[PATCH] D96571: [ASan] Introduce a way set different ways of emitting module destructors.

[Dan Liew via Phabricator via llvm-commits]

delcypher created this revision.
delcypher added reviewers: kubamracek, yln, aralisza, kcc, vitalybuka.
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Previously there was no way to control how module destructors were emitted
by `ModuleAddressSanitizerPass`. However, we want language frontends (e.g. Clang)
to be able to decide how to emit these destructors (if at all).

This patch introduces the `AsanDtorKind` enum that represents the different ways
destructors can be emitted. There are currently only two valid ways to emit destructors.

- `Global` - Use `llvm.global_dtors`. This was the previous behavior and is the default.
- `None`   - Do not emit module destructors.

The `ModuleAddressSanitizerPass` and the various wrappers around it have been updated
to take the `AsanDtorKind` as an argument.

The `-asan-destructor-kind=` command line argument has been introduced to make this
easy to test from `opt`. If this argument is specified it overrides the value passed
to the `ModuleAddressSanitizerPass` constructor.

Note that `AsanDtorKind` is not `bool` because we will introduce a new way to
emit destructors in a subsequent patch.

Note that `AsanDtorKind` is given its own header file because if it is declared
in `Transforms/Instrumentation/AddressSanitizer.h` it leads to compile error
(Module is ambiguous) when trying to use it in
`clang/Basic/CodeGenOptions.def`.

rdar://71609176


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D96571

Files:
  llvm/include/llvm/Transforms/Instrumentation/AddressSanitizer.h
  llvm/include/llvm/Transforms/Instrumentation/AddressSanitizerOptions.h
  llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
  llvm/test/Instrumentation/AddressSanitizer/no_global_dtors.ll

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