Adds Runtime call stub and Dart entry stub to ARM64.

runtime/vm/stub_code_arm64.cc

Index: runtime/vm/stub_code_arm64.cc
===================================================================
--- runtime/vm/stub_code_arm64.cc	(revision 35189)
+++ runtime/vm/stub_code_arm64.cc	(working copy)
@@ -21,8 +21,105 @@
 
 namespace dart {
 
+// Input parameters:
+//   LR : return address.
+//   SP : address of last argument in argument array.
+//   SP + 8*R4 - 8 : address of first argument in argument array.
+//   SP + 8*R4 : address of return value.
+//   R5 : address of the runtime function to call.
+//   R4 : number of arguments to the call.
 void StubCode::GenerateCallToRuntimeStub(Assembler* assembler) {
-  __ Stop("GenerateCallToRuntimeStub");
+  const intptr_t isolate_offset = NativeArguments::isolate_offset();
+  const intptr_t argc_tag_offset = NativeArguments::argc_tag_offset();
+  const intptr_t argv_offset = NativeArguments::argv_offset();
+  const intptr_t retval_offset = NativeArguments::retval_offset();
+  const intptr_t exitframe_last_param_slot_from_fp = 1;
+
+  __ SetPrologueOffset();
+  __ Comment("CallToRuntimeStub");
+  __ EnterFrame(0);
+
+  // Load current Isolate pointer from Context structure into A0.
+  __ LoadFieldFromOffset(R0, CTX, Context::isolate_offset());
+
+  // Save exit frame information to enable stack walking as we are about
+  // to transition to Dart VM C++ code.
+  __ StoreToOffset(SP, R0, Isolate::top_exit_frame_info_offset());
+
+  // Save current Context pointer into Isolate structure.
+  __ StoreToOffset(CTX, R0, Isolate::top_context_offset());
+
+  // Cache Isolate pointer into CTX while executing runtime code.
+  __ mov(CTX, R0);
+
+#if defined(DEBUG)
+  { Label ok;
+    // Check that we are always entering from Dart code.
+    __ LoadFromOffset(R8, R0, Isolate::vm_tag_offset());
+    __ CompareImmediate(R8, VMTag::kScriptTagId, kNoRegister);
+    __ b(&ok, EQ);
+    __ Stop("Not coming from Dart code.");
+    __ Bind(&ok);
+  }
+#endif
+
+  // Mark that the isolate is executing VM code.
+  __ StoreToOffset(R5, R0, Isolate::vm_tag_offset());
+
+  // Reserve space for arguments and align frame before entering C++ world.
+  // NativeArguments are passed in registers.
+  __ Comment("align stack");
+  ASSERT(sizeof(NativeArguments) == 4 * kWordSize);
+  __ ReserveAlignedFrameSpace(4 * kWordSize);  // Reserve space for arguments.
+
+  // Pass NativeArguments structure by value and call runtime.
+  // Registers R0, R1, R2, and R3 are used.
+
+  ASSERT(isolate_offset == 0 * kWordSize);
+  // Set isolate in NativeArgs: R0 already contains CTX.
+
+  // There are no runtime calls to closures, so we do not need to set the tag
+  // bits kClosureFunctionBit and kInstanceFunctionBit in argc_tag_.
+  ASSERT(argc_tag_offset == 1 * kWordSize);
+  __ mov(R1, R4);  // Set argc in NativeArguments.
+
+  ASSERT(argv_offset == 2 * kWordSize);
+  __ add(R2, ZR, Operand(R4, LSL, 3));
+  __ add(R2, FP, Operand(R2));  // Compute argv.
+  // Set argv in NativeArguments.
+  __ AddImmediate(R2, R2, exitframe_last_param_slot_from_fp * kWordSize,
+                  kNoRegister);
+
+    ASSERT(retval_offset == 3 * kWordSize);
+  __ AddImmediate(R3, R2, kWordSize, kNoRegister);
+
+  // TODO(zra): Check that the ABI allows calling through this register.
+  __ blr(R5);
+
+  // Retval is next to 1st argument.
+  __ Comment("CallToRuntimeStub return");
+
+  // Mark that the isolate is executing Dart code.
+  __ LoadImmediate(R2, VMTag::kScriptTagId, kNoRegister);
+  __ StoreToOffset(R2, CTX, Isolate::vm_tag_offset());
+
+  // Reset exit frame information in Isolate structure.
+  __ StoreToOffset(ZR, CTX, Isolate::top_exit_frame_info_offset());
+
+  // Load Context pointer from Isolate structure into A2.
+  __ LoadFromOffset(R2, CTX, Isolate::top_context_offset());
+
+  // Load null.
+  __ LoadObject(TMP, Object::null_object(), PP);
+
+  // Reset Context pointer in Isolate structure.
+  __ StoreToOffset(TMP, CTX, Isolate::top_context_offset());
+
+  // Cache Context pointer into CTX while executing Dart code.
+  __ mov(CTX, R2);
+
+  __ LeaveFrame();
+  __ ret();
 }
 
 
@@ -71,8 +168,154 @@
 }
 
 
+// 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) {
-  __ Stop("GenerateInvokeDartCodeStub");
+  __ Comment("InvokeDartCodeStub");
+  __ EnterFrame(0);
+
+  // The new context, saved vm tag, the top exit frame, and the old context.
+  // const intptr_t kPreservedContextSlots = 4;
+  const intptr_t kNewContextOffsetFromFp =
+      -(1 + kAbiPreservedCpuRegCount) * kWordSize;
+  // const intptr_t kPreservedRegSpace =
+  //     kWordSize * (kAbiPreservedCpuRegCount + kPreservedContextSlots);
+
+  // Save the callee-saved registers.
+  for (int i = R19; i <= R28; i++) {
+    const Register r = static_cast<Register>(i);
+    // We use str instead of the Push macro because we will be pushing the PP
+    // register when it is not holding a pool-pointer since we are coming from
+    // C++ code.
+    __ str(r, Address(SP, -1 * kWordSize, Address::PreIndex));
+  }
+
+  // TODO(zra): Save the bottom 64-bits of callee-saved floating point
+  // registers.
+
+  // Push new context.
+  __ Push(R3);
+
+  // We now load the pool pointer(PP) as we are about to invoke dart code and we
+  // could potentially invoke some intrinsic functions which need the PP to be
+  // set up.
+  __ LoadPoolPointer(PP);
+
+  // 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.
+  __ LoadFromOffset(CTX, R3, VMHandles::kOffsetOfRawPtrInHandle);
+
+  // Load Isolate pointer from Context structure into temporary register R4.
+  __ LoadFieldFromOffset(R5, CTX, Context::isolate_offset());
+
+  // Save the current VMTag on the stack.
+  ASSERT(kSavedVMTagSlotFromEntryFp == -12);
+  __ LoadFromOffset(R4, R5, Isolate::vm_tag_offset());
+  __ Push(R4);
+
+  // Mark that the isolate is executing Dart code.
+  __ LoadImmediate(R6, VMTag::kScriptTagId, PP);
+  __ StoreToOffset(R6, R5, Isolate::vm_tag_offset());
+
+  // Save the top exit frame info. Use R6 as a temporary register.
+  // StackFrameIterator reads the top exit frame info saved in this frame.
+  __ LoadFromOffset(R6, R5, Isolate::top_exit_frame_info_offset());
+  __ StoreToOffset(ZR, R5, Isolate::top_exit_frame_info_offset());
+
+  // 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 - kExitLinkSlotFromEntryFp.
+  // EntryFrame::SavedContext reads the context saved in this frame.
+  __ LoadFromOffset(R4, R5, Isolate::top_context_offset());
+
+  // The constants kSavedContextSlotFromEntryFp and
+  // kExitLinkSlotFromEntryFp must be kept in sync with the code below.
+  ASSERT(kExitLinkSlotFromEntryFp == -13);
+  ASSERT(kSavedContextSlotFromEntryFp == -14);
+  __ Push(R6);
+  __ Push(R4);
+
+  // Load arguments descriptor array into R4, which is passed to Dart code.
+  __ LoadFromOffset(R4, R1, VMHandles::kOffsetOfRawPtrInHandle);
+
+  // Load number of arguments into S5.
+  __ LoadFieldFromOffset(R5, R4, ArgumentsDescriptor::count_offset());
+  __ SmiUntag(R5);
+
+  // Compute address of 'arguments array' data area into R2.
+  __ LoadFromOffset(R2, R2, VMHandles::kOffsetOfRawPtrInHandle);
+  __ AddImmediate(R2, R2, Array::data_offset() - kHeapObjectTag, PP);
+
+  // Set up arguments for the Dart call.
+  Label push_arguments;
+  Label done_push_arguments;
+  __ cmp(R5, Operand(0));
+  __ b(&done_push_arguments, EQ);  // check if there are arguments.
+  __ LoadImmediate(R1, 0, PP);
+  __ Bind(&push_arguments);
+  __ ldr(R3, Address(R2));
+  __ Push(R3);
+  __ add(R1, R1, Operand(1));
+  __ add(R2, R2, Operand(kWordSize));
+  __ cmp(R1, Operand(R5));
+  __ b(&push_arguments, LT);
+  __ Bind(&done_push_arguments);
+
+  // Call the Dart code entrypoint.
+  __ blr(R0);  // R4 is the arguments descriptor array.
+  __ Comment("InvokeDartCodeStub return");
+
+  // Read the saved new Context pointer.
+  __ LoadFromOffset(CTX, FP, kNewContextOffsetFromFp);
+  __ LoadFromOffset(CTX, CTX, VMHandles::kOffsetOfRawPtrInHandle);
+
+  // Get rid of arguments pushed on the stack.
+  __ AddImmediate(SP, FP, kSavedContextSlotFromEntryFp * kWordSize, PP);
+
+  // Load Isolate pointer from Context structure into CTX. Drop Context.
+  __ LoadFieldFromOffset(CTX, CTX, Context::isolate_offset());
+
+  // Restore the current VMTag from the stack.
+  __ ldr(R4, Address(SP, 2 * kWordSize));
+  __ StoreToOffset(R4, CTX, Isolate::vm_tag_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 R6 as a temporary register for this.
+  __ Pop(R4);
+  __ Pop(R6);
+  __ StoreToOffset(R4, CTX, Isolate::top_context_offset());
+  __ StoreToOffset(R6, CTX, Isolate::top_exit_frame_info_offset());
+
+  __ Pop(R3);
+  __ Pop(R4);
+
+  // Restore C++ ABI callee-saved registers.
+  for (int i = R28; i >= R19; i--) {
+    Register r = static_cast<Register>(i);
+    // We use ldr instead of the Pop macro because we will be popping the PP
+    // register when it is not holding a pool-pointer since we are returning to
+    // C++ code.
+    __ ldr(r, Address(SP, 1 * kWordSize, Address::PostIndex));
+  }
+
+  // TODO(zra): Restore callee-saved fpu registers.
+
+  // Restore the frame pointer and return.
+  __ LeaveFrame();
+  __ ret();
 }