Annotate some Span and InlineArray's methods with semantics

Author: meg-gupta

include/swift/AST/SemanticAttrs.def

@@ -160,5 +160,8 @@ SEMANTICS_ATTR(DELETE_IF_UNUSED, "sil.optimizer.delete_if_unused")
 // Force the use of the frame pointer for the specified function
 SEMANTICS_ATTR(USE_FRAME_POINTER, "use_frame_pointer")
 
+SEMANTICS_ATTR(FIXED_STORAGE_CHECK_INDEX, "fixed_storage.check_index")
+SEMANTICS_ATTR(FIXED_STORAGE_GET_COUNT, "fixed_storage.get_count")
+
 #undef SEMANTICS_ATTR
 

lib/SILOptimizer/Transforms/PerformanceInliner.cpp

@@ -860,7 +860,8 @@ static std::optional<bool> shouldInlineGeneric(FullApplySite AI,
   // because they need to be preserved, so that the optimizer
   // can properly optimize a user code later.
   ModuleDecl *SwiftModule = Callee->getModule().getSwiftModule();
-  if (Callee->hasSemanticsAttrThatStartsWith("array.") &&
+  if ((Callee->hasSemanticsAttrThatStartsWith("array.") ||
+       Callee->hasSemanticsAttrThatStartsWith("fixed_storage.")) &&
       (SwiftModule->isStdlibModule() || SwiftModule->isOnoneSupportModule()))
     return false;
 
@@ -1167,8 +1168,9 @@ void SILPerformanceInliner::collectAppliesToInline(
         Weight W(BlockWeight, WeightCorrections.lookup(AI));
 
         if (decideInWarmBlock(AI, W, constTracker, NumCallerBlocks,
-                              BBToWeightMap))
+                              BBToWeightMap)) {
           InitialCandidates.push_back(AI);
+        }
       }
     }
 

lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp

@@ -594,6 +594,11 @@ SemanticFunctionLevel swift::getSemanticFunctionLevel(SILFunction *function) {
   //
   // Compiler "hints" and informational annotations (like remarks) should
   // ideally use a separate annotation rather than @_semantics.
+
+  if (isFixedStorageSemanticsCallKind(function)) {
+    return SemanticFunctionLevel::Fundamental;
+  }
+
   switch (getArraySemanticsKind(function)) {
   case ArrayCallKind::kNone:
     return SemanticFunctionLevel::Transient;

stdlib/public/core/InlineArray.swift

@@ -236,6 +236,8 @@ extension InlineArray where Element: ~Copyable {
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
   @_transparent
+  @_semantics("fixed_storage.get_count")
+  @inline(__always)
   public var count: Int {
     count
   }
@@ -320,6 +322,13 @@ extension InlineArray where Element: ~Copyable {
     i &- 1
   }
 
+  @_alwaysEmitIntoClient
+  @_semantics("fixed_storage.check_index")
+  @inline(__always)
+  internal func _checkIndex(_ i: Int) {
+    _precondition(indices.contains(i), "Index out of bounds")
+  }
+
   /// Accesses the element at the specified position.
   ///
   /// The following example accesses an element of an array through its
@@ -345,15 +354,13 @@ extension InlineArray where Element: ~Copyable {
   public subscript(_ i: Int) -> Element {
     @_transparent
     unsafeAddress {
-      _precondition(indices.contains(i), "Index out of bounds")
-
+      _checkIndex(i)
       return unsafe _address + i
     }
 
     @_transparent
     unsafeMutableAddress {
-      _precondition(indices.contains(i), "Index out of bounds")
-
+       _checkIndex(i)
       return unsafe _mutableAddress + i
     }
   }

stdlib/public/core/Span/Span.swift

@@ -367,6 +367,7 @@ extension Span where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
+  @_semantics("fixed_storage.get_count")
   public var count: Int { _count }
 
   /// A Boolean value indicating whether the span is empty.
@@ -390,6 +391,12 @@ extension Span where Element: ~Copyable {
 
 @available(SwiftStdlib 6.1, *)
 extension Span where Element: ~Copyable {
+  @_semantics("fixed_storage.check_index")
+  @inline(__always)
+  @_alwaysEmitIntoClient
+  internal func _checkIndex(_ position: Index) {
+    _precondition(indices.contains(position), "Index out of bounds")
+  }
 
   /// Accesses the element at the specified position in the `Span`.
   ///
@@ -401,7 +408,7 @@ extension Span where Element: ~Copyable {
   public subscript(_ position: Index) -> Element {
     //FIXME: change to unsafeRawAddress when ready
     unsafeAddress {
-      _precondition(indices.contains(position), "Index out of bounds")
+      _checkIndex(position)
       return unsafe _unsafeAddressOfElement(unchecked: position)
     }
   }
@@ -437,6 +444,15 @@ extension Span where Element: ~Copyable {
 
 @available(SwiftStdlib 6.1, *)
 extension Span where Element: BitwiseCopyable {
+  @_semantics("fixed_storage.check_index")
+  @inline(__always)
+  @_alwaysEmitIntoClient
+  internal func _checkIndex(_ position: Index) {
+    _precondition(
+      UInt(bitPattern: position) <  UInt(bitPattern: _count),
+      "Index out of bounds"
+    )
+  }
 
   /// Accesses the element at the specified position in the `Span`.
   ///
@@ -447,10 +463,7 @@ extension Span where Element: BitwiseCopyable {
   @_alwaysEmitIntoClient
   public subscript(_ position: Index) -> Element {
     get {
-      _precondition(
-        UInt(bitPattern: position) <  UInt(bitPattern: _count),
-        "Index out of bounds"
-      )
+      _checkIndex(position)
       return unsafe self[unchecked: position]
     }
   }