Auto merge of #142366 - bjorn3:aliases, r=<try>

[WIP] Use weak aliases for the allocator shim

try-job: x86_64-msvc-1
try-job: x86_64-msvc-2

Author: rust-bors[bot]

compiler/rustc_codegen_cranelift/src/driver/aot.rs

@@ -563,6 +563,7 @@ fn codegen_cgu_content(
                 );
                 codegened_functions.push(codegened_function);
             }
+            MonoItem::WeakAlias(_, _) => todo!(),
             MonoItem::Static(def_id) => {
                 let data_id = crate::constant::codegen_static(tcx, module, def_id);
                 if let Some(debug_context) = &mut cx.debug_context {

compiler/rustc_codegen_cranelift/src/driver/mod.rs

@@ -49,7 +49,7 @@ fn predefine_mono_items<'tcx>(
                         )
                         .unwrap();
                 }
-                MonoItem::Static(_) | MonoItem::GlobalAsm(_) => {}
+                MonoItem::WeakAlias(_, _) | MonoItem::Static(_) | MonoItem::GlobalAsm(_) => {}
             }
         }
     });

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -1,7 +1,6 @@
 use libc::c_uint;
 use rustc_ast::expand::allocator::{
-    ALLOCATOR_METHODS, AllocatorKind, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE,
-    alloc_error_handler_name, default_fn_name, global_fn_name,
+    AllocatorKind, NO_ALLOC_SHIM_IS_UNSTABLE, alloc_error_handler_name,
 };
 use rustc_codegen_ssa::traits::BaseTypeCodegenMethods as _;
 use rustc_middle::bug;
@@ -18,7 +17,6 @@ pub(crate) unsafe fn codegen(
     tcx: TyCtxt<'_>,
     cx: SimpleCx<'_>,
     module_name: &str,
-    kind: AllocatorKind,
     alloc_error_handler_kind: AllocatorKind,
 ) {
     let usize = match tcx.sess.target.pointer_width {
@@ -28,38 +26,6 @@ pub(crate) unsafe fn codegen(
         tws => bug!("Unsupported target word size for int: {}", tws),
     };
     let i8 = cx.type_i8();
-    let i8p = cx.type_ptr();
-
-    if kind == AllocatorKind::Default {
-        for method in ALLOCATOR_METHODS {
-            let mut args = Vec::with_capacity(method.inputs.len());
-            for input in method.inputs.iter() {
-                match input.ty {
-                    AllocatorTy::Layout => {
-                        args.push(usize); // size
-                        args.push(usize); // align
-                    }
-                    AllocatorTy::Ptr => args.push(i8p),
-                    AllocatorTy::Usize => args.push(usize),
-
-                    AllocatorTy::ResultPtr | AllocatorTy::Unit => panic!("invalid allocator arg"),
-                }
-            }
-            let output = match method.output {
-                AllocatorTy::ResultPtr => Some(i8p),
-                AllocatorTy::Unit => None,
-
-                AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
-                    panic!("invalid allocator output")
-                }
-            };
-
-            let from_name = mangle_internal_symbol(tcx, &global_fn_name(method.name));
-            let to_name = mangle_internal_symbol(tcx, &default_fn_name(method.name));
-
-            create_wrapper_function(tcx, &cx, &from_name, &to_name, &args, output, false);
-        }
-    }
 
     // rust alloc error handler
     create_wrapper_function(

compiler/rustc_codegen_llvm/src/base.rs

@@ -118,8 +118,11 @@ pub(crate) fn compile_codegen_unit(
             if !cx.used_statics.is_empty() {
                 cx.create_used_variable_impl(c"llvm.used", &cx.used_statics);
             }
-            if !cx.compiler_used_statics.is_empty() {
-                cx.create_used_variable_impl(c"llvm.compiler.used", &cx.compiler_used_statics);
+            if !cx.compiler_used_statics.borrow().is_empty() {
+                cx.create_used_variable_impl(
+                    c"llvm.compiler.used",
+                    &*cx.compiler_used_statics.borrow(),
+                );
             }
 
