In optimized code use IC calls for instance calls that have no IC data instead of deoptimizing. The…

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2012, 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_X64)
 
 #include "vm/assembler.h"
 #include "vm/assembler_macros.h"
 #include "vm/compiler.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/instructions.h"
 #include "vm/object_store.h"
 #include "vm/pages.h"
 #include "vm/resolver.h"
 #include "vm/scavenger.h"
 #include "vm/stub_code.h"
 
 
 #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(int, optimization_counter_threshold);
+DECLARE_FLAG(bool, trace_optimized_ic_calls);
 
 // Input parameters:
 //   RSP : points to return address.
 //   RSP + 8 : address of last argument in argument array.
 //   RSP + 8*R10 : address of first argument in argument array.
 //   RSP + 8*R10 + 8 : address of return value.
 //   RBX : address of the runtime function to call.
 //   R10 : number of arguments to the call.
 // Must preserve callee saved registers R12 and R13.
 void StubCode::GenerateCallToRuntimeStub(Assembler* assembler) {
@@ skipping 1479 matching lines @@
   __ popq(RAX);
   __ popq(RAX);
   __ popq(RAX);  // Get result into RAX.
 
   // Remove the stub frame as we are about to return.
   __ LeaveFrame();
   __ ret();
 }
 
 
+void StubCode::GenerateOptimizedUsageCounterIncrement(Assembler* assembler) {
+  Register argdesc_reg = R10;
+  Register ic_reg = RBX;
+  Register func_reg = RDI;
+  if (FLAG_trace_optimized_ic_calls) {
+    AssemblerMacros::EnterStubFrame(assembler);
+    __ pushq(func_reg);     // Preserve
+    __ pushq(argdesc_reg);  // Preserve.
+    __ pushq(ic_reg);       // Preserve.
+    __ pushq(ic_reg);       // Argument.
+    __ pushq(func_reg);     // Argument.
+    __ CallRuntime(kTraceICCallRuntimeEntry);
+    __ popq(RAX);          // Discard argument;
+    __ popq(RAX);          // Discard argument;
+    __ popq(ic_reg);       // Restore.
+    __ popq(argdesc_reg);  // Restore.
+    __ popq(func_reg);     // Restore.
+    __ LeaveFrame();
+  }
+  Label is_hot;
+  if (FlowGraphCompiler::CanOptimize()) {
+    ASSERT(FLAG_optimization_counter_threshold > 1);
+    __ cmpq(FieldAddress(func_reg, Function::usage_counter_offset()),
+        Immediate(FLAG_optimization_counter_threshold));
+    __ j(GREATER_EQUAL, &is_hot, Assembler::kNearJump);
+    // As long as VM has no OSR do not optimize in the middle of the function
+    // but only at exit so that we have collected all type feedback before
+    // optimizing.
+  }
+  __ incq(FieldAddress(func_reg, Function::usage_counter_offset()));
+  __ Bind(&is_hot);
+}
+
+
 // Loads function into 'temp_reg', preserves 'ic_reg'.
 void StubCode::GenerateUsageCounterIncrement(Assembler* assembler,
-                                             Register ic_reg,
                                              Register temp_reg) {
-  __ movq(temp_reg, FieldAddress(ic_reg, ICData::function_offset()));
+  Register ic_reg = RBX;
+  Register func_reg = temp_reg;
+  ASSERT(ic_reg != func_reg);
+  __ movq(func_reg, FieldAddress(ic_reg, ICData::function_offset()));
   Label is_hot;
   if (FlowGraphCompiler::CanOptimize()) {
     ASSERT(FLAG_optimization_counter_threshold > 1);
     // The usage_counter is always less than FLAG_optimization_counter_threshold
     // except when the function gets optimized.
-    __ cmpq(FieldAddress(temp_reg, Function::usage_counter_offset()),
+    __ cmpq(FieldAddress(func_reg, Function::usage_counter_offset()),
         Immediate(FLAG_optimization_counter_threshold));
     __ j(EQUAL, &is_hot, Assembler::kNearJump);
     // As long as VM has no OSR do not optimize in the middle of the function
     // but only at exit so that we have collected all type feedback before
     // optimizing.
   }
-  __ incq(FieldAddress(temp_reg, Function::usage_counter_offset()));
+  __ incq(FieldAddress(func_reg, Function::usage_counter_offset()));
   __ Bind(&is_hot);
 }
 
 // Generate inline cache check for 'num_args'.
 //  RBX: Inline cache data object.
 //  R10: Arguments descriptor array.
 //  TOS(0): return address
 // Control flow:
 // - If receiver is null -> jump to IC miss.
 // - If receiver is Smi -> load Smi class.
@@ skipping 98 matching lines @@
     __ popq(RAX);
   }
   __ popq(RAX);  // Pop returned code object into RAX (null if not found).
   __ popq(RBX);  // Restore IC data array.
   __ popq(R10);  // Restore arguments array.
   __ LeaveFrame();
   Label call_target_function;
   __ cmpq(RAX, raw_null);
   __ j(NOT_EQUAL, &call_target_function, Assembler::kNearJump);
   // NoSuchMethod or closure.
+  // Mark IC call that it may be a closure call that does not collect
+  // type feedback.
+  __ movb(FieldAddress(RBX, ICData::is_closure_call_offset()), Immediate(1));
   __ jmp(&StubCode::InstanceFunctionLookupLabel());
 
   __ Bind(&found);
   // R12: Pointer to an IC data check group (classes + target)
   __ movq(RAX, Address(R12, kWordSize * num_args));  // Target function.
 
