[clang] 80872d7 - [CIR] Upstream StackSave and StackRestoreOp (#136426)
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Tue Apr 22 12:08:00 PDT 2025
Author: Amr Hesham
Date: 2025-04-22T21:07:57+02:00
New Revision: 80872d7a32cd335a7964df95e9fbcdee43eb1ad4
URL: https://github.com/llvm/llvm-project/commit/80872d7a32cd335a7964df95e9fbcdee43eb1ad4
DIFF: https://github.com/llvm/llvm-project/commit/80872d7a32cd335a7964df95e9fbcdee43eb1ad4.diff
LOG: [CIR] Upstream StackSave and StackRestoreOp (#136426)
This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support
Added:
clang/test/CIR/IR/stack-save-restore.cir
clang/test/CIR/Lowering/stack-save-restore.cir
Modified:
clang/include/clang/CIR/Dialect/IR/CIROps.td
clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
Removed:
################################################################################
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 81b447f31feca..a8fc2e755b269 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -1489,6 +1489,50 @@ def CallOp : CIR_CallOpBase<"call", [NoRegionArguments]> {
}]>];
}
+//===----------------------------------------------------------------------===//
+// StackSaveOp & StackRestoreOp
+//===----------------------------------------------------------------------===//
+
+def StackSaveOp : CIR_Op<"stacksave"> {
+ let summary = "remembers the current state of the function stack";
+ let description = [{
+ Saves current state of the function stack. Returns a pointer to an opaque object
+ that later can be passed into cir.stackrestore.
+ This is used during the lowering of variable length array allocas.
+
+ This operation corresponds to LLVM intrinsic `stacksave`.
+
+ ```mlir
+ %0 = cir.stacksave : <!u8i>
+ ```
+ }];
+
+ let results = (outs CIR_PointerType:$result);
+ let assemblyFormat = "attr-dict `:` qualified(type($result))";
+}
+
+def StackRestoreOp : CIR_Op<"stackrestore"> {
+ let summary = "restores the state of the function stack";
+ let description = [{
+ Restore the state of the function stack to the state it was
+ in when the corresponding cir.stacksave executed.
+ This is used during the lowering of variable length array allocas.
+
+ This operation corresponds to LLVM intrinsic `stackrestore`.
+
+ ```mlir
+ %0 = cir.alloca !cir.ptr<!u8i>, !cir.ptr<!cir.ptr<!u8i>>, ["saved_stack"] {alignment = 8 : i64}
+ %1 = cir.stacksave : <!u8i>
+ cir.store %1, %0 : !cir.ptr<!u8i>, !cir.ptr<!cir.ptr<!u8i>>
+ %2 = cir.load %0 : !cir.ptr<!cir.ptr<!u8i>>, !cir.ptr<!u8i>
+ cir.stackrestore %2 : !cir.ptr<!u8i>
+ ```
+ }];
+
+ let arguments = (ins CIR_PointerType:$ptr);
+ let assemblyFormat = "$ptr attr-dict `:` qualified(type($ptr))";
+}
+
//===----------------------------------------------------------------------===//
// UnreachableOp
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 07d57862eacc8..f25eaea05cf10 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -1553,6 +1553,8 @@ void ConvertCIRToLLVMPass::runOnOperation() {
CIRToLLVMGetGlobalOpLowering,
CIRToLLVMSelectOpLowering,
CIRToLLVMShiftOpLowering,
+ CIRToLLVMStackSaveOpLowering,
+ CIRToLLVMStackRestoreOpLowering,
CIRToLLVMTrapOpLowering,
CIRToLLVMUnaryOpLowering
// clang-format on
@@ -1598,6 +1600,21 @@ mlir::LogicalResult CIRToLLVMTrapOpLowering::matchAndRewrite(
return mlir::success();
}
+mlir::LogicalResult CIRToLLVMStackSaveOpLowering::matchAndRewrite(
