[LLVMdev] llc generated assembly does not work with gcc 3.4.4

herz
2010-01-27T09:32:11Z

The ll file:

; ModuleID = 't.bc'
target datalayout
"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f80:128:128-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
target triple = "i686-pc-win32"

@.str = private constant [13 x i8] c"hello world\0A\00" ; <[13 x
i8]*>
[#uses=1]

define i32 @main(i32 %argc, i8** %argv) nounwind {
entry:
  %retval = alloca i32                            ; <i32*> [#uses=2]
  %argc.addr = alloca i32                         ; <i32*> [#uses=1]
  %argv.addr = alloca i8**                        ; <i8***> [#uses=1]
  store i32 0, i32* %retval
  store i32 %argc, i32* %argc.addr
  store i8** %argv, i8*** %argv.addr
  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([13 x
i8]* @.str, i32 0, i32 0)) ; <i32> [#uses=0]
  %0 = load i32* %retval                          ; <i32> [#uses=1]
  ret i32 %0
}

declare i32 @printf(i8*, ...)

the llc command line is simply:  llc t.bc (where t.bc is the file used
to generate the ll file shown, of course)

llc --version gives:

Low Level Virtual Machine (http://llvm.org/):
  LLVM (win32 vc8.0) version 2.600000e+000
  DEBUG build.
  Built Dec  3 2009 (01:18:42).

  Registered Targets:
    amdil  - ATI graphics cards
    x86    - 32-bit X86: Pentium-Pro and above
    x86-64 - 64-bit X86: EM64T and AMD64


I've read in the docu (which appears to be somewhat out of date) that
one cannot generate binaries on win32 systems.
The thing I don't understand is why I cannot generate assembly that is
compatible with gcc (albait the cygwin version of gcc, but
certainly cygwin gcc reads the same mnemonics as the unix version??).
I've tryed several llc switches to produce compatible output but failed.

Alex

Chris Lattner schrieb:
>
> On Jan 26, 2010, at 6:31 AM, herz wrote:
>
>> Hi,
>>
>> I've generated a .bc file for a simple program using the clang
front
>> end, the human readable output of llvm-dis looks good.
>> Running llc on the bc file generates an assembly file (.s using either
>> att or intel syntax).
>> Now, when I try to generate an executable with gcc (3.4.4 cygwin) I get
>> lot's of errors:
>
> What commands are you passing to llc?  Also, please attach the .ll
> file you're using.
>
> -Chris
>
>>
>> $ gcc t.S
>> t.S: Assembler messages:
>> t.S:4: Error: no such instruction: `align 16'
>> t.S:6: Error: invalid character '@' in mnemonic
>> t.S:7: Error: no such instruction: `bb'
>> t.S:20: Error: invalid character '@' in mnemonic
>> t.S:22: Error: no such instruction: `db "hello
world\n\000"'
>>
>> here is the assembly file (t.s):
>>
>>    .text
>>    ALIGN    16
>>    .globl    _main
>> _main:                                                      ; @main
>> ; BB#0:                                                     ; %entry
>>    subl    $20, %esp
>>    movl    24(%esp), %eax
>>    movl    $0, 16(%esp)
>>    movl    $($_.str), (%esp)
>>    movl    %eax, 12(%esp)
>>    movl    28(%esp), %eax
>>    movl    %eax, 8(%esp)
>>    call    _printf
>>    movl    16(%esp), %eax
>>    addl    $20, %esp
>>    ret
>>    .data
>>                                                            ; @.str
>> $_.str:
>>    db    "hello world\n\000"
>>
>> Aparently, gcc doesn't recognize ; as comments nor can it handle
the db
>> directive.
>> How can I generate assembly that is accepted by gcc ??
>>
>> Thx!
>>
>> Alex
>>
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>