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[CIR] Upstream Exception EhInflight op #165621
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[CIR] Upstream Exception EhInflight op #165621
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@llvm/pr-subscribers-clang @llvm/pr-subscribers-clangir Author: Amr Hesham (AmrDeveloper) ChangesUpstream Exception EhInflight op as a prerequisite for full catch handlers implementation Issue #154992 Full diff: https://github.com/llvm/llvm-project/pull/165621.diff 3 Files Affected:
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 2b361ed0982c6..0497d97239000 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -4490,6 +4490,35 @@ def CIR_TryOp : CIR_Op<"try",[
let hasLLVMLowering = false;
}
+//===----------------------------------------------------------------------===//
+// Exception related: EhInflightOp
+//===----------------------------------------------------------------------===//
+
+def CIR_EhInflightOp : CIR_Op<"eh.inflight_exception"> {
+ let summary = "Materialize the catch clause formal parameter";
+ let description = [{
+ `cir.eh.inflight_exception` returns two values:
+ - `exception_ptr`: The exception pointer for the inflight exception
+ - `type_id`: pointer to the exception object
+ This operation is expected to be the first one basic blocks on the
+ exception path out of `cir.try_call` operations.
+
+ The `cleanup` attribute indicates that clean up code might run before the
+ values produced by this operation are used to gather exception information.
+ This helps CIR to pass down more accurate information for LLVM lowering
+ to landingpads.
+ }];
+
+ let arguments = (ins UnitAttr:$cleanup,
+ OptionalAttr<FlatSymbolRefArrayAttr>:$sym_type_list);
+ let results = (outs CIR_VoidPtrType:$exception_ptr, CIR_UInt32:$type_id);
+ let assemblyFormat = [{
+ (`cleanup` $cleanup^)?
+ ($sym_type_list^)?
+ attr-dict
+ }];
+}
+
//===----------------------------------------------------------------------===//
// Atomic operations
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 5a6193fa8d840..0bf5eb740096f 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -3002,6 +3002,88 @@ mlir::LogicalResult CIRToLLVMAllocExceptionOpLowering::matchAndRewrite(
return mlir::success();
}
+static mlir::LLVM::LLVMStructType
+getLLVMLandingPadStructTy(mlir::ConversionPatternRewriter &rewriter) {
+ // Create the landing pad type: struct { ptr, i32 }
+ mlir::MLIRContext *ctx = rewriter.getContext();
+ auto llvmPtr = mlir::LLVM::LLVMPointerType::get(ctx);
+ llvm::SmallVector<mlir::Type> structFields = {llvmPtr, rewriter.getI32Type()};
+ return mlir::LLVM::LLVMStructType::getLiteral(ctx, structFields);
+}
+
+mlir::LogicalResult CIRToLLVMEhInflightOpLowering::matchAndRewrite(
+ cir::EhInflightOp op, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const {
+ auto llvmFn = op->getParentOfType<mlir::LLVM::LLVMFuncOp>();
+ assert(llvmFn && "expected LLVM function parent");
+ mlir::Block *entryBlock = &llvmFn.getRegion().front();
+ assert(entryBlock->isEntryBlock());
+
+ mlir::ArrayAttr symListAttr = op.getSymTypeListAttr();
+ mlir::SmallVector<mlir::Value, 4> symAddrs;
+
+ auto llvmPtrTy = mlir::LLVM::LLVMPointerType::get(rewriter.getContext());
+ mlir::Location loc = op.getLoc();
+
+ // %landingpad = landingpad { ptr, i32 }
+ // Note that since llvm.landingpad has to be the first operation on the
+ // block, any needed value for its operands has to be added somewhere else.
+ if (symListAttr) {
+ // catch ptr @_ZTIi
+ // catch ptr @_ZTIPKc
+ for (mlir::Attribute attr : symListAttr) {
+ auto symAttr = cast<mlir::FlatSymbolRefAttr>(attr);
+ // Generate `llvm.mlir.addressof` for each symbol, and place those
+ // operations in the LLVM function entry basic block.
