[ASan] support for running OS-specific tests using lit, port clone_test as an example

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@161864 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/asan/lit_tests/Linux/clone_test.cc b/lib/asan/lit_tests/Linux/clone_test.cc
new file mode 100644
index 0000000..ece27b1
--- /dev/null
+++ b/lib/asan/lit_tests/Linux/clone_test.cc
@@ -0,0 +1,33 @@
+// Regression test for:
+// http://code.google.com/p/address-sanitizer/issues/detail?id=37
+
+// RUN: %clang_asan -O2 %s -o %t
+// RUN: %t | FileCheck %s
+
+#include <stdio.h>
+#include <sched.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int Child(void *arg) {
+  char x[32] = {0};  // Stack gets poisoned.
+  printf("Child:  %p\n", x);
+  _exit(1);  // NoReturn, stack will remain unpoisoned unless we do something.
+}
+
+int main(int argc, char **argv) {
+  const int kStackSize = 1 << 20;
+  char child_stack[kStackSize + 1];
+  char *sp = child_stack + kStackSize;  // Stack grows down.
+  printf("Parent: %p\n", sp);
+  pid_t clone_pid = clone(Child, sp, CLONE_FILES | CLONE_VM, NULL, 0, 0, 0);
+  waitpid(clone_pid, NULL, 0);
+  for (int i = 0; i < kStackSize; i++)
+    child_stack[i] = i;
+  int ret = child_stack[argc - 1];
+  printf("PASSED\n");
+  // CHECK: PASSED
+  return ret;
+}
diff --git a/lib/asan/lit_tests/Linux/lit.local.cfg b/lib/asan/lit_tests/Linux/lit.local.cfg
new file mode 100644
index 0000000..57271b8
--- /dev/null
+++ b/lib/asan/lit_tests/Linux/lit.local.cfg
@@ -0,0 +1,9 @@
+def getRoot(config):
+  if not config.parent:
+    return config
+  return getRoot(config.parent)
+
+root = getRoot(config)
+
+if root.host_os not in ['Linux']:
+  config.unsupported = True
diff --git a/lib/asan/lit_tests/lit.site.cfg.in b/lib/asan/lit_tests/lit.site.cfg.in
index f438570..89956e6 100644
--- a/lib/asan/lit_tests/lit.site.cfg.in
+++ b/lib/asan/lit_tests/lit.site.cfg.in
@@ -2,6 +2,7 @@
 # Do not edit!
 
 config.target_triple = "@TARGET_TRIPLE@"
+config.host_os = "@HOST_OS@"
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.clang = "@LLVM_BINARY_DIR@/bin/clang"