Auto merge of #3319 - bjorn3:some_more_shims, r=RalfJung
Directly implement native exception raise methods in miri This implements the `_Unwind_RaiseException` function used on pretty much every unix system for starting unwinding. This allows removing the miri special case from libpanic_unwind for unix. Windows still needs `miri_start_unwind` as SEH unwinding isn't supported by miri. Unlike DWARF unwinding, SEH preserves all stack frames until right after the do_catch function has executed. Because of this panic_unwind stack allocates the exception object. Miri can't currently model unwinding without destroying stack frames and as such will report a use-after-free of the exception object.
This commit is contained in:
commit
85ed056888
@ -145,7 +145,7 @@ case $HOST_TARGET in
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TEST_TARGET=s390x-unknown-linux-gnu run_tests # big-endian architecture of choice
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# Partially supported targets (tier 2)
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BASIC="empty_main integer vec string btreemap hello hashmap heap_alloc align" # ensures we have the basics: stdout/stderr, system allocator, randomness (for HashMap initialization)
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UNIX="panic/panic concurrency/simple atomic libc-mem libc-misc libc-random env num_cpus" # the things that are very similar across all Unixes, and hence easily supported there
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UNIX="panic/panic panic/unwind concurrency/simple atomic libc-mem libc-misc libc-random env num_cpus" # the things that are very similar across all Unixes, and hence easily supported there
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TEST_TARGET=x86_64-unknown-freebsd run_tests_minimal $BASIC $UNIX threadname libc-time fs
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TEST_TARGET=i686-unknown-freebsd run_tests_minimal $BASIC $UNIX threadname libc-time fs
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TEST_TARGET=x86_64-unknown-illumos run_tests_minimal $BASIC $UNIX pthread-sync
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@ -116,7 +116,7 @@ fn fence_ord(ord: &str) -> AtomicFenceOrd {
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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@ -26,7 +26,7 @@ fn call_intrinsic(
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args: &[OpTy<'tcx, Provenance>],
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dest: &MPlaceTy<'tcx, Provenance>,
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ret: Option<mir::BasicBlock>,
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_unwind: mir::UnwindAction,
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unwind: mir::UnwindAction,
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) -> InterpResult<'tcx, Option<ty::Instance<'tcx>>> {
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let this = self.eval_context_mut();
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@ -62,11 +62,16 @@ fn call_intrinsic(
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args: instance.args,
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}))
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}
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EmulateItemResult::NeedsJumping => {
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EmulateItemResult::NeedsReturn => {
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trace!("{:?}", this.dump_place(&dest.clone().into()));
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this.return_to_block(ret)?;
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Ok(None)
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}
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EmulateItemResult::NeedsUnwind => {
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// Jump to the unwind block to begin unwinding.
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this.unwind_to_block(unwind)?;
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Ok(None)
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}
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EmulateItemResult::AlreadyJumped => Ok(None),
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}
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}
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@ -441,6 +446,6 @@ fn emulate_intrinsic_by_name(
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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@ -746,7 +746,7 @@ enum Op {
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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fn fminmax_op(
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@ -87,7 +87,7 @@ fn emulate_allocator(
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}
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AllocatorKind::Default => {
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default(this)?;
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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}
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@ -82,11 +82,15 @@ fn emulate_foreign_item(
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}
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// The rest either implements the logic, or falls back to `lookup_exported_symbol`.
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match this.emulate_foreign_item_inner(link_name, abi, args, dest, unwind)? {
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EmulateItemResult::NeedsJumping => {
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match this.emulate_foreign_item_inner(link_name, abi, args, dest)? {
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EmulateItemResult::NeedsReturn => {
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trace!("{:?}", this.dump_place(&dest.clone().into()));
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this.return_to_block(ret)?;
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}
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EmulateItemResult::NeedsUnwind => {
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// Jump to the unwind block to begin unwinding.
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this.unwind_to_block(unwind)?;
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}
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EmulateItemResult::AlreadyJumped => (),
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EmulateItemResult::NotSupported => {
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if let Some(body) = this.lookup_exported_symbol(link_name)? {
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@ -206,7 +210,6 @@ fn emulate_foreign_item_inner(
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abi: Abi,
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args: &[OpTy<'tcx, Provenance>],
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dest: &MPlaceTy<'tcx, Provenance>,
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unwind: mir::UnwindAction,
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) -> InterpResult<'tcx, EmulateItemResult> {
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let this = self.eval_context_mut();
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@ -218,7 +221,7 @@ fn emulate_foreign_item_inner(
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// by the specified `.so` file; we should continue and check if it corresponds to
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// a provided shim.
