Remove isolate pointer from context objects.

runtime/vm/stub_code_ia32.cc

Index: runtime/vm/stub_code_ia32.cc
===================================================================
--- runtime/vm/stub_code_ia32.cc	(revision 41244)
+++ runtime/vm/stub_code_ia32.cc	(working copy)
@@ -47,8 +47,7 @@
 
   __ EnterFrame(0);
 
-  // Load current Isolate pointer from Context structure into EAX.
-  __ movl(EAX, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadIsolate(EAX);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to Dart VM C++ code.
@@ -168,8 +167,7 @@
 
   __ EnterFrame(0);
 
-  // Load current Isolate pointer from Context structure into EDI.
-  __ movl(EDI, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadIsolate(EDI);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to dart VM code.
@@ -273,8 +271,7 @@
 
   __ EnterFrame(0);
 
-  // Load current Isolate pointer from Context structure into EDI.
-  __ movl(EDI, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadIsolate(EDI);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to dart VM code.
@@ -995,13 +992,6 @@
     // EDX: number of context variables as integer value (not object).
     __ movl(FieldAddress(EAX, Context::num_variables_offset()), EDX);
 
-    // Setup isolate field.
-    // Load Isolate pointer from Context structure into EBX.
-    // EAX: new object.
-    // EDX: number of context variables.
-    __ movl(FieldAddress(EAX, Context::isolate_offset()),
-            Immediate(reinterpret_cast<int32_t>(isolate)));
-
     const Immediate& raw_null =
         Immediate(reinterpret_cast<intptr_t>(Object::null()));
     // Setup the parent field.
@@ -1794,7 +1784,7 @@
 void StubCode::GenerateDebugStepCheckStub(Assembler* assembler) {
   // Check single stepping.
   Label stepping, done_stepping;
-  __ movl(EAX, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadIsolate(EAX);
   __ movzxb(EAX, Address(EAX, Isolate::single_step_offset()));
   __ cmpl(EAX, Immediate(0));
   __ j(NOT_EQUAL, &stepping, Assembler::kNearJump);
@@ -2056,7 +2046,7 @@
     Assembler* assembler) {
   // Check single stepping.
   Label stepping, done_stepping;
-  __ movl(EAX, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadIsolate(EAX);
   __ movzxb(EAX, Address(EAX, Isolate::single_step_offset()));
   __ cmpl(EAX, Immediate(0));
   __ j(NOT_EQUAL, &stepping);