Fix OSR for nested loops.

src/full-codegen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 304 matching lines @@
 #endif
   LOG_CODE_EVENT(isolate,
                  CodeStartLinePosInfoRecordEvent(masm.positions_recorder()));
 
   FullCodeGenerator cgen(&masm, info);
   cgen.Generate();
   if (cgen.HasStackOverflow()) {
     ASSERT(!isolate->has_pending_exception());
     return false;
   }
-  unsigned table_offset = cgen.EmitStackCheckTable();
+  unsigned table_offset = cgen.EmitBackEdgeTable();
 
   Code::Flags flags = Code::ComputeFlags(Code::FUNCTION);
   Handle<Code> code = CodeGenerator::MakeCodeEpilogue(&masm, flags, info);
   code->set_optimizable(info->IsOptimizable() &&
                         !info->function()->flags()->Contains(kDontOptimize) &&
                         info->function()->scope()->AllowsLazyCompilation());
   cgen.PopulateDeoptimizationData(code);
   cgen.PopulateTypeFeedbackInfo(code);
   cgen.PopulateTypeFeedbackCells(code);
   code->set_has_deoptimization_support(info->HasDeoptimizationSupport());
   code->set_handler_table(*cgen.handler_table());
 #ifdef ENABLE_DEBUGGER_SUPPORT
   code->set_has_debug_break_slots(
       info->isolate()->debugger()->IsDebuggerActive());
   code->set_compiled_optimizable(info->IsOptimizable());
 #endif  // ENABLE_DEBUGGER_SUPPORT
   code->set_allow_osr_at_loop_nesting_level(0);
   code->set_profiler_ticks(0);
-  code->set_stack_check_table_offset(table_offset);
-  code->set_stack_check_patched_for_osr(false);
+  code->set_back_edge_table_offset(table_offset);
+  code->set_back_edges_patched_for_osr(false);
   CodeGenerator::PrintCode(code, info);
   info->SetCode(code);  // May be an empty handle.
 #ifdef ENABLE_GDB_JIT_INTERFACE
   if (FLAG_gdbjit && !code.is_null()) {
     GDBJITLineInfo* lineinfo =
         masm.positions_recorder()->DetachGDBJITLineInfo();
 
     GDBJIT(RegisterDetailedLineInfo(*code, lineinfo));
   }
 #endif
   if (!code.is_null()) {
     void* line_info =
         masm.positions_recorder()->DetachJITHandlerData();
     LOG_CODE_EVENT(isolate, CodeEndLinePosInfoRecordEvent(*code, line_info));
   }
   return !code.is_null();
 }
 
 
-unsigned FullCodeGenerator::EmitStackCheckTable() {
-  // The stack check table consists of a length (in number of entries)
+unsigned FullCodeGenerator::EmitBackEdgeTable() {
+  // The back edge table consists of a length (in number of entries)
   // field, and then a sequence of entries.  Each entry is a pair of AST id
   // and code-relative pc offset.
   masm()->Align(kIntSize);
   unsigned offset = masm()->pc_offset();
-  unsigned length = stack_checks_.length();
+  unsigned length = back_edges_.length();
   __ dd(length);
   for (unsigned i = 0; i < length; ++i) {
-    __ dd(stack_checks_[i].id.ToInt());
-    __ dd(stack_checks_[i].pc_and_state);
+    __ dd(back_edges_[i].id.ToInt());
+    __ dd(back_edges_[i].pc);
+    __ db(back_edges_[i].loop_depth);
   }
   return offset;
 }
 
 
 void FullCodeGenerator::PopulateDeoptimizationData(Handle<Code> code) {
   // Fill in the deoptimization information.
   ASSERT(info_->HasDeoptimizationSupport() || bailout_entries_.is_empty());
   if (!info_->HasDeoptimizationSupport()) return;
   int length = bailout_entries_.length();
@@ skipping 85 matching lines @@
 void FullCodeGenerator::RecordTypeFeedbackCell(
     TypeFeedbackId id, Handle<JSGlobalPropertyCell> cell) {
   TypeFeedbackCellEntry entry = { id, cell };
   type_feedback_cells_.Add(entry, zone());
 }
 
 
 void FullCodeGenerator::RecordBackEdge(BailoutId ast_id) {
   // The pc offset does not need to be encoded and packed together with a state.
   ASSERT(masm_->pc_offset() > 0);
-  BailoutEntry entry = { ast_id, static_cast<unsigned>(masm_->pc_offset()) };
-  stack_checks_.Add(entry, zone());
+  ASSERT(loop_depth() > 0);
+  uint8_t depth = Min(loop_depth(), Code::kMaxLoopNestingMarker);
+  BackEdgeEntry entry =
+      { ast_id, static_cast<unsigned>(masm_->pc_offset()), depth };
+  back_edges_.Add(entry, zone());
 }
 
 
 bool FullCodeGenerator::ShouldInlineSmiCase(Token::Value op) {
   // Inline smi case inside loops, but not division and modulo which
   // are too complicated and take up too much space.
   if (op == Token::DIV ||op == Token::MOD) return false;
   if (FLAG_always_inline_smi_code) return true;
   return loop_depth_ > 0;
 }
@@ skipping 751 matching lines @@
   // Pop context.
   LoadContextField(context_register(), Context::PREVIOUS_INDEX);
   // Update local stack frame context field.
   StoreToFrameField(StandardFrameConstants::kContextOffset, context_register());
 }
 
 
 void FullCodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
   Comment cmnt(masm_, "[ DoWhileStatement");
   SetStatementPosition(stmt);
-  Label body, stack_check;
+  Label body, book_keeping;
 
   Iteration loop_statement(this, stmt);
   increment_loop_depth();
 
   __ bind(&body);
   Visit(stmt->body());
 
   // Record the position of the do while condition and make sure it is
   // possible to break on the condition.
   __ bind(loop_statement.continue_label());
   PrepareForBailoutForId(stmt->ContinueId(), NO_REGISTERS);
   SetExpressionPosition(stmt->cond(), stmt->condition_position());
   VisitForControl(stmt->cond(),
-                  &stack_check,
+                  &book_keeping,
                   loop_statement.break_label(),
-                  &stack_check);
+                  &book_keeping);
 
   // Check stack before looping.
   PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  __ bind(&stack_check);
+  __ bind(&book_keeping);
   EmitBackEdgeBookkeeping(stmt, &body);
   __ jmp(&body);
 
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
   __ bind(loop_statement.break_label());
   decrement_loop_depth();
 }
 
 
 void FullCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
@@ skipping 319 matching lines @@
   }
 
   return false;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal