[wasm] Adding metrics for Asm/Wasm.

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index ff80f953eb1ffd9737fc5af809d5b89c394cb1e4..a293c68cfbb1d8692317271e61cfa14dbed01c10 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -2677,6 +2677,8 @@ Handle<Code> CompileWasmToJSWrapper(Isolate* isolate, wasm::ModuleEnv* module,
 Handle<Code> CompileWasmFunction(wasm::ErrorThrower& thrower, Isolate* isolate,
                                  wasm::ModuleEnv* module_env,
                                  const wasm::WasmFunction& function) {
+  HistogramTimerScope wasm_compile_function_time_scope(
+      isolate->counters()->wasm_compile_function_time());
   if (FLAG_trace_wasm_compiler) {
     OFStream os(stdout);
     os << "Compiling WASM function "
@@ -2780,6 +2782,8 @@ Handle<Code> CompileWasmFunction(wasm::ErrorThrower& thrower, Isolate* isolate,
         static_cast<int>(function.code_end_offset - function.code_start_offset),
         decode_ms, static_cast<int>(graph.NodeCount()), compile_ms);
   }
+  isolate->counters()->wasm_compile_function_peak_memory()->AddSample(

[Mircea Trofin, 2016/04/13 17:51:25]

I'm a bit concerned with the downcast here from size_t to int, given the value
represents allocated memory size.

[bradnelson, 2016/04/14 07:05:22]

Agreed, but as above, the static_casts for these functions are a common pattern
with these histograms.
Added a TODO.

+      static_cast<int>(zone.allocation_size()));
   return code;
 }