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[CIR][CIRGen] Implement array cookie ABI for AppleARM64 targets (#1301)
This change introduces CIRGenCXXABI subclasses for ARM and AppleARM64 and implements ARM CXXABI handling for array cookies.
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3 files changed

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‎clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp

+80-5
Original file line numberDiff line numberDiff line change
@@ -360,6 +360,30 @@ class CIRGenItaniumCXXABI : public CIRGenCXXABI {
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classifyRTTIUniqueness(QualType CanTy, cir::GlobalLinkageKind Linkage) const;
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friend class CIRGenItaniumRTTIBuilder;
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};
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class CIRGenARMCXXABI : public CIRGenItaniumCXXABI {
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public:
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CIRGenARMCXXABI(CIRGenModule &CGM) : CIRGenItaniumCXXABI(CGM) {
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// TODO(cir): When implemented, /*UseARMMethodPtrABI=*/true,
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// /*UseARMGuardVarABI=*/true) {}
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assert(!cir::MissingFeatures::appleArm64CXXABI());
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}
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CharUnits getArrayCookieSizeImpl(QualType elementType) override;
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Address initializeArrayCookie(CIRGenFunction &CGF, Address NewPtr,
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mlir::Value NumElements, const CXXNewExpr *E,
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QualType ElementType) override;
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};
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class CIRGenAppleARM64CXXABI : public CIRGenARMCXXABI {
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public:
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CIRGenAppleARM64CXXABI(CIRGenModule &CGM) : CIRGenARMCXXABI(CGM) {
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Use32BitVTableOffsetABI = true;
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}
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// ARM64 libraries are prepared for non-unique RTTI.
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bool shouldRTTIBeUnique() const override { return false; }
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};
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} // namespace
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CIRGenCXXABI::AddedStructorArgs CIRGenItaniumCXXABI::getImplicitConstructorArgs(
@@ -404,12 +428,11 @@ CIRGenCXXABI *clang::CIRGen::CreateCIRGenItaniumCXXABI(CIRGenModule &CGM) {
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switch (CGM.getASTContext().getCXXABIKind()) {
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case TargetCXXABI::GenericItanium:
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case TargetCXXABI::GenericAArch64:
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case TargetCXXABI::AppleARM64:
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// TODO: this isn't quite right, clang uses AppleARM64CXXABI which inherits
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// from ARMCXXABI. We'll have to follow suit.
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assert(!cir::MissingFeatures::appleArm64CXXABI());
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return new CIRGenItaniumCXXABI(CGM);
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case TargetCXXABI::AppleARM64:
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return new CIRGenAppleARM64CXXABI(CGM);
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default:
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llvm_unreachable("bad or NYI ABI kind");
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}
@@ -2700,4 +2723,56 @@ Address CIRGenItaniumCXXABI::initializeArrayCookie(CIRGenFunction &CGF,
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auto OffsetOp = CGF.getBuilder().getSignedInt(Loc, Offset, /*width=*/32);
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auto DataPtr = CGF.getBuilder().createPtrStride(Loc, CastOp, OffsetOp);
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return Address(DataPtr, NewPtr.getType(), NewPtr.getAlignment());
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}
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}
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CharUnits CIRGenARMCXXABI::getArrayCookieSizeImpl(QualType elementType) {
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// ARM says that the cookie is always:
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// struct array_cookie {
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// std::size_t element_size; // element_size != 0
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// std::size_t element_count;
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// };
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// But the base ABI doesn't give anything an alignment greater than
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// 8, so we can dismiss this as typical ABI-author blindness to
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// actual language complexity and round up to the element alignment.
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return std::max(CharUnits::fromQuantity(2 * CGM.SizeSizeInBytes),
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getContext().getTypeAlignInChars(elementType));
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}
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Address CIRGenARMCXXABI::initializeArrayCookie(CIRGenFunction &cgf,
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Address newPtr,
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mlir::Value numElements,
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const CXXNewExpr *expr,
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QualType elementType) {
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assert(requiresArrayCookie(expr));
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// The cookie is always at the start of the buffer.
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auto cookiePtr =
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cgf.getBuilder().createPtrBitcast(newPtr.getPointer(), cgf.SizeTy);
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Address cookie = Address(cookiePtr, cgf.SizeTy, newPtr.getAlignment());
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ASTContext &ctx = getContext();
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CharUnits sizeSize = cgf.getSizeSize();
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mlir::Location loc = cgf.getLoc(expr->getSourceRange());
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// The first element is the element size.
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mlir::Value elementSize = cgf.getBuilder().getConstInt(
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loc, cgf.SizeTy, ctx.getTypeSizeInChars(elementType).getQuantity());
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cgf.getBuilder().createStore(loc, elementSize, cookie);
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// The second element is the element count.
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auto offsetOp = cgf.getBuilder().getSignedInt(loc, 1, /*width=*/32);
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auto dataPtr =
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cgf.getBuilder().createPtrStride(loc, cookie.getPointer(), offsetOp);
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cookie = Address(dataPtr, cgf.SizeTy, newPtr.getAlignment());
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cgf.getBuilder().createStore(loc, numElements, cookie);
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// Finally, compute a pointer to the actual data buffer by skipping
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// over the cookie completely.
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CharUnits cookieSize = CIRGenARMCXXABI::getArrayCookieSizeImpl(elementType);
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offsetOp = cgf.getBuilder().getSignedInt(loc, cookieSize.getQuantity(),
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/*width=*/32);
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auto castOp = cgf.getBuilder().createPtrBitcast(
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newPtr.getPointer(), cgf.getBuilder().getUIntNTy(8));
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dataPtr = cgf.getBuilder().createPtrStride(loc, castOp, offsetOp);
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return Address(dataPtr, newPtr.getType(), newPtr.getAlignment());
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}

