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

src/arm/builtins-arm.cc

Index: src/arm/builtins-arm.cc
diff --git a/src/arm/builtins-arm.cc b/src/arm/builtins-arm.cc
index e3774cb27d50f3b97a9d9f4cdc80ec775d30b789..89e2c109730b7849e12b778cb4901299c979b622 100644
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -10,6 +10,7 @@
 #include "src/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
+#include "src/interpreter/bytecodes.h"
 #include "src/runtime/runtime.h"
 
 namespace v8 {
@@ -869,6 +870,145 @@ 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 r1: the JS function object being called.
+//   o cp: the context
+//   o pp: the caller's constant pool pointer (if enabled)
+//   o fp: the caller's frame pointer
+//   o sp: stack pointer
+//   o lr: return address
+//
+// The function builds a JS frame.  Please see JavaScriptFrameConstants in
+// frames-arm.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);
+
+  __ PushFixedFrame(r1);
+  __ add(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
+
+  // Get the bytecode array from the function object and load the pointer to the
+  // first entry into kInterpreterBytecodeRegister.
+  __ ldr(r0, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
+  __ ldr(kInterpreterBytecodeArrayRegister,
+         FieldMemOperand(r0, SharedFunctionInfo::kFunctionDataOffset));
+
+  if (FLAG_debug_code) {
+    // Check function data field is actually a BytecodeArray object.
+    __ SmiTst(kInterpreterBytecodeArrayRegister);
+    __ Assert(ne, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
+    __ CompareObjectType(kInterpreterBytecodeArrayRegister, r0, no_reg,
+                         BYTECODE_ARRAY_TYPE);
+    __ Assert(eq, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
+  }
+
+  // Allocate the local and temporary register file on the stack.
+  {
+    // Load frame size from the BytecodeArray object.
+    __ ldr(r4, FieldMemOperand(kInterpreterBytecodeArrayRegister,
+                               BytecodeArray::kFrameSizeOffset));
+
+    // Do a stack check to ensure we don't go over the limit.
+    Label ok;
+    __ sub(r9, sp, Operand(r4));
+    __ LoadRoot(r2, Heap::kRealStackLimitRootIndex);
+    __ cmp(r9, Operand(r2));
+    __ 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(r9, Heap::kUndefinedValueRootIndex);
+    __ bind(&loop_header);
+    // TODO(rmcilroy): Consider doing more than one push per loop iteration.
+    __ push(r9);
+    // Continue loop if not done.
+    __ sub(r4, r4, Operand(kPointerSize), SetCC);
+    __ b(&loop_header, ne);
+  }
+
+  // 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.
+  //  - Allocating a new local context if applicable.

[Benedikt Meurer, 2015/07/28 13:06:53]

Note: This should be explicit as in TurboFan.

[rmcilroy, 2015/07/30 07:18:15]

Agreed, this was already my plan :). Rearranged the bullet points to make it
clear which are likely to be explicit bytecodes, and which will be handled in
the entry stub.

+  //  - 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.
+  //  - Supporting FLAG_trace.
+  // These should all either be added here or added as specific bytecodes in the
+  // BytecodeArray.
+
+  // Perform stack guard check.
+  {
+    Label ok;
+    __ LoadRoot(ip, Heap::kStackLimitRootIndex);
+    __ cmp(sp, Operand(ip));
+    __ 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(r0, MemOperand(kInterpreterBytecodeArrayRegister,
+                         kInterpreterBytecodeOffsetRegister));
+  __ mov(r0, Operand(r0, LSL, kPointerSizeLog2));
+  __ ldr(ip, MemOperand(kInterpreterDispatchTableRegister, r0));
+  // TODO(rmcilroy): Make dispatch table point to code entrys to avoid untagging
+  // and header removal.
+  __ add(ip, ip, Operand(Code::kHeaderSize - kHeapObjectTag));
+  __ Jump(ip);
+}
+
+
+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).
+  // These should all either be added here or added as specific bytecodes in the
+  // BytecodeArray.
+
+  // Load return value into r0.
+  __ ldr(r0, MemOperand(fp, -kPointerSize -
+                                StandardFrameConstants::kFixedFrameSizeFromFp));
+  // Leave the frame (also dropping the register file).
+  __ LeaveFrame(StackFrame::JAVA_SCRIPT);
+  // Drop receiver + arguments.
+  __ Drop(1);  // TODO(rmcilroy): Get number of arguments from BytecodeArray.
+  __ Jump(lr);
+}
+
+
 void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
   CallRuntimePassFunction(masm, Runtime::kCompileLazy);
   GenerateTailCallToReturnedCode(masm);