[Noncopyable generics] Suppress inverse conformance mangling for more symbols

Don't mangle inverse conformances for symbols related to dispatch thunks,
protocol members, and other entities that are inexorably tied to the
primary definition of the type and must have stable names.

Extend the conditional suppression of inverse conformance mangling to
property descriptors and more conformance-related symbols.

(cherry picked from commit e1ee19a)

Author: DougGregor

lib/IRGen/IRGenMangler.cpp

@@ -214,6 +214,9 @@ std::string IRGenMangler::mangleProtocolConformanceDescriptor(
 
 std::string IRGenMangler::mangleProtocolConformanceDescriptorRecord(
                                  const RootProtocolConformance *conformance) {
+  llvm::SaveAndRestore X(AllowInverses,
+                         inversesAllowedIn(conformance->getDeclContext()));
+
   beginMangling();
   appendProtocolConformance(conformance);
   appendOperator("Hc");
@@ -222,6 +225,9 @@ std::string IRGenMangler::mangleProtocolConformanceDescriptorRecord(
 
 std::string IRGenMangler::mangleProtocolConformanceInstantiationCache(
                                  const RootProtocolConformance *conformance) {
+  llvm::SaveAndRestore X(AllowInverses,
+                         inversesAllowedIn(conformance->getDeclContext()));
+
   beginMangling();
   if (isa<NormalProtocolConformance>(conformance)) {
     appendProtocolConformance(conformance);
@@ -511,3 +517,17 @@ IRGenMangler::appendExtendedExistentialTypeShape(CanGenericSignature genSig,
   appendOperator(genSig ? "XG" : "Xg");
 }
 
+std::string
+IRGenMangler::mangleConformanceSymbol(Type type,
+                                      const ProtocolConformance *Conformance,
+                                      const char *Op) {
+llvm::SaveAndRestore X(AllowInverses,
+                       inversesAllowedIn(Conformance->getDeclContext()));
+
+  beginMangling();
+  if (type)
+    appendType(type, nullptr);
+  appendProtocolConformance(Conformance);
+  appendOperator(Op);
+  return finalize();
+}

lib/IRGen/IRGenMangler.h

@@ -46,6 +46,9 @@ class IRGenMangler : public Mangle::ASTMangler {
   IRGenMangler() { }
 
   std::string mangleDispatchThunk(const FuncDecl *func) {
+    // Dispatch thunks do not mangle inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendEntity(func);
     appendOperator("Tj");
@@ -55,6 +58,9 @@ class IRGenMangler : public Mangle::ASTMangler {
   std::string mangleDerivativeDispatchThunk(
       const AbstractFunctionDecl *func,
       AutoDiffDerivativeFunctionIdentifier *derivativeId) {
+    // Dispatch thunks do not mangle inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginManglingWithAutoDiffOriginalFunction(func);
     auto kind = Demangle::getAutoDiffFunctionKind(derivativeId->getKind());
     auto *resultIndices =
@@ -71,13 +77,19 @@ class IRGenMangler : public Mangle::ASTMangler {
 
   std::string mangleConstructorDispatchThunk(const ConstructorDecl *ctor,
                                              bool isAllocating) {
+    // Dispatch thunks do not mangle inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendConstructorEntity(ctor, isAllocating);
     appendOperator("Tj");
     return finalize();
   }
 
   std::string mangleMethodDescriptor(const FuncDecl *func) {
+    // Method descriptors do not mangle inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendEntity(func);
     appendOperator("Tq");
@@ -87,6 +99,9 @@ class IRGenMangler : public Mangle::ASTMangler {
   std::string mangleDerivativeMethodDescriptor(
       const AbstractFunctionDecl *func,
       AutoDiffDerivativeFunctionIdentifier *derivativeId) {
+    // Method descriptors do not mangle inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginManglingWithAutoDiffOriginalFunction(func);
     auto kind = Demangle::getAutoDiffFunctionKind(derivativeId->getKind());
     auto *resultIndices =
@@ -103,6 +118,9 @@ class IRGenMangler : public Mangle::ASTMangler {
 
