[PATCH 1/2] smartweb: Enable LTO

[PATCH 1/2] smartweb: Enable LTO

[Tom Rini]

In order to prepare for slight size growth due to reworking linker list
support, enable LTO here to save more space again.

Signed-off-by: Tom Rini <trini@konsulko.com>
---
Cc: Heiko Schocher <hs@denx.de>
---
 configs/smartweb_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configs/smartweb_defconfig b/configs/smartweb_defconfig
index 4cbdab0b37d8..836e0c002dee 100644
--- a/configs/smartweb_defconfig
+++ b/configs/smartweb_defconfig
@@ -24,6 +24,7 @@ CONFIG_SPL_SYS_MALLOC_F_LEN=0x400
 CONFIG_SPL=y
 CONFIG_ENV_OFFSET_REDUND=0x180000
 CONFIG_SYS_LOAD_ADDR=0x22000000
+CONFIG_LTO=y
 CONFIG_FIT=y
 CONFIG_NAND_BOOT=y
 CONFIG_BOOTDELAY=3
-- 
2.34.1

[PATCH 2/2] linker_lists: Rework start/end macros to not rely on undefined behavior

[Tom Rini]

Per the GCC bug listed below, the way we do linker lists is relying on
undefined behavior that seems to work in gcc, but doesn't always work in
clang. Andrew suggests rewriting our start/end macros in a different way
(as implemented here, from what he said in comment 1) to avoid these
problems.

Reported-by: AdityaK <appujee@google.com>
Suggested-by: Andrew Pinski <pinskia@gcc.gnu.org>
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108915
Signed-off-by: Tom Rini <trini@konsulko.com>
---
Andrew, please feel free to reply with any further tags you want here, I
wasn't exactly sure of the best way to attribute this to you.  Thanks!
---
 include/linker_lists.h | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/linker_lists.h b/include/linker_lists.h
index d3da9d44e853..f9a2ee0c762a 100644
--- a/include/linker_lists.h
+++ b/include/linker_lists.h
@@ -127,7 +127,9 @@
 	static char start[0] __aligned(CONFIG_LINKER_LIST_ALIGN)	\
 		__attribute__((unused))					\
 		__section("__u_boot_list_2_"#_list"_1");			\
-	(_type *)&start;						\
+	_type * tmp = (_type *)&start;					\
+	asm("":"+r"(tmp));						\
+	tmp;								\
 })
 
 /**
@@ -153,7 +155,9 @@
 ({									\
 	static char end[0] __aligned(4) __attribute__((unused))		\
 		__section("__u_boot_list_2_"#_list"_3");			\
-	(_type *)&end;							\
+	_type * tmp = (_type *)&end;					\
+	asm("":"+r"(tmp));						\
+	tmp;								\
 })
 /**
  * ll_entry_count() - Return the number of elements in linker-generated array
@@ -247,7 +251,9 @@
 ({									\
 	static char start[0] __aligned(4) __attribute__((unused))	\
 		__section("__u_boot_list_1");				\
-	(_type *)&start;						\
+	_type * tmp = (_type *)&start;					\
+	asm("":"+r"(tmp));						\
+	tmp;								\
 })
 
 /**
@@ -270,7 +276,9 @@
 ({									\
 	static char end[0] __aligned(4) __attribute__((unused))		\
 		__section("__u_boot_list_3");				\
-	(_type *)&end;							\
+	_type * tmp = (_type *)&end;					\
+	asm("":"+r"(tmp));						\
+	tmp;								\
 })
 
 #endif /* __ASSEMBLY__ */
-- 
2.34.1

Re: [PATCH 1/2] smartweb: Enable LTO

[Heiko Schocher]

Hello Tom,

On 28.03.23 20:54, Tom Rini wrote:
> In order to prepare for slight size growth due to reworking linker list
> support, enable LTO here to save more space again.
> 
> Signed-off-by: Tom Rini <trini@konsulko.com>
> ---
> Cc: Heiko Schocher <hs@denx.de>
> ---
>  configs/smartweb_defconfig | 1 +
>  1 file changed, 1 insertion(+)

Reviewed-by: Heiko Schocher <hs@denx.de>

bye,
Heiko
-- 
DENX Software Engineering GmbH,      Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-52   Fax: +49-8142-66989-80   Email: hs@denx.de

Re: [PATCH 2/2] linker_lists: Rework start/end macros to not rely on undefined behavior

[Simon Glass]

On Wed, 29 Mar 2023 at 07:55, Tom Rini <trini@konsulko.com> wrote:
>
> Per the GCC bug listed below, the way we do linker lists is relying on
> undefined behavior that seems to work in gcc, but doesn't always work in
> clang. Andrew suggests rewriting our start/end macros in a different way
> (as implemented here, from what he said in comment 1) to avoid these
> problems.
>
> Reported-by: AdityaK <appujee@google.com>
> Suggested-by: Andrew Pinski <pinskia@gcc.gnu.org>
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108915
> Signed-off-by: Tom Rini <trini@konsulko.com>
> ---
> Andrew, please feel free to reply with any further tags you want here, I
> wasn't exactly sure of the best way to attribute this to you.  Thanks!
> ---
>  include/linker_lists.h | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>

