* [PATCH] RISC-V: jal cannot refer to a default visibility symbol for shared object.
@ 2021-11-29 12:48 Nelson Chu
2021-12-06 9:07 ` Kito Cheng
0 siblings, 1 reply; 2+ messages in thread
From: Nelson Chu @ 2021-11-29 12:48 UTC (permalink / raw)
To: gcc-patches, jim.wilson.gcc, kito.cheng, maskray; +Cc: nelson.chu
This is the original binutils bugzilla report,
https://sourceware.org/bugzilla/show_bug.cgi?id=28509
And this is the first version of the proposed binutils patch,
https://sourceware.org/pipermail/binutils/2021-November/118398.html
After applying the binutils patch, I get the the unexpected error when
building libgcc,
/scratch/nelsonc/riscv-gnu-toolchain/riscv-gcc/libgcc/config/riscv/div.S:42:
/scratch/nelsonc/build-upstream/rv64gc-linux/build-install/riscv64-unknown-linux-gnu/bin/ld: relocation R_RISCV_JAL against `__udivdi3' which may bind externally can not be used when making a shared object; recompile with -fPIC
Therefore, this patch add an extra hidden alias symbol for __udivdi3, and
then use HIDDEN_JUMPTARGET to target a non-preemptible symbol instead.
The solution is similar to glibc as follows,
https://sourceware.org/git/?p=glibc.git;a=commit;h=68389203832ab39dd0dbaabbc4059e7fff51c29b
libgcc/ChangeLog:
* config/riscv/div.S: Add the hidden alias symbol for __udivdi3, and
then use HIDDEN_JUMPTARGET to target it since it is non-preemptible.
* config/riscv/riscv-asm.h: Added new macros HIDDEN_JUMPTARGET and
HIDDEN_DEF.
---
libgcc/config/riscv/div.S | 15 ++++++++-------
libgcc/config/riscv/riscv-asm.h | 6 ++++++
2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/libgcc/config/riscv/div.S b/libgcc/config/riscv/div.S
index c9bd787..723c3b8 100644
--- a/libgcc/config/riscv/div.S
+++ b/libgcc/config/riscv/div.S
@@ -40,7 +40,7 @@ FUNC_BEGIN (__udivsi3)
sll a0, a0, 32
sll a1, a1, 32
move t0, ra
- jal __udivdi3
+ jal HIDDEN_JUMPTARGET(__udivdi3)
sext.w a0, a0
jr t0
FUNC_END (__udivsi3)
@@ -52,7 +52,7 @@ FUNC_BEGIN (__umodsi3)
srl a0, a0, 32
srl a1, a1, 32
move t0, ra
- jal __udivdi3
+ jal HIDDEN_JUMPTARGET(__udivdi3)
sext.w a0, a1
jr t0
FUNC_END (__umodsi3)
@@ -95,11 +95,12 @@ FUNC_BEGIN (__udivdi3)
.L5:
ret
FUNC_END (__udivdi3)
+HIDDEN_DEF (__udivdi3)
FUNC_BEGIN (__umoddi3)
/* Call __udivdi3(a0, a1), then return the remainder, which is in a1. */
move t0, ra
- jal __udivdi3
+ jal HIDDEN_JUMPTARGET(__udivdi3)
move a0, a1
jr t0
FUNC_END (__umoddi3)
@@ -111,12 +112,12 @@ FUNC_END (__umoddi3)
bgtz a1, .L12 /* Compute __udivdi3(-a0, a1), then negate the result. */
neg a1, a1
- j __udivdi3 /* Compute __udivdi3(-a0, -a1). */
+ j HIDDEN_JUMPTARGET(__udivdi3) /* Compute __udivdi3(-a0, -a1). */
.L11: /* Compute __udivdi3(a0, -a1), then negate the result. */
neg a1, a1
.L12:
move t0, ra
