Fix for extensions in ProtocolConformanceAnalysis

Author: Raj Barik

lib/SILOptimizer/Analysis/ProtocolConformanceAnalysis.cpp

@@ -17,6 +17,7 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/Module.h"
+#include "swift/AST/ProtocolConformance.h"
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILModule.h"
 #include "swift/SIL/SILValue.h"
@@ -34,6 +35,7 @@ class NominalTypeWalker : public ASTWalker {
       : ProtocolConformanceCache(ProtocolConformanceCache) {}
 
   bool walkToDeclPre(Decl *D) override {
+    /// (1) Walk over all NominalTypeDecls to determine conformances.
     if (auto *NTD = dyn_cast<NominalTypeDecl>(D)) {
       auto Protocols = NTD->getAllProtocols();
       for (auto &Protocol : Protocols) {
@@ -42,6 +44,20 @@ class NominalTypeWalker : public ASTWalker {
         }
       }
     }
+    /// (2) Walk over all ExtensionDecls to determine conformances.
+    if (auto *e = dyn_cast<ExtensionDecl>(D)) {
+      auto *ntd = e->getExtendedNominal();
+      if (!isa<ProtocolDecl>(ntd)) {
+        for (auto *conformance : e->getLocalConformances()) {
+          if (isa<NormalProtocolConformance>(conformance)) {
+            auto *proto = conformance->getProtocol();
+            if (proto->getEffectiveAccess() <= AccessLevel::Internal) {
+              ProtocolConformanceCache[proto].push_back(ntd);
+            }
+          }
+        }
+      }
+    }
     return true;
   }
 };

test/Interpreter/existential_transform.swift

@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift -O -wmo %s -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+// REQUIRES: executable_test
+
+protocol Foo {
+  var myName: String { get }
+}
+
+struct MyURL {
+}
+
+extension MyURL : Foo {
+  var myName : String { return "MyURL" }
+}
+
+struct MyStruct : Foo {
+  var myName : String { return "MyStruct" }
+}
+
+@inline(never) func getName(_ f: Foo) -> String {
+  return f.myName
+}
+
+@inline(never) func getName_wrapper() {
+  let u = MyURL()
+  // CHECK: MyURL
+  print(getName(u))
+}
+getName_wrapper()
+

test/SILOptimizer/existential_transform.swift

@@ -358,6 +358,42 @@ func wrap_gcp_arch<T:GP>(_ a:T,_ b:GP, _ c:inout Array<T>) -> Int {
   return wrap_gcp_arch(a, k, &b)
 }
 
+protocol Foo {
+  var myName: String { get }
+}
+
+struct MyURL {
+}
+
+extension MyURL : Foo {
+  var myName : String { return "MyURL" }
+}
+
+struct MyStruct : Foo {
+  var myName : String { return "MyStruct" }
+}
+
+// CHECK-LABEL: sil shared [noinline] @$s21existential_transform7getNameySSAA3Foo_pFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : Foo> (@in_guaranteed τ_0_0) -> @owned String {
+// CHECK: bb0(%0 : $*τ_0_0):
+// CHECK:   alloc_stack
+// CHECK:   init_existential_addr
+// CHECK:   copy_addr
+// CHECK:   debug_value_addr 
+// CHECK:   open_existential_addr
+// CHECK:   witness_method 
+// CHECK:   apply
+// CHECK:   dealloc_stack
+// CHECK:   return
+// CHECK-LABEL: } // end sil function '$s21existential_transform7getNameySSAA3Foo_pFTf4e_n'
+@inline(never) func getName(_ f: Foo) -> String {
+  return f.myName
+}
+
+@inline(never) func getName_wrapper() -> Int32{
+  let u = MyURL()
+  return getName(u) == "MyStruct" ? 0 : 1
+}
+
 @_optimize(none) public func foo() -> Int {
 cp()
 ncp()
@@ -371,5 +407,6 @@ struct_inout_ncp()
 let y:Int = gcp(GC())
 var a:Array<GC> = [GC()]
 let z:Int = gcp_arch(GC(), &a) 
-return x + y + z
+let zz:Int32 = getName_wrapper()
+return x + y + z + Int(zz)
 }