[compiler] Introduce code stubs for string relational comparisons.

src/compiler/code-stub-assembler.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_CODE_STUB_ASSEMBLER_H_
 #define V8_COMPILER_CODE_STUB_ASSEMBLER_H_
 
 #include <map>
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
@@ skipping 235 matching lines @@
 
   // Smi conversions.
   Node* SmiToFloat64(Node* value);
   Node* SmiToInt32(Node* value);
 
   // Smi operations.
   Node* SmiAdd(Node* a, Node* b);
   Node* SmiEqual(Node* a, Node* b);
   Node* SmiLessThan(Node* a, Node* b);
   Node* SmiLessThanOrEqual(Node* a, Node* b);
+  Node* SmiMin(Node* a, Node* b);
 
   // Load a value from the root array.
   Node* LoadRoot(Heap::RootListIndex root_index);
 
   // Check a value for smi-ness
   Node* WordIsSmi(Node* a);
 
   // Load an object pointer from a buffer that isn't in the heap.
   Node* LoadBufferObject(Node* buffer, int offset);
   // Load a field from an object on the heap.
@@ skipping 19 matching lines @@
   // Returns a node that is true if the given bit is set in |word32|.
   template <typename T>
   Node* BitFieldDecode(Node* word32) {
     return BitFieldDecode(word32, T::kShift, T::kMask);
   }
 
   Node* BitFieldDecode(Node* word32, uint32_t shift, uint32_t mask);
 
   // Branching helpers.
   // TODO(danno): Can we be more cleverish wrt. edge-split?
+  void BranchIfInt32LessThan(Node* a, Node* b, Label* if_true, Label* if_false);
   void BranchIfSmiLessThan(Node* a, Node* b, Label* if_true, Label* if_false);
   void BranchIfSmiLessThanOrEqual(Node* a, Node* b, Label* if_true,
                                   Label* if_false);
   void BranchIfFloat64Equal(Node* a, Node* b, Label* if_true, Label* if_false);
   void BranchIfFloat64LessThan(Node* a, Node* b, Label* if_true,
                                Label* if_false);
   void BranchIfFloat64LessThanOrEqual(Node* a, Node* b, Label* if_true,
                                       Label* if_false);
   void BranchIfFloat64GreaterThan(Node* a, Node* b, Label* if_true,
                                   Label* if_false);
@@ skipping 75 matching lines @@
   // Map of variables to the list of value nodes that have been added from each
   // merge path in their order of merging.
   std::map<Variable::Impl*, std::vector<Node*>> variable_merges_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CODE_STUB_ASSEMBLER_H_