[interpreter] Add Interpreter{Entry,Exit}Trampoline builtins.

src/arm64/builtins-arm64.cc

Index: src/arm64/builtins-arm64.cc
diff --git a/src/arm64/builtins-arm64.cc b/src/arm64/builtins-arm64.cc
index 39bc8d052d277c47196c1ca3af3d5ac7f2104e99..b99431e0de6fad6930566c113f0c9287fdec2485 100644
--- a/src/arm64/builtins-arm64.cc
+++ b/src/arm64/builtins-arm64.cc
@@ -893,6 +893,141 @@ void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
 }
 
 
+// Generate code for entering a JS function with the interpreter.
+// On entry to the function the receiver and arguments have been pushed on the
+// stack left to right.  The actual argument count matches the formal parameter
+// count expected by the function.
+//
+// The live registers are:
+//   - x1: the JS function object being called.
+//   - cp: our context.
+//   - fp: our caller's frame pointer.
+//   - jssp: stack pointer.
+//   - lr: return address.
+//
+// The function builds a JS frame.  Please see JavaScriptFrameConstants in
+// frames-arm64.h for its layout.
+// TODO(rmcilroy): We will need to include the current bytecode pointer in the
+// frame.
+void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
+  // Open a frame scope to indicate that there is a frame on the stack.  The
+  // MANUAL indicates that the scope shouldn't actually generate code to set up
+  // the frame (that is done below).
+  FrameScope frame_scope(masm, StackFrame::MANUAL);
+  __ Push(lr, fp, cp, x1);
+  __ Add(fp, jssp, StandardFrameConstants::kFixedFrameSizeFromFp);
+
+  // Get the bytecode array from the function object and load the pointer to the
+  // first entry into kInterpreterBytecodeRegister.
+  __ Ldr(x0, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
+  __ Ldr(kInterpreterBytecodeArrayRegister,
+         FieldMemOperand(x0, SharedFunctionInfo::kFunctionDataOffset));
+
+  if (FLAG_debug_code) {
+    // Check function data field is actually a BytecodeArray object.
+    __ AssertNotSmi(kInterpreterBytecodeArrayRegister,
+                    kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
+    __ CompareObjectType(kInterpreterBytecodeArrayRegister, x0, x0,
+                         BYTECODE_ARRAY_TYPE);
+    __ Assert(eq, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
+  }
+
+  // Allocate the local and temporary register file on the stack.
+  {
+    // Load frame size from the BytecodeArray object.
+    __ Ldr(w11, FieldMemOperand(kInterpreterBytecodeArrayRegister,
+                                BytecodeArray::kFrameSizeOffset));
+
+    // Do a stack check to ensure we don't go over the limit.
+    Label ok;
+    DCHECK(jssp.Is(__ StackPointer()));
+    __ Sub(x10, jssp, Operand(x11));
+    __ CompareRoot(x10, Heap::kRealStackLimitRootIndex);
+    __ B(hs, &ok);
+    __ InvokeBuiltin(Builtins::STACK_OVERFLOW, CALL_FUNCTION);
+    __ Bind(&ok);
+
+    // If ok, push undefined as the initial value for all register file entries.
+    // Note: there should always be at least one stack slot for the return
+    // register in the register file.
+    Label loop_header;
+    __ LoadRoot(x10, Heap::kUndefinedValueRootIndex);
+    // TODO(rmcilroy): Ensure we always have an even number of registers to
+    // allow stack to be 16 bit aligned (and remove need for jssp).
+    __ Lsr(x11, x11, kPointerSizeLog2);
+    __ PushMultipleTimes(x10, x11);
+    __ Bind(&loop_header);
+  }
+
+  // TODO(rmcilroy): List of things not currently dealt with here but done in
+  // fullcodegen's prologue:
+  //  - Support profiler (specifically profiling_counter).
+  //  - Call ProfileEntryHookStub when isolate has a function_entry_hook.
+  //  - Allow simulator stop operations if FLAG_stop_at is set.
+  //  - Deal with sloppy mode functions which need to replace the
+  //    receiver with the global proxy when called as functions (without an
+  //    explicit receiver object).
+  //  - Code aging of the BytecodeArray object.
+  //  - Supporting FLAG_trace.
+  //
+  // The following items are also not done here, and will probably be done using
+  // explicit bytecodes instead:
+  //  - Allocating a new local context if applicable.
+  //  - Setting up a local binding to the this function, which is used in
+  //    derived constructors with super calls.
+  //  - Setting new.target if required.
+  //  - Dealing with REST parameters (only if
+  //    https://codereview.chromium.org/1235153006 doesn't land by then).
+  //  - Dealing with argument objects.
+
+  // Perform stack guard check.
+  {
+    Label ok;
+    __ CompareRoot(jssp, Heap::kStackLimitRootIndex);
+    __ B(hs, &ok);
+    __ CallRuntime(Runtime::kStackGuard, 0);
+    __ Bind(&ok);
+  }
+
+  // Load bytecode offset and dispatch table into registers.
+  __ Mov(kInterpreterBytecodeOffsetRegister,
+         Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
+  __ LoadRoot(kInterpreterDispatchTableRegister,
+              Heap::kInterpreterTableRootIndex);
+  __ Add(kInterpreterDispatchTableRegister, kInterpreterDispatchTableRegister,
+         Operand(FixedArray::kHeaderSize - kHeapObjectTag));
+
+  // Dispatch to the first bytecode handler for the function.
+  __ Ldrb(x0, MemOperand(kInterpreterBytecodeArrayRegister,
+                         kInterpreterBytecodeOffsetRegister));
+  __ Mov(x0, Operand(x0, LSL, kPointerSizeLog2));
+  __ Ldr(ip0, MemOperand(kInterpreterDispatchTableRegister, x0));
+  // TODO(rmcilroy): Make dispatch table point to code entrys to avoid untagging
+  // and header removal.
+  __ Add(ip0, ip0, Operand(Code::kHeaderSize - kHeapObjectTag));
+  __ Jump(ip0);
+}
+
+
+void Builtins::Generate_InterpreterExitTrampoline(MacroAssembler* masm) {
+  // TODO(rmcilroy): List of things not currently dealt with here but done in
+  // fullcodegen's EmitReturnSequence.
+  //  - Supporting FLAG_trace for Runtime::TraceExit.
+  //  - Support profiler (specifically decrementing profiling_counter
+  //    appropriately and calling out to HandleInterrupts if necessary).
+
+  // Load return value into x0.
+  __ ldr(x0, MemOperand(fp, -kPointerSize -
+                                StandardFrameConstants::kFixedFrameSizeFromFp));
+  // Leave the frame (also dropping the register file).
+  __ LeaveFrame(StackFrame::JAVA_SCRIPT);
+  // Drop receiver + arguments.
+  // TODO(rmcilroy): Get number of arguments from BytecodeArray.
+  __ Drop(1, kXRegSize);
+  __ Ret();
+}
+
+
 void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
   CallRuntimePassFunction(masm, Runtime::kCompileLazy);
   GenerateTailCallToReturnedCode(masm);