[all-commits] [llvm/llvm-project] 633d1d: [libc++] Use bounded iterators in std::span when t...

[Louis Dionne via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 633d1d0df766d5838c4c0b675fc7ac077159cec6
      https://github.com/llvm/llvm-project/commit/633d1d0df766d5838c4c0b675fc7ac077159cec6
  Author: Louis Dionne <ldionne.2 at gmail.com>
  Date:   2022-06-27 (Mon, 27 Jun 2022)

  Changed paths:
    M libcxx/include/CMakeLists.txt
    M libcxx/include/__config
    A libcxx/include/__iterator/bounded_iter.h
    M libcxx/include/iterator
    M libcxx/include/module.modulemap.in
    M libcxx/include/span
    A libcxx/test/libcxx/containers/views/views.span/debug.iterator-indexing.pass.cpp
    A libcxx/test/libcxx/containers/views/views.span/span.elem/assert.back.pass.cpp
    A libcxx/test/libcxx/containers/views/views.span/span.elem/assert.front.pass.cpp
    A libcxx/test/libcxx/containers/views/views.span/span.elem/assert.op_idx.pass.cpp
    A libcxx/test/libcxx/containers/views/views.span/span.sub/assert.first.pass.cpp
    A libcxx/test/libcxx/containers/views/views.span/span.sub/assert.last.pass.cpp
    A libcxx/test/libcxx/containers/views/views.span/span.sub/assert.subspan.pass.cpp
    A libcxx/test/libcxx/iterators/bounded_iter/arithmetic.pass.cpp
    A libcxx/test/libcxx/iterators/bounded_iter/comparison.pass.cpp
    A libcxx/test/libcxx/iterators/bounded_iter/dereference.pass.cpp
    A libcxx/test/libcxx/iterators/bounded_iter/pointer_traits.pass.cpp
    A libcxx/test/libcxx/iterators/bounded_iter/types.compile.pass.cpp
    M libcxx/test/libcxx/private_headers.verify.cpp
    R libcxx/test/std/containers/views/views.span/span.sub/first.fail.cpp
    A libcxx/test/std/containers/views/views.span/span.sub/first.verify.cpp
    R libcxx/test/std/containers/views/views.span/span.sub/last.fail.cpp
    A libcxx/test/std/containers/views/views.span/span.sub/last.verify.cpp
    R libcxx/test/std/containers/views/views.span/span.sub/subspan.fail.cpp
    A libcxx/test/std/containers/views/views.span/span.sub/subspan.verify.cpp

  Log Message:
  -----------
  [libc++] Use bounded iterators in std::span when the debug mode is enabled

Previously, we'd use raw pointers when the debug mode was enabled,
which means we wouldn't get out-of-range checking with std::span's
iterators.

This patch introduces a new class called __bounded_iter which can
be used to wrap iterators and make them carry around bounds-related
information. This allows iterators to assert when they are dereferenced
outside of their bounds.

As a fly-by change, this commit removes the _LIBCPP_ABI_SPAN_POINTER_ITERATORS
knob. Indeed, not using a raw pointer as the iterator type is useful to
avoid users depending on properties of raw pointers in their code.

This is an alternative to D127401.

Differential Revision: https://reviews.llvm.org/D127418