Fix an off-by-one error in the stack frame iteration.

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 45 matching lines @@
   if (setjmp(*jump.Set()) == 0) {
     // Build some stack map entries.
     StackmapBuilder* builder = new StackmapBuilder();
     EXPECT(builder != NULL);
     builder->SetSlotAsObject(0);
     EXPECT(builder->IsSlotObject(0));
     builder->AddEntry(0);  // Add a stack map entry at pc offset 0.
     builder->SetSlotAsValue(1);
     EXPECT(!builder->IsSlotObject(1));
     builder->SetSlotAsObject(2);
+    EXPECT(builder->IsSlotObject(2));
     builder->AddEntry(1);  // Add a stack map entry at pc offset 1.
-    EXPECT(builder->IsSlotObject(2));
     builder->SetSlotRangeAsObject(3, 5);
     for (intptr_t i = 3; i <= 5; i++) {
       EXPECT(builder->IsSlotObject(i));
     }
     builder->AddEntry(2);  // Add a stack map entry at pc offset 2.
     builder->SetSlotRangeAsValue(6, 9);
     for (intptr_t i = 6; i <= 9; i++) {
       EXPECT(!builder->IsSlotObject(i));
     }
     builder->SetSlotAsObject(10);
+    EXPECT(builder->IsSlotObject(10));
     builder->AddEntry(3);  // Add a stack map entry at pc offset 3.
 
     const Error& error =
         Error::Handle(Compiler::CompileParsedFunction(parsed_function));
     EXPECT(error.IsNull());
     const Code& code = Code::Handle(function.CurrentCode());
 
     const Array& stack_maps = Array::Handle(builder->FinalizeStackmaps(code));
     code.set_stackmaps(stack_maps);
     const Array& stack_map_list = Array::Handle(code.stackmaps());
     EXPECT(!stack_map_list.IsNull());
     Stackmap& stack_map = Stackmap::Handle();
     EXPECT_EQ(4, stack_map_list.Length());
 
     // Validate the first stack map entry.
     stack_map ^= stack_map_list.At(0);
     EXPECT(stack_map.IsObject(0));
-    EXPECT_EQ(0, stack_map.MinimumBitOffset());
-    EXPECT_EQ(0, stack_map.MaximumBitOffset());
+    EXPECT_EQ(0, stack_map.MinimumBitIndex());
+    EXPECT_EQ(0, stack_map.MaximumBitIndex());
 
     // Validate the second stack map entry.
     stack_map ^= stack_map_list.At(1);
     EXPECT(stack_map.IsObject(0));
     EXPECT(!stack_map.IsObject(1));
     EXPECT(stack_map.IsObject(2));
-    EXPECT_EQ(0, stack_map.MinimumBitOffset());
-    EXPECT_EQ(2, stack_map.MaximumBitOffset());
+    EXPECT_EQ(0, stack_map.MinimumBitIndex());
+    EXPECT_EQ(2, stack_map.MaximumBitIndex());
 
     // Validate the third stack map entry.
     stack_map ^= stack_map_list.At(2);
     EXPECT(stack_map.IsObject(0));
     EXPECT(!stack_map.IsObject(1));
     for (intptr_t i = 2; i <= 5; i++) {
       EXPECT(stack_map.IsObject(i));
     }
-    EXPECT_EQ(0, stack_map.MinimumBitOffset());
-    EXPECT_EQ(5, stack_map.MaximumBitOffset());
+    EXPECT_EQ(0, stack_map.MinimumBitIndex());
+    EXPECT_EQ(5, stack_map.MaximumBitIndex());
 
     // Validate the fourth stack map entry.
     stack_map ^= stack_map_list.At(3);
     EXPECT(stack_map.IsObject(0));
     EXPECT(!stack_map.IsObject(1));
     for (intptr_t i = 2; i <= 5; i++) {
       EXPECT(stack_map.IsObject(i));
     }
     for (intptr_t i = 6; i <= 9; i++) {
       EXPECT(!stack_map.IsObject(i));
     }
     EXPECT(stack_map.IsObject(10));
-    EXPECT_EQ(0, stack_map.MinimumBitOffset());
-    EXPECT_EQ(10, stack_map.MaximumBitOffset());
+    EXPECT_EQ(0, stack_map.MinimumBitIndex());
+    EXPECT_EQ(10, stack_map.MaximumBitIndex());
     retval = true;
   } else {
     retval = false;
   }
   EXPECT(retval);
   isolate->set_long_jump_base(base);
 }
 CODEGEN_TEST_RUN(StackmapCodegen, Smi::New(1))
 
 
@@ skipping 46 matching lines @@
       Function::Handle(cls.LookupStaticFunction(function_moo_name));
   EXPECT(CompilerTest::TestCompileFunction(function_moo));
   EXPECT(function_moo.HasCode());
 
   String& function_foo_name = String::Handle(String::New("foo"));
   Function& function_foo =
       Function::Handle(cls.LookupStaticFunction(function_foo_name));
   EXPECT(CompilerTest::TestCompileFunction(function_foo));
   EXPECT(function_foo.HasCode());
 
-  // Build and setup a stackmap for function 'A.foo' in order to test the
-  // traversal of stack maps when a GC happens.
+  // Build and setup a stackmap for the call to 'func' in '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->SetSlotAsObject(5);  // First argument to func(i, k).
+  builder->SetSlotAsObject(6);  // Second argument to func(i, k).
   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());
+  int call_count = 0;
   for (int i = 0; i < descriptors.Length(); ++i) {
     if (descriptors.DescriptorKind(i) == PcDescriptors::kFuncCall) {
       builder->AddEntry(descriptors.PC(i) - code.EntryPoint());
+      ++call_count;
     }
   }
+  // We can't easily check that we put the stackmap at the correct pc, but
+  // we did if there was exactly one call seen.
+  EXPECT(call_count == 1);
   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)