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 {
@@ -90,6 +90,7 @@ fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span
 
     let attrs = thin_vec![cx.attr_word(sym::rustc_std_internal_symbol, span)];
 
-    let item = cx.item(span, Ident::from_str_and_span("__rg_oom", span), attrs, kind);
+    let item =
+        cx.item(span, Ident::from_str_and_span("__rust_alloc_error_handler", span), attrs, kind);
     cx.stmt_item(sig_span, item)
 }

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;
 
@@ -12,36 +10,14 @@ 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(
-            module,
-            tcx.alloc_error_handler_kind(()).unwrap(),
-            tcx.sess.opts.unstable_opts.oom,
-        );
+        codegen_inner(module, tcx.sess.opts.unstable_opts.oom);
         true
     } else {
         false
     }
 }
 
-fn codegen_inner(
-    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,
-        "__rust_alloc_error_handler",
-        &alloc_error_handler_name(alloc_error_handler_kind),
-    );
-
+fn codegen_inner(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);

compiler/rustc_codegen_gcc/src/allocator.rs

@@ -1,42 +1,18 @@
-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 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,
-        "__rust_alloc_error_handler",
-        alloc_error_handler_name(alloc_error_handler_kind),
-        &[usize, usize],
-        None,
-    );
-
     let name = OomStrategy::SYMBOL.to_string();
     let global = context.new_global(None, GlobalKind::Exported, i8, name);
     #[cfg(feature = "master")]
@@ -56,71 +32,3 @@ 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::{
@@ -286,12 +285,7 @@ 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(),
@@ -300,7 +294,7 @@ 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

@@ -1,45 +1,16 @@
-use libc::c_uint;
-use rustc_ast::expand::allocator::{
-    AllocatorKind, NO_ALLOC_SHIM_IS_UNSTABLE, alloc_error_handler_name,
-};
-use rustc_middle::bug;
+use rustc_ast::expand::allocator::NO_ALLOC_SHIM_IS_UNSTABLE;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{DebugInfo, OomStrategy};
 
 use crate::common::AsCCharPtr;
-use crate::llvm::{self, Context, False, Module, True, Type};
-use crate::{ModuleLlvm, attributes, debuginfo};
+use crate::llvm::{self, False};
+use crate::{ModuleLlvm, debuginfo};
 
-pub(crate) unsafe fn codegen(
-    tcx: TyCtxt<'_>,
-    module_llvm: &mut ModuleLlvm,
-    module_name: &str,
-    alloc_error_handler_kind: AllocatorKind,
-) {
+pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, module_llvm: &mut ModuleLlvm, module_name: &str) {
     let llcx = &*module_llvm.llcx;
     let llmod = module_llvm.llmod();
-    let usize = unsafe {
-        match tcx.sess.target.pointer_width {
-            16 => llvm::LLVMInt16TypeInContext(llcx),
-            32 => llvm::LLVMInt32TypeInContext(llcx),
-            64 => llvm::LLVMInt64TypeInContext(llcx),
-            tws => bug!("Unsupported target word size for int: {}", tws),
-        }
-    };
     let i8 = unsafe { llvm::LLVMInt8TypeInContext(llcx) };
 
-    // rust alloc error handler
-    create_wrapper_function(
-        tcx,
-        llcx,
-        llmod,
-        "__rust_alloc_error_handler",
-        alloc_error_handler_name(alloc_error_handler_kind),
-        &[usize, usize], // size, align
-        None,
-        true,
-    );
-
     unsafe {
         // __rust_alloc_error_handler_should_panic
         let name = OomStrategy::SYMBOL;
@@ -62,80 +33,3 @@ pub(crate) unsafe fn codegen(
         dbg_cx.finalize(tcx.sess);
     }
 }
-
-fn create_wrapper_function(
-    tcx: TyCtxt<'_>,
-    llcx: &Context,
-    llmod: &Module,
-    from_name: &str,
-    to_name: &str,
-    args: &[&Type],
-    output: Option<&Type>,
-    no_return: bool,
-) {
-    unsafe {
-        let ty = llvm::LLVMFunctionType(
-            output.unwrap_or_else(|| llvm::LLVMVoidTypeInContext(llcx)),
-            args.as_ptr(),
-            args.len() as c_uint,
-            False,
-        );
-        let llfn = llvm::LLVMRustGetOrInsertFunction(
-            llmod,
-            from_name.as_c_char_ptr(),
-            from_name.len(),
-            ty,
-        );
-        let no_return = if no_return {
-            // -> ! DIFlagNoReturn
-            let no_return = llvm::AttributeKind::NoReturn.create_attr(llcx);
-            attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[no_return]);
-            Some(no_return)
-        } else {
-            None
-        };
-
-        llvm::set_visibility(llfn, llvm::Visibility::from_generic(tcx.sess.default_visibility()));
-
-        if tcx.sess.must_emit_unwind_tables() {
-            let uwtable =
-                attributes::uwtable_attr(llcx, tcx.sess.opts.unstable_opts.use_sync_unwind);
-            attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
-        }
-
-        let callee =
-            llvm::LLVMRustGetOrInsertFunction(llmod, to_name.as_c_char_ptr(), to_name.len(), 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 = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, c"entry".as_ptr());
-
-        let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
-        llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);
-        let args = args
-            .iter()
-            .enumerate()
-            .map(|(i, _)| llvm::LLVMGetParam(llfn, i as c_uint))
-            .collect::<Vec<_>>();
-        let ret = llvm::LLVMBuildCallWithOperandBundles(
-            llbuilder,
-            ty,
-            callee,
-            args.as_ptr(),
-            args.len() as c_uint,
-            [].as_ptr(),
-            0 as c_uint,
-            c"".as_ptr(),
-        );
-        llvm::LLVMSetTailCall(ret, True);
-        if output.is_some() {
-            llvm::LLVMBuildRet(llbuilder, ret);
-        } else {
-            llvm::LLVMBuildRetVoid(llbuilder);
-        }
-        llvm::LLVMDisposeBuilder(llbuilder);
-    }
-}

compiler/rustc_codegen_llvm/src/lib.rs

@@ -30,7 +30,6 @@ use back::owned_target_machine::OwnedTargetMachine;
 use back::write::{create_informational_target_machine, create_target_machine};
 use errors::{AutoDiffWithoutLTO, ParseTargetMachineConfig};
 pub use llvm_util::target_features_cfg;
-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::{
@@ -113,15 +112,10 @@ 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 mut module_llvm = ModuleLlvm::new_metadata(tcx, module_name);
         unsafe {
-            allocator::codegen(tcx, &mut module_llvm, module_name, alloc_error_handler_kind);
+            allocator::codegen(tcx, &mut module_llvm, module_name);
         }
         module_llvm
     }