[NFC] Extracted emitPackExpansionPack.

Author: nate-chandler

lib/IRGen/GenPack.cpp

@@ -345,11 +345,14 @@ static llvm::Value *emitPackExpansionElementMetadata(
   return element;
 }
 
-static void emitPackExpansionType(IRGenFunction &IGF, Address pack,
-                                  CanPackExpansionType expansionTy,
-                                  llvm::Value *dynamicIndex,
-                                  llvm::Value *dynamicLength,
-                                  DynamicMetadataRequest request) {
+/// Store the values corresponding to the specified pack expansion \p
+/// expansionTy for each index in its range [dynamicIndex, dynamicIndex +
+/// dynamicLength) produced by the provided function \p elementForIndex into
+/// the indicated buffer \p pack.
+static void emitPackExpansionPack(
+    IRGenFunction &IGF, Address pack, CanPackExpansionType expansionTy,
+    llvm::Value *dynamicIndex, llvm::Value *dynamicLength,
+    function_ref<llvm::Value *(llvm::Value *)> elementForIndex) {
   auto *prev = IGF.Builder.GetInsertBlock();
   auto *check = IGF.createBasicBlock("pack-expansion-check");
   auto *loop = IGF.createBasicBlock("pack-expansion-loop");
@@ -368,8 +371,7 @@ static void emitPackExpansionType(IRGenFunction &IGF, Address pack,
 
   IGF.Builder.emitBlock(loop);
 
-  auto *element =
-      emitPackExpansionElementMetadata(IGF, expansionTy, phi, request);
+  auto *element = elementForIndex(phi);
 
   // Store the element metadata into to the current destination index.
   auto *eltIndex = IGF.Builder.CreateAdd(dynamicIndex, phi);
@@ -395,6 +397,18 @@ static void emitPackExpansionType(IRGenFunction &IGF, Address pack,
   IGF.Builder.emitBlock(rest);
 }
 
+static void emitPackExpansionMetadataPack(IRGenFunction &IGF, Address pack,
+                                          CanPackExpansionType expansionTy,
+                                          llvm::Value *dynamicIndex,
+                                          llvm::Value *dynamicLength,
+                                          DynamicMetadataRequest request) {
+  emitPackExpansionPack(IGF, pack, expansionTy, dynamicIndex, dynamicLength,
+                        [&](auto *index) {
+                          return emitPackExpansionElementMetadata(
+                              IGF, expansionTy, index, request);
+                        });
+}
+
 StackAddress
 irgen::emitTypeMetadataPack(IRGenFunction &IGF,
                             CanPackType packType,
@@ -421,8 +435,8 @@ irgen::emitTypeMetadataPack(IRGenFunction &IGF,
       }
 
       if (auto expansionTy = dyn_cast<PackExpansionType>(eltTy)) {
-        emitPackExpansionType(IGF, pack.getAddress(), expansionTy,
-                              dynamicIndex, dynamicLength, request);
+        emitPackExpansionMetadataPack(IGF, pack.getAddress(), expansionTy,
+                                      dynamicIndex, dynamicLength, request);
       } else {
         Address eltPtr(
           IGF.Builder.CreateInBoundsGEP(pack.getAddress().getElementType(),
@@ -508,52 +522,17 @@ static llvm::Value *emitPackExpansionElementWitnessTable(
   return wtable;
 }
 
-static void emitExpansionWitnessTablePack(IRGenFunction &IGF, Address pack,
-                                          CanPackExpansionType expansionTy,
-                                          ProtocolConformanceRef conformance,
-                                          llvm::Value *dynamicIndex,
-                                          llvm::Value *dynamicLength) {
-  auto *prev = IGF.Builder.GetInsertBlock();
-  auto *check = IGF.createBasicBlock("pack-expansion-check");
-  auto *loop = IGF.createBasicBlock("pack-expansion-loop");
-  auto *rest = IGF.createBasicBlock("pack-expansion-rest");
-
-  IGF.Builder.CreateBr(check);
-  IGF.Builder.emitBlock(check);
-
-  // An index into the source witness table pack.
-  auto *phi = IGF.Builder.CreatePHI(IGF.IGM.SizeTy, 2);
-  phi->addIncoming(llvm::ConstantInt::get(IGF.IGM.SizeTy, 0), prev);
-
-  // If we reach the end, jump to the continuation block.
-  auto *cond = IGF.Builder.CreateICmpULT(phi, dynamicLength);
-  IGF.Builder.CreateCondBr(cond, loop, rest);
-
-  IGF.Builder.emitBlock(loop);
-
-  llvm::Value *_metadata = nullptr;
-  auto *element = emitPackExpansionElementWitnessTable(
-      IGF, expansionTy, conformance, /*srcMetadataCache=*/&_metadata, phi);
-
-  // Store the element witness table into to the current destination index.
-  auto *eltIndex = IGF.Builder.CreateAdd(dynamicIndex, phi);
-  Address eltPtr(IGF.Builder.CreateInBoundsGEP(pack.getElementType(),
-                                               pack.getAddress(), eltIndex),
-                 pack.getElementType(), pack.getAlignment());
-
-  IGF.Builder.CreateStore(element, eltPtr);
-
-  // Increment our counter.
-  auto *next =
-      IGF.Builder.CreateAdd(phi, llvm::ConstantInt::get(IGF.IGM.SizeTy, 1));
-
-  phi->addIncoming(next, loop);
-
-  // Repeat the loop.
-  IGF.Builder.CreateBr(check);
-
-  // Fall through.
-  IGF.Builder.emitBlock(rest);
+static void emitPackExpansionWitnessTablePack(
+    IRGenFunction &IGF, Address pack, CanPackExpansionType expansionTy,
+    ProtocolConformanceRef conformance, llvm::Value *dynamicIndex,
+    llvm::Value *dynamicLength) {
+  emitPackExpansionPack(IGF, pack, expansionTy, dynamicIndex, dynamicLength,
+                        [&](auto *index) {
+                          llvm::Value *_metadata = nullptr;
+                          return emitPackExpansionElementWitnessTable(
+                              IGF, expansionTy, conformance,
+                              /*srcMetadataCache=*/&_metadata, index);
+                        });
 }
 
 StackAddress irgen::emitWitnessTablePack(IRGenFunction &IGF,
@@ -582,8 +561,9 @@ StackAddress irgen::emitWitnessTablePack(IRGenFunction &IGF,
 
     auto conformance = packConformance->getPatternConformances()[index];
     if (auto expansionTy = dyn_cast<PackExpansionType>(eltTy)) {
-      emitExpansionWitnessTablePack(IGF, pack.getAddress(), expansionTy,
-                                    conformance, dynamicIndex, dynamicLength);
+      emitPackExpansionWitnessTablePack(IGF, pack.getAddress(), expansionTy,
+                                        conformance, dynamicIndex,
+                                        dynamicLength);
     } else {
       Address eltPtr(
           IGF.Builder.CreateInBoundsGEP(pack.getAddress().getElementType(),