1 files changed, 205 insertions, 0 deletions
diff --git a/gfx/wr/swgl/build.rs b/gfx/wr/swgl/build.rs
new file mode 100644
index 0000000000..d02797d437
--- /dev/null
+++ b/gfx/wr/swgl/build.rs
@@ -0,0 +1,205 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate cc;
+extern crate glsl_to_cxx;
+extern crate webrender_build;
+
+use std::collections::HashSet;
+use std::fmt::Write;
+use webrender_build::shader::{ShaderFeatureFlags, get_shader_features};
+
+// Shader key is in "name feature,feature" format.
+// File name needs to be formatted as "name_feature_feature".
+fn shader_file(shader_key: &str) -> String {
+    shader_key.replace(' ', "_").replace(',', "_")
+}
+
+fn write_load_shader(shader_keys: &[String]) {
+    let mut load_shader = String::new();
+    for s in shader_keys {
+        let _ = write!(load_shader, "#include \"{}.h\"\n", shader_file(s));
+    }
+    load_shader.push_str("ProgramLoader load_shader(const char* name) {\n");
+    for s in shader_keys {
+        let _ = write!(load_shader, "  if (!strcmp(name, \"{}\")) {{ return {}_program::loader; }}\n",
+                       s, shader_file(s));
+    }
+    load_shader.push_str("  return nullptr;\n}\n");
+    std::fs::write(std::env::var("OUT_DIR").unwrap() + "/load_shader.h", load_shader).unwrap();
+}
+
+fn process_imports(shader_dir: &str, shader: &str, included: &mut HashSet<String>, output: &mut String) {
+    if !included.insert(shader.into()) {
+        return;
+    }
+    println!("cargo:rerun-if-changed={}/{}.glsl", shader_dir, shader);
+    let source = std::fs::read_to_string(format!("{}/{}.glsl", shader_dir, shader)).unwrap();
+    for line in source.lines() {
+        if line.starts_with("#include ") {
+            let imports = line["#include ".len() ..].split(',');
+            for import in imports {
+                process_imports(shader_dir, import, included, output);
+            }
+        } else if line.starts_with("#version ") || line.starts_with("#extension ") {
+            // ignore
+        } else {
+            output.push_str(line);
+            output.push('\n');
+        }
+    }
+}
+
+fn translate_shader(shader_key: &str, shader_dir: &str) {
+    let mut imported = String::from("#define SWGL 1\n#define __VERSION__ 150\n");
+    let _ = write!(imported, "#define WR_MAX_VERTEX_TEXTURE_WIDTH {}U\n",
+                   webrender_build::MAX_VERTEX_TEXTURE_WIDTH);
+
+    let (basename, features) =
+        shader_key.split_at(shader_key.find(' ').unwrap_or(shader_key.len()));
+    if !features.is_empty() {
+        for feature in features.trim().split(',') {
+            let _ = write!(imported, "#define WR_FEATURE_{}\n", feature);
+        }
+    }
+
+    process_imports(shader_dir, basename, &mut HashSet::new(), &mut imported);
+
+    let shader = shader_file(shader_key);
+
+    let out_dir = std::env::var("OUT_DIR").unwrap();
+    let imp_name = format!("{}/{}.c", out_dir, shader);
+    std::fs::write(&imp_name, imported).unwrap();
+
+    let mut build = cc::Build::new();
+    build.no_default_flags(true);
+    if let Ok(tool) = build.try_get_compiler() {
+        if tool.is_like_msvc() {
+            build.flag("/EP");
+            if tool.path().to_str().map_or(false, |p| p.contains("clang")) {
+                build.flag("/clang:-undef");
+            } else {
+                build.flag("/u");
+            }
+        } else {
+            build.flag("-xc").flag("-P").flag("-undef");
+        }
+    }
+    // Use SWGLPP target to avoid pulling CFLAGS/CXXFLAGS.
