From 90ec6dff860f4ec9cb89041b6e2a671cc3ce8f47 Mon Sep 17 00:00:00 2001 From: Nikita Popov Date: Sat, 4 Sep 2021 12:18:52 +0200 Subject: [OpaquePtr] Forbid mixing typed and opaque pointers Currently, opaque pointers are supported in two forms: The -force-opaque-pointers mode, where all pointers are opaque and typed pointers do not exist. And as a simple ptr type that can coexist with typed pointers. This patch removes support for the mixed mode. You either get typed pointers, or you get opaque pointers, but not both. In the (current) default mode, using ptr is forbidden. In -opaque-pointers mode, all pointers are opaque. The motivation here is that the mixed mode introduces additional issues that don't exist in fully opaque mode. D105155 is an example of a design problem. Looking at D109259, it would probably need additional work to support mixed mode (e.g. to generate GEPs for typed base but opaque result). Mixed mode will also end up inserting many casts between i8* and ptr, which would require significant additional work to consistently avoid. I don't think the mixed mode is particularly valuable, as it doesn't align with our end goal. The only thing I've found it to be moderately useful for is adding some opaque pointer tests in between typed pointer tests, but I think we can live without that. Differential Revision: https://reviews.llvm.org/D109290 --- llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 3 +++ 1 file changed, 3 insertions(+) (limited to 'llvm/lib/Bitcode/Reader/BitcodeReader.cpp') diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp index 543cb9a..6aad83e 100644 --- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp +++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp @@ -1792,6 +1792,9 @@ Error BitcodeReader::parseTypeTableBody() { case bitc::TYPE_CODE_OPAQUE_POINTER: { // OPAQUE_POINTER: [addrspace] if (Record.size() != 1) return error("Invalid record"); + if (Context.supportsTypedPointers()) + return error( + "Opaque pointers are only supported in -opaque-pointers mode"); unsigned AddressSpace = Record[0]; ResultTy = PointerType::get(Context, AddressSpace); break; -- cgit v1.1