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Auto merge of #125507 - compiler-errors:type-length-limit, r=lcnr

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Re-implement a type-size based limit

r? lcnr

This PR reintroduces the type length limit added in #37789, which was accidentally made practically useless by the caching changes to `Ty::walk` in #72412, which caused the `walk` function to no longer walk over identical elements.

Hitting this length limit is not fatal unless we are in codegen -- so it shouldn't affect passes like the mir inliner which creates potentially very large types (which we observed, for example, when the new trait solver compiles `itertools` in `--release` mode).

This also increases the type length limit from `1048576 == 2 ** 20` to `2 ** 24`, which covers all of the code that can be reached with craterbot-check. Individual crates can increase the length limit further if desired.

Perf regression is mild and I think we should accept it -- reinstating this limit is important for the new trait solver and to make sure we don't accidentally hit more type-size related regressions in the future.

Fixes #125460
This commit is contained in:
bors 2024-07-03 11:56:36 +00:00
commit c872a1418a
54 changed files with 360 additions and 268 deletions
Download patch file Download diff file Expand all files Collapse all files

2
compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
View file

@ -3733,7 +3733,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
if tcx.is_diagnostic_item(sym::deref_method, method_did) {
let deref_target =
tcx.get_diagnostic_item(sym::deref_target).and_then(|deref_target| {
Instance::resolve(tcx, self.param_env, deref_target, method_args)
Instance::try_resolve(tcx, self.param_env, deref_target, method_args)
.transpose()
});
if let Some(Ok(instance)) = deref_target {

2
compiler/rustc_borrowck/src/diagnostics/region_errors.rs
View file

@ -949,7 +949,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
return;
}
if let Ok(Some(instance)) = ty::Instance::resolve(
if let Ok(Some(instance)) = ty::Instance::try_resolve(
tcx,
self.param_env,
*fn_did,

11
compiler/rustc_codegen_cranelift/src/abi/mod.rs
View file

@ -371,9 +371,14 @@ pub(crate) fn codegen_terminator_call<'tcx>(
// Handle special calls like intrinsics and empty drop glue.
let instance = if let ty::FnDef(def_id, fn_args) = *func.layout().ty.kind() {
let instance =
ty::Instance::expect_resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, fn_args)
.polymorphize(fx.tcx);
let instance = ty::Instance::expect_resolve(
fx.tcx,
ty::ParamEnv::reveal_all(),
def_id,
fn_args,
source_info.span,
)
.polymorphize(fx.tcx);
if is_call_from_compiler_builtins_to_upstream_monomorphization(fx.tcx, instance) {
if target.is_some() {

3
compiler/rustc_codegen_cranelift/src/main_shim.rs
View file

@ -4,6 +4,7 @@ use rustc_middle::ty::AssocKind;
use rustc_middle::ty::GenericArg;
use rustc_session::config::{sigpipe, EntryFnType};
use rustc_span::symbol::Ident;
use rustc_span::DUMMY_SP;
use crate::prelude::*;
@ -119,6 +120,7 @@ pub(crate) fn maybe_create_entry_wrapper(
ParamEnv::reveal_all(),
report.def_id,
tcx.mk_args(&[GenericArg::from(main_ret_ty)]),
DUMMY_SP,
)
.polymorphize(tcx);
@ -144,6 +146,7 @@ pub(crate) fn maybe_create_entry_wrapper(
ParamEnv::reveal_all(),
start_def_id,
tcx.mk_args(&[main_ret_ty.into()]),
DUMMY_SP,
)
.polymorphize(tcx);
let start_func_id = import_function(tcx, m, start_instance);

3
compiler/rustc_codegen_gcc/src/context.rs
View file

@ -17,7 +17,7 @@ use rustc_middle::ty::layout::{
};
use rustc_middle::ty::{self, Instance, ParamEnv, PolyExistentialTraitRef, Ty, TyCtxt};
use rustc_session::Session;
use rustc_span::{source_map::respan, Span};
use rustc_span::{source_map::respan, Span, DUMMY_SP};
use rustc_target::abi::{
call::FnAbi, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx,
};
@ -479,6 +479,7 @@ impl<'gcc, 'tcx> MiscMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
ty::ParamEnv::reveal_all(),
def_id,
ty::List::empty(),
DUMMY_SP,
);
let symbol_name = tcx.symbol_name(instance).name;

3
compiler/rustc_codegen_llvm/src/context.rs
View file

@ -28,7 +28,7 @@ use rustc_session::config::{BranchProtection, CFGuard, CFProtection};
use rustc_session::config::{CrateType, DebugInfo, PAuthKey, PacRet};
use rustc_session::Session;
use rustc_span::source_map::Spanned;
use rustc_span::Span;
use rustc_span::{Span, DUMMY_SP};
use rustc_target::abi::{call::FnAbi, HasDataLayout, TargetDataLayout, VariantIdx};
use rustc_target::spec::{HasTargetSpec, RelocModel, Target, TlsModel};
use smallvec::SmallVec;
@ -580,6 +580,7 @@ impl<'ll, 'tcx> MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
ty::ParamEnv::reveal_all(),
def_id,
ty::List::empty(),
DUMMY_SP,
)),
_ => {
let name = name.unwrap_or("rust_eh_personality");

