refactor: modularize build core engine, update workspaces, cache, and test suite

2026-10-21 12:38:30 +00:00 · 2026-07-18 20:02:12 +08:00
parent 9326e23a53
commit 9eaa4635d5
49 changed files with 3385 additions and 2312 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,5 @@ sandbox/**
 .env

 personal/
+.*
+!.gitignore
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,53 @@
 # Changelog

+## [0.8.0] - 2026-07-18 "Модульный Движок Сборки, Новая Архитектура Ядра и Улучшение Workspaces / Modular Build Engine, New Core Architecture, & Workspace Improvements"
+
+### RU
+
+**Добавлено:**
+
+- **Выделенное ядро сборки (Build Engine extraction)** — вся логика оркестрации компиляции и сборки полностью вынесена из интерфейсного модуля `src/cli/build.rs` в изолированный, переиспользуемый модуль ядра `src/core/build/engine.rs`.
+- **Полиморфная модель языков (Трейт `Language`)** — введение абстрактного трейта `Language` (`src/core/build/language/mod.rs`). Логика поиска файлов, сопоставления расширений и компиляторов распределена по выделенным языковым бэкендам для C, C++ (включая шаги генерации Qt), LLVM IR и ассемблера (GAS, NASM, FASM, MASM).
+- **Абстракция сборщиков (Трейт `Builder`)** — введение трейта `Builder` для полиморфного управления процессами компиляции (`src/core/build/builder/mod.rs`). Логика вызова компиляторов семейства GCC/Clang вынесена в общий модуль `builder/cc_common.rs`, а MSVC — в `builder/msvc/`.
+- **Поязыковая конфигурация (`[build.<lang>]`)** — добавлена поддержка индивидуальных настроек для каждого языка в `dcr.toml` (например, `[build.c]`, `[build.cpp]`, `[build.asm]`), позволяя независимо настраивать компилятор, стандарт и флаги сборки.
+- **Интеграция путей зависимостей в Workspaces** — сборщик теперь автоматически инжектирует пути заголовков (включая исходники `src/` членов, папки `include/` и директорию `target/include`) и библиотек (`target/lib`, а также специфичные для целевой платформы папки сборки) зависимых членов workspace при сборке.
+- **Система событий `BuildReporter`** — весь вывод сборщика переведён на событийную модель (`src/core/build/report.rs`), что делает движок пригодным для программного встраивания (например, в IDE) без необходимости перехвата stdout/stderr.
+- **Поддержка отмены сборки** — добавлен потокобезопасный токен отмены (`Arc<AtomicBool>`), позволяющий безопасно прервать выполнение компиляции на любом этапе.
+- **Сохранение кастомных ключей TOML** — парсер `dcr.toml` переведен на `toml_edit`, что гарантирует сохранение всех неизвестных/пользовательских ключей, комментариев и форматирования при перезаписи файла (например, через `dcr add`).
+- **Разрешение заголовков для локальных path-зависимостей** — исправлена проблема, при которой потребители не могли найти заголовочные файлы статических/динамических библиотек, лежащие в упакованной папке `target/include` локальных path-зависимостей.
+- **Новая система интеграционных тестов** — старый громоздкий файл `tests/cli_basic.rs` разделен на изолированные и структурированные интеграционные тесты для каждой команды и фичи: `cli_build.rs`, `cli_deps.rs`, `cli_lint.rs`, `cli_new.rs`, `cli_qt.rs`, `cli_test.rs`, `cli_workspace.rs`.
+
+**Изменено:**
+
+- **Дедупликация генерации артефактов** — логика линковки бинарных файлов (ELF, PE, EXE), динамических библиотек (`.so`, `.dll`, `.dylib`) и архивации статических библиотек (`.a`, `.lib`) полностью перенесена в выделенный модуль `src/core/build/builder/artifact.rs`.
+- **Запуск членов workspace из корня** — команда `dcr run` при вызове из корня workspace-only проекта теперь запускает сборку выбранного пакета в контексте workspace (через флаг `--workspace`), исключая изолированные ошибки сборки.
+- **Отказ от глобального состояния** — все операции сборки изолированы внутри структуры `BuildContext`, обеспечивая многопоточную безопасность сборщика.
+- **Вынос логики кэширования** — проверка инкрементальных изменений, отслеживание заголовков (`#include`) и вычисление хэшей сборки перенесено в изолированный модуль `src/core/build/cache.rs`.
+- **Модуляризация кастомных шагов** — обработка этапа `build.steps` для препроцессоров вынесена в `src/core/build/steps.rs`.
+
+### EN
+
+**Added:**
+
+- **Dedicated Build Engine (`src/core/build/engine.rs`)** — decoupled the build orchestration logic completely from the CLI front-end wrapper in `src/cli/build.rs` to a reusable, decoupled core build engine.
+- **Polymorphic Language Model (`Language` trait)** — introduced the abstract `Language` trait (`src/core/build/language/mod.rs`). File scanning, compiler resolution, and flags handling are now encapsulated in dedicated language modules for C, C++ (including Qt code generation), LLVM IR, and ASM (GAS, NASM, FASM, MASM).
+- **Polymorphic Compilation Dispatch (`Builder` trait)** — introduced the `Builder` trait to generalize builder invocations (`src/core/build/builder/mod.rs`). Consolidated GCC/Clang logic into `builder/cc_common.rs` and Microsoft Visual C++ logic into `builder/msvc/`.
+- **Per-Language Configuration overrides (`[build.<lang>]`)** — introduced support for configuring language-specific compiler, standard, and flags (e.g. `[build.c]`, `[build.cpp]`, `[build.asm]`) independently in `dcr.toml`.
+- **Automatic Workspace Dependency Injection** — during workspace builds, include/lib paths of dependent workspace members (including their source headers, local `include/` folders, and build target `target/include` / `target/lib` folders) are automatically resolved and injected.
+- **`BuildReporter` Event System** — decoupled build orchestration output into a structured event-driven reporter model (`src/core/build/report.rs`), making DCR suitable for library embedding and IDE integrations without stderr capturing.
+- **Build Cancellation Support** — introduced thread-safe cancellation tokens (`Arc<AtomicBool>`) allowing clients to safely abort compile runs mid-execution.
+- **TOML Formatting & Custom Keys Preservation** — migrated the config editor to `toml_edit`, preserving all unknown/user-defined TOML keys, structures, and comments during file write operations (e.g., in `dcr add`).
+- **Path Dependencies Target Include Resolution** — local path dependencies configured via tables now correctly expose headers built and packaged into their `target/include` folder to consumer packages.
+- **Modular Integration Test Suite** — refactored the monolith `tests/cli_basic.rs` file into clean, specialized integration tests: `cli_build.rs`, `cli_deps.rs`, `cli_lint.rs`, `cli_new.rs`, `cli_qt.rs`, `cli_test.rs`, `cli_workspace.rs`.
+
+**Changed:**
+
+- **Consolidated Linking and Archiving** — artifact generation (linking executables/shared libraries and archiving static libraries) consolidated into a single `src/core/build/builder/artifact.rs` module.
+- **Workspace-Aware member execution** — `dcr run` executed at the workspace root of a `workspace_only` project now triggers the member build inside the workspace context using the `--workspace` parameter, preventing standalone build issues.
+- **Elimination of Global State** — removed global variables and states from the build core, encapsulating build logic inside isolated `BuildContext` structs for thread safety.
+- **Build Cache Separation** — relocated mtime tracking, incremental caching, and header-dependency checking logic to `src/core/build/cache.rs`.
+- **Modularized Pre-build Steps** — decoupled generator scripts and pre-build commands parsing into `src/core/build/steps.rs`.
+
 ## [0.7.4] - 2026-06-17 "Qt Поддержка, Linting и Рефакторинг Архитектуры / Qt Support, Linting, & Architecture Refactor"

 ### RU
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -98,7 +98,7 @@ dependencies = [

 [[package]]
 name = "dcr"
-version = "0.7.4"
+version = "0.8.0"
 dependencies = [
 "ctrlc",
 "glob",
@@ -107,6 +107,7 @@ dependencies = [
 "serde_json",
 "sha2",
 "toml",
+ "toml_edit",
 "ureq",
 ]

@@ -703,12 +704,18 @@ dependencies = [
 "indexmap",
 "serde_core",
 "serde_spanned",
- "toml_datetime",
+ "toml_datetime 1.1.1+spec-1.1.0",
 "toml_parser",
 "toml_writer",
- "winnow",
+ "winnow 1.0.3",
 ]

+[[package]]
+name = "toml_datetime"
+version = "0.6.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22cddaf88f4fbc13c51aebbf5f8eceb5c7c5a9da2ac40a13519eb5b0a0e8f11c"
+
 [[package]]
 name = "toml_datetime"
 version = "1.1.1+spec-1.1.0"
@@ -718,15 +725,33 @@ dependencies = [
 "serde_core",
 ]

+[[package]]
+name = "toml_edit"
+version = "0.22.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41fe8c660ae4257887cf66394862d21dbca4a6ddd26f04a3560410406a2f819a"
+dependencies = [
+ "indexmap",
+ "toml_datetime 0.6.11",
+ "toml_write",
+ "winnow 0.7.15",
+]
+
 [[package]]
 name = "toml_parser"
 version = "1.1.2+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2abe9b86193656635d2411dc43050282ca48aa31c2451210f4202550afb7526"
 dependencies = [
- "winnow",
+ "winnow 1.0.3",
 ]

+[[package]]
+name = "toml_write"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d99f8c9a7727884afe522e9bd5edbfc91a3312b36a77b5fb8926e4c31a41801"
+
 [[package]]
 name = "toml_writer"
 version = "1.1.1+spec-1.1.0"
@@ -930,6 +955,15 @@ version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"

+[[package]]
+name = "winnow"
+version = "0.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df79d97927682d2fd8adb29682d1140b343be4ac0f08fd68b7765d9c059d3945"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "winnow"
 version = "1.0.3"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "dcr"
-version = "0.7.4"
+version = "0.8.0"
 edition = "2024"
 build = "build.rs"
 description = "DCR is a utility for managing C/C++ projects in a Cargo-like style."
@@ -66,6 +66,7 @@ serde = { version = "1", features = ["derive"] }
 self-replace = "1"
 sha2 = "0.10"
 toml = "1.0.3"
+toml_edit = "0.22"
 serde_json = "1"
 ctrlc = "3"

--- a/TODO.md
+++ b/TODO.md
@@ -23,8 +23,8 @@ Priority list of tasks to turn DCR into a true Cargo killer for C/C++ developers

 - [ ] **Static analysis** (`dcr check`)  
  Integration with clang-tidy, cppcheck, include-what-you-use
- [-] **Linter + Formatter** (`dcr fmt`, `dcr lint`)  
-  *`dcr fmt` (clang-format) implemented; `dcr lint` does not exist yet*
+- [x] **Linter + Formatter** (`dcr fmt`, `dcr lint`)  
+  *`dcr fmt` (clang-format) and `dcr lint` (clang-tidy) are implemented*
 - [ ] **Hot reload / Live reload** for applications (raylib, SFML, SDL, etc.)
 - [-] **Workspaces improvements** Per-member include directories, selective builds, better dependency graph  
  *Basic workspaces with dep ordering + topological sort work; advanced features missing*
--- a/docs/commands/project-commands.mdx
+++ b/docs/commands/project-commands.mdx
@@ -12,8 +12,12 @@ Only ASCII letters, digits, underscores `_` and hyphens `-` are allowed in the p

 ```bash
 dcr new my-app
+dcr new my-app --vcs none
 ```

+Flags:
+- `--vcs <git|none>` — Initialize version control system (defaults to `git` if available, or `none`).
+
 Generates:
 - `dcr.toml` with basic fields
 - `src/main.c` with a `main` template
@@ -23,8 +27,11 @@ Generates:
 Initializes a DCR project in the current (empty) directory.

 ```bash
-mkdir app && cd app
 dcr init
+dcr init --vcs none
 ```

+Flags:
+- `--vcs <git|none>` — Initialize version control system (defaults to `git` if available, or `none`).
+
 The project name is taken from the current directory name. The directory name must follow the same naming rules as `dcr new`.
--- a/docs/commands/system-commands.mdx
+++ b/docs/commands/system-commands.mdx
@@ -15,9 +15,9 @@ dcr setup
 If `~/.dcr/config.toml` is not found, DCR returns an error. Create it manually:

 ```toml
-[[registry]]
-name = "default"
+[registry.default]
 url = "https://index.dcr.pm"
+priority = 1
 ```

 ## `dcr --help`
--- a/docs/faq.mdx
+++ b/docs/faq.mdx
@@ -13,9 +13,9 @@ error: registry not found
 **Solution:** Make sure `~/.dcr/config.toml` exists:

 ```toml
-[[registry]]
-name = "default"
+[registry.default]
 url = "https://index.dcr.pm"
+priority = 1
 ```

 And check `DCR_INDEX_PATH`:
--- a/docs/getting-started/installation.mdx
+++ b/docs/getting-started/installation.mdx
@@ -100,7 +100,7 @@ man dcr-build
 To use the registry, create `~/.dcr/config.toml`:

 ```toml
-[[registry]]
-name = "default"
+[registry.default]
 url = "https://index.dcr.pm"
+priority = 1
 ```
--- a/docs/license.mdx
+++ b/docs/license.mdx
@@ -10,36 +10,23 @@ DCR itself is [GPL-3.0-or-later](https://spdx.org/licenses/GPL-3.0-or-later.html

 > **Note:** DCR is a build tool, not a library. The GPL applies only to DCR's own source code. Projects built with DCR are not subject to DCR's license — their licensing is determined solely by their own code and dependencies.

-## Vendored libraries
-
-DCR statically links the following C libraries through its vendored Rust dependencies:
-
-| Library | License | Bundled by |
-|---|---|---|
-| [libgit2](https://libgit2.org) | MIT OR Apache-2.0 | `git2` / `libgit2-sys` |
-| [libssh2](https://libssh2.org) | MIT OR Apache-2.0 | `libgit2-sys` |
-| [zlib](https://zlib.net) | MIT OR Apache-2.0 | `libgit2-sys` |
-| [OpenSSL](https://openssl.org) | Apache-2.0 | `openssl-sys` / `openssl-src` |
-| [ring](https://github.com/briansmith/ring) | Apache-2.0 AND ISC | `rustls` |
-
 ## Rust dependencies

 DCR is written in Rust. The following notable Rust crates are statically linked:

 | Crate | License |
 |---|---|
-| [`reqwest`](https://crates.io/crates/reqwest) | MIT OR Apache-2.0 |
-| [`rustls`](https://crates.io/crates/rustls) | Apache-2.0 OR ISC OR MIT |
+| [`ureq`](https://crates.io/crates/ureq) | MIT OR Apache-2.0 |
 | [`serde`](https://crates.io/crates/serde) | MIT OR Apache-2.0 |
 | [`toml`](https://crates.io/crates/toml) | MIT OR Apache-2.0 |
+| [`toml_edit`](https://crates.io/crates/toml_edit) | MIT OR Apache-2.0 |
+| [`serde_json`](https://crates.io/crates/serde_json) | MIT OR Apache-2.0 |
 | [`sha2`](https://crates.io/crates/sha2) | MIT OR Apache-2.0 |
-| [`git2`](https://crates.io/crates/git2) | MIT OR Apache-2.0 |
-| [`openssl`](https://crates.io/crates/openssl) | Apache-2.0 |
-| [`tokio`](https://crates.io/crates/tokio) | MIT |
-| [`hyper`](https://crates.io/crates/hyper) | MIT |
+| [`glob`](https://crates.io/crates/glob) | MIT OR Apache-2.0 |
+| [`self-replace`](https://crates.io/crates/self-replace) | MIT OR Apache-2.0 |
 | [`ctrlc`](https://crates.io/crates/ctrlc) | MIT OR Apache-2.0 |

-Full dependency tree (143 packages) is available in [`Cargo.lock`](https://github.com/dexoron/dcr/blob/main/Cargo.lock). The overwhelming majority are dual-licensed under MIT OR Apache-2.0.
+Full dependency tree is available in [`Cargo.lock`](https://github.com/dexoron/dcr/blob/main/Cargo.lock). The overwhelming majority are dual-licensed under MIT OR Apache-2.0.

 ## Additional credits

--- a/docs/recipes/multi-package-workspace.mdx
+++ b/docs/recipes/multi-package-workspace.mdx
@@ -34,6 +34,7 @@ type = "none"
 inherit = true
 language = "c"
 standard = "c11"
+workspace_only = true

 [workspace.lib-core]
 path = "lib-core"
--- a/docs/reference/dcr-toml.mdx
+++ b/docs/reference/dcr-toml.mdx
@@ -41,7 +41,7 @@ Main project configuration file. Located at the project root.
 |-------|----------|-------------|
 | `name` | yes | Project name |
 | `version` | yes | Semantic version |
-| `type` | yes | `app`, `lib`, `none` |
+| `type` | no | `app`, `lib`, `none` (defaults to `"none"`) |
 | `license` | no | SPDX license identifier |
 | `author` | no | Author |

@@ -62,10 +62,10 @@ author = "John Doe"

 | Field | Default | Description |
 |-------|---------|-------------|
-| `language` | `"c"` | `"c"`, `"c++"`, `"cpp"`, `"cxx"`, `"asm"` |
+| `language` | `"c"` | `"c"`, `"c++"`, `"cpp"`, `"cxx"`, `"asm"` (optional, defaults to `"c"`) |
 | `standard` | `"c11"` | C standard (`c11`, `c17`, `c23`) |
-| `cxx_standard` | `"c++20"` | C++ standard (`c++17`, `c++20`, `c++23`) |
-| `compiler` | `"clang"` | Preferred compiler |
+| `cxx_standard` | — | C++ standard (`c++17`, `c++20`, `c++23`) |
+| `compiler` | `"clang"` | Preferred compiler (optional, defaults to `"clang"`) |
 | `kind` | `"bin"` | `bin`, `staticlib`, `sharedlib`, `efi`, `elf`, `none`, `custom` |
 | `target` | host | Target triple for cross-compilation |
 | `platform` | `"native"` | `native`, `efi` |
@@ -80,13 +80,13 @@ author = "John Doe"
 | `inherit` | `false` | Inherit build from workspace root |
 | `clean` | `[]` | Glob patterns for custom clean paths |
 | `out_dir` | `""` | Custom output directory |
-| `workspace_only` | `false` | Workspace-only, not built standalone |
+| `workspace_only` | `false` | Workspace-only, not built standalone (no `language`/`compiler` required) |
 | `freestanding` | `false` | Compile in freestanding mode (`-ffreestanding` + `-nostdlib -static`) |
-| `opt_level` | `"0"` (debug) / `"3"` (release) | Optimization level: `0`-`3`, `"s"`, `"z"` |
-| `debug` | `true` (debug) / `false` (release) | Emit debug symbols (`-g`) |
+| `opt_level` | — | Optimization level: `0`-`3`, `"s"`, `"z"` (derived from profile if omitted) |
+| `debug` | profile-based | Emit debug symbols (`-g`): `true` in debug, `false` in release |
 | `lto` | `false` | Link-time optimization (`-flto` for both compiler and linker) |
 | `strip` | `false` | Strip symbols from output (`-s` in ldflags) |
-| `warnings` | `["all", "extra"]` (debug) / `[]` (release) | Warning flags (e.g. `"all"`, `"extra"`, `"pedantic"`) |
+| `warnings` | `[]` | Warning flags (e.g. `"all"`, `"extra"`, `"pedantic"`); engine adds `-Wall -Wextra` in debug if empty |
 | `panic` | `""` | Panic strategy: `"abort"` disables exceptions and unwind tables |
 | `codegen-units` | `""` | Max parallel compilation jobs (`"0"` = auto) |
 | `qt` | `false` | Enable automatic Qt meta-object handling (MOC, UIC, RCC) |
@@ -96,6 +96,30 @@ Settings from raw config (not in typed struct):
 - `ldscript` — linker script path
 - `build.steps` / `build.post_steps` — codegen steps

+## Per-language overrides: `[build.c]`, `[build.cxx]`, `[build.asm]`
+
+Each language can have its own table that overrides the flat `[build]` settings:
+
+```toml
+[build]
+compiler = "clang"
+standard = "c11"
+
+[build.c]
+standard = "c23"
+compiler = "gcc"
+
+[build.cxx]
+standard = "c++23"
+compiler = "g++"
+
+[build.asm]
+compiler = "nasm"
+flags = ["-felf64"]
+```
+
+The flat `[build]` acts as fallback; per-language tables take precedence for their language.
+
 Example:

 ```toml
--- a/docs/reference/dependencies.mdx
+++ b/docs/reference/dependencies.mdx
@@ -41,24 +41,22 @@ DCR uses a package registry for dependency lookup by name.

 ```toml
 # ~/.dcr/config.toml
-[[registry]]
-name = "default"
+[registry.default]
 url = "https://index.dcr.pm"
+priority = 1
 ```

 Registry priority: order in `config.toml`. The `DCR_INDEX_PATH` variable overrides the path to `index.json`.

 ## Git dependencies

-DCR clones git repositories via `git2`:
+Git dependencies are parsed and recorded in `dcr.lock`. DCR supports specifying branch/tag/rev for git sources:

 - `branch` — switch to a branch
 - `tag` — switch to a tag
 - `rev` — switch to a specific commit
 - `features` — feature flags (parsed, but does not affect build)

-Cache path: `~/.dcr/git/<hash>/`.
-
 ## Path dependencies

 Local paths. DCR automatically discovers include and lib directories from the neighbor's `dcr.toml`.
--- a/docs/reference/workspaces.mdx
+++ b/docs/reference/workspaces.mdx
@@ -65,3 +65,21 @@ standard = "c17"

 # member inherits language and standard
 ```
+
+## Workspace-only root (no build of its own)
+
+A workspace root can set `workspace_only = true` — it won't be built itself, and doesn't need `language` or `compiler`:
+
+```toml
+[package]
+name = "my-workspace"
+version = "0.1.0"
+
+[build]
+workspace_only = true
+kind = "bin"
+
+[workspace]
+lib-core = { path = "lib-core" }
+app = { path = "app", deps = ["lib-core"] }
+```
--- a/src/cli/add.rs
+++ b/src/cli/add.rs
@@ -45,7 +45,6 @@ pub fn add(args: &[String]) -> i32 {
        println!("    Adds a dependency to the project.");
        println!();
        printc("SOURCES:", BOLD_GREEN);
-        println!("    user/repo                 GitHub shorthand");
        println!("    github:user/repo          GitHub repository");
        println!("    gitlab:user/repo          GitLab repository");
        println!("    git:host.com/user/repo    Generic git repository");
@@ -140,7 +139,6 @@ fn parse_add_args(args: &[String]) -> Result<AddArgs, i32> {
    if args.is_empty() {
        error("Usage: dcr add <name> <source> [--branch <branch> | --tag <tag> | --rev <rev>]");
        error("Sources:");
-        error("  user/repo                 -> github.com/user/repo");
        error("  github:user/repo          -> github.com/user/repo");
        error("  gitlab:user/repo          -> gitlab.com/user/repo");
        error("  git:host.com/user/repo    -> host.com/user/repo");
--- a/src/cli/build.rs
+++ b/src/cli/build.rs
--- a/src/cli/gen.rs
+++ b/src/cli/gen.rs
@@ -15,10 +15,10 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

+use crate::core::build::builder::BuildContext;
+use crate::core::build::builder::collect_sources;
+use crate::core::build::common;
 use crate::core::build_config::Config;
-use crate::core::builder::BuildContext;
-use crate::core::builder::collect_sources;
-use crate::core::builder::common;
 use crate::core::workspace::parse_workspace;
 use crate::utils::build::{
    get_bool_with_profile, get_config_opt, get_config_str, get_language_with_profile_or_default,
--- a/src/cli/lint.rs
+++ b/src/cli/lint.rs
@@ -15,8 +15,8 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

+use crate::core::build::common;
 use crate::core::build_config::Config;
-use crate::core::builder::common;
 use crate::utils::build::{get_bool_with_profile, get_list_with_profile};
 use crate::utils::fs::find_project_root;
 use crate::utils::log::error;
--- a/src/cli/run.rs
+++ b/src/cli/run.rs
@@ -218,7 +218,14 @@ fn run_project(
        return Err("Cannot run library build".to_string());
    }

-    let build_status = build(&args_for_build(flags));
+    let build_status = if let Some(wroot) = workspace_root {
+        with_dir(wroot, || {
+            Ok(build(&args_for_workspace_build(flags, project_name)))
+        })
+        .unwrap_or(1)
+    } else {
+        build(&args_for_build(flags))
+    };
    let bin_path = crate::platform::bin_path(
        &flags.profile,
        project_name,
@@ -266,6 +273,36 @@ fn args_for_build(flags: &crate::cli::flags::BuildRunFlags) -> Vec<String> {
        args.push("--workspace".to_string());
        args.push(name.clone());
    }
+    if flags.force {
+        args.push("--force".to_string());
+    }
+    if flags.clean {
+        args.push("--clean".to_string());
+    }
+    if flags.verbose {
+        args.push("--verbose".to_string());
+    }
+    args
+}
+
+fn args_for_workspace_build(
+    flags: &crate::cli::flags::BuildRunFlags,
+    member_name: &str,
+) -> Vec<String> {
+    let mut args = Vec::new();
+    args.push(format!("--{}", flags.profile));
+    if let Some(ref target) = flags.target {
+        args.push("--target".to_string());
+        args.push(target.clone());
+    }
+    args.push("--workspace".to_string());
+    args.push(member_name.to_string());
+    if flags.force {
+        args.push("--force".to_string());
+    }
+    if flags.clean {
+        args.push("--clean".to_string());
+    }
    if flags.verbose {
        args.push("--verbose".to_string());
    }
--- a/src/core/build/builder/artifact.rs
+++ b/src/core/build/builder/artifact.rs
@@ -0,0 +1,126 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
+use crate::platform;
+use crate::utils::build::is_bare_metal_target;
+use std::process::Command;
+use std::time::Instant;
+
+pub(crate) fn archive_static(
+    ctx: &BuildContext,
+    objects: &[String],
+    start_time: Instant,
+) -> Result<f64, String> {
+    let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
+    if !common::needs_link(objects, &lib_path) {
+        return Ok(common::elapsed_secs(start_time));
+    }
+
+    let archiver = ctx.archiver.unwrap_or(if cfg!(target_os = "windows") {
+        "lib"
+    } else {
+        "ar"
+    });
+
+    let mut cmd = Command::new(archiver);
+    if cfg!(target_os = "windows") && archiver == "lib" {
+        cmd.arg("/nologo").arg(format!("/OUT:{lib_path}"));
+    } else {
+        cmd.arg("rcs").arg(&lib_path);
+    }
+    for obj in objects {
+        cmd.arg(obj);
+    }
+    run(ctx, cmd, start_time)
+}
+
+pub(crate) fn link_binary(
+    ctx: &BuildContext,
+    objects: &[String],
+    default_linker: &str,
+    start_time: Instant,
+) -> Result<f64, String> {
+    let mut cmd = Command::new(ctx.linker.unwrap_or(default_linker));
+    if ctx.kind == "sharedlib" {
+        if cfg!(target_os = "macos") {
+            cmd.arg("-dynamiclib");
+        } else {
+            cmd.arg("-shared");
+        }
+    }
+    if ctx.kind == "efi" {
+        cmd.arg("-shared");
+        cmd.arg("-nostdlib");
+        cmd.arg("-Wl,-dll");
+        cmd.arg("-Wl,--subsystem,10");
+    } else if ctx.freestanding || is_bare_metal_target(ctx.target) {
+        cmd.arg("-nostdlib");
+        cmd.arg("-static");
+    }
+    for obj in objects {
+        cmd.arg(obj);
+    }
+    for dir in ctx.lib_dirs {
+        cmd.arg(format!("-L{dir}"));
+    }
+    for lib in ctx.libs {
+        cmd.arg(format!("-l{lib}"));
+    }
+    for flag in ctx.ldflags {
+        cmd.arg(flag);
+    }
+
+    let name = ctx.output_filename.unwrap_or(ctx.project_name);
+    let ext = ctx.output_extension.unwrap_or("");
+    let final_name = if ext.is_empty() {
+        name.to_string()
+    } else {
+        format!("{}.{}", name, ext)
+    };
+
+    let out_path = if ctx.kind == "sharedlib" {
+        platform::shared_lib_path(ctx.profile, &final_name, ctx.target_dir)
+    } else if ctx.kind == "efi" {
+        platform::efi_path(ctx.profile, &final_name, ctx.target_dir)
+    } else if ctx.kind == "elf" {
+        platform::elf_path(ctx.profile, &final_name, ctx.target_dir)
+    } else {
+        platform::bin_path(ctx.profile, &final_name, ctx.target_dir)
+    };
+
+    if !common::needs_link(objects, &out_path) {
+        return Ok(common::elapsed_secs(start_time));
+    }
+    cmd.arg("-o").arg(out_path);
+    run(ctx, cmd, start_time)
+}
+
+fn run(ctx: &BuildContext, mut cmd: Command, start_time: Instant) -> Result<f64, String> {
+    if ctx.verbose || std::env::var("DCR_DEBUG").is_ok() {
+        eprintln!("[dcr] {:?}", cmd);
+    }
+    let output = cmd.output().map_err(|err| format!("Build failed: {err}"))?;
+    if output.status.success() {
+        Ok(common::elapsed_secs(start_time))
+    } else {
+        let stderr = String::from_utf8_lossy(&output.stderr);
+        let stdout = String::from_utf8_lossy(&output.stdout);
+        Err(format!("Build failed:\nstdout: {stdout}\nstderr: {stderr}"))
+    }
+}
--- a/src/core/build/builder/cc_common.rs
+++ b/src/core/build/builder/cc_common.rs
@@ -15,9 +15,9 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

