[all-commits] [llvm/llvm-project] 2155dc: [IR] Introduce the opaque pointer type

[aeubanks via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 2155dc51d700c9fb5f29d79eaacf5e1470e4d8ca
      https://github.com/llvm/llvm-project/commit/2155dc51d700c9fb5f29d79eaacf5e1470e4d8ca
  Author: Arthur Eubanks <aeubanks at google.com>
  Date:   2021-05-13 (Thu, 13 May 2021)

  Changed paths:
    M llvm/docs/LangRef.rst
    M llvm/docs/ReleaseNotes.rst
    M llvm/include/llvm/Bitcode/LLVMBitCodes.h
    M llvm/include/llvm/IR/DerivedTypes.h
    M llvm/lib/AsmParser/LLLexer.cpp
    M llvm/lib/AsmParser/LLParser.cpp
    M llvm/lib/Bitcode/Reader/BitcodeReader.cpp
    M llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
    M llvm/lib/IR/AsmWriter.cpp
    M llvm/lib/IR/LLVMContextImpl.h
    M llvm/lib/IR/Type.cpp
    A llvm/test/Assembler/invalid-opaque-ptr.ll
    A llvm/test/Assembler/opaque-ptr.ll

  Log Message:
  -----------
  [IR] Introduce the opaque pointer type

The opaque pointer type is essentially just a normal pointer type with a
null pointee type.

This also adds support for the opaque pointer type to the bitcode
reader/writer, as well as to textual IR.

To avoid confusion with existing pointer types, we disallow creating a
pointer to an opaque pointer.

Opaque pointer types should not be widely used at this point since many
parts of LLVM still do not support them. The next steps are to add some
very simple use cases of opaque pointers to make sure they work, then
start pretending that all pointers are opaque pointers and see what
breaks.

https://lists.llvm.org/pipermail/llvm-dev/2021-May/150359.html

Reviewed By: dblaikie, dexonsmith, pcc

Differential Revision: https://reviews.llvm.org/D101704