Setup R10/EDX to be valid Oops before stub calls

runtime/vm/flow_graph_compiler_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"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1230 matching lines @@
 
 
 void FlowGraphCompiler::EmitInstanceCall(ExternalLabel* target_label,
                                          const ICData& ic_data,
                                          intptr_t argument_count,
                                          intptr_t deopt_id,
                                          intptr_t token_pos,
                                          LocationSummary* locs) {
   ASSERT(Array::Handle(ic_data.arguments_descriptor()).Length() > 0);
   __ TraceSimMsg("InstanceCall");
+  __ LoadImmediate(S4, 0);
   __ LoadObject(S5, ic_data);
   GenerateDartCall(deopt_id,
                    token_pos,
                    target_label,
                    PcDescriptors::kIcCall,
                    locs);
   __ TraceSimMsg("InstanceCall return");
   __ Drop(argument_count);
+#if defined(DEBUG)
+  __ LoadImmediate(S4, 1);  // Garbage that looks like an object.
+#endif
 }
 
 
 void FlowGraphCompiler::EmitMegamorphicInstanceCall(
     const ICData& ic_data,
     intptr_t argument_count,
     intptr_t deopt_id,
     intptr_t token_pos,
     LocationSummary* locs) {
   MegamorphicCacheTable* table = Isolate::Current()->megamorphic_cache_table();
@@ skipping 61 matching lines @@
     const ICData& ic_data) {
   uword label_address = 0;
   if (ic_data.NumArgsTested() == 0) {
     label_address = StubCode::ZeroArgsUnoptimizedStaticCallEntryPoint();
   } else if (ic_data.NumArgsTested() == 2) {
     label_address = StubCode::TwoArgsUnoptimizedStaticCallEntryPoint();
   } else {
     UNIMPLEMENTED();
   }
   ExternalLabel target_label(label_address);
+  __ LoadImmediate(S4, 0);
   __ LoadObject(S5, ic_data);
   GenerateDartCall(deopt_id,
                    token_pos,
                    &target_label,
                    PcDescriptors::kUnoptStaticCall,
                    locs);
+#if defined(DEBUG)
+  __ LoadImmediate(S4, 0);  // Garbage that looks like an object.

[Ivan Posva, 2014/06/12 22:55:09]

1

Maybe you should define a constant for this?

[rmacnak, 2014/06/12 23:50:15]

Changed to kInvalidObjectPointer.

+#endif
   __ Drop(argument_count);
 }
 
 
 void FlowGraphCompiler::EmitOptimizedStaticCall(
     const Function& function,
     const Array& arguments_descriptor,
     intptr_t argument_count,
     intptr_t deopt_id,
     intptr_t token_pos,
@@ skipping 51 matching lines @@
   __ TraceSimMsg("EqualityRegRegCompare");
   __ Comment("EqualityRegRegCompare");
   if (needs_number_check) {
     __ addiu(SP, SP, Immediate(-2 * kWordSize));
     __ sw(left, Address(SP, 1 * kWordSize));
     __ sw(right, Address(SP, 0 * kWordSize));
     if (is_optimizing()) {
       __ BranchLinkPatchable(
           &StubCode::OptimizedIdenticalWithNumberCheckLabel());
     } else {
+      __ LoadImmediate(S4, 0);
+      __ LoadImmediate(S5, 0);
       __ BranchLinkPatchable(
           &StubCode::UnoptimizedIdenticalWithNumberCheckLabel());
     }
     if (token_pos != Scanner::kNoSourcePos) {
       AddCurrentDescriptor(PcDescriptors::kRuntimeCall,
                            Isolate::kNoDeoptId,
                            token_pos);
     }
+#if defined(DEBUG)
+    if (!is_optimizing()) {
+      // Do this *after* adding the pc descriptor!
+      __ LoadImmediate(S4, 1);  // Garbage that looks like an object.
+      __ LoadImmediate(S5, 1);
+    }
+#endif
     __ TraceSimMsg("EqualityRegRegCompare return");
     // Stub returns result in CMPRES1. If it is 0, then left and right are
     // equal.
     __ lw(right, Address(SP, 0 * kWordSize));
     __ lw(left, Address(SP, 1 * kWordSize));
     __ addiu(SP, SP, Immediate(2 * kWordSize));
   } else {
     __ slt(CMPRES1, left, right);
     __ slt(CMPRES2, right, left);
   }
@@ skipping 355 matching lines @@
   __ AddImmediate(SP, kDoubleSize);
 }
 
 
 #undef __
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS