Use weak linkage for the alloc error handler too

Author: bjorn3

compiler/rustc_ast/src/expand/allocator.rs

@@ -11,13 +11,6 @@ pub fn global_fn_name(base: Symbol) -> String {
     format!("__rust_{base}")
 }
 
-pub fn alloc_error_handler_name(alloc_error_handler_kind: AllocatorKind) -> &'static str {
-    match alloc_error_handler_kind {
-        AllocatorKind::Global => "__rg_oom",
-        AllocatorKind::Default => "__rdl_oom",
-    }
-}
-
 pub const NO_ALLOC_SHIM_IS_UNSTABLE: &str = "__rust_no_alloc_shim_is_unstable";
 
 pub enum AllocatorTy {

compiler/rustc_builtin_macros/src/alloc_error_handler.rs

@@ -56,7 +56,7 @@ pub(crate) fn expand(
 }
 
 // #[rustc_std_internal_symbol]
-// unsafe fn __rg_oom(size: usize, align: usize) -> ! {
+// unsafe fn __rust_alloc_error_handler(size: usize, align: usize) -> ! {
 //     handler(core::alloc::Layout::from_size_align_unchecked(size, align))
 // }
 fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span) -> Stmt {
@@ -85,7 +85,7 @@ fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span
     let kind = ItemKind::Fn(Box::new(Fn {
         defaultness: ast::Defaultness::Final,
         sig,
-        ident: Ident::from_str_and_span("__rg_oom", span),
+        ident: Ident::from_str_and_span("__rust_alloc_error_handler", span),
         generics: Generics::default(),
         contract: None,
         body,

compiler/rustc_codegen_cranelift/src/allocator.rs

@@ -1,9 +1,7 @@
 //! Allocator shim
 // Adapted from rustc
 
-use rustc_ast::expand::allocator::{
-    AllocatorKind, NO_ALLOC_SHIM_IS_UNSTABLE, alloc_error_handler_name,
-};
+use rustc_ast::expand::allocator::NO_ALLOC_SHIM_IS_UNSTABLE;
 use rustc_codegen_ssa::base::needs_allocator_shim;
 use rustc_session::config::OomStrategy;
 use rustc_symbol_mangling::mangle_internal_symbol;
@@ -13,46 +11,15 @@ use crate::prelude::*;
 /// Returns whether an allocator shim was created
 pub(crate) fn codegen(tcx: TyCtxt<'_>, module: &mut dyn Module) -> bool {
     if needs_allocator_shim(tcx) {
-        codegen_inner(
-            tcx,
-            module,
-            tcx.alloc_error_handler_kind(()).unwrap(),
-            tcx.sess.opts.unstable_opts.oom,
-        );
+        codegen_inner(tcx, module, tcx.sess.opts.unstable_opts.oom);
         true
     } else {
         false
     }
 }
 
-fn codegen_inner(
-    tcx: TyCtxt<'_>,
-    module: &mut dyn Module,
-    alloc_error_handler_kind: AllocatorKind,
-    oom_strategy: OomStrategy,
-) {
-    let usize_ty = module.target_config().pointer_type();
-
-    let sig = Signature {
-        call_conv: module.target_config().default_call_conv,
-        params: vec![AbiParam::new(usize_ty), AbiParam::new(usize_ty)],
-        returns: vec![],
-    };
-    crate::common::create_wrapper_function(
-        module,
-        sig,
-        &mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
-        &mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind)),
-    );
-
-    let data_id = module
-        .declare_data(
-            &mangle_internal_symbol(tcx, OomStrategy::SYMBOL),
-            Linkage::Export,
-            false,
-            false,
-        )
-        .unwrap();
+fn codegen_inner(tcx: TyCtxt<'_>, module: &mut dyn Module, oom_strategy: OomStrategy) {
+    let data_id = module.declare_data(OomStrategy::SYMBOL, Linkage::Export, false, false).unwrap();
     let mut data = DataDescription::new();
     data.set_align(1);
     let val = oom_strategy.should_panic();

compiler/rustc_codegen_gcc/src/allocator.rs

@@ -1,10 +1,7 @@
-use gccjit::{Context, FunctionType, GlobalKind, ToRValue, Type};
+use gccjit::GlobalKind;
 #[cfg(feature = "master")]
-use gccjit::{FnAttribute, VarAttribute};
-use rustc_ast::expand::allocator::{
-    AllocatorKind, NO_ALLOC_SHIM_IS_UNSTABLE, alloc_error_handler_name,
-};
-use rustc_middle::bug;
+use gccjit::VarAttribute;
+use rustc_ast::expand::allocator::NO_ALLOC_SHIM_IS_UNSTABLE;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::OomStrategy;
 use rustc_symbol_mangling::mangle_internal_symbol;
@@ -13,31 +10,10 @@ use crate::GccContext;
 #[cfg(feature = "master")]
 use crate::base::symbol_visibility_to_gcc;
 
-pub(crate) unsafe fn codegen(
-    tcx: TyCtxt<'_>,
-    mods: &mut GccContext,
-    _module_name: &str,
-    alloc_error_handler_kind: AllocatorKind,
-) {
+pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut GccContext, _module_name: &str) {
     let context = &mods.context;
-    let usize = match tcx.sess.target.pointer_width {
-        16 => context.new_type::<u16>(),
-        32 => context.new_type::<u32>(),
-        64 => context.new_type::<u64>(),
-        tws => bug!("Unsupported target word size for int: {}", tws),
-    };
     let i8 = context.new_type::<i8>();
 
-    // FIXME(bjorn3): Add noreturn attribute
-    create_wrapper_function(
-        tcx,
-        context,
-        &mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
-        &mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind)),
-        &[usize, usize],
-        None,
-    );
-
     let name = mangle_internal_symbol(tcx, OomStrategy::SYMBOL);
     let global = context.new_global(None, GlobalKind::Exported, i8, name);
     #[cfg(feature = "master")]
@@ -57,71 +33,3 @@ pub(crate) unsafe fn codegen(
     let value = context.new_rvalue_from_int(i8, 0);
     global.global_set_initializer_rvalue(value);
 }
-
-fn create_wrapper_function(
-    tcx: TyCtxt<'_>,
-    context: &Context<'_>,
-    from_name: &str,
-    to_name: &str,
-    types: &[Type<'_>],
-    output: Option<Type<'_>>,
-) {
-    let void = context.new_type::<()>();
-
-    let args: Vec<_> = types
-        .iter()
-        .enumerate()
-        .map(|(index, typ)| context.new_parameter(None, *typ, format!("param{}", index)))
-        .collect();
-    let func = context.new_function(
-        None,
-        FunctionType::Exported,
-        output.unwrap_or(void),
-        &args,
-        from_name,
-        false,
-    );
-
-    #[cfg(feature = "master")]
-    func.add_attribute(FnAttribute::Visibility(symbol_visibility_to_gcc(
-        tcx.sess.default_visibility(),
-    )));
-
-    if tcx.sess.must_emit_unwind_tables() {
-        // TODO(antoyo): emit unwind tables.
-    }
-
-    let args: Vec<_> = types
-        .iter()
-        .enumerate()
-        .map(|(index, typ)| context.new_parameter(None, *typ, format!("param{}", index)))
-        .collect();
-    let callee = context.new_function(
-        None,
-        FunctionType::Extern,
-        output.unwrap_or(void),
-        &args,
-        to_name,
-        false,
-    );
-    #[cfg(feature = "master")]
-    callee.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));
-
-    let block = func.new_block("entry");
-
-    let args = args
-        .iter()
-        .enumerate()
-        .map(|(i, _)| func.get_param(i as i32).to_rvalue())
-        .collect::<Vec<_>>();
-    let ret = context.new_call(None, callee, &args);
-    //llvm::LLVMSetTailCall(ret, True);
-    if output.is_some() {
-        block.end_with_return(None, ret);
-    } else {
-        block.end_with_void_return(None);
-    }
-
-    // TODO(@Commeownist): Check if we need to emit some extra debugging info in certain circumstances
-    // as described in https://github.com/rust-lang/rust/commit/77a96ed5646f7c3ee8897693decc4626fe380643
-}

