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* [PATCH] kbuild: add -fno-discard-value-names to cmd_cc_ll_c
@ 2022-10-07 20:32 Nick Desaulniers
  2022-10-13 19:56 ` Nathan Chancellor
  0 siblings, 1 reply; 7+ messages in thread
From: Nick Desaulniers @ 2022-10-07 20:32 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Michal Marek, Nathan Chancellor, Tom Rix, linux-kbuild,
	linux-kernel, llvm, Nick Desaulniers

When debugging LLVM IR, it can be handy for clang to not discard value
names used for local variables and parameters. Compare the generated IR.

Implicit Default (-fdiscard-value-names):
  define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) {
    %6 = alloca i64
    %7 = alloca %struct.poll_wqueues
    %8 = alloca [64 x i32]

Explicit -fno-discard-value-names:
  define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp,
                              ptr %end_time) {
    %expire.i = alloca i64
    %table.i = alloca %struct.poll_wqueues
    %stack_fds = alloca [64 x i32]

The rule for generating human readable LLVM IR (.ll) is only useful as a
debugging feature:

$ make LLVM=1 fs/select.ll

Clang defaults to -fdiscard-value-names to save memory when generating
LLVM IR. For debugging purposes, the improvement in readability at a
cost of more verbose IR is a cost we're happy to pay.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
 scripts/Makefile.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 27be77c0d6d8..d0e4f476dfee 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -140,7 +140,7 @@ $(obj)/%.symtypes : $(src)/%.c FORCE
 # LLVM assembly
 # Generate .ll files from .c
 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
-      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
+      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
 
 $(obj)/%.ll: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_ll_c)

base-commit: 93ed07a23fd08b8613f64cf0a15d7fbdaca010fd
-- 
2.38.0.rc2.412.g84df46c1b4-goog


^ permalink raw reply related	[flat|nested] 7+ messages in thread
* Re: [PATCH] kbuild: add -fno-discard-value-names to cmd_cc_ll_c
  2022-10-07 20:32 [PATCH] kbuild: add -fno-discard-value-names to cmd_cc_ll_c Nick Desaulniers
@ 2022-10-13 19:56 ` Nathan Chancellor
  2022-10-13 20:41   ` Fangrui Song
  0 siblings, 1 reply; 7+ messages in thread
From: Nathan Chancellor @ 2022-10-13 19:56 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Masahiro Yamada, Michal Marek, Tom Rix, linux-kbuild, linux-kernel, llvm

On Fri, Oct 07, 2022 at 01:32:36PM -0700, Nick Desaulniers wrote:
> When debugging LLVM IR, it can be handy for clang to not discard value
> names used for local variables and parameters. Compare the generated IR.
> 
> Implicit Default (-fdiscard-value-names):
>   define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) {
>     %6 = alloca i64
>     %7 = alloca %struct.poll_wqueues
>     %8 = alloca [64 x i32]
> 
> Explicit -fno-discard-value-names:
>   define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp,
>                               ptr %end_time) {
>     %expire.i = alloca i64
>     %table.i = alloca %struct.poll_wqueues
>     %stack_fds = alloca [64 x i32]
> 
> The rule for generating human readable LLVM IR (.ll) is only useful as a
> debugging feature:
> 
> $ make LLVM=1 fs/select.ll
> 
> Clang defaults to -fdiscard-value-names to save memory when generating
> LLVM IR. For debugging purposes, the improvement in readability at a
> cost of more verbose IR is a cost we're happy to pay.
> 
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Thanks for the patch!

Link: https://github.com/ClangBuiltLinux/linux/issues/1467
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  scripts/Makefile.build | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 27be77c0d6d8..d0e4f476dfee 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -140,7 +140,7 @@ $(obj)/%.symtypes : $(src)/%.c FORCE
>  # LLVM assembly
>  # Generate .ll files from .c
>  quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
> -      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
> +      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
>  
>  $(obj)/%.ll: $(src)/%.c FORCE
>  	$(call if_changed_dep,cc_ll_c)
> 
> base-commit: 93ed07a23fd08b8613f64cf0a15d7fbdaca010fd
> -- 
> 2.38.0.rc2.412.g84df46c1b4-goog
> 

