Refactor printing code so that printing Expressions always works (#3450)

This avoids needing to add include wasm-printing if a file doesn't already have it.
To achieve that, add the std::ostream hooks in wasm.h, and also use them
when possible, removing the need for the special WasmPrinter object.

Also stop printing in "full" (print types on each line) in error messages by default. The
user can still get that, as always, using BINARYEN_PRINT_FULL=1 in the env.

28 files changed, 105 insertions, 172 deletions

diff --git a/src/binaryen-c.cpp b/src/binaryen-c.cpp
index 7365a3863..29724ec10 100644
--- a/src/binaryen-c.cpp
+++ b/src/binaryen-c.cpp
@@ -29,7 +29,6 @@
 #include "wasm-binary.h"
 #include "wasm-builder.h"
 #include "wasm-interpreter.h"
-#include "wasm-printing.h"
 #include "wasm-s-parser.h"
 #include "wasm-validator.h"
 #include "wasm.h"
@@ -1276,8 +1275,7 @@ void BinaryenExpressionSetType(BinaryenExpressionRef expr, BinaryenType type) {
   ((Expression*)expr)->type = Type(type);
 }
 void BinaryenExpressionPrint(BinaryenExpressionRef expr) {
-  WasmPrinter::printExpression((Expression*)expr, std::cout);
-  std::cout << '\n';
+  std::cout << *(Expression*)expr << '\n';
 }
 void BinaryenExpressionFinalize(BinaryenExpressionRef expr) {
   ReFinalizeNode().visit((Expression*)expr);
@@ -3382,7 +3380,7 @@ BinaryenModuleRef BinaryenModuleParse(const char* text) {
 }
 
 void BinaryenModulePrint(BinaryenModuleRef module) {
-  WasmPrinter::printModule((Module*)module);
+  std::cout << *(Module*)module;
 }
 
 void BinaryenModulePrintAsmjs(BinaryenModuleRef module) {
@@ -3546,7 +3544,7 @@ size_t BinaryenModuleWriteText(BinaryenModuleRef module,
   // use a stringstream as an std::ostream. Extract the std::string
   // representation, and then store in the output.
   std::stringstream ss;
-  WasmPrinter::printModule((Module*)module, ss);
+  ss << *(Module*)module;
 
   const auto temp = ss.str();
   const auto ctemp = temp.c_str();
@@ -3591,7 +3589,7 @@ BinaryenModuleAllocateAndWrite(BinaryenModuleRef module,
 
 char* BinaryenModuleAllocateAndWriteText(BinaryenModuleRef module) {
   std::stringstream ss;
-  WasmPrinter::printModule((Module*)module, ss);
+  ss << *(Module*)module;
 
   const std::string out = ss.str();
   const int len = out.length() + 1;
diff --git a/src/dataflow/utils.h b/src/dataflow/utils.h
index 436ccc4d8..02625212e 100644
--- a/src/dataflow/utils.h
+++ b/src/dataflow/utils.h
@@ -26,7 +26,6 @@
 #define wasm_dataflow_utils_h
 
 #include "dataflow/node.h"
-#include "wasm-printing.h"
 #include "wasm.h"
 
 namespace wasm {
@@ -47,7 +46,7 @@ inline std::ostream& dump(Node* node, std::ostream& o, size_t indent = 0) {
       break;
     case Node::Type::Expr: {
       o << "expr ";
-      WasmPrinter::printExpression(node->expr, o, true);
+      o << *node->expr << '\n';
       break;
     }
     case Node::Type::Phi:
diff --git a/src/ir/LocalGraph.cpp b/src/ir/LocalGraph.cpp
index dd7046351..bf1f7e576 100644
--- a/src/ir/LocalGraph.cpp
+++ b/src/ir/LocalGraph.cpp
@@ -20,7 +20,6 @@
 #include <ir/find_all.h>
 #include <ir/local-graph.h>
 #include <wasm-builder.h>
-#include <wasm-printing.h>
 