3
compiler/rustc_codegen_ssa/src/base.rs
View file

@ -37,7 +37,7 @@ use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
use rustc_session::config::{self, CrateType, EntryFnType, OptLevel, OutputType};
use rustc_session::Session;
use rustc_span::symbol::sym;
use rustc_span::Symbol;
use rustc_span::{Symbol, DUMMY_SP};
use rustc_target::abi::FIRST_VARIANT;
use std::cmp;
@ -467,6 +467,7 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
ty::ParamEnv::reveal_all(),
start_def_id,
cx.tcx().mk_args(&[main_ret_ty.into()]),
DUMMY_SP,
);
let start_fn = cx.get_fn_addr(start_instance);

1
compiler/rustc_codegen_ssa/src/mir/block.rs
View file

@ -842,6 +842,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
ty::ParamEnv::reveal_all(),
def_id,
args,
fn_span,
)
.polymorphize(bx.tcx()),
),

2
compiler/rustc_const_eval/src/check_consts/check.rs
View file

@ -768,7 +768,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
is_trait = true;
if let Ok(Some(instance)) =
Instance::resolve(tcx, param_env, callee, fn_args)
Instance::try_resolve(tcx, param_env, callee, fn_args)
&& let InstanceKind::Item(def) = instance.def
{
// Resolve a trait method call to its concrete implementation, which may be in a

1
compiler/rustc_const_eval/src/const_eval/machine.rs
View file

@ -253,6 +253,7 @@ impl<'tcx> CompileTimeInterpCx<'tcx> {
ty::ParamEnv::reveal_all(),
const_def_id,
instance.args,
self.cur_span(),
);
return Ok(Some(new_instance));

2
compiler/rustc_const_eval/src/interpret/eval_context.rs
View file

@ -618,7 +618,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
trace!("resolve: {:?}, {:#?}", def, args);
trace!("param_env: {:#?}", self.param_env);
trace!("args: {:#?}", args);
match ty::Instance::resolve(*self.tcx, self.param_env, def, args) {
match ty::Instance::try_resolve(*self.tcx, self.param_env, def, args) {
Ok(Some(instance)) => Ok(instance),
Ok(None) => throw_inval!(TooGeneric),

6
compiler/rustc_const_eval/src/interpret/terminator.rs
View file

@ -883,13 +883,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
ty::ExistentialTraitRef::erase_self_ty(tcx, virtual_trait_ref);
let concrete_trait_ref = existential_trait_ref.with_self_ty(tcx, dyn_ty);
let concrete_method = Instance::resolve_for_vtable(
let concrete_method = Instance::expect_resolve_for_vtable(
tcx,
self.param_env,
def_id,
instance.args.rebase_onto(tcx, trait_def_id, concrete_trait_ref.args),
)
.unwrap();
self.cur_span(),
);
assert_eq!(fn_inst, concrete_method);
}

2
compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
View file

@ -534,7 +534,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
let tcx = self.tcx();
// Find the method being called.
let Ok(Some(instance)) = ty::Instance::resolve(
let Ok(Some(instance)) = ty::Instance::try_resolve(
tcx,
ctxt.param_env,
ctxt.assoc_item.def_id,

4
compiler/rustc_lint/src/internal.rs
View file

@ -88,7 +88,7 @@ declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY]);
impl LateLintPass<'_> for QueryStability {
fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
let Some((span, def_id, args)) = typeck_results_of_method_fn(cx, expr) else { return };
if let Ok(Some(instance)) = ty::Instance::resolve(cx.tcx, cx.param_env, def_id, args) {
if let Ok(Some(instance)) = ty::Instance::try_resolve(cx.tcx, cx.param_env, def_id, args) {
let def_id = instance.def_id();
if cx.tcx.has_attr(def_id, sym::rustc_lint_query_instability) {
cx.emit_span_lint(
@ -393,7 +393,7 @@ impl LateLintPass<'_> for Diagnostics {
};
// Is the callee marked with `#[rustc_lint_diagnostics]`?
let has_attr = ty::Instance::resolve(cx.tcx, cx.param_env, def_id, fn_gen_args)
let has_attr = ty::Instance::try_resolve(cx.tcx, cx.param_env, def_id, fn_gen_args)
.ok()
.flatten()
.is_some_and(|inst| cx.tcx.has_attr(inst.def_id(), sym::rustc_lint_diagnostics));

4
compiler/rustc_lint/src/noop_method_call.rs
View file

@ -96,7 +96,9 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
.tcx
.normalize_erasing_regions(cx.param_env, cx.typeck_results().node_args(expr.hir_id));
// Resolve the trait method instance.
let Ok(Some(i)) = ty::Instance::resolve(cx.tcx, cx.param_env, did, args) else { return };
let Ok(Some(i)) = ty::Instance::try_resolve(cx.tcx, cx.param_env, did, args) else {
return;
};
// (Re)check that it implements the noop diagnostic.
let Some(name) = cx.tcx.get_diagnostic_name(i.def_id()) else { return };
if !matches!(

