[turbofan] Limit use of FrameStateBeforeAndAfter helper.

src/compiler/ast-graph-builder.h

Index: src/compiler/ast-graph-builder.h
diff --git a/src/compiler/ast-graph-builder.h b/src/compiler/ast-graph-builder.h
index de2773c79d574d92c950a0ca8a75295bfba25cf0..8346a51d01a4abe44b36ca891473f57ebc9472af 100644
--- a/src/compiler/ast-graph-builder.h
+++ b/src/compiler/ast-graph-builder.h
@@ -231,11 +231,18 @@ class AstGraphBuilder : public AstVisitor {
   // Helper to indicate a node exits the function body.
   void UpdateControlDependencyToLeaveFunction(Node* exit);
 
-  // Builds deoptimization for a given node.
+  // Prepare information for lazy deoptimization. This information is attached
+  // to the given node and the output value produced by the node is combined.
+  // Conceptually this frame state is "after" a given operation.
   void PrepareFrameState(Node* node, BailoutId ast_id,
                          OutputFrameStateCombine framestate_combine =
                              OutputFrameStateCombine::Ignore());
 
+  // Prepare information for eager deoptimization. This information is carried
+  // by dedicated {Checkpoint} nodes that are wired into the effect chain.
+  // Conceptually this frame state is "before" a given operation.
+  void PrepareEagerCheckpoint(BailoutId ast_id);
+
   BitVector* GetVariablesAssignedInLoop(IterationStatement* stmt);
 
   // Check if the given statement is an OSR entry.