 namespace wasm {
 
diff --git a/src/parsing.h b/src/parsing.h
index 680f2f5cc..22d45de07 100644
--- a/src/parsing.h
+++ b/src/parsing.h
@@ -26,7 +26,7 @@
 #include "shared-constants.h"
 #include "support/colors.h"
 #include "support/utilities.h"
-#include "wasm-printing.h"
+#include "wasm-traversal.h"
 #include "wasm.h"
 
 namespace wasm {
diff --git a/src/passes/PostAssemblyScript.cpp b/src/passes/PostAssemblyScript.cpp
index eeb077ce9..aa9c5cc40 100644
--- a/src/passes/PostAssemblyScript.cpp
+++ b/src/passes/PostAssemblyScript.cpp
@@ -28,7 +28,6 @@
 #include <unordered_map>
 #include <unordered_set>
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
-#include "wasm-printing.h"
 #include <iostream>
 #endif
 
@@ -468,14 +467,14 @@ struct OptimizeARC : public WalkerPass<PostWalker<OptimizeARC>> {
             if (allBalanced) {
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
               std::cerr << "  eliminating ";
-              WasmPrinter::printExpression(retain, std::cerr, true);
+              std::cerr << *retain << '\n';
               std::cerr << " reaching\n";
 #endif
               redundantRetains.insert(retainLocation);
               for (auto** getLocation : releaseLocations) {
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
                 std::cerr << "    ";
-                WasmPrinter::printExpression(*getLocation, std::cerr, true);
+                std::cerr << **getLocation << '\n';
                 std::cerr << "\n";
 #endif
                 redundantReleases.insert(getLocation);
@@ -483,28 +482,28 @@ struct OptimizeARC : public WalkerPass<PostWalker<OptimizeARC>> {
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
             } else {
               std::cerr << "  cannot eliminate ";
-              WasmPrinter::printExpression(retain, std::cerr, true);
+              std::cerr << *retain << '\n';
               std::cerr << " - unbalanced\n";
 #endif
             }
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
           } else {
             std::cerr << "  cannot eliminate ";
-            WasmPrinter::printExpression(retain, std::cerr, true);
+            std::cerr << *retain << '\n';
             std::cerr << " - zero releases\n";
 #endif
           }
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
         } else {
           std::cerr << "  cannot eliminate ";
-          WasmPrinter::printExpression(retain, std::cerr, true);
+          std::cerr << *retain << '\n';
           std::cerr << " - retains allocation\n";
 #endif
         }
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
       } else {
         std::cerr << "  cannot eliminate ";
-        WasmPrinter::printExpression(retain, std::cerr, true);
+        std::cerr << *retain << '\n';
         std::cerr << " - reaches return\n";
 #endif
       }
@@ -560,7 +559,7 @@ struct FinalizeARC : public WalkerPass<PostWalker<FinalizeARC>> {
               // __release(__retain(__alloc(...))) - unnecessary allocation
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
               std::cerr << "  finalizing ";
-              WasmPrinter::printExpression(curr, std::cerr, true);
+              std::cerr << *curr << '\n';
               std::cerr << " - unnecessary allocation\n";
 #endif
               Builder builder(*getModule());
@@ -574,7 +573,7 @@ struct FinalizeARC : public WalkerPass<PostWalker<FinalizeARC>> {
           // __release(__retain(...)) - unnecessary pair
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
           std::cerr << "  finalizing ";
-          WasmPrinter::printExpression(curr, std::cerr, true);
+          std::cerr << *curr << '\n';
           std::cerr << " - unnecessary pair\n";
 #endif
           Builder builder(*getModule());
@@ -586,7 +585,7 @@ struct FinalizeARC : public WalkerPass<PostWalker<FinalizeARC>> {
         // __release(42) - unnecessary static release
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
         std::cerr << "  finalizing ";
-        WasmPrinter::printExpression(curr, std::cerr, true);
+        std::cerr << *curr << '\n';
         std::cerr << " - static release\n";
 #endif
         Builder builder(*getModule());
@@ -598,7 +597,7 @@ struct FinalizeARC : public WalkerPass<PostWalker<FinalizeARC>> {
         // __retain(42) - unnecessary static retain
 #ifdef POST_ASSEMBLYSCRIPT_DEBUG
         std::cerr << "  finalizing ";
-        WasmPrinter::printExpression(curr, std::cerr, true);
+        std::cerr << *curr << '\n';
         std::cerr << " - static retain\n";
 #endif
         replaceCurrent(retainedConst);
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index b61a72720..c0e940d04 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -21,12 +21,22 @@
 #include <ir/module-utils.h>
 #include <pass.h>
 #include <pretty_printing.h>
-#include <wasm-printing.h>
 #include <wasm-stack.h>
 #include <wasm.h>
 
