Auto merge of #104054 - RalfJung:byte-provenance, r=oli-obk

interpret: support for per-byte provenance

Also factors the provenance map into its own module.

The third commit does the same for the init mask. I can move it in a separate PR if you prefer.

Fixes rust-lang/miri#2181

r? `@oli-obk`

src/consts.rs

@@ -297,12 +297,12 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
 
 pub fn const_alloc_to_gcc<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, alloc: ConstAllocation<'tcx>) -> RValue<'gcc> {
     let alloc = alloc.inner();
-    let mut llvals = Vec::with_capacity(alloc.provenance().len() + 1);
+    let mut llvals = Vec::with_capacity(alloc.provenance().ptrs().len() + 1);
     let dl = cx.data_layout();
     let pointer_size = dl.pointer_size.bytes() as usize;
 
     let mut next_offset = 0;
-    for &(offset, alloc_id) in alloc.provenance().iter() {
+    for &(offset, alloc_id) in alloc.provenance().ptrs().iter() {
         let offset = offset.bytes();
         assert_eq!(offset as usize as u64, offset);
         let offset = offset as usize;