Collect type information based on stack allocated values for OSR.

src/typing.cc

Index: src/typing.cc
diff --git a/src/typing.cc b/src/typing.cc
index 9458d6dc2fe401142f7b4e3392cea419fe94500c..cec5f863de11be36cc5c523a728db3ff47fced4c 100644
--- a/src/typing.cc
+++ b/src/typing.cc
@@ -27,6 +27,8 @@
 
 #include "typing.h"
 
+#include "frames.h"
+#include "frames-inl.h"
 #include "parser.h"  // for CompileTimeValue; TODO(rossberg): should move
 #include "scopes.h"
 
@@ -68,6 +70,75 @@ void AstTyper::Run(CompilationInfo* info) {
 
 #undef RECURSE
 
+
+Effect AstTyper::ObservedOnStack(Object* value) {
+  Type* lower = Type::OfCurrently(Handle<Object>(value, isolate()));
+  return Effect(Bounds(lower, Type::Any(), isolate()));
+}
+
+
+#ifdef OBJECT_PRINT
+  static void PrintObserved(Variable* var, Object* value, Handle<Type> type) {
+    PrintF("  observed %s ", var->IsParameter() ? "param" : "local");
+    var->name()->Print();
+    PrintF(" : ");
+    value->ShortPrint();
+    PrintF(" -> ");
+    type->TypePrint();
+  }
+#endif  // OBJECT_PRINT
+
+
+void AstTyper::ObserveTypesAtOsrEntry(IterationStatement* stmt) {
+  if (stmt->OsrEntryId() != info_->osr_ast_id()) return;
+
+  DisallowHeapAllocation no_gc;
+  JavaScriptFrameIterator it(isolate());
+  JavaScriptFrame* frame = it.frame();
+  Scope* scope = info_->scope();
+
+  // Assert that the frame on the stack belongs to the function we want to OSR.
+  ASSERT_EQ(*info_->closure(), frame->function());
+
+  int params = scope->num_parameters();
+  int locals = scope->StackLocalCount();
+
+  // Use sequential composition to achieve desired narrowing.
+  // The receiver is a parameter with index -1.
+  store_.Seq(parameter_index(-1), ObservedOnStack(frame->receiver()));
+  for (int i = 0; i < params; i++) {
+    store_.Seq(parameter_index(i), ObservedOnStack(frame->GetParameter(i)));
+  }
+
+  for (int i = 0; i < locals; i++) {
+    store_.Seq(stack_local_index(i), ObservedOnStack(frame->GetExpression(i)));
+  }
+
+#ifdef OBJECT_PRINT
+  if (FLAG_trace_osr && FLAG_print_scopes) {
+    PrintObserved(scope->receiver(),
+                  frame->receiver(),
+                  store_.LookupBounds(parameter_index(-1)).lower);
+
+    for (int i = 0; i < params; i++) {
+      PrintObserved(scope->parameter(i),
+                    frame->GetParameter(i),
+                    store_.LookupBounds(parameter_index(i)).lower);
+    }
+
+    ZoneList<Variable*> local_vars(locals, zone());
+    ZoneList<Variable*> context_vars(scope->ContextLocalCount(), zone());
+    scope->CollectStackAndContextLocals(&local_vars, &context_vars);
+    for (int i = 0; i < locals; i++) {
+      PrintObserved(local_vars.at(i),
+                    frame->GetExpression(i),
+                    store_.LookupBounds(stack_local_index(i)).lower);
+    }
+  }
+#endif  // OBJECT_PRINT
+}
+
+
 #define RECURSE(call)                \
   do {                               \
     ASSERT(!HasStackOverflow());     \
@@ -221,6 +292,7 @@ void AstTyper::VisitDoWhileStatement(DoWhileStatement* stmt) {
   // computing the set of variables assigned in only some of the origins of the
   // control transfer (such as the loop body here).
   store_.Forget();  // Control may transfer here via looping or 'continue'.
+  ObserveTypesAtOsrEntry(stmt);
   RECURSE(Visit(stmt->body()));
   RECURSE(Visit(stmt->cond()));
   store_.Forget();  // Control may transfer here via 'break'.
@@ -235,6 +307,7 @@ void AstTyper::VisitWhileStatement(WhileStatement* stmt) {
 
   store_.Forget();  // Control may transfer here via looping or 'continue'.
   RECURSE(Visit(stmt->cond()));
+  ObserveTypesAtOsrEntry(stmt);
   RECURSE(Visit(stmt->body()));
   store_.Forget();  // Control may transfer here via termination or 'break'.
 }
@@ -251,6 +324,7 @@ void AstTyper::VisitForStatement(ForStatement* stmt) {
 
     RECURSE(Visit(stmt->cond()));
   }
+  ObserveTypesAtOsrEntry(stmt);
   RECURSE(Visit(stmt->body()));
   if (stmt->next() != NULL) {
     store_.Forget();  // Control may transfer here via 'continue'.
@@ -267,6 +341,7 @@ void AstTyper::VisitForInStatement(ForInStatement* stmt) {
 
   RECURSE(Visit(stmt->enumerable()));
   store_.Forget();  // Control may transfer here via looping or 'continue'.
+  ObserveTypesAtOsrEntry(stmt);
   RECURSE(Visit(stmt->body()));
   store_.Forget();  // Control may transfer here via 'break'.
 }