[LLVMdev] Extra padding on DWARF debug info?

[Devang Patel]

On Apr 13, 2011, at 8:42 AM, Ken Dyck wrote:

> DwarfDebug::emitDebugInfo() always appends four zero bytes to the tail
> of the debug info section:
> 
>    emitDIE(Die);
>    // FIXME - extra padding for gdb bug.
>    Asm->OutStreamer.AddComment("4 extra padding bytes for GDB");
>    Asm->EmitInt8(0);
>    Asm->EmitInt8(0);
>    Asm->EmitInt8(0);
>    Asm->EmitInt8(0);
>    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("info_end", TheCU->getID()));
> 
> Does anybody know what the bug is in GDB that this works around? The
> workaround was added as part of r103439[1], which added support for
> multiple compilation units in one module. Does the bug ever affect
> modules with only a single compilation unit?
> 

It was not added by r103439. In fact, it was added by r32035.

http://llvm.org/viewvc/llvm-project?view=rev&revision=32035 

Unfortunately the log message and comments do not provide any hints, and I do not have access to the author anymore.

-
Devang



> -Ken
> 
> [1] http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20100510/101040.html

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