Merge pull request swiftlang#77780 from DougGregor/willthrow-no-locks

Treat swift_willThrow(Typed) as not locking or performing allocation

Author: DougGregor

lib/SIL/Utils/InstructionUtils.cpp

@@ -465,6 +465,27 @@ static RuntimeEffect metadataEffect(SILType ty) {
   return RuntimeEffect::MetaData;
 }
 
+/// Whether this particular SIL function is known a prior not to use the
+/// generic metadata it is given.
+static bool knownToNotUseGenericMetadata(SILFunction &f) {
+  // swift_willThrowTypedImpl only uses the generic metadata when a global
+  // hook has been installed, so we treat it as if the generic metadata is
+  // unused.
+  if (f.getName() == "swift_willThrowTypedImpl")
+    return true;
+
+  return false;
+}
+
+/// Whether this apply site is a call to a functio that is known not to use
+/// the generic metadata it is given.
+static bool knownToNotUseGenericMetadata(ApplySite &as) {
+  if (auto *callee = as.getCalleeFunction()) {
+    return knownToNotUseGenericMetadata(*callee);
+  }
+  return false;
+}
+
 RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType) {
   auto ifNonTrivial = [&](SILType type, RuntimeEffect effect) -> RuntimeEffect {
     // Nonescaping closures are modeled with ownership to track borrows, but
@@ -1017,7 +1038,7 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
       }
     }
 
-    if (!as.getSubstitutionMap().empty())
+    if (!as.getSubstitutionMap().empty() && !knownToNotUseGenericMetadata(as))
       rt |= RuntimeEffect::MetaData;
     if (auto *pa = dyn_cast<PartialApplyInst>(inst)) {
       if (!pa->isOnStack())

stdlib/public/core/Availability.swift

@@ -40,6 +40,7 @@ import SwiftShims
 #if os(iOS) && !os(visionOS)
 @_effects(readnone)
 @_transparent
+@_noLocks
 public func _stdlib_isOSVersionAtLeast(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,
@@ -51,6 +52,7 @@ public func _stdlib_isOSVersionAtLeast(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @_unavailableInEmbedded
+@_noLocks
 public func _stdlib_isOSVersionAtLeast(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,
@@ -63,6 +65,7 @@ public func _stdlib_isOSVersionAtLeast(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @_alwaysEmitIntoClient
+@_noLocks
 public func _stdlib_isOSVersionAtLeast_AEIC(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,
@@ -107,6 +110,7 @@ public func _stdlib_isOSVersionAtLeast_AEIC(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @available(macOS 10.15, iOS 13.0, *)
+@_noLocks
 public func _stdlib_isVariantOSVersionAtLeast(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,
@@ -149,6 +153,7 @@ public func _stdlib_isVariantOSVersionAtLeast(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @_unavailableInEmbedded
+@_noLocks
 public func _stdlib_isOSVersionAtLeastOrVariantVersionAtLeast(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,

stdlib/public/core/ErrorType.swift

@@ -181,6 +181,7 @@ public func _bridgeErrorToNSError(_ error: __owned Error) -> AnyObject
 @_silgen_name("swift_willThrowTypedImpl")
 @available(SwiftStdlib 6.0, *)
 @usableFromInline
+@_noLocks
 func _willThrowTypedImpl<E: Error>(_ error: E)
 
 #if !$Embedded

test/SILOptimizer/constant_propagation_availability.swift

@@ -62,7 +62,7 @@ public func testInlinable() -> Int {
 // CHECK-macosx10_14:  apply [[F]]
 // CHECK-macosx10_14: } // end sil function '$s33constant_propagation_availability27testAvailabilityPropagationSiyF'
 
-// CHECK-macosx10_14: sil [readnone] [_semantics "availability.osversion"] @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF
+// CHECK-macosx10_14: sil [no_locks] [readnone] [_semantics "availability.osversion"] @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF
 
 // CHECK-inlinable-LABEL: sil {{.*}} @$s4Test13testInlinableSiyF  : $@convention(thin) () -> Int {
 // CHECK-inlinable:  [[F:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF

test/SILOptimizer/performance-annotations.swift

@@ -125,6 +125,37 @@ func testCatch(_ b: Bool) throws -> Int? {
   }
 }
 
+enum ErrorEnum: Error {
+  case failed
+  case tryAgain
+}
+
+@_noLocks
+func concreteError(_ b: Bool) throws(ErrorEnum) -> Int {
+  if b {
+    return 28
+  }
+
+  throw .tryAgain
+}
+
+func concreteErrorOther(_ b: Bool) throws(ErrorEnum) -> Int {
+  if b {
+    return 28
+  }
+
+  throw .tryAgain
+}
+
+@_noLocks
+func testCatchConcrete(_ b: Bool) -> Int {
+  do {
+    return try concreteError(b) + concreteErrorOther(b)
+  } catch {
+    return 17
+  }
+}
+
 @_noLocks
 func testRecursion(_ i: Int) -> Int {
   if i > 0 {