- jal __udivdi3
+ jal HIDDEN_JUMPTARGET(__udivdi3)
neg a0, a0
jr t0
FUNC_END (__divdi3)
@@ -126,7 +127,7 @@ FUNC_BEGIN (__moddi3)
bltz a1, .L31
bltz a0, .L32
.L30:
- jal __udivdi3 /* The dividend is not negative. */
+ jal HIDDEN_JUMPTARGET(__udivdi3) /* The dividend is not negative. */
move a0, a1
jr t0
.L31:
@@ -134,7 +135,7 @@ FUNC_BEGIN (__moddi3)
bgez a0, .L30
.L32:
neg a0, a0
- jal __udivdi3 /* The dividend is hella negative. */
+ jal HIDDEN_JUMPTARGET(__udivdi3) /* The dividend is hella negative. */
neg a0, a1
jr t0
FUNC_END (__moddi3)
diff --git a/libgcc/config/riscv/riscv-asm.h b/libgcc/config/riscv/riscv-asm.h
index 8550707..96dd85b 100644
--- a/libgcc/config/riscv/riscv-asm.h
+++ b/libgcc/config/riscv/riscv-asm.h
@@ -33,3 +33,9 @@ X:
#define FUNC_ALIAS(X,Y) \
.globl X; \
X = Y
+
+#define CONCAT1(a, b) CONCAT2(a, b)
+#define CONCAT2(a, b) a ## b
+#define HIDDEN_JUMPTARGET(X) CONCAT1(__hidden_, X)
+#define HIDDEN_DEF(X) FUNC_ALIAS(HIDDEN_JUMPTARGET(X), X); \
+ .hidden HIDDEN_JUMPTARGET(X)
--
2.7.4
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] RISC-V: jal cannot refer to a default visibility symbol for shared object.
2021-11-29 12:48 [PATCH] RISC-V: jal cannot refer to a default visibility symbol for shared object Nelson Chu
@ 2021-12-06 9:07 ` Kito Cheng
0 siblings, 0 replies; 2+ messages in thread
From: Kito Cheng @ 2021-12-06 9:07 UTC (permalink / raw)
To: Nelson Chu; +Cc: GCC Patches, jim.wilson.gcc, Kito Cheng, maskray
Committed, thanks :)
On Mon, Nov 29, 2021 at 8:48 PM Nelson Chu <nelson.chu@sifive.com> wrote:
>
> This is the original binutils bugzilla report,
> https://sourceware.org/bugzilla/show_bug.cgi?id=28509
>
> And this is the first version of the proposed binutils patch,
> https://sourceware.org/pipermail/binutils/2021-November/118398.html
>
> After applying the binutils patch, I get the the unexpected error when
> building libgcc,
>
> /scratch/nelsonc/riscv-gnu-toolchain/riscv-gcc/libgcc/config/riscv/div.S:42:
> /scratch/nelsonc/build-upstream/rv64gc-linux/build-install/riscv64-unknown-linux-gnu/bin/ld: relocation R_RISCV_JAL against `__udivdi3' which may bind externally can not be used when making a shared object; recompile with -fPIC
>
> Therefore, this patch add an extra hidden alias symbol for __udivdi3, and
> then use HIDDEN_JUMPTARGET to target a non-preemptible symbol instead.
> The solution is similar to glibc as follows,
> https://sourceware.org/git/?p=glibc.git;a=commit;h=68389203832ab39dd0dbaabbc4059e7fff51c29b
>
> libgcc/ChangeLog:
>
> * config/riscv/div.S: Add the hidden alias symbol for __udivdi3, and
> then use HIDDEN_JUMPTARGET to target it since it is non-preemptible.
> * config/riscv/riscv-asm.h: Added new macros HIDDEN_JUMPTARGET and
> HIDDEN_DEF.
