Add a preserve_bindings opt to the builder and codegen opts

crates/rustc_codegen_spirv/src/codegen_cx/mod.rs

@@ -251,6 +251,9 @@ pub struct CodegenArgs {
  pub uniform_buffer_standard_layout: bool,
  pub scalar_block_layout: bool,
  pub skip_block_layout: bool,
+
+ // spirv-opt flags
+ pub preserve_bindings: bool,
 }
 
 impl CodegenArgs {
@@ -289,6 +292,13 @@ impl CodegenArgs {
  opts.optflagopt("", "scalar-block-layout", "Enable VK_EXT_scalar_block_layout when checking standard uniform, storage buffer, and push constant layouts. Scalar layout rules are more permissive than relaxed block layout so in effect this will override the --relax-block-layout option.", "");
  opts.optflagopt("", "skip-block-layout", "Skip checking standard uniform/storage buffer layout. Overrides any --relax-block-layout or --scalar-block-layout option.", "");
 
+ opts.optflagopt(
+ "",
+ "preserve-bindings",
+ "Preserve unused descriptor bindings. Useful for reflection.",
+ "",
+ );
+
  let matches = opts.parse(args)?;
  let module_output_type =
  matches.opt_get_default("module-output", ModuleOutputType::Single)?;
@@ -306,6 +316,8 @@ impl CodegenArgs {
  let scalar_block_layout = matches.opt_present("scalar-block-layout");
  let skip_block_layout = matches.opt_present("skip-block-layout");
 
+ let preserve_bindings = matches.opt_present("preserve-bindings");
+
  let relax_block_layout = if relax_block_layout { Some(true) } else { None };
 
  let spirv_metadata = match spirv_metadata.as_deref() {
@@ -334,6 +346,8 @@ impl CodegenArgs {
  uniform_buffer_standard_layout,
  scalar_block_layout,
  skip_block_layout,
+
+ preserve_bindings,
  })
  }
 

crates/rustc_codegen_spirv/src/link.rs

@@ -209,7 +209,7 @@ fn post_link_single_module(
  let opt_options = spirv_tools::opt::Options {
  validator_options: Some(val_options.clone()),
  max_id_bound: None,
- preserve_bindings: false,
+ preserve_bindings: cg_args.preserve_bindings,
  preserve_spec_constants: false,
  };
 

crates/spirv-builder/src/lib.rs

@@ -166,6 +166,9 @@ pub struct SpirvBuilder {
  pub uniform_buffer_standard_layout: bool,
  pub scalar_block_layout: bool,
  pub skip_block_layout: bool,
+
+ // spirv-opt flags
+ pub preserve_bindings: bool,
 }
 
 impl SpirvBuilder {
@@ -187,6 +190,8 @@ impl SpirvBuilder {
  uniform_buffer_standard_layout: false,
  scalar_block_layout: false,
  skip_block_layout: false,
+
+ preserve_bindings: false,
  }
  }
 
@@ -278,6 +283,12 @@ impl SpirvBuilder {
  self
  }
 
+ /// Preserve unused descriptor bindings. Useful for reflection.
+ pub fn preserve_bindings(mut self, v: bool) -> Self {
+ self.preserve_bindings = v;
+ self
+ }
+
  /// Builds the module. If `print_metadata` is [`MetadataPrintout::Full`], you usually don't have to inspect the path
  /// in the result, as the environment variable for the path to the module will already be set.
  pub fn build(mut self) -> Result<CompileResult, SpirvBuilderError> {
@@ -424,6 +435,9 @@ fn invoke_rustc(builder: &SpirvBuilder) -> Result<PathBuf, SpirvBuilderError> {
  if builder.skip_block_layout {
  llvm_args.push("--skip-block-layout");
  }
+ if builder.preserve_bindings {
+ llvm_args.push("--preserve-bindings");
+ }
  let llvm_args = join_checking_for_separators(llvm_args, " ");
  if !llvm_args.is_empty() {
  rustflags.push(["-Cllvm-args=", &llvm_args].concat());