Count-based profiling for primitive functions (hidden behind a flag)

src/arm/full-codegen-arm.cc

-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
@@ skipping 120 matching lines @@
   SetFunctionPosition(function());
   Comment cmnt(masm_, "[ function compiled by full code generator");
 
 #ifdef DEBUG
   if (strlen(FLAG_stop_at) > 0 &&
       info->function()->name()->IsEqualTo(CStrVector(FLAG_stop_at))) {
     __ stop("stop-at");
   }
 #endif
 
+  // Primitive functions are unlikely to be picked up by the stack-walking
+  // profiler, so they trigger their own optimization when they're called
+  // for the SharedFunctionInfo::kCallsUntilPrimitiveOptimization-th time.

[Erik Corry, 2012/02/09 09:43:33]

I think this comment should be moved into ShouldSelfOptimize, where it actually
describes the logic used to make the decision.  Then it is in the right place
for when we change the heuristic.

Here we should have a more generic comment like:

// We can optionally optimize based on counters rather than statistical
sampling.

[Jakob Kummerow, 2012/02/09 10:13:20]

Done.

+  if (info->ShouldSelfOptimize()) {
+    if (FLAG_trace_opt) {

[Erik Corry, 2012/02/09 09:43:33]

I think this might be annoyingly verbose, but we can add a trace-opt-verbose
flag later if we need to.

[Jakob Kummerow, 2012/02/09 10:13:20]

As discussed, let's leave it for now. We can always remove it later.

+      PrintF("[adding self-optimization header to %s]\n",
+             *info->function()->debug_name()->ToCString());
+    }
+    MaybeObject* maybe_cell = isolate()->heap()->AllocateJSGlobalPropertyCell(
+        Smi::FromInt(Compiler::kCallsUntilPrimitiveOpt));
+    JSGlobalPropertyCell* cell;
+    if (maybe_cell->To(&cell)) {
+      __ mov(r2, Operand(Handle<JSGlobalPropertyCell>(cell)));
+      __ ldr(r3, FieldMemOperand(r2, JSGlobalPropertyCell::kValueOffset));
+      __ sub(r3, r3, Operand(Smi::FromInt(1)), SetCC);
+      __ str(r3, FieldMemOperand(r2, JSGlobalPropertyCell::kValueOffset));
+      Handle<Code> compile_stub(
+          isolate()->builtins()->builtin(Builtins::kLazyRecompile));
+      __ Jump(compile_stub, RelocInfo::CODE_TARGET, eq);
+    }
+  }
+
   // Strict mode functions and builtins need to replace the receiver
   // with undefined when called as functions (without an explicit
   // receiver object). r5 is zero for method calls and non-zero for
   // function calls.
   if (!info->is_classic_mode() || info->is_native()) {
     Label ok;
     __ cmp(r5, Operand(0));
     __ b(eq, &ok);
     int receiver_offset = info->scope()->num_parameters() * kPointerSize;
     __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
@@ skipping 4251 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM