diff --git a/src/compiler/DetectCallDepth.cpp b/src/compiler/DetectCallDepth.cpp
new file mode 100644
index 0000000..60df52c
--- /dev/null
+++ b/src/compiler/DetectCallDepth.cpp
@@ -0,0 +1,185 @@
+//
+// Copyright (c) 2002-2011 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+#include "compiler/DetectCallDepth.h"
+#include "compiler/InfoSink.h"
+
+DetectCallDepth::FunctionNode::FunctionNode(const TString& fname)
+    : name(fname),
+      visit(PreVisit)
+{
+}
+
+const TString& DetectCallDepth::FunctionNode::getName() const
+{
+    return name;
+}
+
+void DetectCallDepth::FunctionNode::addCallee(
+    DetectCallDepth::FunctionNode* callee)
+{
+    for (size_t i = 0; i < callees.size(); ++i) {
+        if (callees[i] == callee)
+            return;
+    }
+    callees.push_back(callee);
+}
+
+int DetectCallDepth::FunctionNode::detectCallDepth(DetectCallDepth* detectCallDepth, int depth)
+{
+    ASSERT(visit == PreVisit);
+    ASSERT(detectCallDepth);
+
+    int maxDepth = depth;
+    visit = InVisit;
+    for (size_t i = 0; i < callees.size(); ++i) {
+        switch (callees[i]->visit) {
+            case InVisit:
+                // cycle detected, i.e., recursion detected.
+                return kInfiniteCallDepth;
+            case PostVisit:
+                break;
+            case PreVisit: {
+                // Check before we recurse so we don't go too depth
+                if (detectCallDepth->checkExceedsMaxDepth(depth))
+                    return depth;
+                int callDepth = callees[i]->detectCallDepth(detectCallDepth, depth + 1);
+                // Check after we recurse so we can exit immediately and provide info.
+                if (detectCallDepth->checkExceedsMaxDepth(callDepth)) {
+                    detectCallDepth->getInfoSink().info << "<-" << callees[i]->getName();
+                    return callDepth;
+                }
+                maxDepth = std::max(callDepth, maxDepth);
+                break;
+            }
+            default:
+                UNREACHABLE();
+                break;
+        }
+    }
+    visit = PostVisit;
+    return maxDepth;
+}
+
+void DetectCallDepth::FunctionNode::reset()
+{
+    visit = PreVisit;
+}
+
+DetectCallDepth::DetectCallDepth(TInfoSink& infoSink, bool limitCallStackDepth, int maxCallStackDepth)
+    : TIntermTraverser(true, false, true, false),
+      currentFunction(NULL),
+      infoSink(infoSink),
+      maxDepth(limitCallStackDepth ? maxCallStackDepth : FunctionNode::kInfiniteCallDepth)
+{
+}
+
+DetectCallDepth::~DetectCallDepth()
+{
+    for (size_t i = 0; i < functions.size(); ++i)
+        delete functions[i];
+}
+
+bool DetectCallDepth::visitAggregate(Visit visit, TIntermAggregate* node)
+{
+    switch (node->getOp())
+    {
+        case EOpPrototype:
+            // Function declaration.
+            // Don't add FunctionNode here because node->getName() is the
+            // unmangled function name.
+            break;
+        case EOpFunction: {
+            // Function definition.
+            if (visit == PreVisit) {
+                currentFunction = findFunctionByName(node->getName());
+                if (currentFunction == NULL) {
+                    currentFunction = new FunctionNode(node->getName());
+                    functions.push_back(currentFunction);
+                }
+            } else if (visit == PostVisit) {
+                currentFunction = NULL;
+            }
+            break;
+        }
+        case EOpFunctionCall: {
+            // Function call.
+            if (visit == PreVisit) {
+                FunctionNode* func = findFunctionByName(node->getName());
+                if (func == NULL) {
+                    func = new FunctionNode(node->getName());
+                    functions.push_back(func);
+                }
+                if (currentFunction)
+                    currentFunction->addCallee(func);
+            }
+            break;
+        }
+        default:
+            break;
+    }
+    return true;
+}
+
+bool DetectCallDepth::checkExceedsMaxDepth(int depth)
+{
+    return depth >= maxDepth;
+}
+
+void DetectCallDepth::resetFunctionNodes()
+{
+    for (size_t i = 0; i < functions.size(); ++i) {
+        functions[i]->reset();
+    }
+}
+
+DetectCallDepth::ErrorCode DetectCallDepth::detectCallDepthForFunction(FunctionNode* func)
+{
+    currentFunction = NULL;
+    resetFunctionNodes();
+
+    int maxCallDepth = func->detectCallDepth(this, 1);
+
+    if (maxCallDepth == FunctionNode::kInfiniteCallDepth)
+        return kErrorRecursion;
+
+    if (maxCallDepth >= maxDepth)
+        return kErrorMaxDepthExceeded;
+
+    return kErrorNone;
+}
+
+DetectCallDepth::ErrorCode DetectCallDepth::detectCallDepth()
+{
+    if (maxDepth != FunctionNode::kInfiniteCallDepth) {
+        // Check all functions because the driver may fail on them
+        // TODO: Before detectingRecursion, strip unused functions.
+        for (size_t i = 0; i < functions.size(); ++i) {
+            ErrorCode error = detectCallDepthForFunction(functions[i]);
+            if (error != kErrorNone)
+                return error;
+        }
+    } else {
+        FunctionNode* main = findFunctionByName("main(");
+        if (main == NULL)
+            return kErrorMissingMain;
+
+        return detectCallDepthForFunction(main);
+    }
+
+    return kErrorNone;
+}
+
+DetectCallDepth::FunctionNode* DetectCallDepth::findFunctionByName(
+    const TString& name)
+{
+    for (size_t i = 0; i < functions.size(); ++i) {
+        if (functions[i]->getName() == name)
+            return functions[i];
+    }
+    return NULL;
+}
+