9 files changed, 201 insertions, 0 deletions
diff --git a/test/shadowcallstack/CMakeLists.txt b/test/shadowcallstack/CMakeLists.txt
new file mode 100644
index 000000000000..ab2b18819d49
--- /dev/null
+++ b/test/shadowcallstack/CMakeLists.txt
@@ -0,0 +1,21 @@
+set(TEST_ARCH ${SHADOWCALLSTACK_SUPPORTED_ARCH})
+
+set(SHADOWCALLSTACK_LIT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+set(SHADOWCALLSTACK_LIT_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
+
+set(SHADOWCALLSTACK_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
+
+foreach(arch ${SHADOWCALLSTACK_SUPPORTED_ARCH})
+  set(SANITIZER_COMMON_TEST_TARGET_ARCH ${arch})
+  get_test_cc_for_arch(${arch}
+    SHADOWSTACK_TEST_TARGET_CC SHADOWSTACK_TEST_TARGET_CFLAGS)
+  configure_lit_site_cfg(
+    ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
+    ${CMAKE_CURRENT_BINARY_DIR}/${arch}/lit.site.cfg)
+  list(APPEND SHADOWCALLSTACK_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/${arch})
+endforeach()
+
+add_lit_testsuite(check-shadowcallstack "Running the ShadowCallStack tests"
+  ${SHADOWCALLSTACK_TESTSUITES}
+  DEPENDS ${SANITIZER_COMMON_LIT_TEST_DEPS})
+set_target_properties(check-shadowcallstack PROPERTIES FOLDER "Compiler-RT Misc")
diff --git a/test/shadowcallstack/init.c b/test/shadowcallstack/init.c
new file mode 100644
index 000000000000..a406e1b140fc
--- /dev/null
+++ b/test/shadowcallstack/init.c
@@ -0,0 +1,12 @@
+// RUN: %clang_scs %s -o %t
+// RUN: %run %t
+
+// Basic smoke test for the runtime
+
+#include "libc_support.h"
+#include "minimal_runtime.h"
+
+int scs_main(void) {
+  scs_fputs_stdout("In main.\n");
+  return 0;
+}
diff --git a/test/shadowcallstack/libc_support.h b/test/shadowcallstack/libc_support.h
new file mode 100644
index 000000000000..5d89aab645a9
--- /dev/null
+++ b/test/shadowcallstack/libc_support.h
@@ -0,0 +1,41 @@
+// This header provides replacements for certain libc functions. It is necessary
+// in order to safely run the tests on aarch64, because the system libc might
+// not have been compiled with -ffixed-x18.
+
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#ifdef __aarch64__
+
+size_t scs_strlen(const char *p) {
+  size_t retval = 0;
+  while (*p++)
+    retval++;
+  return retval;
+}
+
+// We mark this function as noinline to make sure that its callers do not
+// become leaf functions as a result of inlining. This is because we want to
+// make sure that we generate the correct code for non-leaf functions.
+
+__attribute__((noinline)) void scs_fputs_stdout(const char *p) {
+  __asm__ __volatile__(
+      "mov x0, #1\n"  // stdout
+      "mov x1, %0\n"
+      "mov x2, %1\n"
+      "mov x8, #64\n"  // write
+      "svc #0\n" ::"r"(p),
+      "r"(scs_strlen(p))
+      : "x0", "x1", "x2", "x8");
+}
+
+#else
+
+__attribute__((noinline)) void scs_fputs_stdout(const char *p) {
+  fputs(p, stdout);
+}
+
+#endif
diff --git a/test/shadowcallstack/lit.cfg b/test/shadowcallstack/lit.cfg
new file mode 100644
index 000000000000..313cd2b8eff3
--- /dev/null
+++ b/test/shadowcallstack/lit.cfg
@@ -0,0 +1,23 @@
+# -*- Python -*-
+
+import os
+
+# Setup config name.
+config.name = 'ShadowCallStack'
+
+# Setup source root.
+config.test_source_root = os.path.dirname(__file__)
+
+# Test suffixes.
+config.suffixes = ['.c', '.cc', '.cpp', '.m', '.mm', '.ll', '.test']
+
+# Add clang substitutions.
+config.substitutions.append( ("%clang_noscs ", config.clang + ' -O0 -fno-sanitize=shadow-call-stack ' + config.target_cflags + ' ') )
+
+scs_arch_cflags = config.target_cflags
+if config.target_arch == 'aarch64':
+  scs_arch_cflags += ' -ffixed-x18 '
+config.substitutions.append( ("%clang_scs ", config.clang + ' -O0 -fsanitize=shadow-call-stack ' + scs_arch_cflags + ' ') )
+
+if config.host_os not in ['Linux'] or config.target_arch not in ['x86_64', 'aarch64']:
+   config.unsupported = True
diff --git a/test/shadowcallstack/lit.site.cfg.in b/test/shadowcallstack/lit.site.cfg.in
new file mode 100644
index 000000000000..aa8913e84cb8
--- /dev/null
+++ b/test/shadowcallstack/lit.site.cfg.in
@@ -0,0 +1,12 @@
+@LIT_SITE_CFG_IN_HEADER@
+
+# Tool-specific config options.
