[nrf fromlist] buildsystem: Enable LTO also for the application

Upstream PR: zephyrproject-rtos/zephyr#69519 It turns out that currently LTO is enabled only for the kernel. This commit updates it to enable it for the whole application and adds additional LTO exclusions required for the standard C libraries to build and link properly. Signed-off-by: Radosław Koppel <[email protected]>
nrfconnect · Mar 1, 2024 · 9448e2b · 9448e2b
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commit 9448e2b
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diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -214,7 +214,7 @@ endif()
 zephyr_compile_options(${OPTIMIZATION_FLAG})
 
 if(CONFIG_LTO)
-  add_compile_options($<TARGET_PROPERTY:compiler,optimization_lto>)
+  zephyr_compile_options($<TARGET_PROPERTY:compiler,optimization_lto>)
   add_link_options($<TARGET_PROPERTY:linker,lto_arguments>)
 endif()
 

diff --git a/lib/libc/newlib/CMakeLists.txt b/lib/libc/newlib/CMakeLists.txt
@@ -3,6 +3,9 @@
 zephyr_library()
 zephyr_library_sources(libc-hooks.c)
 
+# Do not allow LTO when compiling libc-hooks.c file
+set_source_files_properties(libc-hooks.c PROPERTIES COMPILE_OPTIONS $<TARGET_PROPERTY:compiler,prohibit_lto>)
+
 # Zephyr normally uses -ffreestanding, which with current GNU toolchains
 # means that the flag macros used by newlib 3.x <inttypes.h> to signal
 # support for PRI.64 macros are not present.  To make them available we

diff --git a/lib/libc/picolibc/CMakeLists.txt b/lib/libc/picolibc/CMakeLists.txt
@@ -3,6 +3,9 @@
 zephyr_library()
 zephyr_library_sources(libc-hooks.c)
 
+# Do not allow LTO when compiling libc-hooks.c file
+set_source_files_properties(libc-hooks.c PROPERTIES COMPILE_OPTIONS $<TARGET_PROPERTY:compiler,prohibit_lto>)
+
 # define __LINUX_ERRNO_EXTENSIONS__ so we get errno defines like -ESHUTDOWN
 # used by the network stack
 zephyr_compile_definitions(__LINUX_ERRNO_EXTENSIONS__)