nrfconnect · carlescufi · Feb 27, 2024 · Jan 10, 2024 · Dec 6, 2023 · Dec 6, 2023
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -213,6 +213,11 @@ endif()
 # Apply the final optimization flag(s)
 zephyr_compile_options(${OPTIMIZATION_FLAG})
 
+if(CONFIG_LTO)
+  add_compile_options($<TARGET_PROPERTY:compiler,optimization_lto>)
+  add_link_options($<TARGET_PROPERTY:linker,lto_arguments>)
+endif()
+
 # @Intent: Obtain compiler specific flags related to C++ that are not influenced by kconfig
 zephyr_compile_options($<$<COMPILE_LANGUAGE:CXX>:$<TARGET_PROPERTY:compiler-cpp,required>>)
 
@@ -803,6 +808,10 @@ target_include_directories(${OFFSETS_LIB} PRIVATE
   kernel/include
   ${ARCH_DIR}/${ARCH}/include
   )
+
+# Make sure that LTO will never be enabled when compiling offsets.c
+set_source_files_properties(${OFFSETS_C_PATH} PROPERTIES COMPILE_OPTIONS $<TARGET_PROPERTY:compiler,prohibit_lto>)
+
 target_link_libraries(${OFFSETS_LIB} zephyr_interface)
 add_dependencies(zephyr_interface
   ${SYSCALL_LIST_H_TARGET}
@@ -1226,10 +1235,11 @@ if(CONFIG_GEN_ISR_TABLES)
   # isr_tables.c is generated from ${ZEPHYR_LINK_STAGE_EXECUTABLE} by
   # gen_isr_tables.py
   add_custom_command(
-    OUTPUT isr_tables.c
+    OUTPUT isr_tables.c isr_tables_vt.ld isr_tables_swi.ld
     COMMAND ${PYTHON_EXECUTABLE}
     ${ZEPHYR_BASE}/scripts/build/gen_isr_tables.py
     --output-source isr_tables.c
+    --linker-output-files isr_tables_vt.ld isr_tables_swi.ld
     --kernel $<TARGET_FILE:${ZEPHYR_LINK_STAGE_EXECUTABLE}>
     --intlist-section .intList
     --intlist-section intList

diff --git a/Kconfig.zephyr b/Kconfig.zephyr
@@ -417,6 +417,13 @@ config NO_OPTIMIZATIONS
 	  default stack sizes in order to avoid stack overflows.
 endchoice
 
+config LTO
+	bool "Link Time Optimization [EXPERIMENTAL]"
+	depends on !(GEN_ISR_TABLES || GEN_IRQ_VECTOR_TABLE) || ISR_TABLES_LOCAL_DECLARATION
+	select EXPERIMENTAL
+	help
+	  This option enables Link Time Optimization.
+
 config COMPILER_WARNINGS_AS_ERRORS
 	bool "Treat warnings as errors"
 	help

diff --git a/arch/Kconfig b/arch/Kconfig
@@ -391,6 +391,29 @@ config NOCACHE_MEMORY
 
 menu "Interrupt Configuration"
 
+config ISR_TABLES_LOCAL_DECLARATION_SUPPORTED
+	bool
+	default y
+	# Userspace is currently not supported
+	depends on !USERSPACE
+	# List of currently supported architectures
+	depends on ARM || ARM64
+	# List of currently supported toolchains
+	depends on "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "zephyr" || "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "gnuarmemb"
+
+config ISR_TABLES_LOCAL_DECLARATION
+	bool "ISR tables created locally and placed by linker [EXPERIMENTAL]"
+	depends on ISR_TABLES_LOCAL_DECLARATION_SUPPORTED
+	select EXPERIMENTAL
+	help
+	  Enable new scheme of interrupt tables generation.
+	  This is totally different generator that would create tables entries locally
+	  where the IRQ_CONNECT macro is called and then use the linker script to position it
+	  in the right place in memory.
+	  The most important advantage of such approach is that the generated interrupt tables
+	  are LTO compatible.
+	  The drawback is that the support on the architecture port is required.
+
 config DYNAMIC_INTERRUPTS
 	bool "Installation of IRQs at runtime"
 	help