-use crate::core::builder::BuildContext;
-use crate::core::builder::common;
-use crate::platform;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::builder::artifact;
+use crate::core::build::common;
 use crate::utils::build::is_bare_metal_target;
 use std::fs;
 use std::path::{Path, PathBuf};
@@ -36,7 +36,7 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
        None => Path::new("./target").join(ctx.profile).join("obj"),
    };
    let qt_include_path = if ctx.qt {
-        crate::core::builder::qt::process_qt(ctx, &obj_dir)?
+        crate::core::build::language::cxx::qt::process_qt(ctx, &obj_dir)?
    } else {
        None
    };
@@ -56,93 +56,10 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
    let objects = build_objects(compiler, &sources, &obj_dir, ctx, "o", qt_include_path)?;

    if ctx.kind == "staticlib" {
-        let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
-        if !common::needs_link(&objects, &lib_path) {
-            let elapsed = common::elapsed_secs(start_time);
-            return Ok(elapsed);
-        }
-        let mut cmd = Command::new(ctx.archiver.unwrap_or("ar"));
-        cmd.arg("rcs").arg(&lib_path);
-        for obj in &objects {
-            cmd.arg(obj);
-        }
-        if ctx.verbose || std::env::var("DCR_DEBUG").is_ok() {
-            eprintln!("[dcr] {:?}", cmd);
-        }
-        match cmd.status() {
-            Ok(status) if status.success() => {
-                let elapsed = common::elapsed_secs(start_time);
-                return Ok(elapsed);
-            }
-            Ok(_) => return Err("Build failed".to_string()),
-            Err(err) => return Err(format!("Build failed: {err}")),
-        }
+        return artifact::archive_static(ctx, &objects, start_time);
    }

-    let mut cmd = Command::new(ctx.linker.unwrap_or(compiler));
-    if ctx.kind == "sharedlib" {
-        if cfg!(target_os = "macos") {
-            cmd.arg("-dynamiclib");
-        } else {
-            cmd.arg("-shared");
-        }
-    }
-    if ctx.kind == "efi" {
-        cmd.arg("-shared");
-        cmd.arg("-nostdlib");
-        cmd.arg("-Wl,-dll");
-        cmd.arg("-Wl,--subsystem,10");
-    } else if ctx.freestanding || is_bare_metal_target(ctx.target) {
-        cmd.arg("-nostdlib");
-        cmd.arg("-static");
-    }
-    for obj in &objects {
-        cmd.arg(obj);
-    }
-    for dir in ctx.lib_dirs {
-        cmd.arg(format!("-L{dir}"));
-    }
-    for lib in ctx.libs {
-        cmd.arg(format!("-l{lib}"));
-    }
-    for flag in ctx.ldflags {
-        cmd.arg(flag);
-    }
-    let name = ctx.output_filename.unwrap_or(ctx.project_name);
-    let ext = ctx.output_extension.unwrap_or("");
-    let final_name = if ext.is_empty() {
-        name.to_string()
-    } else {
-        format!("{}.{}", name, ext)
-    };
-
-    let out_path = if ctx.kind == "sharedlib" {
-        platform::shared_lib_path(ctx.profile, &final_name, ctx.target_dir)
-    } else if ctx.kind == "efi" {
-        platform::efi_path(ctx.profile, &final_name, ctx.target_dir)
-    } else if ctx.kind == "elf" {
-        platform::elf_path(ctx.profile, &final_name, ctx.target_dir)
-    } else {
-        platform::bin_path(ctx.profile, &final_name, ctx.target_dir)
-    };
-
-    if !common::needs_link(&objects, &out_path) {
-        let elapsed = common::elapsed_secs(start_time);
-        return Ok(elapsed);
-    }
-    cmd.arg("-o").arg(out_path);
-
-    if ctx.verbose || std::env::var("DCR_DEBUG").is_ok() {
-        eprintln!("[dcr] {:?}", cmd);
-    }
-    match cmd.status() {
-        Ok(status) if status.success() => {
-            let elapsed = common::elapsed_secs(start_time);
-            Ok(elapsed)
-        }
-        Ok(_) => Err("Build failed".to_string()),
-        Err(err) => Err(format!("Build failed: {err}")),
-    }
+    artifact::link_binary(ctx, &objects, compiler, start_time)
 }

 pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
@@ -156,7 +73,7 @@ pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String>
 }

 fn source_extensions(language: &str) -> Vec<&'static str> {
-    crate::core::builder::common::source_extensions(language)
+    crate::core::build::common::source_extensions(language)
 }

 fn default_flags(profile: &str) -> &'static [&'static str] {
@@ -288,5 +205,5 @@ fn build_object(
 }

 fn asm_lang_flag(source: &str) -> Option<&'static str> {
-    crate::core::builder::common::asm_lang_flag(source)
+    crate::core::build::common::asm_lang_flag(source)
 }
--- a/src/core/build/builder/mod.rs
+++ b/src/core/build/builder/mod.rs
@@ -0,0 +1,234 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub mod artifact;
+pub mod cc_common;
+pub mod msvc;
+
+use crate::core::build::language::asm::{fasm, gas, masm, nasm};
+use crate::core::build::language::llvm_ir;
+
+pub struct BuildContext<'a> {
+    pub profile: &'a str,
+    pub project_name: &'a str,
+    pub compiler: &'a str,
+    pub language: &'a str,
+    pub standard: &'a str,
+    pub cxx_standard: &'a str,
+    pub target: Option<&'a str>,
+    pub target_dir: Option<&'a str>,
+    pub kind: &'a str,
+    pub platform: Option<&'a str>,
+    pub linker: Option<&'a str>,
+    pub archiver: Option<&'a str>,
+    pub moc: Option<&'a str>,
+    pub uic: Option<&'a str>,
+    pub rcc: Option<&'a str>,
+    pub package_type: Option<&'a str>,
+    pub freestanding: bool,
+    pub panic_abort: bool,
+    pub codegen_units: usize,
+    pub source_roots: &'a [std::path::PathBuf],
+    pub exclude_dirs: &'a [std::path::PathBuf],
+    pub include_paths: &'a [String],
+    pub include_dirs: &'a [String],
+    pub lib_dirs: &'a [String],
+    pub libs: &'a [String],
+    pub cflags: &'a [String],
+    pub ldflags: &'a [String],
+    pub output_filename: Option<&'a str>,
+    pub output_extension: Option<&'a str>,
+    pub verbose: bool,
+    pub qt: bool,
+}
+
+pub trait Builder {
+    #[allow(dead_code)]
+    fn id(&self) -> &'static str;
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String>;
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String>;
+}
+
+struct Cc;
+struct Msvc;
+struct Nasm;
+struct Gas;
+struct Masm;
+struct Fasm;
+struct Llc;
+
+impl Builder for Cc {
+    fn id(&self) -> &'static str {
+        "cc"
+    }
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String> {
+        cc_common::build(ctx)
+    }
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String> {
+        cc_common::collect_sources(ctx)
+    }
+}
+
+impl Builder for Msvc {
+    fn id(&self) -> &'static str {
+        "msvc"
+    }
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String> {
+        msvc::build(ctx)
+    }
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String> {
+        msvc::collect_sources(ctx)
+    }
+}
+
+impl Builder for Nasm {
+    fn id(&self) -> &'static str {
+        "nasm"
+    }
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String> {
+        nasm::build(ctx)
+    }
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String> {
+        nasm::collect_sources(ctx)
+    }
+}
+
+impl Builder for Gas {
+    fn id(&self) -> &'static str {
+        "gas"
+    }
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String> {
+        gas::build(ctx)
+    }
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String> {
+        gas::collect_sources(ctx)
+    }
+}
+
+impl Builder for Masm {
+    fn id(&self) -> &'static str {
+        "masm"
+    }
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String> {
+        masm::build(ctx)
+    }
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String> {
+        masm::collect_sources(ctx)
+    }
+}
+
+impl Builder for Fasm {
+    fn id(&self) -> &'static str {
+        "fasm"
+    }
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String> {
+        fasm::build(ctx)
+    }
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String> {
+        fasm::collect_sources(ctx)
+    }
+}
+
+impl Builder for Llc {
+    fn id(&self) -> &'static str {
+        "llvm_ir"
+    }
+    fn build(&self, ctx: &BuildContext) -> Result<f64, String> {
+        llvm_ir::build(ctx)
+    }
+    fn collect_sources(&self, ctx: &BuildContext) -> Result<Vec<String>, String> {
+        llvm_ir::collect_sources(ctx)
+    }
+}
+
+pub fn builder_for(compiler: &str) -> &'static dyn Builder {
+    let c = compiler.to_lowercase();
+    if c.contains("clang-cl") {
+        return &Msvc;
+    }
+    if c == "as" || c.contains("gas") {
+        return &Gas;
+    }
+    if c.contains("llc") {
+        return &Llc;
+    }
+    if c.contains("fasm") {
+        return &Fasm;
+    }
+    if c.contains("nasm") {
+        return &Nasm;
+    }
+    if c == "ml" || c == "ml64" || c.contains("masm") {
+        return &Masm;
+    }
+    if c == "cl" || c.contains("msvc") {
+        return &Msvc;
+    }
+    &Cc
+}
+
+pub fn build(ctx: &BuildContext) -> Result<f64, String> {
+    if !check_compiler_exists(ctx.compiler) {
+        return Err(format!(
+            "Compiler not found: {}. Make sure it is installed and available in PATH.",
+            ctx.compiler
+        ));
+    }
+    builder_for(ctx.compiler).build(ctx)
+}
+
+fn check_compiler_exists(compiler: &str) -> bool {
+    let name = if compiler.is_empty() {
+        "cc"
+    } else {
+        match compiler.to_lowercase().as_str() {
+            "gas" | "gnu-as" => "as",
+            "nasm" => "nasm",
+            "fasm" | "fasm64" => "fasm",
+            "masm" | "ml" | "ml64" => "ml",
+            _ => compiler,
+        }
+    };
+    std::process::Command::new(name)
+        .arg("--version")
+        .output()
+        .is_ok()
+}
+
+pub fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
+    builder_for(ctx.compiler).collect_sources(ctx)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn builder_resolves_by_compiler_name() {
+        assert_eq!(builder_for("gcc").id(), "cc");
+        assert_eq!(builder_for("clang").id(), "cc");
+        assert_eq!(builder_for("clang++").id(), "cc");
+        assert_eq!(builder_for("").id(), "cc");
+        assert_eq!(builder_for("nasm").id(), "nasm");
+        assert_eq!(builder_for("as").id(), "gas");
+        assert_eq!(builder_for("llc-18").id(), "llvm_ir");
+        assert_eq!(builder_for("fasm").id(), "fasm");
+        assert_eq!(builder_for("ml64").id(), "masm");
+        assert_eq!(builder_for("cl").id(), "msvc");
+        assert_eq!(builder_for("clang-cl").id(), "msvc");
+    }
+}
--- a/src/core/build/builder/msvc/mod.rs
+++ b/src/core/build/builder/msvc/mod.rs
@@ -15,8 +15,8 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

-use crate::core::builder::BuildContext;
-use crate::core::builder::common;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
 use crate::platform;
 use std::fs;
 use std::path::Path;
@@ -152,7 +152,7 @@ pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String>
 }

 fn source_extensions(language: &str) -> Vec<&'static str> {
-    crate::core::builder::common::source_extensions(language)
+    crate::core::build::common::source_extensions(language)
 }

