Add rustdoc support for --emit=dep-info[=path]

src/librustdoc/config.rs

@@ -315,23 +315,30 @@ pub(crate) enum ModuleSorting {
     Alphabetical,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) enum EmitType {
     Unversioned,
     Toolchain,
     InvocationSpecific,
+    DepInfo(Option<PathBuf>),
 }
 
 impl FromStr for EmitType {
     type Err = ();
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        use EmitType::*;
         match s {
-            "unversioned-shared-resources" => Ok(Unversioned),
-            "toolchain-shared-resources" => Ok(Toolchain),
-            "invocation-specific" => Ok(InvocationSpecific),
-            _ => Err(()),
+            "unversioned-shared-resources" => Ok(Self::Unversioned),
+            "toolchain-shared-resources" => Ok(Self::Toolchain),
+            "invocation-specific" => Ok(Self::InvocationSpecific),
+            "dep-info" => Ok(Self::DepInfo(None)),
+            option => {
+                if let Some(file) = option.strip_prefix("dep-info=") {
+                    Ok(Self::DepInfo(Some(Path::new(file).into())))
+                } else {
+                    Err(())
+                }
+            }
         }
     }
 }
@@ -340,6 +347,15 @@ impl RenderOptions {
     pub(crate) fn should_emit_crate(&self) -> bool {
         self.emit.is_empty() || self.emit.contains(&EmitType::InvocationSpecific)
     }
+
+    pub(crate) fn dep_info(&self) -> Option<Option<&Path>> {
+        for emit in &self.emit {
+            if let EmitType::DepInfo(file) = emit {
+                return Some(file.as_deref());
+            }
+        }
+        None
+    }
 }
 
 /// Create the input (string or file path)

src/librustdoc/core.rs

@@ -15,11 +15,12 @@ use rustc_hir::def::Res;
 use rustc_hir::def_id::{DefId, DefIdMap, DefIdSet, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{HirId, Path};
-use rustc_interface::interface;
 use rustc_lint::{MissingDoc, late_lint_mod};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt};
-use rustc_session::config::{self, CrateType, ErrorOutputType, Input, ResolveDocLinks};
+use rustc_session::config::{
+    self, CrateType, ErrorOutputType, Input, OutFileName, OutputType, OutputTypes, ResolveDocLinks,
+};
 pub(crate) use rustc_session::config::{Options, UnstableOptions};
 use rustc_session::{Session, lint};
 use rustc_span::source_map;
@@ -219,7 +220,7 @@ pub(crate) fn create_config(
         remap_path_prefix,
         ..
     }: RustdocOptions,
-    RenderOptions { document_private, .. }: &RenderOptions,
+    render_options: &RenderOptions,
 ) -> rustc_interface::Config {
     // Add the doc cfg into the doc build.
     cfgs.push("doc".to_string());
@@ -245,8 +246,11 @@ pub(crate) fn create_config(
 
     let crate_types =
         if proc_macro_crate { vec![CrateType::ProcMacro] } else { vec![CrateType::Rlib] };
-    let resolve_doc_links =
-        if *document_private { ResolveDocLinks::All } else { ResolveDocLinks::Exported };
+    let resolve_doc_links = if render_options.document_private {
+        ResolveDocLinks::All
+    } else {
+        ResolveDocLinks::Exported
+    };
     let test = scrape_examples_options.map(|opts| opts.scrape_tests).unwrap_or(false);
     // plays with error output here!
     let sessopts = config::Options {
@@ -269,10 +273,18 @@ pub(crate) fn create_config(
         crate_name,
         test,
         remap_path_prefix,
+        output_types: if let Some(file) = render_options.dep_info() {
+            OutputTypes::new(&[(
+                OutputType::DepInfo,
+                file.map(|f| OutFileName::Real(f.to_path_buf())),
+            )])
+        } else {
+            OutputTypes::new(&[])
+        },
         ..Options::default()
     };
 
