Revert "Preserve the .debug_gdb_scripts section"

This reverts commit 868bdde25b.

compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs

@@ -1,7 +1,5 @@
 // .debug_gdb_scripts binary section.
 
-use std::ffi::CString;
-
 use rustc_codegen_ssa::base::collect_debugger_visualizers_transitive;
 use rustc_codegen_ssa::traits::*;
 use rustc_hir::def_id::LOCAL_CRATE;
@@ -33,12 +31,7 @@ pub(crate) fn insert_reference_to_gdb_debug_scripts_section_global(bx: &mut Buil
 pub(crate) fn get_or_insert_gdb_debug_scripts_section_global<'ll>(
     cx: &CodegenCx<'ll, '_>,
 ) -> &'ll Value {
-    let c_section_var_name = CString::new(format!(
-        "__rustc_debug_gdb_scripts_section_{}_{:08x}",
-        cx.tcx.crate_name(LOCAL_CRATE),
-        cx.tcx.stable_crate_id(LOCAL_CRATE),
-    ))
-    .unwrap();
+    let c_section_var_name = c"__rustc_debug_gdb_scripts_section__";
     let section_var_name = c_section_var_name.to_str().unwrap();
 
     let section_var = unsafe { llvm::LLVMGetNamedGlobal(cx.llmod, c_section_var_name.as_ptr()) };
@@ -91,10 +84,17 @@ pub(crate) fn get_or_insert_gdb_debug_scripts_section_global<'ll>(
 }
 
 pub(crate) fn needs_gdb_debug_scripts_section(cx: &CodegenCx<'_, '_>) -> bool {
-    // We collect pretty printers transitively for all crates, so we make sure
-    // that the section is only emitted for leaf crates.
+    // To ensure the section `__rustc_debug_gdb_scripts_section__` will not create
+    // ODR violations at link time, this section will not be emitted for rlibs since
+    // each rlib could produce a different set of visualizers that would be embedded
+    // in the `.debug_gdb_scripts` section. For that reason, we make sure that the
+    // section is only emitted for leaf crates.
     let embed_visualizers = cx.tcx.crate_types().iter().any(|&crate_type| match crate_type {
-        CrateType::Executable | CrateType::Cdylib | CrateType::Staticlib | CrateType::Sdylib => {
+        CrateType::Executable
+        | CrateType::Dylib
+        | CrateType::Cdylib
+        | CrateType::Staticlib
+        | CrateType::Sdylib => {
             // These are crate types for which we will embed pretty printers since they
             // are treated as leaf crates.
             true
@@ -105,11 +105,9 @@ pub(crate) fn needs_gdb_debug_scripts_section(cx: &CodegenCx<'_, '_>) -> bool {
             // want to slow down the common case.
             false
         }
-        CrateType::Rlib | CrateType::Dylib => {
-            // Don't embed pretty printers for these crate types; the compiler
-            // can see the `#[debug_visualizer]` attributes when using the
-            // library, and emitting `.debug_gdb_scripts` regardless would
-            // break `#![omit_gdb_pretty_printer_section]`.
+        CrateType::Rlib => {
+            // As per the above description, embedding pretty printers for rlibs could
+            // lead to ODR violations so we skip this crate type as well.
             false
         }
     });

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -30,7 +30,7 @@ use tracing::debug;
 
 use self::metadata::{UNKNOWN_COLUMN_NUMBER, UNKNOWN_LINE_NUMBER, file_metadata, type_di_node};
 use self::namespace::mangled_name_of_instance;
-use self::utils::{DIB, create_DIArray, debug_context, is_node_local_to_unit};
+use self::utils::{DIB, create_DIArray, is_node_local_to_unit};
 use crate::builder::Builder;
 use crate::common::{AsCCharPtr, CodegenCx};
 use crate::llvm;
@@ -131,28 +131,20 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
 }
 
 /// Creates any deferred debug metadata nodes
-pub(crate) fn finalize(cx: &mut CodegenCx<'_, '_>) {
-    if cx.dbg_cx.is_none() {
-        return;
+pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
+    if let Some(dbg_cx) = &cx.dbg_cx {
+        debug!("finalize");
+
+        if gdb::needs_gdb_debug_scripts_section(cx) {
+            // Add a .debug_gdb_scripts section to this compile-unit. This will
+            // cause GDB to try and load the gdb_load_rust_pretty_printers.py file,
+            // which activates the Rust pretty printers for binary this section is
+            // contained in.
+            gdb::get_or_insert_gdb_debug_scripts_section_global(cx);
+        }
+
+        dbg_cx.finalize(cx.sess());
     }
-
-    debug!("finalize");
-
-    if gdb::needs_gdb_debug_scripts_section(cx) {
-        // Add a .debug_gdb_scripts section to this compile-unit. This will
-        // cause GDB to try and load the gdb_load_rust_pretty_printers.py file,
-        // which activates the Rust pretty printers for binary this section is
-        // contained in.
-        let section_var = gdb::get_or_insert_gdb_debug_scripts_section_global(cx);
-
-        // Make sure that the linker doesn't optimize the global away. Adding
-        // it to `llvm.used` has the advantage that it works even in no_std
-        // binaries, where we don't have a main shim and thus don't emit a
-        // volatile load to preserve the global.
-        cx.add_used_global(section_var);
-    }
-
-    debug_context(cx).finalize(cx.sess());
 }
 
 impl<'ll> Builder<'_, 'll, '_> {
@@ -622,7 +614,7 @@ impl<'ll, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         metadata::extend_scope_to_file(self, scope_metadata, file)
     }
 
-    fn debuginfo_finalize(&mut self) {
+    fn debuginfo_finalize(&self) {
         finalize(self)
     }