 fn msvc_standard_flag(language: &str, standard: &str) -> Result<String, String> {
--- a/src/core/build/cache.rs
+++ b/src/core/build/cache.rs
@@ -0,0 +1,254 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
+use sha2::{Digest, Sha256};
+use std::fs;
+use std::path::{Path, PathBuf};
+
+pub(crate) fn compute_build_fingerprint(
+    ctx: &BuildContext,
+    sources: &[String],
+    headers: &[PathBuf],
+    lib_files: &[PathBuf],
+) -> Result<String, String> {
+    let mut hasher = Sha256::new();
+    hasher.update(ctx.profile.as_bytes());
+    hasher.update(ctx.project_name.as_bytes());
+    hasher.update(ctx.compiler.as_bytes());
+    hasher.update(ctx.language.as_bytes());
+    hasher.update(ctx.standard.as_bytes());
+    hasher.update(ctx.kind.as_bytes());
+    if let Some(v) = ctx.target_dir {
+        hasher.update(v.as_bytes());
+    }
+    if let Some(v) = ctx.platform {
+        hasher.update(v.as_bytes());
+    }
+    if let Some(v) = ctx.linker {
+        hasher.update(v.as_bytes());
+    }
+    if let Some(v) = ctx.archiver {
+        hasher.update(v.as_bytes());
+    }
+    for value in ctx.include_dirs {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.lib_dirs {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.libs {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.cflags {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.ldflags {
+        hasher.update(value.as_bytes());
+    }
+    let toml =
+        fs::read_to_string("dcr.toml").map_err(|err| format!("Failed to read dcr.toml: {err}"))?;
+    hasher.update(toml.as_bytes());
+    if let Ok(lock) = fs::read_to_string("dcr.lock") {
+        hasher.update(lock.as_bytes());
+    }
+    for source in sources {
+        let path = Path::new(source);
+        update_hasher_with_file(&mut hasher, path)?;
+    }
+    for header in headers {
+        update_hasher_with_file(&mut hasher, header)?;
+    }
+    for lib in lib_files {
+        update_hasher_with_file(&mut hasher, lib)?;
+    }
+    Ok(to_hex(&hasher.finalize()))
+}
+
+pub(crate) fn should_skip_build(ctx: &BuildContext, fingerprint: &str) -> bool {
+    let output = build_output_path(ctx);
+    if !Path::new(&output).is_file() {
+        return false;
+    }
+    let cache_path = build_cache_path(ctx.profile, ctx.target_dir);
+    let cached = fs::read_to_string(cache_path).unwrap_or_default();
+    cached.trim() == fingerprint
+}
+
+pub(crate) fn write_build_fingerprint(ctx: &BuildContext, fingerprint: &str) -> Result<(), String> {
+    let cache_path = build_cache_path(ctx.profile, ctx.target_dir);
+    if let Some(parent) = cache_path.parent() {
+        fs::create_dir_all(parent).map_err(|err| format!("Failed to create cache dir: {err}"))?;
+    }
+    fs::write(cache_path, format!("{fingerprint}\n"))
+        .map_err(|err| format!("Failed to write cache: {err}"))
+}
+
+fn build_cache_path(profile: &str, target_dir: Option<&str>) -> PathBuf {
+    match target_dir {
+        Some(dir) => Path::new(dir).join(".dcr-build.hash"),
+        None => Path::new("./target").join(profile).join(".dcr-build.hash"),
+    }
+}
+
+fn build_output_path(ctx: &BuildContext) -> String {
+    let name = ctx.output_filename.unwrap_or(ctx.project_name);
+    let ext = ctx.output_extension.unwrap_or("");
+
+    let final_name = if ext.is_empty() {
+        name.to_string()
+    } else {
+        format!("{}.{}", name, ext)
+    };
+
+    if ctx.kind == "staticlib" {
+        return crate::platform::lib_path(ctx.profile, &final_name, ctx.target_dir);
+    }
+    if ctx.kind == "sharedlib" {
+        return crate::platform::shared_lib_path(ctx.profile, &final_name, ctx.target_dir);
+    }
+    if ctx.kind == "efi" {
+        return crate::platform::efi_path(ctx.profile, &final_name, ctx.target_dir);
+    }
+    if ctx.kind == "elf" {
+        return crate::platform::elf_path(ctx.profile, &final_name, ctx.target_dir);
+    }
+    crate::platform::bin_path(ctx.profile, &final_name, ctx.target_dir)
+}
+
+pub(crate) fn collect_header_files(
+    ctx: &BuildContext,
+    project_root: &Path,
+) -> Result<Vec<PathBuf>, String> {
+    let mut out = Vec::new();
+    let mut roots = Vec::new();
+    if ctx.source_roots.is_empty() {
+        roots.push(project_root.join("src"));
+    } else {
+        roots.extend(ctx.source_roots.iter().cloned());
+    }
+    let abs_root = project_root
+        .canonicalize()
+        .unwrap_or_else(|_| project_root.to_path_buf());
+    for dir in ctx.include_dirs {
+        let p = Path::new(dir).to_path_buf();
+        if let Ok(abs_p) = p.canonicalize() {
+            if abs_p.starts_with(&abs_root) {
+                roots.push(abs_p);
+            }
+        } else if p.starts_with(&abs_root) {
+            roots.push(p);
+        }
+    }
+    for root in roots {
+        if !root.exists() {
+            continue;
+        }
+        collect_header_files_rec(&root, &mut out, ctx.exclude_dirs, ctx.include_paths)?;
+    }
+    out.sort();
+    out.dedup();
+    Ok(out)
+}
+
+fn collect_header_files_rec(
+    dir: &Path,
+    out: &mut Vec<PathBuf>,
+    exclude_dirs: &[PathBuf],
+    include_paths: &[String],
+) -> Result<(), String> {
+    if common::is_excluded(dir, exclude_dirs, include_paths) && include_paths.is_empty() {
+        return Ok(());
+    }
+    for entry in fs::read_dir(dir).map_err(|err| format!("read_dir error: {err}"))? {
+        let entry = entry.map_err(|err| format!("read_dir error: {err}"))?;
+        let path = entry.path();
+        if path.is_dir() {
+            if common::is_excluded(&path, exclude_dirs, include_paths) && include_paths.is_empty() {
+                continue;
+            }
+            collect_header_files_rec(&path, out, exclude_dirs, include_paths)?;
+            continue;
+        }
+        if !path.is_file() {
+            continue;
+        }
+        if common::is_excluded(&path, exclude_dirs, include_paths) {
+            continue;
+        }
+        if is_header_file(&path) {
+            out.push(path);
+        }
+    }
+    Ok(())
+}
+
+fn is_header_file(path: &Path) -> bool {
+    let ext = path.extension().and_then(|v| v.to_str()).unwrap_or("");
+    matches!(ext, "h" | "hpp" | "hh" | "hxx" | "inc")
+}
+
+pub(crate) fn collect_lib_files(ctx: &BuildContext) -> Vec<PathBuf> {
+    let mut out = Vec::new();
+    for dir in ctx.lib_dirs {
+        let dir_path = Path::new(dir);
+        for lib in ctx.libs {
+            for candidate in lib_candidates(lib) {
+                let path = dir_path.join(candidate);
+                if path.is_file() {
+                    out.push(path);
+                }
+            }
+        }
+    }
+    out
+}
+
+fn lib_candidates(name: &str) -> Vec<String> {
+    if cfg!(target_os = "windows") {
+        return vec![format!("{name}.lib")];
+    }
+    if cfg!(target_os = "macos") {
+        return vec![
+            format!("lib{name}.a"),
+            format!("lib{name}.dylib"),
+            format!("lib{name}.so"),
+        ];
+    }
+    vec![
+        format!("lib{name}.a"),
+        format!("lib{name}.so"),
+        format!("lib{name}.so.0"),
+    ]
+}
+
+fn update_hasher_with_file(hasher: &mut Sha256, path: &Path) -> Result<(), String> {
+    hasher.update(path.to_string_lossy().as_bytes());
+    let meta = fs::metadata(path).map_err(|err| format!("source read error: {err}"))?;
+    hasher.update(meta.len().to_le_bytes());
+    if let Ok(modified) = meta.modified()
+        && let Ok(duration) = modified.duration_since(std::time::UNIX_EPOCH)
+    {
+        hasher.update(duration.as_nanos().to_le_bytes());
+    }
+    Ok(())
+}
+
+fn to_hex(bytes: &[u8]) -> String {
+    crate::utils::fs::to_hex(bytes)
+}
--- a/src/core/builder/common.rs
+++ b/src/core/builder/common.rs
@@ -58,9 +58,10 @@ fn collect_sources_rec(
    if is_excluded(&full_dir, exclude_dirs, include_paths) && include_paths.is_empty() {
        return Ok(());
    }
-    let entries = fs::read_dir(&full_dir).map_err(|err| format!("src dir error: {err}"))?;
+    let entries = fs::read_dir(&full_dir)
+        .map_err(|err| format!("src dir error for {:?}: {err}", full_dir))?;
    for entry in entries {
-        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
+        let entry = entry.map_err(|err| format!("src dir error for {:?}: {err}", full_dir))?;
        let path = entry.path();
        if path.is_dir() {
            if is_excluded(&path, exclude_dirs, include_paths) && include_paths.is_empty() {
@@ -177,12 +178,8 @@ pub fn asm_lang_flag(source: &str) -> Option<&'static str> {
 pub fn source_extensions(language: &str) -> Vec<&'static str> {
    let mut out = Vec::new();
    for part in language.split(',').map(|s| s.trim()) {
-        let lang = part.to_lowercase();
-        match lang.as_str() {
-            "c" => out.extend(["c"]),
-            "c++" | "cpp" | "cxx" => out.extend(["cpp", "cxx", "cc"]),
-            "asm" => out.extend(["s", "S", "asm"]),
-            _ => {}
+        if let Some(lang) = crate::core::build::language::language_for_token(part) {
+            out.extend(lang.extensions().iter().copied());
        }
    }
    if out.is_empty() {
@@ -331,7 +328,7 @@ pub fn needs_rebuild(source: &str, object: &str) -> bool {
                    return true;
                }
            } else {
-                return true; // Missing dependency triggers rebuild
+                return true;
            }
        }
    }
@@ -537,7 +534,6 @@ mod tests {
        let src = dir.join("test.c");
        let obj = dir.join("test.o");
        fs::write(&src, "int main() {}").unwrap();
-        // Sleep briefly to ensure mtime difference
        std::thread::sleep(std::time::Duration::from_millis(50));
        fs::write(&obj, "").unwrap();
        assert!(!needs_rebuild(
--- a/src/core/build/engine.rs
+++ b/src/core/build/engine.rs
--- a/src/core/build/language/asm/common.rs
+++ b/src/core/build/language/asm/common.rs
@@ -0,0 +1,83 @@
+use crate::core::build::builder::BuildContext;
+use crate::core::build::builder::artifact;
+use crate::core::build::common;
+use std::path::Path;
+use std::time::Instant;
+
+pub fn filter_asm_flags(flags: &[String]) -> Vec<String> {
+    flags
+        .iter()
+        .filter(|f| {
+            let f = f.as_str();
+            f.starts_with("-I") || f.starts_with("-i") || f == "-g"
+        })
+        .cloned()
+        .collect()
+}
+
+pub fn build_assembly<F>(
+    ctx: &BuildContext,
+    backend_name: &str,
+    default_assembler: &str,
+    extensions: &[&str],
+    build_object: F,
+) -> Result<f64, String>
+where
+    F: Fn(&str, &str, &str, &BuildContext) -> Result<(), String> + Sync,
+{
+    let lang = ctx.language.to_lowercase();
+    if lang.split(',').any(|p| p.trim() != "asm") {
+        return Err(format!(
+            "{backend_name} backend requires build.language = \"asm\""
+        ));
+    }
+
+    let assembler = if ctx.compiler.is_empty() {
+        default_assembler
+    } else {
+        ctx.compiler
+    };
+
+    let start_time = Instant::now();
+    let sources = common::collect_sources(
+        ctx.source_roots,
+        extensions,
+        ctx.exclude_dirs,
+        ctx.include_paths,
+    )?;
+    let obj_dir = match ctx.target_dir {
+        Some(dir) => Path::new(dir).join("obj"),
+        None => Path::new("./target").join(ctx.profile).join("obj"),
+    };
+    let objects = build_objects_common(assembler, &sources, &obj_dir, ctx, &build_object)?;
+
+    if ctx.kind == "staticlib" {
+        return artifact::archive_static(ctx, &objects, start_time);
+    }
+
+    artifact::link_binary(ctx, &objects, "cc", start_time)
+}
+
+fn build_objects_common<F>(
+    assembler: &str,
+    sources: &[String],
+    obj_dir: &Path,
+    ctx: &BuildContext,
+    build_object: &F,
+) -> Result<Vec<String>, String>
+where
+    F: Fn(&str, &str, &str, &BuildContext) -> Result<(), String> + Sync,
+{
+    let objects: Vec<String> = sources
+        .iter()
+        .map(|s| common::object_path(obj_dir, s, "o"))
+        .collect();
+
+    common::parallel_build(
+        sources.len(),
+        |i| build_object(assembler, &sources[i], &objects[i], ctx),
+        ctx.codegen_units,
+    )?;
+
+    Ok(objects)
+}
--- a/src/core/build/language/asm/fasm/mod.rs
+++ b/src/core/build/language/asm/fasm/mod.rs
@@ -1,6 +1,6 @@
-use crate::core::builder::BuildContext;
-use crate::core::builder::asm;
-use crate::core::builder::common;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
+use crate::core::build::language::asm::common as asm;
 use std::fs;
 use std::path::Path;
 use std::process::Command;
@@ -35,7 +35,7 @@ fn build_object(
    let mut cmd = Command::new(assembler);
    cmd.arg(source).arg(obj_path);

-    for flag in ctx.cflags {
+    for flag in crate::core::build::language::asm::common::filter_asm_flags(ctx.cflags) {
        cmd.arg(flag);
    }

--- a/src/core/build/language/asm/gas/mod.rs
+++ b/src/core/build/language/asm/gas/mod.rs
@@ -15,15 +15,24 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

-use crate::core::builder::BuildContext;
-use crate::core::builder::asm;
-use crate::core::builder::common;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
+use crate::core::build::language::asm::common as asm;
 use std::fs;
 use std::path::Path;
 use std::process::Command;

 pub fn build(ctx: &BuildContext) -> Result<f64, String> {
-    asm::build_assembly(ctx, "GAS", "as", &["s"], build_object)
+    // Use full path to as
+    let as_path = std::process::Command::new("which")
+        .arg("as")
+        .output()
+        .ok()
+        .and_then(|o| String::from_utf8(o.stdout).ok())
+        .map(|s| s.trim().to_string())
+        .filter(|s| !s.is_empty())
+        .unwrap_or_else(|| "as".to_string());
+    asm::build_assembly(ctx, "GAS", &as_path, &["s"], build_object)
 }

 pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
@@ -52,9 +61,13 @@ fn build_object(
    let mut cmd = Command::new(assembler);
    cmd.arg(source).arg("-o").arg(obj_path);

-    for flag in ctx.cflags {
+    for flag in crate::core::build::language::asm::common::filter_asm_flags(ctx.cflags) {
        cmd.arg(flag);
    }

+    if ctx.verbose || std::env::var("DCR_DEBUG").is_ok() {
+        eprintln!("[dcr] {:?}", cmd);
+    }
+
    common::run_command_sync_output(&mut cmd)
 }
--- a/src/core/build/language/asm/masm/mod.rs
+++ b/src/core/build/language/asm/masm/mod.rs
@@ -1,6 +1,6 @@
-use crate::core::builder::BuildContext;
-use crate::core::builder::asm;
-use crate::core::builder::common;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
+use crate::core::build::language::asm::common as asm;
 use std::fs;
 use std::path::Path;
 use std::process::Command;
@@ -39,7 +39,7 @@ fn build_object(
        .arg(obj_path)
        .arg(source);

-    for flag in ctx.cflags {
+    for flag in crate::core::build::language::asm::common::filter_asm_flags(ctx.cflags) {
        cmd.arg(flag);
    }

--- a/src/core/build/language/asm/mod.rs
+++ b/src/core/build/language/asm/mod.rs
@@ -0,0 +1,38 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub mod common;
+pub mod fasm;
+pub mod gas;
+pub mod masm;
+pub mod nasm;
+
+use crate::core::build::language::Language;
+
+pub struct Asm;
+
+impl Language for Asm {
+    fn id(&self) -> &'static str {
+        "asm"
+    }
+    fn extensions(&self) -> &'static [&'static str] {
+        &["s", "S", "asm"]
+    }
+    fn matches_token(&self, token: &str) -> bool {
+        token.eq_ignore_ascii_case("asm")
+    }
+}
--- a/src/core/build/language/asm/nasm/mod.rs
+++ b/src/core/build/language/asm/nasm/mod.rs
@@ -15,22 +15,22 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

-use crate::core::builder::BuildContext;
-use crate::core::builder::asm;
-use crate::core::builder::common;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
+use crate::core::build::language::asm::common as asm;
 use std::fs;
 use std::path::Path;
 use std::process::Command;

 pub fn build(ctx: &BuildContext) -> Result<f64, String> {
-    asm::build_assembly(ctx, "NASM", "nasm", &["asm", "s"], build_object)
+    asm::build_assembly(ctx, "NASM", "nasm", &["asm"], build_object)
 }

 pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
-    // NASM handles lowercase .s and .asm only (not .S which is GCC preprocessed)
+    // NASM handles .asm only (not .s which is GAS syntax, not .S which is GCC preprocessed)
    common::collect_sources(
        ctx.source_roots,
-        &["asm", "s"],
+        &["asm"],
        ctx.exclude_dirs,
        ctx.include_paths,
    )
@@ -59,7 +59,7 @@ fn build_object(
        .arg("-o")
        .arg(obj_path);

-    for flag in ctx.cflags {
+    for flag in crate::core::build::language::asm::common::filter_asm_flags(ctx.cflags) {
        cmd.arg(flag);
    }

--- a/src/core/build/language/c/mod.rs
+++ b/src/core/build/language/c/mod.rs
@@ -0,0 +1,32 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use crate::core::build::language::Language;
+
+pub struct C;
+
+impl Language for C {
+    fn id(&self) -> &'static str {
+        "c"
+    }
+    fn extensions(&self) -> &'static [&'static str] {
+        &["c"]
+    }
+    fn matches_token(&self, token: &str) -> bool {
+        token.eq_ignore_ascii_case("c")
+    }
+}
--- a/src/core/build/language/cxx/mod.rs
+++ b/src/core/build/language/cxx/mod.rs
@@ -0,0 +1,34 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub mod qt;
+
+use crate::core::build::language::Language;
+
+pub struct Cxx;
+
+impl Language for Cxx {
+    fn id(&self) -> &'static str {
+        "cxx"
+    }
+    fn extensions(&self) -> &'static [&'static str] {
+        &["cpp", "cxx", "cc"]
+    }
+    fn matches_token(&self, token: &str) -> bool {
+        matches!(token.to_lowercase().as_str(), "c++" | "cpp" | "cxx")
+    }
+}
--- a/src/core/build/language/cxx/qt.rs
+++ b/src/core/build/language/cxx/qt.rs
@@ -15,8 +15,8 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

-use crate::core::builder::BuildContext;
-use crate::core::builder::common;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
 use crate::utils::build::run_pkg_config;
 use std::fs;
 use std::path::{Path, PathBuf};
@@ -34,14 +34,12 @@ pub fn process_qt(ctx: &BuildContext, build_dir: &Path) -> Result<Option<PathBuf
        ctx.include_paths,
    )?;

-    // Fetch Qt system include paths and defines for MOC
    let mut qt_moc_args = Vec::new();
    let qt_modules = vec!["Qt6Core", "Qt6Widgets", "Qt6Gui", "Qt6Svg"];

    for module in qt_modules {
        if let Ok(cflags) = run_pkg_config(module, "--cflags") {
            for flag in cflags.split_whitespace() {
-                // Pass both -I and -D flags to moc
                if flag.starts_with("-I") || flag.starts_with("-D") {
                    qt_moc_args.push(flag.to_string());
                }
@@ -96,12 +94,10 @@ pub fn process_qt(ctx: &BuildContext, build_dir: &Path) -> Result<Option<PathBuf

                        let mut moc_args = Vec::new();

-                        // Add Qt system cflags (includes + defines)
                        for arg in &qt_moc_args {
                            moc_args.push(arg.as_str());
                        }

-                        // Add project include paths
                        for inc in ctx.include_paths.iter().chain(ctx.include_dirs.iter()) {
                            moc_args.push("-I");
                            moc_args.push(inc);
--- a/src/core/build/language/llvm_ir/mod.rs
+++ b/src/core/build/language/llvm_ir/mod.rs
@@ -1,10 +1,25 @@
-use crate::core::builder::BuildContext;
-use crate::core::builder::asm;
-use crate::core::builder::common;
+use crate::core::build::builder::BuildContext;
+use crate::core::build::common;
+use crate::core::build::language::Language;
+use crate::core::build::language::asm::common as asm;
 use std::fs;
 use std::path::Path;
 use std::process::Command;

+pub struct LlvmIr;
+
+impl Language for LlvmIr {
+    fn id(&self) -> &'static str {
+        "llvm_ir"
+    }
+    fn extensions(&self) -> &'static [&'static str] {
+        &["ll"]
+    }
+    fn matches_token(&self, token: &str) -> bool {
+        matches!(token.to_lowercase().as_str(), "llvm_ir" | "llvm-ir" | "ll")
+    }
+}
+
 pub fn build(ctx: &BuildContext) -> Result<f64, String> {
    asm::build_assembly(ctx, "LLVM-IR", "llc", &["ll"], build_object)
 }
--- a/src/core/build/language/mod.rs
+++ b/src/core/build/language/mod.rs
@@ -0,0 +1,57 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub mod asm;
+pub mod c;
+pub mod cxx;
+pub mod llvm_ir;
+
+pub trait Language {
+    fn id(&self) -> &'static str;
+    fn extensions(&self) -> &'static [&'static str];
+    fn matches_token(&self, token: &str) -> bool;
+}
+
+pub fn languages() -> [&'static dyn Language; 4] {
+    [&c::C, &cxx::Cxx, &asm::Asm, &llvm_ir::LlvmIr]
+}
+
+pub fn language_for_token(token: &str) -> Option<&'static dyn Language> {
+    languages().into_iter().find(|l| l.matches_token(token))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn tokens_resolve_to_languages() {
+        assert_eq!(language_for_token("c").unwrap().id(), "c");
+        assert_eq!(language_for_token("c++").unwrap().id(), "cxx");
+        assert_eq!(language_for_token("cpp").unwrap().id(), "cxx");
+        assert_eq!(language_for_token("cxx").unwrap().id(), "cxx");
+        assert_eq!(language_for_token("asm").unwrap().id(), "asm");
+        assert!(language_for_token("rust").is_none());
+    }
+
+    #[test]
+    fn languages_expose_expected_extensions() {
+        assert_eq!(c::C.extensions(), &["c"]);
+        assert_eq!(cxx::Cxx.extensions(), &["cpp", "cxx", "cc"]);
+        assert_eq!(asm::Asm.extensions(), &["s", "S", "asm"]);
+    }
+}
--- a/src/core/build/mod.rs
+++ b/src/core/build/mod.rs
@@ -0,0 +1,29 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub mod builder;
+pub mod cache;
+pub mod common;
+pub mod engine;
+pub mod language;
+pub mod report;
+pub mod resolve;
+pub mod steps;
+
+pub use engine::run_build;
+pub use report::{BuildEvent, BuildReporter, BuildRequest};
+pub use resolve::get_build_string_with_profile;
--- a/src/core/build/report.rs
+++ b/src/core/build/report.rs
@@ -0,0 +1,83 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// The reporter decouples the build engine from any particular frontend: the CLI
+// renders events as coloured lines, a TUI/GUI would push them into a widget and
+// MCP would serialise them to JSON. The engine only ever calls `on_event`.
+
+use std::sync::{Arc, atomic::AtomicBool};
+
+pub struct BuildRequest {
+    pub profile: String,
+    pub target: Option<String>,
+    pub force: bool,
+    pub verbose: bool,
+    pub workspace: Option<String>,
+    pub cancel: Arc<AtomicBool>,
+}
+
+#[allow(dead_code)]
+pub struct BuildOutcome {
+    pub secs: f64,
+}
+
+pub struct BuildError {
+    pub message: String,
+}
+
+impl From<String> for BuildError {
+    fn from(message: String) -> Self {
+        BuildError { message }
+    }
+}
+
+pub enum BuildEvent<'a> {
+    TargetStart {
+        index: usize,
+        total: usize,
+        target: &'a str,
+    },
+    ProjectStart {
+        name: &'a str,
+        profile: &'a str,
+        target: &'a str,
+    },
+    DepBuilding {
+        name: &'a str,
+        version: &'a str,
+    },
+    DepReady {
+        name: &'a str,
+        version: &'a str,
+        rebuilt: bool,
+    },
+    Compiling {
+        name: &'a str,
+        version: &'a str,
+    },
+    CompilerOutput {
+        stream: &'a str,
+        text: &'a str,
+    },
+    Finished {
+        secs: f64,
+    },
+}
+
+pub trait BuildReporter {
+    fn on_event(&mut self, event: BuildEvent<'_>);
+}
--- a/src/core/build/resolve.rs
+++ b/src/core/build/resolve.rs
@@ -0,0 +1,232 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use crate::core::build_config::Config;
+use crate::utils::build::{get_config_str, normalize_target_os, profile_table};
+
+pub(crate) fn get_config_value_raw(
+    config: &Config,
+    section: &str,
+    field: &str,
+    profile: &str,
+    target: Option<&str>,
+) -> Option<toml::Value> {
+    // Order: target.profile, profile.target, target, profile, base
+    let keys = [
+        target.map(|t| {
+            format!(
+                "{}.{}.{}.{}",
+                section,
+                normalize_target_os(t),
+                profile,
+                field
+            )
+        }),
+        target.map(|t| {
+            format!(
+                "{}.{}.{}.{}",
+                section,
+                profile,
+                normalize_target_os(t),
+                field
+            )
+        }),
+        target.map(|t| format!("{}.{}.{}", section, normalize_target_os(t), field)),
+        Some(format!("{}.{}.{}", section, profile, field)),
+        Some(format!("{}.{}", section, field)),
+    ];
+    for key in keys.into_iter().flatten() {
+        if let Some(val) = config.get(&key) {
+            return Some(val.clone());
+        }
+    }
+    None
+}
+
+pub(crate) fn get_inherit(
+    config: &Config,
+    section: &str,
+    profile: &str,
+    target: Option<&str>,
+) -> bool {
+    get_config_value_raw(config, section, "inherit", profile, target)
+        .and_then(|v| v.as_bool())
+        .unwrap_or(true)
+}
+
+pub(crate) fn get_config_value(
+    config: &Config,
+    section: &str,
+    field: &str,
+    profile: &str,
+    target: Option<&str>,
+) -> Option<String> {
+    get_config_value_raw(config, section, field, profile, target)
+        .and_then(|v| v.as_str().map(|s| s.trim().to_string()))
+        .filter(|s| !s.is_empty())
+}
+
+pub(crate) fn get_string_with_profile_and_target(
+    config: &Config,
+    field: &str,
+    profile: &str,
+    target: Option<&str>,
+) -> String {
+    if get_inherit(config, "build", profile, target) {
+        get_config_value(config, "build", field, profile, target)
+            .unwrap_or_else(|| get_config_str(config, &format!("build.{field}")))
+    } else {
+        get_config_value(config, "build", field, profile, target).unwrap_or_default()
+    }
+}
+
+pub fn get_build_string_with_profile(config: &Config, field: &str, profile: &str) -> String {
+    get_string_with_profile_and_target(config, field, profile, None)
+}
+
+pub(crate) fn get_lang_string(
+    config: &Config,
+    lang: &str,
+    field: &str,
+    profile: &str,
+    target: Option<&str>,
+) -> Option<String> {
+    get_config_value(config, &format!("build.{lang}"), field, profile, target)
+}
+
+pub(crate) fn get_lang_list(
+    config: &Config,
+    lang: &str,
+    field: &str,
+    profile: &str,
+    target: Option<&str>,
+) -> Result<Vec<String>, String> {
+    match get_config_value_raw(config, &format!("build.{lang}"), field, profile, target) {
+        Some(val) => parse_string_array(&val, field),
+        None => Ok(Vec::new()),
+    }
+}
+
+pub(crate) fn parse_string_array(value: &toml::Value, key: &str) -> Result<Vec<String>, String> {
+    let arr = value
+        .as_array()
+        .ok_or_else(|| format!("{key} must be an array of strings"))?;
+    let mut out = Vec::new();
+    for item in arr {
+        let s = item
+            .as_str()
+            .ok_or_else(|| format!("{key} must be an array of strings"))?;
+        out.push(s.to_string());
+    }
+    Ok(out)
+}
+
+pub(crate) fn get_list_with_profile_and_target(
+    config: &Config,
+    field: &str,
+    profile: &str,
+    target: Option<&str>,
+) -> Result<Vec<String>, String> {
+    let inherit = get_inherit(config, "build", profile, target);
+    let mut out = if inherit {
+        get_config_list(config, &format!("build.{field}"))?
+    } else {
+        Vec::new()
+    };
+    if let Some(val) = get_config_value_raw(config, "build", field, profile, target) {
+        if let Some(_arr) = val.as_array() {
+            let is_base = inherit
+                && config
+                    .get(&format!("build.{field}"))
+                    .map(|v| v == &val)
+                    .unwrap_or(false);
+            if !is_base {
+                let custom = parse_string_array(&val, &format!("build.{field}"))?;
+                if inherit {
+                    out.extend(custom);
+                } else {
+                    out = custom;
+                }
+            }
+        }
+    } else if inherit {
+        if let Some(table) = profile_table(config, profile)
+            && let Some(value) = table.get(field)
+        {
+            let mut extra = parse_string_array(value, &format!("build.{profile}.{field}"))?;
+            out.append(&mut extra);
+        }
+        if let Some(t) = target {
+            let normalized_t = normalize_target_os(t);
+            if let Some(table) = profile_table(config, normalized_t)
+                && let Some(value) = table.get(field)
+            {
+                let mut extra =
+                    parse_string_array(value, &format!("build.{normalized_t}.{field}"))?;
+                out.append(&mut extra);
+            }
+        }
+    }
+    Ok(out)
+}
+
+pub(crate) fn get_list_with_profile(
+    config: &Config,
+    field: &str,
+    profile: &str,
+) -> Result<Vec<String>, String> {
+    get_list_with_profile_and_target(config, field, profile, None)
+}
+
+pub(crate) fn get_targets(config: &Config, profile: &str) -> Result<Vec<String>, String> {
+    get_list_with_profile(config, "targets", profile)
+}
+
+pub(crate) fn get_config_list(config: &Config, key: &str) -> Result<Vec<String>, String> {
+    let value = match config.get(key) {
+        Some(v) => v,
+        None => return Ok(Vec::new()),
+    };
+    let arr = value
+        .as_array()
+        .ok_or_else(|| format!("{key} must be an array of strings"))?;
+    let mut out = Vec::new();
+    for item in arr {
+        let s = item
+            .as_str()
+            .ok_or_else(|| format!("{key} must be an array of strings"))?;
+        out.push(s.to_string());
+    }
+    Ok(out)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::utils::build::normalize_target_os;
+
+    #[test]
+    fn test_normalize_target_os() {
+        assert_eq!(normalize_target_os("linux"), "x86_64-unknown-linux-gnu");
+        assert_eq!(normalize_target_os("macos"), "x86_64-apple-darwin");
+        assert_eq!(normalize_target_os("windows"), "x86_64-pc-windows-msvc");
+        assert_eq!(
+            normalize_target_os("x86_64-unknown-linux-gnu"),
+            "x86_64-unknown-linux-gnu"
+        );
+        assert_eq!(normalize_target_os("unknown"), "unknown");
+    }
+}
--- a/src/core/build/steps.rs
+++ b/src/core/build/steps.rs
@@ -0,0 +1,398 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use crate::core::build::engine::ToolchainExecs;
+use crate::core::build_config::Config;
+use crate::utils::build::{VersionInfo, profile_table, substitute_vars};
+use glob::glob;
+use std::fs;
+use std::path::{Path, PathBuf};
+
+#[derive(Clone)]
+pub(crate) struct BuildStep {
+    name: String,
+    input: String,
+    output: String,
+    cmd: String,
+}
+
+pub(crate) struct StepVars<'a> {
+    pub(crate) profile: &'a str,
+    pub(crate) version: &'a str,
+    pub(crate) version_major: &'a str,
+    pub(crate) version_minor: &'a str,
+    pub(crate) version_patch: &'a str,
+    pub(crate) version_suffix: &'a str,
+    pub(crate) version_suffix_dash: &'a str,
+}
+
+fn get_build_steps_from_value(value: &toml::Value, key: &str) -> Result<Vec<BuildStep>, String> {
+    let arr = value
+        .as_array()
+        .ok_or_else(|| format!("{key} must be an array"))?;
+    let mut out = Vec::new();
+    for item in arr {
+        let tbl = item
+            .as_table()
+            .ok_or_else(|| format!("{key} entries must be tables"))?;
+        let name = tbl
+            .get("name")
+            .and_then(|v| v.as_str())
+            .unwrap_or("")
+            .trim()
+            .to_string();
+        let input = tbl
+            .get("in")
+            .and_then(|v| v.as_str())
+            .unwrap_or("")
+            .trim()
+            .to_string();
+        let output = tbl
+            .get("out")
+            .and_then(|v| v.as_str())
+            .unwrap_or("")
+            .trim()
+            .to_string();
+        let cmd = tbl
+            .get("cmd")
+            .and_then(|v| v.as_str())
+            .unwrap_or("")
+            .trim()
+            .to_string();
+        if name.is_empty() || input.is_empty() || output.is_empty() || cmd.is_empty() {
+            return Err(format!("{key} entries must include name, in, out, cmd"));
+        }
+        out.push(BuildStep {
+            name,
+            input,
+            output,
+            cmd,
+        });
+    }
+    Ok(out)
+}
+
+pub(crate) fn get_build_steps_with_profile(
+    config: &Config,
+    field: &str,
+    profile: &str,
+) -> Result<Vec<BuildStep>, String> {
+    if let Some(table) = profile_table(config, profile)
+        && let Some(value) = table.get(field)
+    {
+        return get_build_steps_from_value(value, &format!("build.{profile}.{field}"));
+    }
+    get_build_steps(config, &format!("build.{field}"))
+}
+
+fn get_build_steps(config: &Config, key: &str) -> Result<Vec<BuildStep>, String> {
+    let value = match config.get(key) {
+        Some(v) => v,
+        None => return Ok(Vec::new()),
+    };
+    get_build_steps_from_value(value, key)
+}
+
+use crate::core::build::report::{BuildEvent, BuildReporter};
+use std::sync::{Arc, atomic::AtomicBool};
+
+pub(crate) fn run_build_steps(
+    steps: &[BuildStep],
+    tools: &ToolchainExecs,
+    step_flags: &str,
+    vars: &StepVars,
+    cancel: &Arc<AtomicBool>,
+    rep: &mut dyn BuildReporter,
+) -> Result<(), String> {
+    for step in steps {
+        if cancel.load(std::sync::atomic::Ordering::SeqCst) {
+            return Err("Build interrupted".to_string());
+        }
+        run_build_step(step, tools, step_flags, vars, cancel, rep)?;
+    }
+    Ok(())
+}
+
+fn run_build_step(
+    step: &BuildStep,
+    tools: &ToolchainExecs,
+    step_flags: &str,
+    vars: &StepVars,
+    cancel: &Arc<AtomicBool>,
+    rep: &mut dyn BuildReporter,
+) -> Result<(), String> {
+    let input_pattern = expand_step_value(&step.input, "", vars);
+    let inputs = expand_glob(&input_pattern)?;
+    if inputs.is_empty() {
+        return Ok(());
+    }
+    let needs_stem = step.output.contains("{stem}");
+    if inputs.len() > 1 && !needs_stem {
+        return Err(format!(
+            "build.steps '{}' output must include {{stem}} for multiple inputs",
+            step.name
+        ));
+    }
+    for input in inputs {
+        if !input.is_file() {
+            continue;
+        }
+        let stem = input.file_stem().and_then(|v| v.to_str()).unwrap_or("");
+        let out_path = PathBuf::from(expand_step_value(&step.output, stem, vars));
+        if !should_run_step(&input, &out_path) {
+            continue;
+        }
+        if let Some(parent) = out_path.parent() {
+            fs::create_dir_all(parent)
+                .map_err(|err| format!("Failed to create step output dir: {err}"))?;
+        }
+        let cmd = substitute_step_cmd(&step.cmd, &input, &out_path, tools, step_flags, stem, vars);
+        let status = run_shell_command(&cmd, cancel, rep)
+            .map_err(|err| format!("Failed to run step '{}': {err}", step.name))?;
+        if !status.success() {
+            return Err(format!("Step '{}' failed", step.name));
+        }
+    }
+    Ok(())
+}
+
+pub(crate) fn clean_generated_files(patterns: &[String]) -> Result<(), String> {
+    for pattern in patterns {
+        for path in expand_glob(pattern)? {
+            if path.is_file() {
+                let _ = fs::remove_file(&path);
+            }
+        }
+    }
+    Ok(())
+}
+
+pub(crate) fn expand_glob(pattern: &str) -> Result<Vec<PathBuf>, String> {
+    let mut out = Vec::new();
+    let entries = glob(pattern).map_err(|err| format!("glob error: {err}"))?;
+    for entry in entries {
+        let path = entry.map_err(|err| format!("glob error: {err}"))?;
+        out.push(path);
+    }
+    Ok(out)
+}
+
+pub(crate) fn verify_expectations(patterns: &[String], vars: &StepVars) -> Result<(), String> {
+    for pattern in patterns {
+        let expanded = expand_step_value(pattern, "", vars);
+        let matches = expand_glob(&expanded)?;
+        if matches.is_empty() {
+            return Err(format!("Expected artifact not found: {expanded}"));
+        }
+    }
+    Ok(())
+}
+
+fn should_run_step(input: &Path, output: &Path) -> bool {
+    let in_time = fs::metadata(input).and_then(|m| m.modified());
+    let out_time = fs::metadata(output).and_then(|m| m.modified());
+    match (in_time, out_time) {
+        (Ok(i), Ok(o)) => i > o,
+        (Ok(_), Err(_)) => true,
+        _ => true,
+    }
+}
+
+fn substitute_step_cmd(
+    template: &str,
+    input: &Path,
+    output: &Path,
+    tools: &ToolchainExecs,
+    step_flags: &str,
+    stem: &str,
+    vars: &StepVars,
+) -> String {
+    let info = make_version_info(vars);
+    let s = substitute_vars(template, &info, vars.profile, "");
+    s.replace("{in}", &input.to_string_lossy())
+        .replace("{out}", &output.to_string_lossy())
+        .replace("{uic}", &tools.uic)
+        .replace("{moc}", &tools.moc)
+        .replace("{rcc}", &tools.rcc)
+        .replace("{cflags}", step_flags)
+        .replace("{stem}", stem)
+}
+
+pub(crate) fn build_step_flags(
+    cflags: &[String],
+    include_dirs: &[String],
+    compiler: &str,
+) -> String {
+    let mut out = Vec::new();
+    let msvc_style = is_msvc_compiler(compiler) || cflags.iter().any(|f| f.starts_with('/'));
+    for flag in cflags {
+        if flag.starts_with("-I") || flag.starts_with("-D") {
+            out.push(flag.clone());
+        }
+        if flag.starts_with("/I") || flag.starts_with("/D") {
+            out.push(flag.clone());
+        }
+        if msvc_style && flag.starts_with("-D") {
+            out.push(format!("/D{}", flag.trim_start_matches("-D")));
+        }
+    }
+    for dir in include_dirs {
+        out.push(format!("-I{dir}"));
+        if msvc_style {
+            out.push(format!("/I{dir}"));
+        }
+    }
+    out.sort();
+    out.dedup();
+    out.into_iter()
+        .map(quote_step_arg)
+        .collect::<Vec<_>>()
+        .join(" ")
+}
+
+fn quote_step_arg(arg: String) -> String {
+    if !arg.chars().any(|c| c.is_whitespace() || c == '"') {
+        return arg;
+    }
+    let escaped = arg.replace('"', "\\\"");
+    format!("\"{escaped}\"")
+}
+
+fn is_msvc_compiler(compiler: &str) -> bool {
+    let lower = compiler.to_lowercase();
+    lower.contains("cl.exe")
+        || lower == "cl"
+        || lower.contains("clang-cl")
+        || lower.contains("msvc")
+}
+
+fn run_shell_command(
+    cmd: &str,
+    cancel: &Arc<AtomicBool>,
+    rep: &mut dyn BuildReporter,
+) -> Result<std::process::ExitStatus, std::io::Error> {
+    let mut child = if cfg!(target_os = "windows") {
+        std::process::Command::new("cmd")
+            .arg("/C")
+            .arg(cmd)
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .spawn()
+    } else {
+        std::process::Command::new("sh")
+            .arg("-c")
+            .arg(cmd)
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .spawn()
+    }?;
+
+    let stdout = child.stdout.take().unwrap();
+    let stderr = child.stderr.take().unwrap();
+
+    use std::io::{BufRead, BufReader};
+    use std::sync::mpsc;
+
+    let (tx, rx) = mpsc::channel();
+
+    let cancel_clone = cancel.clone();
+    let tx_stdout = tx.clone();
+    let stdout_thread = std::thread::spawn(move || {
+        let reader = BufReader::new(stdout);
+        for line in reader.lines() {
+            if cancel_clone.load(std::sync::atomic::Ordering::SeqCst) {
+                break;
+            }
+            if let Ok(line) = line {
+                let _ = tx_stdout.send(("stdout", line));
+            }
+        }
+    });
+
+    let cancel_clone = cancel.clone();
+    let tx_stderr = tx.clone();
+    let stderr_thread = std::thread::spawn(move || {
+        let reader = BufReader::new(stderr);
+        for line in reader.lines() {
+            if cancel_clone.load(std::sync::atomic::Ordering::SeqCst) {
+                break;
+            }
+            if let Ok(line) = line {
+                let _ = tx_stderr.send(("stderr", line));
+            }
+        }
+    });
+
+    let status = child.wait()?;
+    let _ = stdout_thread.join();
+    let _ = stderr_thread.join();
+
+    drop(tx);
+    while let Ok((stream, text)) = rx.recv() {
+        rep.on_event(BuildEvent::CompilerOutput {
+            stream,
+            text: &text,
+        });
+    }
+
+    Ok(status)
+}
+
+pub(crate) fn build_steps_need_run(steps: &[BuildStep], vars: &StepVars) -> Result<bool, String> {
+    for step in steps {
+        let input_pattern = expand_step_value(&step.input, "", vars);
+        let inputs = expand_glob(&input_pattern)?;
+        if inputs.is_empty() {
+            continue;
+        }
+        let needs_stem = step.output.contains("{stem}");
+        if inputs.len() > 1 && !needs_stem {
+            return Err(format!(
+                "build.steps '{}' output must include {{stem}} for multiple inputs",
+                step.name
+            ));
+        }
+        for input in inputs {
+            if !input.is_file() {
+                continue;
+            }
+            let stem = input.file_stem().and_then(|v| v.to_str()).unwrap_or("");
+            let out_path = PathBuf::from(expand_step_value(&step.output, stem, vars));
+            if should_run_step(&input, &out_path) {
+                return Ok(true);
+            }
+        }
+    }
+    Ok(false)
+}
+
+fn make_version_info(vars: &StepVars) -> VersionInfo {
+    VersionInfo {
+        full: vars.version.to_string(),
+        major: vars.version_major.to_string(),
+        minor: vars.version_minor.to_string(),
+        patch: vars.version_patch.to_string(),
+        suffix: vars.version_suffix.to_string(),
+        suffix_dash: vars.version_suffix_dash.to_string(),
+    }
+}
+
+fn expand_step_value(template: &str, stem: &str, vars: &StepVars) -> String {
+    let info = make_version_info(vars);
+    let s = substitute_vars(template, &info, vars.profile, "");
+    s.replace("{stem}", stem)
+}
--- a/src/core/build_config.rs
+++ b/src/core/build_config.rs
@@ -21,6 +21,7 @@ use std::fs;
 use std::path::{Path, PathBuf};
 use toml::Value;
 use toml::map::Map;
+use toml_edit::{DocumentMut, Item, Table};

