Re: [avr-llvm-devel] Inline assembly.

[Stepan D. <stp...@na...>]

Exactly. You got assertion due to incorrect inlineasm instruction. I had also failed to reproduce this behavoiur for reduced case. This bug fired for big source only. Try compile that big source with -emit-llvm, and lookup inline asm (there is some variable with name, that ends with "m10", perhaps you recheck that name in .c file). I can attach result IR file with string number reference a bit later, currently I'm stucking in traffic jam :-(

-Stepan

> I've compiled the file you attached, ignoring all warnings i get from clang about the unknown attributes like progmem, i'm getting the assertion "multibyte index is out of range."
> 
> 2013/7/28 Borja Ferrer <bor...@gm...>
> 
>> Hello Stepan,
>>
>> 1) It seems clang mangles assembly functions names by prefixing a \01 character. I haven't found yet the code that does this depending on the target used.
>>
>> 2) About the code above, I'm assuming you got that inline asm code from the __LPM_dword_classic__ macro. This is what I'm getting for the following C code:
>> typedef unsigned int uint16_t;
>> typedef unsigned long uint32_t;
>>
>> #define __LPM_dword_classic__(addr) \
>> (__extension__({ \
>> uint16_t __addr16 = (uint16_t)(addr); \
>> uint32_t __result; \
>> __asm__ __volatile__ \
>>
>> ( \
>> "lpm" "\n\t" \
>> "mov %A0, r0" "\n\t" \
>> "adiw r30, 1" "\n\t" \
>>
>> "lpm" "\n\t" \
>> "mov %B0, r0" "\n\t" \
>> "adiw r30, 1" "\n\t" \
>> "lpm" "\n\t" \
>>
>> "mov %C0, r0" "\n\t" \
>> "adiw r30, 1" "\n\t" \
>> "lpm" "\n\t" \
>> "mov %D0, r0" "\n\t" \
>>
>> : "=r" (__result), "=z" (__addr16) \
>> : "1" (__addr16) \
>> : "r0" \
>>
>> ); \
>>
>> __result; \
>> }))
>> unsigned long inlineasm(unsigned int addr)
>> {
>> return __LPM_dword_classic__(addr);
>> }
>>
>> clang produces:
>>
>> define i32 @inlineasm(i16 %addr) #0 {
>>
>> entry:
>> %0 = tail call { i32, i16 } asm sideeffect "lpm\0A\09mov ${0:A}, r0\0A\09adiw r30, 1\0A\09lpm\0A\09mov ${0:B}, r0\0A\09adiw r30, 1\0A\09lpm\0A\09mov ${0:C}, r0\0A\09adiw r30, 1\0A\09lpm\0A\09mov ${0:D}, r0\0A\09", "=r,=z,1,~{r0}"(i16 %addr) #2, !srcloc !4
>>
>> %asmresult = extractvalue { i32, i16 } %0, 0
>> ret i32 %asmresult
>> }
>>
>> No truncations here as far i can tell. Try this code and see what you get.


 -- 
Truly yours,
Stepan Dyatkovskiy