From e91cc685b1f87ca9661833f10b1d0822f3678ebf Mon Sep 17 00:00:00 2001
From: Henry de Valence <hdevalence@hdevalence.ca>
Date: Thu, 29 Nov 2018 10:58:05 -0800
Subject: [PATCH] Don't generate unused constants in build.rs.

---
 build.rs | 58 ++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 35 insertions(+), 23 deletions(-)

diff --git a/build.rs b/build.rs
index f24e47b..e9c2a66 100644
--- a/build.rs
+++ b/build.rs
@@ -44,33 +44,31 @@ mod macros;
 
 // Public modules
 
-#[path = "src/scalar.rs"]
-mod scalar;
-#[path = "src/montgomery.rs"]
-mod montgomery;
-#[path = "src/edwards.rs"]
-mod edwards;
-#[path = "src/ristretto.rs"]
-mod ristretto;
 #[path = "src/constants.rs"]
 mod constants;
+#[path = "src/edwards.rs"]
+mod edwards;
+#[path = "src/montgomery.rs"]
+mod montgomery;
+#[path = "src/ristretto.rs"]
+mod ristretto;
+#[path = "src/scalar.rs"]
+mod scalar;
 #[path = "src/traits.rs"]
 mod traits;
 
 // Internal modules
 
-#[path = "src/field.rs"]
-mod field;
 #[path = "src/backend/mod.rs"]
 mod backend;
+#[path = "src/field.rs"]
+mod field;
 #[path = "src/prelude.rs"]
 mod prelude;
 #[path = "src/window.rs"]
 mod window;
 
 use edwards::EdwardsBasepointTable;
-use backend::serial::curve_models::AffineNielsPoint;
-use window::NafLookupTable8;
 
 fn main() {
     // Enable the "stage2_build" feature in the main build stage
@@ -97,7 +95,6 @@ use edwards::EdwardsBasepointTable;
 use backend::serial::curve_models::AffineNielsPoint;
 
 use window::LookupTable;
-use window::NafLookupTable8;
 
 /// Table containing precomputed multiples of the Ed25519 basepoint \\\\(B = (x, 4/5)\\\\).
 pub const ED25519_BASEPOINT_TABLE: EdwardsBasepointTable = ED25519_BASEPOINT_TABLE_INNER_DOC_HIDDEN;
@@ -107,20 +104,35 @@ pub const ED25519_BASEPOINT_TABLE: EdwardsBasepointTable = ED25519_BASEPOINT_TAB
 pub const ED25519_BASEPOINT_TABLE_INNER_DOC_HIDDEN: EdwardsBasepointTable = {:?};
 \n\n",
             &table
-        ).as_bytes(),
-    ).unwrap();
+        )
+        .as_bytes(),
+    )
+    .unwrap();
 
     // Now generate AFFINE_ODD_MULTIPLES_OF_BASEPOINT
-    let B = &constants::ED25519_BASEPOINT_POINT;
-    let odd_multiples = NafLookupTable8::<AffineNielsPoint>::from(B);
+    // if we are going to build the serial scalar_mul backend
+    #[cfg(not(all(
+        feature = "simd_backend",
+        any(target_feature = "avx2", target_feature = "avx512ifma")
+    )))]
+    {
+        use backend::serial::curve_models::AffineNielsPoint;
+        use window::NafLookupTable8;
 
-    f.write_all(
-        format!(
-            "\n
+        let B = &constants::ED25519_BASEPOINT_POINT;
+        let odd_multiples = NafLookupTable8::<AffineNielsPoint>::from(B);
+
+        f.write_all(
+            format!(
+                "\n
+use window::NafLookupTable8;
 /// Odd multiples of the basepoint `[B, 3B, 5B, 7B, 9B, 11B, 13B, 15B, ..., 127B]`.
 pub(crate) const AFFINE_ODD_MULTIPLES_OF_BASEPOINT: NafLookupTable8<AffineNielsPoint> = {:?};
 \n\n",
-            &odd_multiples
-        ).as_bytes(),
-    ).unwrap();
+                &odd_multiples
+            )
+            .as_bytes(),
+        )
+        .unwrap();
+    }
 }