Lower `@llvm.global_dtors` using `__cxa_atexit` on MachO

For MachO, lower `@llvm.global_dtors` into `@llvm_global_ctors` with
`__cxa_atexit` calls to avoid emitting the deprecated `__mod_term_func`.

Reuse the existing `WebAssemblyLowerGlobalDtors.cpp` to accomplish this.

Enable fallback to the old behavior via Clang driver flag
(`-fregister-global-dtors-with-atexit`) or llc / code generation flag
(`-lower-global-dtors-via-cxa-atexit`).  This escape hatch will be
removed in the future.

Differential Revision: https://reviews.llvm.org/D121736

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index 7e7fb42..d501838 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -58,6 +58,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
   initializeLiveStacksPass(Registry);
   initializeLiveVariablesPass(Registry);
   initializeLocalStackSlotPassPass(Registry);
+  initializeLowerGlobalDtorsLegacyPassPass(Registry);
   initializeLowerIntrinsicsPass(Registry);
   initializeMIRAddFSDiscriminatorsPass(Registry);
   initializeMIRCanonicalizerPass(Registry);