Rewrite boxed_region/memory_region in Rust

This drops more of the old C++ runtime to rather be written in rust. A few
features were lost along the way, but hopefully not too many. The main loss is
that there are no longer backtraces associated with allocations (rust doesn't
have a way of acquiring those just yet). Other than that though, I believe that
the rest of the debugging utilities made their way over into rust.

Closes #8704

1 files changed, 9 insertions, 0 deletions

diff --git a/src/libstd/rt/env.rs b/src/libstd/rt/env.rs
index c02e7fe9013..0811f7bbbdc 100644
--- a/src/libstd/rt/env.rs
+++ b/src/libstd/rt/env.rs
@@ -19,6 +19,7 @@ use os;
 
 static mut MIN_STACK: uint = 4000000;
 static mut DEBUG_BORROW: bool = false;
+static mut POISON_ON_FREE: bool = false;
 
 pub fn init() {
     unsafe {
@@ -33,6 +34,10 @@ pub fn init() {
             Some(_) => DEBUG_BORROW = true,
             None => ()
         }
+        match os::getenv("RUST_POISON_ON_FREE") {
+            Some(_) => POISON_ON_FREE = true,
+            None => ()
+        }
     }
 }
 
@@ -43,3 +48,7 @@ pub fn min_stack() -> uint {
 pub fn debug_borrow() -> bool {
     unsafe { DEBUG_BORROW }
 }
+
+pub fn poison_on_free() -> bool {
+    unsafe { POISON_ON_FREE }
+}