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

3 files changed, 48 insertions, 14 deletions

diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index fd4d9845c89..e67fe6c88ea 100644
--- a/src/librustdoc/config.rs
+++ b/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)
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index 757a2a6e0dd..679921c3269 100644
--- a/src/librustdoc/core.rs
+++ b/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,
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 1f2f8f7d33a..c1e6d324d5a 100644
--- a/src/librustdoc/lib.rs
+++ b/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;
             }