Show files produced by --emit foo in json artifact notifications

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -706,6 +706,26 @@ fn produce_final_output_artifacts(
         }
     }
 
+    if sess.opts.json_artifact_notifications {
+        if compiled_modules.modules.len() == 1 {
+            compiled_modules.modules[0].traverse_artifacts_with(|_path, descr, ty| {
+                if sess.opts.output_types.contains_key(&ty) {
+                    let path = crate_output.path(ty);
+
+                    sess.dcx().emit_artifact_notification(path.as_path(), descr);
+                }
+            });
+        } else {
+            for module in &compiled_modules.modules {
+                module.traverse_artifacts_with(|path, descr, ty| {
+                    if sess.opts.output_types.contains_key(&ty) {
+                        sess.dcx().emit_artifact_notification(&path, descr);
+                    }
+                });
+            }
+        }
+    }
+
     // We leave the following files around by default:
     //  - #crate#.o
     //  - #crate#.crate.metadata.o

compiler/rustc_codegen_ssa/src/lib.rs

@@ -115,6 +115,26 @@ pub struct CompiledModule {
     pub llvm_ir: Option<PathBuf>, // --emit=llvm-ir, llvm-bc is in bytecode
 }
 
+impl CompiledModule {
+    pub fn traverse_artifacts_with<F>(&self, mut emit: F)
+    where
+        F: FnMut(&Path, &str, OutputType),
+    {
+        if let Some(path) = self.object.as_deref() {
+            emit(path, "obj", OutputType::Object);
+        }
+        if let Some(path) = self.bytecode.as_deref() {
+            emit(path, "llvm-bc", OutputType::Bitcode);
+        }
+        if let Some(path) = self.llvm_ir.as_deref() {
+            emit(path, "llvm-ir", OutputType::LlvmAssembly);
+        }
+        if let Some(path) = self.assembly.as_deref() {
+            emit(path, "asm", OutputType::Assembly);
+        }
+    }
+}
+
 pub struct CachedModuleCodegen {
     pub name: String,
     pub source: WorkProduct,

compiler/rustc_mir_transform/src/dump_mir.rs

@@ -28,6 +28,9 @@ pub fn emit_mir(tcx: TyCtxt<'_>) -> io::Result<()> {
         OutFileName::Real(path) => {
             let mut f = io::BufWriter::new(File::create(&path)?);
             write_mir_pretty(tcx, None, &mut f)?;
+            if tcx.sess.opts.json_artifact_notifications {
+                tcx.dcx().emit_artifact_notification(&path, "mir");
+            }
         }
     }
     Ok(())

src/doc/rustc/src/json.md

@@ -217,7 +217,8 @@ Diagnostics have the following format:
 Artifact notifications are emitted when the [`--json=artifacts`
 flag][option-json] is used. They indicate that a file artifact has been saved
 to disk. More information about emit kinds may be found in the [`--emit`
-flag][option-emit] documentation.
+flag][option-emit] documentation. Notifications can contain more than one file
+for each type, for example when using multiple codegen units.
 
 ```javascript
 {
@@ -229,6 +230,11 @@ flag][option-emit] documentation.
        - "link": The generated crate as specified by the crate-type.
        - "dep-info": The `.d` file with dependency information in a Makefile-like syntax.
        - "metadata": The Rust `.rmeta` file containing metadata about the crate.
+       - "asm": The `.s` file with generated assembly
+       - "llvm-ir": The `.ll` file with generated textual LLVM IR
+       - "llvm-bc": The `.bc` file with generated LLVM bitcode
+       - "mir": The `.mir` file with rustc's mid-level intermediate representation.
+       - "obj": The `.o` file with generated native object code
     */
     "emit": "link"
 }