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] kbuild: add -fno-discard-value-names to cmd_cc_ll_c
  2022-10-13 19:56 ` Nathan Chancellor
@ 2022-10-13 20:41   ` Fangrui Song
  2022-10-13 20:53     ` Nick Desaulniers
  0 siblings, 1 reply; 7+ messages in thread
From: Fangrui Song @ 2022-10-13 20:41 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: Nick Desaulniers, Masahiro Yamada, Michal Marek, Tom Rix,
	linux-kbuild, linux-kernel, llvm

On 2022-10-13, Nathan Chancellor wrote:
>On Fri, Oct 07, 2022 at 01:32:36PM -0700, Nick Desaulniers wrote:
>> When debugging LLVM IR, it can be handy for clang to not discard value
>> names used for local variables and parameters. Compare the generated IR.
>>
>> Implicit Default (-fdiscard-value-names):
>>   define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) {
>>     %6 = alloca i64
>>     %7 = alloca %struct.poll_wqueues
>>     %8 = alloca [64 x i32]
>>
>> Explicit -fno-discard-value-names:
>>   define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp,
>>                               ptr %end_time) {
>>     %expire.i = alloca i64
>>     %table.i = alloca %struct.poll_wqueues
>>     %stack_fds = alloca [64 x i32]
>>
>> The rule for generating human readable LLVM IR (.ll) is only useful as a
>> debugging feature:
>>
>> $ make LLVM=1 fs/select.ll
>>
>> Clang defaults to -fdiscard-value-names to save memory when generating
>> LLVM IR. For debugging purposes, the improvement in readability at a
>> cost of more verbose IR is a cost we're happy to pay.

A LLVM_ENABLE_ASSEERTIONS=off build of Clang defaults to -fdiscard-value-names.

A LLVM_ENABLE_ASSEERTIONS=on build of Clang defaults to -fno-discard-value-names.

See clang/lib/Driver/ToolChains/Clang.cpp:5030

>> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
>
>Thanks for the patch!
>
>Link: https://github.com/ClangBuiltLinux/linux/issues/1467
>Reviewed-by: Nathan Chancellor <nathan@kernel.org>

Reviewed-by: Fangrui Song <maskray@google.com>

>> ---
>>  scripts/Makefile.build | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
>> index 27be77c0d6d8..d0e4f476dfee 100644
>> --- a/scripts/Makefile.build
>> +++ b/scripts/Makefile.build
>> @@ -140,7 +140,7 @@ $(obj)/%.symtypes : $(src)/%.c FORCE
>>  # LLVM assembly
>>  # Generate .ll files from .c
>>  quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
>> -      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
>> +      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
>>
>>  $(obj)/%.ll: $(src)/%.c FORCE
>>  	$(call if_changed_dep,cc_ll_c)
>>
>> base-commit: 93ed07a23fd08b8613f64cf0a15d7fbdaca010fd
>> --
>> 2.38.0.rc2.412.g84df46c1b4-goog
>>
>

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] kbuild: add -fno-discard-value-names to cmd_cc_ll_c
  2022-10-13 20:41   ` Fangrui Song
@ 2022-10-13 20:53     ` Nick Desaulniers
  2022-10-14 13:30       ` Masahiro Yamada
  0 siblings, 1 reply; 7+ messages in thread
From: Nick Desaulniers @ 2022-10-13 20:53 UTC (permalink / raw)
  To: Fangrui Song
  Cc: Nathan Chancellor, Masahiro Yamada, Michal Marek, Tom Rix,
	linux-kbuild, linux-kernel, llvm