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if this.call_native_fn(link_name, dest, args)? {
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return Ok(EmulateItemResult::NeedsJumping);
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return Ok(EmulateItemResult::NeedsReturn);
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}
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}
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@ -263,9 +266,9 @@ fn emulate_foreign_item_inner(
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match link_name.as_str() {
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// Miri-specific extern functions
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"miri_start_unwind" => {
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// `check_shim` happens inside `handle_miri_start_unwind`.
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this.handle_miri_start_unwind(abi, link_name, args, unwind)?;
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return Ok(EmulateItemResult::AlreadyJumped);
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let [payload] = this.check_shim(abi, Abi::Rust, link_name, args)?;
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this.handle_miri_start_unwind(payload)?;
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return Ok(EmulateItemResult::NeedsUnwind);
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}
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"miri_run_provenance_gc" => {
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let [] = this.check_shim(abi, Abi::Rust, link_name, args)?;
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@ -480,7 +483,7 @@ fn emulate_foreign_item_inner(
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"__rust_alloc" => return this.emulate_allocator(default),
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"miri_alloc" => {
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default(this)?;
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return Ok(EmulateItemResult::NeedsJumping);
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return Ok(EmulateItemResult::NeedsReturn);
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}
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_ => unreachable!(),
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}
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@ -540,7 +543,7 @@ fn emulate_foreign_item_inner(
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}
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"miri_dealloc" => {
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default(this)?;
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return Ok(EmulateItemResult::NeedsJumping);
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return Ok(EmulateItemResult::NeedsReturn);
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}
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_ => unreachable!(),
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}
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@ -961,6 +964,6 @@ fn emulate_foreign_item_inner(
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};
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// We only fall through to here if we did *not* hit the `_` arm above,
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// i.e., if we actually emulated the function with one of the shims.
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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@ -22,8 +22,10 @@
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/// What needs to be done after emulating an item (a shim or an intrinsic) is done.
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pub enum EmulateItemResult {
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/// The caller is expected to jump to the return block.
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NeedsJumping,
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/// Jumping has already been taken care of.
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NeedsReturn,
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/// The caller is expected to jump to the unwind block.
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NeedsUnwind,
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/// Jumping to the next block has already been taken care of.
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AlreadyJumped,
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/// The item is not supported.
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NotSupported,
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@ -13,7 +13,6 @@
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use rustc_ast::Mutability;
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use rustc_middle::{mir, ty};
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use rustc_span::Symbol;
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use rustc_target::spec::abi::Abi;
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use rustc_target::spec::PanicStrategy;
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@ -46,25 +45,15 @@ impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir,
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pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
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/// Handles the special `miri_start_unwind` intrinsic, which is called
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/// by libpanic_unwind to delegate the actual unwinding process to Miri.
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fn handle_miri_start_unwind(
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&mut self,
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abi: Abi,
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link_name: Symbol,
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args: &[OpTy<'tcx, Provenance>],
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unwind: mir::UnwindAction,
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) -> InterpResult<'tcx> {
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fn handle_miri_start_unwind(&mut self, payload: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx> {
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let this = self.eval_context_mut();
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trace!("miri_start_unwind: {:?}", this.frame().instance);
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// Get the raw pointer stored in arg[0] (the panic payload).
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let [payload] = this.check_shim(abi, Abi::Rust, link_name, args)?;
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let payload = this.read_scalar(payload)?;
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let thread = this.active_thread_mut();
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thread.panic_payloads.push(payload);
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// Jump to the unwind block to begin unwinding.
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this.unwind_to_block(unwind)?;
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Ok(())
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}
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@ -27,6 +27,6 @@ fn emulate_foreign_item_inner(
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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@ -639,6 +639,31 @@ fn emulate_foreign_item_inner(
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this.gen_random(ptr, len)?;
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this.write_scalar(Scalar::from_target_usize(len, this), dest)?;
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}
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"_Unwind_RaiseException" => {
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// This is not formally part of POSIX, but it is very wide-spread on POSIX systems.
