[PATCH] D104230: [gold] Release input files in claim_file

Mon Jun 21 23:03:07 PDT 2021

tbaeder added a comment.

In D104230#2831318 <https://reviews.llvm.org/D104230#2831318>, @tejohnson wrote:

> Why aren't they being released at the end of runLTO (via the RAII PluginInputFile objects saved in the HandleToInputFile map) for both thin and regular LTO? I don't understand how this change is correct - we are saving the fd and handle here for use later in runLTO for both thin and regular LTO, but you will be releasing them early for regular lto.

They are being released, but we can't have that many fds open all at the same time. ld.bfd will call `claim_file` hundreds of times per file (depending on the file) and we end up with thousands of open fds.

IIRC the handle that's saved is later only used in the thinlto case and only relevant for `getSymbolsAndView()`.

I have tested calling `release_input_file()` for thinlto as well and it seems to just work if I remove the `PluginInfoFile` RAII code as well, but I was worried about this from the comments about thinlto and parallel backends.

Note that immediately closing the fd again is basically what ld.bfd is doing for "the/a GCC plugin" but doesn't for the LLVM plugin, which it tries to differentiate here: https://github.com/bminor/binutils-gdb/blob/master/ld/plugin.c#L1229-L1241.

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https://reviews.llvm.org/D104230