[wasm] Support asm.js modules with a single function.

src/asmjs/asm-wasm-builder.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/v8.h"
 
 // Required to get M_E etc. in MSVC.
 #if defined(_WIN32)
 #define _USE_MATH_DEFINES
 #endif
@@ skipping 533 matching lines @@
       }
       LocalType var_type = TypeOf(expr);
       DCHECK_NE(kAstStmt, var_type);
       if (var->IsContextSlot()) {
         current_function_builder_->EmitWithVarInt(
             kExprGetGlobal, LookupOrInsertGlobal(var, var_type));
       } else {
         current_function_builder_->EmitGetLocal(
             LookupOrInsertLocal(var, var_type));
       }
+    } else if (scope_ == kExportScope) {
+      Variable* var = expr->var();
+      DCHECK(var->is_function());
+      uint32_t index = LookupOrInsertFunction(var);
+      builder_->FunctionAt(index)->SetExported();
+      std::string raw_name = "__single_function__";

[Mircea Trofin, 2016/09/19 18:42:29]

could we have these centrally defined?

[bradn, 2016/09/19 20:30:38]

Done.

+      builder_->FunctionAt(index)->SetName(
+          reinterpret_cast<const char*>(raw_name.data()), raw_name.length());
     }
   }
 
   void VisitLiteral(Literal* expr) {
     Handle<Object> value = expr->value();
     if (!value->IsNumber() || (scope_ != kFuncScope && scope_ != kInitScope)) {
       return;
     }
     AsmType* type = typer_->TypeOf(expr);
     DCHECK_NE(type, AsmType::None());
@@ skipping 1224 matching lines @@
   AsmWasmBuilderImpl impl(isolate_, zone_, literal_, typer_);
   impl.Build();
   *foreign_args = impl.GetForeignArgs();
   ZoneBuffer* buffer = new (zone_) ZoneBuffer(zone_);
   impl.builder_->WriteTo(*buffer);
   return buffer;
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8