From edc885ac79cee38da20f8e8b17ccc10fb625403e Mon Sep 17 00:00:00 2001
From: Andrea Mazzoleni <amadvance@gmail.com>
Date: Thu, 27 Jun 2013 21:59:19 +0200
Subject: [PATCH] Adds support for the valgrind tool sgcheck.

---
 configure.ac | 12 ++++++++++--
 sgcheck.supp |  7 +++++++
 tommychain.h | 11 ++++++-----
 3 files changed, 23 insertions(+), 7 deletions(-)
 create mode 100644 sgcheck.supp

diff --git a/configure.ac b/configure.ac
index 7e4ba7be..923737bc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -9,7 +9,7 @@ AC_CANONICAL_HOST
 dnl Checks for programs.
 AC_PROG_CC
 AC_USE_SYSTEM_EXTENSIONS
-AC_CHECK_PROG([VALGRIND],[valgrind],[valgrind --leak-check=full --track-fds=yes --error-exitcode=1],[])
+AC_CHECK_PROG([VALGRIND],[valgrind],[valgrind],[])
 AC_CHECK_PROG([WINE],[wine],[wine],[])
 AC_CHECK_PROG([ADVD2],[advd2],[advd2],[])
 AM_CONDITIONAL(HAVE_ADVD2, [test x"$ADVD2" != x])
@@ -85,7 +85,15 @@ AC_ARG_ENABLE([coverage],
 AC_ARG_ENABLE([valgrind],
 	[AS_HELP_STRING([--enable-valgrind],[enable the use of valgrind in testing])],
 	[
-	TESTENV="$VALGRIND"
+	TESTENV="$VALGRIND --leak-check=full --track-fds=yes --error-exitcode=1"
+	CFLAGS="$CFLAGS -DCHECKER"
+	],
+	[])
+
+AC_ARG_ENABLE([sgcheck],
+	[AS_HELP_STRING([--enable-sgcheck],[enable the use of sgcheck in testing])],
+	[
+	TESTENV="$VALGRIND --tool=exp-sgcheck --suppressions=sgcheck.supp --error-exitcode=1"
 	CFLAGS="$CFLAGS -DCHECKER"
 	],
 	[])
diff --git a/sgcheck.supp b/sgcheck.supp
new file mode 100644
index 00000000..76817cc4
--- /dev/null
+++ b/sgcheck.supp
@@ -0,0 +1,7 @@
+{
+   printf reports false positves when printing more than one variables at time
+   exp-sgcheck:SorG
+   ...
+   fun:printf
+}
+
diff --git a/tommychain.h b/tommychain.h
index bc4a436d..bc9b3049 100644
--- a/tommychain.h
+++ b/tommychain.h
@@ -158,8 +158,10 @@ tommy_inline void tommy_chain_mergesort(tommy_chain* chain, tommy_compare_func*
 	/*
 	 * Bit buckets of chains.
 	 * Each bucket contains 2^i nodes or it's empty.
+	 * The chain at address TOMMY_CHAIN_BIT_MAX is an independet variable operating as "carry".
+	 * We keep it in the same "bit" vector to avoid reports from the valgrind tool sgcheck.
 	 */
-	tommy_chain bit[TOMMY_CHAIN_BIT_MAX];
+	tommy_chain bit[TOMMY_CHAIN_BIT_MAX + 1];
 
 	/**
 	 * Value stored inside the bit bucket.
@@ -174,13 +176,12 @@ tommy_inline void tommy_chain_mergesort(tommy_chain* chain, tommy_compare_func*
 	counter = 0;
 	while (1) {
 		tommy_node* next;
-		tommy_chain carry;
 		tommy_chain* last;
 
 		/* carry bit to add */
-		last = &carry;
-		carry.head = node;
-		carry.tail = node;
+		last = &bit[TOMMY_CHAIN_BIT_MAX];
+		bit[TOMMY_CHAIN_BIT_MAX].head = node;
+		bit[TOMMY_CHAIN_BIT_MAX].tail = node;
 		next = node->next;
 
 		/* add the bit, propagating the carry */