DBC: Eager deoptimization and CheckSmi instruction.

runtime/vm/deopt_instructions.cc

 // Copyright (c) 2013, 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/deopt_instructions.h"
 
 #include "vm/assembler.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
 #include "vm/intermediate_language.h"
@@ skipping 49 matching lines @@
   // Do not include incoming arguments if there are optional arguments
   // (they are copied into local space at method entry).
   num_args_ =
       function.HasOptionalParameters() ? 0 : function.num_fixed_parameters();
 
   // The fixed size section of the (fake) Dart frame called via a stub by the
   // optimized function contains FP, PP (ARM and MIPS only), PC-marker and
   // return-address. This section is copied as well, so that its contained
   // values can be updated before returning to the deoptimized function.
   // Note: on DBC stack grows upwards unlike on all other architectures.
+  const intptr_t frame_size =
+#if defined(TARGET_ARCH_DBC)
+      (static_cast<intptr_t>(frame->sp()) -
+       static_cast<intptr_t>(frame->fp())) / kWordSize;
+#else
+      (static_cast<intptr_t>(frame->fp()) -
+       static_cast<intptr_t>(frame->sp())) / kWordSize;
+#endif
   source_frame_size_ =
       + kDartFrameFixedSize  // For saved values below sp.
-#if !defined(TARGET_ARCH_DBC)
-      + ((frame->fp() - frame->sp()) / kWordSize)  // For frame size incl. sp.
-#else
-      + ((frame->sp() - frame->fp()) / kWordSize)  // For frame size incl. sp.

[zra, 2016/06/07 22:31:28]

For some reason sp() is < fp() ? Moved around to at least avoid getting
something totally wrong from unsigned arithmetic cast to signed.

[Vyacheslav Egorov (Google), 2016/06/08 11:58:53]

If SP is less then FP on DBC then this is bug somewhere else.

[zra, 2016/06/08 17:46:30]

Added ASSERT.

-#endif  // !defined(TARGET_ARCH_DBC)
+      + frame_size  // For frame size incl. sp.
       + 1  // For fp.
       + kParamEndSlotFromFp  // For saved values above fp.
       + num_args_;  // For arguments.
 
   source_frame_ = FrameBase(frame);
 
   if (dest_options == kDestIsOriginalFrame) {
     // Work from a copy of the source frame.
     intptr_t* original_frame = source_frame_;
     source_frame_ = new intptr_t[source_frame_size_];
@@ skipping 1251 matching lines @@
                           Smi* offset,
                           TypedData* info,
                           Smi* reason) {
   intptr_t i = index * kEntrySize;
   *offset ^= table.At(i);
   *info ^= table.At(i + 1);
   *reason ^= table.At(i + 2);
 }
 
 }  // namespace dart