rust: various build script fixes

lang/rust/buildrs-runner.rs

@@ -1,10 +0,0 @@
-use std::{env::var_os, fs::{create_dir, File}, os::unix::process::CommandExt, process::Command};
-
-fn main() {
-    create_dir(var_os("OUT_DIR").unwrap()).unwrap();
-    Err(Command::new(var_os("script").unwrap())
-        .stdout(File::create(var_os("out").unwrap()).unwrap())
-        .current_dir(var_os("cwd").unwrap())
-        .exec())
-    .unwrap()
-}

lang/rust/cfg-fetch.rs

@@ -1,10 +0,0 @@
-use std::{env::var_os, fs::{create_dir, File}, os::unix::process::CommandExt, process::Command};
-
-fn main() {
-    Err(
-        Command::new(var_os("rustc").unwrap())
-        .arg("--print=cfg")
-        .stdout(File::create(var_os("out").unwrap()).unwrap())
-        .exec())
-    .unwrap()
-}

lang/rust/default.nix

@@ -15,7 +15,8 @@
     xxd
   ];
   overrides.preBuild = ''
-    (cat buildrs-runner.rs; printf '\0') | xxd -i -n runner_source > runner_source.h
+    (cat ${./helpers/src/bin/buildscript-runner.rs}; printf '\0') | xxd -i -n runner_source > runner_source.h
-    (cat cfg-fetch.rs; printf '\0') | xxd -i -n cfgfetch_source > cfgfetch_source.h
+    (cat ${./helpers/src/bin/rustc-wrapper.rs}; printf '\0') | xxd -i -n rustc_wrap_source > rustc_wrap_source.h
+    (cat ${./helpers/src/bin/cfg-reader.rs}; printf '\0') | xxd -i -n cfgfetch_source > cfgfetch_source.h
   '';
 }

lang/rust/helpers/.gitignore

@@ -0,0 +1 @@
+/target

lang/rust/helpers/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "helpers"
+version = "0.1.0"

lang/rust/helpers/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "helpers"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

lang/rust/helpers/src/bin/buildscript-runner.rs

@@ -0,0 +1,70 @@
+use std::{
+    collections::HashMap,
+    env::{var, var_os},
+    fs::{File, create_dir},
+    io::{Read, Write},
+    os::unix::process::CommandExt,
+    process::Command,
+};
+
+fn parse(data: &str) -> HashMap<String, String> {
+    let mut out = HashMap::new();
+
+    let mut parse_one = |key: &str, value: String, fallback| match key {
+        "metadata" => {
+            let (left, right) = value
+                .split_once('=')
+                .expect("missing '=' for cargo::metadata");
+            out.insert(left.to_string(), right.to_string());
+        }
+
+        _ if fallback => {
+            out.insert(key.to_string(), value);
+        }
+
+        _ => {}
+    };
+
+    for line in data.lines() {
+        if let Some(data) = line.strip_prefix("cargo::") {
+            let (key, value) = data.split_once('=').expect("missing '=' on cargo:: line");
+            parse_one(key, value.to_string(), false);
+        } else if let Some(data) = line.strip_prefix("cargo:") {
+            let (key, value) = data.split_once('=').expect("missing '=' on cargo: line");
+            parse_one(key, value.to_string(), true);
+        }
+    }
+
+    out
+}
+
+fn main() {
+    create_dir(var_os("OUT_DIR").unwrap()).unwrap();
+
+    let mut f = File::create(var_os("out").unwrap()).unwrap();
+    writeln!(&mut f, "zilch: OUT_DIR={:?}", var("OUT_DIR").unwrap()).unwrap();
+
+    let mut cmd = Command::new(var_os("script").unwrap());
+
+    cmd.stdout(f).current_dir(var_os("cwd").unwrap());
+
+    if let Ok(inherit) = var("_zilch_links") {
+        if !inherit.is_empty() {
+            for v in inherit.split('!') {
+                let (path, name) = v.split_once(':').unwrap();
+                let mut file = File::open(path).unwrap();
+                let mut data = String::new();
+                file.read_to_string(&mut data).unwrap();
+
+                let data = parse(&data);
+                for (k, v) in data {
+                    let mut name = format!("DEP_{}_{}", name, k);
+                    name.make_ascii_uppercase();
+                    cmd.env(name.replace('-', "_"), v);
+                }
+            }
+        }
+    }
+
+    panic!("failed to exec: {:?}", cmd.exec())
+}

