[Clang][Docs] Simpler syntax for Github links.

Github links in release notes are often invalid rST,
clutter the release notes and are annoying to write.

This introduces a sphynx plugin that rewrites
 `#GH<NUMBER>` to a link to the corresponding issue.

While this could be introduced globally on all of LLVM,
the PR only modifies Clang for now.

clang/docs/ReleaseNotes.rst

@@ -79,7 +79,7 @@ C++20 Feature Support
   more to ease the implementation and improve the user's using experience.
   This follows the MSVC's behavior. Users interested in testing the more strict
   behavior can use the flag '-Xclang -fno-skip-odr-check-in-gmf'.
-  (`#79240 <https://github.com/llvm/llvm-project/issues/79240>`_).
+  (#GH79240).
 
 - Implemented the `__is_layout_compatible` intrinsic to support
   `P0466R5: Layout-compatibility and Pointer-interconvertibility Traits <https://wg21.link/P0466R5>`_.
@@ -116,7 +116,7 @@ C Language Changes
 C23 Feature Support
 ^^^^^^^^^^^^^^^^^^^
 - No longer diagnose use of binary literals as an extension in C23 mode. Fixes
-  `#72017 <https://github.com/llvm/llvm-project/issues/72017>`_.
+  #GH72017.
 
 - Corrected parsing behavior for the ``alignas`` specifier/qualifier in C23. We
   previously handled it as an attribute as in C++, but there are parsing
@@ -129,7 +129,7 @@ C23 Feature Support
      };
      int i alignas(8) /* was accepted, now rejected */ ;
 
-  Fixes (`#81472 <https://github.com/llvm/llvm-project/issues/81472>`_).
+  Fixes (#GH81472).
 
 - Clang now generates predefined macros of the form ``__TYPE_FMTB__`` and
   ``__TYPE_FMTb__`` (e.g., ``__UINT_FAST64_FMTB__``) in C23 mode for use with
@@ -173,7 +173,7 @@ Improvements to Clang's diagnostics
   name specifiers.
 
 - The ``-Wshorten-64-to-32`` diagnostic is now grouped under ``-Wimplicit-int-conversion`` instead
-   of ``-Wconversion``. Fixes `#69444 <https://github.com/llvm/llvm-project/issues/69444>`_.
+   of ``-Wconversion``. Fixes #GH69444.
 
 - Clang now diagnoses friend declarations with an ``enum`` elaborated-type-specifier in language modes after C++98.
 
@@ -186,7 +186,7 @@ Improvements to Clang's diagnostics
   ``unsigned long long``, but this behavior may change in the future when Clang
   implements
   `WG14 N3029 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3029.htm>`_.
-  Fixes `#69352 <https://github.com/llvm/llvm-project/issues/69352>`_.
+  (#GH69352).
 
 - Clang now diagnoses extraneous template parameter lists as a language extension.
 
@@ -200,17 +200,17 @@ Bug Fixes in This Version
 - Clang now accepts elaborated-type-specifiers that explicitly specialize
   a member class template for an implicit instantiation of a class template.
 
-- Fixed missing warnings when doing bool-like conversions in C23 (`#79435 <https://github.com/llvm/llvm-project/issues/79435>`_).
+- Fixed missing warnings when doing bool-like conversions in C23 (#GH79435).
 - Clang's ``-Wshadow`` no longer warns when an init-capture is named the same as
   a class field unless the lambda can capture this.
-  Fixes (`#71976 <https://github.com/llvm/llvm-project/issues/71976>`_)
+  Fixes (#GH71976)
 
 - Clang now accepts qualified partial/explicit specializations of variable templates that
   are not nominable in the lookup context of the specialization.
 
