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[cxx-interop] Fix inline operators of address-only types. #32869

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[cxx-interop] Fix inline operators of address-only types. #32869

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16 changes: 15 additions & 1 deletion lib/SIL/IR/SILFunctionType.cpp
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Expand Up @@ -1572,13 +1572,27 @@ class DestructureInputs {
// Add any foreign parameters that are positioned here.
maybeAddForeignParameters();

bool isCxxOperator = origType.isCXXMethod() &&
origType.getCXXMethod()->isOverloadedOperator();

// Process all the non-self parameters.
for (unsigned i = 0; i != numNonSelfParams; ++i) {
auto ty = params[i].getParameterType();
auto eltPattern = origType.getFunctionParamType(i);
auto flags = params[i].getParameterFlags();
bool forSelf = false;

// If we have an inline operator, when it was imported, it was turned
// from a method into a static function. So, we need to shift over the
// params by one and use "self" as the first param's type.
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@gribozavr gribozavr Jul 20, 2020 •
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I can't say what the right fix should be exactly, but I feel like this code is working around the problem more than solving it directly. Resetting NextOrigParamIndex does not feel right to me (so this code won't work for argument count greater than 2, I think?) Abstraction pattern and the code to handle self in this converter class are supposed to abstract away this issue, I think. Currently they handle the abstraction in the opposite direction (importing a C free function as a Swift method). Here, we have the opposite problem -- importing a C++ member function as a Swift static method.

WDYT about extending this code to skip both the Swift self which was mapped from C, and Swift parameters that correspond to C++ this, and letting the HandleForeignSelf handle them at the appropriate point?

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WDYT about extending this code to skip both the Swift self which was mapped from C, and Swift parameters that correspond to C++ this, and letting the HandleForeignSelf handle them at the appropriate point?

The issue is CXXMethodConventions creates a CFunctionTypeConventions object with the function type T(T) when it should be T(T, T). This means that there are the wrong number of arguments. I think we have two choices, either we can pass forSelf=true for the first argument, then decrement NextOrigParamIndex (still a bit of a hack but also less bad than what's currently in this PR), or we can pass a more "correct" type to CFunctionTypeConventions. WDYT would be better?

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I've updated this PR to use the first solution I suggested but I can change it to use the second if you'd rather.

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@hlopko @varungandhi-apple thoughts on the above conversation? I'd like to get this patch moving :)

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@gribozavr @hlopko ping. Once re-reviewed I'll rebase.

if (isCxxOperator) {
if (i == 0)
forSelf = true;
else if (i == 1)
NextOrigParamIndex--;
}

visit(flags.getValueOwnership(), /*forSelf=*/false, eltPattern, ty,
visit(flags.getValueOwnership(), forSelf, eltPattern, ty,
flags.isNoDerivative());
}

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10 changes: 10 additions & 0 deletions test/Interop/Cxx/operators/Inputs/member-inline.h
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Expand Up @@ -12,4 +12,14 @@ struct HasDeletedOperator {
void operator!=(HasDeletedOperator) const = delete;
};

struct AddressOnlyIntWrapper {
int value;
AddressOnlyIntWrapper(int value) : value(value) {}
AddressOnlyIntWrapper(AddressOnlyIntWrapper const &other)
: value(other.value) {}
AddressOnlyIntWrapper operator-(AddressOnlyIntWrapper rhs) {
return AddressOnlyIntWrapper(value - rhs.value);
}
};

#endif
11 changes: 9 additions & 2 deletions test/Interop/Cxx/operators/member-inline-irgen.swift
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Expand Up @@ -5,7 +5,14 @@

import MemberInline

public func sub(_ lhs: inout LoadableIntWrapper, _ rhs: LoadableIntWrapper) -> LoadableIntWrapper { lhs - rhs }

// CHECK: call [[RES:i32|i64]] [[NAME:@(_ZN18LoadableIntWrappermiES_|"\?\?GLoadableIntWrapper@@QEAA\?AU0@U0@@Z")]](%struct.LoadableIntWrapper* {{%[0-9]+}}, {{i32|\[1 x i32\]|i64|%struct.LoadableIntWrapper\* byval align 4}} {{%[0-9]+}})

// CHECK: define linkonce_odr [[RES]] [[NAME]](%struct.LoadableIntWrapper* %this, {{i32 %rhs.coerce|\[1 x i32\] %rhs.coerce|i64 %rhs.coerce|%struct.LoadableIntWrapper\* byval\(%struct.LoadableIntWrapper\) align 4 %rhs}})
public func sub(_ lhs: inout LoadableIntWrapper, _ rhs: LoadableIntWrapper) -> LoadableIntWrapper { lhs - rhs }

// CHECK-LABEL: define {{.*}}void @"$s4main24subAddressOnlyIntWrapperySo0cdeF0VADz_ADtF"
// CHECK: call void [[NAME:@(_ZN21AddressOnlyIntWrappermiES_|"\?\?GAddressOnlyIntWrapper@@QEAA\?AU0@U0@@Z")]](%struct.AddressOnlyIntWrapper* {{%[0-9]+}}, %struct.AddressOnlyIntWrapper* {{%[0-9]+}}, %struct.AddressOnlyIntWrapper* {{%[0-9]+}})
// CHECK: ret void

