rustc-dev-guide subtree update

src/doc/rustc-dev-guide/rust-version

@@ -1 +1 @@
-2f3f27bf79ec147fec9d2e7980605307a74067f4
+9f32ccf35fb877270bc44a86a126440f04d676d0

src/doc/rustc-dev-guide/src/SUMMARY.md

@@ -108,6 +108,7 @@
     - [Installation](./autodiff/installation.md)
     - [How to debug](./autodiff/debugging.md)
     - [Autodiff flags](./autodiff/flags.md)
+    - [Type Trees](./autodiff/type-trees.md)
 
 # Source Code Representation
 

src/doc/rustc-dev-guide/src/about-this-guide.md

@@ -48,9 +48,9 @@ In addition, many of the ideas discussed throughout this guide are idealized des
 that are not fully realized yet.
 All this makes keeping this guide completely up to date on everything very hard!
 
-The Guide itself is of course open-source as well,
-and the sources can be found at the [GitHub repository].
-If you find any mistakes in the guide, please file an issue about it.
+The guide itself is of course open source as well,
+and the sources are hosted on [a GitHub repository].
+If you find any mistakes in the guide, please file an issue.
 Even better, open a PR with a correction!
 
 If you do contribute to the guide,
@@ -105,7 +105,7 @@ You might also find the following sites useful:
 [cheatsheet]: https://bors.rust-lang.org/
 [Miri]: https://github.com/rust-lang/miri
 [@bors]: https://github.com/bors
-[GitHub repository]: https://github.com/rust-lang/rustc-dev-guide/
+[a GitHub repository]: https://github.com/rust-lang/rustc-dev-guide/
 [rustc API docs]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle
 [Forge]: https://forge.rust-lang.org/
 [compiler-team]: https://github.com/rust-lang/compiler-team/

src/doc/rustc-dev-guide/src/appendix/glossary.md

@@ -68,6 +68,7 @@ Term                                                  | Meaning
 <span id="rib">rib</span>                      |  A data structure in the name resolver that keeps track of a single scope for names. ([see more](../name-resolution.md))
 <span id="rpit">RPIT</span>                    |  A return-position `impl Trait`. ([see the reference](https://doc.rust-lang.org/reference/types/impl-trait.html#abstract-return-types)).
 <span id="rpitit">RPITIT</span>                |  A return-position `impl Trait` in trait. Unlike RPIT, this is desugared to a generic associated type (GAT). Introduced in [RFC 3425](https://rust-lang.github.io/rfcs/3425-return-position-impl-trait-in-traits.html). ([see more](../return-position-impl-trait-in-trait.md))
+<span id="rustbuild">rustbuild</span>          |  A deprecated term for the part of bootstrap that is written in Rust
 <span id="scrutinee">scrutinee</span>          |  A scrutinee is the expression that is matched on in `match` expressions and similar pattern matching constructs. For example, in `match x { A => 1, B => 2 }`, the expression `x` is the scrutinee.
 <span id="sess">`sess`</span>                  |  The compiler _session_, which stores global data used throughout compilation
 <span id="side-tables">side tables</span>      |  Because the [AST](#ast) and HIR are immutable once created, we often carry extra information about them in the form of hashtables, indexed by the id of a particular node.

src/doc/rustc-dev-guide/src/autodiff/type-trees.md

@@ -0,0 +1,193 @@
+# TypeTrees for Autodiff
+
+## What are TypeTrees?
+Memory layout descriptors for Enzyme. Tell Enzyme exactly how types are structured in memory so it can compute derivatives efficiently.
+
+## Structure
+```rust
+TypeTree(Vec<Type>)
+
+Type {
+    offset: isize,  // byte offset (-1 = everywhere)
+    size: usize,    // size in bytes
+    kind: Kind,     // Float, Integer, Pointer, etc.
+    child: TypeTree // nested structure
+}
+```
+
+## Example: `fn compute(x: &f32, data: &[f32]) -> f32`
+
+**Input 0: `x: &f32`**
+```rust
+TypeTree(vec![Type {
+    offset: -1, size: 8, kind: Pointer,
+    child: TypeTree(vec![Type {
+        offset: 0, size: 4, kind: Float,  // Single value: use offset 0
+        child: TypeTree::new()
+    }])
+}])
+```
+
+**Input 1: `data: &[f32]`**
+```rust
+TypeTree(vec![Type {
+    offset: -1, size: 8, kind: Pointer,
+    child: TypeTree(vec![Type {
+        offset: -1, size: 4, kind: Float,  // -1 = all elements
+        child: TypeTree::new()
+    }])
+}])
+```
+
+**Output: `f32`**
+```rust
+TypeTree(vec![Type {
+    offset: 0, size: 4, kind: Float,  // Single scalar: use offset 0
+    child: TypeTree::new()
+}])
+```
+
+## Why Needed?
+- Enzyme can't deduce complex type layouts from LLVM IR
+- Prevents slow memory pattern analysis
+- Enables correct derivative computation for nested structures
+- Tells Enzyme which bytes are differentiable vs metadata
+
+## What Enzyme Does With This Information:
+
+Without TypeTrees:
+```llvm
+; Enzyme sees generic LLVM IR:
+define float @distance(ptr %p1, ptr %p2) {
+; Has to guess what these pointers point to
+; Slow analysis of all memory operations
+; May miss optimization opportunities
+}
+```
+
+With TypeTrees:
+```llvm
+define "enzyme_type"="{[-1]:Float@float}" float @distance(
+    ptr "enzyme_type"="{[-1]:Pointer, [-1,0]:Float@float}" %p1, 
+    ptr "enzyme_type"="{[-1]:Pointer, [-1,0]:Float@float}" %p2
+) {
+; Enzyme knows exact type layout
+; Can generate efficient derivative code directly
+}
+```
+
+# TypeTrees - Offset and -1 Explained
+
+## Type Structure
+
+```rust
+Type {
+    offset: isize, // WHERE this type starts
+    size: usize,   // HOW BIG this type is
+    kind: Kind,    // WHAT KIND of data (Float, Int, Pointer)
+    child: TypeTree // WHAT'S INSIDE (for pointers/containers)
+}
+```
+
+## Offset Values
+
+### Regular Offset (0, 4, 8, etc.)
+**Specific byte position within a structure**
+
+```rust
+struct Point {
+    x: f32, // offset 0, size 4
+    y: f32, // offset 4, size 4
+    id: i32, // offset 8, size 4
+}
+```
+
+TypeTree for `&Point` (internal representation):
+```rust
+TypeTree(vec![
+    Type { offset: 0, size: 4, kind: Float },   // x at byte 0
+    Type { offset: 4, size: 4, kind: Float },   // y at byte 4
+    Type { offset: 8, size: 4, kind: Integer }  // id at byte 8
+])
+```
+
+Generates LLVM
+```llvm
+"enzyme_type"="{[-1]:Pointer, [-1,0]:Float@float, [-1,4]:Float@float, [-1,8]:Integer, [-1,9]:Integer, [-1,10]:Integer, [-1,11]:Integer}"
+```
+
+### Offset -1 (Special: "Everywhere")
+**Means "this pattern repeats for ALL elements"**
+
+#### Example 1: Direct Array `[f32; 100]` (no pointer indirection)
+```rust
+TypeTree(vec![Type {
+    offset: -1, // ALL positions
+    size: 4,    // each f32 is 4 bytes
+    kind: Float, // every element is float
+}])
+```
+
+Generates LLVM: `"enzyme_type"="{[-1]:Float@float}"`
+
+#### Example 1b: Array Reference `&[f32; 100]` (with pointer indirection)  
+```rust
+TypeTree(vec![Type {
+    offset: -1, size: 8, kind: Pointer,
+    child: TypeTree(vec![Type {
+        offset: -1, // ALL array elements
+        size: 4,    // each f32 is 4 bytes
+        kind: Float, // every element is float
+    }])
+}])
+```
+
+Generates LLVM: `"enzyme_type"="{[-1]:Pointer, [-1,-1]:Float@float}"`
+
+Instead of listing 100 separate Types with offsets `0,4,8,12...396`
+
+#### Example 2: Slice `&[i32]`
+```rust
+// Pointer to slice data
+TypeTree(vec![Type {
+    offset: -1, size: 8, kind: Pointer,
+    child: TypeTree(vec![Type {
+        offset: -1, // ALL slice elements
+        size: 4,    // each i32 is 4 bytes
+        kind: Integer
+    }])
+}])
+```
+
+Generates LLVM: `"enzyme_type"="{[-1]:Pointer, [-1,-1]:Integer}"`
+
+#### Example 3: Mixed Structure
+```rust
+struct Container {
+    header: i64,        // offset 0
+    data: [f32; 1000],  // offset 8, but elements use -1
+}
+```
+
+```rust
+TypeTree(vec![
+    Type { offset: 0, size: 8, kind: Integer }, // header
+    Type { offset: 8, size: 4000, kind: Pointer,
+        child: TypeTree(vec![Type {
+            offset: -1, size: 4, kind: Float // ALL array elements
+        }])
+    }
+])
+```
+
+## Key Distinction: Single Values vs Arrays
+
+**Single Values** use offset `0` for precision:
+- `&f32` has exactly one f32 value at offset 0
+- More precise than using -1 ("everywhere")  
+- Generates: `{[-1]:Pointer, [-1,0]:Float@float}`
+
+**Arrays** use offset `-1` for efficiency:
+- `&[f32; 100]` has the same pattern repeated 100 times
+- Using -1 avoids listing 100 separate offsets
+- Generates: `{[-1]:Pointer, [-1,-1]:Float@float}`