6
compiler/rustc_middle/messages.ftl
View file

@ -41,6 +41,9 @@ middle_cannot_be_normalized =
middle_conflict_types =
this expression supplies two conflicting concrete types for the same opaque type
middle_consider_type_length_limit =
consider adding a `#![type_length_limit="{$type_length}"]` attribute to your crate
middle_const_eval_non_int =
constant evaluation of enum discriminant resulted in non-integer
@ -94,8 +97,11 @@ middle_strict_coherence_needs_negative_coherence =
to use `strict_coherence` on this trait, the `with_negative_coherence` feature must be enabled
.label = due to this attribute
middle_type_length_limit = reached the type-length limit while instantiating `{$shrunk}`
middle_unknown_layout =
the type `{$ty}` has an unknown layout
middle_values_too_big =
values of the type `{$ty}` are too big for the current architecture
middle_written_to_path = the full type name has been written to '{$path}'

14
compiler/rustc_middle/src/error.rs
View file

@ -1,4 +1,5 @@
use std::fmt;
use std::path::PathBuf;
use rustc_errors::{codes::*, DiagArgName, DiagArgValue, DiagMessage};
use rustc_macros::{Diagnostic, Subdiagnostic};
@ -149,3 +150,16 @@ pub struct ErroneousConstant {
/// Used by `rustc_const_eval`
pub use crate::fluent_generated::middle_adjust_for_foreign_abi_error;
#[derive(Diagnostic)]
#[diag(middle_type_length_limit)]
#[help(middle_consider_type_length_limit)]
pub struct TypeLengthLimit {
#[primary_span]
pub span: Span,
pub shrunk: String,
#[note(middle_written_to_path)]
pub was_written: Option<()>,
pub path: PathBuf,
pub type_length: usize,
}

2
compiler/rustc_middle/src/middle/limits.rs
View file

@ -30,7 +30,7 @@ pub fn provide(providers: &mut Providers) {
tcx.hir().krate_attrs(),
tcx.sess,
sym::type_length_limit,
1048576,
2usize.pow(24),
),
}
}

4
compiler/rustc_middle/src/mir/interpret/queries.rs
View file

@ -73,7 +73,7 @@ impl<'tcx> TyCtxt<'tcx> {
bug!("did not expect inference variables here");
}
match ty::Instance::resolve(
match ty::Instance::try_resolve(
self, param_env,
// FIXME: maybe have a separate version for resolving mir::UnevaluatedConst?
ct.def, ct.args,
@ -106,7 +106,7 @@ impl<'tcx> TyCtxt<'tcx> {
bug!("did not expect inference variables here");
}
match ty::Instance::resolve(self, param_env, ct.def, ct.args) {
match ty::Instance::try_resolve(self, param_env, ct.def, ct.args) {
Ok(Some(instance)) => {
let cid = GlobalId { instance, promoted: None };
self.const_eval_global_id_for_typeck(param_env, cid, span).inspect(|_| {

4
compiler/rustc_middle/src/query/mod.rs
View file

@ -2197,8 +2197,8 @@ rustc_queries! {
/// * `Err(ErrorGuaranteed)` when the `Instance` resolution process
/// couldn't complete due to errors elsewhere - this is distinct
/// from `Ok(None)` to avoid misleading diagnostics when an error
/// has already been/will be emitted, for the original cause
query resolve_instance(
/// has already been/will be emitted, for the original cause.
query resolve_instance_raw(
key: ty::ParamEnvAnd<'tcx, (DefId, GenericArgsRef<'tcx>)>
) -> Result<Option<ty::Instance<'tcx>>, ErrorGuaranteed> {
desc { "resolving instance `{}`", ty::Instance::new(key.value.0, key.value.1) }