+ cir::StackSaveOp op, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const {
+ const mlir::Type ptrTy = getTypeConverter()->convertType(op.getType());
+ rewriter.replaceOpWithNewOp<mlir::LLVM::StackSaveOp>(op, ptrTy);
+ return mlir::success();
+}
+
+mlir::LogicalResult CIRToLLVMStackRestoreOpLowering::matchAndRewrite(
+ cir::StackRestoreOp op, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const {
+ rewriter.replaceOpWithNewOp<mlir::LLVM::StackRestoreOp>(op, adaptor.getPtr());
+ return mlir::success();
+}
+
std::unique_ptr<mlir::Pass> createConvertCIRToLLVMPass() {
return std::make_unique<ConvertCIRToLLVMPass>();
}
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
index acb872b200b55..91329523c3b0f 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
@@ -262,6 +262,27 @@ class CIRToLLVMPtrStrideOpLowering
matchAndRewrite(cir::PtrStrideOp op, OpAdaptor,
mlir::ConversionPatternRewriter &) const override;
};
+
+class CIRToLLVMStackSaveOpLowering
+ : public mlir::OpConversionPattern<cir::StackSaveOp> {
+public:
+ using mlir::OpConversionPattern<cir::StackSaveOp>::OpConversionPattern;
+
+ mlir::LogicalResult
+ matchAndRewrite(cir::StackSaveOp op, OpAdaptor,
+ mlir::ConversionPatternRewriter &) const override;
+};
+
+class CIRToLLVMStackRestoreOpLowering
+ : public mlir::OpConversionPattern<cir::StackRestoreOp> {
+public:
+ using OpConversionPattern<cir::StackRestoreOp>::OpConversionPattern;
+
+ mlir::LogicalResult
+ matchAndRewrite(cir::StackRestoreOp op, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const override;
+};
+
} // namespace direct
} // namespace cir
diff --git a/clang/test/CIR/IR/stack-save-restore.cir b/clang/test/CIR/IR/stack-save-restore.cir
new file mode 100644
index 0000000000000..f98889ac1083a
--- /dev/null
+++ b/clang/test/CIR/IR/stack-save-restore.cir
@@ -0,0 +1,23 @@
+// Test the CIR operations can parse and print correctly (roundtrip)
+
+// RUN: cir-opt %s | cir-opt | FileCheck %s
+
+!u8i = !cir.int<u, 8>
+
+module {
+ cir.func @stack_save_restore() {
+ %0 = cir.stacksave : !cir.ptr<!u8i>
+ cir.stackrestore %0 : !cir.ptr<!u8i>
+ cir.return
+ }
+}
+
+//CHECK: module {
+
+//CHECK-NEXT: cir.func @stack_save_restore() {
+//CHECK-NEXT: %0 = cir.stacksave : !cir.ptr<!u8i>
+//CHECK-NEXT: cir.stackrestore %0 : !cir.ptr<!u8i>
+//CHECK-NEXT: cir.return
+//CHECK-NEXT: }
+
+//CHECK-NEXT: }
diff --git a/clang/test/CIR/Lowering/stack-save-restore.cir b/clang/test/CIR/Lowering/stack-save-restore.cir
new file mode 100644
index 0000000000000..9e30081e3f477
--- /dev/null
+++ b/clang/test/CIR/Lowering/stack-save-restore.cir
@@ -0,0 +1,26 @@
+// RUN: cir-opt %s -cir-to-llvm -o - | FileCheck %s -check-prefix=MLIR
+// RUN: cir-opt %s -cir-to-llvm -o - | mlir-translate -mlir-to-llvmir | FileCheck %s -check-prefix=LLVM
+
+!u8i = !cir.int<u, 8>
+
+module {
+ cir.func @stack_save() {
+ %0 = cir.stacksave : !cir.ptr<!u8i>
+ cir.stackrestore %0 : !cir.ptr<!u8i>
+ cir.return
+ }
+}
+
+// MLIR: module {
+// MLIR-NEXT: llvm.func @stack_save
+// MLIR-NEXT: %0 = llvm.intr.stacksave : !llvm.ptr
+// MLIR-NEXT: llvm.intr.stackrestore %0 : !llvm.ptr
+// MLIR-NEXT: llvm.return
+// MLIR-NEXT: }
+// MLIR-NEXT: }
+
+// LLVM: define void @stack_save() {
+// LLVM: %1 = call ptr @llvm.stacksave.p0()
+// LLVM: call void @llvm.stackrestore.p0(ptr %1)
+// LLVM: ret void
+// LLVM: }
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