[wasm] Adding metrics for Asm/Wasm.

src/wasm/wasm-js.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api.h"
 #include "src/api-natives.h"
 #include "src/assert-scope.h"
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/factory.h"
@@ skipping 177 matching lines @@
 
     i::MaybeHandle<i::JSObject> object =
         result.val->Instantiate(isolate, ffi, memory);
 
     if (!object.is_null()) {
       args.GetReturnValue().Set(v8::Utils::ToLocal(object.ToHandleChecked()));
     }
   }
 
   if (result.val) delete result.val;
+  isolate->counters()->wasm_instantiate_peak_memory()->AddSample(
+      static_cast<int>(zone.allocation_size()));

[ahaas, 2016/04/11 08:03:08]

What exactly do you want to measure with this counter? When I first looked at
this code I thought this counter measures the peak memory consumption for the
whole module instantiation. However, the zone you measure is only used to decode
a wasm module, and there are also other zones in use to instantiate a module.
For example, there exists a zone to construct the graph in
wasm-compiler.cc::CompileWasmFunction, and there exists a whole zone pool in
pipeline.cc::GenerateCodeForTesting to compile the graph.

[bradn, 2016/04/13 00:22:45]

Erg, yeah this one doesn't make much sense.
Ideally I might aggregate them, but more important to get some measurements in
before the branch.
Dropping this one.

 }
 
 
 void InstantiateModuleFromAsm(const v8::FunctionCallbackInfo<v8::Value>& args) {
   HandleScope scope(args.GetIsolate());
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
   ErrorThrower thrower(isolate, "WASM.instantiateModuleFromAsm()");
 
   if (!args[0]->IsString()) {
     thrower.Error("Asm module text should be a string");
@@ skipping 109 matching lines @@
     int unused_property_fields = in_object_properties - pre_allocated;
     Handle<Map> map = Map::CopyInitialMap(
         prev_map, instance_size, in_object_properties, unused_property_fields);
 
     context->set_wasm_function_map(*map);
   }
 }
 
 }  // namespace internal
 }  // namespace v8