Remove the optimize.sil.preserve_exclusivity attribute.

Author: atrick

include/swift/Strings.h

@@ -13,9 +13,6 @@
 #ifndef SWIFT_STRINGS_H
 #define SWIFT_STRINGS_H
 
-#include "swift/Basic/LLVM.h"
-#include "llvm/ADT/StringRef.h"
-
 namespace swift {
 
 /// The extension for serialized modules.
@@ -92,10 +89,6 @@ constexpr static const char BUILTIN_TYPE_NAME_VEC[] = "Builtin.Vec";
 constexpr static const char BUILTIN_TYPE_NAME_SILTOKEN[] = "Builtin.SILToken";
 /// The name of the Builtin type for Word
 constexpr static const char BUILTIN_TYPE_NAME_WORD[] = "Builtin.Word";
-
-constexpr static StringLiteral OPTIMIZE_SIL_PRESERVE_EXCLUSIVITY =
-    "optimize.sil.preserve_exclusivity";
-
 } // end namespace swift
 
 #endif // SWIFT_STRINGS_H

lib/SILOptimizer/Mandatory/AccessMarkerElimination.cpp

@@ -31,7 +31,6 @@
 #include "swift/Basic/Range.h"
 #include "swift/SIL/SILFunction.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/Strings.h"
 #include "llvm/Support/CommandLine.h"
 
 using namespace swift;
@@ -190,12 +189,6 @@ struct AccessMarkerEliminationPass : SILModuleTransform {
   void run() override {
     auto &M = *getModule();
     for (auto &F : M) {
-      if (F.hasSemanticsAttr(OPTIMIZE_SIL_PRESERVE_EXCLUSIVITY)) {
-        DEBUG(llvm::dbgs() << "Skipping " << F.getName() << ". Found "
-                           << OPTIMIZE_SIL_PRESERVE_EXCLUSIVITY << " tag!\n");
-        continue;
-      }
-
       bool removedAny = AccessMarkerElimination(&F).stripMarkers();
 
       // Only invalidate analyses if we removed some markers.

stdlib/public/core/KeyPath.swift

@@ -625,41 +625,6 @@ internal enum KeyPathComponent: Hashable {
   }
 }
 
-// _semantics("optimize.sil.preserve_exclusivity" forces the compiler to
-// generate access markers regardless of the current build settings. This way,
-// user code that accesses keypaths are properly enforced even if the standard
-// library has exclusivity checking internally disabled. The semantic attribute
-// must be consistently applied to both the begin and end unpaired access
-// markers, otherwise the runtime will fail catastrophically and unpredictably.
-// This relies on Swift module serialization occurring before these _semantic
-// function are inlined, since inlining would unpredictably cause the attribute
-// to be dropped.
-//
-// An exclusivity violation will report the caller's stack frame location.
-// Runtime diagnostics will be improved by inlining this function. However, this
-// cannot be marked @transparent because it can't be inlined prior to
-// serialization.
-@inlinable
-@inline(__always)
-@_semantics("optimize.sil.preserve_exclusivity")
-func beginAccessHelper<T>(_ address: Builtin.RawPointer, _ accessRecordPtr: Builtin.RawPointer, _ type: T.Type) {
-  Builtin.beginUnpairedModifyAccess(address, accessRecordPtr, type)
-}
-
-@inlinable
-@inline(__always)
-@_semantics("optimize.sil.preserve_exclusivity")
-func endAccessHelper(_ accessRecordPtr: Builtin.RawPointer) {
-  Builtin.endUnpairedAccess(accessRecordPtr)
-}
-
-@inlinable
-@inline(__always)
-@_semantics("optimize.sil.preserve_exclusivity")
-func instantaneousAccessHelper<T>(_ address: Builtin.RawPointer, _ type: T.Type) {
-  Builtin.performInstantaneousReadAccess(address, T.self)
-}
-
 // A class that maintains ownership of another object while a mutable projection
 // into it is underway. The lifetime of the instance of this class is also used
 // to begin and end exclusive 'modify' access to the projected address.
@@ -714,7 +679,7 @@ internal final class ClassHolder<ProjectionType> {
 
     // Begin a 'modify' access to the address. This access is ended in
     // ClassHolder's deinitializer.
-    beginAccessHelper(address._rawValue, accessRecordPtr, type)
+    Builtin.beginUnpairedModifyAccess(address._rawValue, accessRecordPtr, type)
 
     return holder
   }
@@ -724,7 +689,7 @@ internal final class ClassHolder<ProjectionType> {
     let accessRecordPtr = Builtin.projectTailElems(self, AccessRecord.self)
 
     // Ends the access begun in _create().
-    endAccessHelper(accessRecordPtr)
+    Builtin.endUnpairedAccess(accessRecordPtr)
   }
 }
 
@@ -1275,7 +1240,8 @@ internal struct RawKeyPathComponent {
       // Perform an instaneous record access on the address in order to
       // ensure that the read will not conflict with an already in-progress
       // 'modify' access.
-      instantaneousAccessHelper(offsetAddress._rawValue, NewValue.self)
+      Builtin.performInstantaneousReadAccess(offsetAddress._rawValue,
+        NewValue.self)
       return .continue(offsetAddress
         .assumingMemoryBound(to: NewValue.self)
         .pointee)