net: Support no-lto option for the network build.

Add CONFIG_NET_NO_LTO to allow compiling the network stack with -fno-lto.
This is useful for avoiding LTO-related issues in the network layer.

Signed-off-by: daichuan <daichuan@xiaomi.com>

net/CMakeLists.txt

@@ -27,4 +27,8 @@ if(CONFIG_NET)
 
   target_sources(net PRIVATE net_initialize.c)
   target_include_directories(net PRIVATE ${CMAKE_CURRENT_LIST_DIR})
+
+  if(CONFIG_NET_NO_LTO)
+    add_compile_options(-fno-lto)
+  endif()
 endif()

net/Kconfig

@@ -457,4 +457,19 @@ endmenu # Network Topologies
 
 source "net/route/Kconfig"
 
+config NET_NO_LTO
+	bool "Support no-lto option for the network Makefile"
+	default n
+	---help---
+		This option disables Link Time Optimization (LTO) specifically for the
+		network subsystem.
+
+		LTO can sometimes introduce build issues, excessive compilation time,
+		or difficult-to-debug runtime behaviors in complex network stacks
+		depending on the compiler version and architecture.
+
+		Enable this option if you encounter LTO-related issues in the network
+		stack or need to debug network code without the aggressive optimizations
+		introduced by LTO, while keeping LTO enabled for the rest of the system.
+
 endif # NET

net/Makefile

@@ -70,6 +70,10 @@ COBJS = $(CSRCS:.c=$(OBJEXT))
 SRCS = $(ASRCS) $(CSRCS)
 OBJS = $(AOBJS) $(COBJS)
 
+ifeq ($(CONFIG_NET_NO_LTO),y)
+CFLAGS += -fno-lto
+endif
+
 BIN = libnet$(LIBEXT)
 
 all: $(BIN)