[clang] [CIR] Upstream the CatchParamOp (PR #165110)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clangir

Author: Amr Hesham (AmrDeveloper)

<details>
<summary>Changes</summary>

Upstream the CatchParamOp as a prerequisite for implementing exception handlers

Issue https://github.com/llvm/llvm-project/issues/154992

---
Full diff: https://github.com/llvm/llvm-project/pull/165110.diff


4 Files Affected:

- (modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+44) 
- (modified) clang/lib/CIR/Dialect/IR/CIRDialect.cpp (+17) 
- (modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+29) 
- (added) clang/test/CIR/IR/invalid-catch-param.cir (+65) 


``````````diff
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 2b361ed0982c6..57736cd9c93c2 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -4490,6 +4490,50 @@ def CIR_TryOp : CIR_Op<"try",[
   let hasLLVMLowering = false;
 }
 
+//===----------------------------------------------------------------------===//
+// CatchParamOp
+//===----------------------------------------------------------------------===//
+
+def CIR_CatchParamKind  : CIR_I32EnumAttr<
+  "CatchParamKind", "Designate limits for begin/end of catch param handling", [
+    I32EnumAttrCase<"Begin", 0, "begin">,
+    I32EnumAttrCase<"End",  1, "end">
+]>;
+
+def CIR_CatchParamOp : CIR_Op<"catch_param"> {
+  let summary = "Represents catch clause formal parameter";
+  let description = [{
+    The `cir.catch_param` can operate in two modes: within catch regions of
+    `cir.try` or anywhere else with the `begin` or `end` markers. The `begin`
+    version requires an exception pointer of `cir.ptr<!void>`.
+
+    Example:
+
+    ```mlir
+    %exception = cir.catch_param begin %exception_obj -> !cir.ptr<!s32i>
+
+    %exception = cir.catch_param -> !cir.ptr<!void>
+
+    cir.catch_param end
+    ```
+  }];
+
+  let arguments = (ins
+    Optional<CIR_VoidPtrType>:$exception_ptr,
+    OptionalAttr<CIR_CatchParamKind>:$kind
+  );
+
+  let results = (outs Optional<CIR_AnyType>:$param);
+  let assemblyFormat = [{
+    ($kind^)?
+    ($exception_ptr^)?
+    (`->` qualified(type($param))^)?
+    attr-dict
+  }];
+
+  let hasVerifier = 1;
+}
+
 //===----------------------------------------------------------------------===//
 // Atomic operations
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Dialect/IR/CIRDialect.cpp b/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
index 2d2ef422bfaef..3531af762fabf 100644
--- a/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
+++ b/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
@@ -3096,6 +3096,23 @@ static mlir::ParseResult parseTryHandlerRegions(
   return mlir::success();
 }
 
+//===----------------------------------------------------------------------===//
+// CatchParamOp
+//===----------------------------------------------------------------------===//
+
+LogicalResult cir::CatchParamOp::verify() {
+  std::optional<cir::CatchParamKind> kind = getKind();
+  if (getExceptionPtr()) {
+    if (!kind || *kind != cir::CatchParamKind::Begin)
+      return emitOpError("needs 'begin' to work with exception pointer");
+    return success();
+  }
+
+  if (!kind && !(*this)->getParentOfType<cir::TryOp>())
+    return emitOpError("without 'kind' requires 'cir.try' surrounding scope");
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // TableGen'd op method definitions
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 5a6193fa8d840..b4c815065b2af 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -2981,6 +2981,35 @@ mlir::LogicalResult CIRToLLVMThrowOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+mlir::LogicalResult CIRToLLVMCatchParamOpLowering::matchAndRewrite(
+    cir::CatchParamOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  std::optional<cir::CatchParamKind> kind = op.getKind();
+  if (!kind)
+    llvm_unreachable("only begin/end supposed to make to lowering stage");
+
+  if (kind == cir::CatchParamKind::Begin) {
+    // Get or create `declare ptr @__cxa_begin_catch(ptr)`
+    const llvm::StringRef fnName = "__cxa_begin_catch";
+    auto llvmPtrTy = mlir::LLVM::LLVMPointerType::get(rewriter.getContext());
+    auto fnTy = mlir::LLVM::LLVMFunctionType::get(llvmPtrTy, {llvmPtrTy});
+    createLLVMFuncOpIfNotExist(rewriter, op, fnName, fnTy);
+    rewriter.replaceOpWithNewOp<mlir::LLVM::CallOp>(
+        op, mlir::TypeRange{llvmPtrTy}, fnName,
+        mlir::ValueRange{adaptor.getExceptionPtr()});
+    return mlir::success();
+  }
+
+  // Get or create `declare void @__cxa_end_catch()`
+  const llvm::StringRef fnName = "__cxa_end_catch";
+  auto voidTy = mlir::LLVM::LLVMVoidType::get(rewriter.getContext());
+  auto fnTy = mlir::LLVM::LLVMFunctionType::get(voidTy, {});
+  createLLVMFuncOpIfNotExist(rewriter, op, fnName, fnTy);
+  rewriter.replaceOpWithNewOp<mlir::LLVM::CallOp>(op, mlir::TypeRange{}, fnName,
+                                                  mlir::ValueRange{});
+  return mlir::success();
+}
+
 mlir::LogicalResult CIRToLLVMAllocExceptionOpLowering::matchAndRewrite(
     cir::AllocExceptionOp op, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
diff --git a/clang/test/CIR/IR/invalid-catch-param.cir b/clang/test/CIR/IR/invalid-catch-param.cir
new file mode 100644
index 0000000000000..87e90b983da50
--- /dev/null
+++ b/clang/test/CIR/IR/invalid-catch-param.cir
@@ -0,0 +1,65 @@
+// RUN: cir-opt %s -verify-diagnostics -split-input-file
+
+!s32i = !cir.int<s, 32>
+!void = !cir.void
+
+module {
+
+cir.func dso_local @catch_param_without_kind_and_without_try_scope() {
+  // expected-error @below {{'cir.catch_param' op without 'kind' requires 'cir.try' surrounding scope}}
+  %0 = cir.catch_param -> !cir.ptr<!void>
+  cir.return
+}
+
+}
+
+// -----
+
+!s32i = !cir.int<s, 32>
+!void = !cir.void
+
+module {
+
+cir.func private @division() -> !s32i
+cir.func dso_local @catch_param_with_exception_ptr_but_without_kind() {
+  cir.scope {
+    cir.try {
+      %0 = cir.call @division() : () -> !s32i
+      cir.yield
+    } catch all {
+      %0 = cir.const #cir.ptr<null> : !cir.ptr<!void>
+      // expected-error @below {{'cir.catch_param' op needs 'begin' to work with exception pointer}}
+      %1 = cir.catch_param %0 -> !cir.ptr<!void>
+      cir.yield
+    }
+  }
+  cir.return
+}
+
+}
+
+// -----
+
+!s32i = !cir.int<s, 32>
+!void = !cir.void
+
+module {
+
+cir.func private @division() -> !s32i
+cir.func dso_local @catch_param_with_exception_ptr_but_with_end_kind() {
+  cir.scope {
+    cir.try {
+      %0 = cir.call @division() : () -> !s32i
+      cir.yield
+    } catch all {
+      %0 = cir.const #cir.ptr<null> : !cir.ptr<!void>
+      // expected-error @below {{'cir.catch_param' op needs 'begin' to work with exception pointer}}
+      %1 = cir.catch_param end %0 -> !cir.ptr<!void>
+      cir.yield
+    }
+  }
+  cir.return
+}
+
+}
+

``````````

</details>


https://github.com/llvm/llvm-project/pull/165110