[LLVMdev] hexcode from llvm

[Dale Johannesen]

On May 20, 2010, at 6:18 PM, JayaSus wrote:

>
> Hi Bill Wendling.
> I am trying to get a hexcode as shown below for mips processor using  
> llvm
>
> Disassembly of section .text:
>
> 00000000 <main>:
>   0:   27bdffe8        addiu   sp,sp,-24
>   4:   afbe0010        sw      s8,16(sp)
>   8:   03a0f021        move    s8,sp
>   c:   24020004        li      v0,4
>  10:   afc20008        sw      v0,8(s8)
>  14:   24020005        li      v0,5
>  18:   afc20004        sw      v0,4(s8)
>  1c:   8fc30008        lw      v1,8(s8)
>  20:   8fc20004        lw      v0,4(s8)
>  24:   00000000        nop
>  28:   00621021        addu    v0,v1,v0
>  2c:   afc20000        sw      v0,0(s8)
>  30:   03c0e821        move    sp,s8
> ....
>
> Is there any pass or buildin command for llvm to generate this. llvm- 
> dis
> will only generate the assembly code and not the hexcode.

I think what you want is to generate object code (.o file) and  
simultaneously produce a dump of the assembly code and the  
corresponding object code in hex; I've seen compilers that do that.    
llvm does not currently generate object code directly; it only  
generates assembly.  There are people working on generating object  
code directly.  I don't know of anybody working on generating the dump  
you want, but it should be easy enough once direct object code  
generation is in place.

The usual toolchain for what you want is
llvm-gcc -S  -> assembler source (.s)
assembler source -> as -> object file (.o)
object file -> disassembler

This can be conveniently hidden in a script.  I don't know what the  
disassembler is called on mips, though.

llvm-gcc -c generates an object file, but it does this by generating  
an assembler source file and invoking the assembler.

> Moreover how can I compile c code for mips using llvm-gcc? llvm-gcc - 
> b mips
> t.c complains it wouldn't know the -b option.

Neither do I:)   You need to build llvm-gcc so it targets mips.