[clang] [CodeGen] Implement Objective-C WebAssembly exception handling support (PR #215562)

[Heejin Ahn via cfe-commits]

Hendrik =?utf-8?q?Hübner?= <hhuebner at hhuebnerMacBookPro.local>,
Hendrik =?utf-8?q?Hübner?= <hhuebner at hhuebnerMacBookPro.local>,
Hendrik =?utf-8?q?Hübner?= <hhuebner at MacBookPro.lan>,
Hendrik =?utf-8?q?Hübner?= <hhuebner at MacBookPro.lan>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/215562 at github.com>


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@@ -1320,24 +1345,9 @@ void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
       Builder.CreateBr(ContBB);
   }
 
-  // Because in wasm we merge all catch clauses into one big catchpad, in case
-  // none of the types in catch handlers matches after we test against each of
-  // them, we should unwind to the next EH enclosing scope. We generate a call
-  // to rethrow function here to do that.
-  if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll) {
-    assert(WasmCatchStartBlock);
-    // Navigate for the "rethrow" block we created in emitWasmCatchPadBlock().
-    // Wasm uses landingpad-style conditional branches to compare selectors, so
-    // we follow the false destination for each of the cond branches to reach
-    // the rethrow block.
-    llvm::BasicBlock *RethrowBlock = WasmCatchStartBlock;
-    while (llvm::Instruction *TI = RethrowBlock->getTerminatorOrNull())
-      RethrowBlock = cast<llvm::CondBrInst>(TI)->getSuccessor(1);
-    assert(RethrowBlock != WasmCatchStartBlock && RethrowBlock->empty());
-    Builder.SetInsertPoint(RethrowBlock);
-    llvm::Function *RethrowInCatchFn =
-        CGM.getIntrinsic(llvm::Intrinsic::wasm_rethrow);
-    EmitNoreturnRuntimeCallOrInvoke(RethrowInCatchFn, {});
+  if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll &&
+      WasmCatchStartBlock) {
----------------
aheejin wrote:

Why this additional `WasmCatchStartBlock` condition? Isn't this always true when `EHPersonality::get(*this).isWasmPersonality()` is true?

https://github.com/llvm/llvm-project/pull/215562