[ObjC] Enable removal of more memory management functions - #8524
[ObjC] Enable removal of more memory management functions#8524AngeloD2022 wants to merge 2 commits into
Conversation
…anagement functions.
…g the suffix of register-specific ARC functions. Also added a more robust check that verifies the origin of runtime functions on dyld shared cache binaries.
|
|
| b"_objc_claimAutoreleasedReturnValue", | ||
| ]; | ||
|
|
||
| fn is_objc_rt_symbol_dscview(view: &BinaryView, symbol: &Symbol) -> bool { |
There was a problem hiding this comment.
Can you clarify what the purpose of this function is? What is it guarding against?
There was a problem hiding this comment.
I added that check just to be as precise as possible and reduce the reliance on only symbol names– because if I'm not mistaken, it's possible in principle for multiple different symbols with the same name to exist in a binary view. So although it's unlikely– if Apple includes a function in one of their shared cache libraries with the same name as a runtime memory management function, it won't be hidden like one.
|
|
||
| IGNORABLE_MEMORY_MANAGEMENT_FUNCTIONS.contains(&symbol_name) | ||
| // Normalize the name to also include register-specific functions (e.g. _objc_release_x19). | ||
| let symbol_name = util::strip_arc_reg_suffix(symbol_name); |
There was a problem hiding this comment.
This results in incorrect handling of objc_retain_xN calls. Converting them to a no-op will result in x0 having the incorrect value.
Consider this example:
This change results in:
It should be result->_internal = _initWithCFURLResponse[1]
|
Fixed by #8535 |
3 participants
_objc_claimAutoreleasedReturnValueto the list of ignorable memory management functions._objc_release_x19.