Optimizer: add a preserveGenericSignature flag to FunctionPassContext.createSpecializedFunctionDeclaration

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/PassManager/FunctionPassContext.swift

@@ -137,14 +137,16 @@ struct FunctionPassContext : MutatingContext {
   func createSpecializedFunctionDeclaration(from original: Function, withName specializedFunctionName: String,
                                             withParams specializedParameters: [ParameterInfo],
                                             makeThin: Bool = false,
-                                            makeBare: Bool = false) -> Function
+                                            makeBare: Bool = false,
+                                            preserveGenericSignature: Bool = true) -> Function
   {
     return specializedFunctionName._withBridgedStringRef { nameRef in
       let bridgedParamInfos = specializedParameters.map { $0._bridged }
 
       return bridgedParamInfos.withUnsafeBufferPointer { paramBuf in
         bridgedPassContext.createSpecializedFunctionDeclaration(nameRef, paramBuf.baseAddress, paramBuf.count,
-                                                                original.bridged, makeThin, makeBare).function
+                                                                original.bridged, makeThin, makeBare,
+                                                                preserveGenericSignature).function
       }
     }
   }

include/swift/SILOptimizer/OptimizerBridging.h

@@ -265,7 +265,8 @@ struct BridgedPassContext {
                                                         SwiftInt paramCount,
                                                         BridgedFunction bridgedOriginal,
                                                         bool makeThin,
-                                                        bool makeBare) const;
+                                                        bool makeBare,
+                                                        bool preserveGenericSignature) const;
 
   bool completeLifetime(BridgedValue value) const;
 };

lib/SILOptimizer/Utils/OptimizerBridging.cpp

@@ -385,7 +385,8 @@ createSpecializedFunctionDeclaration(BridgedStringRef specializedName,
                                      SwiftInt paramCount,
                                      BridgedFunction bridgedOriginal,
                                      bool makeThin,
-                                     bool makeBare)  const {
+                                     bool makeBare,
+                                     bool preserveGenericSignature) const {
   auto *original = bridgedOriginal.getFunction();
   auto originalType = original->getLoweredFunctionType();
 
@@ -402,13 +403,14 @@ createSpecializedFunctionDeclaration(BridgedStringRef specializedName,
     extInfo = extInfo.withRepresentation(SILFunctionTypeRepresentation::Thin);
 
   auto ClonedTy = SILFunctionType::get(
-      originalType->getInvocationGenericSignature(), extInfo,
+      preserveGenericSignature ? originalType->getInvocationGenericSignature() : GenericSignature(),
+      extInfo,
       originalType->getCoroutineKind(),
       originalType->getCalleeConvention(), specializedParams,
       originalType->getYields(), originalType->getResults(),
       originalType->getOptionalErrorResult(),
-      originalType->getPatternSubstitutions(),
-      originalType->getInvocationSubstitutions(),
+      preserveGenericSignature ? originalType->getPatternSubstitutions() : SubstitutionMap(),
+      preserveGenericSignature ? originalType->getInvocationSubstitutions() : SubstitutionMap(),
       original->getModule().getASTContext());
 
   SILOptFunctionBuilder functionBuilder(*invocation->getTransform());
@@ -424,7 +426,8 @@ createSpecializedFunctionDeclaration(BridgedStringRef specializedName,
       // classes (the classSubclassScope), because that may incorrectly
       // influence the linkage.
       getSpecializedLinkage(original, original->getLinkage()), specializedName.unbridged(),
-      ClonedTy, original->getGenericEnvironment(),
+      ClonedTy,
+      preserveGenericSignature ? original->getGenericEnvironment() : nullptr,
       original->getLocation(), makeBare ? IsBare : original->isBare(), original->isTransparent(),
       original->getSerializedKind(), IsNotDynamic, IsNotDistributed,
       IsNotRuntimeAccessible, original->getEntryCount(),