[wasm] Fix logging for imports with names

Imports can also have associated names, and in fact we generate these
names for asm.js. Thus in logging, just append this name to the
generated signature.

R=jkummerow@chromium.org

Bug: chromium:1030103
Change-Id: I3969bcf8d1d17f4256b5a0643acdf8a24766f889
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1948705
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65321}

src/wasm/wasm-code-manager.cc

@@ -196,15 +196,23 @@ void WasmCode::LogCode(Isolate* isolate) const {
 
   std::unique_ptr<char[]> name_buffer;
   if (kind_ == kWasmToJsWrapper) {
-    DCHECK(name.empty());
     constexpr size_t kNameBufferLen = 128;
     constexpr size_t kNamePrefixLen = 11;
     name_buffer = std::make_unique<char[]>(kNameBufferLen);
     memcpy(name_buffer.get(), "wasm-to-js:", kNamePrefixLen);
-    Vector<char> sig_buf =
+    Vector<char> remaining_buf =
         VectorOf(name_buffer.get(), kNameBufferLen) + kNamePrefixLen;
     FunctionSig* sig = native_module()->module()->functions[index_].sig;
-    size_t name_len = kNamePrefixLen + PrintSignature(sig_buf, sig);
+    remaining_buf += PrintSignature(remaining_buf, sig);
+    // If the import has a name, also append that (separated by "-").
+    if (!name.empty() && remaining_buf.length() > 1) {
+      remaining_buf[0] = '-';
+      remaining_buf += 1;
+      size_t suffix_len = std::min(name.size(), remaining_buf.size());
+      memcpy(remaining_buf.begin(), name.begin(), suffix_len);
+      remaining_buf += suffix_len;
+    }
+    size_t name_len = remaining_buf.begin() - name_buffer.get();
     name = VectorOf(name_buffer.get(), name_len);
   } else if (name.empty()) {
     name = CStrVector("<wasm-unnamed>");

test/mjsunit/regress/wasm/regress-1030103.js

+// Copyright 2019 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.
+
+// Flags: --log-code
+
+(function(foo, foreign) {
+  'use asm';
+  var fn = foreign.fn;
+  function f() { }
+  return f;
+})(this, {fn: x => x});