239
compiler/rustc_middle/src/ty/instance.rs
View file

@ -1,23 +1,25 @@
use crate::error;
use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use crate::ty::print::{FmtPrinter, Printer};
use crate::ty::{self, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable};
use crate::ty::{EarlyBinder, GenericArgs, GenericArgsRef, TypeVisitableExt};
use crate::ty::print::{shrunk_instance_name, FmtPrinter, Printer};
use crate::ty::{
self, EarlyBinder, GenericArgs, GenericArgsRef, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable,
TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor,
};
use rustc_errors::ErrorGuaranteed;
use rustc_hir as hir;
use rustc_hir::def::Namespace;
use rustc_hir::def_id::{CrateNum, DefId};
use rustc_hir::lang_items::LangItem;
use rustc_index::bit_set::FiniteBitSet;
use rustc_macros::{
Decodable, Encodable, HashStable, Lift, TyDecodable, TyEncodable, TypeVisitable,
};
use rustc_macros::{Decodable, Encodable, HashStable, Lift, TyDecodable, TyEncodable};
use rustc_middle::ty::normalize_erasing_regions::NormalizationError;
use rustc_span::def_id::LOCAL_CRATE;
use rustc_span::Symbol;
use rustc_span::{Span, Symbol, DUMMY_SP};
use tracing::{debug, instrument};
use std::assert_matches::assert_matches;
use std::fmt;
use std::path::PathBuf;
/// An `InstanceKind` along with the args that are needed to substitute the instance.
///
@ -385,7 +387,28 @@ impl<'tcx> InstanceKind<'tcx> {
}
}
fn fmt_instance(
fn type_length<'tcx>(item: impl TypeVisitable<TyCtxt<'tcx>>) -> usize {
struct Visitor {
type_length: usize,
}
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for Visitor {
fn visit_ty(&mut self, t: Ty<'tcx>) {
self.type_length += 1;
t.super_visit_with(self);
}
fn visit_const(&mut self, ct: ty::Const<'tcx>) {
self.type_length += 1;
ct.super_visit_with(self);
}
}
let mut visitor = Visitor { type_length: 0 };
item.visit_with(&mut visitor);
visitor.type_length
}
pub fn fmt_instance(
f: &mut fmt::Formatter<'_>,
instance: Instance<'_>,
type_length: Option<rustc_session::Limit>,
@ -485,19 +508,30 @@ impl<'tcx> Instance<'tcx> {
///
/// Presuming that coherence and type-check have succeeded, if this method is invoked
/// in a monomorphic context (i.e., like during codegen), then it is guaranteed to return
/// `Ok(Some(instance))`.
/// `Ok(Some(instance))`, **except** for when the instance's inputs hit the type size limit,
/// in which case it may bail out and return `Ok(None)`.
///
/// Returns `Err(ErrorGuaranteed)` when the `Instance` resolution process
/// couldn't complete due to errors elsewhere - this is distinct
/// from `Ok(None)` to avoid misleading diagnostics when an error
/// has already been/will be emitted, for the original cause
#[instrument(level = "debug", skip(tcx), ret)]
pub fn resolve(
pub fn try_resolve(
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
def_id: DefId,
args: GenericArgsRef<'tcx>,
) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> {
// Rust code can easily create exponentially-long types using only a
// polynomial recursion depth. Even with the default recursion
// depth, you can easily get cases that take >2^60 steps to run,
// which means that rustc basically hangs.
//
// Bail out in these cases to avoid that bad user experience.
if !tcx.type_length_limit().value_within_limit(type_length(args)) {
return Ok(None);
}
// All regions in the result of this query are erased, so it's
// fine to erase all of the input regions.
@ -505,7 +539,7 @@ impl<'tcx> Instance<'tcx> {
// below is more likely to ignore the bounds in scope (e.g. if the only
// generic parameters mentioned by `args` were lifetime ones).
let args = tcx.erase_regions(args);
tcx.resolve_instance(tcx.erase_regions(param_env.and((def_id, args))))
tcx.resolve_instance_raw(tcx.erase_regions(param_env.and((def_id, args))))
}
pub fn expect_resolve(
@ -513,10 +547,48 @@ impl<'tcx> Instance<'tcx> {
param_env: ty::ParamEnv<'tcx>,
def_id: DefId,
args: GenericArgsRef<'tcx>,
span: Span,
) -> Instance<'tcx> {
match ty::Instance::resolve(tcx, param_env, def_id, args) {
// We compute the span lazily, to avoid unnecessary query calls.
// If `span` is a DUMMY_SP, and the def id is local, then use the
// def span of the def id.
let span_or_local_def_span =
|| if span.is_dummy() && def_id.is_local() { tcx.def_span(def_id) } else { span };
match ty::Instance::try_resolve(tcx, param_env, def_id, args) {
Ok(Some(instance)) => instance,
instance => bug!(
Ok(None) => {
let type_length = type_length(args);
if !tcx.type_length_limit().value_within_limit(type_length) {
let (shrunk, written_to_path) =
shrunk_instance_name(tcx, Instance::new(def_id, args));
let mut path = PathBuf::new();
let was_written = if let Some(path2) = written_to_path {
path = path2;
Some(())
} else {
None
};
tcx.dcx().emit_fatal(error::TypeLengthLimit {
// We don't use `def_span(def_id)` so that diagnostics point
// to the crate root during mono instead of to foreign items.
// This is arguably better.
span: span_or_local_def_span(),
shrunk,
was_written,
path,
type_length,
});
} else {
span_bug!(
span_or_local_def_span(),
"failed to resolve instance for {}",
tcx.def_path_str_with_args(def_id, args)
)
}
}
instance => span_bug!(
span_or_local_def_span(),
"failed to resolve instance for {}: {instance:#?}",
tcx.def_path_str_with_args(def_id, args)
),
@ -533,7 +605,7 @@ impl<'tcx> Instance<'tcx> {
// Use either `resolve_closure` or `resolve_for_vtable`
assert!(!tcx.is_closure_like(def_id), "Called `resolve_for_fn_ptr` on closure: {def_id:?}");
let reason = tcx.sess.is_sanitizer_kcfi_enabled().then_some(ReifyReason::FnPtr);
Instance::resolve(tcx, param_env, def_id, args).ok().flatten().map(|mut resolved| {
Instance::try_resolve(tcx, param_env, def_id, args).ok().flatten().map(|mut resolved| {
match resolved.def {
InstanceKind::Item(def) if resolved.def.requires_caller_location(tcx) => {
debug!(" => fn pointer created for function with #[track_caller]");
@ -571,77 +643,82 @@ impl<'tcx> Instance<'tcx> {
})
}
pub fn resolve_for_vtable(
pub fn expect_resolve_for_vtable(
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
def_id: DefId,
args: GenericArgsRef<'tcx>,
) -> Option<Instance<'tcx>> {
span: Span,
) -> Instance<'tcx> {
debug!("resolve_for_vtable(def_id={:?}, args={:?})", def_id, args);
let fn_sig = tcx.fn_sig(def_id).instantiate_identity();
let is_vtable_shim = !fn_sig.inputs().skip_binder().is_empty()
&& fn_sig.input(0).skip_binder().is_param(0)
&& tcx.generics_of(def_id).has_self;
if is_vtable_shim {
debug!(" => associated item with unsizeable self: Self");
Some(Instance { def: InstanceKind::VTableShim(def_id), args })
} else {
let reason = tcx.sess.is_sanitizer_kcfi_enabled().then_some(ReifyReason::Vtable);
Instance::resolve(tcx, param_env, def_id, args).ok().flatten().map(|mut resolved| {
match resolved.def {
InstanceKind::Item(def) => {
// We need to generate a shim when we cannot guarantee that
// the caller of a trait object method will be aware of
// `#[track_caller]` - this ensures that the caller
// and callee ABI will always match.
//
// The shim is generated when all of these conditions are met:
//
// 1) The underlying method expects a caller location parameter
// in the ABI
if resolved.def.requires_caller_location(tcx)
// 2) The caller location parameter comes from having `#[track_caller]`
// on the implementation, and *not* on the trait method.
&& !tcx.should_inherit_track_caller(def)
// If the method implementation comes from the trait definition itself
// (e.g. `trait Foo { #[track_caller] my_fn() { /* impl */ } }`),
// then we don't need to generate a shim. This check is needed because
// `should_inherit_track_caller` returns `false` if our method
// implementation comes from the trait block, and not an impl block
&& !matches!(
tcx.opt_associated_item(def),
Some(ty::AssocItem {
container: ty::AssocItemContainer::TraitContainer,
..
})
)
{
if tcx.is_closure_like(def) {
debug!(" => vtable fn pointer created for closure with #[track_caller]: {:?} for method {:?} {:?}",
def, def_id, args);
// Create a shim for the `FnOnce/FnMut/Fn` method we are calling
// - unlike functions, invoking a closure always goes through a
// trait.
resolved = Instance { def: InstanceKind::ReifyShim(def_id, reason), args };
} else {
debug!(
" => vtable fn pointer created for function with #[track_caller]: {:?}", def
);
resolved.def = InstanceKind::ReifyShim(def, reason);
}
}
}
InstanceKind::Virtual(def_id, _) => {
debug!(" => vtable fn pointer created for virtual call");
resolved.def = InstanceKind::ReifyShim(def_id, reason)
}
_ => {}
}
resolved
})
return Instance { def: InstanceKind::VTableShim(def_id), args };
}
let mut resolved = Instance::expect_resolve(tcx, param_env, def_id, args, span);
let reason = tcx.sess.is_sanitizer_kcfi_enabled().then_some(ReifyReason::Vtable);
match resolved.def {
InstanceKind::Item(def) => {
// We need to generate a shim when we cannot guarantee that
// the caller of a trait object method will be aware of
// `#[track_caller]` - this ensures that the caller
// and callee ABI will always match.
//
// The shim is generated when all of these conditions are met:
//
// 1) The underlying method expects a caller location parameter
// in the ABI
if resolved.def.requires_caller_location(tcx)
// 2) The caller location parameter comes from having `#[track_caller]`
// on the implementation, and *not* on the trait method.
&& !tcx.should_inherit_track_caller(def)
// If the method implementation comes from the trait definition itself
// (e.g. `trait Foo { #[track_caller] my_fn() { /* impl */ } }`),
// then we don't need to generate a shim. This check is needed because
// `should_inherit_track_caller` returns `false` if our method
// implementation comes from the trait block, and not an impl block
&& !matches!(
tcx.opt_associated_item(def),
Some(ty::AssocItem {
container: ty::AssocItemContainer::TraitContainer,
..
})
)
{
if tcx.is_closure_like(def) {
debug!(
" => vtable fn pointer created for closure with #[track_caller]: {:?} for method {:?} {:?}",
def, def_id, args
);
// Create a shim for the `FnOnce/FnMut/Fn` method we are calling
// - unlike functions, invoking a closure always goes through a
// trait.
resolved = Instance { def: InstanceKind::ReifyShim(def_id, reason), args };
} else {
debug!(
" => vtable fn pointer created for function with #[track_caller]: {:?}",
def
);
resolved.def = InstanceKind::ReifyShim(def, reason);
}
}
}
InstanceKind::Virtual(def_id, _) => {
debug!(" => vtable fn pointer created for virtual call");
resolved.def = InstanceKind::ReifyShim(def_id, reason)
}
_ => {}
}
resolved
}
pub fn resolve_closure(
@ -661,13 +738,25 @@ impl<'tcx> Instance<'tcx> {
pub fn resolve_drop_in_place(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ty::Instance<'tcx> {
let def_id = tcx.require_lang_item(LangItem::DropInPlace, None);
let args = tcx.mk_args(&[ty.into()]);
Instance::expect_resolve(tcx, ty::ParamEnv::reveal_all(), def_id, args)
Instance::expect_resolve(
tcx,
ty::ParamEnv::reveal_all(),
def_id,
args,
ty.ty_adt_def().and_then(|adt| tcx.hir().span_if_local(adt.did())).unwrap_or(DUMMY_SP),
)
}
pub fn resolve_async_drop_in_place(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ty::Instance<'tcx> {
let def_id = tcx.require_lang_item(LangItem::AsyncDropInPlace, None);
let args = tcx.mk_args(&[ty.into()]);
Instance::expect_resolve(tcx, ty::ParamEnv::reveal_all(), def_id, args)
Instance::expect_resolve(
tcx,
ty::ParamEnv::reveal_all(),
def_id,
args,
ty.ty_adt_def().and_then(|adt| tcx.hir().span_if_local(adt.did())).unwrap_or(DUMMY_SP),
)
}
#[instrument(level = "debug", skip(tcx), ret)]

