Store FP instead of SP in the exit info when transitioning from Dart to C++.

runtime/vm/stub_code_mips.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/globals.h"
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 37 matching lines @@
   __ sw(ZR, Address(SP, 2 * kWordSize));  // Push 0 for the PC marker
   __ sw(RA, Address(SP, 1 * kWordSize));
   __ sw(FP, Address(SP, 0 * kWordSize));
   __ mov(FP, SP);
 
   COMPILE_ASSERT((kAbiPreservedCpuRegs & (1 << S6)) != 0);
   __ LoadIsolate(S6);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to Dart VM C++ code.
-  __ sw(SP, Address(S6, Isolate::top_exit_frame_info_offset()));
+  __ sw(FP, Address(S6, Isolate::top_exit_frame_info_offset()));
 
 #if defined(DEBUG)
   { Label ok;
     // Check that we are always entering from Dart code.
     __ lw(T0, Address(S6, Isolate::vm_tag_offset()));
     __ BranchEqual(T0, Immediate(VMTag::kDartTagId), &ok);
     __ Stop("Not coming from Dart code.");
     __ Bind(&ok);
   }
 #endif
@@ skipping 88 matching lines @@
   __ sw(ZR, Address(SP, 2 * kWordSize));  // Push 0 for the PC marker
   __ sw(RA, Address(SP, 1 * kWordSize));
   __ sw(FP, Address(SP, 0 * kWordSize));
   __ mov(FP, SP);
 
   COMPILE_ASSERT((kAbiPreservedCpuRegs & (1 << S6)) != 0);
   __ LoadIsolate(S6);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to native code.
-  __ sw(SP, Address(S6, Isolate::top_exit_frame_info_offset()));
+  __ sw(FP, Address(S6, Isolate::top_exit_frame_info_offset()));
 
 #if defined(DEBUG)
   { Label ok;
     // Check that we are always entering from Dart code.
     __ lw(T0, Address(S6, Isolate::vm_tag_offset()));
     __ BranchEqual(T0, Immediate(VMTag::kDartTagId), &ok);
     __ Stop("Not coming from Dart code.");
     __ Bind(&ok);
   }
 #endif
@@ skipping 77 matching lines @@
   __ sw(ZR, Address(SP, 2 * kWordSize));  // Push 0 for the PC marker
   __ sw(RA, Address(SP, 1 * kWordSize));
   __ sw(FP, Address(SP, 0 * kWordSize));
   __ mov(FP, SP);
 
   COMPILE_ASSERT((kAbiPreservedCpuRegs & (1 << S6)) != 0);
   __ LoadIsolate(S6);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to native code.
-  __ sw(SP, Address(S6, Isolate::top_exit_frame_info_offset()));
+  __ sw(FP, Address(S6, Isolate::top_exit_frame_info_offset()));
 
 #if defined(DEBUG)
   { Label ok;
     // Check that we are always entering from Dart code.
     __ lw(T0, Address(S6, Isolate::vm_tag_offset()));
     __ BranchEqual(T0, Immediate(VMTag::kDartTagId), &ok);
     __ Stop("Not coming from Dart code.");
     __ Bind(&ok);
   }
 #endif
@@ skipping 2052 matching lines @@
 // Result:
 //  T1: entry point.
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
   EmitMegamorphicLookup(assembler, T0, T1, T1);
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS