Merge pull request swiftlang#81649 from eeckstein/global-inlinearray-initialization

Allow more complex InlineArray initializations to end up in a statically initialized global

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift

@@ -376,3 +376,75 @@ private extension Instruction {
     return shiftValue > 0
   }
 }
+
+/// Analyses the global initializer function and returns the `alloc_global` and `store`
+/// instructions which initialize the global.
+/// Returns nil if `function` has any side-effects beside initializing the global.
+///
+/// The function's single basic block must contain following code pattern:
+/// ```
+///   alloc_global @the_global
+///   %a = global_addr @the_global
+///   %i = some_const_initializer_insts
+///   store %i to %a
+/// ```
+///
+/// For all other instructions `handleUnknownInstruction` is called and such an instruction
+/// is accepted if `handleUnknownInstruction` returns true.
+private func getGlobalInitialization(
+  of function: Function,
+  _ context: some Context,
+  handleUnknownInstruction: (Instruction) -> Bool
+) -> (allocInst: AllocGlobalInst, storeToGlobal: StoreInst)? {
+  guard let block = function.blocks.singleElement else {
+    return nil
+  }
+
+  var allocInst: AllocGlobalInst? = nil
+  var globalAddr: GlobalAddrInst? = nil
+  var store: StoreInst? = nil
+
+  for inst in block.instructions {
+    switch inst {
+    case is ReturnInst,
+         is DebugValueInst,
+         is DebugStepInst,
+         is BeginAccessInst,
+         is EndAccessInst:
+      continue
+    case let agi as AllocGlobalInst:
+      if allocInst == nil {
+        allocInst = agi
+        continue
+      }
+    case let ga as GlobalAddrInst:
+      if let agi = allocInst, agi.global == ga.global {
+        globalAddr = ga
+      }
+      continue
+    case let si as StoreInst:
+      if store == nil,
+         let ga = globalAddr,
+         si.destination == ga
+      {
+        store = si
+        continue
+      }
+    // Note that the initializer must not contain a `global_value` because `global_value` needs to
+    // initialize the class metadata at runtime.
+    default:
+      if inst.isValidInStaticInitializerOfGlobal(context) {
+        continue
+      }
+    }
+    if handleUnknownInstruction(inst) {
+      continue
+    }
+    return nil
+  }
+  if let store = store {
+    return (allocInst: allocInst!, storeToGlobal: store)
+  }
+  return nil
+}
+

SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift

@@ -293,13 +293,6 @@ private extension Value {
       return self
     }
   }
-
-  var lookThroughTruncOrBitCast: Value {
-    if let truncOrBitCast = self as? BuiltinInst, truncOrBitCast.id == .TruncOrBitCast {
-      return truncOrBitCast.arguments[0]
-    }
-    return self
-  }
 }
 
 private extension BuiltinInst {

SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyPointerToAddress.swift

@@ -159,7 +159,7 @@ extension AddressUseVisitor {
            .GenericFDiv, .GenericMul, .GenericFMul, .GenericSDiv,
            .GenericExactSDiv, .GenericShl, .GenericSRem, .GenericSub,
            .GenericFSub, .GenericUDiv, .GenericExactUDiv, .GenericURem,
-           .GenericFRem, .GenericXor, .TaskRunInline, .ZeroInitializer,
+           .GenericFRem, .GenericXor, .TaskRunInline, .ZeroInitializer, .PrepareInitialization,
            .GetEnumTag, .InjectEnumTag:
         return leafAddressUse(of: operand)
       default:

SwiftCompilerSources/Sources/Optimizer/Utilities/AddressUtils.swift

@@ -45,6 +45,13 @@ extension Value {
     }
   }
 
+  var lookThroughTruncOrBitCast: Value {
+    if let truncOrBitCast = self as? BuiltinInst, truncOrBitCast.id == .TruncOrBitCast {
+      return truncOrBitCast.arguments[0]
+    }
+    return self
+  }
+
   func isInLexicalLiverange(_ context: some Context) -> Bool {
     var worklist = ValueWorklist(context)
     defer { worklist.deinitialize() }
@@ -846,77 +853,6 @@ extension InstructionRange {
   }
 }
 