 const DEFAULT_VERSION: &str = "0.1.0";
 const DEFAULT_LANGUAGE: &str = "c";
@@ -42,6 +43,7 @@ pub enum ConfigError {
    Io(std::io::Error),
    TomlDe(toml::de::Error),
    TomlSer(toml::ser::Error),
+    TomlEdit(toml_edit::TomlError),
    Invalid(String),
 }

@@ -51,6 +53,7 @@ impl std::fmt::Display for ConfigError {
            ConfigError::Io(err) => write!(f, "I/O error: {err}"),
            ConfigError::TomlDe(err) => write!(f, "TOML parse error: {err}"),
            ConfigError::TomlSer(err) => write!(f, "TOML serialize error: {err}"),
+            ConfigError::TomlEdit(err) => write!(f, "TOML parse error: {err}"),
            ConfigError::Invalid(msg) => write!(f, "Invalid config: {msg}"),
        }
    }
@@ -80,6 +83,10 @@ pub struct Config {
    path: PathBuf,
    data: Value,
    typed: DcrConfig,
+    /// Editable document mirror of `data`, used for serialization. It preserves
+    /// comments, formatting, and any keys not modeled by the typed/raw views, so
+    /// `save()` never drops unknown sections (e.g. `[run]`, `[[build.post_steps]]`).
+    doc: DocumentMut,
 }

 #[allow(dead_code)]
@@ -105,14 +112,24 @@ pub struct PackageConfig {
    pub pkg_type: Option<String>,
 }

+fn default_language() -> LanguageConfig {
+    LanguageConfig::One(DEFAULT_LANGUAGE.to_string())
+}
+
+fn default_compiler() -> String {
+    DEFAULT_COMPILER.to_string()
+}
+
 #[allow(dead_code)]
 #[derive(Debug, Clone, Deserialize)]
 pub struct BuildConfig {
+    #[serde(default = "default_language")]
    pub language: LanguageConfig,
    #[serde(default)]
    pub standard: Option<String>,
    #[serde(default)]
    pub cxx_standard: Option<String>,
+    #[serde(default = "default_compiler")]
    pub compiler: String,
    #[serde(default)]
    pub kind: Option<String>,
@@ -182,20 +199,29 @@ pub struct WorkspaceMemberConfig {
    pub path: String,
    #[serde(default)]
    pub deps: Vec<String>,
+    #[serde(default)]
+    pub main: Option<bool>,
 }

 impl Config {
    pub fn new(path: &str) -> Result<Self, ConfigError> {
        let path = PathBuf::from(path);
-        let data = if path.exists() {
-            read_toml(&path)?
+        let (data, doc) = if path.exists() {
+            load_parts(&path)?
        } else {
-            let default_value = default_toml()?;
-            write_toml(&path, &default_value)?;
-            default_value
+            let content = default_toml_text();
+            let doc: DocumentMut = content.parse().map_err(ConfigError::TomlEdit)?;
+            fs::write(&path, doc.to_string())?;
+            let data: Value = toml::from_str(&content)?;
+            (data, doc)
        };
        let typed = parse_typed_config(&data)?;
-        let cfg = Self { path, data, typed };
+        let cfg = Self {
+            path,
+            data,
+            typed,
+            doc,
+        };
        cfg.validate()?;
        Ok(cfg)
    }
@@ -205,9 +231,14 @@ impl Config {
        if !path.exists() {
            return Err(ConfigError::Invalid("dcr.toml not found".into()));
        }
-        let data = read_toml(&path)?;
+        let (data, doc) = load_parts(&path)?;
        let typed = parse_typed_config(&data)?;
-        let cfg = Self { path, data, typed };
+        let cfg = Self {
+            path,
+            data,
+            typed,
+            doc,
+        };
        cfg.validate()?;
        Ok(cfg)
    }
@@ -347,6 +378,13 @@ impl Config {
            .as_ref()
            .ok_or_else(|| ConfigError::Invalid("missing [build] section (required)".into()))?;

+        // For workspace_only projects, [build] section is optional
+        // and language/compiler are not required
+        if build.workspace_only {
+            self.validate_workspace()?;
+            return Ok(());
+        }
+
        if pkg.name.trim().is_empty() {
            return Err(ConfigError::Invalid("package.name is empty".into()));
        }
@@ -421,22 +459,35 @@ impl Config {
    }

    pub fn save(&self) -> Result<(), ConfigError> {
-        write_toml(&self.path, &self.data)
+        fs::write(&self.path, self.doc.to_string())?;
+        Ok(())
    }

    fn set(&mut self, key: &str, value: Value) -> Result<(), ConfigError> {
        let parts: Vec<&str> = key.split('.').collect();
-        let previous = self.data.clone();
-        set_path(&mut self.data, &parts, value)?;
+        let previous_data = self.data.clone();
+        let previous_doc = self.doc.clone();
+
+        if let Err(err) = set_doc_path(&mut self.doc, &parts, &value) {
+            self.doc = previous_doc;
+            return Err(err);
+        }
+        if let Err(err) = set_path(&mut self.data, &parts, value) {
+            self.data = previous_data;
+            self.doc = previous_doc;
+            return Err(err);
+        }
        self.typed = match parse_typed_config(&self.data) {
            Ok(typed) => typed,
            Err(err) => {
-                self.data = previous;
+                self.data = previous_data;
+                self.doc = previous_doc;
                return Err(err);
            }
        };
        if let Err(err) = self.validate() {
-            self.data = previous;
+            self.data = previous_data;
+            self.doc = previous_doc;
            self.typed = parse_typed_config(&self.data)?;
            return Err(err);
        }
@@ -658,235 +709,119 @@ impl Config {
    }
 }

