Rollup merge of rust-lang#69667 - JohnTitor:no-debug, r=nikomatsakis

Remove the `no_debug` feature

Context: rust-lang#29721 (comment)

r? @nikomatsakis

Author: Centril

src/librustc/middle/codegen_fn_attrs.rs

@@ -58,9 +58,6 @@ bitflags! {
         /// "weird symbol" for the standard library in that it has slightly
         /// different linkage, visibility, and reachability rules.
         const RUSTC_STD_INTERNAL_SYMBOL = 1 << 6;
-        /// `#[no_debug]`: an indicator that no debugging information should be
-        /// generated for this function by LLVM.
-        const NO_DEBUG                  = 1 << 7;
         /// `#[thread_local]`: indicates a static is actually a thread local
         /// piece of memory
         const THREAD_LOCAL              = 1 << 8;

src/librustc_codegen_llvm/debuginfo/metadata.rs

@@ -2269,10 +2269,6 @@ pub fn create_global_var_metadata(cx: &CodegenCx<'ll, '_>, def_id: DefId, global
     let tcx = cx.tcx;
     let attrs = tcx.codegen_fn_attrs(def_id);
 
-    if attrs.flags.contains(CodegenFnAttrFlags::NO_DEBUG) {
-        return;
-    }
-
     let no_mangle = attrs.flags.contains(CodegenFnAttrFlags::NO_MANGLE);
     // We may want to remove the namespace scope if we're in an extern block (see
     // https://github.com/rust-lang/rust/pull/46457#issuecomment-351750952).

src/librustc_codegen_llvm/debuginfo/mod.rs

@@ -12,7 +12,6 @@ use crate::llvm;
 use crate::llvm::debuginfo::{
     DIArray, DIBuilder, DIFile, DIFlags, DILexicalBlock, DISPFlags, DIScope, DIType, DIVariable,
 };
-use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LOCAL_CRATE};
 
@@ -22,7 +21,7 @@ use crate::common::CodegenCx;
 use crate::value::Value;
 use rustc::mir;
 use rustc::session::config::{self, DebugInfo};
-use rustc::ty::{self, Instance, InstanceDef, ParamEnv, Ty};
+use rustc::ty::{self, Instance, ParamEnv, Ty};
 use rustc_codegen_ssa::debuginfo::type_names;
 use rustc_codegen_ssa::mir::debuginfo::{DebugScope, FunctionDebugContext, VariableKind};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -241,12 +240,6 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             return None;
         }
 
-        if let InstanceDef::Item(def_id) = instance.def {
-            if self.tcx().codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::NO_DEBUG) {
-                return None;
-            }
-        }
-
         let span = mir.span;
 
         // This can be the case for functions inlined from another crate

src/librustc_feature/active.rs

@@ -289,9 +289,6 @@ declare_features! (
     /// Permits specifying whether a function should permit unwinding or abort on unwind.
     (active, unwind_attributes, "1.4.0", Some(58760), None),
 
-    /// Allows `#[no_debug]`.
-    (active, no_debug, "1.5.0", Some(29721), None),
-
     /// Allows attributes on expressions and non-item statements.
     (active, stmt_expr_attributes, "1.6.0", Some(15701), None),
 

src/librustc_feature/builtin_attrs.rs

@@ -507,16 +507,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
             cfg_fn!(rustc_attrs),
         ),
     ),
-    (
-        sym::no_debug, Whitelisted, template!(Word),
-        Gated(
-            Stability::Deprecated("https://github.com/rust-lang/rust/issues/29721", None),
-            sym::no_debug,
-            "the `#[no_debug]` attribute was an experimental feature that has been \
-            deprecated due to lack of demand",
-            cfg_fn!(no_debug)
-        )
-    ),
     gated!(
         // Used in resolve:
         prelude_import, Whitelisted, template!(Word),

src/librustc_feature/removed.rs

@@ -111,6 +111,8 @@ declare_features! (
     /// Allows overlapping impls of marker traits.
     (removed, overlapping_marker_traits, "1.42.0", Some(29864), None,
      Some("removed in favor of `#![feature(marker_trait_attr)]`")),
+    /// Allows `#[no_debug]`.
+    (removed, no_debug, "1.43.0", Some(29721), None, Some("removed due to lack of demand")),
     // -------------------------------------------------------------------------
     // feature-group-end: removed features
     // -------------------------------------------------------------------------

src/librustc_typeck/collect.rs

@@ -2341,8 +2341,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
             codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
         } else if attr.check_name(sym::rustc_std_internal_symbol) {
             codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
-        } else if attr.check_name(sym::no_debug) {
-            codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_DEBUG;
         } else if attr.check_name(sym::used) {
             codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
         } else if attr.check_name(sym::thread_local) {

src/test/debuginfo/no-debug-attribute.rs

@@ -1,7 +1,6 @@
 // ignore-tidy-tab
 
 #![warn(unused_mut, unused_parens)] // UI tests pass `-A unused`—see Issue #43896
-#![feature(no_debug)]
 
