--- title: How the Rust compiler actually works | daily.dev description: This video traces a Rust program through the full compilation pipeline, from source code to a running executable. A function that doubles a value under 100 is... canonical: https://daily.dev/posts/how-the-rust-compiler-actually-works-t4jmcttky twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How the Rust compiler actually works | daily.dev og:description: This video traces a Rust program through the full compilation pipeline, from source code to a running executable. A function that doubles a value under 100 is... og:url: https://daily.dev/posts/how-the-rust-compiler-actually-works-t4jmcttky og:image: https://api.daily.dev/og/posts/T4JmcTtkY.png og:image:alt: How the Rust compiler actually works og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # How the Rust compiler actually works **[Let's Get Rusty](https://daily.dev/sources/letsgetrusty)** · 4 min read · 0 upvotes · 0 comments ## Summary This video traces a Rust program through the full compilation pipeline, from source code to a running executable. A function that doubles a value under 100 is followed through each stage. Cargo invokes rustc, which parses and type-checks the code, then lowers it to MIR, the mid-level intermediate representation. The borrow checker tracks which values are moved or borrowed along each execution path. MIR is then lowered to LLVM IR, which LLVM turns into object code for the chosen target. A linker combines the object code with dependencies into a final executable, which cargo run launches to produce the answer 42. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What are the main stages a Rust program goes through when compiled with cargo build? Cargo invokes rustc, which parses, resolves names, and type-checks the source before lowering it to MIR (mid-level intermediate representation). The borrow checker analyzes MIR for move and borrow issues, then MIR is lowered to LLVM IR. LLVM's backend compiles that IR into target-specific object code, and a linker combines it with dependencies into the final executable that cargo run executes. _Tracing this pipeline on daily.dev helps when a cryptic rustc error sends you hunting for the actual cause._ ### What is MIR in the Rust compiler and why does it exist? MIR (mid-level intermediate representation) is the form rustc lowers Rust source code into after parsing, name resolution, and type checking. It breaks Rust's many language features down into a smaller set of simpler operations, such as comparisons and branch choices, making the code easier to analyze. The Rust borrow checker runs its move and borrow analysis directly on MIR. _Understanding MIR helps when borrow checker errors on daily.dev readers' own code feel opaque._ ### Why can the same Rust source code be compiled for different CPU architectures? Rust source lowers to LLVM IR, a representation shared by languages like Rust, C, and C++, which LLVM can optimize generically before its backend picks specific instructions for the chosen target CPU. The LLVM backend then translates that IR into object code and assembly tailored to the target, letting one source file produce binaries for different processors. _Knowing how LLVM targets different CPUs matters when deciding on cross-compilation for a Rust project._ ## Similar posts on daily.dev - [2026 is an exciting year for the Rust compiler \(and me\)](https://daily.dev/posts/2026-is-an-exciting-year-for-the-rust-compiler-and-me--52dhmmibn) · Hacker News · 0 upvotes · 0 comments - [How Rust IDEs Understand Code](https://daily.dev/posts/how-rust-ides-understand-code-yfytlpwlu) · JetBrains · 46 upvotes · 15 comments - [A look at Rust from 2012](https://daily.dev/posts/a-look-at-rust-from-2012-2wlds6cew) · Lobsters · 1 upvotes · 0 comments --- Tags: [#general-programming](https://daily.dev/tags/general-programming), [#rust](https://daily.dev/tags/rust) [View this post on daily.dev](https://daily.dev/posts/how-the-rust-compiler-actually-works-t4jmcttky) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"How the Rust compiler actually works","url":"https://daily.dev/posts/how-the-rust-compiler-actually-works-t4jmcttky","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-the-rust-compiler-actually-works-t4jmcttky"},"datePublished":"2026-10-26T16:17:32.502Z","dateModified":"2026-10-26T16:17:56.312Z","description":"This video traces a Rust program through the full compilation pipeline, from source code to a running executable. A function that doubles a value under 100 is...","image":"https://i.ytimg.com/vi/QxoljOSBMrc/sddefault.jpg","thumbnailUrl":"https://i.ytimg.com/vi/QxoljOSBMrc/sddefault.jpg","isAccessibleForFree":true,"articleSection":"Let's Get Rusty","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Let's Get Rusty","logo":"https://media.daily.dev/image/upload/s--iqd05ejH--/f_auto/v1725035314/logos/letsgetrusty","url":"https://daily.dev/sources/letsgetrusty"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/how-the-rust-compiler-actually-works-t4jmcttky","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"general-programming,rust","timeRequired":"PT4M","video":{"@type":"VideoObject","name":"How the Rust compiler actually works","description":"This video traces a Rust program through the full compilation pipeline, from source code to a running executable. A function that doubles a value under 100 is...","thumbnailUrl":"https://i.ytimg.com/vi/QxoljOSBMrc/sddefault.jpg","uploadDate":"2026-10-26T16:17:32.502Z","duration":"PT4M","url":"https://api.daily.dev/r/T4JmcTtkY","embedUrl":"https://www.youtube.com/embed/QxoljOSBMrc"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Let's Get Rusty","item":"https://daily.dev/sources/letsgetrusty"},{"@type":"ListItem","position":3,"name":"How the Rust compiler actually works"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/how-the-rust-compiler-actually-works-t4jmcttky#faq","mainEntity":[{"@type":"Question","name":"What are the main stages a Rust program goes through when compiled with cargo build?","acceptedAnswer":{"@type":"Answer","text":"Cargo invokes rustc, which parses, resolves names, and type-checks the source before lowering it to MIR (mid-level intermediate representation). The borrow checker analyzes MIR for move and borrow issues, then MIR is lowered to LLVM IR. LLVM's backend compiles that IR into target-specific object code, and a linker combines it with dependencies into the final executable that cargo run executes. Tracing this pipeline on daily.dev helps when a cryptic rustc error sends you hunting for the actual cause."}},{"@type":"Question","name":"What is MIR in the Rust compiler and why does it exist?","acceptedAnswer":{"@type":"Answer","text":"MIR (mid-level intermediate representation) is the form rustc lowers Rust source code into after parsing, name resolution, and type checking. It breaks Rust's many language features down into a smaller set of simpler operations, such as comparisons and branch choices, making the code easier to analyze. The Rust borrow checker runs its move and borrow analysis directly on MIR. Understanding MIR helps when borrow checker errors on daily.dev readers' own code feel opaque."}},{"@type":"Question","name":"Why can the same Rust source code be compiled for different CPU architectures?","acceptedAnswer":{"@type":"Answer","text":"Rust source lowers to LLVM IR, a representation shared by languages like Rust, C, and C++, which LLVM can optimize generically before its backend picks specific instructions for the chosen target CPU. The LLVM backend then translates that IR into object code and assembly tailored to the target, letting one source file produce binaries for different processors. Knowing how LLVM targets different CPUs matters when deciding on cross-compilation for a Rust project."}}]} ```