From 04bbeb88f4876dcc75c0b97a745596f723a28be8 Mon Sep 17 00:00:00 2001
From: edef <edef@edef.eu>
Date: Wed, 15 Apr 2015 22:45:50 -0400
Subject: [PATCH] add valgrind_stack_change

Unlike valgrind_stack_register, this won't automatically swap
if `start > end`. It's probably wiser to pretend it doesn't swap at all.
---
 src/valgrind.c  | 4 ++++
 src/valgrind.rs | 9 +++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/valgrind.c b/src/valgrind.c
index 42362d3..fce9486 100644
--- a/src/valgrind.c
+++ b/src/valgrind.c
@@ -7,6 +7,10 @@ valgrind_stack_id_t valgrind_stack_register(const void *start, const void *end)
   return VALGRIND_STACK_REGISTER(start, end);
 }
 
+void valgrind_stack_change(valgrind_stack_id_t id, const void *start, const void *end) {
+  VALGRIND_STACK_CHANGE(id, start, end);
+}
+
 void valgrind_stack_deregister(valgrind_stack_id_t id) {
   VALGRIND_STACK_DEREGISTER(id);
 }
diff --git a/src/valgrind.rs b/src/valgrind.rs
index f1d5e10..37848ff 100644
--- a/src/valgrind.rs
+++ b/src/valgrind.rs
@@ -1,6 +1,6 @@
 #![allow(non_camel_case_types)]
 //! In order for Valgrind to keep track of stack overflows and such, it needs
-//! a little help. That help unfortunately comes in the form of a pair of C
+//! a little help. That help unfortunately comes in the form of a set of C
 //! macros. Calling out to un-inlineable C code for this is pointlessly slow,
 //! but that's the way it is for now.
 
@@ -9,9 +9,14 @@ extern "C" {
   #[link_name = "valgrind_stack_register"]
   /// Register a stack with Valgrind. Returns an integer ID that can
   /// be used to deregister the stack when it's deallocated.
-  /// `start < end`, though Valgrind will happily accept either.
+  /// `start < end`.
   pub fn stack_register(start: *const u8, end: *const u8) -> stack_id_t;
 
+  #[link_name = "valgrind_stack_change"]
+  /// Change the size or location of a stack registered with Valgrind.
+  /// `start < end`.
+  pub fn stack_change(id: stack_id_t, start: *const u8, end: *const u8) -> stack_id_t;
+
   #[link_name = "valgrind_stack_deregister"]
   /// Deregister a stack from Valgrind. Takes the integer ID that was returned
   /// on registration.