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rustc_abi: also support debugging function pointers
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@RalfJung
RalfJung committed Sep 6, 2023
1 parent ab45885 commit 9570cac
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Showing 4 changed files with 190 additions and 44 deletions.
2 changes: 1 addition & 1 deletion compiler/rustc_passes/messages.ftl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ passes_abi =
abi: {$abi}
passes_abi_of =
fn_abi_of_instance({$fn_name}) = {$fn_abi}
fn_abi_of({$fn_name}) = {$fn_abi}
passes_align =
align: {$align}
Expand Down
124 changes: 87 additions & 37 deletions compiler/rustc_passes/src/abi_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,9 +2,10 @@ use rustc_ast::Attribute;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId;
use rustc_middle::ty::layout::{FnAbiError, LayoutError};
use rustc_middle::ty::{self, GenericArgs, Instance, TyCtxt};
use rustc_middle::ty::{self, GenericArgs, Instance, Ty, TyCtxt};
use rustc_span::source_map::Spanned;
use rustc_span::symbol::sym;
use rustc_target::abi::call::FnAbi;

use crate::errors::{AbiOf, UnrecognizedField};

Expand All @@ -17,15 +18,20 @@ pub fn test_abi(tcx: TyCtxt<'_>) {
match tcx.def_kind(id.owner_id) {
DefKind::Fn => {
for attr in tcx.get_attrs(id.owner_id, sym::rustc_abi) {
dump_abi_of(tcx, id.owner_id.def_id.into(), attr);
dump_abi_of_fn_item(tcx, id.owner_id.def_id.into(), attr);
}
}
DefKind::TyAlias { .. } => {
for attr in tcx.get_attrs(id.owner_id, sym::rustc_abi) {
dump_abi_of_fn_type(tcx, id.owner_id.def_id.into(), attr);
}
}
DefKind::Impl { .. } => {
// To find associated functions we need to go into the child items here.
for &id in tcx.associated_item_def_ids(id.owner_id) {
if matches!(tcx.def_kind(id), DefKind::AssocFn) {
for attr in tcx.get_attrs(id, sym::rustc_abi) {
dump_abi_of(tcx, id, attr);
dump_abi_of_fn_item(tcx, id, attr);
}
}
}
Expand All @@ -35,7 +41,32 @@ pub fn test_abi(tcx: TyCtxt<'_>) {
}
}

fn dump_abi_of(tcx: TyCtxt<'_>, item_def_id: DefId, attr: &Attribute) {
fn unwrap_fn_abi<'tcx>(
abi: Result<&'tcx FnAbi<'tcx, Ty<'tcx>>, &'tcx FnAbiError<'tcx>>,
tcx: TyCtxt<'tcx>,
item_def_id: DefId,
) -> &'tcx FnAbi<'tcx, Ty<'tcx>> {
match abi {
Ok(abi) => abi,
Err(FnAbiError::Layout(layout_error)) => {
tcx.sess.emit_fatal(Spanned {
node: layout_error.into_diagnostic(),
span: tcx.def_span(item_def_id),
});
}
Err(FnAbiError::AdjustForForeignAbi(e)) => {
// Sadly there seems to be no `into_diagnostic` for this case... and I am not sure if
// this can even be reached. Anyway this is a perma-unstable debug attribute, an ICE
// isn't the worst thing. Also this matches what codegen does.
span_bug!(
tcx.def_span(item_def_id),
"error computing fn_abi_of_instance, cannot adjust for foreign ABI: {e:?}",
)
}
}
}

fn dump_abi_of_fn_item(tcx: TyCtxt<'_>, item_def_id: DefId, 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, args) {
Expand All @@ -51,43 +82,62 @@ fn dump_abi_of(tcx: TyCtxt<'_>, item_def_id: DefId, attr: &Attribute) {
}
Err(_guaranteed) => return,
};
match tcx.fn_abi_of_instance(param_env.and((instance, /* extra_args */ ty::List::empty()))) {
Ok(abi) => {
// Check out the `#[rustc_abi(..)]` attribute to tell what to dump.
// The `..` are the names of fields to dump.
let meta_items = attr.meta_item_list().unwrap_or_default();
for meta_item in meta_items {
match meta_item.name_or_empty() {
sym::debug => {
let fn_name = tcx.item_name(item_def_id);
tcx.sess.emit_err(AbiOf {
span: tcx.def_span(item_def_id),
fn_name,
fn_abi: format!("{:#?}", abi),
});
}
let abi = unwrap_fn_abi(
tcx.fn_abi_of_instance(param_env.and((instance, /* extra_args */ ty::List::empty()))),
tcx,
item_def_id,
);

name => {
tcx.sess.emit_err(UnrecognizedField { span: meta_item.span(), name });
}
}
// Check out the `#[rustc_abi(..)]` attribute to tell what to dump.
// The `..` are the names of fields to dump.
let meta_items = attr.meta_item_list().unwrap_or_default();
for meta_item in meta_items {
match meta_item.name_or_empty() {
sym::debug => {
let fn_name = tcx.item_name(item_def_id);
tcx.sess.emit_err(AbiOf {
span: tcx.def_span(item_def_id),
fn_name,
fn_abi: format!("{:#?}", abi),
});
}
}

