[LLVMdev] lli : external functions and target datalayout

[Jianzhou Zhao]

On Sun, Oct 24, 2010 at 1:48 PM, Óscar Fuentes <ofv at wanadoo.es> wrote:
> Jianzhou Zhao <jianzhou at seas.upenn.edu> writes:
>
> [snip]
>
>> The other question is about
>> target datalayout =
>> "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
>>
>> If I use this string to creat a TargetData object directly, I got an
>> assertion error:
>>
>> ~/llvm-2.6/lib/Target/TargetData.cpp:246: void
>> llvm::TargetData::setAlignment(llvm::AlignTypeEnum, unsigned char,
>> unsigned char, uint32_t): Assertion `abi_align <= pref_align &&
>> "Preferred alignment worse than ABI!"' failed.
>> Aborted
>>
>> This is because of the i64:32:64. It seems to be i64:64:64. 'lli' is
>> able to fix this problem automatically, but why does llvm-gcc output
>> i64:32:64 rather than i64:64:64?
>
> FYI: the X86 data layout is hard-coded in
> lib/Target/X86/X86TargetMachine.cpp, so that assert is mostly bogus, and

Thanks. I should get the TargetData object from the ExecutionEngine class.

> the existence of "target datalayout" IR setting and
> Module::setDataLayout are deceiving.
>

Do you know if the latest release fixed this assertion? I actually
dont quite understand how this assertion affects the program.  Can I
use setDataLayout for other targets?

-- 
Jianzhou