<bit> and <concepts> (#1497)

Summary: The lowest common denominator build encountered for Yoga internally has been Clang 12 + MSVC 2017 stdlib. This has allowed Yoga to use C++ 20 language features, but not library features. React Native for mobile has not been bound to this restriction. Builds using that toolchain are being updated to latest MSVC 2019 stdlib (which has good C++ 20 library support), along with Clang 17 (or maybe a stop at 15) pending projects using `-fcoroutines-ts` being migrated to C++ 20. This tests out some C++ 20 standard library usages against the current Clang 12 + MSVC 2019 stdlib toolchain that didn't work before, and adds a couple concepts for better constraints/compiler error messages if misused. Yoga OSS CI tests as far back as Clang/libc++ 14 along with a similar era GCC/libstdc++ as part of tests against Ubuntu 22.04 LTS stock toolchain. Once this internal toolchain is updated, that will be the least common denominator (compared to mobile builds or any internal builds). Changelog: [Internal] Differential Revision: D51604487
facebook · Dec 7, 2023 · 699d063 · 699d063
1 parent c93734f
commit 699d063
Show file tree

Hide file tree

Showing 23 changed files with 46 additions and 130 deletions.
diff --git a/.github/actions/setup-apple/action.yml b/.github/actions/setup-apple/action.yml
@@ -7,3 +7,7 @@ runs:
     - name: Install Cocoapods
       shell: bash
       run: sudo gem install cocoapods
+
+    - uses: maxim-lobanov/setup-xcode@v1
+      with:
+        xcode-version: 14.3.1
diff --git a/.github/workflows/validate-apple.yml b/.github/workflows/validate-apple.yml
@@ -11,7 +11,7 @@ on:
 jobs:
   lint-pods:
     name: Build [CocoaPods]
-    runs-on: macos-latest
+    runs-on: macos-13
 
     steps:
       - uses: actions/checkout@v3
@@ -24,11 +24,14 @@ jobs:
 
   test:
     name: Build [SwiftPM]
-    runs-on: macos-latest
+    runs-on: macos-13
 
     steps:
       - uses: actions/checkout@v3
 
+      - name: Setup
+        uses: ./.github/actions/setup-apple
+
       - name: Build Debug
         run: swift build -c debug
 

diff --git a/enums.py b/enums.py
@@ -175,11 +175,6 @@ def to_hyphenated_lower(symbol):
             f.write(f"  return {len(values)};\n")
             f.write("} \n\n")
 
-            f.write("template <>\n")
-            f.write(f"constexpr inline int32_t bitCount<{name}>() {{\n")
-            f.write(f"  return {math.ceil(math.log(len(values), 2))};\n")
-            f.write("} \n\n")
-
         f.write(f"constexpr inline {name} scopedEnum(YG{name} unscoped) {{\n")
         f.write(f"  return static_cast<{name}>(unscoped);\n")
         f.write("}\n\n")

diff --git a/yoga/bits/BitCast.h b/yoga/bits/BitCast.h
diff --git a/yoga/enums/Align.h b/yoga/enums/Align.h
@@ -32,11 +32,6 @@ constexpr inline int32_t ordinalCount<Align>() {
   return 9;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Align>() {
-  return 4;
-} 
-
 constexpr inline Align scopedEnum(YGAlign unscoped) {
   return static_cast<Align>(unscoped);
 }

diff --git a/yoga/enums/Dimension.h b/yoga/enums/Dimension.h
@@ -25,11 +25,6 @@ constexpr inline int32_t ordinalCount<Dimension>() {
   return 2;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Dimension>() {
-  return 1;
-} 
-
 constexpr inline Dimension scopedEnum(YGDimension unscoped) {
   return static_cast<Dimension>(unscoped);
 }

diff --git a/yoga/enums/Direction.h b/yoga/enums/Direction.h
@@ -26,11 +26,6 @@ constexpr inline int32_t ordinalCount<Direction>() {
   return 3;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Direction>() {
-  return 2;
-} 
-
 constexpr inline Direction scopedEnum(YGDirection unscoped) {
   return static_cast<Direction>(unscoped);
 }

