Don't call rust_begin_unwind

builtins-test-intrinsics/Cargo.toml

@@ -8,5 +8,9 @@ publish = false
 compiler_builtins = { path = "../", features = ["compiler-builtins"]}
 panic-handler = { path = '../crates/panic-handler' }
 
+[target.'cfg(target_family = "windows")'.dependencies]
+# `#![no_std]` on Windows needs `string.h` routines.
+compiler_builtins = { path = "../", features = ["compiler-builtins", "mem"]}
+
 [features]
 c = ["compiler_builtins/c"]

builtins-test-intrinsics/build.rs

@@ -8,4 +8,9 @@ fn main() {
     let target = builtins_configure::Target::from_env();
     builtins_configure::configure_f16_f128(&target);
     builtins_configure::configure_aliases(&target);
+
+    if target.os == "windows" {
+        // Needed for using the `mainCRTStartup` entrypoint
+        println!("cargo::rustc-link-arg=/subsystem:console");
+    }
 }

builtins-test-intrinsics/src/main.rs

@@ -13,6 +13,9 @@
 #![no_std]
 #![no_main]
 
+// Ensure this repo's version of `compiler_builtins` gets used, rather than what gets injected from
+// the sysroot.
+extern crate compiler_builtins;
 extern crate panic_handler;
 
 #[cfg(all(not(thumb), not(windows), not(target_arch = "wasm32")))]
@@ -626,12 +629,12 @@ fn run() {
 
     something_with_a_dtor(&|| assert_eq!(bb(1), 1));
 
-    extern "C" {
-        fn rust_begin_unwind(x: usize);
-    }
-
-    unsafe {
-        rust_begin_unwind(0);
+    // Ensure panic machinery gets linked, but still allow this to run to completion.
+    // FIXME(windows): we should have this on Windows too but it requires a lot more
+    // missing symbols.
+    #[cfg(not(windows))]
+    if bb(false) {
+        panic!();
     }
 }
 
@@ -648,15 +651,23 @@ fn something_with_a_dtor(f: &dyn Fn()) {
 }
 
 #[no_mangle]
-#[cfg(not(thumb))]
-fn main(_argc: core::ffi::c_int, _argv: *const *const u8) -> core::ffi::c_int {
+#[cfg(not(any(thumb, windows)))]
+extern "C" fn main(_argc: core::ffi::c_int, _argv: *const *const u8) -> core::ffi::c_int {
+    run();
+    0
+}
+
+#[no_mangle]
+#[cfg(windows)]
+#[allow(non_snake_case)]
+extern "C" fn mainCRTStartup() -> core::ffi::c_int {
     run();
     0
 }
 
 #[no_mangle]
 #[cfg(thumb)]
-pub fn _start() -> ! {
+extern "C" fn _start() -> ! {
     run();
     loop {}
 }
@@ -673,15 +684,21 @@ pub fn __aeabi_unwind_cpp_pr0() {}
 #[no_mangle]
 pub fn __aeabi_unwind_cpp_pr1() {}
 
-#[cfg(not(any(windows, target_os = "cygwin")))]
-#[allow(non_snake_case)]
 #[no_mangle]
+#[allow(non_snake_case)]
+#[cfg(not(any(windows, target_os = "cygwin")))]
 pub fn _Unwind_Resume() {}
 
-#[cfg(not(any(windows, target_os = "cygwin")))]
-#[lang = "eh_personality"]
 #[no_mangle]
-pub extern "C" fn eh_personality() {}
+#[lang = "eh_personality"]
+#[cfg(not(any(windows, target_os = "cygwin")))]
+pub extern "system" fn eh_personality() {}
+
+#[cfg(windows)]
+#[unsafe(no_mangle)]
+extern "system" fn __CxxFrameHandler3() -> ! {
+    unimplemented!()
+}
 
 #[cfg(any(all(windows, target_env = "gnu"), target_os = "cygwin"))]
 mod mingw_unwinding {

ci/run.sh

@@ -120,22 +120,28 @@ done
 
 rm -f "${rlib_paths[@]}"
 
-build_intrinsics_test() {
-    cargo build --target "$target" -v --package builtins-test-intrinsics "$@"
+run_intrinsics_test() {
+    # FIXME(windows): We should be able to run this test on Windows too, but it
+    # seems to run into a lot more missing symbols.
+    if [[ "${NO_STD:-}" = "1" || "$target" == *"windows" ]]; then
+        cmd=build
+    else
+        cmd=run
+    fi
+
+    cargo "$cmd" --target "$target" -v --package builtins-test-intrinsics "$@"
 }
 
 # Verify that we haven't dropped any intrinsics/symbols
-build_intrinsics_test
-build_intrinsics_test --release
-build_intrinsics_test --features c
-build_intrinsics_test --features c --release
+run_intrinsics_test
+run_intrinsics_test --release
+run_intrinsics_test --features c
+run_intrinsics_test --features c --release
 
 # Verify that there are no undefined symbols to `panic` within our
 # implementations
-CARGO_PROFILE_DEV_LTO=true \
-    cargo build --target "$target" --package builtins-test-intrinsics
-CARGO_PROFILE_RELEASE_LTO=true \
-    cargo build --target "$target" --package builtins-test-intrinsics --release
+CARGO_PROFILE_DEV_LTO=true run_intrinsics_test
+CARGO_PROFILE_RELEASE_LTO=true run_intrinsics_test --release
 
 # Ensure no references to any symbols from core
 update_rlib_paths