Enable SPIR-V compiler optimization (#4402)

Summary:
Pull Request resolved: #4402

Call the SPIR-V compiler with the `-O` flag, which enables optimizations when compiling GLSL to SPIR-V. The `-Os` flag (which tries to minimize SPIR-V size) was tested as well, but resulted in (very) slightly worse performance.

Reviewed By: jorgep31415

Differential Revision: D60193514

fbshipit-source-id: 2dfb999fb1951a63a990773ab563a1a3a3c304b0

backends/vulkan/runtime/gen_vulkan_spv.py

@@ -482,6 +482,7 @@ def __init__(
         src_dir_paths: Union[str, List[str]],
         env: Dict[Any, Any],
         glslc_path: Optional[str],
+        glslc_flags: str = "",
     ) -> None:
         if isinstance(src_dir_paths, str):
             self.src_dir_paths = [src_dir_paths]
@@ -490,6 +491,7 @@ def __init__(
 
         self.env = env
         self.glslc_path = glslc_path
+        self.glslc_flags = glslc_flags
 
         self.glsl_src_files: Dict[str, str] = {}
         self.template_yaml_files: List[str] = []
@@ -668,19 +670,23 @@ def process_shader(shader_paths_pair):
             if self.glslc_path is not None:
                 spv_out_path = os.path.join(output_dir, f"{shader_name}.spv")
 
-                cmd = [
-                    self.glslc_path,
-                    "-fshader-stage=compute",
-                    glsl_out_path,
-                    "-o",
-                    spv_out_path,
-                    "--target-env=vulkan1.1",
-                    "-Werror",
-                ] + [
-                    arg
-                    for src_dir_path in self.src_dir_paths
-                    for arg in ["-I", src_dir_path]
-                ]
+                cmd = (
+                    [
+                        self.glslc_path,
+                        "-fshader-stage=compute",
+                        glsl_out_path,
+                        "-o",
+                        spv_out_path,
+                        "--target-env=vulkan1.1",
+                        "-Werror",
+                    ]
+                    + [
+                        arg
+                        for src_dir_path in self.src_dir_paths
+                        for arg in ["-I", src_dir_path]
+                    ]
+                    + self.glslc_flags.split()
+                )
 
                 subprocess.check_call(cmd)
 
@@ -966,6 +972,8 @@ def main(argv: List[str]) -> int:
     parser.add_argument("-c", "--glslc-path", required=True, help="")
     parser.add_argument("-t", "--tmp-dir-path", required=True, help="/tmp")
     parser.add_argument("-o", "--output-path", required=True, help="")
+    parser.add_argument("--optimize_size", action="store_true", help="")
+    parser.add_argument("--optimize", action="store_true", help="")
     parser.add_argument(
         "--env", metavar="KEY=VALUE", nargs="*", help="Set a number of key-value pairs"
     )
@@ -984,7 +992,15 @@ def main(argv: List[str]) -> int:
     if not os.path.exists(options.tmp_dir_path):
         os.makedirs(options.tmp_dir_path)
 
-    shader_generator = SPVGenerator(options.glsl_paths, env, options.glslc_path)
+    glslc_flags = ""
+    if options.optimize_size:
+        glslc_flags += "-Os"
+    elif options.optimize:
+        glslc_flags += "-O"
+
+    shader_generator = SPVGenerator(
+        options.glsl_paths, env, options.glslc_path, glslc_flags
+    )
     output_spv_files = shader_generator.generateSPV(options.tmp_dir_path)
 
     genCppFiles(

backends/vulkan/targets.bzl

@@ -1,12 +1,15 @@
+load("@fbcode_macros//build_defs:native_rules.bzl", "buck_genrule")
 load("@fbsource//xplat/executorch/build:runtime_wrapper.bzl", "runtime")
 
 def get_vulkan_compiler_flags():
     return ["-Wno-missing-prototypes", "-Wno-global-constructors"]
 
 def vulkan_spv_shader_lib(name, spv_filegroups, is_fbcode = False):
-    gen_vulkan_spv_target = "//executorch/backends/vulkan:gen_vulkan_spv_bin"
-    glslc_path = "//caffe2/fb/vulkan/dotslash:glslc"
+    gen_vulkan_spv_target = "//xplat/executorch/backends/vulkan:gen_vulkan_spv_bin"
+    glslc_path = "//xplat/caffe2/fb/vulkan/dotslash:glslc"
+
     if is_fbcode:
+        gen_vulkan_spv_target = "//executorch/backends/vulkan:gen_vulkan_spv_bin"
         glslc_path = "//caffe2/fb/vulkan/tools:glslc"
 
     glsl_paths = []
@@ -15,21 +18,25 @@ def vulkan_spv_shader_lib(name, spv_filegroups, is_fbcode = False):
     for target, subpath in spv_filegroups.items():
         glsl_paths.append("$(location {})/{}".format(target, subpath))
 
-    genrule_cmd = [
-        "$(exe {})".format(gen_vulkan_spv_target),
-        "--glsl-paths {}".format(" ".join(glsl_paths)),
-        "--output-path $OUT",
-        "--glslc-path=$(exe {})".format(glslc_path),
-        "--tmp-dir-path=$OUT",
-    ]
+    genrule_cmd = (
+        "$(exe {}) ".format(gen_vulkan_spv_target) +
+        "--glsl-paths {} ".format(" ".join(glsl_paths)) +
+        "--output-path $OUT " +
+        "--glslc-path=$(exe {}) ".format(glslc_path) +
+        "--tmp-dir-path=$OUT " +
+        select({
+            "DEFAULT": "",
+            "ovr_config//os:android": "--optimize",
+        })
+    )
 
     genrule_name = "gen_{}_cpp".format(name)
-    runtime.genrule(
+    buck_genrule(
         name = genrule_name,
         outs = {
             "{}.cpp".format(name): ["spv.cpp"],
         },
-        cmd = " ".join(genrule_cmd),
+        cmd = genrule_cmd,
         default_outs = ["."],
         labels = ["uses_dotslash"],
     )