diff --git a/yoga/enums/Display.h b/yoga/enums/Display.h
@@ -25,11 +25,6 @@ constexpr inline int32_t ordinalCount<Display>() {
   return 2;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Display>() {
-  return 1;
-} 
-
 constexpr inline Display scopedEnum(YGDisplay unscoped) {
   return static_cast<Display>(unscoped);
 }

diff --git a/yoga/enums/Edge.h b/yoga/enums/Edge.h
@@ -32,11 +32,6 @@ constexpr inline int32_t ordinalCount<Edge>() {
   return 9;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Edge>() {
-  return 4;
-} 
-
 constexpr inline Edge scopedEnum(YGEdge unscoped) {
   return static_cast<Edge>(unscoped);
 }

diff --git a/yoga/enums/ExperimentalFeature.h b/yoga/enums/ExperimentalFeature.h
@@ -25,11 +25,6 @@ constexpr inline int32_t ordinalCount<ExperimentalFeature>() {
   return 2;
 } 
 
-template <>
-constexpr inline int32_t bitCount<ExperimentalFeature>() {
-  return 1;
-} 
-
 constexpr inline ExperimentalFeature scopedEnum(YGExperimentalFeature unscoped) {
   return static_cast<ExperimentalFeature>(unscoped);
 }

diff --git a/yoga/enums/FlexDirection.h b/yoga/enums/FlexDirection.h
@@ -27,11 +27,6 @@ constexpr inline int32_t ordinalCount<FlexDirection>() {
   return 4;
 } 
 
-template <>
-constexpr inline int32_t bitCount<FlexDirection>() {
-  return 2;
-} 
-
 constexpr inline FlexDirection scopedEnum(YGFlexDirection unscoped) {
   return static_cast<FlexDirection>(unscoped);
 }

diff --git a/yoga/enums/Gutter.h b/yoga/enums/Gutter.h
@@ -26,11 +26,6 @@ constexpr inline int32_t ordinalCount<Gutter>() {
   return 3;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Gutter>() {
-  return 2;
-} 
-
 constexpr inline Gutter scopedEnum(YGGutter unscoped) {
   return static_cast<Gutter>(unscoped);
 }

diff --git a/yoga/enums/Justify.h b/yoga/enums/Justify.h
@@ -29,11 +29,6 @@ constexpr inline int32_t ordinalCount<Justify>() {
   return 6;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Justify>() {
-  return 3;
-} 
-
 constexpr inline Justify scopedEnum(YGJustify unscoped) {
   return static_cast<Justify>(unscoped);
 }

diff --git a/yoga/enums/LogLevel.h b/yoga/enums/LogLevel.h
@@ -29,11 +29,6 @@ constexpr inline int32_t ordinalCount<LogLevel>() {
   return 6;
 } 
 
-template <>
-constexpr inline int32_t bitCount<LogLevel>() {
-  return 3;
-} 
-
 constexpr inline LogLevel scopedEnum(YGLogLevel unscoped) {
   return static_cast<LogLevel>(unscoped);
 }

diff --git a/yoga/enums/MeasureMode.h b/yoga/enums/MeasureMode.h
@@ -26,11 +26,6 @@ constexpr inline int32_t ordinalCount<MeasureMode>() {
   return 3;
 } 
 
-template <>
-constexpr inline int32_t bitCount<MeasureMode>() {
-  return 2;
-} 
-
 constexpr inline MeasureMode scopedEnum(YGMeasureMode unscoped) {
   return static_cast<MeasureMode>(unscoped);
 }

diff --git a/yoga/enums/NodeType.h b/yoga/enums/NodeType.h
@@ -25,11 +25,6 @@ constexpr inline int32_t ordinalCount<NodeType>() {
   return 2;
 } 
 
-template <>
-constexpr inline int32_t bitCount<NodeType>() {
-  return 1;
-} 
-
 constexpr inline NodeType scopedEnum(YGNodeType unscoped) {
   return static_cast<NodeType>(unscoped);
 }

diff --git a/yoga/enums/Overflow.h b/yoga/enums/Overflow.h
@@ -26,11 +26,6 @@ constexpr inline int32_t ordinalCount<Overflow>() {
   return 3;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Overflow>() {
-  return 2;
-} 
-
 constexpr inline Overflow scopedEnum(YGOverflow unscoped) {
   return static_cast<Overflow>(unscoped);
 }

diff --git a/yoga/enums/PositionType.h b/yoga/enums/PositionType.h
@@ -26,11 +26,6 @@ constexpr inline int32_t ordinalCount<PositionType>() {
   return 3;
 } 
 