‎clang/test/CIR/CodeGen/applearm64-array-cookies.cpp

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@@ -0,0 +1,54 @@
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// RUN: %clang_cc1 -std=c++20 -triple=arm64e-apple-darwin -fclangir -emit-cir %s -o %t.cir
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// RUN: FileCheck --input-file=%t.cir %s
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class C {
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public:
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~C();
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};
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void t_constant_size_nontrivial() {
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auto p = new C[3];
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}
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// CHECK: cir.func @_Z26t_constant_size_nontrivialv()
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// CHECK: %[[#NUM_ELEMENTS:]] = cir.const #cir.int<3> : !u64i
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// CHECK: %[[#SIZE_WITHOUT_COOKIE:]] = cir.const #cir.int<3> : !u64i
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// CHECK: %[[#ALLOCATION_SIZE:]] = cir.const #cir.int<19> : !u64i
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// CHECK: %[[#ALLOC_PTR:]] = cir.call @_Znam(%[[#ALLOCATION_SIZE]]) : (!u64i) -> !cir.ptr<!void>
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// CHECK: %[[#COOKIE_PTR:]] = cir.cast(bitcast, %[[#ALLOC_PTR]] : !cir.ptr<!void>), !cir.ptr<!u64i>
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// CHECK: %[[#ELEMENT_SIZE:]] = cir.const #cir.int<1> : !u64i
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// CHECK: cir.store %[[#ELEMENT_SIZE]], %[[#COOKIE_PTR]] : !u64i, !cir.ptr<!u64i>
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// CHECK: %[[#SECOND_COOKIE_OFFSET:]] = cir.const #cir.int<1> : !s32i
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// CHECK: %[[#COOKIE_PTR2:]] = cir.ptr_stride(%[[#COOKIE_PTR]] : !cir.ptr<!u64i>, %[[#SECOND_COOKIE_OFFSET]] : !s32i), !cir.ptr<!u64i>
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// CHECK: cir.store %[[#NUM_ELEMENTS]], %[[#COOKIE_PTR2]] : !u64i, !cir.ptr<!u64i>
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// CHECK: %[[#COOKIE_SIZE:]] = cir.const #cir.int<16> : !s32i
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// CHECK: %[[#ALLOC_AS_I8:]] = cir.cast(bitcast, %[[#ALLOC_PTR]] : !cir.ptr<!void>), !cir.ptr<!u8i>
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// CHECK: cir.ptr_stride(%[[#ALLOC_AS_I8]] : !cir.ptr<!u8i>, %[[#COOKIE_SIZE]] : !s32i), !cir.ptr<!u8i>
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class D {
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public:
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int x;
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~D();
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};
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void t_constant_size_nontrivial2() {
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auto p = new D[3];
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}
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// In this test SIZE_WITHOUT_COOKIE isn't used, but it would be if there were
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// an initializer.
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// CHECK: cir.func @_Z27t_constant_size_nontrivial2v()
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// CHECK: %[[#NUM_ELEMENTS:]] = cir.const #cir.int<3> : !u64i
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// CHECK: %[[#SIZE_WITHOUT_COOKIE:]] = cir.const #cir.int<12> : !u64i
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// CHECK: %[[#ALLOCATION_SIZE:]] = cir.const #cir.int<28> : !u64i
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// CHECK: %[[#ALLOC_PTR:]] = cir.call @_Znam(%[[#ALLOCATION_SIZE]]) : (!u64i) -> !cir.ptr<!void>
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// CHECK: %[[#COOKIE_PTR:]] = cir.cast(bitcast, %[[#ALLOC_PTR]] : !cir.ptr<!void>), !cir.ptr<!u64i>
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// CHECK: %[[#ELEMENT_SIZE:]] = cir.const #cir.int<4> : !u64i
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// CHECK: cir.store %[[#ELEMENT_SIZE]], %[[#COOKIE_PTR]] : !u64i, !cir.ptr<!u64i>
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// CHECK: %[[#SECOND_COOKIE_OFFSET:]] = cir.const #cir.int<1> : !s32i
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// CHECK: %[[#COOKIE_PTR2:]] = cir.ptr_stride(%[[#COOKIE_PTR]] : !cir.ptr<!u64i>, %[[#SECOND_COOKIE_OFFSET]] : !s32i), !cir.ptr<!u64i>
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// CHECK: cir.store %[[#NUM_ELEMENTS]], %[[#COOKIE_PTR2]] : !u64i, !cir.ptr<!u64i>
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// CHECK: %[[#COOKIE_SIZE:]] = cir.const #cir.int<16> : !s32i
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// CHECK: %[[#ALLOC_AS_I8:]] = cir.cast(bitcast, %[[#ALLOC_PTR]] : !cir.ptr<!void>), !cir.ptr<!u8i>
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// CHECK: cir.ptr_stride(%[[#ALLOC_AS_I8]] : !cir.ptr<!u8i>, %[[#COOKIE_SIZE]] : !s32i), !cir.ptr<!u8i>