// CHECK: define linkonce_odr void [[NAME]](%struct.AddressOnlyIntWrapper* {{.*}}%agg.result, %struct.AddressOnlyIntWrapper* %this, %struct.AddressOnlyIntWrapper* %rhs)
public func subAddressOnlyIntWrapper(_ lhs: inout AddressOnlyIntWrapper, _ rhs: AddressOnlyIntWrapper) -> AddressOnlyIntWrapper { lhs - rhs }
4 changes: 4 additions & 0 deletions test/Interop/Cxx/operators/member-inline-module-interface.swift
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Expand Up @@ -6,3 +6,7 @@

// CHECK: struct HasDeletedOperator {
// CHECK: }

// CHECK: struct AddressOnlyIntWrapper {
// CHECK: static func - (lhs: inout AddressOnlyIntWrapper, rhs: AddressOnlyIntWrapper) -> AddressOnlyIntWrapper
// CHECK: }
14 changes: 14 additions & 0 deletions test/Interop/Cxx/operators/member-inline-silgen.swift
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Expand Up @@ -12,3 +12,17 @@ public func sub(_ lhs: inout LoadableIntWrapper, _ rhs: LoadableIntWrapper) -> L
// CHECK: end_access [[SELFACCESS]] : $*LoadableIntWrapper

// CHECK: sil [clang LoadableIntWrapper."-"] [[NAME]] : $@convention(c) (@inout LoadableIntWrapper, LoadableIntWrapper) -> LoadableIntWrapper

// CHECK-LABEL: sil @$s4main24subAddressOnlyIntWrapperySo0cdeF0VADz_ADtF : $@convention(thin) (@inout AddressOnlyIntWrapper, @in_guaranteed AddressOnlyIntWrapper) -> @out AddressOnlyIntWrapper
// CHECK: bb0([[OUT:%.*]] : $*AddressOnlyIntWrapper, [[LHS:%.*]] : $*AddressOnlyIntWrapper, [[RHS:%.*]] : $*AddressOnlyIntWrapper):
// CHECK: [[RHS_TMP:%.*]] = alloc_stack $AddressOnlyIntWrapper
// CHECK: copy_addr [[RHS]] to [initialization] [[RHS_TMP]] : $*AddressOnlyIntWrapper
// CHECK: [[LHS_ACCESS:%.*]] = begin_access [modify] [static] [[LHS]] : $*AddressOnlyIntWrapper
// CHECK: [[FN:%.*]] = function_ref [[NAME:@(_ZN21AddressOnlyIntWrappermiES_|\?\?GAddressOnlyIntWrapper@@QEAA\?AU0@U0@@Z)]] : $@convention(c) (@inout AddressOnlyIntWrapper, @in AddressOnlyIntWrapper) -> @out AddressOnlyIntWrapper
// CHECK: apply [[FN]]([[OUT]], [[LHS_ACCESS]], [[RHS_TMP]]) : $@convention(c) (@inout AddressOnlyIntWrapper, @in AddressOnlyIntWrapper) -> @out AddressOnlyIntWrapper
// CHECK: end_access [[LHS_ACCESS]]
// CHECK: dealloc_stack [[RHS_TMP]]
// CHECK: end sil function '$s4main24subAddressOnlyIntWrapperySo0cdeF0VADz_ADtF'

// CHECK: sil [clang AddressOnlyIntWrapper."-"] [[NAME]] : $@convention(c) (@inout AddressOnlyIntWrapper, @in AddressOnlyIntWrapper) -> @out AddressOnlyIntWrapper
public func subAddressOnlyIntWrapper(_ lhs: inout AddressOnlyIntWrapper, _ rhs: AddressOnlyIntWrapper) -> AddressOnlyIntWrapper { lhs - rhs }
5 changes: 4 additions & 1 deletion test/Interop/Cxx/operators/member-inline-typechecker.swift
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Expand Up @@ -4,5 +4,8 @@ import MemberInline

var lhs = LoadableIntWrapper(value: 42)
let rhs = LoadableIntWrapper(value: 23)
let resultMinus = lhs - rhs

let resultPlus = lhs - rhs
var lhsAddressOnly = AddressOnlyIntWrapper(42)
var rhsAddressOnly = AddressOnlyIntWrapper(23)
let resultMinusAddressOnly = lhsAddressOnly - rhsAddressOnly
8 changes: 8 additions & 0 deletions test/Interop/Cxx/operators/member-inline.swift
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Expand Up @@ -19,4 +19,12 @@ OperatorsTestSuite.test("LoadableIntWrapper.plus") {
expectEqual(19, result.value)
}

OperatorsTestSuite.test("AddressOnlyIntWrapper.plus") {
var lhs = AddressOnlyIntWrapper(42)
let rhs = AddressOnlyIntWrapper(23)

let result = lhs - rhs
expectEqual(19, result.value)
}

runAllTests()