compiler/rustc_codegen_gcc/src/lib.rs

@@ -93,7 +93,6 @@ use back::lto::{ThinBuffer, ThinData};
 use gccjit::{CType, Context, OptimizationLevel};
 #[cfg(feature = "master")]
 use gccjit::{TargetInfo, Version};
-use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_ast::expand::autodiff_attrs::AutoDiffItem;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
 use rustc_codegen_ssa::back::write::{
@@ -274,12 +273,7 @@ fn new_context<'gcc, 'tcx>(tcx: TyCtxt<'tcx>) -> Context<'gcc> {
 }
 
 impl ExtraBackendMethods for GccCodegenBackend {
-    fn codegen_allocator(
-        &self,
-        tcx: TyCtxt<'_>,
-        module_name: &str,
-        alloc_error_handler_kind: AllocatorKind,
-    ) -> Self::Module {
+    fn codegen_allocator(&self, tcx: TyCtxt<'_>, module_name: &str) -> Self::Module {
         let mut mods = GccContext {
             context: Arc::new(SyncContext::new(new_context(tcx))),
             relocation_model: tcx.sess.relocation_model(),
@@ -288,7 +282,7 @@ impl ExtraBackendMethods for GccCodegenBackend {
         };
 
         unsafe {
-            allocator::codegen(tcx, &mut mods, module_name, alloc_error_handler_kind);
+            allocator::codegen(tcx, &mut mods, module_name);
         }
         mods
     }

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -1,43 +1,15 @@
-use libc::c_uint;
-use rustc_ast::expand::allocator::{
-    AllocatorKind, NO_ALLOC_SHIM_IS_UNSTABLE, alloc_error_handler_name,
-};
+use rustc_ast::expand::allocator::NO_ALLOC_SHIM_IS_UNSTABLE;
 use rustc_codegen_ssa::traits::BaseTypeCodegenMethods as _;
-use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{DebugInfo, OomStrategy};
 use rustc_symbol_mangling::mangle_internal_symbol;
 
-use crate::builder::SBuilder;
-use crate::declare::declare_simple_fn;
-use crate::llvm::{self, False, True, Type};
-use crate::{SimpleCx, attributes, debuginfo};
+use crate::llvm::{self, False};
+use crate::{SimpleCx, debuginfo};
 
-pub(crate) unsafe fn codegen(
-    tcx: TyCtxt<'_>,
-    cx: SimpleCx<'_>,
-    module_name: &str,
-    alloc_error_handler_kind: AllocatorKind,
-) {
-    let usize = match tcx.sess.target.pointer_width {
-        16 => cx.type_i16(),
-        32 => cx.type_i32(),
-        64 => cx.type_i64(),
-        tws => bug!("Unsupported target word size for int: {}", tws),
-    };
+pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, cx: SimpleCx<'_>, module_name: &str) {
     let i8 = cx.type_i8();
 
