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move panic intrinsic codegen to helper function

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This commit is contained in:
Ralf Jung 2020-02-29 09:40:40 +01:00
parent bfe593e03a
commit 7c84e451d5
1 changed files with 92 additions and 66 deletions
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158
src/librustc_codegen_ssa/mir/block.rs
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@ -434,6 +434,89 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
helper.do_call(self, &mut bx, fn_abi, llfn, &args, None, cleanup);
}
/// Returns `true` if this is indeed a panic intrinsic and codegen is done.
fn codegen_panic_intrinsic(
&mut self,
helper: &TerminatorCodegenHelper<'tcx>,
bx: &mut Bx,
intrinsic: Option<&str>,
instance: Option<Instance<'tcx>>,
span: Span,
destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
cleanup: Option<mir::BasicBlock>,
) -> bool {
// Emit a panic or a no-op for `panic_if_uninhabited`.
// These are intrinsics that compile to panics so that we can get a message
// which mentions the offending type, even from a const context.
#[derive(Debug, PartialEq)]
enum PanicIntrinsic {
IfUninhabited,
IfZeroInvalid,
IfAnyInvalid,
};
let panic_intrinsic = intrinsic.and_then(|i| match i {
// FIXME: Move to symbols instead of strings.
"panic_if_uninhabited" => Some(PanicIntrinsic::IfUninhabited),
"panic_if_zero_invalid" => Some(PanicIntrinsic::IfZeroInvalid),
"panic_if_any_invalid" => Some(PanicIntrinsic::IfAnyInvalid),
_ => None,
});
if let Some(intrinsic) = panic_intrinsic {
use PanicIntrinsic::*;
let ty = instance.unwrap().substs.type_at(0);
let layout = bx.layout_of(ty);
let do_panic = match intrinsic {
IfUninhabited => layout.abi.is_uninhabited(),
// We unwrap as the error type is `!`.
IfZeroInvalid => !layout.might_permit_raw_init(bx, /*zero:*/ true).unwrap(),
// We unwrap as the error type is `!`.
IfAnyInvalid => !layout.might_permit_raw_init(bx, /*zero:*/ false).unwrap(),
};
if do_panic {
let msg_str = if layout.abi.is_uninhabited() {
// Use this error even for the other intrinsics as it is more precise.
format!("attempted to instantiate uninhabited type `{}`", ty)
} else if intrinsic == IfZeroInvalid {
format!("attempted to zero-initialize type `{}`, which is invalid", ty)
} else {
format!("attempted to leave type `{}` uninitialized, which is invalid", ty)
};
let msg = bx.const_str(Symbol::intern(&msg_str));
let location = self.get_caller_location(bx, span).immediate();
// Obtain the panic entry point.
// FIXME: dedup this with `codegen_assert_terminator` above.
let def_id =
common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem);
let instance = ty::Instance::mono(bx.tcx(), def_id);
let fn_abi = FnAbi::of_instance(bx, instance, &[]);
let llfn = bx.get_fn_addr(instance);
if let Some((_, target)) = destination.as_ref() {
helper.maybe_sideeffect(self.mir, bx, &[*target]);
}
// Codegen the actual panic invoke/call.
helper.do_call(
self,
bx,
fn_abi,
llfn,
&[msg.0, msg.1, location],
destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)),
cleanup,
);
} else {
// a NOP
let target = destination.as_ref().unwrap().1;
helper.maybe_sideeffect(self.mir, bx, &[target]);
helper.funclet_br(self, bx, target)
}
true
} else {
false
}
}
fn codegen_call_terminator(
&mut self,
helper: TerminatorCodegenHelper<'tcx>,
@ -520,72 +603,15 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
bug!("`miri_start_panic` should never end up in compiled code");
}
// Emit a panic or a no-op for `panic_if_uninhabited`.
// These are intrinsics that compile to panics so that we can get a message
// which mentions the offending type, even from a const context.
#[derive(Debug, PartialEq)]
enum PanicIntrinsic {
IfUninhabited,
IfZeroInvalid,
IfAnyInvalid,
};
let panic_intrinsic = intrinsic.and_then(|i| match i {
// FIXME: Move to symbols instead of strings.
"panic_if_uninhabited" => Some(PanicIntrinsic::IfUninhabited),
"panic_if_zero_invalid" => Some(PanicIntrinsic::IfZeroInvalid),
"panic_if_any_invalid" => Some(PanicIntrinsic::IfAnyInvalid),
_ => None,
});
if let Some(intrinsic) = panic_intrinsic {
use PanicIntrinsic::*;
let ty = instance.unwrap().substs.type_at(0);
let layout = bx.layout_of(ty);
let do_panic = match intrinsic {
IfUninhabited => layout.abi.is_uninhabited(),
// We unwrap as the error type is `!`.
IfZeroInvalid => !layout.might_permit_raw_init(&bx, /*zero:*/ true).unwrap(),
// We unwrap as the error type is `!`.
IfAnyInvalid => !layout.might_permit_raw_init(&bx, /*zero:*/ false).unwrap(),
};
if do_panic {
let msg_str = if layout.abi.is_uninhabited() {
// Use this error even for the other intrinsics as it is more precise.
format!("attempted to instantiate uninhabited type `{}`", ty)
} else if intrinsic == IfZeroInvalid {
format!("attempted to zero-initialize type `{}`, which is invalid", ty)
} else {
format!("attempted to leave type `{}` uninitialized, which is invalid", ty)
};
let msg = bx.const_str(Symbol::intern(&msg_str));
let location = self.get_caller_location(&mut bx, span).immediate();
// Obtain the panic entry point.
// FIXME: dedup this with `codegen_assert_terminator` above.
let def_id =
common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem);
let instance = ty::Instance::mono(bx.tcx(), def_id);
let fn_abi = FnAbi::of_instance(&bx, instance, &[]);
let llfn = bx.get_fn_addr(instance);
if let Some((_, target)) = destination.as_ref() {
helper.maybe_sideeffect(self.mir, &mut bx, &[*target]);
}
// Codegen the actual panic invoke/call.
helper.do_call(
self,
&mut bx,
fn_abi,
llfn,
&[msg.0, msg.1, location],
destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)),
cleanup,
);
} else {
// a NOP
let target = destination.as_ref().unwrap().1;
helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
helper.funclet_br(self, &mut bx, target)
}
if self.codegen_panic_intrinsic(
&helper,
&mut bx,
intrinsic,
instance,
span,
destination,
cleanup,
) {
return;
}