[PATCH v2] LoongArch: Fix the infinite loop caused by calling undefweak symbol

[Xi Ruoyao]

On Wed, 2024-11-20 at 09:28 +0800, Lulu Cai wrote:
> The undefweak symbol value of non-default visibility is 0 and does
> not use plt entry, and will not be relocated in the relocate_secion
> function. As a result, an infinite loop is generated because
> bl %plt(sym) => bl 0.
> 
> Fix this by converting the bl/call36 instructions to nop or removing
> them.

IMO it's better to convert it to "jirl $ra, $zero, 0".  Semantically an
undefined weak symbol should be resolved to address 0 so we should make
a call to address 0, instead of silently ignore the call.

Also "b %plt(sym)" should be turned to "jirl $zero, $zero, 0" as well
when sym is non-default visibility and weak undefined.

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University