Ensure Lightning adheres to C++17 modernization standard with clang-tidy

.github/CHANGELOG.md

@@ -4,6 +4,9 @@
 
 ### Improvements
 
+* PennyLane-Lightning has been updated to conform with clang-tidy recommendations for modernization, offering performance improvements across all use-cases.
+[(#153)](https://github.com/PennyLaneAI/pennylane-lightning/pull/153)
+
 ### Documentation
 
 ### Breaking changes

.github/workflows/format.yml

@@ -1,12 +1,9 @@
 name: Formatting check
 on:
   pull_request:
-    push:
-      branches:
-        - master
-      paths:
-        - "pennylane_lightning/**"
-        - "tests/**"
+  push:
+    branches:
+      - master
 
 jobs:
   black:
@@ -32,6 +29,34 @@ jobs:
       - name: Run Black
         run: black -l 100 pennylane_lightning/ --check
 
+  tidy-cpp:
+    name: Tidy (C++)
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Cancel previous runs
+        uses: styfle/cancel-workflow-action@0.4.1
+        with:
+          access_token: ${{ github.token }}
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+
+      - name: Install dependencies
+        run: sudo apt update && sudo apt -y install clang-tidy-11 python3 cmake g++
+        env:
+          DEBIAN_FRONTEND: noninteractive
+
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Run clang-tidy compilation
+        run: |
+          cmake -BBuild -DENABLE_CLANG_TIDY=on -DCLANG_TIDY_BINARY=clang-tidy-11 .
+          cmake --build ./Build
+
   format-cpp:
     name: Format (C++)
     runs-on: ubuntu-20.04

.github/workflows/tests.yml

@@ -21,6 +21,11 @@ jobs:
         with:
           access_token: ${{ github.token }}
 
+      - uses: actions/setup-python@v2
+        name: Install Python
+        with:
+          python-version: '3.7'
+
       - uses: actions/checkout@v2
 
       - name: Install dependencies
@@ -55,7 +60,6 @@ jobs:
         os: [ubuntu-20.04]
 
     steps:
-
       - name: Checkout PennyLane-Lightning
         uses: actions/checkout@v2
         with:

.github/workflows/wheel_linux_x86_64.yml

@@ -18,6 +18,8 @@ env:
   CIBW_TEST_COMMAND: |
     pl-device-test --device=lightning.qubit --skip-ops -x --tb=short --no-flaky-report
 
+  CIBW_MANYLINUX_X86_64_IMAGE: manylinux2014
+
 jobs:
   linux-wheels-x86-64:
     strategy:

CMakeLists.txt

@@ -29,6 +29,16 @@ endif()
 option(ENABLE_NATIVE "Enable native CPU build tuning" OFF)
 option(BUILD_TESTS "Build cpp tests" OFF)
 option(ENABLE_WARNINGS "Enable warnings" ON)
+option(ENABLE_CLANG_TIDY "Enable clang-tidy build checks" OFF)
+
+if(ENABLE_CLANG_TIDY)
+    if (NOT DEFINED CLANG_TIDY_BINARY)
+        set(CLANG_TIDY_BINARY clang-tidy)
+    endif()
+    set(CMAKE_CXX_CLANG_TIDY ${CLANG_TIDY_BINARY};
+                            -extra-arg=-std=c++17;
+    )
+endif()
 