lang/rust/helpers/src/bin/cfg-reader.rs

@@ -0,0 +1,11 @@
+use std::{env::var_os, fs::File, os::unix::process::CommandExt, process::Command};
+
+fn main() {
+    panic!(
+        "{:?}",
+        Command::new(var_os("rustc").unwrap())
+            .arg("--print=cfg")
+            .stdout(File::create(var_os("out").unwrap()).unwrap())
+            .exec()
+    );
+}

lang/rust/helpers/src/bin/rustc-wrapper.rs

@@ -0,0 +1,122 @@
+use std::{
+    collections::HashMap,
+    env::{args, var_os},
+    io::Read,
+    os::unix::process::CommandExt,
+    process::Command,
+};
+
+#[derive(Default, Debug)]
+struct Data {
+    // Only available if this is the current crate.
+    pub env: Vec<String>,
+    pub cfg: Vec<String>,
+    pub check_cfg: Vec<String>,
+
+    // Only used for final linking phase. (TODO: check)
+    pub flags: Vec<String>,
+
+    pub link_arg: Vec<String>,
+    pub link_arg_bin: HashMap<Option<String>, Vec<String>>,
+    pub link_lib: Vec<String>,
+    pub link_search: Vec<String>,
+
+    // Propagates to _dependent_ packages.
+    pub metadata: HashMap<String, String>,
+}
+
+fn parse(data: &str) -> Data {
+    let mut out = Data::default();
+
+    let mut parse_one = |key, value, fallback| match key {
+        "rerun-if-changed" => {}
+        "rerun-if-env-changed" => {}
+
+        "rustc-env" => out.env.push(value),
+        "rustc-cfg" => out.cfg.push(value),
+        "rustc-check-cfg" => out.check_cfg.push(value),
+
+        "rustc-flags" => out.flags.push(value),
+        "rustc-link-arg" => out.link_arg.push(value),
+        "rustc-link-arg-bins" => out
+            .link_arg_bin
+            .entry(None)
+            .or_default()
+            .push(value.to_string()),
+        "rustc-link-arg-bin" => {
+            let (left, right) = value
+                .split_once('=')
+                .expect("missing '=' for cargo::rustc-link-arg-bin");
+            out.link_arg_bin
+                .entry(Some(left.to_string()))
+                .or_default()
+                .push(right.to_string());
+        }
+        "rustc-link-lib" => out.link_lib.push(value),
+        "rustc-link-search" => out.link_search.push(value),
+        "metadata" => {
+            let (left, right) = value
+                .split_once('=')
+                .expect("missing '=' for cargo::metadata");
+            out.metadata.insert(left.to_string(), right.to_string());
+        }
+
+        _ if fallback => {
+            out.metadata.insert(key.to_string(), value);
+        }
+
+        _ => {
+            panic!(
+                "unknown key-value pair cargo::{:?}={:?} and no fallback to cargo::metadata allowed",
+                key, value
+            )
+        }
+    };
+
+    for line in data.lines() {
+        if let Some(data) = line.strip_prefix("cargo::") {
+            let (key, value) = data.split_once('=').expect("missing '=' on cargo:: line");
+            parse_one(key, value.to_string(), false);
+        } else if let Some(data) = line.strip_prefix("cargo:") {
+            let (key, value) = data.split_once('=').expect("missing '=' on cargo: line");
+            parse_one(key, value.to_string(), true);
+        }
+    }
+
+    out
+}
+
+fn main() {
+    let mut cmd = Command::new(var_os("_zilch_rustc").unwrap());
+    if let Some(proc) = var_os("_zilch_proc") {
+        if !proc.is_empty() {
+            let mut file = std::fs::File::open(proc).unwrap();
+            let mut data = String::new();
+            file.read_to_string(&mut data).unwrap();
+            let data = parse(&data);
+            for item in data.env {
+                let (l, r) = item.split_once('=').unwrap();
+                cmd.env(l, r);
+            }
+            for item in data.check_cfg {
+                cmd.arg("--check-cfg").arg(item);
+            }
+            for item in data.cfg {
+                cmd.arg("--cfg").arg(item);
+            }
+            for item in data.link_search {
+                cmd.arg("-L").arg(item);
+            }
+            for item in data.link_arg {
+                cmd.arg("-C").arg(format!("link-arg={}", item));
+            }
+            for item in data.link_lib {
+                cmd.arg("-l").arg(item);
+            }
+        }
+    }
+
+    cmd.args(args().skip(1));
+
+    panic!("failed to exec: {:?}", cmd.exec())
+}

