From: Ivan Maidanski <ivmai@mail.ru>
Date: Sat, 17 Dec 2016 14:21:40 +0000 (+0300)
Subject: Workaround 'bad address arithmetic' static analysis tool false positive
X-Git-Tag: v7.6.2~262
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8d56af65332ed54500899a74439bd30985d5b209;p=gc

Workaround 'bad address arithmetic' static analysis tool false positive

The tool complains whether (alloc(size)+ofs) is intentional instead of
(alloc(size+ofs)).  In our case, it is a false alarm (the offset is
added to the result to align the allocation at HBLKSIZE boundary).

* os_dep.c [USE_WINALLOC && MSWIN32] (GC_win32_get_mem): Store result
of GlobalAlloc() to "result" local variable first (then, perform result
alignment in a standalone statement); add comment.
---

diff --git a/os_dep.c b/os_dep.c
index 23c8663b..8016542b 100644
--- a/os_dep.c
+++ b/os_dep.c
@@ -2306,8 +2306,10 @@ void * os2_alloc(size_t bytes)
         /* VirtualAlloc doesn't like PAGE_EXECUTE_READWRITE.    */
         /* There are also unconfirmed rumors of other           */
         /* problems, so we dodge the issue.                     */
-        result = (ptr_t)(((word)GlobalAlloc(0, SIZET_SAT_ADD(bytes, HBLKSIZE))
-                            + HBLKSIZE - 1) & ~(word)(HBLKSIZE - 1));
+        result = (ptr_t)GlobalAlloc(0, SIZET_SAT_ADD(bytes, HBLKSIZE));
+        /* Align it at HBLKSIZE boundary.       */
+        result = (ptr_t)(((word)result + HBLKSIZE - 1)
+                         & ~(word)(HBLKSIZE - 1));
       } else
 #   endif
     /* else */ {