From b0686b1ea71a4651461f640d4803ec0800a182bb Mon Sep 17 00:00:00 2001
From: water111 <48171810+water111@users.noreply.github.com>
Date: Sun, 28 Feb 2021 19:22:53 -0500
Subject: [PATCH] fix decompiler crash (#294)

---
 decompiler/IR2/Env.h                | 12 ++++++++++--
 decompiler/analysis/cfg_builder.cpp | 28 +++++++++++++++-------------
 2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/decompiler/IR2/Env.h b/decompiler/IR2/Env.h
index f29ad150a..00993bc7b 100644
--- a/decompiler/IR2/Env.h
+++ b/decompiler/IR2/Env.h
@@ -114,9 +114,17 @@ class Env {
   }
 
   const UseDefInfo& get_use_def_info(const RegisterAccess& ra) const;
-  void disable_use(const RegisterAccess& access) { m_var_names.disable_use(access); }
+  void disable_use(const RegisterAccess& access) {
+    if (has_local_vars()) {
+      m_var_names.disable_use(access);
+    }
+  }
 
-  void disable_def(const RegisterAccess& access) { m_var_names.disable_def(access); }
+  void disable_def(const RegisterAccess& access) {
+    if (has_local_vars()) {
+      m_var_names.disable_def(access);
+    }
+  }
 
   LinkedObjectFile* file = nullptr;
   DecompilerTypeSystem* dts = nullptr;
diff --git a/decompiler/analysis/cfg_builder.cpp b/decompiler/analysis/cfg_builder.cpp
index f13d971b9..badf03889 100644
--- a/decompiler/analysis/cfg_builder.cpp
+++ b/decompiler/analysis/cfg_builder.cpp
@@ -453,22 +453,24 @@ bool try_clean_up_sc_as_or(FormPool& pool, Function& func, ShortCircuitElement*
       // we also want to fix up the use/def info for the result.
       // it's somewhat arbitrary, but we use the convention that the short-circuit defs
       // are eliminated:
-      auto& ud_info = func.ir2.env.get_use_def_info(as_set->dst());
-      if (i == int(ir->entries.size()) - 2) {
-        if (ud_info.def_count() == 1) {
-          // the final case of the or doesn't explicitly set the destination register.
-          // this can happen if the move is eliminated during coloring.
-          // for now, let's leave this last def here, just so it looks like _something_ sets it.
-          // TODO - what if this isn't a def in the last slot? Does it matter?
+      if (func.ir2.env.has_local_vars()) {
+        auto& ud_info = func.ir2.env.get_use_def_info(as_set->dst());
+        if (i == int(ir->entries.size()) - 2) {
+          if (ud_info.def_count() == 1) {
+            // the final case of the or doesn't explicitly set the destination register.
+            // this can happen if the move is eliminated during coloring.
+            // for now, let's leave this last def here, just so it looks like _something_ sets it.
+            // TODO - what if this isn't a def in the last slot? Does it matter?
+          } else {
+            // lg::warn("Disabling def of {} in final or delay slot",
+            // as_set->to_string(func.ir2.env));
+            func.ir2.env.disable_def(as_set->dst());
+          }
+
         } else {
-          // lg::warn("Disabling def of {} in final or delay slot",
-          // as_set->to_string(func.ir2.env));
+          // lg::warn("Disabling def of {} in or delay slot", as_set->to_string(func.ir2.env));
           func.ir2.env.disable_def(as_set->dst());
         }
-
-      } else {
-        // lg::warn("Disabling def of {} in or delay slot", as_set->to_string(func.ir2.env));
-        func.ir2.env.disable_def(as_set->dst());
       }
 
       if (i == 0) {