 namespace wasm {
 
+static std::ostream& printExpression(Expression* expression,
+                                     std::ostream& o,
+                                     bool minify = false,
+                                     bool full = false);
+
+static std::ostream&
+printStackInst(StackInst* inst, std::ostream& o, Function* func = nullptr);
+
+static std::ostream&
+printStackIR(StackIR* ir, std::ostream& o, Function* func = nullptr);
+
 namespace {
 
 bool isFullForced() {
@@ -1814,9 +1824,9 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
 
   bool full = false; // whether to not elide nodes in output when possible
                      // (like implicit blocks) and to emit types
-  bool printStackIR = false; // whether to print stack IR if it is present
-                             // (if false, and Stack IR is there, we just
-                             // note it exists)
+  bool stackIR = false; // whether to print stack IR if it is present
+                        // (if false, and Stack IR is there, we just
+                        // note it exists)
 
   Module* currModule = nullptr;
   Function* currFunction = nullptr;
@@ -1876,7 +1886,7 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
 
   void setFull(bool full_) { full = full_; }
 
-  void setPrintStackIR(bool printStackIR_) { printStackIR = printStackIR_; }
+  void setStackIR(bool stackIR_) { stackIR = stackIR_; }
 
   void setDebugInfo(bool debugInfo_) { debugInfo = debugInfo_; }
 
@@ -2680,7 +2690,7 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     o << '(';
     printMajor(o, "func ");
     printName(curr->name, o);
-    if (!printStackIR && curr->stackIR && !minify) {
+    if (!stackIR && curr->stackIR && !minify) {
       o << " (; has Stack IR ;)";
     }
     if (curr->sig.params.size() > 0) {
@@ -2708,7 +2718,7 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
       o << maybeNewLine;
     }
     // Print the body.
-    if (!printStackIR || !curr->stackIR) {
+    if (!stackIR || !curr->stackIR) {
       // It is ok to emit a block here, as a function can directly contain a
       // list, even if our ast avoids that for simplicity. We can just do that
       // optimization here..
@@ -2723,7 +2733,7 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
       }
     } else {
       // Print the stack IR.
-      WasmPrinter::printStackIR(curr->stackIR.get(), o, curr);
+      printStackIR(curr->stackIR.get(), o, curr);
     }
     if (currFunction->epilogLocation.size() &&
         lastPrintedLocation != *currFunction->epilogLocation.begin()) {
@@ -3061,29 +3071,17 @@ public:
   void run(PassRunner* runner, Module* module) override {
     PrintSExpression print(o);
     print.setDebugInfo(runner->options.debugInfo);
-    print.setPrintStackIR(true);
+    print.setStackIR(true);
     print.visitModule(module);
   }
 };
 
 Pass* createPrintStackIRPass() { return new PrintStackIR(); }
 
-// Print individual expressions
-
-std::ostream& WasmPrinter::printModule(Module* module, std::ostream& o) {
-  PassRunner runner(module);
-  Printer(&o).run(&runner, module);
-  return o;
-}
-
-std::ostream& WasmPrinter::printModule(Module* module) {
-  return printModule(module, std::cout);
-}
-
-std::ostream& WasmPrinter::printExpression(Expression* expression,
-                                           std::ostream& o,
-                                           bool minify,
-                                           bool full) {
+static std::ostream& printExpression(Expression* expression,
+                                     std::ostream& o,
+                                     bool minify,
+                                     bool full) {
   if (!expression) {
     o << "(null expression)";
     return o;
@@ -3098,8 +3096,8 @@ std::ostream& WasmPrinter::printExpression(Expression* expression,
   return o;
 }
 
