Allow tuning rust packages

1 files changed, 22 insertions, 13 deletions

diff --git a/gn/packages/pangenome-rust.scm b/gn/packages/pangenome-rust.scm
index 966384a..91c9d6d 100644
--- a/gn/packages/pangenome-rust.scm
+++ b/gn/packages/pangenome-rust.scm
@@ -34,25 +34,34 @@
   (crate-source "anyhow" "1.0.66"
                 "1xj3ahmwjlbiqsajhkaa0q6hqwb4l3l5rkfxa7jk1498r3fn2qi1"))
 
-;; Phase snippet to set RUSTFLAGS for CPU tuning.
-;; Detects the tuning CPU from PATH (tuning-compiler-<cpu> directory)
-;; and sets RUSTFLAGS=-C target-cpu=<cpu>.
+;; Phase snippet for CPU tuning of Rust packages.
+;; Removes the tuning rustc wrapper from PATH (which injects -C target_cpu
+;; into ALL rustc calls including build scripts, causing SIGILL on
+;; cross-tuning) and instead sets CARGO_BUILD_RUSTFLAGS which only applies
+;; to target crate compilation, not build scripts.
 (define %rust-tuning-phase
   #~(add-before 'build 'set-rust-target-cpu
       (lambda _
-        (let loop ((dirs (string-split (or (getenv "PATH") "") #\:)))
+        (let loop ((dirs (string-split (or (getenv "PATH") "") #\:))
+                   (kept '())
+                   (cpu #f))
           (if (null? dirs)
-              #t
+              (begin
+                (setenv "PATH" (string-join (reverse kept) ":"))
+                (when cpu
+                  (setenv "CARGO_BUILD_RUSTFLAGS"
+                          (string-append (or (getenv "CARGO_BUILD_RUSTFLAGS") "")
+                                         " -C target-cpu=" cpu))
+                  (format #t "  Removed tuning rustc wrapper from PATH~%")
+                  (format #t "  CARGO_BUILD_RUSTFLAGS set for CPU tuning: ~a~%"
+                          (getenv "CARGO_BUILD_RUSTFLAGS"))))
               (let ((base (basename (dirname (car dirs)))))
                 (if (string-contains base "tuning-compiler-")
-                    (let ((cpu (substring base
-                                         (+ (string-contains base "tuning-compiler-")
-                                            (string-length "tuning-compiler-")))))
-                      (setenv "RUSTFLAGS"
-                              (string-append (or (getenv "RUSTFLAGS") "")
-                                             " -C target-cpu=" cpu))
-                      (format #t "  RUSTFLAGS set for CPU tuning: ~a~%" (getenv "RUSTFLAGS")))
-                    (loop (cdr dirs)))))))))
+                    (let ((detected (substring base
+                                              (+ (string-contains base "tuning-compiler-")
+                                                 (string-length "tuning-compiler-")))))
+                      (loop (cdr dirs) kept detected))
+                    (loop (cdr dirs) (cons (car dirs) kept) cpu))))))))
 
 
 (define rust-autocfg-1.1.0