…optimization

MC/DC's reliance on the existing branch coverage types is making it much harder
to improve branch coverage.

This clears the way for larger changes to how branches are handled by the
coverage instrumentor, in order to support branch coverage for more language
constructs.

checked_ilog: improve performance

Addresses rust-lang#115874.

(This PR replicates the original rust-lang#115875, which I accidentally closed by deleting my forked repository...)

…-obk

[cleanup] [llvm backend] Prevent creating the same `Instance::mono` multiple times

Just a little thing I came across while going through the code.

r? ```@oli-obk```

…, r=oli-obk

Stop taking `ParamTy`/`ParamConst`/`EarlyParamRegion`/`AliasTy` by ref

It's unnecessary and is annoying when we have it by value.

coverage: Prepare for improved branch coverage

When trying to rebase my new branch coverage work (including rust-lang#124154) on top of the introduction of MC/DC coverage (rust-lang#123409), I found it a lot harder than anticipated. With the benefit of hindsight, the branch coverage code and MC/DC code have become more interdependent than I'm happy with.

This PR therefore disentangles them a bit, so that it will be easier for both areas of code to evolve independently without interference.

---

This PR also includes a few extra branch coverage tests that I had sitting around from my current branch coverage work. They mostly just demonstrate that certain language constructs listed in rust-lang#124118 currently don't have branch coverage support.

``@rustbot`` label +A-code-coverage

…e, r=dtolnay

Stabilize generic `NonZero`.

Tracking issue: rust-lang#120257

r? `@dtolnay`

…read-ice, r=oli-obk

Improve ICE message for forbidden dep-graph reads.

The new message mentions the main context that the ICE might occur in and it mentions the query/dep-node that is being read.

cc rust-lang#123781, where this would have been helpful.

Update books

## rust-lang/book

41 commits in 3131aa4642c627a24f523c82566b94a7d920f68c..d207d894cc5e1d496ab99beeacd1a420e5d4d238
2024-04-19 19:48:19 UTC to 2024-04-08 19:34:07 UTC

- Ch. 2: intentionally use `{}` at first (rust-lang/book#3898)
- Inline fmt lints for `redirects/` (rust-lang/book#3897)
- ch12-03: `expect` is not used multitude times by this chapter (rust-lang/book#3287)
- Inline format args to `tools/src` (rust-lang/book#3896)
- Improve awkward phrasing around the kinds of closures (rust-lang/book#3290)
- Ch. 14: clarify workspace dependency reuse (rust-lang/book#3890)
- Edit on line no. 153. Replaced fn add_to_waitlist with fn eat_at_restaurant.  (rust-lang/book#3281)
- Ch. 2: less ambiguity about numbers (rust-lang/book#3895)
- Clarified first slices paragraph (rust-lang/book#3363)
- Inline all format arguments (rust-lang/book#3385)
- Use v1.58 captured ident formatting in examples (rust-lang/book#3048)
- Revert "ch18-03: Guarded match arm exhaustivness clarification" (rust-lang/book#3894)
- Ch. 18: further clarify about irrefutable patterns (rust-lang/book#3893)
- ch18-02: Minor corrections (rust-lang/book#3381)
- Make style of listings 9-7 and 9-8 consistent with 9-6 (rust-lang/book#3217)
- ch18-03: Guarded match arm exhaustivness clarification (rust-lang/book#3397)
- ch11-03: Unnecessary import removal (rust-lang/book#3284)
- Update ch20-01-single-threaded.md (rust-lang/book#3394)
- In Appendix D, adds hyperlink to Appendix E (rust-lang/book#3418)
- Chapter 13-03 fixed Iterator 'type' to 'trait' (rust-lang/book#3433)
- Fix the expected substring in ch11-01 (rust-lang/book#3534)
- Ch. 17: clarify 'in order to compile' (rust-lang/book#3892)
- Revert "Chapter 15-05: Fix incorrect interpretation of compiler error" (rust-lang/book#3891)
- Chapter 15-05: Fix incorrect interpretation of compiler error (rust-lang/book#3501)
- Remove direction to authenticate with `cargo login {API token}` (rust-lang/book#3506)
- Update syn dependencies in Chapter 19 to 2.0 (rust-lang/book#3888)
- Chapter 3: Clarify `return` vs. `break`. (rust-lang/book#3889)
- Fix "`Display` type" to "`Display` trait" in ch19-03 (rust-lang/book#3835)
- Update listings in ch 11-01 to reflect current output from cargo new (rust-lang/book#3533)
- Fix "`test` module" to "`tests` module" in ch11-03 (rust-lang/book#3579)
- Ch. 2: fix wording about `cargo update` (rust-lang/book#3882)
- Remove hebrew niqqud in 8-14 String::from example (rust-lang/book#3648)
- Ch. 16: fix a grammar issue (rust-lang/book#3881)
- Update MSVC instructions (rust-lang/book#3616)
- Replace RLS with rust-analyzer in ch00 (rust-lang/book#3546)
- Fix em dashes (rust-lang/book#3570)
- Revert rust-lang#3711 (rust-lang/book#3880)
- Procedure Macro: Update dependencies  (rust-lang/book#3631)
- Parity with rustup's help (rust-lang/book#3642)
- Fix confusing sentence (rust-lang/book#3877)
- Ch. 7: add a note about the need for `pub` in one more place (rust-lang/book#3879)

## rust-lang/edition-guide

2 commits in eb3eb80e106d03250c1fb7c5666b1c8c59672862..0c68e90acaae5a611f8f5098a3c2980de9845ab2
2024-04-16 21:23:55 UTC to 2024-04-15 16:05:32 UTC

- Document RustcEncodable/RustcDecodable (rust-lang/edition-guide#298)
- Flesh out detail behind disallowing refs to static mut (rust-lang/edition-guide#299)

## rust-lang/reference

5 commits in 55694913b1301cc809f9bf4a1ad1b3d6920efbd9..5854fcc286557ad3ab34d325073d11d8118096b6
2024-04-21 13:47:07 UTC to 2024-04-15 16:12:40 UTC

- Stabilize Wasm target features that are in phase 4 and 5 (rust-lang/reference#1420)
- Expand and clarify primitive alignment (rust-lang/reference#1493)
- Update clone reference to include closures (rust-lang/reference#1492)
- Document how `non_exhaustive` interacts with tuple and unit-like structs. (rust-lang/reference#1491)
- Fix link to RISC-V Zkt spec; it was pointing to Zkr (rust-lang/reference#1490)

## rust-lang/rustc-dev-guide

4 commits in b77a34bd46399687b4ce6a17198e9f316c988794..07425fed36b00e60341c5e29e28d37d40cbd4451
2024-04-13 15:16:44 UTC to 2024-04-08 19:00:54 UTC

- Add a note about checks with multiple revisions (rust-lang/rustc-dev-guide#1963)
- compiletest: clarify that headers must be one header per line (rust-lang/rustc-dev-guide#1962)
- chore: fix some typos in conments (rust-lang/rustc-dev-guide#1961)
- compiletest: specify which special env var and which particular CI job (rust-lang/rustc-dev-guide#1960)