+ mlir::OpBuilder::InsertionGuard guard(rewriter);
+ rewriter.setInsertionPointToStart(entryBlock);
+ mlir::Value addrOp = mlir::LLVM::AddressOfOp::create(
+ rewriter, loc, llvmPtrTy, symAttr.getValue());
+ symAddrs.push_back(addrOp);
+ }
+ } else if (!op.getCleanup()) {
+ // catch ptr null
+ mlir::OpBuilder::InsertionGuard guard(rewriter);
+ rewriter.setInsertionPointToStart(entryBlock);
+ mlir::Value nullOp = mlir::LLVM::ZeroOp::create(rewriter, loc, llvmPtrTy);
+ symAddrs.push_back(nullOp);
+ }
+
+ // %slot = extractvalue { ptr, i32 } %x, 0
+ // %selector = extractvalue { ptr, i32 } %x, 1
+ mlir::LLVM::LLVMStructType llvmLandingPadStructTy =
+ getLLVMLandingPadStructTy(rewriter);
+ auto landingPadOp = mlir::LLVM::LandingpadOp::create(
+ rewriter, loc, llvmLandingPadStructTy, symAddrs);
+
+ if (op.getCleanup())
+ landingPadOp.setCleanup(true);
+
+ mlir::Value slot =
+ mlir::LLVM::ExtractValueOp::create(rewriter, loc, landingPadOp, 0);
+ mlir::Value selector =
+ mlir::LLVM::ExtractValueOp::create(rewriter, loc, landingPadOp, 1);
+ rewriter.replaceOp(op, mlir::ValueRange{slot, selector});
+
+ // Landing pads are required to be in LLVM functions with personality
+ // attribute.
+ // TODO(cir): for now hardcode personality creation in order to start
+ // adding exception tests, once we annotate CIR with such information,
+ // change it to be in FuncOp lowering instead.
+ mlir::OpBuilder::InsertionGuard guard(rewriter);
+ // Insert personality decl before the current function.
+ rewriter.setInsertionPoint(llvmFn);
+ auto personalityFnTy =
+ mlir::LLVM::LLVMFunctionType::get(rewriter.getI32Type(), {},
+ /*isVarArg=*/true);
+ // Get or create `__gxx_personality_v0`
+ const StringRef fnName = "__gxx_personality_v0";
+ createLLVMFuncOpIfNotExist(rewriter, op, fnName, personalityFnTy);
+ llvmFn.setPersonality(fnName);
+
+ return mlir::success();
+}
+
mlir::LogicalResult CIRToLLVMTrapOpLowering::matchAndRewrite(
cir::TrapOp op, OpAdaptor adaptor,
mlir::ConversionPatternRewriter &rewriter) const {
diff --git a/clang/test/CIR/IR/eh-inflight.cir b/clang/test/CIR/IR/eh-inflight.cir
new file mode 100644
index 0000000000000..90a5f3f67b6fe
--- /dev/null
+++ b/clang/test/CIR/IR/eh-inflight.cir
@@ -0,0 +1,15 @@
+// RUN: cir-opt %s --verify-roundtrip | FileCheck %s
+
+module {
+
+cir.func dso_local @function_with_inflight_exception() {
+ %exception_ptr, %type_id = cir.eh.inflight_exception
+ cir.return
+}
+
+// CHECK: cir.func dso_local @function_with_inflight_exception() {
+// CHECK: %exception_ptr, %type_id = cir.eh.inflight_exception
+// CHECK: cir.return
+// CHECK: }
+
+}
|
| return mlir::LLVM::LLVMStructType::getLiteral(ctx, structFields); | ||
| } | ||
|
|
||
| mlir::LogicalResult CIRToLLVMEhInflightOpLowering::matchAndRewrite( |
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We need a CIR -> LLVM test here
| // operations in the LLVM function entry basic block. | ||
| mlir::OpBuilder::InsertionGuard guard(rewriter); | ||
| rewriter.setInsertionPointToStart(entryBlock); | ||
| mlir::Value addrOp = mlir::LLVM::AddressOfOp::create( |
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It seems a bit strange that the LLVM landingpad op doesn't take flat symbol references. Won't this always be a global object?
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I am not sure if it takes ValueRange to be able to represent a null value 🤔
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Upstream Exception EhInflight op as a prerequisite for full catch handlers implementation
Issue #154992