Remove --fuzz-binary and simplify round trip (#2799)

Since the --roundtrip pass is more general than --fuzz-binary anyways. Also reimplements `ModuleUtils::clearModule` to use the module destructor and placement new to ensure that no members are missed.

3 files changed, 20 insertions, 75 deletions

diff --git a/src/ir/module-utils.h b/src/ir/module-utils.h
index e589f5052..ab23649f7 100644
--- a/src/ir/module-utils.h
+++ b/src/ir/module-utils.h
@@ -99,17 +99,8 @@ inline void copyModule(const Module& in, Module& out) {
 }
 
 inline void clearModule(Module& wasm) {
-  wasm.exports.clear();
-  wasm.functions.clear();
-  wasm.globals.clear();
-  wasm.events.clear();
-  wasm.table.clear();
-  wasm.memory.clear();
-  wasm.start = Name();
-  wasm.userSections.clear();
-  wasm.debugInfoFileNames.clear();
-  wasm.updateMaps();
-  wasm.allocator.clear();
+  wasm.~Module();
+  new (&wasm) Module;
 }
 
 // Renaming
diff --git a/src/passes/RoundTrip.cpp b/src/passes/RoundTrip.cpp
index 5410ad87b..754881fe4 100644
--- a/src/passes/RoundTrip.cpp
+++ b/src/passes/RoundTrip.cpp
@@ -20,17 +20,9 @@
 // parameter.
 //
 
-#ifdef _WIN32
-#include <io.h>
-#endif
-
-#include <cstdlib>
-#include <vector>
-
 #include "ir/module-utils.h"
 #include "pass.h"
-#include "support/file.h"
-#include "wasm-io.h"
+#include "wasm-binary.h"
 #include "wasm.h"
 
 using namespace std;
@@ -39,28 +31,19 @@ namespace wasm {
 
 struct RoundTrip : public Pass {
   void run(PassRunner* runner, Module* module) override {
-    std::string templateName = "byn_round_trip_XXXXXX";
-    std::vector<char> buffer(templateName.begin(), templateName.end());
-    buffer.push_back(0);
-#ifndef _WIN32
-    auto fd = mkstemp(buffer.data());
-    WASM_UNUSED(fd);
-    std::string tempName(buffer.begin(), buffer.end());
-#else
-    std::string tempName = _mktemp(buffer.data());
-#endif
-    // Write
-    ModuleWriter writer;
-    writer.setBinary(true);
-    writer.setDebugInfo(runner->options.debugInfo);
-    writer.write(*module, tempName);
-    // Read
+    BufferWithRandomAccess buffer;
+    // Save features, which would not otherwise make it through a round trip if
+    // the target features section has been stripped.
+    auto features = module->features;
+    // Write, clear, and read the module
+    WasmBinaryWriter(module, buffer).write();
     ModuleUtils::clearModule(*module);
-    ModuleReader reader;
-    reader.setDWARF(runner->options.debugInfo);
-    reader.read(tempName, *module);
-    // Clean up
-    std::remove(tempName.c_str());
+    auto input = buffer.getAsChars();
+    WasmBinaryBuilder parser(*module, input);
+    parser.setDWARF(runner->options.debugInfo);
+    parser.read();
+    // Reapply features
+    module->features = features;
   }
 };
 
diff --git a/src/tools/wasm-opt.cpp b/src/tools/wasm-opt.cpp
index 6fd3b7c8d..a215aca32 100644
--- a/src/tools/wasm-opt.cpp
+++ b/src/tools/wasm-opt.cpp
@@ -79,7 +79,6 @@ int main(int argc, const char* argv[]) {
   bool converge = false;
   bool fuzzExecBefore = false;
   bool fuzzExecAfter = false;
-  bool fuzzBinary = false;
   std::string extraFuzzCommand;
   bool translateToFuzz = false;
   bool fuzzPasses = false;
@@ -127,12 +126,6 @@ int main(int argc, const char* argv[]) {
          [&](Options* o, const std::string& arguments) {
            fuzzExecBefore = fuzzExecAfter = true;
          })
-    .add("--fuzz-binary",
-         "-fb",
-         "Convert to binary and back after optimizations and before fuzz-exec, "
-         "helping fuzzing find binary format bugs",
-         Options::Arguments::Zero,
-         [&](Options* o, const std::string& arguments) { fuzzBinary = true; })
     .add("--extra-fuzz-command",
          "-efc",
          "An extra command to run on the output before and after optimizing. "
@@ -328,28 +321,6 @@ int main(int argc, const char* argv[]) {
     std::cout << "[extra-fuzz-command first output:]\n" << firstOutput << '\n';
   }
 
-  Module* curr = &wasm;
-  Module other;
-
-  if (fuzzExecAfter && fuzzBinary) {
-    BufferWithRandomAccess buffer;
-    // write the binary
-    WasmBinaryWriter writer(&wasm, buffer);
-    writer.write();
-    // read the binary
-    auto input = buffer.getAsChars();
-    WasmBinaryBuilder parser(other, input);
-    parser.read();
-    options.applyFeatures(other);
-    if (options.passOptions.validate) {
-      bool valid = WasmValidator().validate(other);
-      if (!valid) {
-        Fatal() << "fuzz-binary must always generate a valid module";
-      }
-    }
-    curr = &other;
-  }
-
   if (!options.runningPasses()) {
     if (!options.quiet) {
       std::cerr << "warning: no passes specified, not doing any work\n";
@@ -357,9 +328,9 @@ int main(int argc, const char* argv[]) {
   } else {
     BYN_TRACE("running passes...\n");
     auto runPasses = [&]() {
-      options.runPasses(*curr);
+      options.runPasses(wasm);
       if (options.passOptions.validate) {
-        bool valid = WasmValidator().validate(*curr);
+        bool valid = WasmValidator().validate(wasm);
         if (!valid) {
           exitOnInvalidWasm("error after opts");
         }
@@ -371,7 +342,7 @@ int main(int argc, const char* argv[]) {
       // size no longer decreasing.
       auto getSize = [&]() {
         BufferWithRandomAccess buffer;
-        WasmBinaryWriter writer(curr, buffer);
+        WasmBinaryWriter writer(&wasm, buffer);
         writer.write();
         return buffer.size();
       };
@@ -389,7 +360,7 @@ int main(int argc, const char* argv[]) {
   }
 
   if (fuzzExecAfter) {
-    results.check(*curr);
+    results.check(wasm);
   }
 
   if (options.extra.count("output") == 0) {
@@ -407,7 +378,7 @@ int main(int argc, const char* argv[]) {
     writer.setSourceMapFilename(outputSourceMapFilename);
     writer.setSourceMapUrl(outputSourceMapUrl);
   }
-  writer.write(*curr, options.extra["output"]);
+  writer.write(wasm, options.extra["output"]);
 
   if (extraFuzzCommand.size() > 0) {
     auto secondOutput = runCommand(extraFuzzCommand);