Merge pull request #15888 from slavapestov/sil-link-fewer-vtables

Deserialize fewer vtables in -Onone

Author: slavapestov

lib/SIL/Linker.cpp

@@ -58,41 +58,11 @@ bool SILLinkerVisitor::processFunction(SILFunction *F) {
   return true;
 }
 
-/// Deserialize the VTable mapped to C if it exists and all SIL the VTable
-/// transitively references.
-///
-/// This method assumes that the caller made sure that no vtable existed in
-/// Mod.
-SILVTable *SILLinkerVisitor::processClassDecl(const ClassDecl *C) {
-  // If we are not linking anything, bail.
-  if (Mode == LinkingMode::LinkNone)
-    return nullptr;
-
-  // Attempt to load the VTable from the SerializedSILLoader. If we
-  // fail... bail...
-  SILVTable *Vtbl = Loader->lookupVTable(C);
-  if (!Vtbl)
-    return nullptr;
-
-  // Otherwise, add all the vtable functions in Vtbl to the function
-  // processing list...
-  for (auto &E : Vtbl->getEntries())
-    Worklist.push_back(E.Implementation);
-
-  // And then transitively deserialize all SIL referenced by those functions.
-  process();
-
-  // Return the deserialized Vtbl.
-  return Vtbl;
-}
-
+/// Deserialize the given VTable all SIL the VTable transitively references.
 bool SILLinkerVisitor::linkInVTable(ClassDecl *D) {
   // Attempt to lookup the Vtbl from the SILModule.
   SILVTable *Vtbl = Mod.lookUpVTable(D);
-
-  // If the SILModule does not have the VTable, attempt to deserialize the
-  // VTable. If we fail to do that as well, bail.
-  if (!Vtbl || !(Vtbl = Loader->lookupVTable(D->getName())))
+  if (!Vtbl)
     return false;
 
   // Ok we found our VTable. Visit each function referenced by the VTable. If
@@ -120,16 +90,17 @@ bool SILLinkerVisitor::visitApplyInst(ApplyInst *AI) {
     performFuncDeserialization |= visitApplySubstitutions(
       sig->getSubstitutionMap(AI->getSubstitutions()));
   }
-  
-  // Ok we have a function ref inst, grab the callee.
-  SILFunction *Callee = AI->getReferencedFunction();
-  if (!Callee)
-    return performFuncDeserialization;
 
-  if (isLinkAll() ||
-      hasSharedVisibility(Callee->getLinkage())) {
-    addFunctionToWorklist(Callee);
-    return true;
+  return performFuncDeserialization;
+}
+
+bool SILLinkerVisitor::visitTryApplyInst(TryApplyInst *TAI) {
+  bool performFuncDeserialization = false;
+
+  if (auto sig = TAI->getCallee()->getType().castTo<SILFunctionType>()
+                   ->getGenericSignature()) {
+    performFuncDeserialization |= visitApplySubstitutions(
+      sig->getSubstitutionMap(TAI->getSubstitutions()));
   }
 
   return performFuncDeserialization;
@@ -144,16 +115,6 @@ bool SILLinkerVisitor::visitPartialApplyInst(PartialApplyInst *PAI) {
       sig->getSubstitutionMap(PAI->getSubstitutions()));
   }
 
-  SILFunction *Callee = PAI->getReferencedFunction();
-  if (!Callee)
-    return performFuncDeserialization;
-
-  if (isLinkAll() ||
-      hasSharedVisibility(Callee->getLinkage())) {
-    addFunctionToWorklist(Callee);
-    return true;
-  }
-
   return performFuncDeserialization;
 }
 
@@ -353,6 +314,9 @@ bool SILLinkerVisitor::visitInitExistentialRefInst(
 }
 
 bool SILLinkerVisitor::visitAllocRefInst(AllocRefInst *ARI) {
+  if (!isLinkAll())
+    return false;
+
   // Grab the class decl from the alloc ref inst.
   ClassDecl *D = ARI->getType().getClassOrBoundGenericClass();
   if (!D)
@@ -362,6 +326,9 @@ bool SILLinkerVisitor::visitAllocRefInst(AllocRefInst *ARI) {
 }
 
 bool SILLinkerVisitor::visitMetatypeInst(MetatypeInst *MI) {
+  if (!isLinkAll())
+    return false;
+
   CanType instTy = MI->getType().castTo<MetatypeType>().getInstanceType();
   ClassDecl *C = instTy.getClassOrBoundGenericClass();
   if (!C)

lib/SIL/Linker.h

@@ -64,6 +64,7 @@ class SILLinkerVisitor : public SILInstructionVisitor<SILLinkerVisitor, bool> {
   bool visitSILInstruction(SILInstruction *I) { return false; }
 
   bool visitApplyInst(ApplyInst *AI);
+  bool visitTryApplyInst(TryApplyInst *TAI);
   bool visitPartialApplyInst(PartialApplyInst *PAI);
   bool visitFunctionRefInst(FunctionRefInst *FRI);
   bool visitProtocolConformance(ProtocolConformanceRef C,

lib/SIL/SILModule.cpp

@@ -614,9 +614,7 @@ SILVTable *SILModule::lookUpVTable(const ClassDecl *C) {
     return R->second;
 