 # Add pybind11
 include(FetchContent)

pennylane_lightning/src/.clang-tidy

@@ -0,0 +1,232 @@
+---
+Checks:          'clang-diagnostic-*,clang-analyzer-*,-*,-llvmlibc-*,modernize-*,-modernize-use-trailing-return-type,clang-analyzer-cplusplus*,openmp-*,performance-*,portability-*,readability-*'
+WarningsAsErrors: '*'
+HeaderFilterRegex: '.*'
+AnalyzeTemporaryDtors: false
+FormatStyle:     none
+InheritParentConfig: true
+User:            mlxd
+CheckOptions:
+  - key:             modernize-replace-auto-ptr.IncludeStyle
+    value:           llvm
+  - key:             performance-move-const-arg.CheckTriviallyCopyableMove
+    value:           'true'
+  - key:             modernize-use-auto.MinTypeNameLength
+    value:           '5'
+  - key:             readability-static-accessed-through-instance.NameSpecifierNestingThreshold
+    value:           '3'
+  - key:             readability-function-size.VariableThreshold
+    value:           '4294967295'
+  - key:             cert-dcl16-c.NewSuffixes
+    value:           'L;LL;LU;LLU'
+  - key:             readability-identifier-naming.GetConfigPerFile
+    value:           'true'
+  - key:             readability-inconsistent-declaration-parameter-name.Strict
+    value:           'false'
+  - key:             readability-magic-numbers.IgnoredIntegerValues
+    value:           '1;2;3;4;'
+  - key:             modernize-use-default-member-init.UseAssignment
+    value:           'false'
+  - key:             readability-function-size.NestingThreshold
+    value:           '4294967295'
+  - key:             modernize-use-override.AllowOverrideAndFinal
+    value:           'false'
+  - key:             readability-function-size.ParameterThreshold
+    value:           '4294967295'
+  - key:             openmp-exception-escape.IgnoredExceptions
+    value:           ''
+  - key:             modernize-pass-by-value.ValuesOnly
+    value:           'false'
+  - key:             modernize-loop-convert.IncludeStyle
+    value:           llvm
+  - key:             cert-str34-c.DiagnoseSignedUnsignedCharComparisons
+    value:           '0'
+  - key:             readability-identifier-naming.AggressiveDependentMemberLookup
+    value:           'false'
+  - key:             readability-redundant-smartptr-get.IgnoreMacros
+    value:           'true'
+  - key:             modernize-use-emplace.TupleTypes
+    value:           '::std::pair;::std::tuple'
+  - key:             modernize-use-emplace.TupleMakeFunctions
+    value:           '::std::make_pair;::std::make_tuple'
+  - key:             modernize-use-nodiscard.ReplacementString
+    value:           '[[nodiscard]]'
+  - key:             modernize-loop-convert.MakeReverseRangeHeader
+    value:           ''
+  - key:             modernize-replace-random-shuffle.IncludeStyle
+    value:           llvm
+  - key:             modernize-use-bool-literals.IgnoreMacros
+    value:           'true'
+  - key:             google-readability-namespace-comments.ShortNamespaceLines
+    value:           '10'
+  - key:             modernize-avoid-bind.PermissiveParameterList
+    value:           'false'
+  - key:             modernize-use-override.FinalSpelling
+    value:           final
+  - key:             performance-move-constructor-init.IncludeStyle
+    value:           llvm
+  - key:             modernize-loop-convert.UseCxx20ReverseRanges
+    value:           'true'
+  - key:             modernize-use-noexcept.ReplacementString
+    value:           ''
+  - key:             modernize-use-using.IgnoreMacros
+    value:           'true'
+  - key:             performance-type-promotion-in-math-fn.IncludeStyle
+    value:           llvm
+  - key:             modernize-loop-convert.NamingStyle
+    value:           CamelCase
+  - key:             modernize-loop-convert.MakeReverseRangeFunction
+    value:           ''
+  - key:             readability-inconsistent-declaration-parameter-name.IgnoreMacros
+    value:           'true'
+  - key:             performance-no-automatic-move.AllowedTypes
+    value:           ''
+  - key:             performance-for-range-copy.WarnOnAllAutoCopies
+    value:           'false'
+  - key:             readability-identifier-naming.IgnoreFailedSplit
+    value:           'false'
+  - key:             modernize-pass-by-value.IncludeStyle
+    value:           llvm
+  - key:             readability-qualified-auto.AddConstToQualified
+    value:           'true'
+  - key:             readability-simplify-boolean-expr.ChainedConditionalReturn
+    value:           'false'
+  - key:             readability-else-after-return.WarnOnConditionVariables
+    value:           'true'
+  - key:             readability-uppercase-literal-suffix.IgnoreMacros
+    value:           'true'
+  - key:             modernize-use-nullptr.NullMacros
+    value:           'NULL'
+  - key:             modernize-make-shared.IgnoreMacros
+    value:           'true'
+  - key:             performance-unnecessary-copy-initialization.AllowedTypes
+    value:           ''
+  - key:             modernize-use-transparent-functors.SafeMode
+    value:           'false'
+  - key:             modernize-make-shared.IgnoreDefaultInitialization
+    value:           'true'
+  - key:             modernize-make-shared.IncludeStyle
+    value:           llvm
+  - key:             readability-simplify-boolean-expr.ChainedConditionalAssignment
+    value:           'false'
+  - key:             cert-oop54-cpp.WarnOnlyIfThisHasSuspiciousField
+    value:           '0'
+  - key:             readability-function-size.LineThreshold
+    value:           '4294967295'
+  - key:             performance-inefficient-vector-operation.EnableProto
+    value:           'false'
+  - key:             modernize-use-override.IgnoreDestructors
+    value:           'false'
