[compiler-rt][asan][test] Make wchar tests more robust

The stack buffer which is used to trigger out of bounds issue doesn't
have obervable side effects, so it can easily be optimized by compiler
as dead code.

Signed-off-by: Maosu Zhao <[email protected]>

Author: zhaomaosu

compiler-rt/test/asan/TestCases/wcscat.cpp

@@ -9,11 +9,13 @@
 int main() {
   const wchar_t *start = L"X means ";
   const wchar_t *append = L"dog";
-  wchar_t goodDst[12];
+  wchar_t goodArray[12];
+  wchar_t *volatile goodDst = goodArray;
   wcscpy(goodDst, start);
   wcscat(goodDst, append);
 
-  wchar_t badDst[9];
+  wchar_t badArray[9];
+  wchar_t *volatile badDst = badArray;
   wcscpy(badDst, start);
   fprintf(stderr, "Good so far.\n");
   // CHECK-DAG: Good so far.

compiler-rt/test/asan/TestCases/wcscpy.cpp

@@ -8,10 +8,12 @@
 
 int main() {
   const wchar_t *src = L"X means dog";
-  wchar_t goodDst[12];
+  wchar_t goodArray[12];
+  wchar_t *volatile goodDst = goodArray;
   wcscpy(goodDst, src);
 
-  wchar_t badDst[7];
+  wchar_t badArray[7];
+  wchar_t *volatile badDst = badArray;
   fprintf(stderr, "Good so far.\n");
   // CHECK-DAG: Good so far.
   fflush(stderr);

compiler-rt/test/asan/TestCases/wcsncat.cpp

@@ -9,11 +9,13 @@
 int main() {
   const wchar_t *start = L"X means ";
   const wchar_t *append = L"dog";
-  wchar_t goodDst[15];
+  wchar_t goodArray[15];
+  wchar_t *volatile goodDst = goodArray;
   wcscpy(goodDst, start);
   wcsncat(goodDst, append, 5);
 
-  wchar_t badDst[11];
+  wchar_t badArray[11];
+  wchar_t *volatile badDst = badArray;
   wcscpy(badDst, start);
   wcsncat(badDst, append, 1);
   fprintf(stderr, "Good so far.\n");

compiler-rt/test/asan/TestCases/wcsncpy.cpp

@@ -8,10 +8,12 @@
 
 int main() {
   const wchar_t *src = L"X means dog";
-  wchar_t goodDst[12];
+  wchar_t goodArray[12];
+  wchar_t *volatile goodDst = goodArray;
   wcsncpy(goodDst, src, 12);
 
-  wchar_t badDst[7];
+  wchar_t badArray[7];
+  wchar_t *volatile badDst = badArray;
   wcsncpy(badDst, src, 7); // This should still work.
   fprintf(stderr, "Good so far.\n");
   // CHECK-DAG: Good so far.