On Fri, Jan 29, 2021 at 12:57 PM Jakub Jelinek <jakub@xxxxxxxxxx> wrote: > > On Fri, Jan 29, 2021 at 12:48:11PM -0800, Nick Desaulniers wrote: > > > Should this be...? > > > > > > KBUILD_AFLAGS += -Wa,-gdwarf-5 > > > > No; under the set of conditions Clang is compiling .c to .S with DWARF > > v5 assembler directives. GAS will choke unless told -gdwarf-5 via > > -Wa,-gdwarf-5 for .c source files, hence it is a C flag, not an A > > Wasn't that fixed in GAS? > https://sourceware.org/bugzilla/show_bug.cgi?id=27195 ``` diff --git a/Makefile b/Makefile index bed8b3b180b8..de616e584706 100644 --- a/Makefile +++ b/Makefile @@ -835,17 +835,6 @@ dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4 dwarf-version-$(CONFIG_DEBUG_INFO_DWARF5) := 5 DEBUG_CFLAGS += -gdwarf-$(dwarf-version-y) -# If using clang without the integrated assembler, we need to explicitly tell -# GAS that we will be feeding it DWARF v5 assembler directives. Kconfig should -# detect whether the version of GAS supports DWARF v5. -ifdef CONFIG_CC_IS_CLANG -ifneq ($(LLVM_IAS),1) -ifeq ($(dwarf-version-y),5) -DEBUG_CFLAGS += -Wa,-gdwarf-5 -endif -endif -endif - ifdef CONFIG_DEBUG_INFO_REDUCED DEBUG_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ $(call cc-option,-fno-var-tracking) ``` $ make LLVM=1 -j72 defconfig $ ./scripts/config -e DEBUG_INFO -e DEBUG_INFO_DWARF5 $ make LLVM=1 -j72 ... /tmp/init-d50d89.s: Assembler messages: /tmp/init-d50d89.s:10: Error: file number less than one /tmp/init-d50d89.s:11: Error: junk at end of line, first unrecognized character is `m' which is https://sourceware.org/bugzilla/show_bug.cgi?id=25611. $ as --version | head -n1 GNU assembler (GNU Binutils for Debian) 2.35.1 Maybe GAS should not need to be told -gdwarf-5 to parse these? Then we would not need to pass -Wa,-gdwarf-5 via clang with -no-integrated-as. -- Thanks, ~Nick Desaulniers
