Fix Checked C tests on Mac OS (#502)

This change updates the Checked C tests so that they run properly on Apple ARM64 hardware running a recent version of MacOS. The changes consist of:

- Using SIGTRAP signal handlers catch runtime checking failures instead of SIGILL.
- Only run Linux-specific header file tests on Linux.
- Add a bounds-safe interface specific to MacOS so that errno work properly in a checked scope.

Testing:
check-checkedc passes on Windows x86 and MacOS 13.4.1

include/errno_checked.h

@@ -24,7 +24,11 @@
 #if defined(_WIN32) || defined(_WIN64)
 __declspec(dllimport) int* __cdecl _errno(void) : itype(_Ptr<int>);
 #elif defined(__APPLE__)
+#if defined(__aarch64__)
+extern int * __error(void) : itype(_Ptr<int>);
+#else
 extern int* __errno_location(void) : itype(_Ptr<int>);
+#endif
 #else
 extern int* __errno_location(void) : itype(_Ptr<int>) __THROW __attribute_const__;
 #endif

tests/checked_headers/redeclare_libs_explicit_linux.c

@@ -1,4 +1,4 @@
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: !linux
 //
 // Test include files for all combinations of Checked C enabled/disabled,
 // and implicit inclusion of checked headers enabled/disabled. By default, both

tests/checked_headers/redeclare_libs_implicit_linux.c

@@ -1,4 +1,4 @@
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: !linux
 //
 // Test include files for all combinations of Checked C enabled/disabled,
 // and implicit inclusion of checked headers enabled/disabled. By default, both

tests/checked_headers/redeclare_libs_mixed_linux.c

@@ -1,4 +1,4 @@
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: !linux
 //
 // Test include files for all combinations of Checked C enabled/disabled,
 // and implicit inclusion of checked headers enabled/disabled. By default, both

tests/dynamic_checking/bounds/array-bounds-decls.c

@@ -62,9 +62,12 @@ int write_fail(int testnum, int pos, ptr<struct S1> s, ptr<struct S3> s3);
 int main(int argc, array_ptr<char*> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRIP when a bounds check fails,
+  // dpending on the target OS.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/bounds/bounds-safe-interfaces.c

@@ -96,9 +96,12 @@ void read_test(int failure_point, int *p : count(p_len), int p_len,
 int main(int argc, array_ptr<char*> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/bounds/deref.c

@@ -88,9 +88,12 @@ void handle_error(int err) {
 int main(int argc, array_ptr<char*> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/bounds/deref_dot_member_expr.c

@@ -137,9 +137,12 @@ void handle_error(int err) {
 int main(int argc, array_ptr<char*> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/bounds/nullterm_pointers.c

@@ -73,9 +73,12 @@ void handle_error(int err) {
 int main(int argc, array_ptr<char*> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/bounds/predefined_literals.c

@@ -40,7 +40,13 @@ void fail1(int x) {
 }
 
 int main(int argc, array_ptr<char*> argv : count(argc)) {
+  // Set up the handler for a failing bounds check.  Currently the Checked C
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/bounds/subscript.c

@@ -198,9 +198,12 @@ void handle_error(int err) {
 int main(int argc, array_ptr<char*> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // Unfortunately, using atoi everywhere below isn't super
   // great, as it will return 0 if it can't parse, which is a valid,

tests/dynamic_checking/bounds/subscript_call_expr.c

@@ -740,9 +740,12 @@ void test_md_dependent_bounds(int argc, array_ptr<nt_array_ptr<char>> argv : cou
 int main(int argc, array_ptr<nt_array_ptr<char>> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // Unfortunately, using atoi everywhere below isn't super
   // great, as it will return 0 if it can't parse, which is a valid,

tests/dynamic_checking/bounds/subscript_dot_member_expr.c

@@ -123,9 +123,12 @@ void handle_error(int err) {
 int main(int argc, array_ptr<char*> argv : count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/dynamic-bounds-cast-check.c

@@ -44,9 +44,12 @@ void handle_error(int err) {
 int main(int argc, char**_Array argv  _Count(argc)) {
 
   // Set up the handler for a failing bounds check.  Currently the Checked C
-  // clang implementation raises a SIGILL when a bounds check fails.  This
-  // may change in the future.
+  // clang implementation raises a SIGILL or SIGTRAP when a bounds check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.

tests/dynamic_checking/dynamic_check/arith-fail.c

@@ -23,9 +23,13 @@ void handle_error(int err) {
 }
 
 int main(void) {
-  // Currently the Checked C clang implementation raises a SIGILL when a
-  // dynamic check fails.  This may change in the future.
+  // Set up the handler for a failing dynamic check.  Currently the Checked C
+  // clang implementation raises a SIGILL or SIGTRAP when a dynamic check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   f1(50);
 

tests/dynamic_checking/dynamic_check/simple-fail.c

@@ -2,6 +2,7 @@
 //
 // The following lines are for the LLVM test harness:
 //
+// RUN %clang -###
 // RUN: %clang -Xclang -verify -o %t.exe %s %checkedc_target_flags
 // RUN: %checkedc_rununder %t.exe
 
@@ -15,9 +16,13 @@ void handle_error(int err) {
 }
 
 int main(void) {
-  // Currently the Checked C clang implementation raises a SIGILL when a
-  // dynamic check fails.  This may change in the future.
+  // Set up the handler for a failing dynamic check.  Currently the Checked C
+  // clang implementation raises a SIGILL or SIGTRAP when a dynamic check fails,
+  // depending on the target platform.  This may change in the future.
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This is expected fail at runtime. It is simple enough for clang to issue a warning
   dynamic_check(false); // expected-warning {{dynamic check will always fail}}

tests/dynamic_checking/null_ptr_checks/ptr-arith.c

@@ -128,6 +128,9 @@ void pass3() {
 
 int main(int argc, array_ptr<char *> argv : count(argc)) {
   signal(SIGILL, handle_error);
+#if defined(__APPLE__) && defined(__aarch64__)
+  signal(SIGTRAP, handle_error);
+#endif
 
   // This makes sure output is not buffered for when
   // we hit errors.