Refactor remaining non-request usages of the GenericSignatureBuilder

include/swift/AST/GenericParamList.h

@@ -203,8 +203,6 @@ class RequirementRepr {
   void print(ASTPrinter &Printer) const;
 };
 
-using GenericParamSource = PointerUnion<GenericContext *, GenericParamList *>;
-
 /// GenericParamList - A list of generic parameters that is part of a generic
 /// function or type, along with extra requirements placed on those generic
 /// parameters and types derived from them.

include/swift/AST/TypeCheckRequests.h

@@ -459,6 +459,8 @@ struct WhereClauseOwner {
                      SpecializeAttr *, DifferentiableAttr *>
       source;
 
+  WhereClauseOwner() : dc(nullptr) {}
+
   WhereClauseOwner(GenericContext *genCtx);
   WhereClauseOwner(AssociatedTypeDecl *atd);
 
@@ -480,6 +482,10 @@ struct WhereClauseOwner {
     return llvm::hash_value(owner.source.getOpaqueValue());
   }
 
+  operator bool() const {
+    return dc != nullptr;
+  }
+
   friend bool operator==(const WhereClauseOwner &lhs,
                          const WhereClauseOwner &rhs) {
     return lhs.source.getOpaqueValue() == rhs.source.getOpaqueValue();
@@ -1437,11 +1443,12 @@ class AbstractGenericSignatureRequest :
 class InferredGenericSignatureRequest :
     public SimpleRequest<InferredGenericSignatureRequest,
                          GenericSignature (ModuleDecl *,
-                                            const GenericSignatureImpl *,
-                                            GenericParamSource,
-                                            SmallVector<Requirement, 2>,
-                                            SmallVector<TypeLoc, 2>,
-                                            bool),
+                                           const GenericSignatureImpl *,
+                                           GenericParamList *,
+                                           WhereClauseOwner,
+                                           SmallVector<Requirement, 2>,
+                                           SmallVector<TypeLoc, 2>,
+                                           bool),
                          RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -1452,9 +1459,10 @@ class InferredGenericSignatureRequest :
   // Evaluation.
   GenericSignature
   evaluate(Evaluator &evaluator,
-           ModuleDecl *module,
+           ModuleDecl *parentModule,
            const GenericSignatureImpl *baseSignature,
-           GenericParamSource paramSource,
+           GenericParamList *genericParams,
+           WhereClauseOwner whereClause,
            SmallVector<Requirement, 2> addedRequirements,
            SmallVector<TypeLoc, 2> inferenceSources,
            bool allowConcreteGenericParams) const;

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -131,10 +131,12 @@ SWIFT_REQUEST(TypeChecker, HasImplementationOnlyImportsRequest,
 SWIFT_REQUEST(TypeChecker, ModuleLibraryLevelRequest,
               LibraryLevel(ModuleDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InferredGenericSignatureRequest,
-              GenericSignature (ModuleDecl *, const GenericSignatureImpl *,
-                                 GenericParamSource,
-                                 SmallVector<Requirement, 2>,
-                                 SmallVector<TypeLoc, 2>, bool),
+              GenericSignature (ModuleDecl *,
+                                const GenericSignatureImpl *,
+                                GenericParamList *,
+                                WhereClauseOwner,
+                                SmallVector<Requirement, 2>,
+                                SmallVector<TypeLoc, 2>, bool),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, DistributedModuleIsAvailableRequest,
               bool(ModuleDecl *), Cached, NoLocationInfo)

include/swift/SILOptimizer/Analysis/DifferentiableActivityAnalysis.h

@@ -49,7 +49,6 @@
 #define SWIFT_SILOPTIMIZER_ANALYSIS_DIFFERENTIABLEACTIVITYANALYSIS_H_
 
 #include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/GenericSignatureBuilder.h"
 #include "swift/SIL/SILFunction.h"
 #include "swift/SIL/SILModule.h"
 #include "swift/SIL/SILValue.h"

lib/AST/GenericSignatureBuilder.cpp

@@ -8679,9 +8679,11 @@ AbstractGenericSignatureRequest::evaluate(
 
 GenericSignature
 InferredGenericSignatureRequest::evaluate(
-        Evaluator &evaluator, ModuleDecl *parentModule,
+        Evaluator &evaluator,
+        ModuleDecl *parentModule,
         const GenericSignatureImpl *parentSig,
-        GenericParamSource paramSource,
+        GenericParamList *genericParams,
+        WhereClauseOwner whereClause,
         SmallVector<Requirement, 2> addedRequirements,
         SmallVector<TypeLoc, 2> inferenceSources,
         bool allowConcreteGenericParams) const {
@@ -8729,12 +8731,6 @@ InferredGenericSignatureRequest::evaluate(
     return false;
   };
 
