[clang] [Clang] CGCoroutines skip emitting try block for value returning `noexcept` init `await_resume` calls (PR #73160)

[Yuxuan Chen via cfe-commits]

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@@ -129,14 +129,48 @@ static SmallString<32> buildSuspendPrefixStr(CGCoroData &Coro, AwaitKind Kind) {
   return Prefix;
 }
 
-static bool memberCallExpressionCanThrow(const Expr *E) {
-  if (const auto *CE = dyn_cast<CXXMemberCallExpr>(E))
-    if (const auto *Proto =
-            CE->getMethodDecl()->getType()->getAs<FunctionProtoType>())
-      if (isNoexceptExceptionSpec(Proto->getExceptionSpecType()) &&
-          Proto->canThrow() == CT_Cannot)
-        return false;
-  return true;
+// Check if function can throw based on prototype noexcept, also works for
+// destructors which are implicitly noexcept but can be marked noexcept(false).
+static bool FunctionCanThrow(const FunctionDecl *D) {
+  const auto *Proto = D->getType()->getAs<FunctionProtoType>();
+  if (!Proto) {
+    // Function proto is not found, we conservatively assume throwing.
+    return true;
+  }
+  return !isNoexceptExceptionSpec(Proto->getExceptionSpecType()) ||
+         Proto->canThrow() != CT_Cannot;
+}
+
+static bool ResumeStmtCanThrow(const Stmt *S) {
+  if (const auto *CE = dyn_cast<CallExpr>(S)) {
+    const auto *Callee = CE->getDirectCallee();
+    if (!Callee)
+      // We don't have direct callee. Conservatively assume throwing.
+      return true;
+
+    if (FunctionCanThrow(Callee))
+      return true;
----------------
yuxuanchen1997 wrote:

The logic doesn't go this way. 

If a function can throw, the task of this (conservative) analysis is to return true and nothing else needs to be done. Otherwise, fall through and recursively visit all children, which may include Stmts that throw. 

https://github.com/llvm/llvm-project/pull/73160