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GNU toolchain for RISC-V, including GCC
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Code doesn't compile with riscv32-unknown-elf-ld #1527

Closed RRArinc closed 2 months ago

RRArinc commented 2 months ago

Hi, I have sample code which uses library.

I have linker script and Make file. When compiled with riscv32-unknown-elf-gcc code compiles. But when compiled with riscv32-unknown-elf-ld ends up with error

riscv32-unknown-elf-ld: /home/rr/rv32gcc-toolchain/riscv32-unknown-elf/lib/rv32i/ilp32//libm.a(libm_a-s_round.o): in function round': s_round.c:(.text.round+0xb8): undefined reference to__adddf3' make: *** [Makefile:40: bin/output] Error 1

Here riscv32-unknown-elf-ld is provided with libm.a reference to link, but still it fails.

source file is

include

void operation(void) { double num = 110.00; double result = 0.0;

result = round(num);

}

Thanks

TommyMurphyTM1234 commented 2 months ago

Where did you get or how did you configure and build the toolchain that you're using? What is the riscv32-unknown-elf-gcc command line that you're using to compile the code above?

I grabbed the latest RV32 bare-metal toolchain and compiled and linked a version of the code above without any issues:

wget https://github.com/riscv-collab/riscv-gnu-toolchain/releases/download/2024.08.06/riscv32-elf-ubuntu-22.04-gcc-nightly-2024.08.06-nightly.tar.gz
tar xzvf riscv32-elf-ubuntu-22.04-gcc-nightly-2024.08.06-nightly.tar.gz

cd riscv/bin
vi test.c

# test.c
#include <math.h>
int main()
{
double num = 110.00;
double result = 0.0;

result = round(num);
}

./riscv32-unknown-elf-gcc test.c -lm
file a.out
a.out: ELF 32-bit LSB executable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), statically linked, not stripped

./riscv32-unknown-elf-objdump -dS a.out 

...

00010144 <main>:
   10144:       1101                    addi    sp,sp,-32
   10146:       ce06                    sw      ra,28(sp)
   10148:       cc22                    sw      s0,24(sp)
   1014a:       1000                    addi    s0,sp,32
   1014c:       67c5                    lui     a5,0x11
   1014e:       6887b787                fld     fa5,1672(a5) # 11688 <__errno+0xa>
   10152:       fef43427                fsd     fa5,-24(s0)
   10156:       d20007d3                fcvt.d.w        fa5,zero
   1015a:       fef43027                fsd     fa5,-32(s0)
   1015e:       fe843507                fld     fa0,-24(s0)
   10162:       2809                    jal     10174 <round>
   10164:       fea43027                fsd     fa0,-32(s0)
   10168:       4781                    li      a5,0
   1016a:       853e                    mv      a0,a5
   1016c:       40f2                    lw      ra,28(sp)
   1016e:       4462                    lw      s0,24(sp)
   10170:       6105                    addi    sp,sp,32
   10172:       8082                    ret

...
RRArinc commented 2 months ago

Hi, Yeah u r right i am able compile the code using riscv32-unknown-elf-gcc.

My question I have linker script and Make file. When compiled with riscv32-unknown-elf-gcc code compiles.

But if i use riscv32-unknow-elf-ld to link the linker script (*.ld) and starup.S file. I ran into below error

riscv32-unknown-elf-ld: /home/rr/rv32gcc-toolchain/riscv32-unknown-elf/lib/rv32i/ilp32//libm.a(libm_a-s_round.o): in function round': s_round.c:(.text.round+0xb8): undefined reference to __adddf3' make: *** [Makefile:40: bin/output] Error 1

It appears to be something softfloat issue it says in function s_round.c undefined reference to __addf3

I also check which libm.s is used by riscv32-unknown-elf-gcc and provided the same lib path to riscv32-unknown-elf-ld, and got the above error.

So question is it compiles well with riscv32-unknown-elf-gcc but fails with riscv32-unknown-elf-ld.

what could be the root cause.

TommyMurphyTM1234 commented 2 months ago

what could be the root cause.

Impossible to say when you don't provide the reproducible test case and clear instructions on how to reproduce it.

And vague/unclear statements like this don't really help to clarify matters:

It appears to be something softfloat issue it says in function s_round.c undefined reference to __addf3

RRArinc commented 2 months ago

Hi, I was able to figure out the issue.

The linker was not able find the right soft-float libm.a

The path above was misleading in Makefile. After updating the absolute path in Makefile it started compiling the program.

Thank you very much.