             // Run replace-all-uses-with for statics that need it. This must

compiler/rustc_codegen_llvm/src/builder.rs

@@ -5,8 +5,7 @@ use std::{iter, ptr};
 pub(crate) mod autodiff;
 
 use libc::{c_char, c_uint, size_t};
-use rustc_abi as abi;
-use rustc_abi::{Align, Size, WrappingRange};
+use rustc_abi::{self as abi, Align, Size, WrappingRange};
 use rustc_codegen_ssa::MemFlags;
 use rustc_codegen_ssa::common::{IntPredicate, RealPredicate, SynchronizationScope, TypeKind};
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};

compiler/rustc_codegen_llvm/src/consts.rs

@@ -549,8 +549,8 @@ impl<'ll> CodegenCx<'ll, '_> {
 
     /// Add a global value to a list to be stored in the `llvm.compiler.used` variable,
     /// an array of ptr.
-    pub(crate) fn add_compiler_used_global(&mut self, global: &'ll Value) {
-        self.compiler_used_statics.push(global);
+    pub(crate) fn add_compiler_used_global(&self, global: &'ll Value) {
+        self.compiler_used_statics.borrow_mut().push(global);
     }
 }
 

compiler/rustc_codegen_llvm/src/context.rs

@@ -121,7 +121,7 @@ pub(crate) struct FullCx<'ll, 'tcx> {
 
     /// Statics that will be placed in the llvm.compiler.used variable
     /// See <https://llvm.org/docs/LangRef.html#the-llvm-compiler-used-global-variable> for details
-    pub compiler_used_statics: Vec<&'ll Value>,
+    pub compiler_used_statics: RefCell<Vec<&'ll Value>>,
 
     /// Mapping of non-scalar types to llvm types.
     pub type_lowering: RefCell<FxHashMap<(Ty<'tcx>, Option<VariantIdx>), &'ll Type>>,
@@ -614,7 +614,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
                 const_globals: Default::default(),
                 statics_to_rauw: RefCell::new(Vec::new()),
                 used_statics: Vec::new(),
-                compiler_used_statics: Vec::new(),
+                compiler_used_statics: RefCell::new(Vec::new()),
                 type_lowering: Default::default(),
                 scalar_lltypes: Default::default(),
                 coverage_cx,

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/unused.rs

@@ -110,7 +110,9 @@ fn prepare_usage_sets<'tcx>(tcx: TyCtxt<'tcx>) -> UsageSets<'tcx> {
         .flat_map(|cgu| cgu.items().keys())
         .filter_map(|item| match item {
             mir::mono::MonoItem::Fn(instance) => Some(instance),
-            mir::mono::MonoItem::Static(_) | mir::mono::MonoItem::GlobalAsm(_) => None,
+            mir::mono::MonoItem::WeakAlias(_, _)
+            | mir::mono::MonoItem::Static(_)
+            | mir::mono::MonoItem::GlobalAsm(_) => None,
         })
         // We only need one arbitrary instance per definition.
         .filter(move |instance| def_ids_seen.insert(instance.def_id()))

compiler/rustc_codegen_llvm/src/lib.rs

@@ -108,14 +108,14 @@ impl ExtraBackendMethods for LlvmCodegenBackend {
         &self,
         tcx: TyCtxt<'tcx>,
         module_name: &str,
-        kind: AllocatorKind,
+        _kind: AllocatorKind,
         alloc_error_handler_kind: AllocatorKind,
     ) -> 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, kind, alloc_error_handler_kind);
+            allocator::codegen(tcx, cx, module_name, alloc_error_handler_kind);
         }
         module_llvm
     }

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2083,6 +2083,8 @@ unsafe extern "C" {
         ValueLen: size_t,
     );
 
+    pub(crate) fn LLVMRustAddLinkerOptions(M: &Module, Value: *const c_char, ValueLen: size_t);
+
     pub(crate) fn LLVMRustDIBuilderCreateCompileUnit<'a>(
         Builder: &DIBuilder<'a>,
         Lang: c_uint,
@@ -2662,4 +2664,12 @@ unsafe extern "C" {
 
     pub(crate) fn LLVMRustSetNoSanitizeAddress(Global: &Value);
     pub(crate) fn LLVMRustSetNoSanitizeHWAddress(Global: &Value);
+
+    pub(crate) fn LLVMAddAlias2<'ll>(
+        M: &'ll Module,
+        ValueTy: &Type,
+        AddressSpace: c_uint,
+        Aliasee: &Value,
+        Name: *const c_char,
+    ) -> &'ll Value;
 }