On Fri, Aug 6, 2021 at 3:40 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > On Thu, Aug 5, 2021 at 8:16 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > > > On Tue, Aug 3, 2021 at 8:43 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > > > > > diff --git a/Makefile b/Makefile > > > index 444558e62cbc..b24b48c9ebb7 100644 > > > --- a/Makefile > > > +++ b/Makefile > > > @@ -845,7 +845,7 @@ else > > > DEBUG_CFLAGS += -g > > > endif > > > > > > -ifneq ($(LLVM_IAS),1) > > > +ifeq ($(LLVM_IAS),0) > > > KBUILD_AFLAGS += -Wa,-gdwarf-2 > > > endif > > > > > > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > > > index bc74afdbf31e..807f7c94bc6f 100644 > > > --- a/arch/riscv/Makefile > > > +++ b/arch/riscv/Makefile > > > @@ -41,7 +41,7 @@ endif > > > ifeq ($(CONFIG_LD_IS_LLD),y) > > > KBUILD_CFLAGS += -mno-relax > > > KBUILD_AFLAGS += -mno-relax > > > -ifneq ($(LLVM_IAS),1) > > > +ifeq ($(LLVM_IAS),0) > > > KBUILD_CFLAGS += -Wa,-mno-relax > > > KBUILD_AFLAGS += -Wa,-mno-relax > > > endif > > > > > > > > Please drop these two hunks. > > > > I will apply my patch instead. > > https://lore.kernel.org/patchwork/patch/1472580/ > > Sure. Will send a v2 with Matthew's suggestion as well. > > > When we negate a flag that is enabled by default, > > which is a common way? > > - set it to '0' > > - set is to empty > > > > > > So, I was wondering if we should support > > not only LLVM_IAS=0 but also LLVM_IAS=. > > > > What do you think? > > LLVM_IAS= looks weird (so I agree with Khem's response), but if it's > common/expected then maybe if there's a way to write a concise check > for either =<blank> or =0? I don't feel strongly about how it's > specified to disable the integrated assembler, but let's sort that out > _before_ I send a v2. > > How can you tell the difference between `make CC=clang` and `make > CC=clang LLVM_IAS=`? (maybe that doesn't matter here, as either imply > "don't use clang as the assembler when compiling with clang") $(origin LLVM_IAS) knows the difference. make CC=clang -> $(origin LLVM_IAS) is 'undefined' make CC=clang LLVM_IAS= -> $(origin LLVM_IAS) is 'command line' LLVM_IAS= make CC=clang -> $(origin LLVM_IAS) is 'environment' The following patch makes both LLVM_IAS= and LLVM_IAS=0 work for disabling the integrated assembler. @@ -22,6 +22,9 @@ else CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) endif # CROSS_COMPILE +# The integrated assembler is enabled by default. +LLVM_IAS ?= 1 + ifeq ($(LLVM_IAS),1) CLANG_FLAGS += -integrated-as else But, I am not pretty sure if it is a good idea... Perhaps, it is better to require LLVM_IAS=0 as Khem mentioned. Another way for avoiding ambiguity is, perhaps LLVM_IAS_DISABLE=1 instead of LLVM_IAS=0. -- Best Regards Masahiro Yamada
