Auto merge of #120845 - petrochenkov:debmac, r=oli-obk

debuginfo: Stabilize `-Z debug-macros`, `-Z collapse-macro-debuginfo` and `#[collapse_debuginfo]`

`-Z debug-macros` is "stabilized" by enabling it by default and removing.

`-Z collapse-macro-debuginfo` is stabilized as `-C collapse-macro-debuginfo`.
It now supports all typical boolean values (`parse_opt_bool`) in addition to just yes/no.

Default value of `collapse_debuginfo` was changed from `false` to `external` (i.e. collapsed if external, not collapsed if local) - https://github.com/rust-lang/rust/issues/100758#issuecomment-1935815625 describes some debugging scenarios that motivate this default as reasonable.
`#[collapse_debuginfo]` attribute without a value is no longer supported to avoid guessing the default.

Stabilization report: https://github.com/rust-lang/rust/pull/120845#issuecomment-1939145242

Closes https://github.com/rust-lang/rust/issues/100758
Closes https://github.com/rust-lang/rust/issues/41743
Closes https://github.com/rust-lang/rust/issues/39153

1 files changed, 3 insertions, 19 deletions

diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index a5fd82a3054..d0e2fc2de12 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -4,13 +4,12 @@ use rustc_index::IndexVec;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir;
 use rustc_middle::ty;
-use rustc_middle::ty::layout::TyAndLayout;
-use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
+use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
 use rustc_middle::ty::Instance;
 use rustc_middle::ty::Ty;
 use rustc_session::config::DebugInfo;
 use rustc_span::symbol::{kw, Symbol};
-use rustc_span::{BytePos, Span};
+use rustc_span::{hygiene, BytePos, Span};
 use rustc_target::abi::{Abi, FieldIdx, FieldsShape, Size, VariantIdx};
 
 use super::operand::{OperandRef, OperandValue};
@@ -220,26 +219,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         &self,
         source_info: mir::SourceInfo,
     ) -> Option<(Bx::DIScope, Option<Bx::DILocation>, Span)> {
-        let span = self.adjust_span_for_debugging(source_info.span);
         let scope = &self.debug_context.as_ref()?.scopes[source_info.scope];
+        let span = hygiene::walk_chain_collapsed(source_info.span, self.mir.span);
         Some((scope.adjust_dbg_scope_for_span(self.cx, span), scope.inlined_at, span))
     }
 
-    /// In order to have a good line stepping behavior in debugger, we overwrite debug
-    /// locations of macro expansions with that of the outermost expansion site (when the macro is
-    /// annotated with `#[collapse_debuginfo]` or when `-Zdebug-macros` is provided).
-    fn adjust_span_for_debugging(&self, span: Span) -> Span {
-        // Bail out if debug info emission is not enabled.
-        if self.debug_context.is_none() {
-            return span;
-        }
-        // Walk up the macro expansion chain until we reach a non-expanded span.
-        // We also stop at the function body level because no line stepping can occur
-        // at the level above that.
-        // Use span of the outermost expansion site, while keeping the original lexical scope.
-        self.cx.tcx().collapsed_debuginfo(span, self.mir.span)
-    }
-
     fn spill_operand_to_stack(
         operand: OperandRef<'tcx, Bx::Value>,
         name: Option<String>,