Eliminate dead code making use of SubstitutionList.

Author: DougGregor

include/swift/AST/Types.h

@@ -3055,10 +3055,6 @@ class GenericFunctionType final : public AnyFunctionType,
   /// Retrieve the requirements of this polymorphic function type.
   ArrayRef<Requirement> getRequirements() const;
 
-  /// Substitute the given generic arguments into this generic
-  /// function type and return the resulting non-generic type.
-  FunctionType *substGenericArgs(SubstitutionList subs);
-
   /// Substitute the given generic arguments into this generic
   /// function type and return the resulting non-generic type.
   FunctionType *substGenericArgs(const SubstitutionMap &subs);
@@ -4036,8 +4032,6 @@ class SILFunctionType final : public TypeBase, public llvm::FoldingSetNode,
   ABICompatibilityCheckResult
   isABICompatibleWith(CanSILFunctionType other) const;
 
-  CanSILFunctionType substGenericArgs(SILModule &silModule,
-                                      SubstitutionList subs);
   CanSILFunctionType substGenericArgs(SILModule &silModule,
                                       const SubstitutionMap &subs);
   CanSILFunctionType substGenericArgs(SILModule &silModule,

include/swift/SIL/SILInstruction.h

@@ -1792,9 +1792,6 @@ class ApplyInstBase<Impl, Base, false> : public Base {
     return Substitutions.hasAnySubstitutableParams();
   }
 
-  /// The substitutions used to bind the generic arguments of this function.
-  SubstitutionList getSubstitutions() const { return Substitutions.toList(); }
-
   /// The substitutions used to bind the generic arguments of this function.
   SubstitutionMap getSubstitutionMap() const { return Substitutions; }
 
@@ -1892,7 +1889,6 @@ class ApplyInstBase<Impl, Base, true>
   using super::getSubstCalleeType;
   using super::getSubstCalleeConv;
   using super::hasSubstitutions;
-  using super::getSubstitutions;
   using super::getNumArguments;
   using super::getArgument;
   using super::getArguments;
@@ -7700,26 +7696,11 @@ class ApplySite {
     FOREACH_IMPL_RETURN(hasSubstitutions());
   }
 
-  /// The substitutions used to bind the generic arguments of this function.
-  SubstitutionList getSubstitutions() const {
-    FOREACH_IMPL_RETURN(getSubstitutions());
-  }
-
   /// The substitutions used to bind the generic arguments of this function.
   SubstitutionMap getSubstitutionMap() const {
     FOREACH_IMPL_RETURN(getSubstitutionMap());
   }
 
-  /// Return a begin iterator for the substitution array.
-  auto subs_begin() const -> decltype(getSubstitutions().begin()) {
-    return getSubstitutions().begin();
-  }
-
-  /// Return an end iterator for the substitution array.
-  auto subs_end() const -> decltype(getSubstitutions().end()) {
-    return getSubstitutions().end();
-  }
-
   /// The arguments passed to this instruction.
   MutableArrayRef<Operand> getArgumentOperands() const {
     FOREACH_IMPL_RETURN(getArgumentOperands());

include/swift/SIL/SILType.h

@@ -434,13 +434,6 @@ class SILType {
     return SILType(getASTType().getReferenceStorageReferent(), getCategory());
   }
 
-  /// Transform the function type SILType by replacing all of its interface
-  /// generic args with the appropriate item from the substitution.
-  ///
-  /// Only call this with function types!
-  SILType substGenericArgs(SILModule &M,
-                           SubstitutionList Subs) const;
-
   /// Transform the function type SILType by replacing all of its interface
   /// generic args with the appropriate item from the substitution.
   ///

lib/AST/Type.cpp

@@ -2765,11 +2765,6 @@ bool AnyFunctionType::isCanonicalFunctionInputType(Type input) {
   return isa<TypeVariableType>(input.getPointer());
 }
 
-FunctionType *
-GenericFunctionType::substGenericArgs(SubstitutionList args) {
-  return substGenericArgs(getGenericSignature()->getSubstitutionMap(args));
-}
-
 FunctionType *
 GenericFunctionType::substGenericArgs(const SubstitutionMap &subs) {
   Type input = getInput().subst(subs);

lib/SIL/SILFunctionType.cpp

@@ -2451,23 +2451,6 @@ SILType SILType::subst(SILModule &silModule, const SubstitutionMap &subs) const{
                LookUpConformanceInSubstitutionMap(subs));
 }
 
