Fuzzer: Remove --emit-js-shell logic and reuse fuzz_shell.js instead (#6310)

We had two JS files that could run a wasm file for fuzzing purposes:

* --emit-js-shell, which emitted a custom JS file that runs the wasm.
* scripts/fuzz_shell.js, which was a generic file that did the same.

Both of those load the wasm and then call the exports in order and print out
logging as it goes of their return values (if any), exceptions, etc. Then the
fuzzer compares that output to running the same wasm in another VM, etc. The
difference is that one was custom for the wasm file, and one was generic. Aside
from that they are similar and duplicated a bunch of code.

This PR improves things by removing 1 and using 2 in all places, that is, we
now use the generic file everywhere.

I believe we added 1 because we thought a generic file can't do all the
things we need, like know the order of exports and the types of return values,
but in practice there are ways to do those things: The exports are in fact
in the proper order (JS order of iteration is deterministic, thankfully), and
for the type we don't want to print type internals anyhow since that would
limit fuzzing --closed-world. We do need to be careful with types in JS (see
notes in the PR about the type of null) but it's not too bad. As for the types
of params, it's fine to pass in null for them all anyhow (null converts to a
number or a reference without error).

1 files changed, 0 insertions, 134 deletions

diff --git a/src/tools/js-wrapper.h b/src/tools/js-wrapper.h
deleted file mode 100644
index edee301ca..000000000
--- a/src/tools/js-wrapper.h
+++ /dev/null
@@ -1,134 +0,0 @@
-/*
- * Copyright 2017 WebAssembly Community Group participants
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-//
-// Emit a JavaScript wrapper to run a wasm module with some test
-// values, useful for fuzzing.
-//
-
-#include "wasm-type.h"
-#include "wasm.h"
-#include <string>
-
-namespace wasm {
-
-inline std::string generateJSWrapper(Module& wasm) {
-  std::string ret;
-  ret += "if (typeof console === 'undefined') {\n"
-         "  console = { log: print };\n"
-         "}\n"
-         "var tempRet0;\n"
-         "var binary;\n"
-         "if (typeof process === 'object' && typeof require === 'function' /* "
-         "node.js detection */) {\n"
-         "  var args = process.argv.slice(2);\n"
-         "  binary = require('fs').readFileSync(args[0]);\n"
-         "  if (!binary.buffer) binary = new Uint8Array(binary);\n"
-         "} else {\n"
-         "  var args;\n"
-         "  if (typeof scriptArgs != 'undefined') {\n"
-         "    args = scriptArgs;\n"
-         "  } else if (typeof arguments != 'undefined') {\n"
-         "    args = arguments;\n"
-         "  }\n"
-         "  if (typeof readbuffer === 'function') {\n"
-         "    binary = new Uint8Array(readbuffer(args[0]));\n"
-         "  } else {\n"
-         "    binary = read(args[0], 'binary');\n"
-         "  }\n"
-         "}\n"
-         "function literal(x, type) {\n"
-         "  var ret = '';\n"
-         "  switch (type) {\n"
-         "    case 'i32': ret += (x | 0); break;\n"
-         "    case 'f32':\n"
-         "    case 'f64': {\n"
-         "      if (x == 0 && (1 / x) < 0) ret += '-';\n"
-         "      ret += Number(x).toString();\n"
-         "      break;\n"
-         "    }\n"
-         "    // For anything else, just print the type.\n"
-         "    default: ret += type; break;\n"
-         "  }\n"
-         "  return ret;\n"
-         "}\n"
-         "var instance = new WebAssembly.Instance(new "
-         "WebAssembly.Module(binary), {\n"
-         "  'fuzzing-support': {\n"
-         "    'log-i32': function(x)    { "
-         "console.log('[LoggingExternalInterface logging ' + literal(x, 'i32') "
-         "+ ']') },\n"
-         "    'log-i64': function(x, y) { "
-         "console.log('[LoggingExternalInterface logging ' + literal(x, 'i32') "
-         "+ ' ' + literal(y, 'i32') + ']') },\n" // legalization: two i32s
-         "    'log-f32': function(x)    { "
-         "console.log('[LoggingExternalInterface logging ' + literal(x, 'f64') "
-         "+ ']') },\n" // legalization: an f64
-         "    'log-f64': function(x)    { "
-         "console.log('[LoggingExternalInterface logging ' + literal(x, 'f64') "
-         "+ ']') },\n"
-         "  },\n"
-         "  'env': {\n"
-         "    'setTempRet0': function(x) { tempRet0 = x },\n"
-         "    'getTempRet0': function() { return tempRet0 },\n"
-         "  },\n"
-         "});\n";
-  for (auto& exp : wasm.exports) {
-    if (exp->kind != ExternalKind::Function) {
-      continue; // something exported other than a function
-    }
-    auto* func = wasm.getFunction(exp->value);
-    ret += "try {\n";
-    ret += std::string("  console.log('[fuzz-exec] calling ") +
-           exp->name.toString() + "');\n";
-    if (func->getResults() != Type::none) {
-      ret += std::string("  console.log('[fuzz-exec] note result: ") +
-             exp->name.toString() + " => ' + literal(";
-    } else {
-      ret += "  ";
-    }
-    ret += std::string("instance.exports.") + exp->name.toString() + "(";
-    bool first = true;
-    for (auto param : func->getParams()) {
-      // zeros in arguments TODO more?
-      if (first) {
-        first = false;
-      } else {
-        ret += ", ";
-      }
-      if (param.isRef()) {
-        ret += "null";
-      } else {
-        ret += "0";
-        if (param == Type::i64) {
-          ret += ", 0";
-        }
-      }
-    }
-    ret += ")";
-    if (func->getResults() != Type::none) {
-      ret += ", '" + func->getResults().toString() + "'))";
-      // TODO: getTempRet
-    }
-    ret += ";\n";
-    ret += "} catch (e) {\n";
-    ret += "  console.log('exception!' /* + e */);\n";
-    ret += "}\n";
-  }
-  return ret;
-}
-
-} // namespace wasm