[all-commits] [llvm/llvm-project] ed4194: [WebAssembly] Fix call unwind mismatches

[Heejin Ahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ed41945faadab27036d368cda9223dc3cb6eb840
      https://github.com/llvm/llvm-project/commit/ed41945faadab27036d368cda9223dc3cb6eb840
  Author: Heejin Ahn <aheejin at gmail.com>
  Date:   2021-02-06 (Sat, 06 Feb 2021)

  Changed paths:
    M llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.cpp
    M llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.h
    M llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
    M llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
    M llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll

  Log Message:
  -----------
  [WebAssembly] Fix call unwind mismatches

This adds `delegate` instruction and use it to fix unwind destination
mismatches created by marker placement in CFGStackify.

There are two kinds of unwind destination mismatches:
- Mismatches caused by throwing instructions (here we call it "call
  unwind mismatches", even though `throw` and `rethrow` can also cause
  mismatches)
- Mismatches caused by `catch`es, in case a foreign exception is not
  caught by the nearest `catch` and the next outer `catch` is not the
  catch it should unwind to. This kind of mismatches didn't exist in the
  previous version of the spec, because in the previous spec `catch` was
  effectively `catch_all`, catching all exceptions.

This implements routines to fix the first kind of unwind mismatches,
which we call "call unwind mismatches". The second mismatch (catch
unwind mismatches) will be fixed in a later CL.

This also reenables all previously disabled tests in cfg-stackify-eh.ll
and updates FileCheck lines to match the new spec. Two tests were
deleted because they specifically tested the way we fixed unwind
mismatches before using `exnref`s and branches, which we don't do
anymore.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94048