From 56074b5231ceef266a1097ea355f62c951e1b468 Mon Sep 17 00:00:00 2001 From: Amanieu d'Antras Date: Fri, 14 Oct 2022 02:24:58 +0100 Subject: Rewrite implementation of `#[alloc_error_handler]` The new implementation doesn't use weak lang items and instead changes `#[alloc_error_handler]` to an attribute macro just like `#[global_allocator]`. The attribute will generate the `__rg_oom` function which is called by the compiler-generated `__rust_alloc_error_handler`. If no `__rg_oom` function is defined in any crate then the compiler shim will call `__rdl_oom` in the alloc crate which will simply panic. This also fixes link errors with `-C link-dead-code` with `default_alloc_error_handler`: `__rg_oom` was previously defined in the alloc crate and would attempt to reference the `oom` lang item, even if it didn't exist. This worked as long as `__rg_oom` was excluded from linking since it was not called. This is a prerequisite for the stabilization of `default_alloc_error_handler` (#102318). --- compiler/rustc_codegen_ssa/src/back/symbol_export.rs | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'compiler/rustc_codegen_ssa/src/back') diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs index c2ecc41601c..752f6b1ef40 100644 --- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs +++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs @@ -193,8 +193,11 @@ fn exported_symbols_provider_local<'tcx>( } if tcx.allocator_kind(()).is_some() { - for method in ALLOCATOR_METHODS { - let symbol_name = format!("__rust_{}", method.name); + for symbol_name in ALLOCATOR_METHODS + .iter() + .map(|method| format!("__rust_{}", method.name)) + .chain(["__rust_alloc_error_handler".to_string(), OomStrategy::SYMBOL.to_string()]) + { let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name)); symbols.push(( -- cgit 1.4.1-3-g733a5