Add SILInstruction::getNextInstruction() and getPreviousInstruction()

Author: atrick

include/swift/SIL/SILInstruction.h

@@ -459,6 +459,14 @@ class SILInstruction : public llvm::ilist_node<SILInstruction> {
     locationStorage = loc.storage;
   }
 
+  /// Return the next instruction or nullptr if this is the last instruction in
+  /// its block.
+  SILInstruction *getPreviousInstruction();
+
+  /// Return the previous instruction or nullptr if this is the first
+  /// instruction in its block.
+  SILInstruction *getNextInstruction();
+
   /// This method unlinks 'self' from the containing basic block and deletes it.
   void eraseFromParent();
 
@@ -1013,6 +1021,14 @@ class SingleValueInstruction : public SILInstruction, public ValueBase {
   /// If this is an instruction which "defines" an opened archetype, it is
   /// returned.
   CanArchetypeType getOpenedArchetype() const;
+
+  SILInstruction *getPreviousInstruction() {
+    return SILInstruction::getPreviousInstruction();
+  }
+
+  SILInstruction *getNextInstruction() {
+    return SILInstruction::getNextInstruction();
+  }
 };
 
 struct SILNodeOffsetChecker {

lib/SIL/IR/SILInstruction.cpp

@@ -103,6 +103,16 @@ SILModule &SILInstruction::getModule() const {
   return getFunction()->getModule();
 }
 
+SILInstruction *SILInstruction::getPreviousInstruction() {
+  auto pos = getIterator();
+  return pos == getParent()->begin() ? nullptr : &*std::prev(pos);
+}
+
+SILInstruction *SILInstruction::getNextInstruction() {
+  auto nextPos = std::next(getIterator());
+  return nextPos == getParent()->end() ? nullptr : &*nextPos;
+}
+
 void SILInstruction::removeFromParent() {
 #ifndef NDEBUG
   for (auto result : getResults()) {

lib/SILOptimizer/Utils/ShrinkBorrowScope.cpp

@@ -20,23 +20,6 @@
 
 using namespace swift;
 
-//===----------------------------------------------------------------------===//
-//                           MARK: Local utilities
-//===----------------------------------------------------------------------===//
-
-// TODO: Move to be member function on SILInstruction.
-static SILInstruction *getPreviousInstruction(SILInstruction *inst) {
-  auto pos = inst->getIterator();
-  return pos == inst->getParent()->begin() ? nullptr
-                                           : &*std::prev(inst->getIterator());
-}
-
-// TODO: Move to be member function on SILInstruction.
-static SILInstruction *getNextInstruction(SILInstruction *inst) {
-  auto nextPos = std::next(inst->getIterator());
-  return nextPos == inst->getParent()->end() ? nullptr : &*nextPos;
-}
-
 //===----------------------------------------------------------------------===//
 //                       MARK: ShrinkBorrowScope
 //===----------------------------------------------------------------------===//
@@ -318,7 +301,7 @@ void ShrinkBorrowScope::findBarriers() {
       assert(tryHoistOverInstruction(block->getTerminator()));
     }
     SILInstruction *barrier = nullptr;
-    while ((instruction = getPreviousInstruction(instruction))) {
+    while ((instruction = instruction->getPreviousInstruction())) {
       if (instruction == introducer) {
         barrier = instruction;
         break;
@@ -354,7 +337,7 @@ bool ShrinkBorrowScope::rewrite() {
 
   // Insert the new end_borrow instructions that occur after deinit barriers.
   for (auto pair : barrierInstructions) {
-    auto *insertionPoint = getNextInstruction(pair.second);
+    auto *insertionPoint = pair.second->getNextInstruction();
     createdBorrow |= createEndBorrow(insertionPoint);
   }