-std::ostream&
-WasmPrinter::printStackInst(StackInst* inst, std::ostream& o, Function* func) {
+static std::ostream&
+printStackInst(StackInst* inst, std::ostream& o, Function* func) {
   switch (inst->op) {
     case StackInst::Basic: {
       PrintExpressionContents(func, o).visit(inst->origin);
@@ -3133,8 +3131,8 @@ WasmPrinter::printStackInst(StackInst* inst, std::ostream& o, Function* func) {
   return o;
 }
 
-std::ostream&
-WasmPrinter::printStackIR(StackIR* ir, std::ostream& o, Function* func) {
+static std::ostream&
+printStackIR(StackIR* ir, std::ostream& o, Function* func) {
   size_t indent = func ? 2 : 0;
   auto doIndent = [&indent, &o]() {
     for (size_t j = 0; j < indent; j++) {
@@ -3198,3 +3196,29 @@ WasmPrinter::printStackIR(StackIR* ir, std::ostream& o, Function* func) {
 }
 
 } // namespace wasm
+
+namespace std {
+
+std::ostream& operator<<(std::ostream& o, wasm::Module& module) {
+  wasm::PassRunner runner(&module);
+  wasm::Printer(&o).run(&runner, &module);
+  return o;
+}
+
+std::ostream& operator<<(std::ostream& o, wasm::Expression& expression) {
+  return wasm::printExpression(&expression, o);
+}
+
+std::ostream& operator<<(std::ostream& o, wasm::Expression* expression) {
+  return wasm::printExpression(expression, o);
+}
+
+std::ostream& operator<<(std::ostream& o, wasm::StackInst& inst) {
+  return wasm::printStackInst(&inst, o);
+}
+
+std::ostream& operator<<(std::ostream& o, wasm::StackIR& ir) {
+  return wasm::printStackIR(&ir, o);
+}
+
+} // namespace std
diff --git a/src/passes/ReReloop.cpp b/src/passes/ReReloop.cpp
index 30cd55f44..374a54bb8 100644
--- a/src/passes/ReReloop.cpp
+++ b/src/passes/ReReloop.cpp
@@ -31,10 +31,6 @@
 #include "wasm-traversal.h"
 #include "wasm.h"
 
-#ifdef RERELOOP_DEBUG
-#include <wasm-printing.h>
-#endif
-
 namespace wasm {
 
 struct ReReloop final : public Pass {
diff --git a/src/passes/Souperify.cpp b/src/passes/Souperify.cpp
index fb0a9d7b9..90fd64777 100644
--- a/src/passes/Souperify.cpp
+++ b/src/passes/Souperify.cpp
@@ -464,8 +464,7 @@ struct Printer {
       case Node::Type::Expr: {
         if (debug()) {
           std::cout << "; ";
-          WasmPrinter::printExpression(node->expr, std::cout, true);
-          std::cout << '\n';
+          std::cout << *node->expr << '\n';
         }
         std::cout << "%" << indexing[node] << " = ";
         printExpression(node);
diff --git a/src/passes/TrapMode.cpp b/src/passes/TrapMode.cpp
index 528357d4a..9c9dee9ca 100644
--- a/src/passes/TrapMode.cpp
+++ b/src/passes/TrapMode.cpp
@@ -26,7 +26,6 @@
 #include "pass.h"
 #include "support/name.h"
 #include "wasm-builder.h"
-#include "wasm-printing.h"
 #include "wasm-type.h"
 #include "wasm.h"
 
