Always enable pie for gcc (#17567)

Ubuntu's GCC enables pie by default and it turns out we can't build with
it disabled. Just force it to be enabled for now.

Author: RossBrunton

CMakeLists.txt

@@ -1,16 +1,24 @@
-# Copyright (C) 2022-2023 Intel Corporation
+# Copyright (C) 2022-2025 Intel Corporation
 # Part of the Unified-Runtime Project, under the Apache License v2.0 with LLVM Exceptions.
 # See LICENSE.TXT
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 cmake_minimum_required(VERSION 3.20.0 FATAL_ERROR)
 project(unified-runtime VERSION 0.12.0)
+cmake_policy(SET CMP0083 NEW) # PROPERTY POSITION_INDEPENDENT_CODE
 
 # Check if unified runtime is built as a standalone project.
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR UR_STANDALONE_BUILD)
     set(UR_STANDALONE_BUILD TRUE)
 endif()
 
+# Ubuntu's gcc uses --enable-default-pie. For the sake of a consistent build
+# across different gcc versions, set it globally for all targets
+# https://wiki.ubuntu.com/ToolChain/CompilerFlags#A-fPIE
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+endif()
+
 include(GNUInstallDirs)
 include(CheckCXXSourceCompiles)
 include(CMakePackageConfigHelpers)
@@ -151,9 +159,6 @@ if(UR_ENABLE_TRACING)
 
         FetchContent_MakeAvailable(xpti)
 
-        # set -fPIC for xpti since we are linking it with a shared library
-        set_target_properties(xpti PROPERTIES POSITION_INDEPENDENT_CODE ON)
-
         # fetch the xptifw dispatcher, mostly used for testing
         # these variables need to be set for xptifw to compile
         set(XPTI_SOURCE_DIR ${xpti_SOURCE_DIR})

cmake/helpers.cmake

@@ -99,7 +99,6 @@ function(add_ur_target_compile_options name)
             -Wunused-parameter
 
             # Hardening options
-            -fPIC
             -fstack-protector-strong
             -fvisibility=hidden
 
@@ -172,15 +171,7 @@ function(add_ur_target_link_options name)
 endfunction()
 
 function(add_ur_target_exec_options name)
-    if(NOT MSVC)
-        if(NOT APPLE)
-            if(CMAKE_BUILD_TYPE STREQUAL "Release")
-                target_link_options(${name} PRIVATE
-                    $<$<CXX_COMPILER_ID:GNU>:-pie>
-                )
-            endif()
-        endif()
-    elseif(MSVC)
+    if(MSVC)
         target_link_options(${name} PRIVATE
             LINKER:/ALLOWISOLATION
         )