[clang] [CIR] Upstream Exception CXXTryStmt (PR #162528)

[Andy Kaylor via cfe-commits]

================
@@ -69,6 +69,151 @@ mlir::LogicalResult CIRGenFunction::emitCXXTryStmt(const CXXTryStmt &s) {
   if (s.getTryBlock()->body_empty())
     return mlir::LogicalResult::success();
 
-  cgm.errorNYI("exitCXXTryStmt: CXXTryStmt with non-empty body");
-  return mlir::LogicalResult::success();
+  mlir::Location loc = getLoc(s.getSourceRange());
+  // Create a scope to hold try local storage for catch params.
+
+  mlir::OpBuilder::InsertPoint scopeIP;
+  cir::ScopeOp::create(
+      builder, loc,
+      /*scopeBuilder=*/[&](mlir::OpBuilder &b, mlir::Location loc) {
+        scopeIP = builder.saveInsertionPoint();
+      });
+
+  mlir::OpBuilder::InsertionGuard guard(builder);
+  builder.restoreInsertionPoint(scopeIP);
+  mlir::LogicalResult result = emitCXXTryStmtUnderScope(s);
+  cir::YieldOp::create(builder, loc);
+  return result;
+}
+
+mlir::LogicalResult
+CIRGenFunction::emitCXXTryStmtUnderScope(const CXXTryStmt &s) {
+  const llvm::Triple &t = getTarget().getTriple();
+  // If we encounter a try statement on in an OpenMP target region offloaded to
+  // a GPU, we treat it as a basic block.
+  const bool isTargetDevice =
+      (cgm.getLangOpts().OpenMPIsTargetDevice && (t.isNVPTX() || t.isAMDGCN()));
+  if (isTargetDevice) {
+    cgm.errorNYI(
+        "emitCXXTryStmtUnderScope: OpenMP target region offloaded to GPU");
+    return mlir::success();
+  }
+
+  unsigned numHandlers = s.getNumHandlers();
+  mlir::Location tryLoc = getLoc(s.getBeginLoc());
+  mlir::OpBuilder::InsertPoint beginInsertTryBody;
+
+  bool hasCatchAll = false;
+  for (unsigned i = 0; i != numHandlers; ++i) {
+    hasCatchAll |= s.getHandler(i)->getExceptionDecl() == nullptr;
+    if (hasCatchAll)
+      break;
+  }
+
+  // Create the scope to represent only the C/C++ `try {}` part. However,
+  // don't populate right away. Reserve some space to store the exception
+  // info but don't emit the bulk right away, for now only make sure the
----------------
andykaylor wrote:

```suggestion
  // don't populate right away. Create regions for the catch handlers,
  // but don't emit the handler bodies yet. For now, only make sure the
```
I think this is what the comment meant? It's not clear to me in what way this is making sure the scope returns the exception info.

https://github.com/llvm/llvm-project/pull/162528