Merge compiler-rt release_38 branch r258968.

Note that there is still a problem on amd64, causing SIGBUS in the early
startup of Address Sanitizer.  This is being investigated.

1 files changed, 7 insertions, 2 deletions

diff --git a/contrib/compiler-rt/lib/safestack/safestack.cc b/contrib/compiler-rt/lib/safestack/safestack.cc
index 504bd3c..92c24b3 100644
--- a/contrib/compiler-rt/lib/safestack/safestack.cc
+++ b/contrib/compiler-rt/lib/safestack/safestack.cc
@@ -18,6 +18,7 @@
 #include <pthread.h>
 #include <stddef.h>
 #include <stdint.h>
+#include <unistd.h>
 #include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/user.h>
@@ -68,6 +69,9 @@ const unsigned kStackAlign = 16;
 /// size rlimit is set to infinity.
 const unsigned kDefaultUnsafeStackSize = 0x2800000;
 
+/// Runtime page size obtained through sysconf
+static unsigned pageSize;
+
 // TODO: To make accessing the unsafe stack pointer faster, we plan to
 // eventually store it directly in the thread control block data structure on
 // platforms where this structure is pointed to by %fs or %gs. This is exactly
@@ -171,7 +175,7 @@ INTERCEPTOR(int, pthread_create, pthread_t *thread,
   size_t size = 0;
   size_t guard = 0;
 
-  if (attr != NULL) {
+  if (attr) {
     pthread_attr_getstacksize(attr, &size);
     pthread_attr_getguardsize(attr, &guard);
   } else {
@@ -185,7 +189,7 @@ INTERCEPTOR(int, pthread_create, pthread_t *thread,
 
   CHECK_NE(size, 0);
   CHECK_EQ((size & (kStackAlign - 1)), 0);
-  CHECK_EQ((guard & (PAGE_SIZE - 1)), 0);
+  CHECK_EQ((guard & (pageSize - 1)), 0);
 
   void *addr = unsafe_stack_alloc(size, guard);
   struct tinfo *tinfo =
@@ -217,6 +221,7 @@ void __safestack_init() {
   void *addr = unsafe_stack_alloc(size, guard);
 
   unsafe_stack_setup(addr, size, guard);
+  pageSize = sysconf(_SC_PAGESIZE);
 
   // Initialize pthread interceptors for thread allocation
   INTERCEPT_FUNCTION(pthread_create);