src/doc/rustc-dev-guide/src/building/bootstrapping/writing-tools-in-bootstrap.md

@@ -3,18 +3,32 @@
 There are three types of tools you can write in bootstrap:
 
 - **`Mode::ToolBootstrap`**
+
   Use this for tools that don’t need anything from the in-tree compiler and can run with the stage0 `rustc`.
-  The output is placed in the "bootstrap-tools" directory. This mode is for general-purpose tools built
-  entirely with the stage0 compiler, including target libraries and only works for stage 0.
+  The output is placed in the "bootstrap-tools" directory.
+  This mode is for general-purpose tools built entirely with the stage0 compiler,
+  including target libraries, and it only works for stage 0.
 
 - **`Mode::ToolStd`**
-  Use this for tools that rely on the locally built std. The output goes into the "stageN-tools" directory.
+
+  Use this for tools that rely on the locally built std.
+  The output goes into the "stageN-tools" directory.
   This mode is rarely used, mainly for `compiletest` which requires `libtest`.
 
 - **`Mode::ToolRustcPrivate`**
-  Use this for tools that use the `rustc_private` mechanism, and thus depend on the locally built `rustc` and its rlib artifacts. This is more complex than the other modes because the tool must be built with the same compiler used for `rustc` and placed in the "stageN-tools" directory. When you choose `Mode::ToolRustcPrivate`, `ToolBuild` implementation takes care of this automatically. If you need to use the builder’s compiler for something specific, you can get it from `ToolBuildResult`, which is
-  returned by the tool's [`Step`].
 
-Regardless of the tool type you must return `ToolBuildResult` from the tool’s [`Step`] implementation and use `ToolBuild` inside it.
+  Use this for tools that use the `rustc_private` mechanism,
+  and thus depend on the locally built `rustc` and its rlib artifacts.
+  This is more complex than the other modes,
+  because the tool must be built with the same compiler used for `rustc`,
+  and placed in the "stageN-tools" directory.
+  When you choose `Mode::ToolRustcPrivate`,
+  `ToolBuild` implementation takes care of this automatically.
+  If you need to use the builder’s compiler for something specific,
+  you can get it from `ToolBuildResult`, which is returned by the tool's [`Step`].
+
+Regardless of the tool type,
+you must return `ToolBuildResult` from the tool’s [`Step`] implementation,
+and use `ToolBuild` inside it.
 
