Merge pull request #85843 from eeckstein/fix-verifier

Don't verify that there are no stores in read-only access scopes if there is a conflicting scope

Author: eeckstein

SwiftCompilerSources/Sources/SIL/Utilities/Verifier.swift

@@ -258,6 +258,15 @@ private struct MutatingUsesWalker : AddressDefUseWalker {
     }
   }
 
+  mutating func walkDown(address: Operand, path: UnusedWalkingPath) -> WalkResult {
+    if let beginAccess = address.instruction as? BeginAccessInst, beginAccess.accessKind != .read {
+      // Don't verify that there are no stores in read-only access scopes if there is a conflicting scope.
+      // This is a programming error, but the compiler should not crash. The violation is caught at runtime.
+      return .continueWalk
+    }
+    return walkDownDefault(address: address, path: path)
+  }
+
   mutating func leafUse(address: Operand, path: UnusedWalkingPath) -> WalkResult {
     if address.isMutatedAddress {
       mutatingInstructions.insert(address.instruction)
@@ -288,7 +297,7 @@ private extension Operand {
       {
         switch convention {
         case .indirectIn, .indirectInGuaranteed:
-          // Such operands are consumed by the `partial_apply` and therefore cound as "written".
+          // Such operands are consumed by the `partial_apply` and therefore count as "written".
           return true
         default:
           return false

test/SIL/verifier-no-fail-access-scope3.sil

@@ -0,0 +1,26 @@
+
+// RUN: %target-sil-opt %s -o /dev/null
+
+// REQUIRES: asserts
+
+sil_stage canonical
+
+// Don't verify that there are no stores in read-only access scopes if there is a conflicting scope.
+// This is a programming error, but the compiler should not crash. The violation is caught at runtime.
+
+import Builtin
+import Swift
+
+sil_global @g : $Int
+
+sil [ossa] @write_in_read_only_scope : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = global_addr @g : $*Int
+  %2 = begin_access [read] [dynamic] %1
+  %3 = begin_access [modify] [dynamic] %1
+  store %0 to [trivial] %3
+  end_access %3
+  end_access %2
+  %7 = tuple()
+  return %7
+}