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index 58083c43b..64e48680e 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -561,7 +561,7 @@ void PassRunner::run() {
       // pass breaks it, so we can print the before and after
       std::stringstream moduleBefore;
       if (passDebug == 2 && !isNested) {
-        WasmPrinter::printModule(wasm, moduleBefore);
+        moduleBefore << *wasm << '\n';
       }
       // prepare to run
       std::cerr << "[PassRunner]   running pass: " << pass->name << "... ";
@@ -584,7 +584,7 @@ void PassRunner::run() {
         // validate, ignoring the time
         std::cerr << "[PassRunner]   (validating)\n";
         if (!WasmValidator().validate(*wasm, validationFlags)) {
-          WasmPrinter::printModule(wasm);
+          std::cout << *wasm << '\n';
           if (passDebug >= 2) {
             Fatal() << "Last pass (" << pass->name
                     << ") broke validation. Here is the module before: \n"
@@ -606,7 +606,7 @@ void PassRunner::run() {
     if (options.validate && !isNested) {
       std::cerr << "[PassRunner] (final validation)\n";
       if (!WasmValidator().validate(*wasm, validationFlags)) {
-        WasmPrinter::printModule(wasm);
+        std::cout << *wasm << '\n';
         Fatal() << "final module does not validate\n";
       }
     }
diff --git a/src/tools/wasm-ctor-eval.cpp b/src/tools/wasm-ctor-eval.cpp
index 941e7961d..9e78cfb7a 100644
--- a/src/tools/wasm-ctor-eval.cpp
+++ b/src/tools/wasm-ctor-eval.cpp
@@ -466,7 +466,7 @@ int main(int argc, const char* argv[]) {
   options.applyFeatures(wasm);
 
   if (!WasmValidator().validate(wasm)) {
-    WasmPrinter::printModule(&wasm);
+    std::cout << wasm << '\n';
     Fatal() << "error in validating input";
   }
 
diff --git a/src/tools/wasm-dis.cpp b/src/tools/wasm-dis.cpp
index 89925b9cc..8220e96cd 100644
--- a/src/tools/wasm-dis.cpp
+++ b/src/tools/wasm-dis.cpp
@@ -22,7 +22,6 @@
 #include "support/command-line.h"
 #include "support/file.h"
 #include "wasm-io.h"
-#include "wasm-printing.h"
 
 using namespace cashew;
 using namespace wasm;
@@ -76,8 +75,7 @@ int main(int argc, const char* argv[]) {
     std::cerr << "Printing..." << std::endl;
   }
   Output output(options.extra["output"], Flags::Text);
-  WasmPrinter::printModule(&wasm, output.getStream());
-  output << '\n';
+  output.getStream() << wasm << '\n';
 
   if (options.debug) {
     std::cerr << "Done." << std::endl;
diff --git a/src/tools/wasm-emscripten-finalize.cpp b/src/tools/wasm-emscripten-finalize.cpp
index 844dfbb60..d12594274 100644
--- a/src/tools/wasm-emscripten-finalize.cpp
+++ b/src/tools/wasm-emscripten-finalize.cpp
@@ -30,7 +30,6 @@
 #include "wasm-binary.h"
 #include "wasm-emscripten.h"
 #include "wasm-io.h"
-#include "wasm-printing.h"
 #include "wasm-validator.h"
 
 #define DEBUG_TYPE "emscripten"
@@ -222,8 +221,7 @@ int main(int argc, const char* argv[]) {
   options.applyFeatures(wasm);
 
   BYN_TRACE_WITH_TYPE("emscripten-dump", "Module before:\n");
-  BYN_DEBUG_WITH_TYPE("emscripten-dump",
-                      WasmPrinter::printModule(&wasm, std::cerr));
+  BYN_DEBUG_WITH_TYPE("emscripten-dump", std::cerr << &wasm);
 
   EmscriptenGlueGenerator generator(wasm);
   generator.standalone = standaloneWasm;
@@ -315,8 +313,7 @@ int main(int argc, const char* argv[]) {
   }
 
   BYN_TRACE_WITH_TYPE("emscripten-dump", "Module after:\n");
-  BYN_DEBUG_WITH_TYPE("emscripten-dump",
-                      WasmPrinter::printModule(&wasm, std::cerr));
+  BYN_DEBUG_WITH_TYPE("emscripten-dump", std::cerr << wasm << '\n');
 
