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rustc_codegen_ssa: convert mir::VarDebugInfo into a custom PerLocalVa…
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…rDebugInfo.
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@eddyb
eddyb committed Jan 29, 2020
1 parent ab946df commit f397140
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Showing 2 changed files with 133 additions and 54 deletions.
174 changes: 125 additions & 49 deletions src/librustc_codegen_ssa/mir/debuginfo.rs
View file
Original file line number Diff line number Diff line change
@@ -1,12 +1,12 @@
use crate::traits::*;
use rustc::mir;
use rustc::session::config::DebugInfo;
use rustc::ty;
use rustc::ty::layout::{LayoutOf, Size};
use rustc::ty::TyCtxt;
use rustc_hir::def_id::CrateNum;
use rustc_index::vec::IndexVec;

use rustc_span::symbol::kw;
use rustc_span::symbol::{kw, Symbol};
use rustc_span::{BytePos, Span};

use super::OperandValue;
Expand All @@ -24,6 +24,19 @@ pub enum VariableKind {
LocalVariable,
}

/// Like `mir::VarDebugInfo`, but within a `mir::Local`.
#[derive(Copy, Clone)]
pub struct PerLocalVarDebugInfo<'tcx, D> {
pub name: Symbol,
pub source_info: mir::SourceInfo,

/// `DIVariable` returned by `create_dbg_var`.
pub dbg_var: Option<D>,

/// `.place.projection` from `mir::VarDebugInfo`.
pub projection: &'tcx ty::List<mir::PlaceElem<'tcx>>,
}

#[derive(Clone, Copy, Debug)]
pub struct DebugScope<D> {
pub scope_metadata: Option<D>,
Expand Down Expand Up @@ -103,6 +116,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
// FIXME(eddyb) use `llvm.dbg.value` (which would work for operands),
// not just `llvm.dbg.declare` (which requires `alloca`).
pub fn debug_introduce_local(&self, bx: &mut Bx, local: mir::Local) {
let full_debug_info = bx.sess().opts.debuginfo == DebugInfo::Full;

// FIXME(eddyb) maybe name the return place as `_0` or `return`?
if local == mir::RETURN_PLACE {
return;
Expand All @@ -112,35 +127,63 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
Some(per_local) => &per_local[local],
None => return,
};
let whole_local_var = vars.iter().copied().find(|var| var.place.projection.is_empty());
let has_proj = || vars.iter().any(|var| !var.place.projection.is_empty());
let whole_local_var = vars.iter().find(|var| var.projection.is_empty()).copied();
let has_proj = || vars.iter().any(|var| !var.projection.is_empty());

let (fallback_var, kind) = if self.mir.local_kind(local) == mir::LocalKind::Arg {
let fallback_var = if self.mir.local_kind(local) == mir::LocalKind::Arg {
let arg_index = local.index() - 1;

// Add debuginfo even to unnamed arguments.
// FIXME(eddyb) is this really needed?
let var = if arg_index == 0 && has_proj() {
if arg_index == 0 && has_proj() {
// Hide closure environments from debuginfo.
// FIXME(eddyb) shouldn't `ArgumentVariable` indices
// be offset to account for the hidden environment?
None
} else if whole_local_var.is_some() {
// No need to make up anything, there is a `mir::VarDebugInfo`
// covering the whole local.
// FIXME(eddyb) take `whole_local_var.source_info.scope` into
// account, just in case it doesn't use `ArgumentVariable`
// (after #67586 gets fixed).
None
} else {
Some(mir::VarDebugInfo {
name: kw::Invalid,
source_info: self.mir.local_decls[local].source_info,
place: local.into(),
let name = kw::Invalid;
let decl = &self.mir.local_decls[local];
let (scope, span) = if full_debug_info {
self.debug_loc(decl.source_info)
} else {
(None, decl.source_info.span)
};
let dbg_var = scope.map(|scope| {
// FIXME(eddyb) is this `+ 1` needed at all?
let kind = VariableKind::ArgumentVariable(arg_index + 1);

self.cx.create_dbg_var(
self.debug_context.as_ref().unwrap(),
name,
self.monomorphize(&decl.ty),
scope,
kind,
span,
)
});

Some(PerLocalVarDebugInfo {
name,
source_info: decl.source_info,
dbg_var,
projection: ty::List::empty(),
})
};
(var, VariableKind::ArgumentVariable(arg_index + 1))
}
} else {
(None, VariableKind::LocalVariable)
None
};

let local_ref = &self.locals[local];

if !bx.sess().fewer_names() {
let name = match whole_local_var.or(fallback_var.as_ref()) {
let name = match whole_local_var.or(fallback_var) {
Some(var) if var.name != kw::Invalid => var.name.to_string(),
_ => format!("{:?}", local),
};
Expand All @@ -163,7 +206,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
}
}

if bx.sess().opts.debuginfo != DebugInfo::Full {
if !full_debug_info {
return;
}

Expand All @@ -178,22 +221,15 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
_ => return,
};

let vars = vars.iter().copied().chain(if whole_local_var.is_none() {
fallback_var.as_ref()
} else {
None
});
let vars = vars.iter().copied().chain(fallback_var);

for var in vars {
let mut layout = base.layout;
let mut direct_offset = Size::ZERO;
// FIXME(eddyb) use smallvec here.
let mut indirect_offsets = vec![];

let kind =
if var.place.projection.is_empty() { kind } else { VariableKind::LocalVariable };