diff --git a/arch/arm/core/CMakeLists.txt b/arch/arm/core/CMakeLists.txt
@@ -34,3 +34,11 @@ else()
 zephyr_linker_sources(ROM_START SORT_KEY 0x0vectors vector_table.ld)
 zephyr_linker_sources(ROM_START SORT_KEY 0x1vectors cortex_m/vector_table_pad.ld)
 endif()
+
+if(CONFIG_GEN_SW_ISR_TABLE)
+  if(CONFIG_DYNAMIC_INTERRUPTS)
+    zephyr_linker_sources(RWDATA swi_tables.ld)
+  else()
+    zephyr_linker_sources(RODATA swi_tables.ld)
+  endif()
+endif()
diff --git a/arch/arm/core/swi_tables.ld b/arch/arm/core/swi_tables.ld
@@ -0,0 +1,8 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#if LINKER_ZEPHYR_FINAL && defined(CONFIG_ISR_TABLES_LOCAL_DECLARATION)
+INCLUDE isr_tables_swi.ld
+#endif
diff --git a/arch/arm/core/vector_table.ld b/arch/arm/core/vector_table.ld
@@ -51,6 +51,10 @@ _vector_start = .;
 KEEP(*(.exc_vector_table))
 KEEP(*(".exc_vector_table.*"))
 
+#if LINKER_ZEPHYR_FINAL && defined(CONFIG_ISR_TABLES_LOCAL_DECLARATION)
+INCLUDE isr_tables_vt.ld
+#else
 KEEP(*(.vectors))
+#endif
 
 _vector_end = .;
diff --git a/arch/arm64/core/CMakeLists.txt b/arch/arm64/core/CMakeLists.txt
@@ -55,3 +55,11 @@ if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
 endif()
 
 add_subdirectory_ifdef(CONFIG_XEN xen)
+
+if(CONFIG_GEN_SW_ISR_TABLE)
+  if(CONFIG_DYNAMIC_INTERRUPTS)
+    zephyr_linker_sources(RWDATA swi_tables.ld)
+  else()
+    zephyr_linker_sources(RODATA swi_tables.ld)
+  endif()
+endif()
diff --git a/arch/arm64/core/swi_tables.ld b/arch/arm64/core/swi_tables.ld
@@ -0,0 +1,8 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#if LINKER_ZEPHYR_FINAL && defined(CONFIG_ISR_TABLES_LOCAL_DECLARATION)
+INCLUDE isr_tables_swi.ld
+#endif
diff --git a/arch/common/CMakeLists.txt b/arch/common/CMakeLists.txt
@@ -39,6 +39,11 @@ zephyr_linker_sources_ifdef(CONFIG_GEN_ISR_TABLES
   ${ZEPHYR_BASE}/include/zephyr/linker/intlist.ld
 )
 
+zephyr_linker_sources_ifdef(CONFIG_ISR_TABLES_LOCAL_DECLARATION
+  SECTIONS
+  ${ZEPHYR_BASE}/include/zephyr/linker/isr-local-drop-unused.ld
+)
+
 zephyr_linker_sources_ifdef(CONFIG_GEN_IRQ_VECTOR_TABLE
   ROM_START
   SORT_KEY 0x0vectors

diff --git a/arch/common/isr_tables.c b/arch/common/isr_tables.c
@@ -15,15 +15,27 @@
 struct int_list_header {
 	uint32_t table_size;
 	uint32_t offset;
+#if IS_ENABLED(CONFIG_ISR_TABLES_LOCAL_DECLARATION)
+	uint32_t swi_table_entry_size;
+	uint32_t shared_isr_table_entry_size;
+	uint32_t shared_isr_client_num_offset;
+#endif /* IS_ENABLED(CONFIG_ISR_TABLES_LOCAL_DECLARATION) */
 };
 
 /* These values are not included in the resulting binary, but instead form the
  * header of the initList section, which is used by gen_isr_tables.py to create
  * the vector and sw isr tables,
  */
-Z_GENERIC_SECTION(.irq_info) struct int_list_header _iheader = {
+Z_GENERIC_SECTION(.irq_info) __used struct int_list_header _iheader = {
 	.table_size = IRQ_TABLE_SIZE,
 	.offset = CONFIG_GEN_IRQ_START_VECTOR,
+#if IS_ENABLED(CONFIG_ISR_TABLES_LOCAL_DECLARATION)
+	.swi_table_entry_size = sizeof(struct _isr_table_entry),
+#if IS_ENABLED(CONFIG_SHARED_INTERRUPTS)
+	.shared_isr_table_entry_size = sizeof(struct z_shared_isr_table_entry),
+	.shared_isr_client_num_offset = offsetof(struct z_shared_isr_table_entry, client_num),
+#endif /* IS_ENABLED(CONFIG_SHARED_INTERRUPTS) */
+#endif /* IS_ENABLED(CONFIG_ISR_TABLES_LOCAL_DECLARATION) */
 };
 
