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Revert "Preserve the .debug_gdb_scripts section"

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This reverts commit 868bdde25b.
This commit is contained in:
bjorn3 2025-08-06 18:01:07 +00:00
parent 270c1a4d24
commit e02cc40ec9
8 changed files with 61 additions and 73 deletions
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3
compiler/rustc_codegen_gcc/src/debuginfo.rs
View file

@ -254,8 +254,7 @@ impl<'gcc, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
// TODO(antoyo): implement.
}
fn debuginfo_finalize(&mut self) {
// TODO: emit section `.debug_gdb_scripts`.
fn debuginfo_finalize(&self) {
self.context.set_debug_info(true)
}

12
compiler/rustc_codegen_llvm/src/base.rs
View file

@ -109,16 +109,11 @@ pub(crate) fn compile_codegen_unit(
}
// Finalize code coverage by injecting the coverage map. Note, the coverage map will
// also be added to the `llvm.compiler.used` variable, created below.
// also be added to the `llvm.compiler.used` variable, created next.
if cx.sess().instrument_coverage() {
cx.coverageinfo_finalize();
}
// Finalize debuginfo. This adds to `llvm.used`, created below.
if cx.sess().opts.debuginfo != DebugInfo::None {
cx.debuginfo_finalize();
}
// Create the llvm.used and llvm.compiler.used variables.
if !cx.used_statics.is_empty() {
cx.create_used_variable_impl(c"llvm.used", &cx.used_statics);
@ -135,6 +130,11 @@ pub(crate) fn compile_codegen_unit(
llvm::LLVMDeleteGlobal(old_g);
}
}
// Finalize debuginfo
if cx.sess().opts.debuginfo != DebugInfo::None {
cx.debuginfo_finalize();
}
}
ModuleCodegen::new_regular(cgu_name.to_string(), llvm_module)

30
compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs
View file

@ -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
}
});

38
compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
View file

@ -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)
}

10
compiler/rustc_codegen_ssa/src/base.rs
View file

@ -609,7 +609,15 @@ pub fn collect_debugger_visualizers_transitive(
) -> BTreeSet<DebuggerVisualizerFile> {
tcx.debugger_visualizers(LOCAL_CRATE)
.iter()
.chain(tcx.crates(()).iter().flat_map(|&cnum| tcx.debugger_visualizers(cnum)))
.chain(
tcx.crates(())
.iter()
.filter(|&cnum| {
let used_crate_source = tcx.used_crate_source(*cnum);
used_crate_source.rlib.is_some() || used_crate_source.rmeta.is_some()
})
.flat_map(|&cnum| tcx.debugger_visualizers(cnum)),
)
.filter(|visualizer| visualizer.visualizer_type == visualizer_type)
.cloned()
.collect::<BTreeSet<_>>()

2
compiler/rustc_codegen_ssa/src/traits/debuginfo.rs
View file

@ -50,7 +50,7 @@ pub trait DebugInfoCodegenMethods<'tcx>: BackendTypes {
scope_metadata: Self::DIScope,
file: &SourceFile,
) -> Self::DIScope;
fn debuginfo_finalize(&mut self);
fn debuginfo_finalize(&self);
// FIXME(eddyb) find a common convention for all of the debuginfo-related
// names (choose between `dbg`, `debug`, `debuginfo`, `debug_info` etc.).

4
tests/codegen-llvm/gdb_debug_script_load.rs
View file

@ -9,8 +9,6 @@
#![feature(lang_items)]
#![no_std]
// CHECK: @llvm.used = {{.+}} @__rustc_debug_gdb_scripts_section
#[panic_handler]
fn panic_handler(_: &core::panic::PanicInfo) -> ! {
loop {}
@ -24,7 +22,7 @@ extern "C" fn rust_eh_personality() {
// Needs rustc to generate `main` as that's where the magic load is inserted.
// IOW, we cannot write this test with `#![no_main]`.
// CHECK-LABEL: @main
// CHECK: load volatile i8, {{.+}} @__rustc_debug_gdb_scripts_section
// CHECK: load volatile i8, {{.+}} @__rustc_debug_gdb_scripts_section__
#[lang = "start"]
fn lang_start<T: 'static>(

35
tests/run-make/symbols-all-mangled/rmake.rs
View file

@ -35,7 +35,13 @@ fn symbols_check_archive(path: &str) {
continue; // All compiler-builtins symbols must remain unmangled
}
if symbol_ok_everywhere(name) {
if name.contains("rust_eh_personality") {
continue; // Unfortunately LLVM doesn't allow us to mangle this symbol
}
if name.contains(".llvm.") {
// Starting in LLVM 21 we get various implementation-detail functions which
// contain .llvm. that are not a problem.
continue;
}
@ -65,7 +71,13 @@ fn symbols_check(path: &str) {
continue;
}
if symbol_ok_everywhere(name) {
if name.contains("rust_eh_personality") {
continue; // Unfortunately LLVM doesn't allow us to mangle this symbol
}
if name.contains(".llvm.") {
// Starting in LLVM 21 we get various implementation-detail functions which
// contain .llvm. that are not a problem.
continue;
}
@ -76,22 +88,3 @@ fn symbols_check(path: &str) {
fn strip_underscore_if_apple(symbol: &str) -> &str {
if cfg!(target_vendor = "apple") { symbol.strip_prefix("_").unwrap() } else { symbol }
}
fn symbol_ok_everywhere(name: &str) -> bool {
if name.contains("rust_eh_personality") {
return true; // Unfortunately LLVM doesn't allow us to mangle this symbol
}
if name.contains(".llvm.") {
// Starting in LLVM 21 we get various implementation-detail functions which
// contain .llvm. that are not a problem.
return true;
}
if name.starts_with("__rustc_debug_gdb_scripts_section") {
// These symbols are fine; they're made unique by the crate ID.
return true;
}
return false;
}