Remove --no-spirt and the old structurizer.

Author: eddyb

CHANGELOG.md

@@ -27,6 +27,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 -->
 
+## [Unreleased]
+
+### Removed 🔥
+- [PR#1052](https://github.com/EmbarkStudios/rust-gpu/pull/1052) removed `--no-spirt`,
+  committing to SPIR-T as a mandatory part of the Rust-GPU compiler backend,
+  to reduce the cost of maintenance, testing and further feature development  
+  * Note: if you were using `--no-spirt` to work around [`naga` issue #1977](https://github.com/gfx-rs/naga/issues/1977)  
+    (valid loops causing `The 'break' is used outside of a 'loop' or 'switch' context`),  
+    you may be able to `cargo update -p naga` to update to a fixed `naga` version  
+    (`0.11.1` for `wgpu 0.15`, `0.12.1` for `wgpu 0.16`, and any later versions)
+
 ## [0.7.0]
 
 ### Added ⭐

crates/rustc_codegen_spirv/src/codegen_cx/mod.rs

@@ -342,11 +342,6 @@ impl CodegenArgs {
             );
             opts.optflag("", "no-structurize", "disables CFG structurization");
 
-            opts.optflag(
-                "",
-                "no-spirt",
-                "disable using SPIR-T for legalization (see also `docs/src/codegen-args.md`)",
-            );
             opts.optmulti(
                 "",
                 "spirt-passes",
@@ -522,7 +517,6 @@ impl CodegenArgs {
             early_report_zombies: !matches.opt_present("no-early-report-zombies"),
             infer_storage_classes: !matches.opt_present("no-infer-storage-classes"),
             structurize: !matches.opt_present("no-structurize"),
-            spirt: !matches.opt_present("no-spirt"),
             spirt_passes: matches
                 .opt_strs("spirt-passes")
                 .iter()

crates/rustc_codegen_spirv/src/linker/mod.rs

@@ -14,7 +14,6 @@ mod peephole_opts;
 mod simple_passes;
 mod specializer;
 mod spirt_passes;
-mod structurizer;
 mod zombies;
 
 use std::borrow::Cow;
@@ -41,7 +40,6 @@ pub struct Options {
     pub early_report_zombies: bool,
     pub infer_storage_classes: bool,
     pub structurize: bool,
-    pub spirt: bool,
     pub spirt_passes: Vec<String>,
 
     pub emit_multiple_modules: bool,
@@ -268,7 +266,7 @@ pub fn link(
     }
 
     // NOTE(eddyb) with SPIR-T, we can do `mem2reg` before inlining, too!
-    if opts.spirt {
+    {
         if opts.dce {
             let _timer = sess.timer("link_dce-before-inlining");
             dce::dce(&mut output);
@@ -322,13 +320,6 @@ pub fn link(
         dce::dce(&mut output);
     }
 
-    let mut output = if opts.structurize && !opts.spirt {
-        let _timer = sess.timer("link_structurize");
-        structurizer::structurize(output)
-    } else {
-        output
-    };
-
     {
         let _timer = sess.timer("link_block_ordering_pass_and_mem2reg-after-inlining");
         let mut pointer_to_pointee = FxHashMap::default();
@@ -368,7 +359,8 @@ pub fn link(
         }
     }
 
-    if opts.spirt {
+    // NOTE(eddyb) SPIR-T pipeline is entirely limited to this block.
+    {
         let mut per_pass_module_for_dumping = vec![];
         let mut after_pass = |pass, module: &spirt::Module| {
             if opts.dump_spirt_passes.is_some() {
@@ -470,6 +462,11 @@ pub fn link(
         };
     }
 
+    // FIXME(eddyb) rewrite these passes to SPIR-T ones, so we don't have to
+    // parse the output of `spirt::spv::lift` back into `rspirv` - also, for
+    // multi-module, it's much simpler with SPIR-T, just replace `module.exports`
+    // with a single-entry map, run `spirt::spv::lift` (or even `spirt::print`)
+    // on `module`, then put back the full original `module.exports` map.
     {
         let _timer = sess.timer("peephole_opts");
         let types = peephole_opts::collect_types(&output);