lang/rust/src/build-script.sld

@@ -11,39 +11,9 @@
   (zilch lang rust))
 
  (export
-   <build-script-output>
-   make-build-script-output build-script-output?
-   build-script-output-rerun-if-changed build-script-output-rerun-if-env-changed 
-   build-script-output-link-arg build-script-output-link-lib build-script-output-link-search
-   build-script-output-flags build-script-output-cfg build-script-output-check-cfg
-   build-script-output-env build-script-output-warning build-script-output-metadata
-
    call-runner)
 
  (begin
-   (define-record-type <build-script-output>
-     (make-build-script-output rerun-if-changed rerun-if-env-changed link-arg link-lib link-search flags cfg check-cfg env warning metadata)
-     build-script-output?
-     (rerun-if-changed build-script-output-rerun-if-changed set-build-script-output-rerun-if-changed!)
-     (rerun-if-env-changed build-script-output-rerun-if-env-changed set-build-script-output-rerun-if-env-changed!)
-     (link-arg build-script-output-link-arg set-build-script-output-link-arg!)
-     (link-lib build-script-output-link-lib set-build-script-output-link-lib!)
-     (link-search build-script-output-link-search set-build-script-output-link-search!)
-     (flags build-script-output-flags set-build-script-output-flags!)
-     (cfg build-script-output-cfg set-build-script-output-cfg!)
-     (check-cfg build-script-output-check-cfg set-build-script-output-check-cfg!)
-     (env build-script-output-env set-build-script-output-env!)
-     (warning build-script-output-warning set-build-script-output-warning!)
-     (metadata build-script-output-metadata set-build-script-output-metadata!))
-   (define-record-printer (<build-script-output> entry out)
-     (fprintf out "#<build-script-output changed:~S env-changed:~S flags:~S cfg:~S check-cfg:~S env:~S>"
-       (build-script-output-rerun-if-changed entry)
-       (build-script-output-rerun-if-env-changed entry)
-       (build-script-output-flags entry)
-       (build-script-output-cfg entry)
-       (build-script-output-check-cfg entry)
-       (build-script-output-env entry)))
-
    (define linker (delay (let ((v (cdr (assoc "out" (nixpkgs "gcc"))))) #~,(string-append #$v "/bin/cc"))))
 
    (foreign-declare "#include \"runner_source.h\"")
@@ -57,76 +27,13 @@
          #:edition "2021"
          #:emits '(#:link #t))))
   
