build: add libghostty simd toggle for ci

2 files changed, 33 insertions, 4 deletions

diff --git a/.github/workflows/build-artifacts-manual.yml b/.github/workflows/build-artifacts-manual.yml
index c880a852..458c8209 100644
--- a/.github/workflows/build-artifacts-manual.yml
+++ b/.github/workflows/build-artifacts-manual.yml
@@ -22,6 +22,14 @@ on:
           - ReleaseFast
           - ReleaseSmall
           - Debug
+      libghostty_simd:
+        description: build libghostty-vt with SIMD-accelerated code paths
+        required: true
+        default: 'false'
+        type: choice
+        options:
+          - 'false'
+          - 'true'
 
 permissions:
   contents: read
@@ -45,6 +53,7 @@ jobs:
             name: herdr-linux-aarch64
     env:
       LIBGHOSTTY_VT_OPTIMIZE: ${{ inputs.libghostty_optimize }}
+      LIBGHOSTTY_VT_SIMD: ${{ inputs.libghostty_simd }}
 
     steps:
       - uses: actions/checkout@v4
@@ -81,13 +90,14 @@ jobs:
             echo "commit=$GITHUB_SHA"
             echo "target=${{ matrix.target }}"
             echo "libghostty_vt_optimize=$LIBGHOSTTY_VT_OPTIMIZE"
+            echo "libghostty_vt_simd=$LIBGHOSTTY_VT_SIMD"
           } >> BUILD_INFO.txt
           python3 -c "import hashlib, pathlib; artifact = pathlib.Path('${{ matrix.name }}'); print(f'sha256={hashlib.sha256(artifact.read_bytes()).hexdigest()}  {artifact.name}')" >> BUILD_INFO.txt
 
       - name: Upload artifact
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.name }}-${{ inputs.libghostty_optimize }}
+          name: ${{ matrix.name }}-${{ inputs.libghostty_optimize }}-simd-${{ inputs.libghostty_simd }}
           path: |
             ${{ matrix.name }}
             BUILD_INFO.txt
@@ -108,6 +118,7 @@ jobs:
             name: herdr-macos-aarch64
     env:
       LIBGHOSTTY_VT_OPTIMIZE: ${{ inputs.libghostty_optimize }}
+      LIBGHOSTTY_VT_SIMD: ${{ inputs.libghostty_simd }}
 
     steps:
       - uses: actions/checkout@v4
@@ -140,13 +151,14 @@ jobs:
             echo "commit=$GITHUB_SHA"
             echo "target=${{ matrix.target }}"
             echo "libghostty_vt_optimize=$LIBGHOSTTY_VT_OPTIMIZE"
+            echo "libghostty_vt_simd=$LIBGHOSTTY_VT_SIMD"
           } >> BUILD_INFO.txt
           python3 -c "import hashlib, pathlib; artifact = pathlib.Path('${{ matrix.name }}'); print(f'sha256={hashlib.sha256(artifact.read_bytes()).hexdigest()}  {artifact.name}')" >> BUILD_INFO.txt
 
       - name: Upload artifact
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.name }}-${{ inputs.libghostty_optimize }}
+          name: ${{ matrix.name }}-${{ inputs.libghostty_optimize }}-simd-${{ inputs.libghostty_simd }}
           path: |
             ${{ matrix.name }}
             BUILD_INFO.txt
diff --git a/build.rs b/build.rs
index da921cfc..dc4031c5 100644
--- a/build.rs
+++ b/build.rs
@@ -15,6 +15,18 @@ fn zig_target(target: &str) -> &str {
     }
 }
 
+fn env_bool(name: &str) -> Option<bool> {
+    match env::var(name) {
+        Ok(value) => match value.to_ascii_lowercase().as_str() {
+            "1" | "true" | "yes" | "on" => Some(true),
+            "0" | "false" | "no" | "off" => Some(false),
+            other => panic!("invalid boolean value for {name}: {other}"),
+        },
+        Err(env::VarError::NotPresent) => None,
+        Err(err) => panic!("failed to read {name}: {err}"),
+    }
+}
+
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed=vendor/libghostty-vt.vendor.json");
@@ -22,10 +34,12 @@ fn main() {
     println!("cargo:rerun-if-changed=vendor/libghostty-vt/build.zig.zon");
     println!("cargo:rerun-if-changed=vendor/libghostty-vt/VERSION");
     println!("cargo:rerun-if-env-changed=LIBGHOSTTY_VT_OPTIMIZE");
+    println!("cargo:rerun-if-env-changed=LIBGHOSTTY_VT_SIMD");
 
     let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR"));
     let vendored_dir = manifest_dir.join("vendor/libghostty-vt");
     let optimize = env::var("LIBGHOSTTY_VT_OPTIMIZE").unwrap_or_else(|_| "ReleaseFast".into());
+    let simd = env_bool("LIBGHOSTTY_VT_SIMD").unwrap_or(true);
     let target = env::var("TARGET").expect("TARGET");
     let zig_target = zig_target(&target);
     let version_string = fs::read_to_string(vendored_dir.join("VERSION"))
@@ -37,6 +51,7 @@ fn main() {
         .arg("build")
         .arg("-Demit-lib-vt")
         .arg(format!("-Doptimize={optimize}"))
+        .arg(format!("-Dsimd={simd}"))
         .arg(format!("-Dtarget={zig_target}"))
         .arg(format!("-Dversion-string={version_string}"))
         .current_dir(&vendored_dir)
@@ -52,10 +67,12 @@ fn main() {
     if target.contains("apple-darwin") {
         let static_lib = lib_dir.join("libghostty-vt.a");
         println!("cargo:rustc-link-arg={}", static_lib.display());
-        println!("cargo:rustc-link-lib=dylib=c++");
+        if simd {
+            println!("cargo:rustc-link-lib=dylib=c++");
+        }
     } else {
         println!("cargo:rustc-link-lib=static=ghostty-vt");
-        if target.contains("linux") {
+        if target.contains("linux") && simd {
             println!("cargo:rustc-link-lib=dylib=stdc++");
         }
     }