-fn read_toml(path: &Path) -> Result<Value, ConfigError> {
+fn load_parts(path: &Path) -> Result<(Value, DocumentMut), ConfigError> {
    let content = fs::read_to_string(path)?;
-    Ok(toml::from_str(&content)?)
+    let data: Value = toml::from_str(&content)?;
+    let doc: DocumentMut = content.parse().map_err(ConfigError::TomlEdit)?;
+    Ok((data, doc))
 }

-fn write_toml(path: &Path, value: &Value) -> Result<(), ConfigError> {
-    let content = format_toml(value)?;
-    fs::write(path, content)?;
-    Ok(())
-}
-
-fn default_toml() -> Result<Value, ConfigError> {
+fn default_toml_text() -> String {
    let name = std::env::current_dir()
        .ok()
        .and_then(|p| p.file_name().map(|v| v.to_string_lossy().to_string()))
        .unwrap_or_else(|| "project".to_string());

-    let mut package = Map::new();
-    package.insert("name".to_string(), Value::String(name));
-    package.insert(
-        "version".to_string(),
-        Value::String(DEFAULT_VERSION.to_string()),
-    );
-    package.insert("type".to_string(), Value::String("none".to_string()));
-    package.insert("description".to_string(), Value::String("".to_string()));
-    package.insert("author".to_string(), Value::String("".to_string()));
-    package.insert(
-        "license".to_string(),
-        Value::String("GPL-3.0-or-later".to_string()),
-    );
-
-    let mut build = Map::new();
-    build.insert(
-        "language".to_string(),
-        Value::String(DEFAULT_LANGUAGE.to_string()),
-    );
-    build.insert(
-        "standard".to_string(),
-        Value::String(DEFAULT_STANDARD.to_string()),
-    );
-    build.insert(
-        "compiler".to_string(),
-        Value::String(DEFAULT_COMPILER.to_string()),
-    );
-    build.insert("kind".to_string(), Value::String(DEFAULT_KIND.to_string()));
-
-    let mut root = Map::new();
-    root.insert("package".to_string(), Value::Table(package));
-    root.insert("build".to_string(), Value::Table(build));
-    root.insert("dependencies".to_string(), Value::Table(Map::new()));
-
-    Ok(Value::Table(root))
+    format!(
+        "[package]\n\
+         name = \"{name}\"\n\
+         version = \"{DEFAULT_VERSION}\"\n\
+         type = \"none\"\n\
+         description = \"\"\n\
+         author = \"\"\n\
+         license = \"GPL-3.0-or-later\"\n\
+         \n\
+         [build]\n\
+         language = \"{DEFAULT_LANGUAGE}\"\n\
+         standard = \"{DEFAULT_STANDARD}\"\n\
+         compiler = \"{DEFAULT_COMPILER}\"\n\
+         kind = \"{DEFAULT_KIND}\"\n\
+         \n\
+         [dependencies]\n"
+    )
 }

-fn format_toml(value: &Value) -> Result<String, ConfigError> {
-    let root = value
-        .as_table()
-        .ok_or_else(|| ConfigError::Invalid("root is not a table".into()))?;
-
-    let package = root
-        .get("package")
-        .and_then(|v| v.as_table())
-        .ok_or_else(|| ConfigError::Invalid("missing [package]".into()))?;
-    let build = root
-        .get("build")
-        .and_then(|v| v.as_table())
-        .ok_or_else(|| ConfigError::Invalid("missing [build]".into()))?;
-    let deps = root
-        .get("dependencies")
-        .and_then(|v| v.as_table())
-        .ok_or_else(|| ConfigError::Invalid("missing [dependencies]".into()))?;
-    let toolchain = root.get("toolchain").and_then(|v| v.as_table());
-
-    let name = package.get("name").and_then(|v| v.as_str()).unwrap_or("");
-    let version = package
-        .get("version")
-        .and_then(|v| v.as_str())
-        .unwrap_or("");
-
-    let language_value = build.get("language");
-    let language = match language_value {
-        Some(Value::String(s)) => s.to_string(),
-        Some(Value::Array(arr)) => format_string_array(&Value::Array(arr.clone())),
-        _ => "".to_string(),
-    };
-    let standard = build.get("standard").and_then(|v| v.as_str()).unwrap_or("");
-    let compiler = build.get("compiler").and_then(|v| v.as_str()).unwrap_or("");
-
-    let mut out = String::new();
-    out.push_str("[package]\n");
-    out.push_str(&format!("name = \"{name}\"\n"));
-    out.push_str(&format!("version = \"{version}\"\n"));
-
-    for key in [
-        "type",
-        "description",
-        "author",
-        "authors",
-        "homepage",
-        "license",
-        "repository",
-        "readme",
-        "keywords",
-        "categories",
-    ] {
-        if let Some(val) = package.get(key) {
-            match val {
-                Value::String(s) => out.push_str(&format!("{key} = \"{s}\"\n")),
-                Value::Array(_) => out.push_str(&format!("{key} = {}\n", format_string_array(val))),
-                _ => {}
+fn set_doc_path(doc: &mut DocumentMut, path: &[&str], value: &Value) -> Result<(), ConfigError> {
+    let mut current = doc.as_table_mut();
+    for &key in &path[..path.len().saturating_sub(1)] {
+        if !current.contains_key(key) {
+            current.insert(key, Item::Table(Table::new()));
        }
+        current = current
+            .get_mut(key)
+            .and_then(|item| item.as_table_mut())
+            .ok_or_else(|| ConfigError::Invalid(format!("'{key}' is not a table")))?;
    }
-    }
-    out.push('\n');

-    out.push_str("[build]\n");
-    if language.starts_with('[') {
-        out.push_str(&format!("language = {language}\n"));
+    if let Some(&last) = path.last() {
+        current.insert(last, value_to_item(value));
+        Ok(())
    } else {
-        out.push_str(&format!("language = \"{language}\"\n"));
+        Err(ConfigError::Invalid("empty key".into()))
    }
-    if !standard.is_empty() {
-        out.push_str(&format!("standard = \"{standard}\"\n"));
-    }
-    out.push_str(&format!("compiler = \"{compiler}\"\n"));
-    let kind = build
-        .get("kind")
-        .and_then(|v| v.as_str())
-        .unwrap_or(DEFAULT_KIND);
-    out.push_str(&format!("kind = \"{kind}\"\n"));
-    if let Some(target) = build.get("target").and_then(|v| v.as_str())
-        && !target.trim().is_empty()
-    {
-        out.push_str(&format!("target = \"{target}\"\n"));
-    }
-    if let Some(out_dir) = build.get("out_dir").and_then(|v| v.as_str())
-        && !out_dir.trim().is_empty()
-    {
-        out.push_str(&format!("out_dir = \"{out_dir}\"\n"));
-    }
-    if let Some(cflags) = build.get("cflags") {
-        out.push_str(&format!("cflags = {}\n", format_string_array(cflags)));
-    }
-    if let Some(ldflags) = build.get("ldflags") {
-        out.push_str(&format!("ldflags = {}\n", format_string_array(ldflags)));
-    }
-    out.push('\n');
-
-    if let Some(toolchain) = toolchain {
-        let mut lines = Vec::new();
-        for key in ["cc", "cxx", "as", "ar", "ld"] {
-            if let Some(value) = toolchain.get(key).and_then(|v| v.as_str())
-                && !value.trim().is_empty()
-            {
-                lines.push(format!("{key} = \"{value}\""));
-            }
-        }
-        if !lines.is_empty() {
-            out.push_str("[toolchain]\n");
-            for line in lines {
-                out.push_str(&format!("{line}\n"));
-            }
-            out.push('\n');
-        }
-    }
-
-    out.push_str("[dependencies]\n");
-    if !deps.is_empty() {
-        let mut keys: Vec<&String> = deps.keys().collect();
-        keys.sort();
-        for key in keys {
-            if let Some(val) = deps.get(key) {
-                out.push_str(&format!("{key} = {}\n", format_dep_value(val)));
-            }
-        }
-    }
-    Ok(out)
 }

-fn format_dep_value(value: &Value) -> String {
+fn value_to_item(value: &Value) -> Item {
+    Item::Value(value_to_edit_value(value))
+}
+
+fn value_to_edit_value(value: &Value) -> toml_edit::Value {
    match value {
-        Value::String(s) => format!("\"{s}\""),
+        Value::String(s) => toml_edit::Value::from(s.clone()),
+        Value::Integer(i) => toml_edit::Value::from(*i),
+        Value::Float(f) => toml_edit::Value::from(*f),
+        Value::Boolean(b) => toml_edit::Value::from(*b),
+        Value::Datetime(dt) => {
+            let s = dt.to_string();
+            s.parse::<toml_edit::Datetime>()
+                .map(toml_edit::Value::from)
+                .unwrap_or_else(|_| toml_edit::Value::from(s))
+        }
+        Value::Array(arr) => {
+            let mut out = toml_edit::Array::new();
+            for item in arr {
+                out.push(value_to_edit_value(item));
+            }
+            toml_edit::Value::Array(out)
+        }
        Value::Table(tbl) => {
-            let mut parts = Vec::new();
-            if let Some(v) = tbl.get("version").and_then(|v| v.as_str()) {
-                parts.push(format!("version = \"{v}\""));
+            let mut out = toml_edit::InlineTable::new();
+            for key in ordered_table_keys(tbl) {
+                if let Some(v) = tbl.get(&key) {
+                    out.insert(&key, value_to_edit_value(v));
                }
-            if let Some(v) = tbl.get("path").and_then(|v| v.as_str()) {
-                parts.push(format!("path = \"{v}\""));
            }
-            if let Some(v) = tbl.get("git").and_then(|v| v.as_str()) {
-                parts.push(format!("git = \"{v}\""));
+            toml_edit::Value::InlineTable(out)
        }
-            if let Some(v) = tbl.get("branch").and_then(|v| v.as_str()) {
-                parts.push(format!("branch = \"{v}\""));
-            }
-            if let Some(v) = tbl.get("tag").and_then(|v| v.as_str()) {
-                parts.push(format!("tag = \"{v}\""));
-            }
-            if let Some(v) = tbl.get("rev").and_then(|v| v.as_str()) {
-                parts.push(format!("rev = \"{v}\""));
-            }
-            if let Some(v) = tbl.get("default-features").and_then(|v| v.as_bool()) {
-                parts.push(format!(
-                    "default-features = {}",
-                    if v { "true" } else { "false" }
-                ));
-            }
-            if let Some(v) = tbl.get("features") {
-                parts.push(format!("features = {}", format_string_array(v)));
-            }
-            if let Some(v) = tbl.get("system").and_then(|v| v.as_bool()) {
-                parts.push(format!("system = {}", if v { "true" } else { "false" }));
-            }
-            format!("{{ {} }}", parts.join(", "))
-        }
-        _ => "\"\"".to_string(),
    }
 }

-fn format_string_array(value: &Value) -> String {
-    if let Some(arr) = value.as_array() {
-        let items: Vec<String> = arr
+const DEP_KEY_ORDER: &[&str] = &[
+    "version",
+    "path",
+    "git",
+    "branch",
+    "tag",
+    "rev",
+    "default-features",
+    "features",
+    "system",
+];
+
+fn ordered_table_keys(tbl: &Map<String, Value>) -> Vec<String> {
+    let mut keys: Vec<String> = DEP_KEY_ORDER
        .iter()
-            .filter_map(|v| v.as_str().map(|s| format!("\"{s}\"")))
+        .filter(|k| tbl.contains_key(**k))
+        .map(|k| (*k).to_string())
        .collect();
-        return format!("[{}]", items.join(", "));
-    }
-    "[]".to_string()
+    let mut rest: Vec<String> = tbl
+        .keys()
+        .filter(|k| !DEP_KEY_ORDER.contains(&k.as_str()))
+        .cloned()
+        .collect();
+    rest.sort();
+    keys.extend(rest);
+    keys
 }

 fn get_path<'a>(value: &'a Value, path: &[&str]) -> Option<&'a Value> {
@@ -1135,6 +1070,84 @@ mod tests {
        );
    }

