VM(RegExp): Allow OSR optimization of RegExp :matcher functions.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
diff --git a/runtime/vm/intermediate_language.h b/runtime/vm/intermediate_language.h
index 588d082bc70a03551fc685729f18f6c3db2a823a..a00be28e4f53a3468bf8838ed7cc517cca17cc4a 100644
--- a/runtime/vm/intermediate_language.h
+++ b/runtime/vm/intermediate_language.h
@@ -7266,12 +7266,26 @@ class UnaryDoubleOpInstr : public TemplateDefinition<1, NoThrow, Pure> {
 
 class CheckStackOverflowInstr : public TemplateInstruction<0, NoThrow> {
  public:
+  enum Kind {
+    // Full stack overflow checks are emitted in both unoptimized and
+    // optimized versions of the code.
+    kFull,
+
+    // OsrEntry stack overflow checks are only needed in the unoptimized code
+    // because we can't OSR optimized code.
+    kOsrEntry,
+  };
+
   CheckStackOverflowInstr(TokenPosition token_pos,
                           intptr_t loop_depth,
-                          intptr_t deopt_id)
+                          intptr_t deopt_id,
+                          Kind kind = kFull)
       : TemplateInstruction(deopt_id),
         token_pos_(token_pos),
-        loop_depth_(loop_depth) {}
+        loop_depth_(loop_depth),
+        kind_(kind) {
+    ASSERT(kind != kOsrEntry || loop_depth > 0);
+  }
 
   virtual TokenPosition token_pos() const { return token_pos_; }
   bool in_loop() const { return loop_depth_ > 0; }
@@ -7281,6 +7295,8 @@ class CheckStackOverflowInstr : public TemplateInstruction<0, NoThrow> {
 
   virtual bool ComputeCanDeoptimize() const { return true; }
 
+  virtual Instruction* Canonicalize(FlowGraph* flow_graph);
+
   virtual EffectSet Effects() const { return EffectSet::None(); }
 
   PRINT_OPERANDS_TO_SUPPORT
@@ -7288,6 +7304,7 @@ class CheckStackOverflowInstr : public TemplateInstruction<0, NoThrow> {
  private:
   const TokenPosition token_pos_;
   const intptr_t loop_depth_;
+  const Kind kind_;
 
   DISALLOW_COPY_AND_ASSIGN(CheckStackOverflowInstr);
 };