[wasm][asm.js] Enable --validate-asm by default.

This directs all asm.js traffic via the Wasm backend.
Make asm.js console output less noisy.

R=titzer@chromium.org,aseemgarg@chromium.org
BUG=v8:4203

Review-Url: https://codereview.chromium.org/2624813002
Cr-Original-Original-Commit-Position: refs/heads/master@{#42194}
Committed: https://chromium.googlesource.com/v8/v8/+/946cc371ed4b34d1a9f5cc615b14c41b652562ad
Review-Url: https://codereview.chromium.org/2624813002
Cr-Original-Commit-Position: refs/heads/master@{#42244}
Committed: https://chromium.googlesource.com/v8/v8/+/3169fb94c98953f002908974a606b51a35178046
Review-Url: https://codereview.chromium.org/2624813002
Cr-Commit-Position: refs/heads/master@{#42300}

src/asmjs/asm-js.cc

@@ -212,15 +212,9 @@ MaybeHandle<FixedArray> AsmJs::CompileAsmViaWasm(CompilationInfo* info) {
   MessageLocation location(info->script(), info->literal()->position(),
                            info->literal()->position());
   char text[100];
-  int length;
-  if (FLAG_trace_asm_time) {
-    length =
-        base::OS::SNPrintF(text, arraysize(text),
-                           "success, asm->wasm: %0.3f ms, compile: %0.3f ms",
-                           asm_wasm_time, compile_time);
-  } else {
-    length = base::OS::SNPrintF(text, arraysize(text), "success");
-  }
+  int length = base::OS::SNPrintF(
+      text, arraysize(text), "success, asm->wasm: %0.3f ms, compile: %0.3f ms",
+      asm_wasm_time, compile_time);
   DCHECK_NE(-1, length);
   USE(length);
   Handle<String> stext(info->isolate()->factory()->InternalizeUtf8String(text));
@@ -228,7 +222,7 @@ MaybeHandle<FixedArray> AsmJs::CompileAsmViaWasm(CompilationInfo* info) {
       info->isolate(), MessageTemplate::kAsmJsCompiled, &location, stext,
       Handle<JSArray>::null());
   message->set_error_level(v8::Isolate::kMessageInfo);
-  if (!FLAG_suppress_asm_messages) {
+  if (!FLAG_suppress_asm_messages && FLAG_trace_asm_time) {
     MessageHandler::ReportMessage(info->isolate(), &location, message);
   }
 
@@ -327,13 +321,9 @@ MaybeHandle<Object> AsmJs::InstantiateAsmWasm(i::Isolate* isolate,
   }
   MessageLocation location(script, position, position);
   char text[50];
-  int length;
-  if (FLAG_trace_asm_time) {
-    length = base::OS::SNPrintF(text, arraysize(text), "success, %0.3f ms",
-                                instantiate_timer.Elapsed().InMillisecondsF());
-  } else {
-    length = base::OS::SNPrintF(text, arraysize(text), "success");
-  }
+  int length =
+      base::OS::SNPrintF(text, arraysize(text), "success, %0.3f ms",
+                         instantiate_timer.Elapsed().InMillisecondsF());
   DCHECK_NE(-1, length);
   USE(length);
   Handle<String> stext(isolate->factory()->InternalizeUtf8String(text));
@@ -341,7 +331,9 @@ MaybeHandle<Object> AsmJs::InstantiateAsmWasm(i::Isolate* isolate,
       isolate, MessageTemplate::kAsmJsInstantiated, &location, stext,
       Handle<JSArray>::null());
   message->set_error_level(v8::Isolate::kMessageInfo);
-  MessageHandler::ReportMessage(isolate, &location, message);
+  if (!FLAG_suppress_asm_messages && FLAG_trace_asm_time) {
+    MessageHandler::ReportMessage(isolate, &location, message);
+  }
 
   return module_object;
 }

src/flag-definitions.h

@@ -517,7 +517,7 @@ DEFINE_BOOL(wasm_break_on_decoder_error, false,
 DEFINE_BOOL(wasm_loop_assignment_analysis, true,
             "perform loop assignment analysis for WASM")
 
-DEFINE_BOOL(validate_asm, false, "validate asm.js modules before compiling")
+DEFINE_BOOL(validate_asm, true, "validate asm.js modules before compiling")
 DEFINE_IMPLICATION(ignition_staging, validate_asm)
 DEFINE_BOOL(suppress_asm_messages, false,
             "don't emit asm.js related messages (for golden file testing)")