[llvm-commits] [llvm] r76198 - in /llvm/trunk: docs/LangRef.html include/llvm-c/Core.h include/llvm/Attributes.h lib/AsmParser/LLLexer.cpp lib/AsmParser/LLParser.cpp lib/AsmParser/LLToken.h lib/CodeGen/PrologEpilogInserter.cpp lib/VMCore/Attribut

[Eli Friedman]

On Fri, Jul 17, 2009 at 1:51 PM, Anton
Korobeynikov<anton at korobeynikov.info> wrote:
>> Okay... can you at least put a nasty warning in LangRef that such code
>> is fundamentally undefined?
> In which place?

The docs for the naked attribute.

> define arm_apcscc void @_start() nounwind naked {
> entry:
>        %0 = tail call i32* asm "", "={sp}"() nounwind          ;
> <i32*> [#uses=1]
>        %1 = load i32* %0, align 4              ; <i32> [#uses=1]
>        %2 = tail call i32* asm "", "={sp}"() nounwind          ;
> <i32*> [#uses=1]
>        %3 = getelementptr i32* %2, i32 1               ; <i32*> [#uses=1]
>        %4 = bitcast i32* %3 to i8**            ; <i8**> [#uses=1]
>        %5 = tail call arm_apcscc  i32 @_main(i32 %1, i8** %4)
> noreturn nounwind                ; <i32> [#uses=0]
>        unreachable
> }
>
> which is normal inline asm code...

This is nasty code which depends on details of register allocation...

-Eli