Add clang format file

.clang-format

@@ -0,0 +1,70 @@
+---
+Language:        Cpp
+BasedOnStyle:  LLVM
+
+# Indentation
+IndentWidth: 4                    # 4 spaces per indent
+AccessModifierOffset: -4
+IndentAccessModifiers: false      # Align access modifiers to braces
+NamespaceIndentation: Inner       # Indent namspace contents
+
+# Comments which match this regex will be unformatted (and therefore can be longer or have more whitespace than other comments)
+CommentPragmas: '^\*\*'
+
+
+# Alignment
+AlignConsecutiveAssignments:
+  Enabled:          true
+  AcrossEmptyLines: false
+  AcrossComments:   true
+  AlignCompound:    true
+  PadOperators:     true
+AlignConsecutiveBitFields:
+  Enabled:          true
+  AcrossEmptyLines: false
+  AcrossComments:   true
+AlignConsecutiveDeclarations:
+  Enabled:          true
+  AcrossEmptyLines: false
+  AcrossComments:   true
+  # For future versions of clang-format
+  # AlignFunctionDeclarations: false
+  # AlignFunctionPointers: false
+AlignConsecutiveMacros:
+  Enabled:          true
+  AcrossEmptyLines: false
+  AcrossComments:   true
+
+# Newlines
+ColumnLimit:     120
+BreakBeforeBraces: Allman         # Braces on their own lines
+SeparateDefinitionBlocks: Always  # Separate definitions (functions etc.) with an empty line
+AlwaysBreakTemplateDeclarations: true # Put template on their own lines
+AllowShortBlocksOnASingleLine: Never
+# On a newer version of clang-format, replace with BinPackArguments: OnePerLine
+BinPackArguments: false           # Don't allow multiple function arguments on the same line unless they all fit
+BinPackParameters: false          # Same but for parameters
+PackConstructorInitializers: NextLine
+AllowShortFunctionsOnASingleLine: None
+BreakBeforeBinaryOperators: NonAssignment # Put binary operators after a line break, rather than before
+
+# Spaces
+SpaceBeforeParens: ControlStatementsExceptControlMacros
+SpaceAfterCStyleCast: true
+PointerAlignment: Left
+
+# Includes
+IncludeBlocks: Regroup            # Regroup includes based on config
+IncludeCategories:
+  - Regex:           '(^"|\.hpp)'  # 'local' includes
+    Priority:        3
+    SortPriority:    0
+    CaseSensitive:   false
+  - Regex:           '\/'         # Library includes
+    Priority:        2
+    SortPriority:    0
+    CaseSensitive:   false
+  - Regex:           '.*'         # Everything else
+    Priority:        1
+    SortPriority:    0
+    CaseSensitive:   false

CONTRIBUTING.md

@@ -321,4 +321,14 @@ class Matrix   // No, class is outside GridKit namespace
 {
   // matrix code
 };
+```
+
+## Developer tooling
+
+### Auto-formatting
+
+To help enforce the above code style guidelines, we use autoformatting provided by [`clang-format`](https://clang.llvm.org/docs/ClangFormat.html), which is distributed as a part of `clang` and `llvm`. Pull-requests must be formatted using the version of `clang-format` distributed by the version of `llvm` required by development with Enzyme.
+
+VS Code users can use `clang-format` to automatically format their code by installing the [C/C++ Extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools) and using the `Format Document` command in the command palette with the file to be formatted open. As well, you can enabled the `editor.formatOnSave` option to auto-format any file when you save it.
 
+Other users can use the [`git clang-format`](https://clang.llvm.org/docs/ClangFormat.html#git-integration) subcommand installed along with `clang-format` to auto-format all staged files.

README.md

@@ -24,6 +24,9 @@ You should have all of the following installed before installing GridKit™
 - [CMake](https://cmake.org/) >= 3.12
 - C++ 17 compliant compiler
 
+#### Developer Dependencies
+- `clang-format`, which can be obtained through most linux distribution package managers, or through the [LLVM project](https://github.com/llvm/llvm-project) >= 15.0.0
+
 ### Installing
 
 GridKit™ uses CMake for build configuration. Per CMake best practices it is recommended