 #[no_mangle] const DISCOVERY: usize = 1;
 //~^ ERROR const items should never be `#[no_mangle]`
@@ -39,9 +38,6 @@ struct Equinox {
     warp_factor: f32,
 }
 
-#[no_debug] // should suggest removal of deprecated attribute
-//~^ WARN deprecated
-//~| HELP remove this attribute
 fn main() {
     while true {
     //~^ WARN denote infinite loops

src/test/ui/feature-gates/feature-gate-no-debug-2.rs

@@ -1,13 +1,13 @@
 warning: denote infinite loops with `loop { ... }`
-  --> $DIR/suggestions.rs:46:5
+  --> $DIR/suggestions.rs:42:5
    |
 LL |     while true {
    |     ^^^^^^^^^^ help: use `loop`
    |
    = note: `#[warn(while_true)]` on by default
 
 warning: unnecessary parentheses around assigned value
-  --> $DIR/suggestions.rs:49:31
+  --> $DIR/suggestions.rs:45:31
    |
 LL |         let mut registry_no = (format!("NX-{}", 74205));
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
@@ -18,16 +18,8 @@ note: the lint level is defined here
 LL | #![warn(unused_mut, unused_parens)] // UI tests pass `-A unused`—see Issue #43896
    |                     ^^^^^^^^^^^^^
 
-warning: use of deprecated attribute `no_debug`: the `#[no_debug]` attribute was an experimental feature that has been deprecated due to lack of demand. See https://github.com/rust-lang/rust/issues/29721
-  --> $DIR/suggestions.rs:42:1
-   |
-LL | #[no_debug] // should suggest removal of deprecated attribute
-   | ^^^^^^^^^^^ help: remove this attribute
-   |
-   = note: `#[warn(deprecated)]` on by default
-
 warning: variable does not need to be mutable
-  --> $DIR/suggestions.rs:49:13
+  --> $DIR/suggestions.rs:45:13
    |
 LL |         let mut registry_no = (format!("NX-{}", 74205));
    |             ----^^^^^^^^^^^
@@ -41,7 +33,7 @@ LL | #![warn(unused_mut, unused_parens)] // UI tests pass `-A unused`—see Issu
    |         ^^^^^^^^^^
 
 warning: variable does not need to be mutable
-  --> $DIR/suggestions.rs:55:13
+  --> $DIR/suggestions.rs:51:13
    |
 LL |            let mut
    |   _____________^
@@ -53,7 +45,7 @@ LL | ||             b = 1;
    |               help: remove this `mut`
 
 error: const items should never be `#[no_mangle]`
-  --> $DIR/suggestions.rs:6:14
+  --> $DIR/suggestions.rs:5:14
    |
 LL | #[no_mangle] const DISCOVERY: usize = 1;
    |              -----^^^^^^^^^^^^^^^^^^^^^^
@@ -63,7 +55,7 @@ LL | #[no_mangle] const DISCOVERY: usize = 1;
    = note: `#[deny(no_mangle_const_items)]` on by default
 
 warning: functions generic over types or consts must be mangled
-  --> $DIR/suggestions.rs:12:1
+  --> $DIR/suggestions.rs:11:1
    |
 LL | #[no_mangle]
    | ------------ help: remove this attribute
@@ -74,39 +66,39 @@ LL | pub fn defiant<T>(_t: T) {}
    = note: `#[warn(no_mangle_generic_items)]` on by default
 
 warning: the `warp_factor:` in this pattern is redundant
-  --> $DIR/suggestions.rs:61:23
+  --> $DIR/suggestions.rs:57:23
    |
 LL |             Equinox { warp_factor: warp_factor } => {}
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^ help: use shorthand field pattern: `warp_factor`
    |
    = note: `#[warn(non_shorthand_field_patterns)]` on by default
 
 error: const items should never be `#[no_mangle]`
-  --> $DIR/suggestions.rs:22:18
+  --> $DIR/suggestions.rs:21:18
    |
 LL |     #[no_mangle] pub const DAUNTLESS: bool = true;
    |                  ---------^^^^^^^^^^^^^^^^^^^^^^^^
    |                  |
    |                  help: try a static value: `pub static`
 
 warning: functions generic over types or consts must be mangled
-  --> $DIR/suggestions.rs:25:18
+  --> $DIR/suggestions.rs:24:18
    |
 LL |     #[no_mangle] pub fn val_jean<T>() {}
    |     ------------ ^^^^^^^^^^^^^^^^^^^^^^^
    |     |
    |     help: remove this attribute
 
 error: const items should never be `#[no_mangle]`
-  --> $DIR/suggestions.rs:30:18
+  --> $DIR/suggestions.rs:29:18
    |
 LL |     #[no_mangle] pub(crate) const VETAR: bool = true;
    |                  ----------------^^^^^^^^^^^^^^^^^^^^
    |                  |
    |                  help: try a static value: `pub static`
 
 warning: functions generic over types or consts must be mangled
-  --> $DIR/suggestions.rs:33:18
+  --> $DIR/suggestions.rs:32:18
    |
 LL |     #[no_mangle] pub(crate) fn crossfield<T>() {}
    |     ------------ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^