linker: add --dump-{pre,post}-inline to be able to debug the inliner.

Author: eddyb

crates/rustc_codegen_spirv/src/codegen_cx/mod.rs

@@ -442,6 +442,18 @@ impl CodegenArgs {
                 "dump the merged module immediately after merging, to a file in DIR",
                 "DIR",
             );
+            opts.optopt(
+                "",
+                "dump-pre-inline",
+                "dump the module immediately before inlining, to a file in DIR",
+                "DIR",
+            );
+            opts.optopt(
+                "",
+                "dump-post-inline",
+                "dump the module immediately after inlining, to a file in DIR",
+                "DIR",
+            );
             opts.optopt(
                 "",
                 "dump-post-split",
@@ -620,6 +632,8 @@ impl CodegenArgs {
             // NOTE(eddyb) these are debugging options that used to be env vars
             // (for more information see `docs/src/codegen-args.md`).
             dump_post_merge: matches_opt_dump_dir_path("dump-post-merge"),
+            dump_pre_inline: matches_opt_dump_dir_path("dump-pre-inline"),
+            dump_post_inline: matches_opt_dump_dir_path("dump-post-inline"),
             dump_post_split: matches_opt_dump_dir_path("dump-post-split"),
             dump_spirt_passes: matches_opt_dump_dir_path("dump-spirt-passes"),
             spirt_strip_custom_debuginfo_from_dumps: matches

crates/rustc_codegen_spirv/src/linker/mod.rs

@@ -58,6 +58,8 @@ pub struct Options {
     // NOTE(eddyb) these are debugging options that used to be env vars
     // (for more information see `docs/src/codegen-args.md`).
     pub dump_post_merge: Option<PathBuf>,
+    pub dump_pre_inline: Option<PathBuf>,
+    pub dump_post_inline: Option<PathBuf>,
     pub dump_post_split: Option<PathBuf>,
     pub dump_spirt_passes: Option<PathBuf>,
     pub spirt_strip_custom_debuginfo_from_dumps: bool,
@@ -402,6 +404,10 @@ pub fn link(
         duplicates::remove_duplicate_debuginfo(&mut output);
     }
 
+    if let Some(dir) = &opts.dump_pre_inline {
+        dump_spv_and_spirt(&output, dir.join(disambiguated_crate_name_for_dumps));
+    }
+
     {
         let _timer = sess.timer("link_inline");
         inline::inline(sess, &mut output)?;
@@ -412,6 +418,11 @@ pub fn link(
         dce::dce(&mut output);
     }
 
+    // HACK(eddyb) this has to be after DCE, to not break SPIR-T w/ dead decorations.
+    if let Some(dir) = &opts.dump_post_inline {
+        dump_spv_and_spirt(&output, dir.join(disambiguated_crate_name_for_dumps));
+    }
+
     {
         let _timer = sess.timer("link_block_ordering_pass_and_mem2reg-after-inlining");
         let mut pointer_to_pointee = FxHashMap::default();

docs/src/codegen-args.md

@@ -79,6 +79,14 @@ Dumps the merged module, to a file in `DIR`, immediately after merging, but befo
 similar to `--dump-pre-link`, except it outputs only a single file, which might make grepping through
 for stuff easier.
 
+### `--dump-pre-inline DIR`
+
+Dumps the module, to a file in `DIR`, immediately before the inliner pass runs.
+
+### `--dump-post-inline DIR`
+
+Dumps the module, to a file in `DIR`, immediately after the inliner pass runs.
+
 ### `--dump-post-split DIR`
 
 Dumps the modules, to files in `DIR`, immediately after multimodule splitting, but before final cleanup passes (e.g.