+    build.target("SWGLPP");
+    build.file(&imp_name);
+    let vs = build.clone()
+        .define("WR_VERTEX_SHADER", Some("1"))
+        .expand();
+    let fs = build.clone()
+        .define("WR_FRAGMENT_SHADER", Some("1"))
+        .expand();
+    let vs_name = format!("{}/{}.vert", out_dir, shader);
+    let fs_name = format!("{}/{}.frag", out_dir, shader);
+    std::fs::write(&vs_name, vs).unwrap();
+    std::fs::write(&fs_name, fs).unwrap();
+
+    let args = vec![
+        "glsl_to_cxx".to_string(),
+        vs_name,
+        fs_name,
+    ];
+    let result = glsl_to_cxx::translate(&mut args.into_iter());
+    std::fs::write(format!("{}/{}.h", out_dir, shader), result).unwrap();
+}
+
+fn main() {
+    let shader_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap() + "/../webrender/res";
+
+    let shader_flags =
+        ShaderFeatureFlags::GL |
+        ShaderFeatureFlags::DUAL_SOURCE_BLENDING |
+        ShaderFeatureFlags::ADVANCED_BLEND_EQUATION |
+        ShaderFeatureFlags::DEBUG;
+    let mut shaders: Vec<String> = Vec::new();
+    for (name, features) in get_shader_features(shader_flags) {
+        shaders.extend(features.iter().map(|f| {
+            if f.is_empty() { name.to_owned() } else { format!("{} {}", name, f) }
+        }));
+    }
+
+    shaders.sort();
+
+    // We need to ensure that the C preprocessor does not pull compiler flags from
+    // the host or target environment. Set up a SWGLPP target with empty flags to
+    // work around this.
+    if let Ok(target) = std::env::var("TARGET") {
+        if let Ok(cc) = std::env::var(format!("CC_{}", target))
+                        .or(std::env::var(format!("CC_{}", target.replace("-", "_")))) {
+            std::env::set_var("CC_SWGLPP", cc);
+        }
+    }
+    std::env::set_var("CFLAGS_SWGLPP", "");
+
+    for shader in &shaders {
+        translate_shader(shader, &shader_dir);
+    }
+
+    write_load_shader(&shaders);
+
+    println!("cargo:rerun-if-changed=src/blend.h");
+    println!("cargo:rerun-if-changed=src/composite.h");
+    println!("cargo:rerun-if-changed=src/gl_defs.h");
+    println!("cargo:rerun-if-changed=src/glsl.h");
+    println!("cargo:rerun-if-changed=src/program.h");
+    println!("cargo:rerun-if-changed=src/rasterize.h");
+    println!("cargo:rerun-if-changed=src/swgl_ext.h");
+    println!("cargo:rerun-if-changed=src/texture.h");
+    println!("cargo:rerun-if-changed=src/vector_type.h");
+    println!("cargo:rerun-if-changed=src/gl.cc");
+    let mut build = cc::Build::new();
+    build.cpp(true);
+
+    if let Ok(tool) = build.try_get_compiler() {
+        if tool.is_like_msvc() {
+            build.flag("/std:c++17")
+                 .flag("/EHs-")
+                 .flag("/GR-")
+                 .flag("/UMOZILLA_CONFIG_H");
+        } else {
+            build.flag("-std=c++17")
+                 .flag("-fno-exceptions")
+                 .flag("-fno-rtti")
+                 .flag("-fno-math-errno")
+                 .flag("-UMOZILLA_CONFIG_H");
+        }
+        // SWGL relies heavily on inlining for performance so override -Oz with -O2
+        if tool.args().contains(&"-Oz".into()) {
+            build.flag("-O2");
+        }
+
+        // Most GLSL compilers assume something like fast-math so we turn it on.
+        // However, reciprocal division makes it so 1/1 = 0.999994 which can produce a lot of fuzz
+        // in reftests and the use of reciprocal instructions usually involves a refinement step
+        // which bloats our already bloated code. Further, our shader code is sufficiently parallel
+        // that we're more likely to be throughput bound vs latency bound. Having fewer
+        // instructions makes things easier on the processor and in places where it matters we can
+        // probably explicitly use reciprocal instructions and avoid the refinement step.
+        // Also, allow checks for non-finite values which fast-math may disable.
+        if tool.is_like_msvc() {
+            build.flag("/fp:fast")
+                 .flag("-Xclang")
+                 .flag("-mrecip=none")
+                 .flag("/clang:-fno-finite-math-only");
+        } else if tool.is_like_clang() {
+            // gcc only supports -mrecip=none on some targets so to keep
+            // things simple we don't use -ffast-math with gcc at all
+            build.flag("-ffast-math")
+                 .flag("-mrecip=none")
+                 .flag("-fno-finite-math-only");
+        }
+    }
+
+    build.file("src/gl.cc")
+        .define("_GLIBCXX_USE_CXX11_ABI", Some("0"))
+        .include(shader_dir)
+        .include("src")
+        .include(std::env::var("OUT_DIR").unwrap())
+        .compile("gl_cc");
+}