On Thu, Jan 14, 2021 at 12:27 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > Sedat, > Thanks for testing, and congrats on https://lwn.net/Articles/839772/. > I always appreciate you taking the time to help test my work, and > other Clang+Linux kernel patches! > Hi Nick, cool, again in the top 15 :-). I should ask Mr. Corbet for a LWN subscription. > On Wed, Jan 13, 2021 at 1:24 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > > > On Wed, Jan 13, 2021 at 1:32 AM Nick Desaulniers > > <ndesaulniers@xxxxxxxxxx> wrote: > > > > > > --- a/Makefile > > > +++ b/Makefile > > > @@ -826,12 +826,16 @@ else > > > DEBUG_CFLAGS += -g > > > endif > > > > > > -ifneq ($(LLVM_IAS),1) > > > -KBUILD_AFLAGS += -Wa,-gdwarf-2 > > > +dwarf-version-$(CONFIG_DEBUG_INFO_DWARF2) := 2 > > > +dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4 > > > +DEBUG_CFLAGS += -gdwarf-$(dwarf-version-y) > > ^ DEBUG_CFLAGS are set for everyone (all toolchains) if > CONFIG_DEBUG_INFO is defined. > > > > +ifneq ($(dwarf-version-y)$(LLVM_IAS),21) > > ^ "If not using dwarf 2 and LLVM_IAS=1", ie. CONFIG_DEBUG_INFO_DWARF5 > && CONFIG_CC_IS_GCC > OK, I know DWARF v2 and LLVM_IAS=1 is broken. Looks like DWARF v5 with GCC v10.2.1 and binutils v2.35.1 is currently (here) no good choice. > > > +# Binutils 2.35+ required for -gdwarf-4+ support. > > > +dwarf-aflag := $(call as-option,-Wa$(comma)-gdwarf-$(dwarf-version-y)) > > > +ifdef CONFIG_CC_IS_CLANG > > ^ "if clang" > > > > +DEBUG_CFLAGS += $(dwarf-aflag) > > > endif > > > > Why is that "ifdef CONFIG_CC_IS_CLANG"? > > That's what Arvind requested on v2, IIUC: > https://lore.kernel.org/lkml/X8psgMuL4jMjP%2FOy@xxxxxxxxxxxxxxxxxx/ > > > When I use GCC v10.2.1 DEBUG_CFLAGS are not set. > > You should have -gdwarf-4 (and not -Wa,-gwarf-4) set for DEBUG_CFLAGS > when compiling with GCC and enabling CONFIG_DEBUG_INFO_DWARF4. Can you > please confirm? (Perhaps you may have accidentally disabled > CONFIG_DEBUG_INFO by rerunning `make defconfig`?) > $ egrep 'CC_IS_|LD_IS|BTF|DWARF' config-5.11.0-rc3-5-amd64-gcc10-llvm11 | grep ^CONFIG CONFIG_CC_IS_GCC=y CONFIG_LD_IS_LLD=y CONFIG_DEBUG_INFO_DWARF4=y CONFIG_DEBUG_INFO_BTF=y CONFIG_DEBUG_INFO_BTF_MODULES=y $ grep '\-Wa,-gdwarf-4' build-log_5.11.0-rc3-5-amd64-gcc10-llvm11.txt | wc -l 156
