Add --print-function-map to print out a map of function index to name (#2155)

* work

* fix

* fix

* format

4 files changed, 50 insertions, 0 deletions

diff --git a/src/passes/CMakeLists.txt b/src/passes/CMakeLists.txt
index 6605d7a09..9120328d3 100644
--- a/src/passes/CMakeLists.txt
+++ b/src/passes/CMakeLists.txt
@@ -43,6 +43,7 @@ SET(passes_SOURCES
   Print.cpp
   PrintCallGraph.cpp
   PrintFeatures.cpp
+  PrintFunctionMap.cpp
   StackIR.cpp
   Strip.cpp
   StripTargetFeatures.cpp
diff --git a/src/passes/PrintFunctionMap.cpp b/src/passes/PrintFunctionMap.cpp
new file mode 100644
index 000000000..75db495fa
--- /dev/null
+++ b/src/passes/PrintFunctionMap.cpp
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2019 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.
+ */
+
+//
+// Prints the a map of function indexes to function names. This can be
+// useful for interpreting a stack trace from a production environment
+// where names did not exist on the client. The map looks like this:
+//
+// 0:foo
+// 1:bar
+// 2:baz
+//
+
+#include "pass.h"
+#include "wasm.h"
+
+namespace wasm {
+
+struct PrintFunctionMap : public Pass {
+  bool modifiesBinaryenIR() override { return false; }
+
+  void run(PassRunner* runner, Module* module) override {
+    Index i = 0;
+    for (auto& func : module->functions) {
+      std::cout << i++ << ':' << func->name.str << '\n';
+    }
+  }
+};
+
+Pass* createPrintFunctionMapPass() { return new PrintFunctionMap(); }
+
+} // namespace wasm
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index 84914f819..c29bb1e1a 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -211,6 +211,9 @@ void PassRegistry::registerPasses() {
     "print-full", "print in full s-expression format", createFullPrinterPass);
   registerPass(
     "print-call-graph", "print call graph", createPrintCallGraphPass);
+  registerPass("print-function-map",
+               "print a map of function indexes to names",
+               createPrintFunctionMapPass);
   registerPass("print-stack-ir",
                "print out Stack IR (useful for internal debugging)",
                createPrintStackIRPass);
diff --git a/src/passes/passes.h b/src/passes/passes.h
index f3bec3f04..f7c8fae77 100644
--- a/src/passes/passes.h
+++ b/src/passes/passes.h
@@ -72,6 +72,7 @@ Pass* createPrecomputePropagatePass();
 Pass* createPrinterPass();
 Pass* createPrintCallGraphPass();
 Pass* createPrintFeaturesPass();
+Pass* createPrintFunctionMapPass();
 Pass* createPrintStackIRPass();
 Pass* createRelooperJumpThreadingPass();
 Pass* createRemoveNonJSOpsPass();