   // Write the modified wasm if the user asked us to, either by specifying an
   // output file, or requesting text output (which goes to stdout by default).
diff --git a/src/tools/wasm-metadce.cpp b/src/tools/wasm-metadce.cpp
index 3b889b984..87bb293b6 100644
--- a/src/tools/wasm-metadce.cpp
+++ b/src/tools/wasm-metadce.cpp
@@ -511,7 +511,7 @@ int main(int argc, const char* argv[]) {
 
   if (options.passOptions.validate) {
     if (!WasmValidator().validate(wasm)) {
-      WasmPrinter::printModule(&wasm);
+      std::cout << wasm << '\n';
       Fatal() << "error in validating input";
     }
   }
diff --git a/src/tools/wasm-opt.cpp b/src/tools/wasm-opt.cpp
index 56a26ccfb..8884619fe 100644
--- a/src/tools/wasm-opt.cpp
+++ b/src/tools/wasm-opt.cpp
@@ -34,7 +34,6 @@
 #include "wasm-binary.h"
 #include "wasm-interpreter.h"
 #include "wasm-io.h"
-#include "wasm-printing.h"
 #include "wasm-s-parser.h"
 #include "wasm-validator.h"
 #include "wasm2c-wrapper.h"
@@ -227,7 +226,7 @@ int main(int argc, const char* argv[]) {
     // to print would not be reached).
     if (std::find(options.passes.begin(), options.passes.end(), "print") !=
         options.passes.end()) {
-      WasmPrinter::printModule(&wasm);
+      std::cout << wasm << '\n';
     }
     Fatal() << message;
   };
@@ -279,7 +278,7 @@ int main(int argc, const char* argv[]) {
     reader.build();
     if (options.passOptions.validate) {
       if (!WasmValidator().validate(wasm)) {
-        WasmPrinter::printModule(&wasm);
+        std::cout << wasm << '\n';
         Fatal() << "error after translate-to-fuzz";
       }
     }
diff --git a/src/tools/wasm-shell.cpp b/src/tools/wasm-shell.cpp
index c0d02ee15..08c76ac9c 100644
--- a/src/tools/wasm-shell.cpp
+++ b/src/tools/wasm-shell.cpp
@@ -28,7 +28,6 @@
 #include "support/command-line.h"
 #include "support/file.h"
 #include "wasm-interpreter.h"
-#include "wasm-printing.h"
 #include "wasm-s-parser.h"
 #include "wasm-validator.h"
 
@@ -311,7 +310,7 @@ int main(int argc, const char* argv[]) {
         modules[moduleName]->features = FeatureSet::All;
         bool valid = WasmValidator().validate(*modules[moduleName]);
         if (!valid) {
-          WasmPrinter::printModule(modules[moduleName].get());
+          std::cout << *modules[moduleName] << '\n';
           Fatal() << "module failed to validate, see above";
         }
         run_asserts(moduleName,
diff --git a/src/tools/wasm2js.cpp b/src/tools/wasm2js.cpp
index 348fc6c10..1464f48f8 100644
--- a/src/tools/wasm2js.cpp
+++ b/src/tools/wasm2js.cpp
@@ -984,7 +984,7 @@ int main(int argc, const char* argv[]) {
 
   if (options.passOptions.validate) {
     if (!WasmValidator().validate(wasm)) {
-      WasmPrinter::printModule(&wasm);
+      std::cout << wasm << '\n';
       Fatal() << "error in validating input";
     }
   }
diff --git a/src/wasm-printing.h b/src/wasm-printing.h
deleted file mode 100644
index 276a387ae..000000000
--- a/src/wasm-printing.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * Copyright 2016 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.
- */
-
-#ifndef wasm_wasm_printing_h
-#define wasm_wasm_printing_h
-
-#include <ostream>
-
-#include "pass.h"
-#include "wasm.h"
-
-namespace wasm {
-
-struct WasmPrinter {
-  static std::ostream& printModule(Module* module, std::ostream& o);
-
-  static std::ostream& printModule(Module* module);
-
-  static std::ostream& printExpression(Expression* expression,
-                                       std::ostream& o,
-                                       bool minify = false,
-                                       bool full = false);
-
-  static std::ostream&
-  printStackInst(StackInst* inst, std::ostream& o, Function* func = nullptr);
-
-  static std::ostream&
-  printStackIR(StackIR* ir, std::ostream& o, Function* func = nullptr);
-};
-
-} // namespace wasm
-
-namespace std {
-
-inline std::ostream& operator<<(std::ostream& o, wasm::Module& module) {
-  return wasm::WasmPrinter::printModule(&module, o);
-}
-
-inline std::ostream& operator<<(std::ostream& o, wasm::Expression& expression) {
-  return wasm::WasmPrinter::printExpression(&expression, o);
-}
-
-inline std::ostream& operator<<(std::ostream& o, wasm::Expression* expression) {
-  return wasm::WasmPrinter::printExpression(expression, o);
-}
-
-inline std::ostream& operator<<(std::ostream& o, wasm::StackInst& inst) {
-  return wasm::WasmPrinter::printStackInst(&inst, o);
-}
-
-inline std::ostream& operator<<(std::ostream& o, wasm::StackIR& ir) {
-  return wasm::WasmPrinter::printStackIR(&ir, o);
-}
-
-} // namespace std
-
-#endif // wasm_wasm_printing_h
diff --git a/src/wasm-validator.h b/src/wasm-validator.h
index 496109a4c..b7f17c19c 100644
--- a/src/wasm-validator.h
+++ b/src/wasm-validator.h
@@ -43,7 +43,6 @@
 #include <sstream>
 #include <unordered_set>
 
