X64: Implement DoComputeOsrOutputFrame and fix Generate_OnStackReplacement....

src/x64/full-codegen-x64.cc

 // Copyright 2011 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 249 matching lines @@
   NearLabel ok;
   __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
   __ j(above_equal, &ok);
   StackCheckStub stub;
   __ CallStub(&stub);
   // Record a mapping of this PC offset to the OSR id.  This is used to find
   // the AST id from the unoptimized code in order to use it as a key into
   // the deoptimization input data found in the optimized code.
   RecordStackCheck(stmt->OsrEntryId());
 
+  // Loop stack checks can be patched to perform on-stack replacement. In
+  // order to decide whether or not to perform OSR we embed the loop depth
+  // in a test instruction after the call so we can extract it from the OSR
+  // builtin.
+  ASSERT(loop_depth() > 0);
+  __ testl(rax, Immediate(Min(loop_depth(), Code::kMaxLoopNestingMarker)));
+
   __ bind(&ok);
   PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
   // Record a mapping of the OSR id to this PC.  This is used if the OSR
   // entry becomes the target of a bailout.  We don't expect it to be, but
   // we want it to work if it is.
   PrepareForBailoutForId(stmt->OsrEntryId(), NO_REGISTERS);
 }
 
 
 void FullCodeGenerator::EmitReturnSequence() {
@@ skipping 3488 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64