4 files changed, 118 insertions, 0 deletions
diff --git a/src/passes/CMakeLists.txt b/src/passes/CMakeLists.txt
index 3f6574ec4..eadc69e0a 100644
--- a/src/passes/CMakeLists.txt
+++ b/src/passes/CMakeLists.txt
@@ -13,6 +13,7 @@ SET(passes_SOURCES
   PostEmscripten.cpp
   Precompute.cpp
   Print.cpp
+  PrintCallGraph.cpp
   RelooperJumpThreading.cpp
   RemoveImports.cpp
   RemoveMemory.cpp
diff --git a/src/passes/PrintCallGraph.cpp b/src/passes/PrintCallGraph.cpp
new file mode 100644
index 000000000..33fcb3457
--- /dev/null
+++ b/src/passes/PrintCallGraph.cpp
@@ -0,0 +1,115 @@
+/*
+ * 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.
+ */
+
+//
+// Prints the call graph in .dot format. You can use http://www.graphviz.org/ to view .dot files.
+//
+
+
+#include <memory>
+#include <iomanip>
+#include "wasm.h"
+#include "pass.h"
+#include "ast_utils.h"
+
+namespace wasm {
+
+struct PrintCallGraph : public Pass {
+  void run(PassRunner* runner, Module* module) override {
+    std::ostream &o = std::cout;
+    o << "digraph call {\n";
+    o << "  rankdir = LR;\n";
+    o << "  subgraph cluster_key {\n";
+    o << "    node [shape=box, style=rounded, fontname=courier, fontsize=10];\n";
+    o << "    edge [fontname=courier, fontsize=10];\n";
+    o << "    label = \"Key\";\n";
+    o << "    \"Import\" [style=\"filled, rounded\", fillcolor=\"turquoise\"];\n";
+    o << "    \"Export\" [style=\"filled, rounded\", fillcolor=\"gray\"];\n";
+    o << "    \"A\" -> \"B\" [style=\"filled, rounded\", label = \"Direct Call\"];\n";
+    o << "    \"C\" -> \"D\" [style=\"filled, rounded, dashed\", label = \"Possible Indirect Call\"];\n";
+    o << "  }\n\n";
+    o << "  node [shape=box,style=rounded, fontname=courier, fontsize=10];\n";
+
+    // Imports Nodes
+    for (auto& curr : module->imports) {
+      if (curr->kind == ExternalKind::Function) {
+        o << "  \"" << curr->name << "\" [style=\"filled, rounded\", fillcolor=\"turquoise\"];\n";
+      }
+    }
+
+    // Exports Nodes
+    for (auto& curr : module->exports) {
+      if (curr->kind == ExternalKind::Function) {
+        Function* func = module->getFunction(curr->value);
+        o << "  \"" << func->name << "\" [style=\"filled, rounded\", fillcolor=\"gray\"];\n";
+      }
+    }
+
+    struct CallPrinter : public PostWalker<CallPrinter, Visitor<CallPrinter>> {
+      Module *module;
+      Function *currFunction;
+      std::set<Name> visitedTargets; // Used to avoid printing duplicate edges.
+      std::vector<Function*> allIndirectTargets;
+      CallPrinter(Module *module) : module(module) {
+        // Gather targets of indirect calls.
+        for (auto& segment : module->table.segments) {
+          for (auto& curr : segment.data) {
+            allIndirectTargets.push_back(module->getFunction(curr));
+          }
+        }
+        // Walk function bodies.
+        for (auto& func : module->functions) {
+          currFunction = func.get();
+          std::cout << "  \"" << func->name << "\";\n";
+          visitedTargets.clear();
+          walk(func.get()->body);
+        }
+      }
+      void visitCall(Call *curr) {
+        auto* target = module->getFunction(curr->target);
+        if (visitedTargets.count(target->name) > 0) return;
+        visitedTargets.insert(target->name);
+        std::cout << "  \"" << currFunction->name << "\" -> \"" << target->name << "\"; // call\n";
+      }
+      void visitCallImport(CallImport *curr) {
+        auto name = curr->target;
+        if (visitedTargets.count(name) > 0) return;
+        visitedTargets.insert(name);
+        std::cout << "  \"" << currFunction->name << "\" -> \"" << name << "\"; // callImport\n";
+      }
+      void visitCallIndirect(CallIndirect *curr) {
+        // Find eligible indirect targets.
+        auto* currType = module->getFunctionType(curr->fullType);
+        for (auto& target : allIndirectTargets) {
+          auto* targetType = module->getFunctionType(target->type);
+          if (targetType->structuralComparison(*currType)) continue;
+          auto name = target->name;
+          if (visitedTargets.count(name) > 0) continue;
+          visitedTargets.insert(name);
+          std::cout << "  \"" << currFunction->name << "\" -> \"" << name << "\" [style=\"dashed\"]; // callIndirect\n";
+        }
+      }
+    };
+    CallPrinter printer(module);
+    o << "}\n";
+  }
+};
+
+Pass *createPrintCallGraphPass() {
+  return new PrintCallGraph();
+}
+
+} // namespace wasm
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index 3ae0819ea..42e74fbb7 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -78,6 +78,7 @@ void PassRegistry::registerPasses() {
   registerPass("print", "print in s-expression format", createPrinterPass);
   registerPass("print-minified", "print in minified s-expression format", createMinifiedPrinterPass);
   registerPass("print-full", "print in full s-expression format", createFullPrinterPass);
+  registerPass("print-call-graph", "print call graph", createPrintCallGraphPass);
   registerPass("relooper-jump-threading", "thread relooper jumps (fastcomp output only)", createRelooperJumpThreadingPass);
   registerPass("remove-imports", "removes imports and replaces them with nops", createRemoveImportsPass);
   registerPass("remove-memory", "removes memory segments", createRemoveMemoryPass);
diff --git a/src/passes/passes.h b/src/passes/passes.h
index 13193bc4c..5bc221ee5 100644
--- a/src/passes/passes.h
+++ b/src/passes/passes.h
@@ -38,6 +38,7 @@ Pass *createNameManagerPass();
 Pass *createOptimizeInstructionsPass();
 Pass *createPostEmscriptenPass();
 Pass *createPrinterPass();
+Pass *createPrintCallGraphPass();
 Pass *createRelooperJumpThreadingPass();
 Pass *createRemoveImportsPass();
 Pass *createRemoveMemoryPass();