   // If that fails, try to deserialize it. If that fails, return nullptr.
-  SILVTable *Vtbl =
-      SILLinkerVisitor(*this, getSILLoader(), SILModule::LinkingMode::LinkAll)
-          .processClassDecl(C);
+  SILVTable *Vtbl = getSILLoader()->lookupVTable(C);
   if (!Vtbl)
     return nullptr;
 

test/SIL/Serialization/Inputs/vtable_deserialization_input.swift

@@ -1,22 +1,11 @@
+public func unknown() {}
 
-public protocol P {
-  func doSomething()
-}
-
-@_silgen_name("unknown") public
-func unknown() -> ()
-
-@_fixed_layout
-public class Y : P {
-  @inlinable
-  public func doAnotherThing() {
+public class Class {
+  @inlinable public class func firstMethod() {
     unknown()
   }
 
-  @inlinable
-  public func doSomething() {
-    doAnotherThing()
-  }
-  @inlinable
-  public init() {}
+  @inlinable public class func secondMethod() {}
+
+  @inlinable public class func thirdMethod() {}
 }

test/SIL/Serialization/vtable_deserialization.swift

@@ -1,32 +1,42 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %S/Inputs/vtable_deserialization_input.swift -o %t/Swift.swiftmodule -emit-module -parse-as-library -parse-stdlib -module-link-name swiftCore -module-name Swift
-// RUN: %target-swift-frontend %s -emit-sil -O -I %t -o - | %FileCheck %s
-
-import Swift
-
-@usableFromInline
-@inlinable
-func WhatShouldIDoImBored<T : P>(_ t : T) {
-  t.doSomething()
-}
-
-@inline(__always)
-func MakeItNotAGlobal() -> Y {
-  let x = Y()
-  WhatShouldIDoImBored(x)
-  return x
-}
-
-
-// Make sure all abstractions have been removed and everything inlined into top_level_method.
-// CHECK-LABEL: sil @main
-// CHECK: bb0({{.*}}):
-// CHECK: [[UNKNOWN:%.*]] = function_ref @unknown
-// CHECK: apply [[UNKNOWN]]
-// CHECK: integer_literal
-// CHECK: return
-MakeItNotAGlobal()
-
-// Make sure our vtable/witness tables are properly deserialized.
-// CHECK: sil_vtable Y {
-// CHECK: sil_witness_table public_external Y: P module Swift {
+// RUN: %target-swift-frontend %S/Inputs/vtable_deserialization_input.swift -emit-module-path %t/vtable_deserialization_input.swiftmodule -emit-module
+// RUN: %target-swift-frontend %s -emit-sil -I %t | %FileCheck %s
+// RUN: %target-swift-frontend %s -emit-sil -O -I %t | %FileCheck %s --check-prefix=OPT
+
+import vtable_deserialization_input
+
+// Make sure we devirtualized the call and inlined the method body.
+// CHECK: function_ref @$S28vtable_deserialization_input5ClassC11firstMethodyyFZ
+// OPT: function_ref @$S28vtable_deserialization_input7unknownyyF
+Class.firstMethod()
+
+
+// For now, we also deserialize the body of firstMethod(), even though it
+// is not transparent.
+// CHECK-LABEL: sil public_external [serialized] @$S28vtable_deserialization_input5ClassC11firstMethodyyFZ : $@convention(method) (@thick Class.Type) -> () {
+// OPT-LABEL: sil public_external @$S28vtable_deserialization_input5ClassC11firstMethodyyFZ : $@convention(method) (@thick Class.Type) -> () {
+
+// The other two methods should not be deserialized in the mandatory
+// pipeline.
+
+// CHECK-LABEL: sil [serialized] @$S28vtable_deserialization_input5ClassC12secondMethodyyFZ : $@convention(method) (@thick Class.Type) -> (){{$}}
+// OPT-LABEL: sil public_external @$S28vtable_deserialization_input5ClassC12secondMethodyyFZ : $@convention(method) (@thick Class.Type) -> () {
+
+// CHECK-LABEL: sil [serialized] @$S28vtable_deserialization_input5ClassC11thirdMethodyyFZ : $@convention(method) (@thick Class.Type) -> (){{$}}
+// OPT-LABEL: sil public_external @$S28vtable_deserialization_input5ClassC11thirdMethodyyFZ : $@convention(method) (@thick Class.Type) -> () {
+
+// Make sure we deserialized the vtable.
+
+// CHECK:      sil_vtable [serialized] Class {
+// CHECK-NEXT:   #Class.firstMethod!1: (Class.Type) -> () -> () : @$S28vtable_deserialization_input5ClassC11firstMethodyyFZ
+// CHECK-NEXT:   #Class.secondMethod!1: (Class.Type) -> () -> () : @$S28vtable_deserialization_input5ClassC12secondMethodyyFZ
+// CHECK-NEXT:   #Class.thirdMethod!1: (Class.Type) -> () -> () : @$S28vtable_deserialization_input5ClassC11thirdMethodyyFZ
+// CHECK-NEXT:   #Class.deinit!deallocator: @$S28vtable_deserialization_input5ClassCfD
+// CHECK-NEXT: }
+
+// OPT:      sil_vtable Class {
+// OPT-NEXT:   #Class.firstMethod!1: (Class.Type) -> () -> () : @$S28vtable_deserialization_input5ClassC11firstMethodyyFZ
+// OPT-NEXT:   #Class.secondMethod!1: (Class.Type) -> () -> () : @$S28vtable_deserialization_input5ClassC12secondMethodyyFZ
+// OPT-NEXT:   #Class.thirdMethod!1: (Class.Type) -> () -> () : @$S28vtable_deserialization_input5ClassC11thirdMethodyyFZ
+// OPT-NEXT:   #Class.deinit!deallocator: @$S28vtable_deserialization_input5ClassCfD
+// OPT-NEXT: }