-/// Apply a substitution to this polymorphic SILFunctionType so that
-/// it has the form of the normal SILFunctionType for the substituted
-/// type, except using the original conventions.
-CanSILFunctionType
-SILFunctionType::substGenericArgs(SILModule &silModule,
-                                  SubstitutionList subs) {
-  if (subs.empty()) {
-    assert(
-        (!isPolymorphic() || getGenericSignature()->areAllParamsConcrete()) &&
-        "no args for non-concrete polymorphic substitution");
-    return CanSILFunctionType(this);
-  }
-
-  auto subMap = GenericSig->getSubstitutionMap(subs);
-  return substGenericArgs(silModule, subMap);
-}
-
 /// Apply a substitution to this polymorphic SILFunctionType so that
 /// it has the form of the normal SILFunctionType for the substituted
 /// type, except using the original conventions.

lib/SIL/SILType.cpp

@@ -178,13 +178,6 @@ bool SILType::isAddressOnly(SILModule &M) const {
   return M.getTypeLowering(*this).isAddressOnly();
 }
 
-SILType SILType::substGenericArgs(SILModule &M,
-                                  SubstitutionList Subs) const {
-  auto fnTy = castTo<SILFunctionType>();
-  auto canFnTy = CanSILFunctionType(fnTy->substGenericArgs(M, Subs));
-  return SILType::getPrimitiveObjectType(canFnTy);
-}
-
 SILType SILType::substGenericArgs(SILModule &M,
                                   const SubstitutionMap &SubMap) const {
   auto fnTy = castTo<SILFunctionType>();

lib/SIL/SILVerifier.cpp

@@ -1081,8 +1081,8 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
     };
 
     // Search for opened archetypes and dynamic self.
-    for (auto &Sub : AS.getSubstitutions()) {
-      Sub.getReplacement()->getCanonicalType().visit(HandleType);
+    for (auto Replacement : AS.getSubstitutionMap().getReplacementTypes()) {
+      Replacement->getCanonicalType().visit(HandleType);
     }
     AS.getSubstCalleeType().visit(HandleType);
 

lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp

@@ -805,8 +805,7 @@ SILCombiner::createApplyWithConcreteType(FullApplySite AI,
   // replaced by a concrete type.
   SubstitutionMap Substitutions;
   if (FnTy->isPolymorphic()) {
-    auto FnSubsMap =
-        FnTy->getGenericSignature()->getSubstitutionMap(AI.getSubstitutions());
+    auto FnSubsMap = AI.getSubstitutionMap();
     Substitutions = FnSubsMap.subst(
         [&](SubstitutableType *type) -> Type {
           if (type == OpenedArchetype)

lib/SILOptimizer/Transforms/CSE.cpp

@@ -1043,7 +1043,8 @@ static bool tryToCSEOpenExtCall(OpenExistentialAddrInst *From,
          "Invalid number of arguments");
 
   // Don't handle any apply instructions that involve substitutions.
-  if (ToAI->getSubstitutions().size() != 1) return false;
+  if (ToAI->getSubstitutionMap().getReplacementTypes().size() != 1)
+    return false;
 
   // Prepare the Apply args.
   SmallVector<SILValue, 8> Args;

lib/SILOptimizer/Transforms/FunctionSignatureOpts.cpp

@@ -285,9 +285,9 @@ static bool usesGenerics(SILFunction *F,
       }
       // Scan all substitutions of apply instructions.
       if (auto AI = ApplySite::isa(&I)) {
-        auto Subs = AI.getSubstitutions();
-        for (auto Sub : Subs) {
-          Sub.getReplacement().visit(FindArchetypesAndGenericTypes);
+        auto Subs = AI.getSubstitutionMap();
+        for (auto Replacement : Subs.getReplacementTypes()) {
+          Replacement.visit(FindArchetypesAndGenericTypes);
         }
       }
       // Scan all substitutions of builtin instructions.

lib/SILOptimizer/Transforms/PerformanceInliner.cpp

@@ -475,7 +475,7 @@ bool SILPerformanceInliner::isProfitableToInline(
 /// It returns None if the decision cannot be made without a more complex
 /// analysis.
 static Optional<bool> shouldInlineGeneric(FullApplySite AI) {
-  assert(!AI.getSubstitutions().empty() &&
+  assert(AI.hasSubstitutions() &&
          "Expected a generic apply");
 