> ---
> libgcc/config/riscv/div.S | 15 ++++++++-------
> libgcc/config/riscv/riscv-asm.h | 6 ++++++
> 2 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/libgcc/config/riscv/div.S b/libgcc/config/riscv/div.S
> index c9bd787..723c3b8 100644
> --- a/libgcc/config/riscv/div.S
> +++ b/libgcc/config/riscv/div.S
> @@ -40,7 +40,7 @@ FUNC_BEGIN (__udivsi3)
> sll a0, a0, 32
> sll a1, a1, 32
> move t0, ra
> - jal __udivdi3
> + jal HIDDEN_JUMPTARGET(__udivdi3)
> sext.w a0, a0
> jr t0
> FUNC_END (__udivsi3)
> @@ -52,7 +52,7 @@ FUNC_BEGIN (__umodsi3)
> srl a0, a0, 32
> srl a1, a1, 32
> move t0, ra
> - jal __udivdi3
> + jal HIDDEN_JUMPTARGET(__udivdi3)
> sext.w a0, a1
> jr t0
> FUNC_END (__umodsi3)
> @@ -95,11 +95,12 @@ FUNC_BEGIN (__udivdi3)
> .L5:
> ret
> FUNC_END (__udivdi3)
> +HIDDEN_DEF (__udivdi3)
>
> FUNC_BEGIN (__umoddi3)
> /* Call __udivdi3(a0, a1), then return the remainder, which is in a1. */
> move t0, ra
> - jal __udivdi3
> + jal HIDDEN_JUMPTARGET(__udivdi3)
> move a0, a1
> jr t0
> FUNC_END (__umoddi3)
> @@ -111,12 +112,12 @@ FUNC_END (__umoddi3)
> bgtz a1, .L12 /* Compute __udivdi3(-a0, a1), then negate the result. */
>
> neg a1, a1
> - j __udivdi3 /* Compute __udivdi3(-a0, -a1). */
> + j HIDDEN_JUMPTARGET(__udivdi3) /* Compute __udivdi3(-a0, -a1). */
> .L11: /* Compute __udivdi3(a0, -a1), then negate the result. */
> neg a1, a1
> .L12:
> move t0, ra
> - jal __udivdi3
> + jal HIDDEN_JUMPTARGET(__udivdi3)
> neg a0, a0
> jr t0
> FUNC_END (__divdi3)
> @@ -126,7 +127,7 @@ FUNC_BEGIN (__moddi3)
> bltz a1, .L31
> bltz a0, .L32
> .L30:
> - jal __udivdi3 /* The dividend is not negative. */
> + jal HIDDEN_JUMPTARGET(__udivdi3) /* The dividend is not negative. */
> move a0, a1
> jr t0
> .L31:
> @@ -134,7 +135,7 @@ FUNC_BEGIN (__moddi3)
> bgez a0, .L30
> .L32:
> neg a0, a0
> - jal __udivdi3 /* The dividend is hella negative. */
> + jal HIDDEN_JUMPTARGET(__udivdi3) /* The dividend is hella negative. */
> neg a0, a1
> jr t0
> FUNC_END (__moddi3)
> diff --git a/libgcc/config/riscv/riscv-asm.h b/libgcc/config/riscv/riscv-asm.h
> index 8550707..96dd85b 100644
> --- a/libgcc/config/riscv/riscv-asm.h
> +++ b/libgcc/config/riscv/riscv-asm.h
> @@ -33,3 +33,9 @@ X:
> #define FUNC_ALIAS(X,Y) \
> .globl X; \
> X = Y
> +
> +#define CONCAT1(a, b) CONCAT2(a, b)
> +#define CONCAT2(a, b) a ## b
> +#define HIDDEN_JUMPTARGET(X) CONCAT1(__hidden_, X)
> +#define HIDDEN_DEF(X) FUNC_ALIAS(HIDDEN_JUMPTARGET(X), X); \
> + .hidden HIDDEN_JUMPTARGET(X)
> --
> 2.7.4
>
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