 - Clang now doesn't produce false-positive warning `-Wconstant-logical-operand`
   for logical operators in C23.
-  Fixes (`#64356 <https://github.com/llvm/llvm-project/issues/64356>`_).
+  Fixes (#GH64356).
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -222,65 +222,51 @@ Bug Fixes to C++ Support
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
 - Fix crash when calling the constructor of an invalid class.
-  Fixes (`#10518 <https://github.com/llvm/llvm-project/issues/10518>`_),
-  (`#67914 <https://github.com/llvm/llvm-project/issues/10518>`_),
-  and (`#78388 <https://github.com/llvm/llvm-project/issues/78388>`_)
+  (#GH10518) (#GH67914) (#GH78388)
 - Fix crash when using lifetimebound attribute in function with trailing return.
-  Fixes (`#73619 <https://github.com/llvm/llvm-project/issues/73619>`_)
+  (#GH73619)
 - Addressed an issue where constraints involving injected class types are perceived
-  distinct from its specialization types.
-  (`#56482 <https://github.com/llvm/llvm-project/issues/56482>`_)
+  distinct from its specialization types. (#GH56482)
 - Fixed a bug where variables referenced by requires-clauses inside
-  nested generic lambdas were not properly injected into the constraint scope.
-  (`#73418 <https://github.com/llvm/llvm-project/issues/73418>`_)
+  nested generic lambdas were not properly injected into the constraint scope. (#GH73418)
 - Fixed a crash where substituting into a requires-expression that refers to function
   parameters during the equivalence determination of two constraint expressions.
-  (`#74447 <https://github.com/llvm/llvm-project/issues/74447>`_)
+  (#GH74447)
 - Fixed deducing auto& from const int in template parameters of partial
-  specializations.
-  (`#77189 <https://github.com/llvm/llvm-project/issues/77189>`_)
+  specializations. (#GH77189)
 - Fix for crash when using a erroneous type in a return statement.
-  Fixes (`#63244 <https://github.com/llvm/llvm-project/issues/63244>`_)
-  and (`#79745 <https://github.com/llvm/llvm-project/issues/79745>`_)
+  (#GH63244) (#GH79745)
 - Fixed an out-of-bounds error caused by building a recovery expression for ill-formed
-  function calls while substituting into constraints.
-  (`#58548 <https://github.com/llvm/llvm-project/issues/58548>`_)
-- Fix incorrect code generation caused by the object argument of ``static operator()`` and ``static operator[]`` calls not being evaluated.
-  Fixes (`#67976 <https://github.com/llvm/llvm-project/issues/67976>`_)
+  function calls while substituting into constraints. (#GH58548)
+- Fix incorrect code generation caused by the object argument
+  of ``static operator()`` and ``static operator[]`` calls not being evaluated. (#GH67976)
 - Fix crash and diagnostic with const qualified member operator new.
-  Fixes (`#79748 <https://github.com/llvm/llvm-project/issues/79748>`_)
+  Fixes (#GH79748)
 - Fixed a crash where substituting into a requires-expression that involves parameter packs
-  during the equivalence determination of two constraint expressions.
-  (`#72557 <https://github.com/llvm/llvm-project/issues/72557>`_)
+  during the equivalence determination of two constraint expressions. (#GH72557)
 - Fix a crash when specializing an out-of-line member function with a default
   parameter where we did an incorrect specialization of the initialization of
-  the default parameter.
-  Fixes (`#68490 <https://github.com/llvm/llvm-project/issues/68490>`_)
+  the default parameter. (#GH68490)
 - Fix a crash when trying to call a varargs function that also has an explicit object parameter.
-  Fixes (`#80971 ICE when explicit object parameter be a function parameter pack`)
-- Reject explicit object parameters on `new` and `delete` operators.
-  Fixes (`#82249 <https://github.com/llvm/llvm-project/issues/82249>` _)
+  Fixes (#GH80971)
+- Reject explicit object parameters on `new` and `delete` operators. (#GH82249)
+- Fix a crash when trying to call a varargs function that also has an explicit object parameter. (#GH80971)
 - Fixed a bug where abbreviated function templates would append their invented template parameters to
   an empty template parameter lists.
 - Clang now classifies aggregate initialization in C++17 and newer as constant
   or non-constant more accurately. Previously, only a subset of the initializer
-  elements were considered, misclassifying some initializers as constant. Fixes
-  some of (`#80510 <https://github.com/llvm/llvm-project/issues/80510>`).
-- Clang now ignores top-level cv-qualifiers on function parameters in template partial orderings.
-  (`#75404 <https://github.com/llvm/llvm-project/issues/75404>`_)
+  elements were considered, misclassifying some initializers as constant. Partially fixes
+  #GH80510.
+- Clang now ignores top-level cv-qualifiers on function parameters in template partial orderings. (#GH75404)
 - No longer reject valid use of the ``_Alignas`` specifier when declaring a
   local variable, which is supported as a C11 extension in C++. Previously, it
   was only accepted at namespace scope but not at local function scope.
-- Clang no longer tries to call consteval constructors at runtime when they appear in a member initializer.
-  (`#82154 <https://github.com/llvm/llvm-project/issues/82154>`_`)
-- Fix crash when using an immediate-escalated function at global scope.
-  (`#82258 <https://github.com/llvm/llvm-project/issues/82258>`_)
-- Correctly immediate-escalate lambda conversion functions.
-  (`#82258 <https://github.com/llvm/llvm-project/issues/82258>`_)
+- Clang no longer tries to call consteval constructors at runtime when they appear in a member initializer. (#GH82154)
+- Fix crash when using an immediate-escalated function at global scope. (#GH82258)
+- Correctly immediate-escalate lambda conversion functions. (#GH82258)
 - Fixed an issue where template parameters of a nested abbreviated generic lambda within
   a requires-clause lie at the same depth as those of the surrounding lambda. This,
-  in turn, results in the wrong template argument substitution during constraint checking.
-  (`#78524 <https://github.com/llvm/llvm-project/issues/78524>`_)
+  in turn, results in the wrong template argument substitution during constraint checking. (#GH78524)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/docs/conf.py

@@ -18,7 +18,7 @@
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
-# sys.path.insert(0, os.path.abspath('.'))
+sys.path.insert(0, os.path.abspath("."))
 
 # -- General configuration -----------------------------------------------------
 
@@ -27,7 +27,7 @@
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ["sphinx.ext.todo", "sphinx.ext.mathjax", "sphinx.ext.graphviz"]
+extensions = ["sphinx.ext.todo", "sphinx.ext.mathjax", "sphinx.ext.graphviz", "ghlinks"]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ["_templates"]

clang/docs/ghlinks.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+
+from sphinx.application import Sphinx
+import re
+
+__version__ = "1.0"
+
+
+def subst_gh_links(app: Sphinx, docname, source):
+    regex = re.compile("#GH([0-9]+)")
+    out_pattern = r"`#\1 <https://github.com/llvm/llvm-project/issues/\1>`_"
+    result = source[0]
+    result = regex.sub(out_pattern, result)
+    source[0] = result
+
+
+def setup(app: Sphinx):
+    app.connect("source-read", subst_gh_links)
+    return dict(version=__version__, parallel_read_safe=True, parallel_write_safe=True)