Thread (8 messages) 8 messages, 4 authors, 2021-08-05

Re: [PATCH] scripts/Makefile.clang: default to LLVM_IAS=1

From: Nick Desaulniers <hidden>
Date: 2021-08-05 18:40:34
Also in: linux-kbuild, linux-riscv, lkml

On Thu, Aug 5, 2021 at 8:16 AM Masahiro Yamada [off-list ref] wrote:
On Tue, Aug 3, 2021 at 8:43 AM Nick Desaulniers [off-list ref] wrote:
quoted
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")
-- 
Thanks,
~Nick Desaulniers
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