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[IRGen] Make sure a C++ constructor thunk is called when it's needed #71790

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Merged
merged 2 commits into from
Feb 22, 2024
Merged

[IRGen] Make sure a C++ constructor thunk is called when it's needed #71790

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5066de8
[IRGen] Make sure a C++ constructor thunk is called when it's needed
ahatanaka Feb 21, 2024
2cbf391
Add missing FileCheck prefix
ahatanaka Feb 22, 2024
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19 changes: 14 additions & 5 deletions lib/IRGen/GenDecl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3466,6 +3466,10 @@ llvm::Constant *swift::irgen::emitCXXConstructorThunkIfNeeded(
return ctorAddress;
}

// Check whether we've created the thunk already.
if (auto *thunkFn = IGM.Module.getFunction(name))
return thunkFn;

llvm::Function *thunk = llvm::Function::Create(
assumedFnType, llvm::Function::PrivateLinkage, name, &IGM.Module);

Expand Down Expand Up @@ -3546,10 +3550,15 @@ llvm::Function *IRGenModule::getAddrOfSILFunction(
LinkEntity entity =
LinkEntity::forSILFunction(f, shouldCallPreviousImplementation);

// Check whether we've created the function already.
auto clangDecl = f->getClangDecl();
auto cxxCtor = dyn_cast_or_null<clang::CXXConstructorDecl>(clangDecl);

// Check whether we've created the function already. If the function is a C++
// constructor, don't return the constructor here as a thunk might be needed
// to call the constructor.
// FIXME: We should integrate this into the LinkEntity cache more cleanly.
llvm::Function *fn = Module.getFunction(entity.mangleAsString());
if (fn) {
if (fn && !cxxCtor) {
if (forDefinition) {
updateLinkageForDefinition(*this, fn, entity);
}
Expand All @@ -3561,7 +3570,7 @@ llvm::Function *IRGenModule::getAddrOfSILFunction(
// the insert-before point.
llvm::Constant *clangAddr = nullptr;
bool isObjCDirect = false;
if (auto clangDecl = f->getClangDecl()) {
if (clangDecl) {
// If we have an Objective-C Clang declaration, it must be a direct
// method and we want to generate the IR declaration ourselves.
if (auto objcDecl = dyn_cast<clang::ObjCMethodDecl>(clangDecl)) {
Expand All @@ -3572,7 +3581,7 @@ llvm::Function *IRGenModule::getAddrOfSILFunction(
clangAddr = getAddrOfClangGlobalDecl(globalDecl, forDefinition);
}

if (auto ctor = dyn_cast<clang::CXXConstructorDecl>(clangDecl)) {
if (cxxCtor) {
Signature signature = getSignature(f->getLoweredFunctionType());

// The thunk has private linkage, so it doesn't need to have a predictable
Expand All @@ -3582,7 +3591,7 @@ llvm::Function *IRGenModule::getAddrOfSILFunction(
stream << "__swift_cxx_ctor";
entity.mangle(stream);

clangAddr = emitCXXConstructorThunkIfNeeded(*this, signature, ctor, name,
clangAddr = emitCXXConstructorThunkIfNeeded(*this, signature, cxxCtor, name,
clangAddr);
}
}
Expand Down
7 changes: 5 additions & 2 deletions test/Interop/Cxx/class/constructors-irgen-windows.swift
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Expand Up @@ -9,10 +9,13 @@ import Constructors
import TypeClassification

public func createHasVirtualBase() -> HasVirtualBase {
// MICROSOFT_X64: define dllexport swiftcc void @"$s7MySwift20createHasVirtualBaseSo0{{bcD0VyF|deF0VyF}}"(ptr noalias sret({{.*}}) %0)
// MICROSOFT_X64: define dllexport swiftcc void @"$s7MySwift20createHasVirtualBaseSo0{{bcD0VyF|deF0VyF}}"(ptr noalias sret({{.*}}) [[V0:%.*]])
// MICROSOFT_X64-NOT: define
// Note `this` return type and implicit "most derived" argument.
// MICROSOFT_X64: call ptr @"??0HasVirtualBase@@QEAA@UArgType@@@Z"(ptr %{{[0-9]+}}, i32 %{{[0-9]+}}, i32 1)
// MICROSOFT_X64: [[V1:%.*]] = alloca %{{.*}}, align 8
// MICROSOFT_X64: call ptr @"??0HasVirtualBase@@QEAA@UArgType@@@Z"(ptr [[V1]], i32 %{{[0-9]+}}, i32 1)
// MICROSOFT_X64: call ptr @"??0HasVirtualBase@@QEAA@UArgType@@@Z"(ptr [[V0]], i32 %{{[0-9]+}}, i32 1)
let _ : HasVirtualBase = HasVirtualBase(ArgType())
return HasVirtualBase(ArgType())
}

Expand Down
1 change: 0 additions & 1 deletion test/Interop/Cxx/value-witness-table/custom-destructors-virtual.swift
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Expand Up @@ -6,7 +6,6 @@
// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xcc -fno-rtti -O)
//
// REQUIRES: executable_test
// XFAIL: OS=windows-msvc

import CustomDestructor
import StdlibUnittest
Expand Down