On Thu, Oct 13, 2022 at 1:41 PM Fangrui Song <maskray@google.com> wrote:
>
> On 2022-10-13, Nathan Chancellor wrote:
> >On Fri, Oct 07, 2022 at 01:32:36PM -0700, Nick Desaulniers wrote:
> >> When debugging LLVM IR, it can be handy for clang to not discard value
> >> names used for local variables and parameters. Compare the generated IR.
> >>
> >> Implicit Default (-fdiscard-value-names):
> >>   define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) {
> >>     %6 = alloca i64
> >>     %7 = alloca %struct.poll_wqueues
> >>     %8 = alloca [64 x i32]
> >>
> >> Explicit -fno-discard-value-names:
> >>   define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp,
> >>                               ptr %end_time) {
> >>     %expire.i = alloca i64
> >>     %table.i = alloca %struct.poll_wqueues
> >>     %stack_fds = alloca [64 x i32]
> >>
> >> The rule for generating human readable LLVM IR (.ll) is only useful as a
> >> debugging feature:
> >>
> >> $ make LLVM=1 fs/select.ll
> >>
> >> Clang defaults to -fdiscard-value-names to save memory when generating
> >> LLVM IR. For debugging purposes, the improvement in readability at a
> >> cost of more verbose IR is a cost we're happy to pay.
>
> A LLVM_ENABLE_ASSEERTIONS=off build of Clang defaults to -fdiscard-value-names.
>
> A LLVM_ENABLE_ASSEERTIONS=on build of Clang defaults to -fno-discard-value-names.
>
> See clang/lib/Driver/ToolChains/Clang.cpp:5030

Thanks!

I thought I recalled this; I was literally just rereading through
https://github.com/ClangBuiltLinux/linux/issues/1467#issuecomment-1046071624
again to understand.

That would be useful to include in the commit message, and is more
precise than "Clang defaults to -fdiscard-value-names to save memory
when generating LLVM IR."  Masahiro, would you mind including or
replacing that, or shall I send a v2?

I was surprised to find later in the day that I was running an
assertions-disabled (ie. release) build of clang, which I almost never
do!  Non-llvm-developers are more likely to be using release builds
than assertions-enabled builds of llvm, so this patch still very much
has merit.

>
> >> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> >
> >Thanks for the patch!
> >
> >Link: https://github.com/ClangBuiltLinux/linux/issues/1467
> >Reviewed-by: Nathan Chancellor <nathan@kernel.org>
>
> Reviewed-by: Fangrui Song <maskray@google.com>
>
> >> ---
> >>  scripts/Makefile.build | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> >> index 27be77c0d6d8..d0e4f476dfee 100644
> >> --- a/scripts/Makefile.build
> >> +++ b/scripts/Makefile.build
> >> @@ -140,7 +140,7 @@ $(obj)/%.symtypes : $(src)/%.c FORCE
> >>  # LLVM assembly
> >>  # Generate .ll files from .c
> >>  quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
> >> -      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
> >> +      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
> >>
> >>  $(obj)/%.ll: $(src)/%.c FORCE
> >>      $(call if_changed_dep,cc_ll_c)
> >>
> >> base-commit: 93ed07a23fd08b8613f64cf0a15d7fbdaca010fd
> >> --
> >> 2.38.0.rc2.412.g84df46c1b4-goog
> >>
> >



-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] kbuild: add -fno-discard-value-names to cmd_cc_ll_c
  2022-10-13 20:53     ` Nick Desaulniers
@ 2022-10-14 13:30       ` Masahiro Yamada
  2022-10-14 16:47         ` [PATCH v2] " Nick Desaulniers
  0 siblings, 1 reply; 7+ messages in thread
From: Masahiro Yamada @ 2022-10-14 13:30 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Fangrui Song, Nathan Chancellor, Michal Marek, Tom Rix,
	linux-kbuild, linux-kernel, llvm

