Add cxx_virtual_method instruction. #26658
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Hmm. I'm sad that we need |
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Hi @jrose-apple, the context for needing cxx_virtual_method is here: https://forums.swift.org/t/c-interop-virtual-function-calls/27567/3 in case you missed it. |
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I guess if we have a C++ abstraction pattern we can have a |
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I'm just a simple bystander, but could you add some SILGen tests as well? |
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| : public UnaryInstructionBase<SILInstructionKind::CXXVirtualMethodInst, | ||
| MultipleValueInstruction>, | ||
| public MultipleValueInstructionTrailingObjects<CXXVirtualMethodInst, | ||
| CXXVirtualMethodResult> { |
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I wonder if there's a better way to have exactly two results than this. My SIL isn't strong enough. @gottesmm?
| expansion.ForeignInfo.ClangInfo = | ||
| &clang::CodeGen::arrangeCXXMethodDeclaration(IGM.getClangCGM(), decl); | ||
| llvm::FunctionType *Ty = clang::CodeGen::getFunctionType( | ||
| IGM.getClangCGM(), *expansion.ForeignInfo.ClangInfo); |
| SGF.B.createObjCMethod(Loc, borrowedSelf->getValue(), *constant, | ||
| SILType::getPrimitiveObjectType(methodTy)); | ||
| } else { | ||
| // TODO: Update borrowedSelf with the updated self-pointer... |
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When you do get to it, we'll need some way to indicate that the adjusted "this" pointer depends on the lifetime of the original object. I'm not sure if there's a way to do that other than the mark_dependence instruction, but there ought to be.
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My suggestion (going back to what I was saying above) is that the method should take self either forwarding or guaranteed.
lib/SIL/SILInstructions.cpp
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| : UnaryInstructionBase(DebugLoc, Operand), | ||
| MultipleValueInstructionTrailingObjects( | ||
| this, {Ty, Operand->getType()}, | ||
| {ValueOwnershipKind::Unowned, ValueOwnershipKind::Any}), |
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This is the wrong semantics. The right semantics IMO are that this should be either forwarding or guaranteed.
| SGF.B.createObjCMethod(Loc, borrowedSelf->getValue(), *constant, | ||
| SILType::getPrimitiveObjectType(methodTy)); | ||
| } else { | ||
| // TODO: Update borrowedSelf with the updated self-pointer... |
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My suggestion (going back to what I was saying above) is that the method should take self either forwarding or guaranteed.
This also contains the code to trigger forming cxx_virtual_method instructions but the this pointer adjustment is not hooked up yet.
Companion pr: apple/swift-clang#349