[wasm] Adding metrics for Asm/Wasm.

src/compiler/wasm-compiler.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/compiler/wasm-compiler.h"
 
 #include "src/isolate-inl.h"
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/platform.h"
@@ skipping 2659 matching lines @@
                               module_name);
   }
   return code;
 }
 
 
 // Helper function to compile a single function.
 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 "
        << wasm::WasmFunctionName(&function, module_env) << std::endl;
     os << std::endl;
   }
 
   double decode_ms = 0;
   base::ElapsedTimer decode_timer;
   if (FLAG_trace_wasm_decode_time) {
@@ skipping 83 matching lines @@
   }
 
   if (FLAG_trace_wasm_decode_time) {
     double compile_ms = compile_timer.Elapsed().InMillisecondsF();
     PrintF(
         "wasm-compile ok: %d bytes, %0.3f ms decode, %d nodes, %0.3f ms "
         "compile\n",
         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;
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8