+  - key:             modernize-loop-convert.MaxCopySize
+    value:           '16'
+  - key:             modernize-make-shared.MakeSmartPtrFunction
+    value:           'std::make_shared'
+  - key:             portability-simd-intrinsics.Suggest
+    value:           'false'
+  - key:             cppcoreguidelines-explicit-virtual-functions.IgnoreDestructors
+    value:           '1'
+  - key:             modernize-make-unique.IgnoreMacros
+    value:           'true'
+  - key:             modernize-make-shared.MakeSmartPtrFunctionHeader
+    value:           '<memory>'
+  - key:             performance-for-range-copy.AllowedTypes
+    value:           ''
+  - key:             readability-redundant-string-init.StringNames
+    value:           '::std::basic_string_view;::std::basic_string'
+  - key:             modernize-make-unique.IgnoreDefaultInitialization
+    value:           'true'
+  - key:             modernize-use-emplace.ContainersWithPushBack
+    value:           '::std::vector;::std::list;::std::deque'
+  - key:             readability-magic-numbers.IgnoreBitFieldsWidths
+    value:           'true'
+  - key:             modernize-make-unique.IncludeStyle
+    value:           llvm
+  - key:             readability-braces-around-statements.ShortStatementLines
+    value:           '0'
+  - key:             modernize-use-override.OverrideSpelling
+    value:           override
+  - key:             readability-magic-numbers.IgnoredFloatingPointValues
+    value:           '1.0;100.0;'
+  - key:             performance-inefficient-string-concatenation.StrictMode
+    value:           'false'
+  - key:             readability-implicit-bool-conversion.AllowPointerConditions
+    value:           'false'
+  - key:             readability-redundant-declaration.IgnoreMacros
+    value:           'true'
+  - key:             google-readability-braces-around-statements.ShortStatementLines
+    value:           '1'
+  - key:             modernize-make-unique.MakeSmartPtrFunction
+    value:           'std::make_unique'
+  - key:             portability-restrict-system-includes.Includes
+    value:           '*'
+  - key:             readability-else-after-return.WarnOnUnfixable
+    value:           'true'
+  - key:             modernize-use-emplace.IgnoreImplicitConstructors
+    value:           'false'
+  - key:             modernize-make-unique.MakeSmartPtrFunctionHeader
+    value:           '<memory>'
+  - key:             modernize-use-equals-delete.IgnoreMacros
+    value:           'true'
+  - key:             readability-magic-numbers.IgnoreAllFloatingPointValues
+    value:           'false'
+  - key:             readability-uppercase-literal-suffix.NewSuffixes
+    value:           ''
+  - key:             modernize-loop-convert.MinConfidence
+    value:           reasonable
+  - key:             performance-unnecessary-value-param.AllowedTypes
+    value:           ''
+  - key:             modernize-use-noexcept.UseNoexceptFalse
+    value:           'true'
+  - key:             google-readability-namespace-comments.SpacesBeforeComments
+    value:           '2'
+  - key:             readability-function-cognitive-complexity.Threshold
+    value:           '45'
+  - key:             readability-function-cognitive-complexity.IgnoreMacros
+    value:           'true'
+  - key:             cppcoreguidelines-non-private-member-variables-in-classes.IgnoreClassesWithAllMemberVariablesBeingPublic
+    value:           '1'
+  - key:             performance-faster-string-find.StringLikeClasses
+    value:           '::std::basic_string;::std::basic_string_view'
+  - key:             readability-function-size.BranchThreshold
+    value:           '4294967295'
+  - key:             readability-implicit-bool-conversion.AllowIntegerConditions
+    value:           'false'
+  - key:             readability-function-size.StatementThreshold
+    value:           '800'
+  - key:             modernize-use-default-member-init.IgnoreMacros
+    value:           'true'
+  - key:             llvm-qualified-auto.AddConstToQualified
+    value:           '0'
+  - key:             readability-identifier-naming.IgnoreMainLikeFunctions
+    value:           'false'
+  - key:             google-readability-function-size.StatementThreshold
+    value:           '800'
+  - key:             llvm-else-after-return.WarnOnConditionVariables
+    value:           '0'
+  - key:             modernize-raw-string-literal.DelimiterStem
+    value:           lit
+  - key:             modernize-use-equals-default.IgnoreMacros
+    value:           'true'
+  - key:             modernize-raw-string-literal.ReplaceShorterLiterals
+    value:           'false'
+  - key:             modernize-use-emplace.SmartPointers
+    value:           '::std::shared_ptr;::std::unique_ptr;::std::auto_ptr;::std::weak_ptr'
+  - key:             performance-inefficient-vector-operation.VectorLikeClasses
+    value:           '::std::vector'
+  - key:             modernize-use-auto.RemoveStars
+    value:           'false'
+  - key:             readability-magic-numbers.IgnorePowersOf2IntegerValues
+    value:           'false'
+  - key:             portability-simd-intrinsics.Std
+    value:           ''
+  - key:             readability-redundant-member-init.IgnoreBaseInCopyConstructors
+    value:           'false'
+  - key:             performance-unnecessary-value-param.IncludeStyle
+    value:           llvm
+  - key:             modernize-replace-disallow-copy-and-assign-macro.MacroName
+    value:           DISALLOW_COPY_AND_ASSIGN
+  - key:             llvm-else-after-return.WarnOnUnfixable
+    value:           '0'
+  - key:             readability-simplify-subscript-expr.Types
+    value:           '::std::basic_string;::std::basic_string_view;::std::vector;::std::array'
+...