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Add this flag explicitly. >> +ifdef CONFIG_CC_IS_CLANG >> +DEBUG_CFLAGS += -grecord-gcc-switches >> +endif >> + > > This adds ~5MB/1% to vmlinux of an x86_64 defconfig built with clang. Do we > want to add additional guards for CONFIG_DEBUG_INFO_BTF, so that we don't have > to pay that cost if that config is not set? Since this patch is mostly motivated to detect whether the kernel is built with clang lto or not. Let me add the flag only if lto is enabled. My measurement shows 0.5% increase to thinlto-vmlinux. The smaller percentage is due to larger .debug_info section (almost double) for thinlto vs. no lto. ifdef CONFIG_LTO_CLANG DEBUG_CFLAGS += -grecord-gcc-switches endif This will make pahole with any clang built kernels, lto or non-lto. If the maintainer wants further restriction with CONFIG_DEBUG_INFO_BTF, I can do that in another revision.