for elem in &var.place.projection[..] {
for elem in &var.projection[..] {
match *elem {
mir::ProjectionElem::Deref => {
indirect_offsets.push(Size::ZERO);
Expand All @@ -202,7 +238,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
.ty
.builtin_deref(true)
.unwrap_or_else(|| {
span_bug!(var.source_info.span, "cannot deref `{}`", layout.ty,)
span_bug!(var.source_info.span, "cannot deref `{}`", layout.ty)
})
.ty,
);
Expand All @@ -219,24 +255,24 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
_ => span_bug!(
var.source_info.span,
"unsupported var debuginfo place `{:?}`",
var.place,
mir::Place { local, projection: var.projection },
),
}
}

let (scope, span) = self.debug_loc(var.source_info);
if let Some(scope) = scope {
let dbg_var =
bx.create_dbg_var(debug_context, var.name, layout.ty, scope, kind, span);
bx.dbg_var_addr(
debug_context,
dbg_var,
scope,
base.llval,
direct_offset,
&indirect_offsets,
span,
);
if let Some(dbg_var) = var.dbg_var {
bx.dbg_var_addr(
debug_context,
dbg_var,
scope,
base.llval,
direct_offset,
&indirect_offsets,
span,
);
}
}
}
}
Expand All @@ -248,20 +284,60 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
}
}
}
}

/// Partition all `VarDebuginfo` in `body`, by their base `Local`.
pub fn per_local_var_debug_info(
tcx: TyCtxt<'tcx>,
body: &'a mir::Body<'tcx>,
) -> Option<IndexVec<mir::Local, Vec<&'a mir::VarDebugInfo<'tcx>>>> {
if tcx.sess.opts.debuginfo == DebugInfo::Full || !tcx.sess.fewer_names() {
let mut per_local = IndexVec::from_elem(vec![], &body.local_decls);
for var in &body.var_debug_info {
per_local[var.place.local].push(var);
/// Partition all `VarDebugInfo` in `self.mir`, by their base `Local`.
pub fn compute_per_local_var_debug_info(
&self,
) -> Option<IndexVec<mir::Local, Vec<PerLocalVarDebugInfo<'tcx, Bx::DIVariable>>>> {
let full_debug_info = self.cx.sess().opts.debuginfo == DebugInfo::Full;

if !(full_debug_info || !self.cx.sess().fewer_names()) {
return None;
}

let mut per_local = IndexVec::from_elem(vec![], &self.mir.local_decls);
for var in &self.mir.var_debug_info {
let (scope, span) = if full_debug_info {
self.debug_loc(var.source_info)
} else {
(None, var.source_info.span)
};
let dbg_var = scope.map(|scope| {
let place = var.place;
let var_ty = self.monomorphized_place_ty(place.as_ref());
let var_kind = if self.mir.local_kind(place.local) == mir::LocalKind::Arg
&& place.projection.is_empty()
{
// FIXME(eddyb, #67586) take `var.source_info.scope` into
// account to avoid using `ArgumentVariable` more than once
// per argument local.

let arg_index = place.local.index() - 1;

// FIXME(eddyb) shouldn't `ArgumentVariable` indices be
// offset in closures to account for the hidden environment?
// Also, is this `+ 1` needed at all?
VariableKind::ArgumentVariable(arg_index + 1)
} else {
VariableKind::LocalVariable
};
self.cx.create_dbg_var(
self.debug_context.as_ref().unwrap(),
var.name,
var_ty,
scope,
var_kind,
span,
)
});

per_local[var.place.local].push(PerLocalVarDebugInfo {
name: var.name,
source_info: var.source_info,
dbg_var,
projection: var.place.projection,
});
}
Some(per_local)
} else {
None
}
}
13 changes: 8 additions & 5 deletions src/librustc_codegen_ssa/mir/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ use rustc_index::bit_set::BitSet;
use rustc_index::vec::IndexVec;

use self::analyze::CleanupKind;
use self::debuginfo::FunctionDebugContext;
use self::debuginfo::{FunctionDebugContext, PerLocalVarDebugInfo};
use self::place::PlaceRef;
use rustc::mir::traversal;

Expand Down Expand Up @@ -74,9 +74,10 @@ pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
/// notably `expect`.
locals: IndexVec<mir::Local, LocalRef<'tcx, Bx::Value>>,

/// All `VarDebuginfo` from the MIR body, partitioned by `Local`.
/// This is `None` if no variable debuginfo/names are needed.
per_local_var_debug_info: Option<IndexVec<mir::Local, Vec<&'tcx mir::VarDebugInfo<'tcx>>>>,
/// All `VarDebugInfo` from the MIR body, partitioned by `Local`.
/// This is `None` if no var`#[non_exhaustive]`iable debuginfo/names are needed.
per_local_var_debug_info:
Option<IndexVec<mir::Local, Vec<PerLocalVarDebugInfo<'tcx, Bx::DIVariable>>>>,

/// Caller location propagated if this function has `#[track_caller]`.
caller_location: Option<OperandRef<'tcx, Bx::Value>>,
Expand Down Expand Up @@ -178,10 +179,12 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
funclets,
locals: IndexVec::new(),
debug_context,
per_local_var_debug_info: debuginfo::per_local_var_debug_info(cx.tcx(), mir_body),
per_local_var_debug_info: None,
caller_location: None,
};

fx.per_local_var_debug_info = fx.compute_per_local_var_debug_info();

let memory_locals = analyze::non_ssa_locals(&fx);

// Allocate variable and temp allocas
Expand Down

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