[LLVMdev] Purpose of PROLOG_LABEL in function prologue?

Eric Christopher echristo at apple.com
Tue Aug 3 15:14:39 PDT 2010


On Aug 3, 2010, at 3:12 PM, Eric Christopher wrote:

> 
> On Aug 3, 2010, at 3:04 PM, Cameron Esfahani wrote:
> 
>> I've been building/dumping some x86_64 code and I've noticed that each of the routines has 3 temporary symbols, à la:
>> 
>> _main:
>> 	pushq	%rbp
>> Ltmp18:
>> 	movq	%rsp, %rbp
>> Ltmp19:
>> 	subq	$320, %rsp
>> Ltmp20:
>> 	movl	%ecx, -276(%rbp)
>> 
>> I've tracked them back to emitPrologue in X86RegisterInfo.cpp.  I'm wonder what's their purpose?
>> 
>> They're filling up my symbol table...
> 
> 
> EH ranges for unwind info.  If you look later on in the file for the symbols you'll see them.

Oh, though they should be local and not exported at all.

-eric



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