Added stack overflow checks at backward branches in order to allow interrupting endless loops. Bett…

runtime/vm/code_generator_x64.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/code_generator.h"
 
 #include "lib/error.h"
@@ skipping 1779 matching lines @@
 
   // Call operator.
   GenerateBinaryOperatorCall(node->id(), node->token_index(), node->Name());
   // Result is in RAX.
   if (IsResultNeeded(node)) {
     __ pushq(RAX);
   }
 }
 
 
+void CodeGenerator::HandleBackwardBranch(
+    intptr_t loop_id, intptr_t token_index) {
+  // Use stack overflow check to eventually stop execution of loops.
+  // This is necessary only if a loop does not have calls.
+  __ movq(TMP, Immediate(Isolate::Current()->stack_limit_address()));
+  __ cmpq(RSP, Address(TMP, 0));
+  Label no_stack_overflow;
+  __ j(ABOVE, &no_stack_overflow);
+  GenerateCallRuntime(loop_id,
+                      token_index,
+                      kStackOverflowRuntimeEntry);
+  __ Bind(&no_stack_overflow);
+}
+
+
 void CodeGenerator::VisitWhileNode(WhileNode* node) {
   const Bool& bool_true = Bool::ZoneHandle(Bool::True());
   SourceLabel* label = node->label();
   __ Bind(label->continue_label());
   node->condition()->Visit(this);
   GenerateConditionTypeCheck(node->id(), node->condition()->token_index());
   __ popq(RAX);
   __ LoadObject(RDX, bool_true);
   __ cmpq(RAX, RDX);
   __ j(NOT_EQUAL, label->break_label());
   node->body()->Visit(this);
+  HandleBackwardBranch(node->id(), node->token_index());
   __ jmp(label->continue_label());
   __ Bind(label->break_label());
 }
 
 
 void CodeGenerator::VisitDoWhileNode(DoWhileNode* node) {
   const Bool& bool_true = Bool::ZoneHandle(Bool::True());
   SourceLabel* label = node->label();
   Label loop;
   __ Bind(&loop);
   node->body()->Visit(this);
+  HandleBackwardBranch(node->id(), node->token_index());
   __ Bind(label->continue_label());
   node->condition()->Visit(this);
   GenerateConditionTypeCheck(node->id(), node->condition()->token_index());
   __ popq(RAX);
   __ LoadObject(RDX, bool_true);
   __ cmpq(RAX, RDX);
   __ j(EQUAL, &loop);
   __ Bind(label->break_label());
 }
 
 
 void CodeGenerator::VisitForNode(ForNode* node) {
   const Bool& bool_true = Bool::ZoneHandle(Bool::True());
   node->initializer()->Visit(this);
   SourceLabel* label = node->label();
   Label loop;
   __ Bind(&loop);
   if (node->condition() != NULL) {
     node->condition()->Visit(this);
     GenerateConditionTypeCheck(node->id(), node->condition()->token_index());
     __ popq(RAX);
     __ LoadObject(RDX, bool_true);
     __ cmpq(RAX, RDX);
     __ j(NOT_EQUAL, label->break_label());
   }
   node->body()->Visit(this);
+  HandleBackwardBranch(node->id(), node->token_index());
   __ Bind(label->continue_label());
   node->increment()->Visit(this);
   __ jmp(&loop);
   __ Bind(label->break_label());
 }
 
 
 void CodeGenerator::VisitJumpNode(JumpNode* node) {
   SourceLabel* label = node->label();
 
@@ skipping 831 matching lines @@
   const Error& error = Error::Handle(
       Parser::FormatError(script, token_index, "Error", format, args));
   va_end(args);
   Isolate::Current()->long_jump_base()->Jump(1, error);
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64