[GSoC] Rust: Compiling the alloc crate - Status Report 3

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Project / Subsystem

gcc / rust

Date

2026-07-01

Proposer

Enes Cevik <enes@nsvke.com>

Source type

public_inbox

Consensus

Proposed

Sentiment

—/10

Technical tradeoffs

• Refactoring fat pointers to use static vtables ensures size consistency but requires careful migration and validation.
• Implementing intrinsics requires deep understanding of both Rust semantics and compiler internals.
• Addressing the `where` clause issue is critical for supporting dynamic dispatch and trait objects, but may require significant compiler changes.

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All attributes

project: gcc
subsystem: rust
patch_id: —
discussion_id: cb0952be08e2608e29e4d10543677fda@purelymail.com
source_type: public_inbox
title: [GSoC] Rust: Compiling the alloc crate - Status Report 3
headline: Rust: Compiling the alloc crate - Status Report 3
tldr: Progress report on compiling Rust's 'alloc' crate with GCCRS, detailing refactoring, intrinsic implementation, and unblocking issues.
proposer: Enes Cevik <enes@nsvke.com>
consensus: Proposed
outcome: proposed
sentiment_score: —
technical_tradeoffs: • Refactoring fat pointers to use static vtables ensures size consistency but requires careful migration and validation.
• Implementing intrinsics requires deep understanding of both Rust semantics and compiler internals.
• Addressing the `where` clause issue is critical for supporting dynamic dispatch and trait objects, but may require significant compiler changes.
series_id: —
series_role: standalone
series_parts: []
tags: • gcc
• rust
• GCCRS
• alloc
• compiler
url: https://inbox.sourceware.org/gcc/cb0952be08e2608e29e4d10543677fda@purelymail.com
bugzilla_url: —
date: 2026-07-01T00:00:00.000Z

[GSoC] Rust: Compiling the alloc crate - Status Report 3

Enes Cevik’s third status report on compiling Rust’s ‘alloc’ crate with GCCRS outlines progress and current challenges. Key achievements include refactoring the fat pointer structure to use a static struct for vtables, ensuring a consistent two-word size for fat pointers. This enabled the implementation of ‘size_of_val’ and ‘min_align_of_val’ intrinsics. A bug in trait method dispatch was fixed. However, progress on ‘coerce_unsized’ is blocked by an issue with the compiler ignoring where clauses in impl blocks, which is currently under investigation. As a workaround, ‘write_bytes’ and ‘arith_offset’ intrinsics have been implemented.