+config.name_suffix = "@SHADOWCALLSTACK_TEST_CONFIG_SUFFIX@"
+config.target_cflags = "@SHADOWCALLSTACK_TEST_TARGET_CFLAGS@"
+config.target_arch = "@SHADOWCALLSTACK_TEST_TARGET_ARCH@"
+
+# Load common config for all compiler-rt lit tests.
+lit_config.load_config(config, "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")
+
+# Load tool-specific config that would do the real work.
+lit_config.load_config(config, "@SHADOWCALLSTACK_LIT_SOURCE_DIR@/lit.cfg")
diff --git a/test/shadowcallstack/minimal_runtime.h b/test/shadowcallstack/minimal_runtime.h
new file mode 100644
index 000000000000..f36fa5a7d245
--- /dev/null
+++ b/test/shadowcallstack/minimal_runtime.h
@@ -0,0 +1,43 @@
+// A shadow call stack runtime is not yet included with compiler-rt, provide a
+// minimal runtime to allocate a shadow call stack and assign an
+// architecture-specific register to point at it.
+
+#pragma once
+
+#ifdef __x86_64__
+#include <asm/prctl.h>
+int arch_prctl(int code, void *addr);
+#endif
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+
+#include "libc_support.h"
+
+__attribute__((no_sanitize("shadow-call-stack")))
+static void __shadowcallstack_init() {
+  void *stack = mmap(NULL, 8192, PROT_READ | PROT_WRITE,
+                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (stack == MAP_FAILED)
+    abort();
+
+#if defined(__x86_64__)
+  if (arch_prctl(ARCH_SET_GS, stack))
+    abort();
+#elif defined(__aarch64__)
+  __asm__ __volatile__("mov x18, %0" ::"r"(stack));
+#else
+#error Unsupported platform
+#endif
+}
+
+int scs_main(void);
+
+__attribute__((no_sanitize("shadow-call-stack"))) int main(void) {
+  __shadowcallstack_init();
+
+  // We can't simply return scs_main() because scs_main might have corrupted our
+  // return address for testing purposes (see overflow.c), so we need to exit
+  // ourselves.
+  exit(scs_main());
+}
diff --git a/test/shadowcallstack/overflow-aarch64.c b/test/shadowcallstack/overflow-aarch64.c
new file mode 100644
index 000000000000..8da798164fe7
--- /dev/null
+++ b/test/shadowcallstack/overflow-aarch64.c
@@ -0,0 +1,5 @@
+// See overflow.c for a description.
+
+// REQUIRES: aarch64-target-arch
+// RUN: %clang_scs %S/overflow.c -o %t -DITERATIONS=12
+// RUN: %run %t | FileCheck %S/overflow.c
diff --git a/test/shadowcallstack/overflow-x86_64.c b/test/shadowcallstack/overflow-x86_64.c
new file mode 100644
index 000000000000..38bb13a969a3
--- /dev/null
+++ b/test/shadowcallstack/overflow-x86_64.c
@@ -0,0 +1,5 @@
+// See overflow.c for a description.
+
+// REQUIRES: x86_64-target-arch
+// RUN: %clang_scs %S/overflow.c -o %t -DITERATIONS=12
+// RUN: not --crash %run %t
diff --git a/test/shadowcallstack/overflow.c b/test/shadowcallstack/overflow.c
new file mode 100644
index 000000000000..8c3d50c5917f
--- /dev/null
+++ b/test/shadowcallstack/overflow.c
@@ -0,0 +1,39 @@
+// Test that a stack overflow fails as expected
+
+// RUN: %clang_noscs %s -o %t -DITERATIONS=3
+// RUN: %run %t | FileCheck %s
+// RUN: %clang_noscs %s -o %t -DITERATIONS=12
+// RUN: %run %t | FileCheck -check-prefix=OVERFLOW_SUCCESS %s
+
+// RUN: %clang_scs %s -o %t -DITERATIONS=3
+// RUN: %run %t | FileCheck %s
+
+// The behavioral check for SCS + overflow lives in the tests overflow-x86_64.c
+// and overflow-aarch64.c. This is because the expected behavior is different
+// between the two platforms. On x86_64 we crash because the comparison between
+// the shadow call stack and the regular stack fails. On aarch64 there is no
+// comparison, we just load the return address from the shadow call stack. So we
+// just expect not to see the output from print_and_exit.
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "minimal_runtime.h"
+
+void print_and_exit(void) {
+// CHECK-NOT: Stack overflow successful.
+// OVERFLOW_SUCCESS: Stack overflow successful.
+  scs_fputs_stdout("Stack overflow successful.\n");
+  exit(0);
+}
+
+int scs_main(void)
+{
+  void *addrs[4];
+  for (int i = 0; i < ITERATIONS; i++)
+    addrs[i] = &print_and_exit;
+
+  scs_fputs_stdout("Returning.\n");
+
+  return 0;
+}