fix BINARYEN_PASS_DEBUG option (#908)

* fix BINARYEN_PASS_DEBUG option

 * Add isNested property to passRunner

6 files changed, 25 insertions, 5 deletions

diff --git a/src/pass.h b/src/pass.h
index 1fcd88e0c..faf674c49 100644
--- a/src/pass.h
+++ b/src/pass.h
@@ -123,6 +123,16 @@ struct PassRunner {
 
   ~PassRunner();
 
+  // When running a pass runner within another pass runner, this
+  // flag should be set. This influences how pass debugging works,
+  // and may influence other things in the future too.
+  void setIsNested(bool nested) {
+    isNested = nested;
+  }
+
+protected:
+  bool isNested = false;
+
 private:
   void doAdd(Pass* pass);
 
diff --git a/src/passes/DuplicateFunctionElimination.cpp b/src/passes/DuplicateFunctionElimination.cpp
index 05eaadfe5..5d55c7318 100644
--- a/src/passes/DuplicateFunctionElimination.cpp
+++ b/src/passes/DuplicateFunctionElimination.cpp
@@ -89,6 +89,7 @@ struct DuplicateFunctionElimination : public Pass {
         hashes[func.get()] = 0; // ensure an entry for each function - we must not modify the map shape in parallel, just the values
       }
       PassRunner hasherRunner(module);
+      hasherRunner.setIsNested(true);
       hasherRunner.add<FunctionHasher>(&hashes);
       hasherRunner.run();
       // Find hash-equal groups
@@ -131,6 +132,7 @@ struct DuplicateFunctionElimination : public Pass {
         module->updateMaps();
         // replace direct calls
         PassRunner replacerRunner(module);
+        replacerRunner.setIsNested(true);
         replacerRunner.add<FunctionReplacer>(&replacements);
         replacerRunner.run();
         // replace in table
diff --git a/src/passes/Inlining.cpp b/src/passes/Inlining.cpp
index 943bbc500..c352a704a 100644
--- a/src/passes/Inlining.cpp
+++ b/src/passes/Inlining.cpp
@@ -145,6 +145,7 @@ struct Inlining : public Pass {
     }
     {
       PassRunner runner(module);
+      runner.setIsNested(true);
       runner.add<FunctionUseCounter>(&uses);
       runner.run();
     }
@@ -172,6 +173,7 @@ struct Inlining : public Pass {
     // find and plan inlinings
     {
       PassRunner runner(module);
+      runner.setIsNested(true);
       runner.add<Planner>(&state);
       runner.run();
     }
diff --git a/src/passes/LegalizeJSInterface.cpp b/src/passes/LegalizeJSInterface.cpp
index f2ecb479f..4bb25361f 100644
--- a/src/passes/LegalizeJSInterface.cpp
+++ b/src/passes/LegalizeJSInterface.cpp
@@ -94,6 +94,7 @@ struct LegalizeJSInterface : public Pass {
       };
 
       PassRunner passRunner(module);
+      passRunner.setIsNested(true);
       passRunner.add<FixImports>(&illegalToLegal);
       passRunner.run();
     }
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index df98590c5..081164d90 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -142,7 +142,12 @@ void PassRunner::addDefaultGlobalOptimizationPasses() {
 }
 
 void PassRunner::run() {
-  if (options.debug) {
+  // BINARYEN_PASS_DEBUG is a convenient commandline way to log out the toplevel passes, their times,
+  //                     and validate between each pass.
+  //                     (we don't recurse pass debug into sub-passes, as it doesn't help anyhow and
+  //                     also is bad for e.g. printing which is a pass)
+  static const int passDebug = getenv("BINARYEN_PASS_DEBUG") ? atoi(getenv("BINARYEN_PASS_DEBUG")) : 0;
+  if (!isNested && (options.debug || passDebug)) {
     // for debug logging purposes, run each pass in full before running the other
     auto totalTime = std::chrono::duration<double>(0);
     size_t padding = 0;
@@ -150,11 +155,10 @@ void PassRunner::run() {
     for (auto pass : passes) {
       padding = std::max(padding, pass->name.size());
     }
-    bool passDebug = getenv("BINARYEN_PASS_DEBUG") && getenv("BINARYEN_PASS_DEBUG")[0] != '0';
     for (auto* pass : passes) {
       // ignoring the time, save a printout of the module before, in case this pass breaks it, so we can print the before and after
       std::stringstream moduleBefore;
-      if (passDebug) {
+      if (passDebug == 2) {
         WasmPrinter::printModule(wasm, moduleBefore);
       }
       // prepare to run
@@ -178,10 +182,10 @@ void PassRunner::run() {
       // validate, ignoring the time
       std::cerr << "[PassRunner]   (validating)\n";
       if (!WasmValidator().validate(*wasm, false, options.validateGlobally)) {
-        if (passDebug) {
+        if (passDebug >= 2) {
           std::cerr << "Last pass (" << pass->name << ") broke validation. Here is the module before: \n" << moduleBefore.str() << "\n";
         } else {
-          std::cerr << "Last pass (" << pass->name << ") broke validation. Run with BINARYEN_PASS_DEBUG=1 in the env to see the earlier state\n";
+          std::cerr << "Last pass (" << pass->name << ") broke validation. Run with BINARYEN_PASS_DEBUG=2 in the env to see the earlier state (FIXME: this is broken, need to prevent recursion of the print pass\n";
         }
         abort();
       }
diff --git a/src/wasm-printing.h b/src/wasm-printing.h
index 830f2dda2..a445866d8 100644
--- a/src/wasm-printing.h
+++ b/src/wasm-printing.h
@@ -27,6 +27,7 @@ namespace wasm {
 struct WasmPrinter {
   static std::ostream& printModule(Module* module, std::ostream& o) {
     PassRunner passRunner(module);
+    passRunner.setIsNested(true);
     passRunner.add<Printer>(&o);
     passRunner.run();
     return o;