build-std: context

text/0000-build-std/0-introduction.md

@@ -0,0 +1,87 @@
+- Feature Name: `build-std`
+- Start Date: 2025-06-05
+- RFC PR: [rust-lang/rfcs#0000](https://github.com/rust-lang/rfcs/pull/0000)
+- Rust Issue: [rust-lang/rust#0000](https://github.com/rust-lang/rust/issues/0000)
+
+# Summary
+[summary]: #summary
+
+While Rust's pre-built standard library has proven itself sufficient for the
+majority of use cases, there are a handful of use cases that are not well
+supported:
+
+1. Rebuilding the standard library to match the user's profile
+2. Rebuilding the standard library with ABI-modifying flags
+3. Building the standard library for tier three targets
+
+This RFC is co-authored by [David Wood][davidtwco] and
+[Adam Gemmell][adamgemmell]. To improve the readability of this RFC, it does not
+follow the standard RFC template, while still aiming to capture all of the
+salient details that the template encourages. Due to the length of this RFC, it
+is split over multiple files to avoid rendering issues and slow loading on some
+platforms.
+
+### Scope
+[scope]: #scope
+
+build-std, as proposed by this RFC, has many restrictions and limitations that
+mean it will not support most use cases that those waiting for build-std hope
+that it will. This is an explicit and deliberate choice.
+
+This RFC will focus on resolving the key questions that will enable a MVP of
+build-std to be accepted and stabilised. This will lay the foundation for future
+proposals to lift restrictions and enable build-std to support more use cases,
+without those proposals having to survey the ten+ years of issues, pull requests
+and discussion that this RFC has.
+
+As a general rule, this RFC tries to answer the question "what crates of the
+standard library get built and when do they get built" and considers anything
+else as likely out-of-scope.
+
+### Terminology
+[terminology]: #terminology
+
+The following terminology is used throughout the RFC:
+
+- "the standard library" is used to refer to all of the crates that comprise the
+  standard library - `core`, `alloc` and `std`
+- "std" is used to refer only to the `std` crate, not the entirety of the standard
+  library
+
+# Contents
+[contents]: #contents
+
+This RFC has the following contents:
+
+1. [Summary][summary] (you are here)
+
+    - Introduction to the proposal, its scope, terminology/conventions used and
+      the structure of the RFC
+
+2. [Background](./1-background.md)
+
+    - Detailed explanations of how relevant and impacted parts of the Rust
+      toolchain currently work
+
+3. [History](./2-history.md)
+
+    - Chronological summary of the various proposals and discussions that have
+      taken place relating to the ability to rebuild the standard library, and
+      of the current experimental implementation in Cargo
+
+4. [Motivation](./3-motivation.md)
+
+    - Descriptions of the varied problems that build-std has been proposed as a
+      solution to
+
+5. [Appendix II: Exhaustive literature review](./4-appendix-literature-review.md)
+
+    - More detailed summaries of the relevant issues, discussions, pull requests
+      and proposals that comprise the history of the build-std feature since
+      2015
+
+    - [*History*](./2-history.md) aims to summarise this content further and
+      cover everything that should be necessary to understand the proposal
+
+[davidtwco]: https://github.com/davidtwco
+[adamgemmell]: https://github.com/adamgemmell