-    interface::Config {
+    rustc_interface::Config {
         opts: sessopts,
         crate_cfg: cfgs,
         crate_check_cfg: check_cfgs,

src/librustdoc/html/render/write_shared.rs

@@ -153,7 +153,7 @@ fn write_rendered_cross_crate_info(
     include_sources: bool,
 ) -> Result<(), Error> {
     let m = &opt.should_merge;
-    if opt.emit.is_empty() || opt.emit.contains(&EmitType::InvocationSpecific) {
+    if opt.should_emit_crate() {
         if include_sources {
             write_rendered_cci::<SourcesPart, _>(SourcesPart::blank, dst, crates, m)?;
         }

src/librustdoc/lib.rs

@@ -561,7 +561,7 @@ fn opts() -> Vec<RustcOptGroup> {
             "",
             "emit",
             "Comma separated list of types of output for rustdoc to emit",
-            "[unversioned-shared-resources,toolchain-shared-resources,invocation-specific]",
+            "[unversioned-shared-resources,toolchain-shared-resources,invocation-specific,dep-info]",
         ),
         opt(Unstable, FlagMulti, "", "no-run", "Compile doctests without running them", ""),
         opt(
@@ -890,7 +890,13 @@ fn main_args(early_dcx: &mut EarlyDiagCtxt, at_args: &[String]) {
                 // if we ran coverage, bail early, we don't need to also generate docs at this point
                 // (also we didn't load in any of the useful passes)
                 return;
-            } else if run_check {
+            }
+
+            if render_opts.dep_info().is_some() {
+                rustc_interface::passes::write_dep_info(tcx);
+            }
+
+            if run_check {
                 // Since we're in "check" mode, no need to generate anything beyond this point.
                 return;
             }

src/tools/run-make-support/src/external_deps/rustdoc.rs

@@ -132,4 +132,11 @@ impl Rustdoc {
         self.cmd.arg(format);
         self
     }
+
+    /// Specify type(s) of output files to generate.
+    pub fn emit<S: AsRef<str>>(&mut self, kinds: S) -> &mut Self {
+        let kinds = kinds.as_ref();
+        self.cmd.arg(format!("--emit={kinds}"));
+        self
+    }
 }

tests/run-make/rustdoc-default-output/output-default.stdout

@@ -153,7 +153,7 @@ Options:
         --generate-redirect-map 
                         Generate JSON file at the top level instead of
                         generating HTML redirection files
-        --emit [unversioned-shared-resources,toolchain-shared-resources,invocation-specific]
+        --emit [unversioned-shared-resources,toolchain-shared-resources,invocation-specific,dep-info]
                         Comma separated list of types of output for rustdoc to
                         emit
         --no-run        Compile doctests without running them

tests/run-make/rustdoc-dep-info/bar.rs

@@ -0,0 +1 @@
+include!("foo.rs");

tests/run-make/rustdoc-dep-info/doc.md

@@ -0,0 +1 @@
+blablabla

tests/run-make/rustdoc-dep-info/foo.rs

@@ -0,0 +1 @@
+pub fn foo() {}

tests/run-make/rustdoc-dep-info/lib.rs

@@ -0,0 +1,6 @@
+#![crate_name = "foo"]
+
+#[cfg_attr(doc, doc = include_str!("doc.md"))]
+pub struct Bar;
+
+mod bar;

tests/run-make/rustdoc-dep-info/rmake.rs

@@ -0,0 +1,21 @@
+// This is a simple smoke test for rustdoc's `--emit dep-info` feature. It prints out
+// information about dependencies in a Makefile-compatible format, as a `.d` file.
+
+use run_make_support::assertion_helpers::assert_contains;
+use run_make_support::{path, rfs, rustdoc};
+
+fn main() {
+    // We're only emitting dep info, so we shouldn't be running static analysis to
+    // figure out that this program is erroneous.
+    rustdoc().input("lib.rs").arg("-Zunstable-options").emit("dep-info").run();
+
+    let content = rfs::read_to_string("foo.d");
+    assert_contains(&content, "lib.rs:");
+    assert_contains(&content, "foo.rs:");
+    assert_contains(&content, "bar.rs:");
+    assert_contains(&content, "doc.md:");
+
+    // Now we check that we can provide a file name to the `dep-info` argument.
+    rustdoc().input("lib.rs").arg("-Zunstable-options").emit("dep-info=bla.d").run();
+    assert!(path("bla.d").exists());
+}