Merge pull request swiftlang#77695 from atrick/handle_markdep

[NFC] mark_dependence handling for coroutines and accessors.

Author: atrick

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift

@@ -45,13 +45,23 @@ let lifetimeDependenceDiagnosticsPass = FunctionPass(
     // Indirect results are not checked here. Type checking ensures
     // that they have a lifetime dependence.
     if let lifetimeDep = LifetimeDependence(argument, context) {
-      analyze(dependence: lifetimeDep, context)
+      _ = analyze(dependence: lifetimeDep, context)
     }
   }
   for instruction in function.instructions {
     if let markDep = instruction as? MarkDependenceInst, markDep.isUnresolved {
       if let lifetimeDep = LifetimeDependence(markDep, context) {
-        analyze(dependence: lifetimeDep, context)
+        if analyze(dependence: lifetimeDep, context) {
+          // Note: This promotes the mark_dependence flag but does not invalidate SIL; preserving analyses is good,
+          // but the change won't appear in -sil-print-function. Ideally, we could notify context of a flag change
+          // without invalidating analyses.
+          lifetimeDep.resolve(context)
+        }
+      } else {
+        // For now, if the mark_dependence wasn't recognized as a lifetime dependence, conservatively settle it as
+        // escaping. In the future, we should not need this because, for escapable types, mark_dependence [unresolved]
+        // will all be settled during an early LifetimeNormalization pass.
+        markDep.settleToEscaping()
       }
       continue
     }
@@ -61,7 +71,7 @@ let lifetimeDependenceDiagnosticsPass = FunctionPass(
       apply.resultOrYields.forEach {
         if let lifetimeDep = LifetimeDependence(unsafeApplyResult: $0,
                                                 context) {
-          analyze(dependence: lifetimeDep, context)
+          _ = analyze(dependence: lifetimeDep, context)
         }
       }
       continue
@@ -74,8 +84,9 @@ let lifetimeDependenceDiagnosticsPass = FunctionPass(
 /// 1. Compute the LifetimeDependence scope.
 ///
 /// 2. Walk down all dependent values checking that they are within range.
-private func analyze(dependence: LifetimeDependence,
-  _ context: FunctionPassContext) {
+///
+/// Return true on success.
+private func analyze(dependence: LifetimeDependence, _ context: FunctionPassContext) -> Bool {
   log("Dependence scope:\n\(dependence)")
 
   // Compute this dependence scope.
@@ -91,10 +102,7 @@ private func analyze(dependence: LifetimeDependence,
   var walker = DiagnoseDependenceWalker(diagnostics, context)
   defer { walker.deinitialize() }
   _ = walker.walkDown(root: dependence.dependentValue)
-
-  if !error {
-    dependence.resolve(context)
-  }
+  return !error
 }
 
 /// Analyze and diagnose a single LifetimeDependence.

SwiftCompilerSources/Sources/SIL/Instruction.swift

@@ -976,6 +976,10 @@ class MarkDependenceInst : SingleValueInstruction {
   public func resolveToNonEscaping() {
     bridged.MarkDependenceInst_resolveToNonEscaping()
   }
+
+  public func settleToEscaping() {
+    bridged.MarkDependenceInst_settleToEscaping()
+  }
 }
 
 final public class RefToBridgeObjectInst : SingleValueInstruction {
@@ -1344,7 +1348,7 @@ final public class AbortApplyInst : Instruction, UnaryInstruction {
 
 extension BeginApplyInst : ScopedInstruction {
   public var endOperands: LazyFilterSequence<UseList> {
-    return token.uses.lazy.filter { $0.endsLifetime }
+    return token.uses.lazy.filter { $0.isScopeEndingUse }
   }
 }
 

SwiftCompilerSources/Sources/SIL/Operand.swift

@@ -192,6 +192,19 @@ extension Operand {
   }
 }
 
+extension Operand {
+  /// A scope ending use is a consuming use for normal borrow scopes, but it also applies to intructions that end the
+  /// scope of an address (end_access) or a token (end_apply, abort_apply),
+  public var isScopeEndingUse: Bool {
+    switch instruction {
+    case is EndBorrowInst, is EndAccessInst, is EndApplyInst, is AbortApplyInst:
+      return true
+    default:
+      return false
+    }
+  }
+}
+
 extension OptionalBridgedOperand {
   init(bridged: BridgedOperand?) {
     self = OptionalBridgedOperand(op: bridged?.op)

docs/SIL.rst

@@ -5699,6 +5699,8 @@ mark_dependence
 
   %2 = mark_dependence %value : $*T on %base : $Builtin.NativeObject
 
+``%base`` must not be identical to ``%value``.
+
 Indicates that the validity of ``%value`` depends on the value of
 ``%base``. Operations that would destroy ``%base`` must not be moved
 before any instructions which depend on the result of this
@@ -5715,7 +5717,7 @@ the dependency is on the current value stored in the address.
 The optional ``nonescaping`` attribute indicates that no value derived
 from ``%value`` escapes the lifetime of ``%base``. As with escaping
 ``mark_dependence``, all values transitively forwarded from ``%value``
-must be destroyed within the lifetime of ` `%base``. Unlike escaping
+must be destroyed within the lifetime of ``%base``. Unlike escaping
 ``mark_dependence``, this must be statically verifiable. Additionally,
 unlike escaping ``mark_dependence``, derived values include copies of
 ``%value`` and values transitively forwarded from those copies. If

include/swift/SIL/SILBridging.h

@@ -788,6 +788,7 @@ struct BridgedInstruction {
   BRIDGED_INLINE SwiftInt AssignInst_getAssignOwnership() const;
   BRIDGED_INLINE MarkDependenceKind MarkDependenceInst_dependenceKind() const;
   BRIDGED_INLINE void MarkDependenceInst_resolveToNonEscaping() const;
+  BRIDGED_INLINE void MarkDependenceInst_settleToEscaping() const;
   BRIDGED_INLINE SwiftInt BeginAccessInst_getAccessKind() const;
   BRIDGED_INLINE bool BeginAccessInst_isStatic() const;
   BRIDGED_INLINE bool BeginAccessInst_isUnsafe() const;

include/swift/SIL/SILBridgingImpl.h

@@ -1387,6 +1387,10 @@ void BridgedInstruction::MarkDependenceInst_resolveToNonEscaping() const {
   getAs<swift::MarkDependenceInst>()->resolveToNonEscaping();
 }
 
+void BridgedInstruction::MarkDependenceInst_settleToEscaping() const {
+  getAs<swift::MarkDependenceInst>()->settleToEscaping();
+}
+
 SwiftInt BridgedInstruction::BeginAccessInst_getAccessKind() const {
   return (SwiftInt)getAs<swift::BeginAccessInst>()->getAccessKind();
 }

lib/AST/LifetimeDependence.cpp

@@ -441,8 +441,7 @@ std::optional<LifetimeDependenceInfo> LifetimeDependenceInfo::fromDependsOn(
     auto kind = descriptor.getParsedLifetimeDependenceKind();
 
     if (kind == ParsedLifetimeDependenceKind::Scope &&
-        (!isGuaranteedParameterInCallee(paramConvention) &&
-         !isMutatingParameter(paramConvention))) {
+        isConsumedParameterInCallee(paramConvention)) {
       diags.diagnose(loc, diag::lifetime_dependence_cannot_use_kind, "_scope",
                      getStringForParameterConvention(paramConvention));
       return true;