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Factor out debuginfo offset calculation

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This commit is contained in:
Wesley Wiser 2022-12-07 12:51:07 -05:00
parent 34246f89e2
commit 525d0dd6e2
1 changed files with 49 additions and 27 deletions
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76
compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
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@ -76,6 +76,53 @@ impl<'tcx, S: Copy, L: Copy> DebugScope<S, L> {
}
}
struct DebugInfoOffset<T> {
/// Offset from the `base` used to calculate the debuginfo offset.
direct_offset: Size,
/// Each offset in this vector indicates one level of indirection from the base or previous
/// indirect offset plus a dereference.
indirect_offsets: Vec<Size>,
/// The final location debuginfo should point to.
result: T,
}
fn calculate_debuginfo_offset<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
local: mir::Local,
var: &PerLocalVarDebugInfo<'tcx, Bx::DIVariable>,
base: PlaceRef<'tcx, Bx::Value>,
) -> DebugInfoOffset<PlaceRef<'tcx, Bx::Value>> {
let mut direct_offset = Size::ZERO;
// FIXME(eddyb) use smallvec here.
let mut indirect_offsets = vec![];
let mut place = base;
for elem in &var.projection[..] {
match *elem {
mir::ProjectionElem::Deref => {
indirect_offsets.push(Size::ZERO);
place = bx.load_operand(place).deref(bx.cx());
}
mir::ProjectionElem::Field(field, _) => {
let i = field.index();
let offset = indirect_offsets.last_mut().unwrap_or(&mut direct_offset);
*offset += place.layout.fields.offset(i);
place = place.project_field(bx, i);
}
mir::ProjectionElem::Downcast(_, variant) => {
place = place.project_downcast(bx, variant);
}
_ => span_bug!(
var.source_info.span,
"unsupported var debuginfo place `{:?}`",
mir::Place { local, projection: var.projection },
),
}
}
DebugInfoOffset { direct_offset, indirect_offsets, result: place }
}
impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
pub fn set_debug_loc(&self, bx: &mut Bx, source_info: mir::SourceInfo) {
bx.set_span(source_info.span);
@ -262,33 +309,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let Some(dbg_var) = var.dbg_var else { continue };
let Some(dbg_loc) = self.dbg_loc(var.source_info) else { continue };
let mut direct_offset = Size::ZERO;
// FIXME(eddyb) use smallvec here.
let mut indirect_offsets = vec![];
let mut place = base;
for elem in &var.projection[..] {
match *elem {
mir::ProjectionElem::Deref => {
indirect_offsets.push(Size::ZERO);
place = bx.load_operand(place).deref(bx.cx());
}
mir::ProjectionElem::Field(field, _) => {
let i = field.index();
let offset = indirect_offsets.last_mut().unwrap_or(&mut direct_offset);
*offset += place.layout.fields.offset(i);
place = place.project_field(bx, i);
}
mir::ProjectionElem::Downcast(_, variant) => {
place = place.project_downcast(bx, variant);
}
_ => span_bug!(
var.source_info.span,
"unsupported var debuginfo place `{:?}`",
mir::Place { local, projection: var.projection },
),
}
}
let DebugInfoOffset { direct_offset, indirect_offsets, result: place } =
calculate_debuginfo_offset(bx, local, &var, base);
// When targeting MSVC, create extra allocas for arguments instead of pointing multiple
// dbg_var_addr() calls into the same alloca with offsets. MSVC uses CodeView records