[compiler-rt] r199980 - [msan] add __libc_memalign interceptor; add a regression test for the existing bug with dtls support in msan

[Kostya Serebryany]

Author: kcc
Date: Fri Jan 24 03:14:11 2014
New Revision: 199980

URL: http://llvm.org/viewvc/llvm-project?rev=199980&view=rev
Log:
[msan] add __libc_memalign interceptor; add a regression test for the existing bug with dtls support in msan

Added:
    compiler-rt/trunk/lib/msan/lit_tests/dtls_test.c
Modified:
    compiler-rt/trunk/lib/msan/msan_interceptors.cc

Added: compiler-rt/trunk/lib/msan/lit_tests/dtls_test.c
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/lit_tests/dtls_test.c?rev=199980&view=auto
==============================================================================
--- compiler-rt/trunk/lib/msan/lit_tests/dtls_test.c (added)
+++ compiler-rt/trunk/lib/msan/lit_tests/dtls_test.c Fri Jan 24 03:14:11 2014
@@ -0,0 +1,60 @@
+/* RUN: %clang_msan -m64 %s -o %t
+   RUN: %clang_msan -m64 %s -DBUILD_SO -fPIC -o %t-so.so -shared
+   RUN: not %t 2>&1 | FileCheck %s
+   CHECK: MemorySanitizer: use-of-uninitialized-value
+
+   This is an actual bug in msan/glibc integration,
+   see https://sourceware.org/bugzilla/show_bug.cgi?id=16291
+*/
+
+#ifndef BUILD_SO
+#include <assert.h>
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+typedef long *(* get_t)();
+get_t GetTls;
+void *Thread1(void *unused) {
+  long uninitialized;
+  long *x = GetTls();
+  if (*x)
+    fprintf(stderr, "bar\n");
+  *x = uninitialized;
+  fprintf(stderr, "stack: %p dtls: %p\n", &x, x);
+  return 0;
+}
+
+void *Thread2(void *unused) {
+  long *x = GetTls();
+  fprintf(stderr, "stack: %p dtls: %p\n", &x, x);
+  if (*x)
+    fprintf(stderr, "foo\n");   // False negative here.
+  return 0;
+}
+
+int main(int argc, char *argv[]) {
+  char path[4096];
+  snprintf(path, sizeof(path), "%s-so.so", argv[0]);
+  int i;
+
+  void *handle = dlopen(path, RTLD_LAZY);
+  if (!handle) fprintf(stderr, "%s\n", dlerror());
+  assert(handle != 0);
+  GetTls = (get_t)dlsym(handle, "GetTls");
+  assert(dlerror() == 0);
+
+  pthread_t t;
+  pthread_create(&t, 0, Thread1, 0);
+  pthread_join(t, 0);
+  pthread_create(&t, 0, Thread2, 0);
+  pthread_join(t, 0);
+  return 0;
+}
+#else  // BUILD_SO
+__thread long huge_thread_local_array[1 << 17];
+long *GetTls() {
+  return &huge_thread_local_array[0];
+}
+#endif

Modified: compiler-rt/trunk/lib/msan/msan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_interceptors.cc?rev=199980&r1=199979&r2=199980&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/msan/msan_interceptors.cc Fri Jan 24 03:14:11 2014
@@ -159,6 +159,9 @@ INTERCEPTOR(void *, memalign, SIZE_T bou
   return ptr;
 }
 
+INTERCEPTOR(void*, __libc_memalign, uptr align, uptr s)
+  ALIAS("memalign");
+
 INTERCEPTOR(void *, valloc, SIZE_T size) {
   GET_MALLOC_STACK_TRACE;
   void *ptr = MsanReallocate(&stack, 0, size, GetPageSizeCached(), false);