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[CIR] Add support for comparisons between pointers to member functions (#1390)
The CIRGen support is already there. This PR adds LLVM lowering support for comparisons between pointers to member functions. Note that pointers to member functions could only be compared for equality.
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4 files changed

+113
-3
lines changed

4 files changed

+113
-3
lines changed

‎clang/lib/CIR/Dialect/Transforms/TargetLowering/CIRCXXABI.h

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -122,6 +122,10 @@ class CIRCXXABI {
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mlir::Value loweredRhs,
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mlir::OpBuilder &builder) const = 0;
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virtual mlir::Value lowerMethodCmp(cir::CmpOp op, mlir::Value loweredLhs,
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mlir::Value loweredRhs,
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mlir::OpBuilder &builder) const = 0;
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virtual mlir::Value
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lowerDataMemberBitcast(cir::CastOp op, mlir::Type loweredDstTy,
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mlir::Value loweredSrc,

‎clang/lib/CIR/Dialect/Transforms/TargetLowering/ItaniumCXXABI.cpp

Lines changed: 59 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -103,6 +103,10 @@ class ItaniumCXXABI : public CIRCXXABI {
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mlir::Value loweredRhs,
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mlir::OpBuilder &builder) const override;
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mlir::Value lowerMethodCmp(cir::CmpOp op, mlir::Value loweredLhs,
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mlir::Value loweredRhs,
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mlir::OpBuilder &builder) const override;
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mlir::Value lowerDataMemberBitcast(cir::CastOp op, mlir::Type loweredDstTy,
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mlir::Value loweredSrc,
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mlir::OpBuilder &builder) const override;
@@ -478,6 +482,61 @@ mlir::Value ItaniumCXXABI::lowerDataMemberCmp(cir::CmpOp op,
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loweredRhs);
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}
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mlir::Value ItaniumCXXABI::lowerMethodCmp(cir::CmpOp op, mlir::Value loweredLhs,
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mlir::Value loweredRhs,
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mlir::OpBuilder &builder) const {
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assert(op.getKind() == cir::CmpOpKind::eq ||
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op.getKind() == cir::CmpOpKind::ne);
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cir::IntType ptrdiffCIRTy = getPtrDiffCIRTy(LM);
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mlir::Value ptrdiffZero = builder.create<cir::ConstantOp>(
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op.getLoc(), ptrdiffCIRTy, cir::IntAttr::get(ptrdiffCIRTy, 0));
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mlir::Value lhsPtrField = builder.create<cir::ExtractMemberOp>(
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op.getLoc(), ptrdiffCIRTy, loweredLhs, 0);
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mlir::Value rhsPtrField = builder.create<cir::ExtractMemberOp>(
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op.getLoc(), ptrdiffCIRTy, loweredRhs, 0);
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mlir::Value ptrCmp = builder.create<cir::CmpOp>(op.getLoc(), op.getKind(),
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lhsPtrField, rhsPtrField);
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mlir::Value ptrCmpToNull = builder.create<cir::CmpOp>(
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op.getLoc(), op.getKind(), lhsPtrField, ptrdiffZero);
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mlir::Value lhsAdjField = builder.create<cir::ExtractMemberOp>(
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op.getLoc(), ptrdiffCIRTy, loweredLhs, 1);
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mlir::Value rhsAdjField = builder.create<cir::ExtractMemberOp>(
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op.getLoc(), ptrdiffCIRTy, loweredRhs, 1);
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mlir::Value adjCmp = builder.create<cir::CmpOp>(op.getLoc(), op.getKind(),
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lhsAdjField, rhsAdjField);
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// We use cir.select to represent "||" and "&&" operations below:
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// - cir.select if %a then %b else false => %a && %b
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// - cir.select if %a then true else %b => %a || %b
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// TODO: Do we need to invent dedicated "cir.logical_or" and "cir.logical_and"
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// operations for this?
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auto boolTy = cir::BoolType::get(op.getContext());
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mlir::Value trueValue = builder.create<cir::ConstantOp>(
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op.getLoc(), boolTy, cir::BoolAttr::get(op.getContext(), boolTy, true));
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mlir::Value falseValue = builder.create<cir::ConstantOp>(
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op.getLoc(), boolTy, cir::BoolAttr::get(op.getContext(), boolTy, false));
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auto create_and = [&](mlir::Value lhs, mlir::Value rhs) {
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return builder.create<cir::SelectOp>(op.getLoc(), lhs, rhs, falseValue);
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};
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auto create_or = [&](mlir::Value lhs, mlir::Value rhs) {
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return builder.create<cir::SelectOp>(op.getLoc(), lhs, trueValue, rhs);
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};
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mlir::Value result;
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if (op.getKind() == cir::CmpOpKind::eq) {
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// (lhs.ptr == null || lhs.adj == rhs.adj) && lhs.ptr == rhs.ptr
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result = create_and(create_or(ptrCmpToNull, adjCmp), ptrCmp);
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} else {
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// (lhs.ptr != null && lhs.adj != rhs.adj) || lhs.ptr != rhs.ptr
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result = create_or(create_and(ptrCmpToNull, adjCmp), ptrCmp);
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}
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return result;
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}
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mlir::Value
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ItaniumCXXABI::lowerDataMemberBitcast(cir::CastOp op, mlir::Type loweredDstTy,
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mlir::Value loweredSrc,