-#include "wasm-printing.h"
 #include "wasm.h"
 
 namespace wasm {
diff --git a/src/wasm.h b/src/wasm.h
index 37c12ffc6..8cada039f 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -28,6 +28,7 @@
 #include <array>
 #include <cassert>
 #include <map>
+#include <ostream>
 #include <string>
 #include <vector>
 
@@ -1842,6 +1843,12 @@ template<> struct hash<wasm::Address> {
     return std::hash<wasm::Address::address64_t>()(a.addr);
   }
 };
+
+std::ostream& operator<<(std::ostream& o, wasm::Module& module);
+std::ostream& operator<<(std::ostream& o, wasm::Expression& expression);
+std::ostream& operator<<(std::ostream& o, wasm::StackInst& inst);
+std::ostream& operator<<(std::ostream& o, wasm::StackIR& ir);
+
 } // namespace std
 
 #endif // wasm_wasm_h
diff --git a/src/wasm/wasm-io.cpp b/src/wasm/wasm-io.cpp
index 79687d469..2fb4af838 100644
--- a/src/wasm/wasm-io.cpp
+++ b/src/wasm/wasm-io.cpp
@@ -121,7 +121,7 @@ void ModuleReader::readStdin(Module& wasm, std::string sourceMapFilename) {
 #define DEBUG_TYPE "writer"
 
 void ModuleWriter::writeText(Module& wasm, Output& output) {
-  WasmPrinter::printModule(&wasm, output.getStream());
+  output.getStream() << wasm;
 }
 
 void ModuleWriter::writeText(Module& wasm, std::string filename) {
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index b294c953c..f110faf56 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -25,7 +25,6 @@
 #include "ir/stack-utils.h"
 #include "ir/utils.h"
 #include "support/colors.h"
-#include "wasm-printing.h"
 #include "wasm-validator.h"
 #include "wasm.h"
 
@@ -41,10 +40,12 @@ inline std::ostream& printModuleComponent(T curr, std::ostream& stream) {
   return stream;
 }
 
-// Extra overload for Expressions, to print type info too
+// Extra overload for Expressions, to print their contents.
 inline std::ostream& printModuleComponent(Expression* curr,
                                           std::ostream& stream) {
-  WasmPrinter::printExpression(curr, stream, false, true) << std::endl;
+  if (curr) {
+    stream << *curr << '\n';
+  }
   return stream;
 }
 
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index d9ca03185..90120233d 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -16,7 +16,6 @@
 
 #include "wasm.h"
 #include "ir/branch-utils.h"
-#include "wasm-printing.h"
 #include "wasm-traversal.h"
 
 namespace wasm {
@@ -99,12 +98,7 @@ Name ATTR("attr");
 
 // Expressions
 
-void Expression::dump() {
-  WasmPrinter::printExpression(this,
-                               std::cerr,
-                               /*minify=*/false,
-                               /*full=*/true);
-}
+void Expression::dump() { std::cout << *this << '\n'; }
 
 const char* getExpressionName(Expression* curr) {
   switch (curr->_id) {
diff --git a/src/wasm2js.h b/src/wasm2js.h
index ddc3d7313..5257e3456 100644
--- a/src/wasm2js.h
+++ b/src/wasm2js.h
@@ -404,7 +404,7 @@ Ref Wasm2JSBuilder::processWasm(Module* wasm, Name funcName) {
 