   __ Bind(&call_target_function);
   // RAX: Target function.
   __ movq(RAX, FieldAddress(RAX, Function::code_offset()));
   __ movq(RAX, FieldAddress(RAX, Code::instructions_offset()));
@@ skipping 20 matching lines @@
 //  RBX: Inline cache data object.
 //  RDX: Arguments array.
 //  TOS(0): Return address.
 // Inline cache data object structure:
 // 0: function-name
 // 1: N, number of arguments checked.
 // 2 .. (length - 1): group of checks, each check containing:
 //   - N classes.
 //   - 1 target function.
 void StubCode::GenerateOneArgCheckInlineCacheStub(Assembler* assembler) {
-  GenerateUsageCounterIncrement(assembler, RBX, RCX);
-  return GenerateNArgsCheckInlineCacheStub(assembler, 1);
+  GenerateUsageCounterIncrement(assembler, RCX);
+  GenerateNArgsCheckInlineCacheStub(assembler, 1);
 }
 
 
 void StubCode::GenerateTwoArgsCheckInlineCacheStub(Assembler* assembler) {
-  GenerateUsageCounterIncrement(assembler, RBX, RCX);
-  return GenerateNArgsCheckInlineCacheStub(assembler, 2);
+  GenerateUsageCounterIncrement(assembler, RCX);
+  GenerateNArgsCheckInlineCacheStub(assembler, 2);
 }
 
 
 void StubCode::GenerateThreeArgsCheckInlineCacheStub(Assembler* assembler) {
-  GenerateUsageCounterIncrement(assembler, RBX, RCX);
-  return GenerateNArgsCheckInlineCacheStub(assembler, 3);
+  GenerateUsageCounterIncrement(assembler, RCX);
+  GenerateNArgsCheckInlineCacheStub(assembler, 3);
 }
 
+// Use inline cache data array to invoke the target or continue in inline
+// cache miss handler. Stub for 1-argument check (receiver class).
+//  RDI: function which counter needs to be incremented.
+//  RBX: Inline cache data object.
+//  RDX: Arguments array.
+//  TOS(0): Return address.
+// Inline cache data object structure:
+// 0: function-name
+// 1: N, number of arguments checked.
+// 2 .. (length - 1): group of checks, each check containing:
+//   - N classes.
+//   - 1 target function.
+void StubCode::GenerateOneArgOptimizedCheckInlineCacheStub(
+    Assembler* assembler) {
+  GenerateOptimizedUsageCounterIncrement(assembler);
+  GenerateNArgsCheckInlineCacheStub(assembler, 1);
+}
+
+
+void StubCode::GenerateTwoArgsOptimizedCheckInlineCacheStub(
+    Assembler* assembler) {
+  GenerateOptimizedUsageCounterIncrement(assembler);
+  GenerateNArgsCheckInlineCacheStub(assembler, 2);
+}
+
+
+void StubCode::GenerateThreeArgsOptimizedCheckInlineCacheStub(
+    Assembler* assembler) {
+  GenerateOptimizedUsageCounterIncrement(assembler);
+  GenerateNArgsCheckInlineCacheStub(assembler, 3);
+}
+
+
+// Do not count as no type feedback is collected.
+void StubCode::GenerateClosureCallInlineCacheStub(Assembler* assembler) {
+  GenerateNArgsCheckInlineCacheStub(assembler, 1);
+}
+
+
 // Megamorphic call is currently implemented as IC call but through a stub
 // that does not check/count function invocations.
 void StubCode::GenerateMegamorphicCallStub(Assembler* assembler) {
-  return GenerateNArgsCheckInlineCacheStub(assembler, 1);
+  GenerateNArgsCheckInlineCacheStub(assembler, 1);
 }
 
 //  RBX: Function object.
 //  R10: Arguments array.
 //  TOS(0): return address (Dart code).
 void StubCode::GenerateBreakpointStaticStub(Assembler* assembler) {
   AssemblerMacros::EnterStubFrame(assembler);
   __ pushq(R10);
   __ pushq(RBX);
   __ CallRuntime(kBreakpointStaticHandlerRuntimeEntry);
@@ skipping 307 matching lines @@
   __ CallRuntime(kOptimizeInvokedFunctionRuntimeEntry);
   __ popq(RDX);
   __ popq(RAX);
   __ LeaveFrame();
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64