Err(FnAbiError::Layout(layout_error)) => {
tcx.sess.emit_fatal(Spanned {
node: layout_error.into_diagnostic(),
span: tcx.def_span(item_def_id),
});
name => {
tcx.sess.emit_err(UnrecognizedField { span: meta_item.span(), name });
}
}
Err(FnAbiError::AdjustForForeignAbi(e)) => {
// Sadly there seems to be no `into_diagnostic` for this case... and I am not sure if
// this can even be reached. Anyway this is a perma-unstable debug attribute, an ICE
// isn't the worst thing. Also this matches what codegen does.
span_bug!(
tcx.def_span(item_def_id),
"error computing fn_abi_of_instance, cannot adjust for foreign ABI: {e:?}",
)
}
}

fn dump_abi_of_fn_type(tcx: TyCtxt<'_>, item_def_id: DefId, attr: &Attribute) {
let param_env = tcx.param_env(item_def_id);
let ty = tcx.type_of(item_def_id).instantiate_identity();
let meta_items = attr.meta_item_list().unwrap_or_default();
for meta_item in meta_items {
match meta_item.name_or_empty() {
sym::debug => {
let ty::FnPtr(sig) = ty.kind() else {
span_bug!(
meta_item.span(),
"`#[rustc_abi(debug)]` on a type alias requires function pointer type"
);
};
let abi = unwrap_fn_abi(
tcx.fn_abi_of_fn_ptr(param_env.and((*sig, /* extra_args */ ty::List::empty()))),
tcx,
item_def_id,
);

let fn_name = tcx.item_name(item_def_id);
tcx.sess.emit_err(AbiOf {
span: tcx.def_span(item_def_id),
fn_name,
fn_abi: format!("{:#?}", abi),
});
}
name => {
tcx.sess.emit_err(UnrecognizedField { span: meta_item.span(), name });
}
}
}
}
2 changes: 2 additions & 0 deletions tests/ui/abi/debug.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@
#[rustc_abi(debug)]
fn test(_x: u8) -> bool { true } //~ ERROR: fn_abi

#[rustc_abi(debug)]
type TestFnPtr = fn(bool) -> u8; //~ ERROR: fn_abi

#[rustc_abi(debug)]
fn test_generic<T>(_x: *const T) { } //~ ERROR: fn_abi
Expand Down
106 changes: 100 additions & 6 deletions tests/ui/abi/debug.stderr
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
error: fn_abi_of_instance(test) = FnAbi {
error: fn_abi_of(test) = FnAbi {
args: [
ArgAbi {
layout: TyAndLayout {
Expand Down Expand Up @@ -92,7 +92,101 @@ error: fn_abi_of_instance(test) = FnAbi {
LL | fn test(_x: u8) -> bool { true }
| ^^^^^^^^^^^^^^^^^^^^^^^

error: fn_abi_of_instance(test_generic) = FnAbi {
error: fn_abi_of(TestFnPtr) = FnAbi {
args: [
ArgAbi {
layout: TyAndLayout {
ty: bool,
layout: Layout {
size: Size(1 bytes),
align: AbiAndPrefAlign {
abi: $SOME_ALIGN,
pref: $SOME_ALIGN,
},
abi: Scalar(
Initialized {
value: Int(
I8,
false,
),
valid_range: 0..=1,
},
),
fields: Primitive,
largest_niche: Some(
Niche {
offset: Size(0 bytes),
value: Int(
I8,
false,
),
valid_range: 0..=1,
},
),
variants: Single {
index: 0,
},
max_repr_align: None,
unadjusted_abi_align: $SOME_ALIGN,
},
},
mode: Direct(
ArgAttributes {
regular: NoUndef,
arg_ext: Zext,
pointee_size: Size(0 bytes),
pointee_align: None,
},
),
},
],
ret: ArgAbi {
layout: TyAndLayout {
ty: u8,
layout: Layout {
size: Size(1 bytes),
align: AbiAndPrefAlign {
abi: $SOME_ALIGN,
pref: $SOME_ALIGN,
},
abi: Scalar(
Initialized {
value: Int(
I8,
false,
),
valid_range: 0..=255,
},
),
fields: Primitive,
largest_niche: None,
variants: Single {
index: 0,
},
max_repr_align: None,
unadjusted_abi_align: $SOME_ALIGN,
},
},
mode: Direct(
ArgAttributes {
regular: NoUndef,
arg_ext: None,
pointee_size: Size(0 bytes),
pointee_align: None,
},
),
},
c_variadic: false,
fixed_count: 1,
conv: Rust,
can_unwind: $SOME_BOOL,
}
--> $DIR/debug.rs:16:1
|
LL | type TestFnPtr = fn(bool) -> u8;
| ^^^^^^^^^^^^^^

error: fn_abi_of(test_generic) = FnAbi {
args: [
ArgAbi {
layout: TyAndLayout {
Expand Down Expand Up @@ -163,12 +257,12 @@ error: fn_abi_of_instance(test_generic) = FnAbi {
conv: Rust,
can_unwind: $SOME_BOOL,
}
--> $DIR/debug.rs:17:1
--> $DIR/debug.rs:19:1
|
LL | fn test_generic<T>(_x: *const T) { }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: fn_abi_of_instance(assoc_test) = FnAbi {
error: fn_abi_of(assoc_test) = FnAbi {
args: [
ArgAbi {
layout: TyAndLayout {
Expand Down Expand Up @@ -251,10 +345,10 @@ error: fn_abi_of_instance(assoc_test) = FnAbi {
conv: Rust,
can_unwind: $SOME_BOOL,
}
--> $DIR/debug.rs:22:5
--> $DIR/debug.rs:24:5
|
LL | fn assoc_test(&self) { }
| ^^^^^^^^^^^^^^^^^^^^

error: aborting due to 3 previous errors
error: aborting due to 4 previous errors

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