[ubsan] Add runtime test for -fsanitize=local-bounds (#120038)

Author: vitalybuka

compiler-rt/test/ubsan/TestCases/Misc/local_bounds.cpp

@@ -0,0 +1,28 @@
+// RUN: %clangxx -fsanitize=local-bounds %s -O3 -o %t && %run %t 1
+// RUN: %clangxx -fsanitize=local-bounds %s -O3 -o %t && not --crash %run %t 3
+
+// FIXME: it's always trap for now.
+
+#include <cstdlib>
+
+struct S {
+  int k;
+  int l;
+};
+
+__attribute__((noinline)) void init(S *s) {
+  __asm__ __volatile__("" : : "r"(s) : "memory");
+}
+
+__attribute__((noinline, no_sanitize("memory"))) int test(char i) {
+  S a;
+  init(&a);
+  S b;
+  init(&b);
+  return ((int *)(&a))[i];
+}
+
+int main(int argc, char **argv) {
+  test(argv[1][0] - '0');
+  return 0;
+}

compiler-rt/test/ubsan_minimal/TestCases/local_bounds.cpp

@@ -0,0 +1,28 @@
+// RUN: %clangxx -fsanitize=local-bounds %s -O3 -o %t && %run %t 1
+// RUN: %clangxx -fsanitize=local-bounds %s -O3 -o %t && not --crash %run %t 3
+
+// FIXME: it's always trap for now.
+
+#include <cstdlib>
+
+struct S {
+  int k;
+  int l;
+};
+
+__attribute__((noinline)) void init(S *s) {
+  __asm__ __volatile__("" : : "r"(s) : "memory");
+}
+
+__attribute__((noinline, no_sanitize("memory"))) int test(char i) {
+  S a;
+  init(&a);
+  S b;
+  init(&b);
+  return ((int *)(&a))[i];
+}
+
+int main(int argc, char **argv) {
+  test(argv[1][0] - '0');
+  return 0;
+}