-/// Analyses the global initializer function and returns the `alloc_global` and `store`
-/// instructions which initialize the global.
-/// Returns nil if `function` has any side-effects beside initializing the global.
-///
-/// The function's single basic block must contain following code pattern:
-/// ```
-///   alloc_global @the_global
-///   %a = global_addr @the_global
-///   %i = some_const_initializer_insts
-///   store %i to %a
-/// ```
-/// 
-/// For all other instructions `handleUnknownInstruction` is called and such an instruction
-/// is accepted if `handleUnknownInstruction` returns true.
-func getGlobalInitialization(
-  of function: Function,
-  _ context: some Context,
-  handleUnknownInstruction: (Instruction) -> Bool
-) -> (allocInst: AllocGlobalInst, storeToGlobal: StoreInst)? {
-  guard let block = function.blocks.singleElement else {
-    return nil
-  }
-
-  var allocInst: AllocGlobalInst? = nil
-  var globalAddr: GlobalAddrInst? = nil
-  var store: StoreInst? = nil
-
-  for inst in block.instructions {
-    switch inst {
-    case is ReturnInst,
-         is DebugValueInst,
-         is DebugStepInst,
-         is BeginAccessInst,
-         is EndAccessInst:
-      continue
-    case let agi as AllocGlobalInst:
-      if allocInst == nil {
-        allocInst = agi
-        continue
-      }
-    case let ga as GlobalAddrInst:
-      if let agi = allocInst, agi.global == ga.global {
-        globalAddr = ga
-      }
-      continue
-    case let si as StoreInst:
-      if store == nil,
-         let ga = globalAddr,
-         si.destination == ga
-      {
-        store = si
-        continue
-      }
-    // Note that the initializer must not contain a `global_value` because `global_value` needs to
-    // initialize the class metadata at runtime.
-    default:
-      if inst.isValidInStaticInitializerOfGlobal(context) {
-        continue
-      }
-    }
-    if handleUnknownInstruction(inst) {
-      continue
-    }
-    return nil
-  }
-  if let store = store {
-    return (allocInst: allocInst!, storeToGlobal: store)
-  }
-  return nil
-}
-
 func canDynamicallyCast(from sourceType: CanonicalType, to destType: CanonicalType,
                         in function: Function, sourceTypeIsExact: Bool
 ) -> Bool? {

SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift

@@ -29,6 +29,8 @@ final public class GlobalVariable : CustomStringConvertible, HasShortDescription
 
   public var shortDescription: String { name.string }
 
+  public var type: Type { Type(bridged: bridged.getType()) }
+
   public var isLet: Bool { bridged.isLet() }
 
   public var linkage: Linkage { bridged.getLinkage().linkage }

SwiftCompilerSources/Sources/SIL/GlobalVariable.swift

@@ -851,6 +851,10 @@ BUILTIN_MISC_OPERATION_WITH_SILGEN(Alignof, "alignof", "n", Special)
 /// own rules.
 BUILTIN_MISC_OPERATION_WITH_SILGEN(ZeroInitializer, "zeroInitializer", "n", Special)
 
+/// Like `zeroInitializer`, but does not actually initialize the memory.
+/// It only indicates to mandatory passes that the memory is going to be initialized.
+BUILTIN_MISC_OPERATION(PrepareInitialization, "prepareInitialization", "n", Special)
+
 // getCurrentExecutor: () async -> Builtin.Executor?
 //
 // Retrieve the SerialExecutorRef on which the current asynchronous

include/swift/AST/Builtins.def

@@ -288,6 +288,7 @@ TransitiveAddressWalker<Impl>::walk(SILValue projectedAddress) {
         case BuiltinValueKind::GenericXor:
         case BuiltinValueKind::TaskRunInline:
         case BuiltinValueKind::ZeroInitializer:
+        case BuiltinValueKind::PrepareInitialization:
         case BuiltinValueKind::GetEnumTag:
         case BuiltinValueKind::InjectEnumTag:
         case BuiltinValueKind::AddressOfRawLayout:

include/swift/SIL/AddressWalker.h

@@ -587,6 +587,7 @@ struct BridgedGlobalVar {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef getName() const;
   BRIDGED_INLINE bool isLet() const;
   BRIDGED_INLINE void setLet(bool value) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getType() const;
   BRIDGED_INLINE BridgedLinkage getLinkage() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSourceLoc getSourceLocation() const;
   BRIDGED_INLINE bool isPossiblyUsedExternally() const;

include/swift/SIL/SILBridging.h

@@ -918,6 +918,10 @@ bool BridgedGlobalVar::isLet() const { return getGlobal()->isLet(); }
 
 void BridgedGlobalVar::setLet(bool value) const { getGlobal()->setLet(value); }
 
+BridgedType BridgedGlobalVar::getType() const {
+  return getGlobal()->getLoweredType();
+}
+
 BridgedLinkage BridgedGlobalVar::getLinkage() const {
   return (BridgedLinkage)getGlobal()->getLinkage();
 }