-   (define (parse-build-script-line line out)
-     ;; Rewrite cargo:foo -> cargo::foo
-     (when (and (string-prefix? "cargo:" line) (not (string-prefix? "cargo::" line)))
-       (set! line (string-append "cargo::" (string-copy line 6))))
-     (cond
-      ((string-prefix? "cargo::rerun-if-changed=" line)
-       (set-build-script-output-rerun-if-changed! out (cons (string-copy line 24) (build-script-output-rerun-if-changed out))))
-      ((string-prefix? "cargo::rerun-if-env-changed=" line)
-       (set-build-script-output-rerun-if-env-changed! out (cons (string-copy line 28) (build-script-output-rerun-if-env-changed out))))
-      ((string-prefix? "cargo::rustc-flags=" line)
-       (set-build-script-output-flags! out (cons (string-copy line 19) (build-script-output-flags out))))
-      ((string-prefix? "cargo::rustc-cfg=" line)
-       (let* ((kv (string-copy line 17))
-              (splat-start (and (string-suffix? "\"" kv) (string-contains kv "=\""))))
-        (set-build-script-output-cfg! out
-          (cons
-            (if splat-start
-              (cons (string-copy kv 0 splat-start) (string-copy kv (+ splat-start 2) (- (string-length kv) 1)))
-              kv)
-            (build-script-output-cfg out)))))
-      ((string-prefix? "cargo::rustc-check-cfg=" line)
-       (set-build-script-output-check-cfg! out (cons (string-copy line 23) (build-script-output-check-cfg out))))
-      ((string-prefix? "cargo::rustc-env=" line)
-       (let* ((kv (string-copy line 17))
-              (splat-start (string-contains kv "=")))
-        (set-build-script-output-env! out
-          (cons
-            (cons (string-copy kv 0 splat-start) (string-copy kv (+ splat-start 1)))
-            (build-script-output-env out)))))
-      ((string-prefix? "cargo::metadata=" line)
-       (let* ((kv (string-copy line 16))
-              (splat-start (string-contains kv "=")))
-        (set-build-script-output-metadata! out
-          (cons
-            (cons (string-copy kv 0 splat-start) (string-copy kv (+ splat-start 1)))
-            (build-script-output-metadata out)))))
-      ((string-prefix? "cargo::rustc-link-search=" line)
-       (let* ((kv (string-copy line 25))
-              (splat-start (string-contains kv "=")))
-        (set-build-script-output-link-search! out
-          (cons
-            (if splat-start (cons (string-copy kv 0 splat-start) (string-copy kv (+ splat-start 1)))
-                            kv)
-            (build-script-output-link-search out)))))
-      ((string-prefix? "cargo::rustc-link-lib=" line)
-       (set-build-script-output-link-lib! out
-         (cons
-           (string-copy line 22)
-           (build-script-output-link-lib out))))
-      
-      ; TODO(puck): bad
-      ((string-prefix? "cargo::" line)
-       (let* ((kv (string-copy line 7))
-              (splat-start (string-contains kv "=")))
-        (set-build-script-output-metadata! out
-          (cons
-            (cons (string-copy kv 0 splat-start) (string-copy kv (+ splat-start 1)))
-            (build-script-output-metadata out)))))))
-     ;; TODO: link-arg-*, warning, others?
-
-   (define (parse-build-script-output port)
-     (define out (make-build-script-output '() '() '() '() '() '() '() '() '() '() '()))
-     (define (tick)
-       (define line (read-line port))
-       (if (eof-object? line)
-         out
-         (begin (parse-build-script-line line out) (tick))))
-     (tick))
-
    (define (call-runner input-script cwd env)
-     (define output (store-path-for-ca-drv* "build.rs-run" "x86_64-linux" #~(#$runner-runner) #~(("script" . #$input-script) ("cwd" . #$cwd) ("OUT_DIR" . ,(make-placeholder "outdir")) . #$env) '("out" "outdir")))
+     (define output (store-path-for-ca-drv* "build.rs-run" "x86_64-linux"
-     (values (call-with-port (store-path-open (cdr (assoc "out" output))) parse-build-script-output) (cdr (assoc "outdir" output))))))
+                      `(,runner-runner)
+                      #~(("script" . #$input-script)
+                         ("cwd" . #$cwd)
+                         ("OUT_DIR" . ,(make-placeholder "outdir"))
+                         . #$env)
+                      '("out" "outdir")))
+     (values (cdr (assoc "outdir" output)) (cdr (assoc "out" output))))))
 