Reviewed-by: Simon Glass <sjg@chromium.org>

Re: [PATCH 2/2] linker_lists: Rework start/end macros to not rely on undefined behavior

[Andrew Pinski]

On Tue, Mar 28, 2023 at 11:54 AM Tom Rini <trini@konsulko.com> wrote:
>
> Per the GCC bug listed below, the way we do linker lists is relying on
> undefined behavior that seems to work in gcc, but doesn't always work in
> clang. Andrew suggests rewriting our start/end macros in a different way
> (as implemented here, from what he said in comment 1) to avoid these
> problems.
>
> Reported-by: AdityaK <appujee@google.com>
> Suggested-by: Andrew Pinski <pinskia@gcc.gnu.org>

Suggested-by: Andrew Pinski <apinski@marvell.com>

Other than that it looks good.
Reviewed-by: Andrew Pinski <apinski@marvell.com>

Thanks,
Andrew Pinski

> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108915
> Signed-off-by: Tom Rini <trini@konsulko.com>
> ---
> Andrew, please feel free to reply with any further tags you want here, I
> wasn't exactly sure of the best way to attribute this to you.  Thanks!
> ---
>  include/linker_lists.h | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/include/linker_lists.h b/include/linker_lists.h
> index d3da9d44e853..f9a2ee0c762a 100644
> --- a/include/linker_lists.h
> +++ b/include/linker_lists.h
> @@ -127,7 +127,9 @@
>         static char start[0] __aligned(CONFIG_LINKER_LIST_ALIGN)        \
>                 __attribute__((unused))                                 \
>                 __section("__u_boot_list_2_"#_list"_1");                        \
> -       (_type *)&start;                                                \
> +       _type * tmp = (_type *)&start;                                  \
> +       asm("":"+r"(tmp));                                              \
> +       tmp;                                                            \
>  })
>
>  /**
> @@ -153,7 +155,9 @@
>  ({                                                                     \
>         static char end[0] __aligned(4) __attribute__((unused))         \
>                 __section("__u_boot_list_2_"#_list"_3");                        \
> -       (_type *)&end;                                                  \
> +       _type * tmp = (_type *)&end;                                    \
> +       asm("":"+r"(tmp));                                              \
> +       tmp;                                                            \
>  })
>  /**
>   * ll_entry_count() - Return the number of elements in linker-generated array
> @@ -247,7 +251,9 @@
>  ({                                                                     \
>         static char start[0] __aligned(4) __attribute__((unused))       \
>                 __section("__u_boot_list_1");                           \
> -       (_type *)&start;                                                \
> +       _type * tmp = (_type *)&start;                                  \
> +       asm("":"+r"(tmp));                                              \
> +       tmp;                                                            \
>  })
>
>  /**
> @@ -270,7 +276,9 @@
>  ({                                                                     \
>         static char end[0] __aligned(4) __attribute__((unused))         \
>                 __section("__u_boot_list_3");                           \
> -       (_type *)&end;                                                  \
> +       _type * tmp = (_type *)&end;                                    \
> +       asm("":"+r"(tmp));                                              \
> +       tmp;                                                            \
>  })
>
>  #endif /* __ASSEMBLY__ */
> --
> 2.34.1
>

Re: [PATCH 1/2] smartweb: Enable LTO

[Tom Rini]

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On Tue, Mar 28, 2023 at 02:54:50PM -0400, Tom Rini wrote:

> In order to prepare for slight size growth due to reworking linker list
> support, enable LTO here to save more space again.
> 
> Signed-off-by: Tom Rini <trini@konsulko.com>
> Reviewed-by: Heiko Schocher <hs@denx.de>

Applied to u-boot/master, thanks!

-- 
Tom

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Re: [PATCH 2/2] linker_lists: Rework start/end macros to not rely on undefined behavior

[Tom Rini]

[-- Attachment #1: Type: text/plain, Size: 731 bytes --]

On Tue, Mar 28, 2023 at 02:54:51PM -0400, Tom Rini wrote:

> Per the GCC bug listed below, the way we do linker lists is relying on
> undefined behavior that seems to work in gcc, but doesn't always work in
> clang. Andrew suggests rewriting our start/end macros in a different way
> (as implemented here, from what he said in comment 1) to avoid these
> problems.
> 
> Reported-by: AdityaK <appujee@google.com>
> Suggested-by: Andrew Pinski <apinski@marvell.com>
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108915
> Signed-off-by: Tom Rini <trini@konsulko.com>
> Reviewed-by: Simon Glass <sjg@chromium.org>
> Reviewed-by: Andrew Pinski <apinski@marvell.com>

Applied to u-boot/master, thanks!

-- 
Tom

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