‎clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -2893,10 +2893,17 @@ mlir::LogicalResult CIRToLLVMCmpOpLowering::matchAndRewrite(
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mlir::ConversionPatternRewriter &rewriter) const {
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auto type = cmpOp.getLhs().getType();
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2896-
if (mlir::isa<cir::DataMemberType>(type)) {
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if (mlir::isa<cir::DataMemberType, cir::MethodType>(type)) {
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assert(lowerMod && "lowering module is not available");
2898-
mlir::Value loweredResult = lowerMod->getCXXABI().lowerDataMemberCmp(
2899-
cmpOp, adaptor.getLhs(), adaptor.getRhs(), rewriter);
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mlir::Value loweredResult;
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if (mlir::isa<cir::DataMemberType>(type))
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loweredResult = lowerMod->getCXXABI().lowerDataMemberCmp(
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cmpOp, adaptor.getLhs(), adaptor.getRhs(), rewriter);
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else
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loweredResult = lowerMod->getCXXABI().lowerMethodCmp(
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cmpOp, adaptor.getLhs(), adaptor.getRhs(), rewriter);
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rewriter.replaceOp(cmpOp, loweredResult);
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return mlir::success();
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}

‎clang/test/CIR/CodeGen/pointer-to-member-func.cpp

Lines changed: 40 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -78,3 +78,43 @@ void call(Foo *obj, void (Foo::*func)(int), int arg) {
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// LLVM-NEXT: %[[#arg:]] = load i32, ptr %{{.+}}
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// LLVM-NEXT: call void %[[#callee_ptr]](ptr %[[#adjusted_this]], i32 %[[#arg]])
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// LLVM: }
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bool cmp_eq(void (Foo::*lhs)(int), void (Foo::*rhs)(int)) {
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return lhs == rhs;
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}
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// CHECK-LABEL: @_Z6cmp_eqM3FooFviES1_
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// CHECK: %{{.+}} = cir.cmp(eq, %{{.+}}, %{{.+}}) : !cir.method<!cir.func<(!s32i)> in !ty_Foo>, !cir.bool
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// LLVM-LABEL: @_Z6cmp_eqM3FooFviES1_
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// LLVM: %[[#lhs:]] = load { i64, i64 }, ptr %{{.+}}
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// LLVM-NEXT: %[[#rhs:]] = load { i64, i64 }, ptr %{{.+}}
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// LLVM-NEXT: %[[#lhs_ptr:]] = extractvalue { i64, i64 } %[[#lhs]], 0
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// LLVM-NEXT: %[[#rhs_ptr:]] = extractvalue { i64, i64 } %[[#rhs]], 0
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// LLVM-NEXT: %[[#ptr_cmp:]] = icmp eq i64 %[[#lhs_ptr]], %[[#rhs_ptr]]
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// LLVM-NEXT: %[[#ptr_null:]] = icmp eq i64 %[[#lhs_ptr]], 0
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// LLVM-NEXT: %[[#lhs_adj:]] = extractvalue { i64, i64 } %[[#lhs]], 1
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// LLVM-NEXT: %[[#rhs_adj:]] = extractvalue { i64, i64 } %[[#rhs]], 1
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// LLVM-NEXT: %[[#adj_cmp:]] = icmp eq i64 %[[#lhs_adj]], %[[#rhs_adj]]
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// LLVM-NEXT: %[[#tmp:]] = or i1 %[[#ptr_null]], %[[#adj_cmp]]
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// LLVM-NEXT: %{{.+}} = and i1 %[[#tmp]], %[[#ptr_cmp]]
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bool cmp_ne(void (Foo::*lhs)(int), void (Foo::*rhs)(int)) {
103+
return lhs != rhs;
104+
}
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// CHECK-LABEL: @_Z6cmp_neM3FooFviES1_
107+
// CHECK: %{{.+}} = cir.cmp(ne, %{{.+}}, %{{.+}}) : !cir.method<!cir.func<(!s32i)> in !ty_Foo>, !cir.bool
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// LLVM-LABEL: @_Z6cmp_neM3FooFviES1_
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// LLVM: %[[#lhs:]] = load { i64, i64 }, ptr %{{.+}}
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// LLVM-NEXT: %[[#rhs:]] = load { i64, i64 }, ptr %{{.+}}
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// LLVM-NEXT: %[[#lhs_ptr:]] = extractvalue { i64, i64 } %[[#lhs]], 0
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// LLVM-NEXT: %[[#rhs_ptr:]] = extractvalue { i64, i64 } %[[#rhs]], 0
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// LLVM-NEXT: %[[#ptr_cmp:]] = icmp ne i64 %[[#lhs_ptr]], %[[#rhs_ptr]]
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// LLVM-NEXT: %[[#ptr_null:]] = icmp ne i64 %[[#lhs_ptr]], 0
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// LLVM-NEXT: %[[#lhs_adj:]] = extractvalue { i64, i64 } %[[#lhs]], 1
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// LLVM-NEXT: %[[#rhs_adj:]] = extractvalue { i64, i64 } %[[#rhs]], 1
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// LLVM-NEXT: %[[#adj_cmp:]] = icmp ne i64 %[[#lhs_adj]], %[[#rhs_adj]]
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// LLVM-NEXT: %[[#tmp:]] = and i1 %[[#ptr_null]], %[[#adj_cmp]]
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// LLVM-NEXT: %{{.+}} = or i1 %[[#tmp]], %[[#ptr_cmp]]

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