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

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index c13c732fbdf6868e39891f0fe34d13ddcf2d0500..8e782158cc68120da5ec8195991899564a596281 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -666,6 +666,133 @@ 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:
+//   o rdi: the JS function object being called
+//   o rsi: our context
+//   o rbp: the caller's frame pointer
+//   o rsp: stack pointer (pointing to return address)
+//
+// The function builds a JS frame.  Please see JavaScriptFrameConstants in
+// frames-x64.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);
+  __ pushq(rbp);  // Caller's frame pointer.
+  __ movp(rbp, rsp);
+  __ Push(rsi);  // Callee's context.
+  __ Push(rdi);  // Callee's JS function.
+
+  // Get the bytecode array from the function object and load the pointer to the
+  // first entry into edi (InterpreterBytecodeRegister).
+  __ movp(r14, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
+  __ movp(r14, FieldOperand(r14, SharedFunctionInfo::kFunctionDataOffset));
+
+  if (FLAG_debug_code) {
+    // Check function data field is actually a BytecodeArray object.
+    __ AssertNotSmi(r14);
+    __ CmpObjectType(r14, BYTECODE_ARRAY_TYPE, rax);
+    __ Assert(equal, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
+  }
+
+  // Allocate the local and temporary register file on the stack.
+  {
+    // Load frame size from the BytecodeArray object.
+    __ movl(rcx, FieldOperand(r14, BytecodeArray::kFrameSizeOffset));
+
+    // Do a stack check to ensure we don't go over the limit.
+    Label ok;
+    __ movp(rdx, rsp);
+    __ subp(rdx, rcx);
+    __ CompareRoot(rdx, Heap::kRealStackLimitRootIndex);
+    __ j(above_equal, &ok, Label::kNear);
+    __ 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(rdx, Heap::kUndefinedValueRootIndex);
+    __ bind(&loop_header);
+    // TODO(rmcilroy): Consider doing more than one push per loop iteration.
+    __ Push(rdx);
+    // Continue loop if not done.
+    __ subp(rcx, Immediate(kPointerSize));
+    __ j(not_equal, &loop_header, Label::kNear);
+  }
+
+  // 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(rsp, Heap::kStackLimitRootIndex);
+    __ j(above_equal, &ok, Label::kNear);
+    __ CallRuntime(Runtime::kStackGuard, 0);
+    __ bind(&ok);
+  }
+
+  // Load bytecode offset and dispatch table into registers.
+  __ movp(r12, Immediate(BytecodeArray::kHeaderSize - kHeapObjectTag));
+  __ LoadRoot(r15, Heap::kInterpreterTableRootIndex);
+  __ addp(r15, Immediate(FixedArray::kHeaderSize - kHeapObjectTag));
+
+  // Dispatch to the first bytecode handler for the function.
+  __ movzxbp(rax, Operand(r14, r12, times_1, 0));
+  __ movp(rax, Operand(r15, rax, times_pointer_size, 0));
+  // TODO(rmcilroy): Make dispatch table point to code entrys to avoid untagging
+  // and header removal.
+  __ addp(rax, Immediate(Code::kHeaderSize - kHeapObjectTag));
+  __ jmp(rax);
+}
+
+
+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 r0.
+  __ movp(rax, Operand(rbp, -kPointerSize -
+                                StandardFrameConstants::kFixedFrameSizeFromFp));
+  // Leave the frame (also dropping the register file).
+  __ leave();
+  // Return droping receiver + arguments.
+  // TODO(rmcilroy): Get number of arguments from BytecodeArray.
+  __ Ret(1 * kPointerSize, rcx);
+}
+
+
 void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
   CallRuntimePassFunction(masm, Runtime::kCompileLazy);
   GenerateTailCallToReturnedCode(masm);