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

src/asmjs/asm-wasm-builder.cc

Index: src/asmjs/asm-wasm-builder.cc
diff --git a/src/asmjs/asm-wasm-builder.cc b/src/asmjs/asm-wasm-builder.cc
index 00e304bbcb76edd7b89d4408b720cd434c9b2161..ee2ac53483e3d0c0fd63f3e6c3410980d51cd5aa 100644
--- a/src/asmjs/asm-wasm-builder.cc
+++ b/src/asmjs/asm-wasm-builder.cc
@@ -551,6 +551,14 @@ class AsmWasmBuilderImpl final : public AstVisitor<AsmWasmBuilderImpl> {
         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());
     }
   }