Port "Add flag to disable lazy compilation of invocation dispatchers."

runtime/vm/stub_code_arm.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 10 matching lines @@
 #define __ assembler->
 
 namespace dart {
 
 DEFINE_FLAG(bool, inline_alloc, true, "Inline allocation of objects.");
 DEFINE_FLAG(bool, use_slow_path, false,
     "Set to true for debugging & verifying the slow paths.");
 DECLARE_FLAG(bool, trace_optimized_ic_calls);
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(bool, support_debugger);
+DECLARE_FLAG(bool, lazy_dispatchers);
 
 // Input parameters:
 //   LR : return address.
 //   SP : address of last argument in argument array.
 //   SP + 4*R4 - 4 : address of first argument in argument array.
 //   SP + 4*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) {
   const intptr_t thread_offset = NativeArguments::thread_offset();
@@ skipping 518 matching lines @@
   __ AddImmediate(LR, -CallPattern::LengthInBytes());
   GenerateDeoptimizationSequence(assembler, true);  // Preserve R0.
 }
 
 
 void StubCode::GenerateDeoptimizeStub(Assembler* assembler) {
   GenerateDeoptimizationSequence(assembler, false);  // Don't preserve R0.
 }
 
 
+static void GenerateDispatcherCode(Assembler* assembler,
+                                   Label* call_target_function) {
+  __ Comment("NoSuchMethodDispatch");
+  // When lazily generated invocation dispatchers are disabled, the
+  // miss-handler may return null.
+  __ CompareObject(R0, Object::null_object());
+  __ b(call_target_function, NE);
+  __ EnterStubFrame();
+  // Load the receiver.
+  __ ldr(R2, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
+  __ add(IP, FP, Operand(R2, LSL, 1));  // R2 is Smi.
+  __ ldr(R6, Address(IP, kParamEndSlotFromFp * kWordSize));
+  __ PushObject(Object::null_object());
+  __ Push(R6);
+  __ Push(R5);
+  __ Push(R4);
+  // R2: Smi-tagged arguments array length.
+  PushArgumentsArray(assembler);
+  const intptr_t kNumArgs = 4;
+  __ CallRuntime(kInvokeNoSuchMethodDispatcherRuntimeEntry, kNumArgs);
+  __ Pop(R0);

[Florian Schneider, 2015/06/17 08:01:34]

I would use 

__ Drop(4);
__ Pop(R0);

for smaller code size.

[rmacnak, 2015/06/17 17:42:20]

Done.

+  __ Pop(R0);
+  __ Pop(R0);
+  __ Pop(R0);
+  __ Pop(R0);  // Return value.
+  __ LeaveStubFrame();
+  __ Ret();
+}
+
+
 void StubCode::GenerateMegamorphicMissStub(Assembler* assembler) {
   __ EnterStubFrame();
 
   // Load the receiver.
   __ ldr(R2, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
   __ add(IP, FP, Operand(R2, LSL, 1));  // R2 is Smi.
   __ ldr(R6, Address(IP, kParamEndSlotFromFp * kWordSize));
 
   // Preserve IC data and arguments descriptor.
   __ PushList((1 << R4) | (1 << R5));
 
   // Push space for the return value.
   // Push the receiver.
   // Push IC data object.
   // Push arguments descriptor array.
   __ LoadImmediate(IP, reinterpret_cast<intptr_t>(Object::null()));
   __ PushList((1 << R4) | (1 << R5) | (1 << R6) | (1 << IP));
   __ CallRuntime(kMegamorphicCacheMissHandlerRuntimeEntry, 3);
   // Remove arguments.
   __ Drop(3);
   __ Pop(R0);  // Get result into R0 (target function).
 
   // Restore IC data and arguments descriptor.
   __ PopList((1 << R4) | (1 << R5));
 
   __ LeaveStubFrame();
 
+  if (!FLAG_lazy_dispatchers) {
+    Label call_target_function;
+    GenerateDispatcherCode(assembler, &call_target_function);
+    __ Bind(&call_target_function);
+  }
+
   // Tail-call to target function.
   __ ldr(R2, FieldAddress(R0, Function::instructions_offset()));
   __ AddImmediate(R2, Instructions::HeaderSize() - kHeapObjectTag);
   __ bx(R2);
 }
 
 
 // Called for inline allocation of arrays.
 // Input parameters:
 //   LR: return address.
@@ skipping 845 matching lines @@
   // Pass IC data object.
   __ Push(R5);
   __ CallRuntime(handle_ic_miss, num_args + 1);
   // Remove the call arguments pushed earlier, including the IC data object.
   __ Drop(num_args + 1);
   // Pop returned function object into R0.
   // Restore arguments descriptor array and IC data array.
   __ PopList((1 << R0) | (1 << R4) | (1 << R5));
   __ LeaveStubFrame();
   Label call_target_function;
-  __ b(&call_target_function);
+  if (!FLAG_lazy_dispatchers) {
+    GenerateDispatcherCode(assembler, &call_target_function);
+  } else {
+    __ b(&call_target_function);
+  }
 
   __ Bind(&found);
   // R6: pointer to an IC data check group.
   const intptr_t target_offset = ICData::TargetIndexFor(num_args) * kWordSize;
   const intptr_t count_offset = ICData::CountIndexFor(num_args) * kWordSize;
   __ LoadFromOffset(kWord, R0, R6, target_offset);
 
   if (FLAG_optimization_counter_threshold >= 0) {
     __ Comment("Update caller's counter");
     __ LoadFromOffset(kWord, R1, R6, count_offset);
@@ skipping 624 matching lines @@
 // Result:
 //  R1: entry point.
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
   EmitMegamorphicLookup(assembler, R0, R1, R1);
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM