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

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 135db06ac84d556ce78a01abeb74993282587a6a..9f9636580e49803300ba083266ff78ca20b029af 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -1,4 +1,4 @@
-// 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:
@@ -129,6 +129,32 @@ void FullCodeGenerator::Generate(CompilationInfo* info) {
   }
 #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.
+  if (FLAG_counting_profiler &&

[Erik Corry, 2012/02/08 14:09:23]

These two flags can be tested inside ShouldSelfOptimize for a reduction in
verbosity.  Perhaps the flags on the shared info can also be tested there?

[Jakob Kummerow, 2012/02/08 15:24:08]

Good idea to clean this up. I've moved ShouldSelfOptimize() to CompilationInfo,
where all the required information for this decision is accessible.

+      FLAG_crankshaft &&
+      info->function()->ShouldSelfOptimize() &&
+      !Serializer::enabled() &&
+      !(!info->shared_info().is_null() &&
+        info->shared_info()->optimization_disabled())) {
+    if (FLAG_trace_opt) {
+      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(eax, Immediate(Handle<JSGlobalPropertyCell>(cell)));
+      __ sub(FieldOperand(eax, JSGlobalPropertyCell::kValueOffset),
+             Immediate(Smi::FromInt(1)));

[Erik Corry, 2012/02/08 14:09:23]

It seems you can do:

__ sub(Operand::Cell(Handle<JSGlobalPropertyCell>(cell)), Immediate(...))

[Jakob Kummerow, 2012/02/08 15:24:08]

Done.

+      Handle<Code> compile_stub(
+          isolate()->builtins()->builtin(Builtins::kLazyRecompile));
+      __ j(zero, compile_stub);

[Erik Corry, 2012/02/08 14:09:23]

There is an assumption here that the Smi tag is zero and that we decrement one
at a time.  I would prefer j(mi, ... instead.

[Jakob Kummerow, 2012/02/08 15:24:08]

I've added an ASSERT for the Smi tag.
I can't easily change the jump condition because we intentionally don't reset
the countdown. After it has fired,  should we ever come back (e.g. after deopt),
we simply ignore it (until it overflows and reaches zero again after 2 billion
executions).

+    }
+  }
+
   // Strict mode functions and builtins need to replace the receiver
   // with undefined when called as functions (without an explicit
   // receiver object). ecx is zero for method calls and non-zero for