lang/rust/src/resolver.sld

@@ -16,7 +16,7 @@
   <resolved-package-build-data> make-resolved-package-build-data resolved-package-build-data?
   resolved-package-build-data-dep-info resolved-package-build-data-metadata resolved-package-build-data-rlib
   resolved-package-build-data-transitive-dependencies
-  
+
   <resolved-package> make-resolved-package resolved-package?
   resolved-package-name resolved-package-version resolved-package-fs
   resolved-package-cargo-target resolved-package-enabled-features resolved-package-dependencies
@@ -38,12 +38,23 @@
    (define linker (delay #~,(string-append #$(force gcc) "/bin/cc")))
   
    (define pkgconfig (delay (cdr (assoc "out" (nixpkgs "pkg-config")))))
+   (define protobuf (delay (cdr (assoc "out" (nixpkgs "protobuf")))))
+   (define magic (delay (cdr (assoc "out" (nixpkgs "file")))))
    (define openssl (delay (let ((data (nixpkgs "openssl"))) #~,(begin #$(cdr (assoc "out" data)) #$(cdr (assoc "dev" data))))))
+   (define tvix-protos (delay (vfs-to-store (vfs-from-directory "/home/nix/store/dkjgsrg8knn406qh86c3mbxpbz2rjwfy-tvix-all-protos"))))
 
    (define (build-script-env-overrides-for-crate crate-name)
      (cond
       ((string=? crate-name "openssl-sys")
        #~(("PATH" . ,(string-append #$(force pkgconfig) "/bin:" #$(force gcc) "/bin")) ("PKG_CONFIG_PATH" . ,(string-append #$(force openssl) "/lib/pkgconfig"))))
+      ((or (string=? crate-name "ring") (string=? crate-name "bzip2-sys") (string=? crate-name "zstd-sys") (string=? crate-name "lzma-sys") (string=? crate-name "libmimalloc-sys"))
+       #~(("PATH" . ,(string-append #$(force gcc) "/bin"))))
+      ((or (string=? crate-name "tvix-castore") (string=? crate-name "tvix-store") (string=? crate-name "tvix-build"))
+       #~(("PATH" . ,(string-append #$(force protobuf) "/bin")) ("PROTO_ROOT" . #$(force tvix-protos))))
+      ((or (string=? crate-name "prost-wkt-types") (string=? crate-name "nar-bridge"))
+       #~(("PATH" . ,(string-append #$(force protobuf) "/bin"))))
+      ((or (string=? crate-name "magic-sys"))
+       #~(("NIX_LDFLAGS" . ,(string-append #$(force magic) "/lib"))))
       (else '())))
   
   
@@ -57,14 +68,15 @@
      (selected-dependencies resolver-selected-dependencies set-resolver-selected-dependencies!))
   
    (define-record-type <resolved-package-build-data>
-     (make-resolved-package-build-data dep-info metadata rlib transitive-dependencies build-script-metadata bin-flags)
+     (make-resolved-package-build-data dep-info metadata rlib transitive-dependencies build-script-metadata bin-flags build-script-out)
      resolved-package-build-data?
      (dep-info resolved-package-build-data-dep-info set-resolved-package-build-data-dep-info!)
      (metadata resolved-package-build-data-metadata set-resolved-package-build-data-metadata!)
      (rlib resolved-package-build-data-rlib set-resolved-package-build-data-rlib!)
      (transitive-dependencies resolved-package-build-data-transitive-dependencies set-resolved-package-build-data-transitive-dependencies!)
      (build-script-metadata resolved-package-build-data-build-script-metadata)
-     (bin-flags resolved-package-build-data-bin-flags))
+     (bin-flags resolved-package-build-data-bin-flags)
+     (build-script-out resolved-package-build-data-build-script-out))
   