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// It was originally specified as part of the Itanium C++ ABI:
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// https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html#base-throw.
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// On Linux it is
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// documented as part of the LSB:
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// https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/baselib--unwind-raiseexception.html
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// Basically every other UNIX uses the exact same api though. Arm also references
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// back to the Itanium C++ ABI for the definition of `_Unwind_RaiseException` for
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// arm64:
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// https://github.com/ARM-software/abi-aa/blob/main/cppabi64/cppabi64.rst#toc-entry-35
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// For arm32 they did something custom, but similar enough that the same
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// `_Unwind_RaiseException` impl in miri should work:
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// https://github.com/ARM-software/abi-aa/blob/main/ehabi32/ehabi32.rst
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if !matches!(&*this.tcx.sess.target.os, "linux" | "freebsd" | "illumos" | "solaris" | "android" | "macos") {
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throw_unsup_format!(
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"`_Unwind_RaiseException` is not supported on {}",
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this.tcx.sess.target.os
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);
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}
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// This function looks and behaves excatly like miri_start_unwind.
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let [payload] = this.check_shim(abi, Abi::C { unwind: true }, link_name, args)?;
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this.handle_miri_start_unwind(payload)?;
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return Ok(EmulateItemResult::NeedsUnwind);
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}
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// Incomplete shims that we "stub out" just to get pre-main initialization code to work.
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// These shims are enabled only when the caller is in the standard library.
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@ -760,6 +785,6 @@ fn emulate_foreign_item_inner(
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}
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};
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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@ -86,6 +86,6 @@ fn emulate_foreign_item_inner(
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -203,6 +203,6 @@ fn emulate_foreign_item_inner(
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_ => return Ok(EmulateItemResult::NotSupported),
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};
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -177,6 +177,6 @@ fn emulate_foreign_item_inner(
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_ => return Ok(EmulateItemResult::NotSupported),
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};
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -45,6 +45,6 @@ fn emulate_foreign_item_inner(
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -35,6 +35,6 @@ fn emulate_foreign_item_inner(
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -762,6 +762,6 @@ fn emulate_foreign_item_inner(
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -127,7 +127,7 @@ fn emulate_x86_aesni_intrinsic(
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// with an external crate.
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -344,6 +344,6 @@ fn emulate_x86_avx_intrinsic(
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}
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -440,6 +440,6 @@ fn emulate_x86_avx2_intrinsic(
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}
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -144,7 +144,7 @@ fn emulate_x86_intrinsic(
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -212,6 +212,6 @@ fn emulate_x86_sse_intrinsic(
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}
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
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}
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}
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|
@ -388,6 +388,6 @@ fn emulate_x86_sse2_intrinsic(