-template <>
-constexpr inline int32_t bitCount<PositionType>() {
-  return 2;
-} 
-
 constexpr inline PositionType scopedEnum(YGPositionType unscoped) {
   return static_cast<PositionType>(unscoped);
 }

diff --git a/yoga/enums/Unit.h b/yoga/enums/Unit.h
@@ -27,11 +27,6 @@ constexpr inline int32_t ordinalCount<Unit>() {
   return 4;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Unit>() {
-  return 2;
-} 
-
 constexpr inline Unit scopedEnum(YGUnit unscoped) {
   return static_cast<Unit>(unscoped);
 }

diff --git a/yoga/enums/Wrap.h b/yoga/enums/Wrap.h
@@ -26,11 +26,6 @@ constexpr inline int32_t ordinalCount<Wrap>() {
   return 3;
 } 
 
-template <>
-constexpr inline int32_t bitCount<Wrap>() {
-  return 2;
-} 
-
 constexpr inline Wrap scopedEnum(YGWrap unscoped) {
   return static_cast<Wrap>(unscoped);
 }

diff --git a/yoga/enums/YogaEnums.h b/yoga/enums/YogaEnums.h
@@ -7,33 +7,52 @@
 
 #pragma once
 
+#include <bit>
 #include <iterator>
 #include <type_traits>
 
 namespace facebook::yoga {
 
+/**
+ * Concept for any enum/enum class
+ */
 template <typename EnumT>
+concept Enumeration = std::is_enum_v<EnumT>;
+
+/**
+ * Count of ordinals in a Yoga enum which is sequential
+ */
+template <Enumeration EnumT>
 constexpr inline int32_t ordinalCount();
 
 /**
- * Count of bits needed to represent every ordinal
+ * Concept for a yoga enum which is sequential
  */
 template <typename EnumT>
-constexpr inline int32_t bitCount();
+concept HasOrdinality = (ordinalCount<EnumT>() > 0);
+
+/**
+ * Count of bits needed to represent every ordinal
+ */
+template <HasOrdinality EnumT>
+constexpr inline int32_t bitCount() {
+  return std::bit_width(
+      static_cast<std::underlying_type_t<EnumT>>(ordinalCount<EnumT>() - 1));
+}
 
 /**
  * Polyfill of C++ 23 to_underlying()
  * https://en.cppreference.com/w/cpp/utility/to_underlying
  */
-constexpr auto to_underlying(auto e) noexcept {
+constexpr auto to_underlying(Enumeration auto e) noexcept {
   return static_cast<std::underlying_type_t<decltype(e)>>(e);
 }
 
 /**
  * Convenience function to iterate through every value in a Yoga enum as part of
  * a range-based for loop.
  */
-template <typename EnumT>
+template <HasOrdinality EnumT>
 auto ordinals() {
   struct Iterator {
     EnumT e{};

diff --git a/yoga/numeric/Comparison.h b/yoga/numeric/Comparison.h
@@ -10,27 +10,32 @@
 #include <algorithm>
 #include <array>
 #include <cmath>
+#include <concepts>
 
 #include <yoga/Yoga.h>
 
 namespace facebook::yoga {
 
-constexpr bool isUndefined(auto value) {
+constexpr bool isUndefined(std::floating_point auto value) {
   return value != value;
 }
 
-constexpr bool isDefined(auto value) {
+constexpr bool isDefined(std::floating_point auto value) {
   return !isUndefined(value);
 }
 
-constexpr auto maxOrDefined(auto a, auto b) {
+constexpr auto maxOrDefined(
+    std::floating_point auto a,
+    std::floating_point auto b) {
   if (yoga::isDefined(a) && yoga::isDefined(b)) {
     return std::max(a, b);
   }
   return yoga::isUndefined(a) ? b : a;
 }
 
-constexpr auto minOrDefined(auto a, auto b) {
+constexpr auto minOrDefined(
+    std::floating_point auto a,
+    std::floating_point auto b) {
   if (yoga::isDefined(a) && yoga::isDefined(b)) {
     return std::min(a, b);
   }