bpo-35214: Initial clang MemorySanitizer support (GH-10479)
Adds configure flags for msan and ubsan builds to make it easier to enable.
These also encode the detail that address sanitizer and memory sanitizer
should disable pymalloc.
Define MEMORY_SANITIZER when appropriate at build time and adds workarounds
to existing code to mark things as initialized where the sanitizer is otherwise unable to
determine that. This lets our build succeed under the memory sanitizer. not all tests
pass without sanitizer failures yet but we're in pretty good shape after this.
diff --git a/Modules/_posixsubprocess.c b/Modules/_posixsubprocess.c
index 9661e38..7ee3f71 100644
--- a/Modules/_posixsubprocess.c
+++ b/Modules/_posixsubprocess.c
@@ -21,6 +21,10 @@
#include <dirent.h>
#endif
+#ifdef MEMORY_SANITIZER
+# include <sanitizer/msan_interface.h>
+#endif
+
#if defined(__ANDROID__) && __ANDROID_API__ < 21 && !defined(SYS_getdents64)
# include <sys/linux-syscalls.h>
# define SYS_getdents64 __NR_getdents64
@@ -287,6 +291,9 @@
sizeof(buffer))) > 0) {
struct linux_dirent64 *entry;
int offset;
+#ifdef MEMORY_SANITIZER
+ __msan_unpoison(buffer, bytes);
+#endif
for (offset = 0; offset < bytes; offset += entry->d_reclen) {
int fd;
entry = (struct linux_dirent64 *)(buffer + offset);