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Store names of captured variables in optimized_mir

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- Closures in external crates may get compiled in because of
  monomorphization. We should store names of captured variables
  in `optimized_mir`, so that they are written into the metadata
  file and we can use them to generate debuginfo.

- If there are breakpoints inside closures, the names of captured
  variables stored in `optimized_mir` can be used to print them.
  Now the name is more precise when disjoint fields are captured.
This commit is contained in:
lrh2000 2021-05-15 19:01:13 +08:00
parent 29856acffe
commit cda90f5541
7 changed files with 132 additions and 66 deletions
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52
compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
View File

@ -1280,6 +1280,31 @@ fn prepare_struct_metadata(
// Tuples
//=-----------------------------------------------------------------------------
/// Returns names of captured upvars for closures and generators.
///
/// Here are some examples:
/// - `name__field1__field2` when the upvar is captured by value.
/// - `_ref__name__field` when the upvar is captured by reference.
fn closure_saved_names_of_captured_variables(tcx: TyCtxt<'tcx>, def_id: DefId) -> Vec<String> {
let body = tcx.optimized_mir(def_id);
body.var_debug_info
.iter()
.filter_map(|var| {
let is_ref = match var.value {
mir::VarDebugInfoContents::Place(place) if place.local == mir::Local::new(1) => {
// The projection is either `[.., Field, Deref]` or `[.., Field]`. It
// implies whether the variable is captured by value or by reference.
matches!(place.projection.last().unwrap(), mir::ProjectionElem::Deref)
}
_ => return None,
};
let prefix = if is_ref { "_ref__" } else { "" };
Some(prefix.to_owned() + &var.name.as_str())
})
.collect::<Vec<_>>()
}
/// Creates `MemberDescription`s for the fields of a tuple.
struct TupleMemberDescriptionFactory<'tcx> {
ty: Ty<'tcx>,
@ -1289,34 +1314,23 @@ struct TupleMemberDescriptionFactory<'tcx> {
impl<'tcx> TupleMemberDescriptionFactory<'tcx> {
fn create_member_descriptions(&self, cx: &CodegenCx<'ll, 'tcx>) -> Vec<MemberDescription<'ll>> {
// For closures and generators, name the captured upvars
// with the help of `CapturedPlace::to_mangled_name`.
let closure_def_id = match *self.ty.kind() {
ty::Generator(def_id, ..) => def_id.as_local(),
ty::Closure(def_id, ..) => def_id.as_local(),
_ => None,
};
let captures = match closure_def_id {
Some(local_def_id) => {
let typeck_results = cx.tcx.typeck(local_def_id);
let captures = typeck_results
.closure_min_captures_flattened(local_def_id.to_def_id())
.collect::<Vec<_>>();
Some(captures)
let capture_names = match *self.ty.kind() {
ty::Generator(def_id, ..) | ty::Closure(def_id, ..) => {
Some(closure_saved_names_of_captured_variables(cx.tcx, def_id))
}
_ => None,
};
let layout = cx.layout_of(self.ty);
self.component_types
.iter()
.enumerate()
.map(|(i, &component_type)| {
let (size, align) = cx.size_and_align_of(component_type);
let name = captures
.as_ref()
.map(|c| c[i].to_mangled_name(cx.tcx))
.unwrap_or_else(|| format!("__{}", i));
let name = if let Some(names) = capture_names.as_ref() {
names[i].clone()
} else {
format!("__{}", i)
};
MemberDescription {
name,
type_metadata: type_metadata(cx, component_type, self.span),

35
compiler/rustc_middle/src/ty/closure.rs
View File

@ -3,10 +3,12 @@
};
use crate::{mir, ty};
use std::fmt::Write;
use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_span::Span;
use rustc_span::{Span, Symbol};
use super::{Ty, TyCtxt};
@ -159,37 +161,26 @@ pub fn to_string(&self, tcx: TyCtxt<'tcx>) -> String {
place_to_string_for_capture(tcx, &self.place)
}
/// Returns mangled names of captured upvars. Here are some examples:
/// - `_captured_val__name__field`
/// - `_captured_ref__name__field`
///
/// The purpose is to use those names in debuginfo. They should be human-understandable.
/// Without the names, the end users may get confused when the debuggers just print some
/// pointers in closures or generators.
pub fn to_mangled_name(&self, tcx: TyCtxt<'tcx>) -> String {
let prefix = match self.info.capture_kind {
ty::UpvarCapture::ByValue(_) => "_captured_val__",
ty::UpvarCapture::ByRef(_) => "_captured_ref__",
};
/// Returns a symbol of the captured upvar, which looks like `name__field1__field2`.
pub fn to_symbol(&self, tcx: TyCtxt<'tcx>) -> Symbol {
let hir_id = match self.place.base {
HirPlaceBase::Upvar(upvar_id) => upvar_id.var_path.hir_id,
base => bug!("Expected an upvar, found {:?}", base),
};
let name = tcx.hir().name(hir_id);
let mut symbol = tcx.hir().name(hir_id).as_str().to_string();
let mut ty = self.place.base_ty;
let mut fields = String::new();
for proj in self.place.projections.iter() {
match proj.kind {
HirProjectionKind::Field(idx, variant) => match ty.kind() {
ty::Tuple(_) => fields = format!("{}__{}", fields, idx),
ty::Tuple(_) => write!(&mut symbol, "__{}", idx).unwrap(),
ty::Adt(def, ..) => {
fields = format!(
"{}__{}",
fields,
write!(
&mut symbol,
"__{}",
def.variants[variant].fields[idx as usize].ident.name.as_str(),
);
)
.unwrap();
}
ty => {
bug!("Unexpected type {:?} for `Field` projection", ty)
@ -204,7 +195,7 @@ pub fn to_mangled_name(&self, tcx: TyCtxt<'tcx>) -> String {
ty = proj.ty;
}
prefix.to_owned() + &name.to_string() + &fields
Symbol::intern(&symbol)
}
/// Returns the hir-id of the root variable for the captured place.

