Compile and simulate first dart function on arm generated from ast.

runtime/vm/stub_code_arm.cc

Index: runtime/vm/stub_code_arm.cc
===================================================================
--- runtime/vm/stub_code_arm.cc	(revision 19074)
+++ runtime/vm/stub_code_arm.cc	(working copy)
@@ -5,6 +5,11 @@
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM)
 
+#include "vm/assembler.h"
+#include "vm/assembler_macros.h"
+#include "vm/dart_entry.h"
+#include "vm/instructions.h"
+#include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 
 #define __ assembler->
@@ -66,8 +71,133 @@
 }
 
 
+// Called when invoking Dart code from C++ (VM code).
+// Input parameters:
+//   LR : points to return address.
+//   R0 : entrypoint of the Dart function to call.
+//   R1 : arguments descriptor array.
+//   R2 : arguments array.
+//   R3 : new context containing the current isolate pointer.
 void StubCode::GenerateInvokeDartCodeStub(Assembler* assembler) {
-  __ Unimplemented("InvokeDartCode stub");
+  // Save frame pointer coming in.
+  AssemblerMacros::EnterStubFrame(assembler);
+
+  // Save new context and C++ ABI callee-saved registers.
+  const intptr_t kNewContextOffset = -(1 + kAbiPreservedRegCount) * kWordSize;
+  __ PushList((1 << R3) | kAbiPreservedRegs);
+
+  // The new Context structure contains a pointer to the current Isolate
+  // structure. Cache the Context pointer in the CTX register so that it is
+  // available in generated code and calls to Isolate::Current() need not be
+  // done. The assumption is that this register will never be clobbered by
+  // compiled or runtime stub code.
+
+  // Cache the new Context pointer into CTX while executing Dart code.
+  __ ldr(CTX, Address(R3, VMHandles::kOffsetOfRawPtrInHandle));
+
+  // Load Isolate pointer from Context structure into temporary register R8.
+  __ ldr(R8, FieldAddress(CTX, Context::isolate_offset()));
+
+  // Save the top exit frame info. Use R5 as a temporary register.
+  // StackFrameIterator reads the top exit frame info saved in this frame.
+  {
+    // TODO(regis): Add assembler macro for {Load,Store}BasedOffset with no
+    // restriction on the offset.
+    const intptr_t offset = Isolate::top_exit_frame_info_offset();
+    const int32_t offset12_hi = offset & ~kOffset12Mask;  // signed
+    const uint32_t offset12_lo = offset & kOffset12Mask;  // unsigned
+    __ AddImmediate(R7, R8, offset12_hi);
+    __ ldr(R5, Address(R7, offset12_lo));
+    __ LoadImmediate(R6, 0);
+    __ str(R6, Address(R7, offset12_lo));
+  }
+
+  // Save the old Context pointer. Use R4 as a temporary register.
+  // Note that VisitObjectPointers will find this saved Context pointer during
+  // GC marking, since it traverses any information between SP and
+  // FP - kExitLinkOffsetInEntryFrame.
+  // EntryFrame::SavedContext reads the context saved in this frame.
+  {
+    const intptr_t offset = Isolate::top_context_offset();
+    const int32_t offset12_hi = offset & ~kOffset12Mask;  // signed
+    const uint32_t offset12_lo = offset & kOffset12Mask;  // unsigned
+    __ AddImmediate(R7, R8, offset12_hi);
+    __ ldr(R4, Address(R7, offset12_lo));
+  }
+
+  // The constants kSavedContextOffsetInEntryFrame and
+  // kExitLinkOffsetInEntryFrame must be kept in sync with the code below.
+  __ PushList((1 << R4) | (1 << R5));
+
+  // The stack pointer is restore after the call to this location.
+  const intptr_t kSavedContextOffsetInEntryFrame = -10 * kWordSize;
+
+  // Load arguments descriptor array into R4, which is passed to Dart code.
+  __ ldr(R4, Address(R1, VMHandles::kOffsetOfRawPtrInHandle));
+
+  // Load number of arguments into R5.
+  __ ldr(R5, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
+  __ SmiUntag(R5);
+
+  // Compute address of 'arguments array' data area into R2.
+  __ ldr(R2, Address(R2, VMHandles::kOffsetOfRawPtrInHandle));
+  __ AddImmediate(R2, R2, Array::data_offset() - kHeapObjectTag);
+
+  // Set up arguments for the Dart call.
+  Label push_arguments;
+  Label done_push_arguments;
+  __ CompareImmediate(R5, 0);  // check if there are arguments.
+  __ b(&done_push_arguments, EQ);
+  __ LoadImmediate(R1, 0);
+  __ Bind(&push_arguments);
+  __ ldr(R3, Address(R2));
+  __ Push(R3);
+  __ AddImmediate(R2, kWordSize);
+  __ AddImmediate(R1, 1);
+  __ cmp(R1, ShifterOperand(R5));
+  __ b(&push_arguments, LT);
+  __ Bind(&done_push_arguments);
+
+  // Call the Dart code entrypoint.
+  __ blx(R0);  // R4 is the arguments descriptor array.
+
+  // Read the saved new Context pointer.
+  __ ldr(CTX, Address(FP, kNewContextOffset));
+  __ ldr(CTX, Address(CTX, VMHandles::kOffsetOfRawPtrInHandle));
+
+  // Get rid of arguments pushed on the stack.
+  __ AddImmediate(SP, FP, kSavedContextOffsetInEntryFrame);
+
+  // Load Isolate pointer from Context structure into CTX. Drop Context.
+  __ ldr(CTX, FieldAddress(CTX, Context::isolate_offset()));
+
+  // Restore the saved Context pointer into the Isolate structure.
+  // Uses R4 as a temporary register for this.
+  // Restore the saved top exit frame info back into the Isolate structure.
+  // Uses R5 as a temporary register for this.
+  __ PopList((1 << R4) | (1 << R5));
+  {
+    const intptr_t offset = Isolate::top_context_offset();
+    const int32_t offset12_hi = offset & ~kOffset12Mask;  // signed
+    const uint32_t offset12_lo = offset & kOffset12Mask;  // unsigned
+    __ AddImmediate(R7, CTX, offset12_hi);
+    __ str(R4, Address(R7, offset12_lo));
+  }
+  {
+    const intptr_t offset = Isolate::top_exit_frame_info_offset();
+    const int32_t offset12_hi = offset & ~kOffset12Mask;  // signed
+    const uint32_t offset12_lo = offset & kOffset12Mask;  // unsigned
+    __ AddImmediate(R7, CTX, offset12_hi);
+    __ str(R5, Address(R7, offset12_lo));
+  }
+
+  // Restore C++ ABI callee-saved registers.
+  __ PopList((1 << R3) | kAbiPreservedRegs);  // Ignore restored R3.
+
+  // Restore the frame pointer.
+  AssemblerMacros::LeaveStubFrame(assembler);
+
+  __ Ret();
 }