[Lldb-commits] [PATCH] D71487: [LLDB] Fix address computation for inline function

[Paul Robinson via Phabricator via lldb-commits]

probinson added a comment.

In D71487#1791824 <https://reviews.llvm.org/D71487#1791824>, @clayborg wrote:

> BTW: is used to be that both DW_AT_low_pc and DW_AT_high_pc would be set to zero when a function was dead stripped. This was back when both the low and high pc used DW_FORM_addr (a file address). But then DWARF changed such that DW_AT_high_pc could be encoded as a data form: DW_FORM_data1, DW_FORM_data2, DW_FORM_data4, or DW_FORM_data8. This is used to mean it is an offset from the low PC. Seems the linkers now didn't have a relocation for the DW_AT_high_pc so they couldn't zero it out. This is sad because we can end up with many functions at address zero that didn't get linked, and if zero is a valid address, then our DWARF contains a bunch of useless info that only hides which function is the real function for address zero.


One solution, which we do in Sony, is to make the linker fix up undefined references to be -1 instead of 0 (at least, in the .debug_* sections).  That's more obviously an invalid address.  Doesn't help with existing objects in the wild but I'd like to keep that idea in the air as a forward evolutionary step.


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https://reviews.llvm.org/D71487