 /* These are placeholder tables. They will be replaced by the real tables

diff --git a/arch/common/shared_irq.c b/arch/common/shared_irq.c
@@ -20,7 +20,7 @@ void z_shared_isr(const void *data)
 {
 	size_t i;
 	const struct z_shared_isr_table_entry *entry;
-	const struct z_shared_isr_client *client;
+	const struct _isr_table_entry *client;
 
 	entry = data;
 
@@ -42,7 +42,7 @@ void z_isr_install(unsigned int irq, void (*routine)(const void *),
 {
 	struct z_shared_isr_table_entry *shared_entry;
 	struct _isr_table_entry *entry;
-	struct z_shared_isr_client *client;
+	struct _isr_table_entry *client;
 	unsigned int table_idx;
 	int i;
 	k_spinlock_key_t key;
@@ -103,10 +103,10 @@ void z_isr_install(unsigned int irq, void (*routine)(const void *),
 	k_spin_unlock(&lock, key);
 }
 
-static void swap_client_data(struct z_shared_isr_client *a,
-			     struct z_shared_isr_client *b)
+static void swap_client_data(struct _isr_table_entry *a,
+			     struct _isr_table_entry *b)
 {
-	struct z_shared_isr_client tmp;
+	struct _isr_table_entry tmp;
 
 	tmp.arg = a->arg;
 	tmp.isr = a->isr;
@@ -162,7 +162,7 @@ int z_isr_uninstall(unsigned int irq,
 {
 	struct z_shared_isr_table_entry *shared_entry;
 	struct _isr_table_entry *entry;
-	struct z_shared_isr_client *client;
+	struct _isr_table_entry *client;
 	unsigned int table_idx;
 	size_t i;
 	k_spinlock_key_t key;

diff --git a/cmake/bintools/gnu/target.cmake b/cmake/bintools/gnu/target.cmake
@@ -5,8 +5,13 @@
 find_program(CMAKE_OBJCOPY ${CROSS_COMPILE}objcopy PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
 find_program(CMAKE_OBJDUMP ${CROSS_COMPILE}objdump PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
 find_program(CMAKE_AS      ${CROSS_COMPILE}as      PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
-find_program(CMAKE_AR      ${CROSS_COMPILE}ar      PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
-find_program(CMAKE_RANLIB  ${CROSS_COMPILE}ranlib  PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
+if(CONFIG_LTO)
+  find_program(CMAKE_AR      ${CROSS_COMPILE}gcc-ar      PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
+  find_program(CMAKE_RANLIB  ${CROSS_COMPILE}gcc-ranlib  PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
+else()
+  find_program(CMAKE_AR      ${CROSS_COMPILE}ar      PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
+  find_program(CMAKE_RANLIB  ${CROSS_COMPILE}ranlib  PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
+endif()
 find_program(CMAKE_READELF ${CROSS_COMPILE}readelf PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
 find_program(CMAKE_NM      ${CROSS_COMPILE}nm      PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)
 find_program(CMAKE_STRIP   ${CROSS_COMPILE}strip   PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)

diff --git a/cmake/compiler/gcc/compiler_flags.cmake b/cmake/compiler/gcc/compiler_flags.cmake
@@ -21,6 +21,9 @@ endif()
 set_compiler_property(PROPERTY optimization_speed -O2)
 set_compiler_property(PROPERTY optimization_size  -Os)
 
+set_compiler_property(PROPERTY optimization_lto -flto)
+set_compiler_property(PROPERTY prohibit_lto -fno-lto)
+
 #######################################################
 # This section covers flags related to warning levels #
 #######################################################

diff --git a/cmake/linker/ld/linker_flags.cmake b/cmake/linker/ld/linker_flags.cmake
@@ -12,6 +12,8 @@ endif()
 
 set_property(TARGET linker PROPERTY partial_linking "-r")
 
+set_property(TARGET linker PROPERTY lto_arguments -flto -fno-ipa-sra -ffunction-sections -fdata-sections)
+
 # Some linker flags might not be purely ld specific, but a combination of
 # linker and compiler, such as:
 # --coverage for clang