From 1865f2965b875c21b4bcba6d90d59379c9e6f813 Mon Sep 17 00:00:00 2001
From: Johan Engelen <jbc.engelen@gmail.com>
Date: Sat, 9 Mar 2019 23:18:42 +0100
Subject: [PATCH] Add weka option -template-codegen-depth=<uint> to prevent
 crashes on stack exhaustion upon deep recursion

---
 dmd/dtemplate.d       | 10 ++++++++++
 dmd/globals.d         |  1 +
 dmd/globals.h         |  1 +
 driver/cl_options.cpp |  4 ++++
 4 files changed, 16 insertions(+)

diff --git a/dmd/dtemplate.d b/dmd/dtemplate.d
index f8fc3b28181..86f79da5362 100644
--- a/dmd/dtemplate.d
+++ b/dmd/dtemplate.d
@@ -6217,6 +6217,16 @@ extern (C++) class TemplateInstance : ScopeDsymbol
      */
     final bool needsCodegen()
     {
+        version (IN_WEKA)
+        {
+            static uint callDepth;
+            callDepth++;
+            scope(exit) callDepth--;
+
+            if (global.params.templateCodegenDepth && (callDepth > global.params.templateCodegenDepth))
+                return false;
+        }
+
         // Now -allInst is just for the backward compatibility.
         if (global.params.allInst)
         {
diff --git a/dmd/globals.d b/dmd/globals.d
index a8958f939dc..e996542de9c 100644
--- a/dmd/globals.d
+++ b/dmd/globals.d
@@ -287,6 +287,7 @@ struct Param
         version (IN_WEKA)
         {
             bool enableWekaMods; // Enable specific Weka mods like the template instantiation mods
+            uint templateCodegenDepth; // Don't codegen templates beyond this recusion depth.
         }
     }
 }
diff --git a/dmd/globals.h b/dmd/globals.h
index c5430c7e835..2e894ff3f3e 100644
--- a/dmd/globals.h
+++ b/dmd/globals.h
@@ -255,6 +255,7 @@ struct Param
 
 #if IN_WEKA
     bool enableWekaMods; // Enable specific Weka mods like the template instantiation mods
+    uint32_t templateCodegenDepth;
 #endif
 #endif
 };
diff --git a/driver/cl_options.cpp b/driver/cl_options.cpp
index 58d4aae2932..f3008796804 100644
--- a/driver/cl_options.cpp
+++ b/driver/cl_options.cpp
@@ -432,6 +432,10 @@ static cl::opt<bool, true, FlagParser<bool>> wekaMods(
     cl::desc(
         "(*) Enable specific Weka mods like the template instantiation mods"),
     cl::location(global.params.enableWekaMods), cl::init(true));
+static cl::opt<uint32_t, true>
+    templateCodegenDepth("template-codegen-depth",
+             cl::desc("Don't codegen templates beyond this recusion depth (0 = off)."),
+             cl::location(global.params.templateCodegenDepth), cl::init(0));
 #endif
 
 cl::opt<LTOKind> ltoMode(