    (define-record-type <resolved-package>
       (make-resolved-package name version fs cargo-target target-dependencies crate enabled-features dependencies build-data build-script)
@@ -291,6 +303,8 @@
      (when (list? crate-type)
        (set! crate-type 'rlib))
      (define buildscript-metadata '())
+     (define buildscript-out #f)
+     (define crate-links '())
      (define dependency-metadata '())
      (define bin-flags '())
 
@@ -327,7 +341,7 @@
           ("CARGO_PKG_RUST_VERSION" . "")
           ("CARGO_PKG_README" . "")
           ("CARGO_CRATE_NAME" . ,crate-name)))
-          ; CARGO_BIN_NAME, OUT_DIR, CARGO_BIN_EXE_*: skipping for now
+          ; CARGO_BIN_NAME, CARGO_BIN_EXE_*: skipping for now
           ; CARGO_PRIMARY_PACKAGE: not sensible here
           ; CARGO_TARGET_TMPDIR: integration/benchmark only
           ; CARGO_RUSTC_CURRENT_DIR: nightly only
@@ -348,23 +362,28 @@
         (else out)))
 
      (when (resolved-package-build-script resolved)
+       ;; "build" here is a misnomer; it's handling the .drv:s.
        (unless (resolved-package-build-data (resolved-package-build-script resolved))
          (build-package (resolved-package-build-script resolved)))
+
+       ; For each package dependency, check if it has "links" metadata.
+       ; Crate that immediately depend on other crates that have this metadata have
+       ; the cargo::metadata pairs passed to the build script.
        (mapping-for-each
          (lambda (key value)
            (unless (resolved-package-build-data value)
              (build-package value))
            (when (cargo-crate-links (resolved-package-crate value))
-             (for-each
+             ; Track (link-name . build-data) for each crate in immediate dependencies that applies
-               (lambda (kv)
+             (set! crate-links (cons (cons (cargo-crate-links (resolved-package-crate value)) (resolved-package-build-data value)) crate-links))))
-                 (set! dependency-metadata (cons (cons (string-map upcase-underscore (string-append "DEP_" (cargo-crate-links (resolved-package-crate value)) "_" (car kv))) (cdr kv)) dependency-metadata)))
-               (resolved-package-build-data-build-script-metadata (resolved-package-build-data value)))))
          (resolved-package-dependencies resolved))
+
+       ; Collect the necessary bits, and build the build script.
        (let*-values
          (((build-script) (cdr (resolved-package-build-data-rlib (resolved-package-build-data (resolved-package-build-script resolved)))))
           ((build-script-env) (build-script-env-overrides-for-crate (cargo-crate-name (resolved-package-crate resolved))))
           ((rewritten-features) (map (lambda (feature) (cons (string-map upcase-underscore (string-append "CARGO_FEATURE_" feature)) "")) (resolved-package-enabled-features resolved)))
-          ((runner-output runner-outdir)
+          ((runner-outdir runner-outpath)
            (call-runner build-script crate-root
              #~(
                 ("RUSTC" . ,(string-append #$rustc "/bin/rustc"))
@@ -373,40 +392,21 @@
                 ("OPT_LEVEL" . "0")
                 ("PROFILE" . "debug")
                 ("DEBUG" . "true")
+                ("_zilch_links" . ,(string-join #$(map (lambda (kv) #~,(string-append #$(resolved-package-build-data-build-script-out (cdr kv)) ":" (car kv))) crate-links) "!"))
                 ,@(make-cfg-values-env cfg-values '())
                 ,@dependency-metadata
                 ,@rewritten-features
                 #$@build-script-env
-                ; TODO: OUT_DIR, NUM_JOBS, OPT_LEVEL/DEBUG/PROFILE, DEP_*
+                ; TODO: OUT_DIR, NUM_JOBS, OPT_LEVEL/DEBUG/PROFILE
                 ; RUSTC/RUSTDOC?, RUSTC_LINKER? and CARGO_ENCODED_RUSTFLAGS
                 . #$rustc-env))))
-         (map
+         ; Pass the buildscript-out data to the next crate.
-           (lambda (v)
+         (set! buildscript-out runner-outpath)
-             (if (pair? v)
+
-               (set! params `(#:cfg ,(string-append (car v) "=\"" (cdr v) "\"") . ,params))
+         ; Pass cargo::rustc-cfg and cargo::rustc-check-cfg to the crate this build script belongs to.
-               (set! params `(#:cfg ,v . ,params))))
+         ; Also set OUT_DIR for include! and include_str! reasons.
-           (build-script-output-cfg runner-output))
-         (set! buildscript-metadata (build-script-output-metadata runner-output))
-         (for-each (lambda (kv) (set! rustc-env (cons kv rustc-env))) (build-script-output-env runner-output))
          (let ((old-rustc-env rustc-env))
-           (set! rustc-env #~(("OUT_DIR" . #$runner-outdir) . #$old-rustc-env)))
+           (set! rustc-env #~(("OUT_DIR" . #$runner-outdir) ("_zilch_proc" . #$runner-outpath) . #$old-rustc-env)))))
-         (for-each
-           (lambda (kv) (set! bin-flags `(#:link ,kv . ,bin-flags)))
-           (build-script-output-link-lib runner-output))
-           
-         ; TODO(puck): hack to workaround lack of store path passthrough
-         ; This should be replaced with .... $something (a dir of all build script outputs?)
-         (unless (or (null? build-script-env) (null? bin-flags))
-           (let ((v (cadr bin-flags)))
-             (set-cdr! bin-flags (cons #~,(begin #$build-script-env #$runner-outdir v) (cddr bin-flags)))))
-         (for-each
-           (lambda (kv) (set! bin-flags `(#:search-path ,kv . ,bin-flags)))
-           (build-script-output-link-search runner-output))))
-         ; TODO(puck): check-cfg wants check-cfg everywhere
-         ;(map
-         ;  (lambda (v)
-         ;    (set! params `(#:check-cfg ,v . ,params)))
-         ;  (build-script-output-check-cfg runner-output))))
 
      (define params-meta params)
      (define transitive-dependencies '())
@@ -443,8 +443,25 @@
                        (car rlib)
                        (zsymlink (cdr rlib)))) transitive-dependencies)))
 
+     (define all-crate-features '())
+     (for-each
+       (lambda (feat)
+         (set! all-crate-features
+           (cons
+             (string-append "\"" (car feat) "\"")
+             all-crate-features)))
+       (cargo-crate-features (resolved-package-crate resolved)))
+
+     (set! params `(check-cfg: ,(string-append "cfg(feature, values(" (string-join all-crate-features ",") "))") . ,params))
+
+     (define inherited-build-script-out '())
      (define transitive-bin-flags '())
-     (for-each (lambda (dep) (set! transitive-bin-flags (append (resolved-package-build-data-bin-flags (resolved-package-build-data dep)) transitive-bin-flags))) transitive-dependencies)
+     (for-each
+       (lambda (dep)
+         (set! transitive-bin-flags (append (resolved-package-build-data-bin-flags (resolved-package-build-data dep)) transitive-bin-flags))
+         (when (resolved-package-build-data-build-script-out (resolved-package-build-data dep))
+           (set! inherited-build-script-out (cons (resolved-package-build-data-build-script-out (resolved-package-build-data dep)) inherited-build-script-out))))
+       transitive-dependencies)
 
      (unless (eq? crate-type 'rlib)
        (set! params `(codegen-flags: ("linker" . ,(force linker)) . ,params)))
@@ -460,10 +477,12 @@
      (when (eq? crate-type 'bin)
        (set! rlib-name crate-name))
 
