Re: [Libjit] Basic float32 issue

[Matthew Keeter]

This is no longer blocking me – it works when I compile the function into a 
closure,
and call it directly, but the jit_function_apply behavior is still strange / 
suspicious.

Thanks,
Matt

On Apr 17, 2016, at 12:45 PM, Aleksey Demakov <address@hidden> wrote:

> Hi Matt,
> 
> Thanks for the report. I will take a look into it in the next few days.
> 
> Regards,
> Aleksey
> 
> On Sun, Apr 17, 2016 at 7:52 AM, Matthew Keeter <address@hidden> wrote:
>> Digging a little deeper, the IR looks fine but the generated assembly is
>> missing a data / bss section with float constants:
>> 
>> Before compiling:
>> function test() : float32
>> .L:
>>        return_float32(19.000000)
>>        ends_in_dead
>> .L:
>> .L:
>> end
>> 
>> After compiling:
>> function test() : float32
>> 
>> /tmp/libjit-dump.o:     file format mach-o-x86-64
>> 
>> 
>> Disassembly of section .text:
>> 
>> 000000010413914c <.text>:
>>   10413914c:   55                      push   %rbp
>>   10413914d:   48 8b ec                mov    %rsp,%rbp
>>   104139150:   f3 0f 10 05 78 fe 00    movss  0xfe78(%rip),%xmm0        #
>> 0x104148fd0
>>   104139157:   00
>>   104139158:   48 8b e5                mov    %rbp,%rsp
>>   10413915b:   5d                      pop    %rbp
>>   10413915c:   c3                      retq
>> 
>> end
>> 
>> In particular, note that
>>    movss  0xfe78(%rip),%xmm0        # 0x104148fd0
>> is pointing off into space.
>> 
>> Does this ring any bells?
>> 
>> Thanks,
>> Matt
>> 
>> On Apr 16, 2016, at 9:09 PM, Matthew Keeter <address@hidden> wrote:
>> 
>> Hi all,
>> 
>> I’m having trouble with floating-point operations and have reduced to a very
>> simple test case.
>> The code below creates a function with no arguments that just returns a
>> float32 constant.
>> 
>> For some reason, instead of returning the constant’s value, it always gives
>> zero.
>> 
>> Identical code with jit_type_int works fine, so I’m puzzled as to what’s
>> going on.
>> Any ideas?  The code is pasted below
>> 
>> Thanks,
>> Matt
>> 
>> {
>>   jit_context_t context;
>>   jit_type_t signature;
>>   jit_function_t function;
>>   jit_value_t c;
>>   jit_float32 result;
>> 
>>   context = jit_context_create();
>>   jit_context_build_start(context);
>> 
>>   signature = jit_type_create_signature
>>       (jit_abi_cdecl, jit_type_float32, NULL, 0, 1);
>> 
>>   function = jit_function_create(context, signature);
>> 
>>   c = jit_value_create_float32_constant(function, jit_type_float32,
>> (jit_float32)13.0f);
>>   jit_insn_return(function, c);
>> 
>>   jit_function_compile(function);
>>   jit_context_build_end(context);
>>   jit_function_apply(function, NULL, &result);
>>   printf("const(13) = %f\n", (float)result);
>> 
>>   jit_context_destroy(context);
>> }
>> 
>>