 [`Step`]: https://doc.rust-lang.org/nightly/nightly-rustc/bootstrap/core/builder/trait.Step.html

src/doc/rustc-dev-guide/src/building/how-to-build-and-run.md

@@ -149,7 +149,7 @@ On Windows, the Powershell commands may give you an error that looks like this:
 ```
 PS C:\Users\vboxuser\rust> ./x
 ./x : File C:\Users\vboxuser\rust\x.ps1 cannot be loaded because running scripts is disabled on this system. For more
-information, see about_Execution_Policies at https:/go.microsoft.com/fwlink/?LinkID=135170.
+information, see about_Execution_Policies at https://go.microsoft.com/fwlink/?LinkID=135170.
 At line:1 char:1
 + ./x
 + ~~~

src/doc/rustc-dev-guide/src/compiler-team.md

@@ -1,10 +1,14 @@
 # About the compiler team
 
+> NOTE:
+> There exists much detail about the team [on Forge], making most of the following obsolete.
+
 rustc is maintained by the [Rust compiler team][team]. The people who belong to
 this team collectively work to track regressions and implement new features.
 Members of the Rust compiler team are people who have made significant
 contributions to rustc and its design.
 
+[on Forge]: https://forge.rust-lang.org/compiler
 [team]: https://www.rust-lang.org/governance/teams/compiler
 
 ## Discussion

src/doc/rustc-dev-guide/src/fuzzing.md

@@ -90,14 +90,15 @@ Here are a few things you can do to help the Rust project after filing an ICE.
   triggering the ICE, such as syntax errors or borrow-checking errors
 - Minimize the test case (see below). If successful, you can label the
   issue with `S-has-mcve`. Otherwise, you can apply `E-needs-mcve`.
-- Add the minimal test case to the rust-lang/rust repo as a [crashes test].
+- Add the minimal test case to the rust-lang/rust repo as a [crash test].
   While you're at it, consider including other "untracked" crashes in your PR.
-  Please don't forget to mark your issue with `S-bug-has-test` afterwards.
+  Please don't forget to mark all relevant issues with `S-bug-has-test` once
+  your PR is merged.
 
 See also [applying and removing labels][labeling].
 
 [bisect]: https://rust-lang.github.io/cargo-bisect-rustc/
-[crashes test]: tests/compiletest.html#crashes-tests
+[crash test]: tests/compiletest.html#crash-tests
 [labeling]: https://forge.rust-lang.org/release/issue-triaging.html#applying-and-removing-labels
 
 ## Minimization

src/doc/rustc-dev-guide/src/profiling/with_perf.md

@@ -4,8 +4,7 @@ This is a guide for how to profile rustc with [perf](https://perf.wiki.kernel.or
 
 ## Initial steps
 
-- Get a clean checkout of rust-lang/master, or whatever it is you want
-  to profile.
+- Get a clean checkout of rust-lang/rust
 - Set the following settings in your `bootstrap.toml`:
   - `rust.debuginfo-level = 1` - enables line debuginfo
   - `rust.jemalloc = false` - lets you do memory use profiling with valgrind

src/doc/rustc-dev-guide/src/tests/best-practices.md

@@ -71,7 +71,7 @@ related tests.
 > //! Regression test for <https://github.com/rust-lang/rust/issues/123456>.
 > ```
 >
-> One exception to this rule is [crashes tests]: there it is canonical that
+> One exception to this rule is [crash tests]: there it is canonical that
 > tests are named only after issue numbers because its purpose is to track
 > snippets from which issues no longer ICE/crash, and they would either be
 > removed or converted into proper ui/other tests in the fix PRs.
@@ -199,4 +199,4 @@ See [LLVM FileCheck guide][FileCheck] for details.
 [compiletest directives]: ./directives.md
 [`run-make`]: ./compiletest.md#run-make-tests
 [FileCheck]: https://llvm.org/docs/CommandGuide/FileCheck.html
-[crashes tests]: ./compiletest.md#crashes-tests
+[crash tests]: ./compiletest.md#crash-tests