-    // rust alloc error handler
-    create_wrapper_function(
-        tcx,
-        &cx,
-        &mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
-        &mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind)),
-        &[usize, usize], // size, align
-        None,
-        true,
-    );
-
     unsafe {
         // __rust_alloc_error_handler_should_panic
         let name = mangle_internal_symbol(tcx, OomStrategy::SYMBOL);
@@ -60,67 +32,3 @@ pub(crate) unsafe fn codegen(
         dbg_cx.finalize(tcx.sess);
     }
 }
-
-fn create_wrapper_function(
-    tcx: TyCtxt<'_>,
-    cx: &SimpleCx<'_>,
-    from_name: &str,
-    to_name: &str,
-    args: &[&Type],
-    output: Option<&Type>,
-    no_return: bool,
-) {
-    let ty = cx.type_func(args, output.unwrap_or_else(|| cx.type_void()));
-    let llfn = declare_simple_fn(
-        &cx,
-        from_name,
-        llvm::CallConv::CCallConv,
-        llvm::UnnamedAddr::Global,
-        llvm::Visibility::from_generic(tcx.sess.default_visibility()),
-        ty,
-    );
-    let no_return = if no_return {
-        // -> ! DIFlagNoReturn
-        let no_return = llvm::AttributeKind::NoReturn.create_attr(cx.llcx);
-        attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[no_return]);
-        Some(no_return)
-    } else {
-        None
-    };
-
-    if tcx.sess.must_emit_unwind_tables() {
-        let uwtable =
-            attributes::uwtable_attr(cx.llcx, tcx.sess.opts.unstable_opts.use_sync_unwind);
-        attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
-    }
-
-    let callee = declare_simple_fn(
-        &cx,
-        to_name,
-        llvm::CallConv::CCallConv,
-        llvm::UnnamedAddr::Global,
-        llvm::Visibility::Hidden,
-        ty,
-    );
-    if let Some(no_return) = no_return {
-        // -> ! DIFlagNoReturn
-        attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]);
-    }
-    llvm::set_visibility(callee, llvm::Visibility::Hidden);
-
-    let llbb = unsafe { llvm::LLVMAppendBasicBlockInContext(cx.llcx, llfn, c"entry".as_ptr()) };
-
-    let mut bx = SBuilder::build(&cx, llbb);
-    let args = args
-        .iter()
-        .enumerate()
-        .map(|(i, _)| llvm::get_param(llfn, i as c_uint))
-        .collect::<Vec<_>>();
-    let ret = bx.call(ty, callee, &args, None);
-    llvm::LLVMSetTailCall(ret, True);
-    if output.is_some() {
-        bx.ret(ret);
-    } else {
-        bx.ret_void()
-    }
-}

compiler/rustc_codegen_llvm/src/lib.rs

@@ -28,7 +28,6 @@ use back::write::{create_informational_target_machine, create_target_machine};
 use context::SimpleCx;
 use errors::{AutoDiffWithoutLTO, ParseTargetMachineConfig};
 use llvm_util::target_config;
-use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_ast::expand::autodiff_attrs::AutoDiffItem;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
 use rustc_codegen_ssa::back::write::{
@@ -104,17 +103,12 @@ impl Drop for TimeTraceProfiler {
 }
 
 impl ExtraBackendMethods for LlvmCodegenBackend {
-    fn codegen_allocator<'tcx>(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        module_name: &str,
-        alloc_error_handler_kind: AllocatorKind,
-    ) -> ModuleLlvm {
+    fn codegen_allocator<'tcx>(&self, tcx: TyCtxt<'tcx>, module_name: &str) -> ModuleLlvm {
         let module_llvm = ModuleLlvm::new_metadata(tcx, module_name);
         let cx =
             SimpleCx::new(module_llvm.llmod(), &module_llvm.llcx, tcx.data_layout.pointer_size);
         unsafe {
-            allocator::codegen(tcx, cx, module_name, alloc_error_handler_kind);
+            allocator::codegen(tcx, cx, module_name);
         }
         module_llvm
     }

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1180,7 +1180,6 @@ unsafe extern "C" {
     pub(crate) fn LLVMSetThreadLocalMode(GlobalVar: &Value, Mode: ThreadLocalMode);
     pub(crate) fn LLVMIsGlobalConstant(GlobalVar: &Value) -> Bool;
     pub(crate) fn LLVMSetGlobalConstant(GlobalVar: &Value, IsConstant: Bool);
-    pub(crate) safe fn LLVMSetTailCall(CallInst: &Value, IsTailCall: Bool);
 
     // Operations on attributes
     pub(crate) fn LLVMCreateStringAttribute(