+    #[test]
+    fn save_preserves_untyped_sections() {
+        let dir = temp_dir("preserve_untyped");
+        let path = write_toml_file(
+            &dir,
+            "# top comment\n\
+             [package]\n\
+             name = \"test\"\n\
+             version = \"0.1.0\"\n\n\
+             [build]\n\
+             language = \"c\"\n\
+             standard = \"c11\"\n\
+             compiler = \"clang\"\n\
+             kind = \"elf\"\n\
+             filename = \"KERNEL\"\n\
+             extension = \"ELF\"\n\
+             inherit = false\n\
+             include = [\"src/include\"]\n\n\
+             [[build.post_steps]]\n\
+             name = \"iso\"\n\
+             cmd = \"grub-mkrescue\"\n\n\
+             [run]\n\
+             cmd = \"qemu-system-aarch64 -kernel KERNEL\"\n\n\
+             [dependencies]\n",
+        );
+
+        let mut config = Config::open(&path.to_string_lossy()).unwrap();
+        config
+            .set("dependencies.zlib", {
+                let mut tbl = Map::new();
+                tbl.insert("path".to_string(), Value::String("../zlib".to_string()));
+                Value::Table(tbl)
+            })
+            .unwrap();
+
+        // Reload from disk and confirm nothing modeled-but-not-whitelisted was dropped.
+        let reloaded = Config::open(&path.to_string_lossy()).unwrap();
+        assert_eq!(
+            reloaded.get("build.filename").and_then(|v| v.as_str()),
+            Some("KERNEL"),
+            "build.filename must survive save"
+        );
+        assert_eq!(
+            reloaded.get("build.extension").and_then(|v| v.as_str()),
+            Some("ELF")
+        );
+        assert_eq!(
+            reloaded.get("build.inherit").and_then(|v| v.as_bool()),
+            Some(false)
+        );
+        assert!(
+            reloaded
+                .get("build.include")
+                .and_then(|v| v.as_array())
+                .is_some(),
+            "build.include array must survive save"
+        );
+        assert_eq!(
+            reloaded.get("run.cmd").and_then(|v| v.as_str()),
+            Some("qemu-system-aarch64 -kernel KERNEL"),
+            "[run] section must survive save"
+        );
+        assert!(
+            reloaded.get("build.post_steps").is_some(),
+            "[[build.post_steps]] must survive save"
+        );
+
+        let saved = fs::read_to_string(&path).unwrap();
+        assert!(
+            saved.contains("zlib = { path = \"../zlib\" }"),
+            "dependency must be an inline table, got:\n{saved}"
+        );
+        assert!(
+            saved.contains("# top comment"),
+            "leading comment must be preserved, got:\n{saved}"
+        );
+    }
+
    #[test]
    fn new_creates_default_config() {
        let dir = temp_dir("new_default");
--- a/src/core/builder/asm.rs
+++ b/src/core/builder/asm.rs
@@ -1,170 +0,0 @@
-use crate::core::builder::BuildContext;
-use crate::core::builder::common;
-use crate::platform;
-use std::path::Path;
-use std::process::Command;
-use std::time::Instant;
-
-pub fn build_assembly<F>(
-    ctx: &BuildContext,
-    backend_name: &str,
-    default_assembler: &str,
-    extensions: &[&str],
-    build_object: F,
-) -> Result<f64, String>
-where
-    F: Fn(&str, &str, &str, &BuildContext) -> Result<(), String> + Sync,
-{
-    let lang = ctx.language.to_lowercase();
-    if lang.split(',').any(|p| p.trim() != "asm") {
-        return Err(format!(
-            "{backend_name} backend requires build.language = \"asm\""
-        ));
-    }
-
-    let assembler = if ctx.compiler.is_empty() {
-        default_assembler
-    } else {
-        ctx.compiler
-    };
-
-    let start_time = Instant::now();
-    let sources = common::collect_sources(
-        ctx.source_roots,
-        extensions,
-        ctx.exclude_dirs,
-        ctx.include_paths,
-    )?;
-    let obj_dir = match ctx.target_dir {
-        Some(dir) => Path::new(dir).join("obj"),
-        None => Path::new("./target").join(ctx.profile).join("obj"),
-    };
-    let objects = build_objects_common(assembler, &sources, &obj_dir, ctx, &build_object)?;
-
-    if ctx.kind == "staticlib" {
-        return archive_staticlib(ctx, &objects, start_time);
-    }
-
-    link_objects(ctx, &objects, start_time)
-}
-
-fn build_objects_common<F>(
-    assembler: &str,
-    sources: &[String],
-    obj_dir: &Path,
-    ctx: &BuildContext,
-    build_object: &F,
-) -> Result<Vec<String>, String>
-where
-    F: Fn(&str, &str, &str, &BuildContext) -> Result<(), String> + Sync,
-{
-    let objects: Vec<String> = sources
-        .iter()
-        .map(|s| common::object_path(obj_dir, s, "o"))
-        .collect();
-
-    common::parallel_build(
-        sources.len(),
-        |i| build_object(assembler, &sources[i], &objects[i], ctx),
-        ctx.codegen_units,
-    )?;
-
-    Ok(objects)
-}
-
-fn archive_staticlib(
-    ctx: &BuildContext,
-    objects: &[String],
-    start_time: Instant,
-) -> Result<f64, String> {
-    let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
-    if !common::needs_link(objects, &lib_path) {
-        return Ok(common::elapsed_secs(start_time));
-    }
-
-    let archiver = ctx.archiver.unwrap_or(if cfg!(target_os = "windows") {
-        "lib"
-    } else {
-        "ar"
-    });
-
-    let mut cmd = Command::new(archiver);
-    if cfg!(target_os = "windows") && archiver == "lib" {
-        cmd.arg("/nologo").arg(format!("/OUT:{lib_path}"));
-    } else {
-        cmd.arg("rcs").arg(&lib_path);
-    }
-    for obj in objects {
-        cmd.arg(obj);
-    }
-
-    if ctx.verbose || std::env::var("DCR_DEBUG").is_ok() {
-        eprintln!("[dcr] {:?}", cmd);
-    }
-
-    match cmd.status() {
-        Ok(status) if status.success() => Ok(common::elapsed_secs(start_time)),
-        Ok(_) => Err("Build failed".to_string()),
-        Err(err) => Err(format!("Build failed: {err}")),
-    }
-}
-
-fn link_objects(
-    ctx: &BuildContext,
-    objects: &[String],
-    start_time: Instant,
-) -> Result<f64, String> {
-    let mut cmd = Command::new(ctx.linker.unwrap_or("cc"));
-    if ctx.kind == "sharedlib" {
-        if cfg!(target_os = "macos") {
-            cmd.arg("-dynamiclib");
-        } else {
-            cmd.arg("-shared");
-        }
-    }
-
-    for obj in objects {
-        cmd.arg(obj);
-    }
-    for dir in ctx.lib_dirs {
-        cmd.arg(format!("-L{dir}"));
-    }
-    for lib in ctx.libs {
-        cmd.arg(format!("-l{lib}"));
-    }
-    for flag in ctx.ldflags {
-        cmd.arg(flag);
-    }
-
-    let name = ctx.output_filename.unwrap_or(ctx.project_name);
-    let ext = ctx.output_extension.unwrap_or("");
-    let final_name = if ext.is_empty() {
-        name.to_string()
-    } else {
-        format!("{}.{}", name, ext)
-    };
-
-    let out_path = if ctx.kind == "sharedlib" {
-        platform::shared_lib_path(ctx.profile, &final_name, ctx.target_dir)
-    } else if ctx.kind == "elf" {
-        platform::elf_path(ctx.profile, &final_name, ctx.target_dir)
-    } else {
-        platform::bin_path(ctx.profile, &final_name, ctx.target_dir)
-    };
-
-    if !common::needs_link(objects, &out_path) {
-        return Ok(common::elapsed_secs(start_time));
-    }
-
-    cmd.arg("-o").arg(out_path);
-
-    if ctx.verbose || std::env::var("DCR_DEBUG").is_ok() {
-        eprintln!("[dcr] {:?}", cmd);
-    }
-
-    match cmd.status() {
-        Ok(status) if status.success() => Ok(common::elapsed_secs(start_time)),
-        Ok(_) => Err("Build failed".to_string()),
-        Err(err) => Err(format!("Build failed: {err}")),
-    }
-}
--- a/src/core/builder/mod.rs
+++ b/src/core/builder/mod.rs
@@ -1,124 +0,0 @@
-// DCR — Cargo-like C/C++ project manager.
-//
-// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-pub mod asm;
-pub mod common;
-pub mod fasm;
-pub mod gas;
-pub mod llvm_ir;
-pub mod masm;
-pub mod msvc;
-pub mod nasm;
-pub mod qt;
-pub mod unix_cc;
-
-pub struct BuildContext<'a> {
-    pub profile: &'a str,
-    pub project_name: &'a str,
-    pub compiler: &'a str,
-    pub language: &'a str,
-    pub standard: &'a str,
-    pub cxx_standard: &'a str,
-    pub target: Option<&'a str>,
-    pub target_dir: Option<&'a str>,
-    pub kind: &'a str,
-    pub platform: Option<&'a str>,
-    pub linker: Option<&'a str>,
-    pub archiver: Option<&'a str>,
-    pub moc: Option<&'a str>,
-    pub uic: Option<&'a str>,
-    pub rcc: Option<&'a str>,
-    pub package_type: Option<&'a str>,
-    pub freestanding: bool,
-    pub panic_abort: bool,
-    pub codegen_units: usize,
-    pub source_roots: &'a [std::path::PathBuf],
-    pub exclude_dirs: &'a [std::path::PathBuf],
-    pub include_paths: &'a [String],
-    pub include_dirs: &'a [String],
-    pub lib_dirs: &'a [String],
-    pub libs: &'a [String],
-    pub cflags: &'a [String],
-    pub ldflags: &'a [String],
-    pub output_filename: Option<&'a str>,
-    pub output_extension: Option<&'a str>,
-    pub verbose: bool,
-    pub qt: bool,
-}
-
-pub fn build(ctx: &BuildContext) -> Result<f64, String> {
-    let compiler = ctx.compiler.to_lowercase();
-    if !check_compiler_exists(ctx.compiler) {
-        return Err(format!(
-            "Compiler not found: {}. Make sure it is installed and available in PATH.",
-            ctx.compiler
-        ));
-    }
-    if compiler.contains("clang-cl") {
-        return msvc::build(ctx);
-    }
-    if compiler == "as" || compiler.contains("gas") {
-        return gas::build(ctx);
-    }
-    if compiler.contains("llc") {
-        return llvm_ir::build(ctx);
-    }
-    if compiler.contains("fasm") {
-        return fasm::build(ctx);
-    }
-    if compiler.contains("nasm") {
-        return nasm::build(ctx);
-    }
-    if compiler == "ml" || compiler == "ml64" || compiler.contains("masm") {
-        return masm::build(ctx);
-    }
-    if compiler == "cl" || compiler.contains("msvc") {
-        return msvc::build(ctx);
-    }
-    unix_cc::build(ctx)
-}
-
-fn check_compiler_exists(compiler: &str) -> bool {
-    let name = if compiler.is_empty() { "cc" } else { compiler };
-    std::process::Command::new(name)
-        .arg("--version")
-        .output()
-        .is_ok()
-}
-
-pub fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
-    let compiler = ctx.compiler.to_lowercase();
-    if compiler.contains("clang-cl") || compiler == "cl" || compiler.contains("msvc") {
-        return msvc::collect_sources(ctx);
-    }
-    if compiler == "as" || compiler.contains("gas") {
-        return gas::collect_sources(ctx);
-    }
-    if compiler.contains("llc") {
-        return llvm_ir::collect_sources(ctx);
-    }
-    if compiler.contains("fasm") {
-        return fasm::collect_sources(ctx);
-    }
-    if compiler.contains("nasm") {
-        return nasm::collect_sources(ctx);
-    }
-    if compiler == "ml" || compiler == "ml64" || compiler.contains("masm") {
-        return masm::collect_sources(ctx);
-    }
-    unix_cc::collect_sources(ctx)
-}
--- a/src/core/deps/mod.rs
+++ b/src/core/deps/mod.rs
@@ -103,6 +103,10 @@ pub fn resolve_deps(
                        }
                    } else {
                        push_if_exists(&mut resolved.include_dirs, &dep_root.join("include"));
+                        push_if_exists(
+                            &mut resolved.include_dirs,
+                            &dep_root.join("target").join("include"),
+                        );
                    }

                    if let Some(lib_dirs) = table.get("lib").and_then(|v| v.as_array()) {
@@ -128,6 +132,10 @@ pub fn resolve_deps(
                    }
                } else {
                    push_if_exists(&mut resolved.include_dirs, &dep_root.join("include"));
+                    push_if_exists(
+                        &mut resolved.include_dirs,
+                        &dep_root.join("target").join("include"),
+                    );
                    push_default_lib_dirs(&mut resolved.lib_dirs, &dep_root);
                    resolved.libs.push(name.clone());
                }
--- a/src/core/mod.rs
+++ b/src/core/mod.rs
@@ -15,8 +15,8 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

+pub mod build;
 pub mod build_config;
-pub mod builder;
 pub mod deps;
 pub mod registry;
 pub mod runner;
--- a/src/core/workspace.rs
+++ b/src/core/workspace.rs
@@ -50,7 +50,6 @@ pub fn parse_workspace(
    root: &Path,
 ) -> Result<Option<Workspace>, String> {
    let mut table = None;
-    // Order: workspace.target.profile, workspace.profile.target, workspace.target, workspace.profile, workspace
    let combinations = if let Some(t) = target {
        let normalized_t = normalize_target_os(t);
        vec![
--- a/src/utils/build.rs
+++ b/src/utils/build.rs
@@ -280,7 +280,7 @@ pub fn get_language_with_profile(config: &Config, profile: &str) -> Result<Strin
    }
    match config.get("build.language") {
        Some(v) => parse_language_value(v, "build.language"),
-        None => Err("build.language is missing".to_string()),
+        None => Ok("c".to_string()),
    }
 }

@@ -324,9 +324,14 @@ pub fn resolve_compiler(
    tc_as: Option<&str>,
 ) -> String {
    let lang = primary_language(language);
-    env_override_compiler(&lang)
+    let result = env_override_compiler(&lang)
        .or_else(|| toolchain_override_compiler(&lang, tc_cc, tc_cxx, tc_as))
-        .unwrap_or_else(|| compiler.to_string())
+        .unwrap_or_else(|| compiler.to_string());
+    if lang == "asm" {
+        map_asm_compiler(&result)
+    } else {
+        result
+    }
 }

 fn env_override_compiler(lang: &str) -> Option<String> {
@@ -369,7 +374,8 @@ fn toolchain_override_compiler(
    tc_as: Option<&str>,
 ) -> Option<String> {
    if lang == "asm" {
-        return tc_as.map(|v| v.to_string());
+        let as_compiler = tc_as.map(|v| v.to_string());
+        return as_compiler.map(|v| map_asm_compiler(&v));
    }
    if (lang == "c++" || lang == "cpp" || lang == "cxx")
        && let Some(v) = tc_cxx
@@ -379,23 +385,31 @@ fn toolchain_override_compiler(
    tc_cc.map(|v| v.to_string())
 }

+fn map_asm_compiler(compiler: &str) -> String {
+    match compiler.to_lowercase().as_str() {
+        "gas" | "gnu-as" => "as".to_string(),
+        "nasm" => "nasm".to_string(),
+        "fasm" | "fasm64" => "fasm".to_string(),
+        "masm" | "ml" | "ml64" => "ml".to_string(),
+        _ => compiler.to_string(),
+    }
+}
+
 pub fn primary_language(language: &str) -> String {
-    let parts: Vec<String> = language
+    let tokens: Vec<&str> = language
        .split(',')
-        .map(|p| p.trim().to_lowercase())
-        .filter(|p| !p.is_empty())
+        .map(|s| s.trim())
+        .filter(|s| !s.is_empty())
        .collect();
-    for p in &parts {
-        if p == "c++" || p == "cpp" || p == "cxx" {
-            return p.clone();
+    // Priority: c++ > c > asm.
+    for id in ["cxx", "c", "asm"] {
+        let hit = tokens.iter().any(|t| {
+            crate::core::build::language::language_for_token(t).map(|l| l.id()) == Some(id)
+        });
+        if hit {
+            return id.to_string();
        }
    }
-    if parts.iter().any(|p| p == "c") {
-        return "c".to_string();
-    }
-    if parts.iter().any(|p| p == "asm") {
-        return "asm".to_string();
-    }
    language.to_lowercase()
 }

--- a/tests/cli_build.rs
+++ b/tests/cli_build.rs
@@ -16,6 +16,48 @@ fn init_and_clean_remove_target() {
    assert!(!dir.join("target").exists(), "target should be removed");
 }

+#[test]
+fn add_preserves_run_and_untyped_keys() {
+    // Regression: `dcr add` used to drop the [run] section and non-whitelisted
+    // [build] keys (filename/extension/include) when re-serializing dcr.toml.
+    let dir = unique_sandbox_dir("preserve_add");
+    let out = run_dcr(&["init"], &dir);
+    assert!(out.status.success(), "dcr init should succeed");
+
+    let toml_path = dir.join("dcr.toml");
+    let toml = std::fs::read_to_string(&toml_path).expect("failed to read dcr.toml");
+    let updated = toml.replace(
+        "[build]",
+        "[build]\nfilename = \"KERNEL\"\nextension = \"ELF\"\ninclude = [\"src/include\"]",
+    ) + "\n[run]\ncmd = \"qemu-system-aarch64 -kernel KERNEL\"\n";
+    std::fs::write(&toml_path, updated).expect("failed to write dcr.toml");
+
+    let out = run_dcr(&["add", "zlib", "path:../zlib"], &dir);
+    assert!(out.status.success(), "dcr add should succeed");
+
+    let saved = std::fs::read_to_string(&toml_path).expect("failed to read dcr.toml");
+    assert!(
+        saved.contains("filename = \"KERNEL\""),
+        "build.filename lost:\n{saved}"
+    );
+    assert!(
+        saved.contains("extension = \"ELF\""),
+        "build.extension lost:\n{saved}"
+    );
+    assert!(
+        saved.contains("include = [\"src/include\"]"),
+        "build.include lost:\n{saved}"
+    );
+    assert!(
+        saved.contains("[run]") && saved.contains("qemu-system-aarch64"),
+        "[run] section lost:\n{saved}"
+    );
+    assert!(
+        saved.contains("zlib = { path = \"../zlib\" }"),
+        "dependency not added as inline table:\n{saved}"
+    );
+}
+
 #[test]
 fn build_run_clean_flags_normal_project() {
    let Some(compiler) = available_compiler() else {