmake
index 33b50e8ce73769c9fecd7a629307424169264ccf..3d989abcd4365cf0a97ca0f642f28069eeb176dd 100644 (file)
--- a/adm/cmake/occt_defs_flags.cmake
+++ b/adm/cmake/occt_defs_flags.cmake
@@ -44,9 +44,25 @@ elseif (MSVC)
 endif()
 
 if (MSVC)
-  # string pooling (GF), function-level linking (Gy)
-  set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /GF /Gy")
-  set (CMAKE_C_FLAGS_RELEASE   "${CMAKE_C_FLAGS_RELEASE}   /GF /Gy")
+  if ("${BUILD_OPT_PROFILE}" STREQUAL "Production")
+    # string pooling (GF), function-level linking (Gy)
+    set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /GF /Gy")
+    set (CMAKE_C_FLAGS_RELEASE   "${CMAKE_C_FLAGS_RELEASE}   /GF /Gy")
+
+    # Favor fast code (Ot), Omit frame pointers (Oy)
+    set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Ot /Oy")
+    set (CMAKE_C_FLAGS_RELEASE   "${CMAKE_C_FLAGS_RELEASE}   /Ot /Oy")
+
+    # Whole Program Optimisation (GL), Enable intrinsic functions (Oi)
+    set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /GL /Oi")
+    set (CMAKE_C_FLAGS_RELEASE   "${CMAKE_C_FLAGS_RELEASE}   /GL /Oi")
+
+    # Link-Time Code Generation(LTCG) is requared for Whole Program Optimisation(GL)
+    set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /LTCG")
+    set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /LTCG")
+    set(CMAKE_STATIC_LINKER_FLAGS_RELEASE "${CMAKE_STATIC_LINKER_FLAGS_RELEASE} /LTCG")
+    set(CMAKE_MODULE_LINKER_FLAGS_RELEASE "${CMAKE_MODULE_LINKER_FLAGS_RELEASE} /LTCG")
+  endif()
   if (BUILD_FORCE_RelWithDebInfo)
     # generate debug info (Zi), inline expansion level (Ob1)
     set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Zi /Ob1")
@@ -118,6 +134,22 @@ if (MSVC)
   endif()
 elseif (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPILER_ID MATCHES "[Cc][Ll][Aa][Nn][Gg]"))
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
+
+  if ("${BUILD_OPT_PROFILE}" STREQUAL "Production")
+    # /Ot (favor speed over size) is similar to -O2 or -O3 in GCC/Clang.
+    # /Oy (omit frame pointers) is similar to -fomit-frame-pointer in GCC/Clang.
+    # /GL (whole program optimization) is similar to -flto (Link Time Optimization) in GCC/Clang.
+    # /GF (eliminate duplicate strings) doesn't have a direct equivalent in GCC/Clang, but the compilers do string pooling automatically.
+    # /Gy (enable function-level linking) is similar to -ffunction-sections in GCC/Clang.
+    # /fp:precise (improve floating-point consistency) is similar to -ffloat-store in GCC, but there isn't a perfect equivalent in Clang.
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3 -fomit-frame-pointer -flto -ffunction-sections -ffloat-store")
+
+    # Link-Time Code Generation(LTCG) is requared for Whole Program Optimisation(GL)
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -flto")
+    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -flto")
+    set(CMAKE_STATIC_LINKER_FLAGS "${CMAKE_STATIC_LINKER_FLAGS} -flto")
+    set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -flto")
+  endif()
   if (CMAKE_CXX_COMPILER_ID MATCHES "[Cc][Ll][Aa][Nn][Gg]")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wshorten-64-to-32")
   endif()