Add changelog entries for how to undo default changes #13909
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| @@ -42,13 +42,15 @@ Current Trunk | |||
| - Use LLVM's new pass manager by default, as LLVM does. This changes a bunch of | |||
| things about how LLVM optimizes and inlines, so it may cause noticeable | |||
| changes in compile times, code size, and speed, either for better or for | |||
| worse. (#13427) | |||
| worse. You can use the old pass manager (until LLVM removes it) by passing | |||
| `-flegacy-pass-manager` (#13427) | |||
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Maybe mention the link flag too?
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How could that be used? --lto-legacy-pass-manager needs to be passed to wasm-ld but the user doesn't run it directly. Do we have a way to pass flags to it? (I don't see one.)
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Yes -Wl,--foo is the way to pass flags to the linker.
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Also, sadly even if the user passed both compiler and linker flags they won't effect the standard libraries (which have a fixed set of flags they build with).
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Oh, does emcc parse and pass those to wasm-ld?
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Yup.. except for a few that we don't support and want to silently ignore (UNSUPPORTED_LLD_FLAGS)
See #13899.