[NFC] GenericRequirement vends an llvm::Type *.

The mapping from requirement kind to llvm::Type is repeated several
places.  Pull it into a helper.

Author: nate-chandler

include/swift/IRGen/GenericRequirement.h

@@ -17,9 +17,16 @@
 #include "swift/AST/Type.h"
 #include "llvm/Support/raw_ostream.h"
 
+namespace llvm {
+class Type;
+}
+
 namespace swift {
 
 class ProtocolDecl;
+namespace irgen {
+class IRGenModule;
+}
 
 /// The three kinds of entities passed in the runtime calling convention for
 /// generic code: pack shapes, type metadata, and witness tables.
@@ -87,6 +94,13 @@ class GenericRequirement {
     return GenericRequirement(Kind::WitnessTable, type, proto);
   }
 
+  static llvm::Type *typeForKind(irgen::IRGenModule &IGM,
+                                 GenericRequirement::Kind kind);
+
+  llvm::Type *getType(irgen::IRGenModule &IGM) const {
+    return typeForKind(IGM, getKind());
+  }
+
   void dump(llvm::raw_ostream &out) const {
     switch (kind) {
     case Kind::Shape:

lib/IRGen/GenMeta.cpp

@@ -3898,13 +3898,11 @@ namespace {
                                ClassDecl *forClass) {
       switch (requirement.getKind()) {
       case GenericRequirement::Kind::Shape:
-        B.addInt(IGM.SizeTy, 0);
+        B.addInt(cast<llvm::IntegerType>(requirement.getType(IGM)), 0);
         break;
       case GenericRequirement::Kind::Metadata:
-        B.addNullPointer(IGM.TypeMetadataPtrTy);
-        break;
       case GenericRequirement::Kind::WitnessTable:
-        B.addNullPointer(IGM.WitnessTablePtrTy);
+        B.addNullPointer(cast<llvm::PointerType>(requirement.getType(IGM)));
         break;
       }
     }

lib/IRGen/GenProto.cpp

@@ -3600,24 +3600,27 @@ void irgen::bindFromGenericRequirementsBuffer(IRGenFunction &IGF,
     }
 
     // Cast if necessary.
-    switch (requirements[index].getKind()) {
-    case GenericRequirement::Kind::Shape:
-      slot = IGF.Builder.CreateElementBitCast(slot, IGF.IGM.SizeTy);
-      break;
-    case GenericRequirement::Kind::Metadata:
-      slot = IGF.Builder.CreateElementBitCast(slot, IGF.IGM.TypeMetadataPtrTy);
-      break;
-    case GenericRequirement::Kind::WitnessTable:
-      slot = IGF.Builder.CreateElementBitCast(slot, IGF.IGM.WitnessTablePtrTy);
-      break;
-    }
+    slot = IGF.Builder.CreateElementBitCast(
+        slot, requirements[index].getType(IGF.IGM));
 
     llvm::Value *value = IGF.Builder.CreateLoad(slot);
     bindGenericRequirement(IGF, requirements[index], value, metadataState,
                            getInContext);
   }
 }
 
+llvm::Type *GenericRequirement::typeForKind(IRGenModule &IGM,
+                                            GenericRequirement::Kind kind) {
+  switch (kind) {
+  case GenericRequirement::Kind::Shape:
+    return IGM.SizeTy;
+  case GenericRequirement::Kind::Metadata:
+    return IGM.TypeMetadataPtrTy;
+  case GenericRequirement::Kind::WitnessTable:
+    return IGM.WitnessTablePtrTy;
+  }
+}
+
 void irgen::bindGenericRequirement(IRGenFunction &IGF,
                                    GenericRequirement requirement,
                                    llvm::Value *value,
@@ -3626,17 +3629,16 @@ void irgen::bindGenericRequirement(IRGenFunction &IGF,
   // Get the corresponding context type.
   auto type = getInContext(requirement.getTypeParameter());
 
+  assert(value->getType() == requirement.getType(IGF.IGM));
   switch (requirement.getKind()) {
   case GenericRequirement::Kind::Shape: {
     assert(isa<ArchetypeType>(type));
-    assert(value->getType() == IGF.IGM.SizeTy);
     auto kind = LocalTypeDataKind::forPackShapeExpression();
     IGF.setUnscopedLocalTypeData(type, kind, value);
     break;
   }
 
   case GenericRequirement::Kind::Metadata: {
-    assert(value->getType() == IGF.IGM.TypeMetadataPtrTy);
     setTypeMetadataName(IGF.IGM, value, type);
     IGF.bindLocalTypeDataFromTypeMetadata(type, IsExact, value, metadataState);
     break;
@@ -3645,7 +3647,6 @@ void irgen::bindGenericRequirement(IRGenFunction &IGF,
   case GenericRequirement::Kind::WitnessTable: {
     auto proto = requirement.getProtocol();
     assert(isa<ArchetypeType>(type));
-    assert(value->getType() == IGF.IGM.WitnessTablePtrTy);
     setProtocolWitnessTableName(IGF.IGM, value, type, proto);
     auto kind = LocalTypeDataKind::forAbstractProtocolWitnessTable(proto);
     IGF.setUnscopedLocalTypeData(type, kind, value);
@@ -3676,17 +3677,15 @@ namespace {
       enumerateUnfulfilledRequirements([&](GenericRequirement reqt) {
         if (reqs)
           reqs->push_back(reqt);
+        out.push_back(reqt.getType(IGM));
         switch (reqt.getKind()) {
         case GenericRequirement::Kind::Shape:
-          out.push_back(IGM.SizeTy);
           ++numShapes;
           break;
         case GenericRequirement::Kind::Metadata:
-          out.push_back(IGM.TypeMetadataPtrTy);
           ++numTypeMetadataPtrs;
           break;
         case GenericRequirement::Kind::WitnessTable:
-          out.push_back(IGM.WitnessTablePtrTy);
           ++numWitnessTablePtrs;
           break;
         }

lib/IRGen/GenericArguments.h

@@ -59,17 +59,7 @@ struct GenericArguments {
   void collectTypes(IRGenModule &IGM,
                     const GenericTypeRequirements &requirements) {
     for (auto &requirement : requirements.getRequirements()) {
-      switch (requirement.getKind()) {
-      case GenericRequirement::Kind::Shape:
-        Types.push_back(IGM.SizeTy);
-        break;
-      case GenericRequirement::Kind::Metadata:
-        Types.push_back(IGM.TypeMetadataPtrTy);
-        break;
-      case GenericRequirement::Kind::WitnessTable:
-        Types.push_back(IGM.WitnessTablePtrTy);
-        break;
-      }
+      Types.push_back(requirement.getType(IGM));
     }
   }