Auto merge of #108446 - Zoxc:named-allocs, r=oli-obk

Name LLVM anonymous constants by a hash of their contents

This makes the names stable between different versions of a crate unlike the `AllocId` naming, making LLVM IR comparisons with `llvm-diff` more practical.
This commit is contained in:
bors 2023-03-01 15:36:15 +00:00
commit 609496eecf
3 changed files with 11 additions and 5 deletions

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@ -10,6 +10,7 @@ use crate::value::Value;
use rustc_ast::Mutability;
use rustc_codegen_ssa::mir::place::PlaceRef;
use rustc_codegen_ssa::traits::*;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_hir::def_id::DefId;
use rustc_middle::bug;
use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc, Scalar};
@ -252,8 +253,13 @@ 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::set_value_name(value, format!("{:?}", alloc_id).as_bytes());
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::<u128>()
});
llvm::set_value_name(value, format!("alloc_{hash:032x}").as_bytes());
}
(value, AddressSpace::DATA)
}

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@ -9,11 +9,11 @@
// CHECK: @STATIC = {{.*}}, align 4
// This checks the constants from inline_enum_const
// CHECK: @alloc12 = {{.*}}, align 2
// CHECK: @alloc_76bfe2f13a3e3b01074971d122eac57e = {{.*}}, 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[0-9]+]] = {{.*}}, align 4
// CHECK: [[LOW_HIGH:@alloc_[a-f0-9]+]] = {{.*}}, align 4
#[derive(Copy, Clone)]
// repr(i16) is required for the {low,high}_align_const test

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@ -12,7 +12,7 @@ mod aux_mod;
include!("aux_mod.rs");
// Here we check that the expansion of the file!() macro is mapped.
// CHECK: @alloc2 = private unnamed_addr constant <{ [34 x i8] }> <{ [34 x i8] c"/the/src/remap_path_prefix/main.rs" }>
// CHECK: @alloc_92a59126a55aa3c0019b6c8a007fe001 = 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() {