[all-commits] [llvm/llvm-project] 6c75ab: Introduce _BitInt, deprecate _ExtInt

[Aaron Ballman via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6c75ab5f66b403f7ca67e86aeed3a58abe10570b
      https://github.com/llvm/llvm-project/commit/6c75ab5f66b403f7ca67e86aeed3a58abe10570b
  Author: Aaron Ballman <aaron at aaronballman.com>
  Date:   2021-12-06 (Mon, 06 Dec 2021)

  Changed paths:
    M clang-tools-extra/test/clang-tidy/checkers/bugprone-implicit-widening-of-multiplication-result-extint.cpp
    M clang/docs/LanguageExtensions.rst
    M clang/docs/ReleaseNotes.rst
    M clang/include/clang/AST/ASTContext.h
    M clang/include/clang/AST/RecursiveASTVisitor.h
    M clang/include/clang/AST/Type.h
    M clang/include/clang/AST/TypeLoc.h
    M clang/include/clang/AST/TypeProperties.td
    M clang/include/clang/Basic/DiagnosticGroups.td
    M clang/include/clang/Basic/DiagnosticParseKinds.td
    M clang/include/clang/Basic/DiagnosticSemaKinds.td
    M clang/include/clang/Basic/Specifiers.h
    M clang/include/clang/Basic/TargetInfo.h
    M clang/include/clang/Basic/TokenKinds.def
    M clang/include/clang/Basic/TypeNodes.td
    M clang/include/clang/Parse/Parser.h
    M clang/include/clang/Sema/DeclSpec.h
    M clang/include/clang/Sema/Sema.h
    M clang/include/clang/Serialization/TypeBitCodes.def
    M clang/lib/AST/ASTContext.cpp
    M clang/lib/AST/ASTStructuralEquivalence.cpp
    M clang/lib/AST/ExprConstant.cpp
    M clang/lib/AST/ItaniumMangle.cpp
    M clang/lib/AST/MicrosoftMangle.cpp
    M clang/lib/AST/Type.cpp
    M clang/lib/AST/TypePrinter.cpp
    M clang/lib/Basic/Targets/AArch64.h
    M clang/lib/Basic/Targets/AMDGPU.h
    M clang/lib/Basic/Targets/ARC.h
    M clang/lib/Basic/Targets/ARM.h
    M clang/lib/Basic/Targets/Hexagon.h
    M clang/lib/Basic/Targets/Lanai.h
    M clang/lib/Basic/Targets/Mips.h
    M clang/lib/Basic/Targets/NVPTX.h
    M clang/lib/Basic/Targets/PNaCl.h
    M clang/lib/Basic/Targets/PPC.h
    M clang/lib/Basic/Targets/RISCV.h
    M clang/lib/Basic/Targets/SPIR.h
    M clang/lib/Basic/Targets/Sparc.h
    M clang/lib/Basic/Targets/SystemZ.h
    M clang/lib/Basic/Targets/WebAssembly.h
    M clang/lib/Basic/Targets/X86.h
    M clang/lib/Basic/Targets/XCore.h
    M clang/lib/CodeGen/ABIInfo.h
    M clang/lib/CodeGen/CGBuiltin.cpp
    M clang/lib/CodeGen/CGCall.cpp
    M clang/lib/CodeGen/CGDebugInfo.cpp
    M clang/lib/CodeGen/CGDebugInfo.h
    M clang/lib/CodeGen/CodeGenFunction.cpp
    M clang/lib/CodeGen/CodeGenTBAA.cpp
    M clang/lib/CodeGen/CodeGenTypes.cpp
    M clang/lib/CodeGen/ItaniumCXXABI.cpp
    M clang/lib/CodeGen/TargetInfo.cpp
    M clang/lib/Parse/ParseDecl.cpp
    M clang/lib/Parse/ParseExpr.cpp
    M clang/lib/Parse/ParseExprCXX.cpp
    M clang/lib/Parse/ParseTentative.cpp
    M clang/lib/Sema/DeclSpec.cpp
    M clang/lib/Sema/Sema.cpp
    M clang/lib/Sema/SemaChecking.cpp
    M clang/lib/Sema/SemaDecl.cpp
    M clang/lib/Sema/SemaDeclAttr.cpp
    M clang/lib/Sema/SemaExpr.cpp
    M clang/lib/Sema/SemaLookup.cpp
    M clang/lib/Sema/SemaStmtAsm.cpp
    M clang/lib/Sema/SemaTemplate.cpp
    M clang/lib/Sema/SemaTemplateDeduction.cpp
    M clang/lib/Sema/SemaTemplateVariadic.cpp
    M clang/lib/Sema/SemaType.cpp
    M clang/lib/Sema/TreeTransform.h
    M clang/lib/Serialization/ASTReader.cpp
    M clang/lib/Serialization/ASTWriter.cpp
    M clang/test/CXX/temp/temp.param/p7.cpp
    M clang/test/CodeGen/attr-noundef.cpp
    M clang/test/CodeGen/builtins-overflow.c
    M clang/test/CodeGen/ext-int-cc.c
    M clang/test/CodeGen/ext-int-sanitizer.cpp
    M clang/test/CodeGen/ext-int.c
    M clang/test/CodeGen/extend-arg-64.c
    M clang/test/CodeGenCXX/ext-int.cpp
    M clang/test/CodeGenOpenCL/ext-int-shift.cl
    M clang/test/OpenMP/nvptx_unsupported_type_messages.cpp
    M clang/test/Parser/ext-int.cpp
    M clang/test/Sema/builtins-overflow.c
    M clang/test/Sema/builtins.c
    M clang/test/Sema/ext-int.c
    M clang/test/Sema/invalid-bitwidth-expr.mm
    M clang/test/SemaCXX/ext-int-asm.cpp
    M clang/test/SemaCXX/ext-int.cpp
    M clang/tools/libclang/CIndex.cpp

  Log Message:
  -----------
  Introduce _BitInt, deprecate _ExtInt

WG14 adopted the _ExtInt feature from Clang for C23, but renamed the
type to be _BitInt. This patch does the vast majority of the work to
rename _ExtInt to _BitInt, which accounts for most of its size. The new
type is exposed in older C modes and all C++ modes as a conforming
extension. However, there are functional changes worth calling out:

* Deprecates _ExtInt with a fix-it to help users migrate to _BitInt.
* Updates the mangling for the type.
* Updates the documentation and adds a release note to warn users what
is going on.
* Adds new diagnostics for use of _BitInt to call out when it's used as
a Clang extension or as a pre-C23 compatibility concern.
* Adds new tests for the new diagnostic behaviors.

I want to call out the ABI break specifically. We do not believe that
this break will cause a significant imposition for early adopters of
the feature, and so this is being done as a full break. If it turns out
there are critical uses where recompilation is not an option for some
reason, we can consider using ABI tags to ease the transition.