Auto merge of #115865 - RalfJung:mir-mod, r=oli-obk

move things out of mir/mod.rs

This moves a bunch of things out of `mir/mod.rs`:
- all const-related stuff to a new file consts.rs
- all statement/place/operand-related stuff to a new file statement.rs
- all pretty-printing related stuff to pretty.rs

`mod.rs` started out with 3100 lines and ends up with 1600. :)

Also there was some pretty-printing stuff in terminator.rs, that also got moved to pretty.rs, and I reordered things in pretty.rs so that it can be grouped by functionality.

Only the commit "use pretty_print_const_value from MIR constant 'extra' printing" has any behavior changes; it resolves the issue of having a fancy and a very crude pretty-printer for `ConstValue`.

r? `@oli-obk`

Author: bors

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -2,7 +2,8 @@
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
-use rustc_middle::mir::interpret::{read_target_uint, AllocId, ConstValue, GlobalAlloc, Scalar};
+use rustc_middle::mir::interpret::{read_target_uint, AllocId, GlobalAlloc, Scalar};
+use rustc_middle::mir::ConstValue;
 
 use cranelift_module::*;
 

compiler/rustc_codegen_ssa/src/common.rs

@@ -1,7 +1,7 @@
 #![allow(non_camel_case_types)]
 
 use rustc_hir::LangItem;
-use rustc_middle::mir::interpret::ConstValue;
+use rustc_middle::mir;
 use rustc_middle::ty::{self, layout::TyAndLayout, Ty, TyCtxt};
 use rustc_span::Span;
 
@@ -194,10 +194,10 @@ pub fn shift_mask_val<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 pub fn asm_const_to_str<'tcx>(
     tcx: TyCtxt<'tcx>,
     sp: Span,
-    const_value: ConstValue<'tcx>,
+    const_value: mir::ConstValue<'tcx>,
     ty_and_layout: TyAndLayout<'tcx>,
 ) -> String {
-    let ConstValue::Scalar(scalar) = const_value else {
+    let mir::ConstValue::Scalar(scalar) = const_value else {
         span_bug!(sp, "expected Scalar for promoted asm const, but got {:#?}", const_value)
     };
     let value = scalar.assert_bits(ty_and_layout.size);