无法使用 arm-none-eabi-as 组装由 llc 生成的 .s 文件？

Question

My English skill is poor because I'm not a native English speaker.

I compiled a bitcode using llc.exe and get a .s file (test.s). The command that I used to create test.s is as below.

llc -march=thumb -mattr=thumb2 -mcpu=cortex-m3 main.bc -o test.s

Yes, my target board is cortex-m3 (stm32l series) and I created makefile as below to create .bin file.

bin: test.s
    @echo "Running target all"
    arm-none-eabi-as c:/backend/files/test.s -o c:/backend/files/test.o
    arm-none-eabi-ld -Ttext=0x08000000 c:/backend/files/test.o -o c:/backend/files/test.elf
    arm-none-eabi-objdump -D c:/backend/files/test.elf
    arm-none-eabi-objcopy c:/backend/files/test.elf -O binary c:/backend/files/test.bin

clean:
    @echo "Running target clean"
    rm -f *.o
    rm -f *.elf
    rm -f *.bin

makefile is simple. It's goal is to create test.bin from test.s file.

test.s file is as below. I created test.s file

    .text
    .syntax unified
    .file   "main.bc"
    .def     main;
    .scl    2;
    .type   32;
    .endef
    .globl  main                    ; -- Begin function main
    .p2align    1
    .code16                         ; @main
    .thumb_func
main:
; %bb.0:
    sub sp, #8
    movs    r0, #10
    movs    r1, #20
    cmp r0, #21
    str r0, [sp, #4]
    str r1, [sp]
    blo ($MBB0_2)
; %bb.1:
    ldr r0, [sp, #4]
    adds    r0, #1
    str r0, [sp, #4]
$MBB0_2:
    add sp, #8
    bx  lr
                                        ; -- End function

EveryThing went smoothly until here. Here I executed make.exe to create test.bin but I got a error as below.

I don't know if the .s file that generated by llc.exe is not format of cortex-m3.

Could someone help me? I want to know what cause of problem is.

Thanks for reading.

------------------------------- update -----------------------------------

Original code is as below. The code was write just test purpose.

void main()
{
    int a = 10;
    int b = 20;

    if ( a > b) a ++;
}

The bitcode is as below. The bitcode was generated manually.

define void @main()
{
%1 = alloca i32, align 4
%2 = alloca i32, align 4
store i32 10, i32* %1, align 4
store i32 20, i32* %2, align 4
%3 = load i32, i32* %1, align 4
%4 = load i32, i32* %2, align 4
%5 = icmp ugt i32 %3, %4
br i1 %5, label %6, label %9

;%6
%7 = load i32, i32* %1, align 4
%8 = add nsw i32 %7, 1
store i32 %8, i32* %1, align 4
br label %9

;%9
ret void
}

Answer 1

I solved this problem thanks for Frant's comment.

I updated bitcode file as below.

define void @main() #0
{
%1 = alloca i32, align 4
%2 = alloca i32, align 4
store i32 10, i32* %1, align 4
store i32 20, i32* %2, align 4
%3 = load i32, i32* %1, align 4
%4 = load i32, i32* %2, align 4
%5 = icmp ugt i32 %3, %4
br i1 %5, label %6, label %9

;%6
%7 = load i32, i32* %1, align 4
%8 = add nsw i32 %7, 1
store i32 %8, i32* %1, align 4
br label %9

;%9
ret void
}

attributes #0 =
{
norecurse nounwind readnone
"stack-protector-buffer-size"="8"
}

And I updated llc command to as below.

llc -mtriple=arm-none-eabi -march=thumb -mattr=thumb2 -mcpu=cortex-m3 main.bc -o test.s

The result .s file is generated correctly.

Thanks for your interest in my problem.