On Fri, Oct 14, 2022 at 5:54 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> On Thu, Oct 13, 2022 at 1:41 PM Fangrui Song <maskray@google.com> wrote:
> >
> > On 2022-10-13, Nathan Chancellor wrote:
> > >On Fri, Oct 07, 2022 at 01:32:36PM -0700, Nick Desaulniers wrote:
> > >> When debugging LLVM IR, it can be handy for clang to not discard value
> > >> names used for local variables and parameters. Compare the generated IR.
> > >>
> > >> Implicit Default (-fdiscard-value-names):
> > >>   define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) {
> > >>     %6 = alloca i64
> > >>     %7 = alloca %struct.poll_wqueues
> > >>     %8 = alloca [64 x i32]
> > >>
> > >> Explicit -fno-discard-value-names:
> > >>   define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp,
> > >>                               ptr %end_time) {
> > >>     %expire.i = alloca i64
> > >>     %table.i = alloca %struct.poll_wqueues
> > >>     %stack_fds = alloca [64 x i32]
> > >>
> > >> The rule for generating human readable LLVM IR (.ll) is only useful as a
> > >> debugging feature:
> > >>
> > >> $ make LLVM=1 fs/select.ll
> > >>
> > >> Clang defaults to -fdiscard-value-names to save memory when generating
> > >> LLVM IR. For debugging purposes, the improvement in readability at a
> > >> cost of more verbose IR is a cost we're happy to pay.
> >
> > A LLVM_ENABLE_ASSEERTIONS=off build of Clang defaults to -fdiscard-value-names.
> >
> > A LLVM_ENABLE_ASSEERTIONS=on build of Clang defaults to -fno-discard-value-names.
> >
> > See clang/lib/Driver/ToolChains/Clang.cpp:5030
>
> Thanks!
>
> I thought I recalled this; I was literally just rereading through
> https://github.com/ClangBuiltLinux/linux/issues/1467#issuecomment-1046071624
> again to understand.
>
> That would be useful to include in the commit message, and is more
> precise than "Clang defaults to -fdiscard-value-names to save memory
> when generating LLVM IR."  Masahiro, would you mind including or
> replacing that, or shall I send a v2?




Can you send v2, or provide the entire new commit description?
Thank you.








>
> I was surprised to find later in the day that I was running an
> assertions-disabled (ie. release) build of clang, which I almost never
> do!  Non-llvm-developers are more likely to be using release builds
> than assertions-enabled builds of llvm, so this patch still very much
> has merit.
>
> >
> > >> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > >
> > >Thanks for the patch!
> > >
> > >Link: https://github.com/ClangBuiltLinux/linux/issues/1467
> > >Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> >
> > Reviewed-by: Fangrui Song <maskray@google.com>
> >
> > >> ---
> > >>  scripts/Makefile.build | 2 +-
> > >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > >>
> > >> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> > >> index 27be77c0d6d8..d0e4f476dfee 100644
> > >> --- a/scripts/Makefile.build
> > >> +++ b/scripts/Makefile.build
> > >> @@ -140,7 +140,7 @@ $(obj)/%.symtypes : $(src)/%.c FORCE
> > >>  # LLVM assembly
> > >>  # Generate .ll files from .c
> > >>  quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
> > >> -      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
> > >> +      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
> > >>
> > >>  $(obj)/%.ll: $(src)/%.c FORCE
> > >>      $(call if_changed_dep,cc_ll_c)
> > >>
> > >> base-commit: 93ed07a23fd08b8613f64cf0a15d7fbdaca010fd
> > >> --
> > >> 2.38.0.rc2.412.g84df46c1b4-goog
> > >>
> > >
>
>
>
> --
> Thanks,
> ~Nick Desaulniers



-- 
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 7+ messages in thread
* [PATCH v2] kbuild: add -fno-discard-value-names to cmd_cc_ll_c
  2022-10-14 13:30       ` Masahiro Yamada
@ 2022-10-14 16:47         ` Nick Desaulniers
  2022-10-14 16:53           ` [PATCH v3] " Nick Desaulniers
  0 siblings, 1 reply; 7+ messages in thread
From: Nick Desaulniers @ 2022-10-14 16:47 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Michal Marek, Nathan Chancellor, Tom Rix, linux-kbuild,
	linux-kernel, llvm, Nick Desaulniers, Fangrui Song

When debugging LLVM IR, it can be handy for clang to not discard value
names used for local variables and parameters. Compare the generated IR.

-fdiscard-value-names:
  define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) {
    %6 = alloca i64
    %7 = alloca %struct.poll_wqueues
    %8 = alloca [64 x i32]

-fno-discard-value-names:
  define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp,
                              ptr %end_time) {
    %expire.i = alloca i64
    %table.i = alloca %struct.poll_wqueues
    %stack_fds = alloca [64 x i32]

The rule for generating human readable LLVM IR (.ll) is only useful as a
debugging feature:

$ make LLVM=1 fs/select.ll

As Fangrui notes:
  A LLVM_ENABLE_ASSERTIONS=off build of Clang defaults to
  -fdiscard-value-names.