-  GenericParamList *genericParams = nullptr;
-  if (auto params = paramSource.dyn_cast<GenericParamList *>())
-      genericParams = params;
-  else
-      genericParams = paramSource.get<GenericContext *>()->getGenericParams();
-
   if (genericParams) {
     // Extensions never have a parent signature.
     if (genericParams->getOuterParameters())
@@ -8777,15 +8773,10 @@ InferredGenericSignatureRequest::evaluate(
     }
   }
 
-  if (auto *ctx = paramSource.dyn_cast<GenericContext *>()) {
-    // The declaration might have a trailing where clause.
-    if (auto *where = ctx->getTrailingWhereClause()) {
-      // Determine where and how to perform name lookup.
-      lookupDC = ctx;
-
-      WhereClauseOwner(lookupDC, where).visitRequirements(
+  if (whereClause) {
+    lookupDC = whereClause.dc;
+    std::move(whereClause).visitRequirements(
         TypeResolutionStage::Structural, visitRequirement);
-    }
   }
 
   /// Perform any remaining requirement inference.

lib/IRGen/GenType.h

@@ -34,7 +34,6 @@ namespace llvm {
 }
 
 namespace swift {
-  class GenericSignatureBuilder;
   class ArchetypeType;
   class CanType;
   class ClassDecl;

lib/IRGen/IRGenModule.h

@@ -85,7 +85,6 @@ namespace clang {
 
 namespace swift {
   class GenericSignature;
-  class GenericSignatureBuilder;
   class AssociatedConformance;
   class AssociatedType;
   class ASTContext;

lib/SILOptimizer/Differentiation/Thunk.cpp

@@ -20,9 +20,9 @@
 #include "swift/SILOptimizer/Differentiation/Common.h"
 
 #include "swift/AST/AnyFunctionRef.h"
-#include "swift/AST/GenericSignatureBuilder.h"
 #include "swift/AST/Requirement.h"
 #include "swift/AST/SubstitutionMap.h"
+#include "swift/AST/TypeCheckRequests.h"
 #include "swift/SILOptimizer/Utils/SILOptFunctionBuilder.h"
 #include "swift/SILOptimizer/Utils/DifferentiationMangler.h"
 
@@ -53,30 +53,26 @@ CanGenericSignature buildThunkSignature(SILFunction *fn, bool inheritGenericSig,
   }
 
   auto &ctx = fn->getASTContext();
-  GenericSignatureBuilder builder(ctx);
 
   // Add the existing generic signature.
+  GenericSignature baseGenericSig;
   int depth = 0;
   if (inheritGenericSig) {
-    if (auto genericSig =
-            fn->getLoweredFunctionType()->getSubstGenericSignature()) {
-      builder.addGenericSignature(genericSig);
-      depth = genericSig.getGenericParams().back()->getDepth() + 1;
-    }
+    baseGenericSig = fn->getLoweredFunctionType()->getSubstGenericSignature();
+    if (baseGenericSig)
+      depth = baseGenericSig.getGenericParams().back()->getDepth() + 1;
   }
 
   // Add a new generic parameter to replace the opened existential.
   auto *newGenericParam = GenericTypeParamType::get(depth, 0, ctx);
-
-  builder.addGenericParameter(newGenericParam);
   Requirement newRequirement(RequirementKind::Conformance, newGenericParam,
                              openedExistential->getOpenedExistentialType());
-  auto source =
-      GenericSignatureBuilder::FloatingRequirementSource::forAbstract();
-  builder.addRequirement(newRequirement, source, nullptr);
 
-  auto genericSig = std::move(builder).computeGenericSignature(
-      /*allowConcreteGenericParams=*/true);
+  auto genericSig = evaluateOrDefault(
+      ctx.evaluator,
+      AbstractGenericSignatureRequest{
+        baseGenericSig.getPointer(), { newGenericParam }, { newRequirement }},
+      GenericSignature());
   genericEnv = genericSig.getGenericEnvironment();
 
   newArchetype =

lib/Sema/TypeCheckAttr.cpp

@@ -25,7 +25,6 @@
 #include "swift/AST/DiagnosticsParse.h"
 #include "swift/AST/Effects.h"
 #include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/GenericSignatureBuilder.h"
 #include "swift/AST/ImportCache.h"
 #include "swift/AST/ModuleNameLookup.h"
 #include "swift/AST/NameLookup.h"
@@ -2231,28 +2230,17 @@ void AttributeChecker::visitSpecializeAttr(SpecializeAttr *attr) {
     return;
   }
 
-  // Form a new generic signature based on the old one.
-  GenericSignatureBuilder Builder(D->getASTContext());
+  InferredGenericSignatureRequest request{
+      DC->getParentModule(),
+      genericSig.getPointer(),
+      /*genericParams=*/nullptr,
+      WhereClauseOwner(FD, attr),
+      /*addedRequirements=*/{},
+      /*inferenceSources=*/{},
+      /*allowConcreteGenericParams=*/true};
 
