[PATCH] Allocate MCSymbol Name intrusively only when required

[Pete Cooper]

Hi all

Recent work by Rafael and Duncan has greatly reduced the number of MCSymbol’s which are actually named.  In particular, temporary symbols typically don’t need names.  On the verify_uselist_order test case for example, only around 50,000 symbols have names out of 700,000 total symbols.

This patch moves the storage for the Name* itself to be allocated prior to the MCSymbol.  This is similar to how User allocates Use’s in a custom new/delete.

Given that a symbol is currently 48 bytes on MachO, this reduces it by 16% on the typical case.  I have other patches coming which will get us to 24-bytes which is on average half the current amount.

Cheers,
Pete

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