10
compiler/rustc_mir_build/src/build/mod.rs
View File

@ -16,7 +16,7 @@
use rustc_middle::thir::{BindingMode, Expr, ExprId, LintLevel, PatKind, Thir};
use rustc_middle::ty::subst::Subst;
use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeckResults};
use rustc_span::symbol::{kw, sym};
use rustc_span::symbol::sym;
use rustc_span::Span;
use rustc_target::spec::abi::Abi;
use rustc_target::spec::PanicStrategy;
@ -974,13 +974,7 @@ fn args_and_body(
let mutability = captured_place.mutability;
// FIXME(project-rfc-2229#8): Store more precise information
let mut name = kw::Empty;
if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
name = ident.name;
}
}
let name = captured_place.to_symbol(tcx);
let mut projs = closure_env_projs.clone();
projs.push(ProjectionElem::Field(Field::new(i), ty));

32
src/test/debuginfo/captured-fields.rs → src/test/debuginfo/captured-fields-1.rs
View File

@ -4,38 +4,44 @@
// gdb-command:run
// gdb-command:print test
// gdbr-check:$1 = captured_fields::main::{closure#0} {_captured_ref__my_ref__my_field1: 0x[...]}
// gdbr-check:$1 = captured_fields_1::main::{closure#0} {_ref__my_ref__my_field1: 0x[...]}
// gdb-command:continue
// gdb-command:print test
// gdbr-check:$2 = captured_fields::main::{closure#1} {_captured_ref__my_ref__my_field2: 0x[...]}
// gdbr-check:$2 = captured_fields_1::main::{closure#1} {_ref__my_ref__my_field2: 0x[...]}
// gdb-command:continue
// gdb-command:print test
// gdbr-check:$3 = captured_fields::main::{closure#2} {_captured_ref__my_ref: 0x[...]}
// gdbr-check:$3 = captured_fields_1::main::{closure#2} {_ref__my_ref: 0x[...]}
// gdb-command:continue
// gdb-command:print test
// gdbr-check:$4 = captured_fields::main::{closure#3} {_captured_val__my_ref: 0x[...]}
// gdbr-check:$4 = captured_fields_1::main::{closure#3} {my_ref: 0x[...]}
// gdb-command:continue
// gdb-command:print test
// gdbr-check:$5 = captured_fields::main::{closure#4} {_captured_val__my_var: captured_fields::MyStruct {my_field1: 11, my_field2: 22}}
// gdbr-check:$5 = captured_fields_1::main::{closure#4} {my_var__my_field2: 22}
// gdb-command:continue
// gdb-command:print test
// gdbr-check:$6 = captured_fields_1::main::{closure#5} {my_var: captured_fields_1::MyStruct {my_field1: 11, my_field2: 22}}
// gdb-command:continue
// === LLDB TESTS ==================================================================================
// lldb-command:run
// lldb-command:print test
// lldbg-check:(captured_fields::main::{closure#0}) $0 = { _captured_ref__my_ref__my_field1 = 0x[...] }
// lldbg-check:(captured_fields_1::main::{closure#0}) $0 = { _ref__my_ref__my_field1 = 0x[...] }
// lldb-command:continue
// lldb-command:print test
// lldbg-check:(captured_fields::main::{closure#1}) $1 = { _captured_ref__my_ref__my_field2 = 0x[...] }
// lldbg-check:(captured_fields_1::main::{closure#1}) $1 = { _ref__my_ref__my_field2 = 0x[...] }
// lldb-command:continue
// lldb-command:print test
// lldbg-check:(captured_fields::main::{closure#2}) $2 = { _captured_ref__my_ref = 0x[...] }
// lldbg-check:(captured_fields_1::main::{closure#2}) $2 = { _ref__my_ref = 0x[...] }
// lldb-command:continue
// lldb-command:print test
// lldbg-check:(captured_fields::main::{closure#3}) $3 = { _captured_val__my_ref = 0x[...] }
// lldbg-check:(captured_fields_1::main::{closure#3}) $3 = { my_ref = 0x[...] }
// lldb-command:continue
// lldb-command:print test
// lldbg-check:(captured_fields::main::{closure#4}) $4 = { _captured_val__my_var = { my_field1 = 11 my_field2 = 22 } }
// lldbg-check:(captured_fields_1::main::{closure#4}) $4 = { my_var__my_field2 = 22 }
// lldb-command:continue
// lldb-command:print test
// lldbg-check:(captured_fields_1::main::{closure#5}) $5 = { my_var = { my_field1 = 11 my_field2 = 22 } }
// lldb-command:continue
#![feature(capture_disjoint_fields)]
@ -77,6 +83,12 @@ fn main() {
_zzz(); // #break
let test = move || {
let a = my_var.my_field2;
};
_zzz(); // #break
let test = || {
let a = my_var;
};