32
compiler/rustc_middle/src/ty/print/mod.rs
View file

@ -1,5 +1,7 @@
use std::path::PathBuf;
use crate::ty::GenericArg;
use crate::ty::{self, Ty, TyCtxt};
use crate::ty::{self, ShortInstance, Ty, TyCtxt};
use hir::def::Namespace;
use rustc_data_structures::fx::FxHashSet;
@ -356,3 +358,31 @@ where
with_no_trimmed_paths!(Self::print(t, fmt))
}
}
/// Format instance name that is already known to be too long for rustc.
/// Show only the first 2 types if it is longer than 32 characters to avoid blasting
/// the user's terminal with thousands of lines of type-name.
///
/// If the type name is longer than before+after, it will be written to a file.
pub fn shrunk_instance_name<'tcx>(
tcx: TyCtxt<'tcx>,
instance: ty::Instance<'tcx>,
) -> (String, Option<PathBuf>) {
let s = instance.to_string();
// Only use the shrunk version if it's really shorter.
// This also avoids the case where before and after slices overlap.
if s.chars().nth(33).is_some() {
let shrunk = format!("{}", ShortInstance(instance, 4));
if shrunk == s {
return (s, None);
}
let path = tcx.output_filenames(()).temp_path_ext("long-type.txt", None);
let written_to_path = std::fs::write(&path, s).ok().map(|_| path);
(shrunk, written_to_path)
} else {
(s, None)
}
}

2
compiler/rustc_middle/src/util/call_kind.rs
View file

@ -98,7 +98,7 @@ pub fn call_kind<'tcx>(
Some(CallKind::Operator { self_arg, trait_id, self_ty: method_args.type_at(0) })
} else if is_deref {
let deref_target = tcx.get_diagnostic_item(sym::deref_target).and_then(|deref_target| {
Instance::resolve(tcx, param_env, deref_target, method_args).transpose()
Instance::try_resolve(tcx, param_env, deref_target, method_args).transpose()
});
if let Some(Ok(instance)) = deref_target {
let deref_target_ty = instance.ty(tcx, param_env);

2
compiler/rustc_mir_build/src/lints.rs
View file

@ -141,7 +141,7 @@ impl<'tcx> TerminatorClassifier<'tcx> for CallRecursion<'tcx> {
return false;
};
let (callee, call_args) = if let Ok(Some(instance)) =
Instance::resolve(tcx, param_env, callee, normalized_args)
Instance::try_resolve(tcx, param_env, callee, normalized_args)
{
(instance.def_id(), instance.args)
} else {

3
compiler/rustc_mir_build/src/thir/pattern/mod.rs
View file

@ -558,7 +558,8 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
let args = self
.tcx
.normalize_erasing_regions(param_env_reveal_all, self.typeck_results.node_args(id));
let instance = match ty::Instance::resolve(self.tcx, param_env_reveal_all, def_id, args) {
let instance = match ty::Instance::try_resolve(self.tcx, param_env_reveal_all, def_id, args)
{
Ok(Some(i)) => i,
Ok(None) => {
// It should be assoc consts if there's no error but we cannot resolve it.

2
compiler/rustc_mir_transform/src/inline.rs
View file

@ -389,7 +389,7 @@ impl<'tcx> Inliner<'tcx> {
// To resolve an instance its args have to be fully normalized.
let args = self.tcx.try_normalize_erasing_regions(self.param_env, args).ok()?;
let callee =
Instance::resolve(self.tcx, self.param_env, def_id, args).ok().flatten()?;
Instance::try_resolve(self.tcx, self.param_env, def_id, args).ok().flatten()?;
if let InstanceKind::Virtual(..) | InstanceKind::Intrinsic(_) = callee.def {
return None;

2
compiler/rustc_mir_transform/src/inline/cycle.rs
View file

@ -53,7 +53,7 @@ pub(crate) fn mir_callgraph_reachable<'tcx>(
trace!(?caller, ?param_env, ?args, "cannot normalize, skipping");
continue;
};
let Ok(Some(callee)) = ty::Instance::resolve(tcx, param_env, callee, args) else {
let Ok(Some(callee)) = ty::Instance::try_resolve(tcx, param_env, callee, args) else {
trace!(?callee, "cannot resolve, skipping");
continue;
};

