[libcxx-commits] [PATCH] D127418: [libc++] Use bounded iterators in std::span when the debug mode is enabled

[Louis Dionne via Phabricator via libcxx-commits]

ldionne created this revision.
Herald added subscribers: arphaman, mgorny.
Herald added a project: All.
ldionne requested review of this revision.
Herald added a project: libc++.
Herald added a subscriber: libcxx-commits.
Herald added a reviewer: libc++.

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 <https://reviews.llvm.org/D127401>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D127418

Files:
  libcxx/include/CMakeLists.txt
  libcxx/include/__config
  libcxx/include/__iterator/bounded_iter.h
  libcxx/include/iterator
  libcxx/include/span
  libcxx/test/libcxx/containers/views/views.span/debug.iterator-indexing.pass.cpp
  libcxx/test/libcxx/containers/views/views.span/span.elem/assert.back.pass.cpp
  libcxx/test/libcxx/containers/views/views.span/span.elem/assert.front.pass.cpp
  libcxx/test/libcxx/containers/views/views.span/span.elem/assert.op_idx.pass.cpp
  libcxx/test/libcxx/containers/views/views.span/span.sub/assert.first.pass.cpp
  libcxx/test/libcxx/containers/views/views.span/span.sub/assert.last.pass.cpp
  libcxx/test/libcxx/containers/views/views.span/span.sub/assert.subspan.pass.cpp
  libcxx/test/libcxx/private_headers.verify.cpp
  libcxx/test/std/containers/views/views.span/span.sub/first.fail.cpp
  libcxx/test/std/containers/views/views.span/span.sub/first.verify.cpp
  libcxx/test/std/containers/views/views.span/span.sub/last.fail.cpp
  libcxx/test/std/containers/views/views.span/span.sub/last.verify.cpp
  libcxx/test/std/containers/views/views.span/span.sub/subspan.fail.cpp
  libcxx/test/std/containers/views/views.span/span.sub/subspan.verify.cpp

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