Auto merge of #119458 - cjgillot:anonymous-alloc, r=compiler-errors

Do not hash allocations to name them. Computing the stable hash behind an `Allocation` can be quite slow. The given name does not provide a lot of benefit: a hash is not meaningfully easier to understand than an arbitrary index.
rust-lang · Feb 25, 2024 · bf96619 · bf96619
2 parents 2ae1bb6 + cb6e396
commit bf96619
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Showing 3 changed files with 5 additions and 14 deletions.
diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs
@@ -8,7 +8,6 @@ use crate::value::Value;
 
 use rustc_ast::Mutability;
 use rustc_codegen_ssa::traits::*;
-use rustc_data_structures::stable_hasher::{Hash128, HashStable, StableHasher};
 use rustc_hir::def_id::DefId;
 use rustc_middle::bug;
 use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc, Scalar};
@@ -255,14 +254,6 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                             Mutability::Mut => self.static_addr_of_mut(init, alloc.align, None),
                             _ => self.static_addr_of(init, alloc.align, None),
                         };
-                        if !self.sess().fewer_names() && llvm::get_value_name(value).is_empty() {
-                            let hash = self.tcx.with_stable_hashing_context(|mut hcx| {
-                                let mut hasher = StableHasher::new();
-                                alloc.hash_stable(&mut hcx, &mut hasher);
-                                hasher.finish::<Hash128>()
-                            });
-                            llvm::set_value_name(value, format!("alloc_{hash:032x}").as_bytes());
-                        }
                         (value, AddressSpace::DATA)
                     }
                     GlobalAlloc::Function(fn_instance) => (

diff --git a/tests/codegen/consts.rs b/tests/codegen/consts.rs
@@ -9,11 +9,11 @@
 // CHECK: @STATIC = {{.*}}, align 4
 
 // This checks the constants from inline_enum_const
-// CHECK: @alloc_af1f8e8e6f4b341431a1d405e652df2d = {{.*}}, align 2
+// CHECK: @0 = {{.*}}, align 2
 
 // This checks the constants from {low,high}_align_const, they share the same
 // constant, but the alignment differs, so the higher one should be used
-// CHECK: [[LOW_HIGH:@alloc_[a-f0-9]+]] = {{.*}}, align 4
+// CHECK: @1 = {{.*}}, align 4
 
 #[derive(Copy, Clone)]
 // repr(i16) is required for the {low,high}_align_const test
@@ -42,14 +42,14 @@ pub fn inline_enum_const() -> E<i8, i16> {
 #[no_mangle]
 pub fn low_align_const() -> E<i16, [i16; 3]> {
     // Check that low_align_const and high_align_const use the same constant
-    // CHECK: memcpy.{{.+}}(ptr align 2 %_0, ptr align 2 {{.*}}[[LOW_HIGH]]{{.*}}, i{{(32|64)}} 8, i1 false)
+    // CHECK: memcpy.{{.+}}(ptr align 2 %_0, ptr align 2 {{.*}}@1{{.*}}, i{{(32|64)}} 8, i1 false)
     *&E::A(0)
 }
 
 // CHECK-LABEL: @high_align_const
 #[no_mangle]
 pub fn high_align_const() -> E<i16, i32> {
     // Check that low_align_const and high_align_const use the same constant
-    // CHECK: memcpy.{{.+}}(ptr align 4 %_0, ptr align 4 {{.*}}[[LOW_HIGH]]{{.*}}, i{{(32|64)}} 8, i1 false)
+    // CHECK: memcpy.{{.+}}(ptr align 4 %_0, ptr align 4 {{.*}}@1{{.*}}, i{{(32|64)}} 8, i1 false)
     *&E::A(0)
 }
diff --git a/tests/codegen/remap_path_prefix/main.rs b/tests/codegen/remap_path_prefix/main.rs
@@ -12,7 +12,7 @@ mod aux_mod;
 include!("aux_mod.rs");
 
 // Here we check that the expansion of the file!() macro is mapped.
-// CHECK: @alloc_5761061597a97f66e13ef2ff92712c4b = private unnamed_addr constant <{ [34 x i8] }> <{ [34 x i8] c"/the/src/remap_path_prefix/main.rs" }>
+// CHECK: @0 = private unnamed_addr constant <{ [34 x i8] }> <{ [34 x i8] c"/the/src/remap_path_prefix/main.rs" }>
 pub static FILE_PATH: &'static str = file!();
 
 fn main() {