5
compiler/rustc_monomorphize/messages.ftl
View file

@ -1,6 +1,3 @@
monomorphize_consider_type_length_limit =
consider adding a `#![type_length_limit="{$type_length}"]` attribute to your crate
monomorphize_couldnt_dump_mono_stats =
unexpected error occurred while dumping monomorphization stats: {$error}
@ -25,8 +22,6 @@ monomorphize_start_not_found = using `fn main` requires the standard library
monomorphize_symbol_already_defined = symbol `{$symbol}` is already defined
monomorphize_type_length_limit = reached the type-length limit while instantiating `{$shrunk}`
monomorphize_unknown_cgu_collection_mode =
unknown codegen-item collection mode '{$mode}', falling back to 'lazy' mode

79
compiler/rustc_monomorphize/src/collector.rs
View file

@ -222,12 +222,12 @@ use rustc_middle::mir::{self, Location, MentionedItem};
use rustc_middle::query::TyCtxtAt;
use rustc_middle::ty::adjustment::{CustomCoerceUnsized, PointerCoercion};
use rustc_middle::ty::layout::ValidityRequirement;
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::print::{shrunk_instance_name, with_no_trimmed_paths};
use rustc_middle::ty::GenericArgs;
use rustc_middle::ty::{
self, AssocKind, GenericParamDefKind, Instance, InstanceKind, Ty, TyCtxt, TypeFoldable,
TypeVisitableExt, VtblEntry,
};
use rustc_middle::ty::{GenericArgKind, GenericArgs};
use rustc_middle::{bug, span_bug};
use rustc_session::config::EntryFnType;
use rustc_session::Limit;
@ -238,9 +238,7 @@ use rustc_target::abi::Size;
use std::path::PathBuf;
use tracing::{debug, instrument, trace};
use crate::errors::{
self, EncounteredErrorWhileInstantiating, NoOptimizedMir, RecursionLimit, TypeLengthLimit,
};
use crate::errors::{self, EncounteredErrorWhileInstantiating, NoOptimizedMir, RecursionLimit};
use move_check::MoveCheckState;
#[derive(PartialEq)]
@ -443,7 +441,6 @@ fn collect_items_rec<'tcx>(
recursion_depths,
recursion_limit,
));
check_type_length_limit(tcx, instance);
rustc_data_structures::stack::ensure_sufficient_stack(|| {
collect_items_of_instance(
@ -554,34 +551,6 @@ fn collect_items_rec<'tcx>(
}
}
/// Format instance name that is already known to be too long for rustc.
/// Show only the first 2 types if it is longer than 32 characters to avoid blasting
/// the user's terminal with thousands of lines of type-name.
///
/// If the type name is longer than before+after, it will be written to a file.
fn shrunk_instance_name<'tcx>(
tcx: TyCtxt<'tcx>,
instance: Instance<'tcx>,
) -> (String, Option<PathBuf>) {
let s = instance.to_string();
// Only use the shrunk version if it's really shorter.
// This also avoids the case where before and after slices overlap.
if s.chars().nth(33).is_some() {
let shrunk = format!("{}", ty::ShortInstance(instance, 4));
if shrunk == s {
return (s, None);
}
let path = tcx.output_filenames(()).temp_path_ext("long-type.txt", None);
let written_to_path = std::fs::write(&path, s).ok().map(|_| path);
(shrunk, written_to_path)
} else {
(s, None)
}
}
fn check_recursion_limit<'tcx>(
tcx: TyCtxt<'tcx>,
instance: Instance<'tcx>,
@ -630,38 +599,6 @@ fn check_recursion_limit<'tcx>(
(def_id, recursion_depth)
}
fn check_type_length_limit<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) {
let type_length = instance
.args
.iter()
.flat_map(|arg| arg.walk())
.filter(|arg| match arg.unpack() {
GenericArgKind::Type(_) | GenericArgKind::Const(_) => true,
GenericArgKind::Lifetime(_) => false,
})
.count();
debug!(" => type length={}", type_length);
// Rust code can easily create exponentially-long types using only a
// polynomial recursion depth. Even with the default recursion
// depth, you can easily get cases that take >2^60 steps to run,
// which means that rustc basically hangs.
//
// Bail out in these cases to avoid that bad user experience.
if !tcx.type_length_limit().value_within_limit(type_length) {
let (shrunk, written_to_path) = shrunk_instance_name(tcx, instance);
let span = tcx.def_span(instance.def_id());
let mut path = PathBuf::new();
let was_written = if let Some(path2) = written_to_path {
path = path2;
Some(())
} else {
None
};
tcx.dcx().emit_fatal(TypeLengthLimit { span, shrunk, was_written, path, type_length });
}
}
struct MirUsedCollector<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
body: &'a mir::Body<'tcx>,
@ -916,7 +853,7 @@ fn visit_fn_use<'tcx>(
) {
if let ty::FnDef(def_id, args) = *ty.kind() {
let instance = if is_direct_call {
ty::Instance::expect_resolve(tcx, ty::ParamEnv::reveal_all(), def_id, args)
ty::Instance::expect_resolve(tcx, ty::ParamEnv::reveal_all(), def_id, args, source)
} else {
match ty::Instance::resolve_for_fn_ptr(tcx, ty::ParamEnv::reveal_all(), def_id, args) {
Some(instance) => instance,
@ -1319,7 +1256,7 @@ fn visit_mentioned_item<'tcx>(
MentionedItem::Fn(ty) => {
if let ty::FnDef(def_id, args) = *ty.kind() {
let instance =
Instance::expect_resolve(tcx, ty::ParamEnv::reveal_all(), def_id, args);
Instance::expect_resolve(tcx, ty::ParamEnv::reveal_all(), def_id, args, span);
// `visit_instance_use` was written for "used" item collection but works just as well
// for "mentioned" item collection.
// We can set `is_direct_call`; that just means we'll skip a bunch of shims that anyway
@ -1544,6 +1481,7 @@ impl<'v> RootCollector<'_, 'v> {
ty::ParamEnv::reveal_all(),
start_def_id,
self.tcx.mk_args(&[main_ret_ty.into()]),
DUMMY_SP,
);
self.output.push(create_fn_mono_item(self.tcx, start_instance, DUMMY_SP));
@ -1612,9 +1550,10 @@ fn create_mono_items_for_default_impls<'tcx>(
}
// As mentioned above, the method is legal to eagerly instantiate if it
// only has lifetime generic parameters. This is validated by
// only has lifetime generic parameters. This is validated by calling
// `own_requires_monomorphization` on both the impl and method.
let args = trait_ref.args.extend_to(tcx, method.def_id, only_region_params);
let instance = ty::Instance::expect_resolve(tcx, param_env, method.def_id, args);
let instance = ty::Instance::expect_resolve(tcx, param_env, method.def_id, args, DUMMY_SP);
let mono_item = create_fn_mono_item(tcx, instance, DUMMY_SP);
if mono_item.node.is_instantiable(tcx) && should_codegen_locally(tcx, instance) {