55
src/test/debuginfo/captured-fields-2.rs Normal file
View File

@ -0,0 +1,55 @@
// compile-flags:-g
// === GDB TESTS ===================================================================================
// gdb-command:run
// gdb-command:print my_ref__my_field1
// gdbr-check:$1 = 11
// gdb-command:continue
// gdb-command:print my_var__my_field2
// gdbr-check:$2 = 22
// gdb-command:continue
// === LLDB TESTS ==================================================================================
// lldb-command:run
// lldb-command:print my_ref__my_field1
// lldbg-check:(unsigned int) $0 = 11
// lldb-command:continue
// lldb-command:print my_var__my_field2
// lldbg-check:(unsigned int) $1 = 22
// lldb-command:continue
#![feature(capture_disjoint_fields)]
#![allow(unused)]
struct MyStruct {
my_field1: u32,
my_field2: u32,
}
fn main() {
let mut my_var = MyStruct {
my_field1: 11,
my_field2: 22,
};
let my_ref = &mut my_var;
let test = || {
let a = my_ref.my_field1;
_zzz(); // #break
};
test();
let test = move || {
let a = my_var.my_field2;
_zzz(); // #break
};
test();
}
fn _zzz() {}

8
src/test/debuginfo/generator-objects.rs
View File

@ -11,16 +11,16 @@
// gdb-command:run
// gdb-command:print b
// gdb-check:$1 = generator_objects::main::{generator#0}::Unresumed{_captured_ref__a: 0x[...]}
// gdb-check:$1 = generator_objects::main::{generator#0}::Unresumed{_ref__a: 0x[...]}
// gdb-command:continue
// gdb-command:print b
// gdb-check:$2 = generator_objects::main::{generator#0}::Suspend0{c: 6, d: 7, _captured_ref__a: 0x[...]}
// gdb-check:$2 = generator_objects::main::{generator#0}::Suspend0{c: 6, d: 7, _ref__a: 0x[...]}
// gdb-command:continue
// gdb-command:print b
// gdb-check:$3 = generator_objects::main::{generator#0}::Suspend1{c: 7, d: 8, _captured_ref__a: 0x[...]}
// gdb-check:$3 = generator_objects::main::{generator#0}::Suspend1{c: 7, d: 8, _ref__a: 0x[...]}
// gdb-command:continue
// gdb-command:print b
// gdb-check:$4 = generator_objects::main::{generator#0}::Returned{_captured_ref__a: 0x[...]}
// gdb-check:$4 = generator_objects::main::{generator#0}::Returned{_ref__a: 0x[...]}
// === LLDB TESTS ==================================================================================

6
src/test/debuginfo/issue-57822.rs
View File

@ -11,17 +11,17 @@
// gdb-command:run
// gdb-command:print g
// gdb-check:$1 = issue_57822::main::{closure#1} {_captured_val__f: issue_57822::main::{closure#0} {_captured_val__x: 1}}
// gdb-check:$1 = issue_57822::main::{closure#1} {f: issue_57822::main::{closure#0} {x: 1}}
// gdb-command:print b
// gdb-check:$2 = issue_57822::main::{generator#3}::Unresumed{_captured_val__a: issue_57822::main::{generator#2}::Unresumed{_captured_val__y: 2}}
// gdb-check:$2 = issue_57822::main::{generator#3}::Unresumed{a: issue_57822::main::{generator#2}::Unresumed{y: 2}}
// === LLDB TESTS ==================================================================================
// lldb-command:run
// lldb-command:print g
// lldbg-check:(issue_57822::main::{closure#1}) $0 = { _captured_val__f = { _captured_val__x = 1 } }
// lldbg-check:(issue_57822::main::{closure#1}) $0 = { f = { x = 1 } }
// lldb-command:print b
// lldbg-check:(issue_57822::main::{generator#3}) $1 =