[PATCH] D18854: [sanitizer] Fix sem_init_glibc.cc test on __HAVE_64B_ATOMIC arches.

[Marcin Kościelnicki via llvm-commits]

koriakin created this revision.
koriakin added reviewers: samsonov, eugenis.
koriakin added a subscriber: llvm-commits.
koriakin set the repository for this revision to rL LLVM.
koriakin added a project: Sanitizers.

glibc can use one of 2 layouts for semaphores: architectures that
don't __HAVE_64B_ATOMIC use an uint32_t field with semaphore value,
then a private field, then a waiting thread count field - this is
the layout currently assumed by the test.  However, __HAVE_64B_ATOMIC
arches use a fused uint64_t field that contains the value in low bits
and waiting thread count in high bits, followed by a private field.

This resulted in taking private field from the wrong offset on 64-bit
atomic platforms (the test still passed, but didn't actually test
the private field).  On big-endian platforms, this resulted in a fail,
since the first 4 bytes overlay the thread count field, and not
the value field.

Found while porting ASan to s390x.

Repository:
  rL LLVM

http://reviews.llvm.org/D18854

Files:
  test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc

Index: test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc
===================================================================
--- test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc
+++ test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc
@@ -5,21 +5,31 @@
 #include <assert.h>
 #include <semaphore.h>
 #include <string.h>
+#include <stdint.h>
 
-void my_sem_init(bool priv, int value, unsigned *a, unsigned char *b) {
+// This condition needs to correspond to __HAVE_64B_ATOMICS macro in glibc.
+#if defined(__x86_64__) || defined(__aarch64__) || defined(__powerpc64__) || \
+    defined(__s390x__) || defined(__sparc64__) || defined(__alpha__) || \
+    defined(__ia64__) || defined(__m68k__)
+typedef uint64_t semval_t;
+#else
+typedef unsigned semval_t;
+#endif
+
+void my_sem_init(bool priv, int value, semval_t *a, unsigned char *b) {
   sem_t sem;
   memset(&sem, 0xAB, sizeof(sem));
   sem_init(&sem, priv, value);
 
   char *p = (char *)&sem;
-  memcpy(a, p, sizeof(unsigned));
-  memcpy(b, p + sizeof(unsigned), sizeof(char));
+  memcpy(a, p, sizeof(semval_t));
+  memcpy(b, p + sizeof(semval_t), sizeof(char));
 
   sem_destroy(&sem);
 }
 
 int main() {
-  unsigned a;
+  semval_t a;
   unsigned char b;
 
   my_sem_init(false, 42, &a, &b);


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