13
compiler/rustc_monomorphize/src/errors.rs
View file

@ -19,19 +19,6 @@ pub struct RecursionLimit {
pub path: PathBuf,
}
#[derive(Diagnostic)]
#[diag(monomorphize_type_length_limit)]
#[help(monomorphize_consider_type_length_limit)]
pub struct TypeLengthLimit {
#[primary_span]
pub span: Span,
pub shrunk: String,
#[note(monomorphize_written_to_path)]
pub was_written: Option<()>,
pub path: PathBuf,
pub type_length: usize,
}
#[derive(Diagnostic)]
#[diag(monomorphize_no_optimized_mir)]
pub struct NoOptimizedMir {

2
compiler/rustc_passes/src/abi_test.rs
View file

@ -61,7 +61,7 @@ fn unwrap_fn_abi<'tcx>(
fn dump_abi_of_fn_item(tcx: TyCtxt<'_>, item_def_id: LocalDefId, attr: &Attribute) {
let param_env = tcx.param_env(item_def_id);
let args = GenericArgs::identity_for_item(tcx, item_def_id);
let instance = match Instance::resolve(tcx, param_env, item_def_id.into(), args) {
let instance = match Instance::try_resolve(tcx, param_env, item_def_id.into(), args) {
Ok(Some(instance)) => instance,
Ok(None) => {
// Not sure what to do here, but `LayoutError::Unknown` seems reasonable?

2
compiler/rustc_smir/src/rustc_smir/context.rs
View file

@ -629,7 +629,7 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
let tcx = tables.tcx;
let def_id = def.0.internal(&mut *tables, tcx);
let args_ref = args.internal(&mut *tables, tcx);
match Instance::resolve(tables.tcx, ParamEnv::reveal_all(), def_id, args_ref) {
match Instance::try_resolve(tables.tcx, ParamEnv::reveal_all(), def_id, args_ref) {
Ok(Some(instance)) => Some(instance.stable(&mut *tables)),
Ok(None) | Err(_) => None,
}

9
compiler/rustc_trait_selection/src/traits/vtable.rs
View file

@ -6,7 +6,7 @@ use rustc_middle::bug;
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, GenericParamDefKind, Ty, TyCtxt, Upcast, VtblEntry};
use rustc_middle::ty::{GenericArgs, TypeVisitableExt};
use rustc_span::{sym, Span};
use rustc_span::{sym, Span, DUMMY_SP};
use smallvec::{smallvec, SmallVec};
use std::fmt::Debug;
@ -285,13 +285,14 @@ fn vtable_entries<'tcx>(
return VtblEntry::Vacant;
}
let instance = ty::Instance::resolve_for_vtable(
let instance = ty::Instance::expect_resolve_for_vtable(
tcx,
ty::ParamEnv::reveal_all(),
def_id,
args,
)
.expect("resolution failed during building vtable representation");
DUMMY_SP,
);
VtblEntry::Method(instance)
});

4
compiler/rustc_ty_utils/src/instance.rs
View file

@ -16,7 +16,7 @@ use traits::{translate_args, Reveal};
use crate::errors::UnexpectedFnPtrAssociatedItem;
fn resolve_instance<'tcx>(
fn resolve_instance_raw<'tcx>(
tcx: TyCtxt<'tcx>,
key: ty::ParamEnvAnd<'tcx, (DefId, GenericArgsRef<'tcx>)>,
) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> {
@ -364,5 +364,5 @@ fn resolve_associated_item<'tcx>(
}
pub(crate) fn provide(providers: &mut Providers) {
*providers = Providers { resolve_instance, ..*providers };
*providers = Providers { resolve_instance_raw, ..*providers };
}