SwiftCompilerSources: add more APIs to create new basic blocks

* rename `Context.splitBlock(at:)` -> `Context.splitBlock(before:)`
* add `Context.splitBlock(after:)`
* add `Context.createBlock(after:)`

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjCBridgingOptimization.swift

@@ -185,9 +185,9 @@ private func optimizeNonOptionalBridging(_ apply: ApplyInst,
   // empty value.
   // Create the needed blocks of the `switch_enum` CFG diamond.
   let origBlock = bridgeToSwiftCall.parentBlock
-  let someBlock = context.splitBlock(at: bridgeToSwiftCall)
-  let noneBlock = context.splitBlock(at: bridgeToSwiftCall)
-  let continueBlock = context.splitBlock(at: bridgeToSwiftCall)
+  let someBlock = context.splitBlock(before: bridgeToSwiftCall)
+  let noneBlock = context.splitBlock(before: bridgeToSwiftCall)
+  let continueBlock = context.splitBlock(before: bridgeToSwiftCall)
 
 
   let builder = Builder(atEndOf: origBlock, location: bridgeToSwiftCall.location, context)

SwiftCompilerSources/Sources/Optimizer/PassManager/Context.swift

@@ -55,9 +55,24 @@ extension MutatingContext {
   ///
   /// `inst` and all subsequent instructions are moved to the new block, while all
   /// instructions _before_ `inst` remain in the original block.
-  func splitBlock(at inst: Instruction) -> BasicBlock {
+  func splitBlock(before inst: Instruction) -> BasicBlock {
     notifyBranchesChanged()
-    return _bridged.splitBlock(inst.bridged).block
+    return _bridged.splitBlockBefore(inst.bridged).block
+  }
+
+  /// Splits the basic block, which contains `inst`, after `inst` and returns the
+  /// new block.
+  ///
+  /// All subsequent instructions after `inst` are moved to the new block, while `inst` and all
+  /// instructions _before_ `inst` remain in the original block.
+  func splitBlock(after inst: Instruction) -> BasicBlock {
+    notifyBranchesChanged()
+    return _bridged.splitBlockAfter(inst.bridged).block
+  }
+
+  func createBlock(after block: BasicBlock) -> BasicBlock {
+    notifyBranchesChanged()
+    return _bridged.createBlockAfter(block.bridged).block
   }
 
   func erase(instruction: Instruction) {

SwiftCompilerSources/Sources/Optimizer/TestPasses/TestInstructionIteration.swift

@@ -61,7 +61,7 @@ private func handle(instruction: Instruction, _ context: FunctionPassContext) {
       case "delete_branches":
         deleteAllInstructions(ofType: BranchInst.self, in: instruction.parentBlock, context)
       case "split_block":
-        _ = context.splitBlock(at: instruction)
+        _ = context.splitBlock(before: instruction)
       default:
         break
     }

include/swift/SILOptimizer/OptimizerBridging.h

@@ -190,7 +190,9 @@ struct BridgedPassContext {
     bool cfgChanged;
   };
 
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitBlock(BridgedInstruction bridgedInst) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitBlockBefore(BridgedInstruction bridgedInst) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitBlockAfter(BridgedInstruction bridgedInst) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock createBlockAfter(BridgedBasicBlock bridgedBlock) const;
   BRIDGED_INLINE void eraseInstruction(BridgedInstruction inst) const;
   BRIDGED_INLINE void eraseBlock(BridgedBasicBlock block) const;
   bool tryOptimizeApplyOfPartialApply(BridgedInstruction closure) const;

include/swift/SILOptimizer/OptimizerBridgingImpl.h

@@ -183,11 +183,21 @@ BridgedDiagnosticEngine BridgedPassContext::getDiagnosticEngine() const {
 
 // SIL modifications
 
-BridgedBasicBlock BridgedPassContext::splitBlock(BridgedInstruction bridgedInst) const {
+BridgedBasicBlock BridgedPassContext::splitBlockBefore(BridgedInstruction bridgedInst) const {
   auto *block = bridgedInst.unbridged()->getParent();
   return {block->split(bridgedInst.unbridged()->getIterator())};
 }
 
+BridgedBasicBlock BridgedPassContext::splitBlockAfter(BridgedInstruction bridgedInst) const {
+  auto *block = bridgedInst.unbridged()->getParent();
+  return {block->split(std::next(bridgedInst.unbridged()->getIterator()))};
+}
+
+BridgedBasicBlock BridgedPassContext::createBlockAfter(BridgedBasicBlock bridgedBlock) const {
+  swift::SILBasicBlock *block = bridgedBlock.unbridged();
+  return {block->getParent()->createBasicBlockAfter(block)};
+}
+
 void BridgedPassContext::eraseInstruction(BridgedInstruction inst) const {
   invocation->eraseInstruction(inst.unbridged());
 }