‎clang/test/CIR/Lowering/applearm64-new.cpp

+41
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@@ -0,0 +1,41 @@
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// RUN: %clang_cc1 -triple=arm64e-apple-darwin -fclangir -emit-llvm %s -o %t.ll
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// RUN: FileCheck --input-file=%t.ll %s -check-prefix=LLVM
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class C {
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public:
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~C();
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};
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void t_constant_size_nontrivial() {
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auto p = new C[3];
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}
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// Note: The below differs from the IR emitted by clang without -fclangir in
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// several respects. (1) The alloca here has an extra "i64 1"
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// (2) The operator new call is missing "noalias noundef nonnull" on
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// the call and "noundef" on the argument, (3) The getelementptr is
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// missing "inbounds"
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// LLVM: @_Z26t_constant_size_nontrivialv()
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// LLVM: %[[COOKIE_PTR:.*]] = call ptr @_Znam(i64 19)
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// LLVM: store i64 1, ptr %[[COOKIE_PTR]], align 8
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// LLVM: %[[NUM_ELEMENTS_PTR:.*]] = getelementptr i64, ptr %[[COOKIE_PTR]], i64 1
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// LLVM: store i64 3, ptr %[[NUM_ELEMENTS_PTR]], align 8
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// LLVM: %[[ALLOCATED_PTR:.*]] = getelementptr i8, ptr %[[COOKIE_PTR]], i64 16
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class D {
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public:
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int x;
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~D();
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};
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void t_constant_size_nontrivial2() {
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auto p = new D[3];
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}
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// LLVM: @_Z27t_constant_size_nontrivial2v()
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// LLVM: %[[COOKIE_PTR:.*]] = call ptr @_Znam(i64 28)
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// LLVM: store i64 4, ptr %[[COOKIE_PTR]], align 8
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// LLVM: %[[NUM_ELEMENTS_PTR:.*]] = getelementptr i64, ptr %[[COOKIE_PTR]], i64 1
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// LLVM: store i64 3, ptr %[[NUM_ELEMENTS_PTR]], align 8
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// LLVM: %[[ALLOCATED_PTR:.*]] = getelementptr i8, ptr %[[COOKIE_PTR]], i64 16

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