 #ifndef NDEBUG
   if (!WasmValidator().validate(*wasm)) {
-    WasmPrinter::printModule(wasm);
+    std::cout << *wasm << '\n';
     Fatal() << "error in validating wasm2js output";
   }
 #endif
diff --git a/test/binaryen.js/kitchen-sink.js.txt b/test/binaryen.js/kitchen-sink.js.txt
index 464862159..7f0b6043f 100644
--- a/test/binaryen.js/kitchen-sink.js.txt
+++ b/test/binaryen.js/kitchen-sink.js.txt
@@ -4391,8 +4391,8 @@ module loaded from binary form:
 )
 
 [wasm-validator error in function func] local.set's value type must be correct, on 
-[none] (local.set $0
- [i64] (i64.const 1234)
+(local.set $0
+ (i64.const 1234)
 )
 validation: 0
 test_parsing text:
diff --git a/test/binaryen.js/validation_errors.js.txt b/test/binaryen.js/validation_errors.js.txt
index 19b772e98..9e4bb1a75 100644
--- a/test/binaryen.js/validation_errors.js.txt
+++ b/test/binaryen.js/validation_errors.js.txt
@@ -1,6 +1,6 @@
 [wasm-validator error in function test] unexpected false: global.get name must be valid, on 
-[i32] (global.get $missing)
+(global.get $missing)
 0
 [wasm-validator error in function test] unexpected false: local.get index must be small enough, on 
-[i32] (local.get $0)
+(local.get $0)
 0
diff --git a/test/example/module-splitting.cpp b/test/example/module-splitting.cpp
index bba0bf0a7..ad0da84a8 100644
--- a/test/example/module-splitting.cpp
+++ b/test/example/module-splitting.cpp
@@ -4,7 +4,6 @@
 #include "ir/module-splitting.h"
 #include "ir/stack-utils.h"
 #include "wasm-features.h"
-#include "wasm-printing.h"
 #include "wasm-s-parser.h"
 #include "wasm-validator.h"
 #include "wasm.h"
@@ -34,7 +33,7 @@ void do_test(const std::set<Name>& keptFuncs, std::string&& module) {
   assert(valid && "before invalid!");
 
   std::cout << "Before:\n";
-  WasmPrinter::printModule(primary.get());
+  std::cout << *primary.get();
 
   std::cout << "Keeping: ";
   if (keptFuncs.size()) {
@@ -54,9 +53,9 @@ void do_test(const std::set<Name>& keptFuncs, std::string&& module) {
   auto secondary = splitFunctions(*primary, config);
 
   std::cout << "After:\n";
-  WasmPrinter::printModule(primary.get());
+  std::cout << *primary.get();
   std::cout << "Secondary:\n";
-  WasmPrinter::printModule(secondary.get());
+  std::cout << *secondary.get();
   std::cout << "\n\n";
 
   valid = validator.validate(*primary);
diff --git a/test/example/stack-utils.cpp b/test/example/stack-utils.cpp
index 9f20b8c2a..96bc6fb85 100644
--- a/test/example/stack-utils.cpp
+++ b/test/example/stack-utils.cpp
@@ -5,7 +5,6 @@
 #include "literal.h"
 #include "mixed_arena.h"
 #include "wasm-builder.h"
-#include "wasm-printing.h"
 #include "wasm-type.h"
 #include "wasm.h"
 
@@ -26,11 +25,9 @@ void test_remove_nops() {
       builder.makeNop(),
     },
     {Type::i32, Type::i64});
-  WasmPrinter::printExpression(block, std::cout);
-  std::cout << "\n";
+  std::cout << *block << '\n';
   StackUtils::removeNops(block);
-  WasmPrinter::printExpression(block, std::cout);
-  std::cout << "\n";
+  std::cout << *block << '\n';
 }
 
 void test_stack_signatures() {