Enabled LTO (Link Time Optimization) except for gui.

- LTO-on causes a crash due to Qt used in gui library.

Signed-off-by: Jaehyun Kim <[email protected]>

Author: jhkim-pii

CMakeLists.txt

@@ -21,12 +21,6 @@ cmake_policy(SET CMP0077 NEW)
 # Let AUTOMOC and AUTOUIC process GENERATED files.
 cmake_policy(SET CMP0071 NEW)
 
-# Interfers with Qt so off by default.
-option(LINK_TIME_OPTIMIZATION "Flag to control link time optimization: off by default" OFF)
-
-if (LINK_TIME_OPTIMIZATION)
-set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
-endif()
 
 # Allow to use external shared boost libraries
 option(USE_SYSTEM_BOOST "Use system shared Boost libraries" OFF)
@@ -55,6 +49,15 @@ project(OpenROAD VERSION 1
   LANGUAGES CXX
 )
 
+# LTO setting must come after project() for proper compiler detection
+option(LINK_TIME_OPTIMIZATION "Flag to control link time optimization: on by default" ON)
+if (LINK_TIME_OPTIMIZATION)
+  set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
+  message(STATUS "LTO is enabled")
+else()
+  message(STATUS "LTO is disabled: ${LTO_ERROR}")
+endif()
+
 set(OPENROAD_HOME ${PROJECT_SOURCE_DIR})
 set(OPENROAD_SHARE ${CMAKE_INSTALL_PREFIX}/share/openroad)
 

src/gui/CMakeLists.txt

@@ -85,6 +85,9 @@ if (Qt5_FOUND AND BUILD_GUI)
       OpenSTA
   )
 
+  # Disable LTO for gui. LTO causes a crash with Qt plugin loading
+  set_target_properties(gui PROPERTIES INTERPROCEDURAL_OPTIMIZATION OFF)
+
 messages(
   TARGET gui
 )