| Message ID | 20200505141218.684079-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: use ARM unwinder for gcov | expand |
On Tue, May 05, 2020 at 04:11:56PM +0200, Arnd Bergmann wrote: > Using gcov on ARM fails when the frame pointer unwinder is used: > > arm-linux-gnueabi-ld: kernel/softirq.o:(.ARM.exidx+0x120): undefined reference to `__aeabi_unwind_cpp_pr0' > arm-linux-gnueabi-ld: init/main.o:(.ARM.exidx+0x98): undefined reference to `__aeabi_unwind_cpp_pr0' > arm-linux-gnueabi-ld: init/version.o:(.ARM.exidx+0x0): undefined reference to `__aeabi_unwind_cpp_pr0' > arm-linux-gnueabi-ld: init/do_mounts.o:(.ARM.exidx+0x28): undefined reference to `__aeabi_unwind_cpp_pr0' > arm-linux-gnueabi-ld: init/do_mounts_initrd.o:(.ARM.exidx+0x0): undefined reference to `__aeabi_unwind_cpp_pr0' > arm-linux-gnueabi-ld: init/initramfs.o:(.ARM.exidx+0x8): more undefined references to `__aeabi_unwind_cpp_pr0' follow > > This is likely a bug in clang that should be fixed in the compiler. > Forcing the use of the ARM unwinder in this configuration however > works around the problem. Or should the stub functions in arch/arm/kernel/unwind.c be moved out?
On Tue, May 5, 2020 at 4:19 PM Russell King - ARM Linux admin <linux@armlinux.org.uk> wrote: > > On Tue, May 05, 2020 at 04:11:56PM +0200, Arnd Bergmann wrote: > > Using gcov on ARM fails when the frame pointer unwinder is used: > > > > arm-linux-gnueabi-ld: kernel/softirq.o:(.ARM.exidx+0x120): undefined reference to `__aeabi_unwind_cpp_pr0' > > arm-linux-gnueabi-ld: init/main.o:(.ARM.exidx+0x98): undefined reference to `__aeabi_unwind_cpp_pr0' > > arm-linux-gnueabi-ld: init/version.o:(.ARM.exidx+0x0): undefined reference to `__aeabi_unwind_cpp_pr0' > > arm-linux-gnueabi-ld: init/do_mounts.o:(.ARM.exidx+0x28): undefined reference to `__aeabi_unwind_cpp_pr0' > > arm-linux-gnueabi-ld: init/do_mounts_initrd.o:(.ARM.exidx+0x0): undefined reference to `__aeabi_unwind_cpp_pr0' > > arm-linux-gnueabi-ld: init/initramfs.o:(.ARM.exidx+0x8): more undefined references to `__aeabi_unwind_cpp_pr0' follow > > > > This is likely a bug in clang that should be fixed in the compiler. > > Forcing the use of the ARM unwinder in this configuration however > > works around the problem. > > Or should the stub functions in arch/arm/kernel/unwind.c be moved out? I had not realized this is only a stub. Moving them out should fix the link failure, I can send a patch after testing if we are sure that calling them is not a bug in clang that would lead to runtime failures. Arnd
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug index a1dfb04231fd..41ef58acabf7 100644 --- a/arch/arm/Kconfig.debug +++ b/arch/arm/Kconfig.debug @@ -56,7 +56,7 @@ choice config UNWINDER_FRAME_POINTER bool "Frame pointer unwinder" - depends on !THUMB2_KERNEL + depends on !THUMB2_KERNEL && !(CC_IS_CLANG && GCOV_KERNEL) select ARCH_WANT_FRAME_POINTERS select FRAME_POINTER help
Using gcov on ARM fails when the frame pointer unwinder is used: arm-linux-gnueabi-ld: kernel/softirq.o:(.ARM.exidx+0x120): undefined reference to `__aeabi_unwind_cpp_pr0' arm-linux-gnueabi-ld: init/main.o:(.ARM.exidx+0x98): undefined reference to `__aeabi_unwind_cpp_pr0' arm-linux-gnueabi-ld: init/version.o:(.ARM.exidx+0x0): undefined reference to `__aeabi_unwind_cpp_pr0' arm-linux-gnueabi-ld: init/do_mounts.o:(.ARM.exidx+0x28): undefined reference to `__aeabi_unwind_cpp_pr0' arm-linux-gnueabi-ld: init/do_mounts_initrd.o:(.ARM.exidx+0x0): undefined reference to `__aeabi_unwind_cpp_pr0' arm-linux-gnueabi-ld: init/initramfs.o:(.ARM.exidx+0x8): more undefined references to `__aeabi_unwind_cpp_pr0' follow This is likely a bug in clang that should be fixed in the compiler. Forcing the use of the ARM unwinder in this configuration however works around the problem. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/arm/Kconfig.debug | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)