-  // First, add the old generic signature.
-  Builder.addGenericSignature(genericSig);
-
-  // Go over the set of requirements, adding them to the builder.
-  WhereClauseOwner(FD, attr).visitRequirements(TypeResolutionStage::Interface,
-      [&](const Requirement &req, RequirementRepr *reqRepr) {
-        // Add the requirement to the generic signature builder.
-        using FloatingRequirementSource =
-          GenericSignatureBuilder::FloatingRequirementSource;
-        Builder.addRequirement(req, reqRepr,
-                               FloatingRequirementSource::forExplicit(
-                                 reqRepr->getSeparatorLoc()),
-                               nullptr, DC->getParentModule());
-        return false;
-      });
-
-  // Check the result.
-  auto specializedSig = std::move(Builder).computeGenericSignature(
-      /*allowConcreteGenericParams=*/true);
+  auto specializedSig = evaluateOrDefault(Ctx.evaluator, request,
+                                          GenericSignature());
 
   // Check the validity of provided requirements.
   checkSpecializeAttrRequirements(attr, genericSig, specializedSig, Ctx);
@@ -4266,7 +4254,8 @@ bool resolveDifferentiableAttrDerivativeGenericSignature(
   // - If the `@differentiable` attribute has a `where` clause, use it to
   //   compute the derivative generic signature.
   // - Otherwise, use the original function's generic signature by default.
-  derivativeGenSig = original->getGenericSignature();
+  auto originalGenSig = original->getGenericSignature();
+  derivativeGenSig = originalGenSig;
 
   // Handle the `where` clause, if it exists.
   // - Resolve attribute where clause requirements and store in the attribute
@@ -4291,7 +4280,6 @@ bool resolveDifferentiableAttrDerivativeGenericSignature(
       return true;
     }
 
-    auto originalGenSig = original->getGenericSignature();
     if (!originalGenSig) {
       // `where` clauses are valid only when the original function is generic.
       diags
@@ -4304,51 +4292,34 @@ bool resolveDifferentiableAttrDerivativeGenericSignature(
       return true;
     }
 
-    // Build a new generic signature for autodiff derivative functions.
-    GenericSignatureBuilder builder(ctx);
-    // Add the original function's generic signature.
-    builder.addGenericSignature(originalGenSig);
-
-    using FloatingRequirementSource =
-        GenericSignatureBuilder::FloatingRequirementSource;
-
-    bool errorOccurred = false;
-    WhereClauseOwner(original, attr)
-        .visitRequirements(
-            TypeResolutionStage::Structural,
-            [&](const Requirement &req, RequirementRepr *reqRepr) {
-              switch (req.getKind()) {
-              case RequirementKind::SameType:
-              case RequirementKind::Superclass:
-              case RequirementKind::Conformance:
-                break;
-
-              // Layout requirements are not supported.
-              case RequirementKind::Layout:
-                diags
-                    .diagnose(attr->getLocation(),
-                              diag::differentiable_attr_layout_req_unsupported)
-                    .highlight(reqRepr->getSourceRange());
-                errorOccurred = true;
-                return false;
-              }
+    InferredGenericSignatureRequest request{
+        original->getParentModule(),
+        originalGenSig.getPointer(),
+        /*genericParams=*/nullptr,
+        WhereClauseOwner(original, attr),
+        /*addedRequirements=*/{},
+        /*inferenceSources=*/{},
+        /*allowConcreteParams=*/true};
+
+    // Compute generic signature for derivative functions.
+    derivativeGenSig = evaluateOrDefault(ctx.evaluator, request,
+                                         GenericSignature());
 
-              // Add requirement to generic signature builder.
-              builder.addRequirement(
-                  req, reqRepr, FloatingRequirementSource::forExplicit(
-                    reqRepr->getSeparatorLoc()),
-                  nullptr, original->getModuleContext());
-              return false;
-            });
+    bool hadInvalidRequirements = false;
+    for (auto req : derivativeGenSig.requirementsNotSatisfiedBy(originalGenSig)) {
+      if (req.getKind() == RequirementKind::Layout) {
+        // Layout requirements are not supported.
+        diags
+            .diagnose(attr->getLocation(),
+                      diag::differentiable_attr_layout_req_unsupported);
+        hadInvalidRequirements = true;
+      }
+    }
 
-    if (errorOccurred) {
+    if (hadInvalidRequirements) {
       attr->setInvalid();
       return true;
     }
-
-    // Compute generic signature for derivative functions.
-    derivativeGenSig = std::move(builder).computeGenericSignature(
-        /*allowConcreteGenericParams=*/true);
   }
 
   attr->setDerivativeGenericSignature(derivativeGenSig);