Add Valgrind poison stubs

SConstruct

@@ -757,6 +757,27 @@ int main(int, char **){{
 		if self.Compile(context, text=text.format(type=','.join(('int',)*count), value=','.join(('0',)*count)), msg='whether compiler handles 2-element tuples'):
 			raise SCons.Errors.StopError("Compiler cannot handle tuples of 20 elements.  Raise the template instantiation depth.")
 		raise SCons.Errors.StopError("Compiler cannot handle tuples of 2 elements.")
+	@_implicit_test
+	def check_poison_valgrind(self,context):
+		context.Display('%s: checking %s...' % (self.msgprefix, 'whether to use Valgrind poisoning'))
+		r = self.user_settings.poison == 'valgrind'
+		context.Result(r)
+		if not r:
+			return
+		text = '''
+#include "poison.h"
+int main(int argc,char**) {
+	DXX_MAKE_MEM_UNDEFINED(&argc, sizeof(argc));
+	return 0;
+}
+'''
+		if self.Compile(context, text=text, msg='whether Valgrind memcheck header works', successflags={'CPPDEFINES' : ['DXX_HAVE_POISON_VALGRIND']}):
+			return True
+		raise SCons.Errors.StopError("Valgrind poison requested, but <valgrind/memcheck.h> does not work.")
+	@_custom_test
+	def _check_poison_method(self,context):
+		if self.check_poison_valgrind(context):
+			context.sconf.Define('DXX_HAVE_POISON')
 
 class LazyObjectConstructor:
 	def __lazy_objects(self,name,source):
@@ -943,6 +964,7 @@ class DXXCommon(LazyObjectConstructor):
 				'variable': self._enum_variable,
 				'arguments': (
 					('host_platform', 'linux' if sys.platform == 'linux2' else sys.platform, 'cross-compile to specified platform', {'allowed_values' : ['win32', 'darwin', 'linux']}),
+					('poison', 'none', 'method for poisoning free memory', {'allowed_values' : ('none', 'valgrind')}),
 				),
 			},
 			{

common/include/poison.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#ifdef DXX_HAVE_POISON_VALGRIND
+#include <valgrind/memcheck.h>
+#endif
+
+template <typename T>
+static inline void DXX_MAKE_MEM_UNDEFINED(T *b, unsigned long l)
+{
+	(void)b;(void)l;
+#ifdef DXX_HAVE_POISON_VALGRIND
+	VALGRIND_MAKE_MEM_UNDEFINED(b, l);
+#endif
+}
+
+template <typename T>
+static inline void DXX_MAKE_MEM_UNDEFINED(T *b, T *e)
+{
+	DXX_MAKE_MEM_UNDEFINED(b, e - b);
+}
+
+template <typename T, typename V>
+static inline void _DXX_POISON_MEMORY_RANGE(T b, T e, const V &v)
+{
+#ifdef DXX_HAVE_POISON
+	int store = 0;
+#ifdef DXX_HAVE_POISON_VALGRIND
+	store |= RUNNING_ON_VALGRIND;
+#endif
+	if (!store)
+		return;
+	for (; b != e; ++b)
+		*b = v;
+#else
+	(void)b;(void)e;(void)v;
+#endif
+}
+
+template <typename T, typename V>
+static inline void DXX_POISON_MEMORY(T b, unsigned long l, const V &v)
+{
+	_DXX_POISON_MEMORY_RANGE(b, b + l, v);
+	DXX_MAKE_MEM_UNDEFINED(b, l);
+}
+
+template <typename T, typename V>
+static inline void DXX_POISON_MEMORY(T b, T e, const V &v)
+{
+	_DXX_POISON_MEMORY_RANGE(b, e, v);
+	DXX_MAKE_MEM_UNDEFINED(b, e);
+}

similar/misc/physfsx.cpp

@@ -26,6 +26,8 @@
 #include "strutil.h"
 #include "ignorecase.h"
 
+#include "poison.h"
+
 static const file_extension_t archive_exts[] = { "dxa", "" };
 
 char *PHYSFSX_fgets(char *buf, size_t n, PHYSFS_file *const fp)
@@ -59,7 +61,8 @@ char *PHYSFSX_fgets(char *buf, size_t n, PHYSFS_file *const fp)
 		++p;
 	}
 	PHYSFS_seek(fp, t + (p - buf) + 1);
-	std::fill(p, buf + n, 0);
+	*p = 0;
+	DXX_POISON_MEMORY(p + 1, buf + n, 0xcc);
 	return buf;
 }