   SILFunction *Callee = AI.getReferencedFunction();
@@ -516,7 +516,7 @@ bool SILPerformanceInliner::decideInWarmBlock(
     FullApplySite AI, Weight CallerWeight, ConstantTracker &callerTracker,
     int &NumCallerBlocks,
     const llvm::DenseMap<SILBasicBlock *, uint64_t> &BBToWeightMap) {
-  if (!AI.getSubstitutions().empty()) {
+  if (AI.hasSubstitutions()) {
     // Only inline generics if definitively clear that it should be done.
     auto ShouldInlineGeneric = shouldInlineGeneric(AI);
     if (ShouldInlineGeneric.hasValue())
@@ -540,7 +540,7 @@ bool SILPerformanceInliner::decideInWarmBlock(
 /// Return true if inlining this call site into a cold block is profitable.
 bool SILPerformanceInliner::decideInColdBlock(FullApplySite AI,
                                               SILFunction *Callee) {
-  if (!AI.getSubstitutions().empty()) {
+  if (AI.hasSubstitutions()) {
     // Only inline generics if definitively clear that it should be done.
     auto ShouldInlineGeneric = shouldInlineGeneric(AI);
     if (ShouldInlineGeneric.hasValue())

lib/SILOptimizer/Utils/Devirtualize.cpp

@@ -441,9 +441,7 @@ getSubstitutionsForCallee(SILModule &M,
         M.getSwiftModule(), baseClassDecl);
   }
 
-  SubstitutionMap origSubMap;
-  if (auto origCalleeSig = AI.getOrigCalleeType()->getGenericSignature())
-    origSubMap = origCalleeSig->getSubstitutionMap(AI.getSubstitutions());
+  SubstitutionMap origSubMap = AI.getSubstitutionMap();
 
   Type calleeSelfType = AI.getOrigCalleeType()->getSelfParameter().getType();
   if (auto metatypeType = calleeSelfType->getAs<MetatypeType>())

lib/SILOptimizer/Utils/Generics.cpp

@@ -290,9 +290,8 @@ static bool createsInfiniteSpecializationLoop(ApplySite Apply) {
                      << "Caller: " << Caller->getName() << "\n"
                      << "Callee: " << Callee->getName() << "\n";
         llvm::dbgs() << "Substitutions:\n";
-        for (auto Sub: Apply.getSubstitutions()) {
-          Sub.getReplacement()->dump();
-        });
+        Apply.getSubstitutionMap().dump(llvm::dbgs());
+        );
 
   auto *CurSpecializationInfo = Apply.getSpecializationInfo();
   if (CurSpecializationInfo) {

lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp

@@ -560,12 +560,12 @@ static bool calleeHasPartialApplyWithOpenedExistentials(FullApplySite AI) {
     return false;
 
   SILFunction *Callee = AI.getReferencedFunction();
-  auto Subs = AI.getSubstitutions();
+  auto SubsMap = AI.getSubstitutionMap();
 
   // Bail if there are no open existentials in the list of substitutions.
   bool HasNoOpenedExistentials = true;
-  for (auto Sub : Subs) {
-    if (Sub.getReplacement()->hasOpenedExistential()) {
+  for (auto Replacement : SubsMap.getReplacementTypes()) {
+    if (Replacement->hasOpenedExistential()) {
       HasNoOpenedExistentials = false;
       break;
     }
@@ -574,9 +574,6 @@ static bool calleeHasPartialApplyWithOpenedExistentials(FullApplySite AI) {
   if (HasNoOpenedExistentials)
     return false;
 
-  auto SubsMap = Callee->getLoweredFunctionType()
-    ->getGenericSignature()->getSubstitutionMap(Subs);
-
   for (auto &BB : *Callee) {
     for (auto &I : BB) {
       if (auto PAI = dyn_cast<PartialApplyInst>(&I)) {
@@ -630,7 +627,7 @@ static bool isCallerAndCalleeLayoutConstraintsCompatible(FullApplySite AI) {
   SILFunction *Callee = AI.getReferencedFunction();
   auto CalleeSig = Callee->getLoweredFunctionType()->getGenericSignature();
   auto SubstParams = CalleeSig->getSubstitutableParams();
-  auto AISubs = AI.getSubstitutions();
+  auto AISubs = AI.getSubstitutionMap();
   for (auto idx : indices(SubstParams)) {
     auto Param = SubstParams[idx];
     // Map the parameter into context
@@ -643,7 +640,7 @@ static bool isCallerAndCalleeLayoutConstraintsCompatible(FullApplySite AI) {
       continue;
     // The generic parameter has a layout constraint.
     // Check that the substitution has the same constraint.
-    auto AIReplacement = AISubs[idx].getReplacement();
+    auto AIReplacement = Type(Param).subst(AISubs);
     auto AIArchetype = AIReplacement->getAs<ArchetypeType>();
     if (!AIArchetype)
       return false;