  A LLVM_ENABLE_ASSERTIONS=on build of Clang defaults to
  -fno-discard-value-names.

Explicitly enable -fdiscard-value-names so that the IR always contains
value names regardless of whether assertions were enabled or not.
Assertions generally are not enabled in releases of clang packaged by
distributions.

Link: https://github.com/ClangBuiltLinux/linux/issues/1467
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes v1 -> v2:
* Only update commit message:
  * Pick up Nathan & Fangrui's RB tags.
  * Add link (I forgot I filed a bug about this a while ago!).
  * Add note from Fangrui.
  * Add final paragraph.


 scripts/Makefile.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 22adbf89cb31..41f3602fc8de 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -140,7 +140,7 @@ $(obj)/%.symtypes : $(src)/%.c FORCE
 # LLVM assembly
 # Generate .ll files from .c
 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
-      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
+      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
 
 $(obj)/%.ll: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_ll_c)
-- 
2.38.0.413.g74048e4d9e-goog


^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH v3] kbuild: add -fno-discard-value-names to cmd_cc_ll_c
  2022-10-14 16:47         ` [PATCH v2] " Nick Desaulniers
@ 2022-10-14 16:53           ` Nick Desaulniers
  0 siblings, 0 replies; 7+ messages in thread
From: Nick Desaulniers @ 2022-10-14 16:53 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Michal Marek, Nathan Chancellor, Tom Rix, linux-kbuild,
	linux-kernel, llvm, Nick Desaulniers, Fangrui Song

When debugging LLVM IR, it can be handy for clang to not discard value
names used for local variables and parameters. Compare the generated IR.

-fdiscard-value-names:
  define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) {
    %6 = alloca i64
    %7 = alloca %struct.poll_wqueues
    %8 = alloca [64 x i32]

-fno-discard-value-names:
  define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp,
                              ptr %end_time) {
    %expire.i = alloca i64
    %table.i = alloca %struct.poll_wqueues
    %stack_fds = alloca [64 x i32]

The rule for generating human readable LLVM IR (.ll) is only useful as a
debugging feature:

$ make LLVM=1 fs/select.ll

As Fangrui notes:
  A LLVM_ENABLE_ASSERTIONS=off build of Clang defaults to
  -fdiscard-value-names.

  A LLVM_ENABLE_ASSERTIONS=on build of Clang defaults to
  -fno-discard-value-names.

Explicitly enable -fno-discard-value-names so that the IR always contains
value names regardless of whether assertions were enabled or not.
Assertions generally are not enabled in releases of clang packaged by
distributions.

Link: https://github.com/ClangBuiltLinux/linux/issues/1467
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes v2 -> v3:
* Fix typo in commit message
  "enable -fdiscard-value-names" -> "enable -fno-discard-value-names"

Changes v1 -> v2:
* Only update commit message:
  * Pick up Nathan & Fangrui's RB tags.
  * Add link (I forgot I filed a bug about this a while ago!).
  * Add note from Fangrui.
  * Add final paragraph.
 scripts/Makefile.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 22adbf89cb31..41f3602fc8de 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -140,7 +140,7 @@ $(obj)/%.symtypes : $(src)/%.c FORCE
 # LLVM assembly
 # Generate .ll files from .c
 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
-      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
+      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
 
 $(obj)/%.ll: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_ll_c)
-- 
2.38.0.413.g74048e4d9e-goog


^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-10-14 16:53 UTC | newest]

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2022-10-07 20:32 [PATCH] kbuild: add -fno-discard-value-names to cmd_cc_ll_c Nick Desaulniers
2022-10-13 19:56 ` Nathan Chancellor
2022-10-13 20:41   ` Fangrui Song
2022-10-13 20:53     ` Nick Desaulniers
2022-10-14 13:30       ` Masahiro Yamada
2022-10-14 16:47         ` [PATCH v2] " Nick Desaulniers
2022-10-14 16:53           ` [PATCH v3] " Nick Desaulniers

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