Change the stack map search to require an exact match.

runtime/vm/code_descriptors_test.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 "platform/assert.h"
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64)
 
 #include "vm/ast.h"
 #include "vm/assembler.h"
@@ skipping 183 matching lines @@
 
   // Build and setup a stackmap for function 'A.foo' in order to test the
   // traversal of stack maps when a GC happens.
   StackmapBuilder* builder = new StackmapBuilder();
   EXPECT(builder != NULL);
   builder->SetSlotAsValue(0);  // var i.
   builder->SetSlotAsObject(1);  // var s1.
   builder->SetSlotAsValue(2);  // var k.
   builder->SetSlotAsObject(3);  // var s2.
   builder->SetSlotAsObject(4);  // var s3.
-  builder->AddEntry(0);  // Add a stack map entry at pc offset 0.
   const Code& code = Code::Handle(function_foo.unoptimized_code());
+  // Search for the pc of the call to 'func'.
+  const PcDescriptors& descriptors =
+      PcDescriptors::Handle(code.pc_descriptors());
+  for (int i = 0; i < descriptors.Length(); ++i) {
+    if (descriptors.DescriptorKind(i) == PcDescriptors::kFuncCall) {
+      builder->AddEntry(descriptors.PC(i) - code.EntryPoint());
+    }
+  }
   const Array& stack_maps = Array::Handle(builder->FinalizeStackmaps(code));
   code.set_stackmaps(stack_maps);
 
   // Now invoke 'A.moo' and it will trigger a GC when the native function
   // is called, this should then cause the stack map of function 'A.foo'
   // to be traversed and the appropriate objects visited.
   GrowableArray<const Object*> arguments;
   const Array& kNoArgumentNames = Array::Handle();
   Object& result = Object::Handle();
   result = DartEntry::InvokeStatic(function_foo, arguments, kNoArgumentNames);
   EXPECT(!result.IsError());
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32 || defined(TARGET_ARCH_X64)