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}
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_ => return Ok(EmulateItemResult::NotSupported),
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}
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Ok(EmulateItemResult::NeedsJumping)
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Ok(EmulateItemResult::NeedsReturn)
|
||||
}
|
||||
}
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|
@ -51,6 +51,6 @@ fn emulate_x86_sse3_intrinsic(
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}
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_ => return Ok(EmulateItemResult::NotSupported),
|
||||
}
|
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Ok(EmulateItemResult::NeedsJumping)
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||||
Ok(EmulateItemResult::NeedsReturn)
|
||||
}
|
||||
}
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||||
|
@ -176,6 +176,6 @@ fn emulate_x86_sse41_intrinsic(
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}
|
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_ => return Ok(EmulateItemResult::NotSupported),
|
||||
}
|
||||
Ok(EmulateItemResult::NeedsJumping)
|
||||
Ok(EmulateItemResult::NeedsReturn)
|
||||
}
|
||||
}
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||||
|
@ -137,6 +137,6 @@ fn emulate_x86_ssse3_intrinsic(
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}
|
||||
_ => return Ok(EmulateItemResult::NotSupported),
|
||||
}
|
||||
Ok(EmulateItemResult::NeedsJumping)
|
||||
Ok(EmulateItemResult::NeedsReturn)
|
||||
}
|
||||
}
|
||||
|
96
src/tools/miri/tests/pass/panic/unwind_dwarf.rs
Normal file
96
src/tools/miri/tests/pass/panic/unwind_dwarf.rs
Normal file
@ -0,0 +1,96 @@
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//@ignore-target-windows: Windows uses a different unwinding mechanism
|
||||
#![feature(core_intrinsics, panic_unwind, rustc_attrs)]
|
||||
#![allow(internal_features)]
|
||||
|
||||
//! Unwinding using `_Unwind_RaiseException`
|
||||
|
||||
extern crate unwind as uw;
|
||||
|
||||
use std::any::Any;
|
||||
use std::ptr;
|
||||
|
||||
#[repr(C)]
|
||||
struct Exception {
|
||||
_uwe: uw::_Unwind_Exception,
|
||||
cause: Box<dyn Any + Send>,
|
||||
}
|
||||
|
||||
pub fn panic(data: Box<dyn Any + Send>) -> u32 {
|
||||
extern "C" fn exception_cleanup(
|
||||
_unwind_code: uw::_Unwind_Reason_Code,
|
||||
_exception: *mut uw::_Unwind_Exception,
|
||||
) {
|
||||
std::process::abort();
|
||||
}
|
||||
|
||||
let exception = Box::new(Exception {
|
||||
_uwe: uw::_Unwind_Exception {
|
||||
exception_class: miri_exception_class(),
|
||||
exception_cleanup: Some(exception_cleanup),
|
||||
private: [core::ptr::null(); uw::unwinder_private_data_size],
|
||||
},
|
||||
cause: data,
|
||||
});
|
||||
let exception_param = Box::into_raw(exception) as *mut uw::_Unwind_Exception;
|
||||
return unsafe { uw::_Unwind_RaiseException(exception_param) as u32 };
|
||||
}
|
||||
|
||||
pub unsafe fn rust_panic_cleanup(ptr: *mut u8) -> Box<dyn Any + Send> {
|
||||
let exception = ptr as *mut uw::_Unwind_Exception;
|
||||
if (*exception).exception_class != miri_exception_class() {
|
||||
std::process::abort();
|
||||
}
|
||||
|
||||
let exception = exception.cast::<Exception>();
|
||||
|
||||
let exception = Box::from_raw(exception as *mut Exception);
|
||||
exception.cause
|
||||
}
|
||||
|
||||
fn miri_exception_class() -> uw::_Unwind_Exception_Class {
|
||||
// M O Z \0 M I R I -- vendor, language
|
||||
// (Miri's own exception class is just used for testing)
|
||||
0x4d4f5a_00_4d495249
|
||||
}
|
||||
|
||||
pub fn catch_unwind<R, F: FnOnce() -> R>(f: F) -> Result<R, Box<dyn Any + Send>> {
|
||||
struct Data<F, R> {
|
||||
f: Option<F>,
|
||||
r: Option<R>,
|
||||
p: Option<Box<dyn Any + Send>>,
|
||||
}
|
||||
|
||||
let mut data = Data { f: Some(f), r: None, p: None };
|
||||
|
||||
let data_ptr = ptr::addr_of_mut!(data) as *mut u8;
|
||||
unsafe {
|
||||
return if std::intrinsics::catch_unwind(do_call::<F, R>, data_ptr, do_catch::<F, R>) == 0 {
|
||||
Ok(data.r.take().unwrap())
|
||||
} else {
|
||||
Err(data.p.take().unwrap())
|
||||
};
|
||||
}
|
||||
|
||||
fn do_call<F: FnOnce() -> R, R>(data: *mut u8) {
|
||||
unsafe {
|
||||
let data = &mut *data.cast::<Data<F, R>>();
|
||||
let f = data.f.take().unwrap();
|
||||
data.r = Some(f());
|
||||
}
|
||||
}
|
||||
|
||||
#[rustc_nounwind]
|
||||
fn do_catch<F: FnOnce() -> R, R>(data: *mut u8, payload: *mut u8) {
|
||||
unsafe {
|
||||
let obj = rust_panic_cleanup(payload);
|
||||
(*data.cast::<Data<F, R>>()).p = Some(obj);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {
|
||||
assert_eq!(
|
||||
catch_unwind(|| panic(Box::new(42))).unwrap_err().downcast::<i32>().unwrap(),
|
||||
Box::new(42)
|
||||
);
|
||||
}
|
Loading…
Reference in New Issue
Block a user