[PATCH] D112113: [ObjC] type method metadata `_imp`, messenger routine at callsite with program address space

[Matt Jacobson via Phabricator via cfe-commits]

mhjacobson created this revision.
mhjacobson added reviewers: rjmccall, ddunbar.
Herald added subscribers: pengfei, Jim, dylanmckay.
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On targets with non-default program address space (e.g., Harvard architectures), clang crashes (example backtrace below) when emitting Objective-C method metadata, because the address of the method IMP cannot be bitcast to `i8*`.  It similarly crashes at messenger callsite with a failed bitcast.

Define the `_imp` field instead as `i8 addrspace(1)*` (or whatever the target's program address space is).  And in `getMessageSendInfo()`, create `signatureType` by specifying the program address space.

Add a regression test using the AVR target.  Test failed previously and passes now.  Checked codegen of the test for x86_64-apple-darwin19.6.0 and saw no difference, as expected.

Backtrace (when emitting method metadata):

  Assertion failed: (CastInst::castIsValid(Instruction::BitCast, C, DstTy) && "Invalid constantexpr bitcast!"), function getBitCast, file /Users/matt/src/llvm/llvm/lib/IR/Constants.cpp, line 2224.
  
  ...
  
  7  libsystem_c.dylib        0x00007fff6ec09ac6 err + 0
  8  clang-14                 0x0000000101800518 llvm::ConstantExpr::getBitCast(llvm::Constant*, llvm::Type*, bool) + 120
  9  clang-14                 0x000000010394ca70 clang::CodeGen::ConstantAggregateBuilderBase::addBitCast(llvm::Constant*, llvm::Type*) + 48
  10 clang-14                 0x0000000103999ac2 (anonymous namespace)::CGObjCNonFragileABIMac::emitMethodConstant(clang::CodeGen::ConstantArrayBuilder&, clang::ObjCMethodDecl const*, bool) + 402
  11 clang-14                 0x0000000103999102 (anonymous namespace)::CGObjCNonFragileABIMac::emitMethodList(llvm::Twine, (anonymous namespace)::(anonymous namespace)::MethodListType, llvm::ArrayRef<clang::ObjCMethodDecl const*>) + 1074
  12 clang-14                 0x000000010399a4c0 (anonymous namespace)::CGObjCNonFragileABIMac::BuildClassRoTInitializer(unsigned int, unsigned int, unsigned int, clang::ObjCImplementationDecl const*) + 1376
  13 clang-14                 0x0000000103990b9b (anonymous namespace)::CGObjCNonFragileABIMac::GenerateClass(clang::ObjCImplementationDecl const*) + 1995
  14 clang-14                 0x0000000103bb87d1 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) + 2065
  15 clang-14                 0x0000000103db5bf2 (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) + 146
  16 clang-14                 0x0000000103b61014 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) + 228
  17 clang-14                 0x00000001070d7425 clang::ParseAST(clang::Sema&, bool, bool) + 533


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D112113

Files:
  clang/lib/CodeGen/CGObjCMac.cpp
  clang/lib/CodeGen/CGObjCRuntime.cpp
  clang/test/CodeGen/avr/objc-method.m

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