   std::string mangleConstructorMethodDescriptor(const ConstructorDecl *ctor,
                                                 bool isAllocating) {
+    // Method descriptors do not mangle inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendConstructorEntity(ctor, isAllocating);
     appendOperator("Tq");
@@ -327,6 +345,10 @@ class IRGenMangler : public Mangle::ASTMangler {
     // among the type descriptors of different protocols.
     llvm::SaveAndRestore<bool> optimizeProtocolNames(OptimizeProtocolNames,
                                                      false);
+
+    // No mangling of inverse conformances inside protocols.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     bool isAssocTypeAtDepth = false;
     (void)appendAssocType(
@@ -341,6 +363,9 @@ class IRGenMangler : public Mangle::ASTMangler {
       const ProtocolDecl *proto,
       CanType subject,
       const ProtocolDecl *requirement) {
+    // No mangling of inverse conformances inside protocols.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendAnyGenericType(proto);
     if (isa<GenericTypeParamType>(subject)) {
@@ -357,6 +382,9 @@ class IRGenMangler : public Mangle::ASTMangler {
   std::string mangleBaseConformanceDescriptor(
       const ProtocolDecl *proto,
       const ProtocolDecl *requirement) {
+    // No mangling of inverse conformances inside protocols.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendAnyGenericType(proto);
     appendProtocolName(requirement);
@@ -368,6 +396,9 @@ class IRGenMangler : public Mangle::ASTMangler {
       const ProtocolDecl *proto,
       CanType subject,
       const ProtocolDecl *requirement) {
+    // No mangling of inverse conformances inside protocols.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendAnyGenericType(proto);
     bool isFirstAssociatedTypeIdentifier = true;
@@ -385,20 +416,27 @@ class IRGenMangler : public Mangle::ASTMangler {
                                     const RootProtocolConformance *conformance);
 
   std::string manglePropertyDescriptor(const AbstractStorageDecl *storage) {
+    llvm::SaveAndRestore X(AllowInverses, inversesAllowed(storage));
     beginMangling();
     appendEntity(storage);
     appendOperator("MV");
     return finalize();
   }
 
   std::string mangleFieldOffset(const ValueDecl *Decl) {
+    // No mangling of inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendEntity(Decl);
     appendOperator("Wvd");
     return finalize();
   }
 
   std::string mangleEnumCase(const ValueDecl *Decl) {
+    // No mangling of inverse conformances.
+    llvm::SaveAndRestore X(AllowInverses, false);
+
     beginMangling();
     appendEntity(Decl);
     appendOperator("WC");
@@ -716,14 +754,7 @@ class IRGenMangler : public Mangle::ASTMangler {
 
   std::string mangleConformanceSymbol(Type type,
                                       const ProtocolConformance *Conformance,
-                                      const char *Op) {
-    beginMangling();
-    if (type)
-      appendType(type, nullptr);
-    appendProtocolConformance(Conformance);
-    appendOperator(Op);
-    return finalize();
-  }
+                                      const char *Op);
 };
 
 /// Determines if the minimum deployment target's runtime demangler will not

test/IRGen/mangling_inverse_generics_evolution.swift

@@ -0,0 +1,27 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-ir -o - %s -module-name test \
+// RUN:   -enable-experimental-feature NoncopyableGenerics \
+// RUN:   -enable-experimental-feature NonescapableTypes \
+// RUN:   -parse-as-library \
+// RUN:   -enable-library-evolution \
+// RUN:   > %t/test.irgen
+
+// RUN: %FileCheck %s < %t/test.irgen
+
+public protocol P: ~Copyable { }
+
+public protocol Hello<Person>: ~Copyable {
+  // CHECK: @"$s4test5HelloP6PersonAC_AA1PTn"
+  // CHECK: @"$s6Person4test5HelloPTl" = alias
+  associatedtype Person: P & ~Copyable
+
+  // CHECK: @"$s4test5HelloP14favoritePerson0D0QzvrTq" = alias
+  var favoritePerson: Person { get }
+
+  // CHECK: @"$s4test5HelloP5greetyy6PersonQzFTq"
+  func greet(_ person: borrowing Person)
+}
+
+public struct Wrapper<T: ~Copyable> {
+  var wrapped: T { fatalError("boom") }
+}