-     (when (or (eq? crate-type 'proc-macro) (eq? crate-type 'bin))
+     ; (when (or (eq? crate-type 'proc-macro) (eq? crate-type 'bin))
-       (set! params (append transitive-bin-flags params)))
+     ;   (set! params (append transitive-bin-flags params)))
      (when (eq? crate-type 'bin)
-       (set! params `(#:codegen-flags ("rpath" . "no") . ,params)))
+       (set! params `(#:codegen-flags ("rpath" . "no")  . ,params))
+       (when (string=? crate-name "tvix_cli")
+         (set! params `(search-path: ("native" . ,#~,(string-append #$(force magic) "/lib")) . ,params))))
      
      ; Rust is nitpicky about the filenames, fix them with copious symlinking.
      (define rlib-file (cdar (apply call-rustc `(,path ,rustc-env search-path: ("dependency" . ,transitive-dependencies-rlib) emits: (link: #t) ,@bin-flags . ,params))))
@@ -477,7 +496,7 @@
        (set! metadata (cons rmeta-name #~,(string-append #$(zdir rmeta-name (zsymlink metadata-file)) "/" rmeta-name)))
        (store-path-materialize metadata-file))
        
-     (set-resolved-package-build-data! resolved (make-resolved-package-build-data dep-info metadata rlib transitive-dependencies buildscript-metadata bin-flags))
+     (set-resolved-package-build-data! resolved (make-resolved-package-build-data dep-info metadata rlib transitive-dependencies buildscript-metadata bin-flags buildscript-out))
      rlib-file)
 
    (define (matches-requirements ver req)

lang/rust/src/rust.sld

@@ -11,6 +11,9 @@
 
  (begin
    (define rustc (cdr (assoc "out" (nixpkgs "rustc"))))
+   (define gcc (delay (cdr (assoc "out" (nixpkgs "gcc")))))
+   (define linker (delay #~,(string-append #$(force gcc) "/bin/cc")))
+
    (define-record-type <rustc-emits>
      (make-rustc-emits asm llvm-bc llvm-ir obj metadata link dep-info mir)
      rustc-emits?
@@ -87,6 +90,10 @@
        ((#:remap-path-prefix) (set-rustc-params-remap-path-prefix! out (cons (cadr items) (rustc-params-remap-path-prefix out))) (parse-rustc-params out (cddr items)))
        (else (error "unknown rustc param" (car items))))))
   
+  (foreign-declare "#include \"rustc_wrap_source.h\"")
+  (define rustc_wrap-bin
+    #f)
+
   (define (call-rustc input env . params)
     (call-rustc-internal input env (parse-rustc-params (make-rustc-params '() '() '() '() #f #f #f #f '() '() '()) params)))
 
@@ -136,5 +143,16 @@
         (lambda (k)
           (set! args (cons "--remap-path-prefix" (cons #~,(string-append #$(car k) "=" #$(cdr k)) args))))
         (rustc-params-remap-path-prefix params)))
-    (store-path-for-ca-drv* (string-append "rustc-" (symbol->string (rustc-params-crate-type params)) "-" (rustc-params-crate-name params)) "x86_64-linux" #~(,(string-append #$rustc "/bin/rustc") . #$args) env outputs))))
+    (if rustc_wrap-bin
+      (store-path-for-ca-drv* (string-append "rustc-" (symbol->string (rustc-params-crate-type params)) "-" (rustc-params-crate-name params)) "x86_64-linux" #~(#$rustc_wrap-bin . #$args) #~(("_zilch_rustc" . ,(string-append #$rustc "/bin/rustc")) . #$env) outputs)
+      (store-path-for-ca-drv* (string-append "rustc-" (symbol->string (rustc-params-crate-type params)) "-" (rustc-params-crate-name params)) "x86_64-linux" #~(,(string-append #$rustc "/bin/rustc") . #$args) env outputs)))
 
+  (set! rustc_wrap-bin
+    (cdar
+      (call-rustc
+        (zfile (foreign-value "rustc_wrap_source" nonnull-c-string)) '()
+        #:codegen-flags (cons "linker" (force linker))
+        #:crate-type 'bin
+        #:crate-name "rustc_wrap"
+        #:edition "2021"
+        #:emits '(#:link #t))))))