Rollup merge of rust-lang#40348 - nrc:save-extern-fn, r=eddyb

Handle extern functions and statics in save-analysis

r? @eddyb

Author: Ariel Ben-Yehuda

src/librustc_save_analysis/dump_visitor.rs

@@ -1363,15 +1363,6 @@ impl<'l, 'tcx: 'l, 'll, D: Dump +'ll> Visitor<'l> for DumpVisitor<'l, 'tcx, 'll,
         debug!("visit_expr {:?}", ex.node);
         self.process_macro_use(ex.span, ex.id);
         match ex.node {
-            ast::ExprKind::Call(ref _f, ref _args) => {
-                // Don't need to do anything for function calls,
-                // because just walking the callee path does what we want.
-                visit::walk_expr(self, ex);
-            }
-            ast::ExprKind::Path(_, ref path) => {
-                self.process_path(ex.id, path, None);
-                visit::walk_expr(self, ex);
-            }
             ast::ExprKind::Struct(ref path, ref fields, ref base) => {
                 let hir_expr = self.save_ctxt.tcx.hir.expect_expr(ex.id);
                 let adt = match self.save_ctxt.tables.expr_ty_opt(&hir_expr) {
@@ -1469,6 +1460,8 @@ impl<'l, 'tcx: 'l, 'll, D: Dump +'ll> Visitor<'l> for DumpVisitor<'l, 'tcx, 'll,
                 self.visit_expr(element);
                 self.nest_tables(count.id, |v| v.visit_expr(count));
             }
+            // In particular, we take this branch for call and path expressions,
+            // where we'll index the idents involved just by continuing to walk.
             _ => {
                 visit::walk_expr(self, ex)
             }
@@ -1567,4 +1560,39 @@ impl<'l, 'tcx: 'l, 'll, D: Dump +'ll> Visitor<'l> for DumpVisitor<'l, 'tcx, 'll,
         walk_list!(self, visit_ty, &l.ty);
         walk_list!(self, visit_expr, &l.init);
     }
+
+    fn visit_foreign_item(&mut self, item: &'l ast::ForeignItem) {
+        match item.node {
+            ast::ForeignItemKind::Fn(ref decl, ref generics) => {
+                if let Some(fn_data) = self.save_ctxt.get_extern_item_data(item) {
+                    down_cast_data!(fn_data, FunctionData, item.span);
+                    if !self.span.filter_generated(Some(fn_data.span), item.span) {
+                        self.dumper.function(fn_data.clone().lower(self.tcx));
+                    }
+
+                    self.nest_tables(item.id, |v| v.process_formals(&decl.inputs,
+                                                                    &fn_data.qualname));
+                    self.process_generic_params(generics, item.span, &fn_data.qualname, item.id);
+                }
+
+                for arg in &decl.inputs {
+                    self.visit_ty(&arg.ty);
+                }
+
+                if let ast::FunctionRetTy::Ty(ref ret_ty) = decl.output {
+                    self.visit_ty(&ret_ty);
+                }
+            }
+            ast::ForeignItemKind::Static(ref ty, _) => {
+                if let Some(var_data) = self.save_ctxt.get_extern_item_data(item) {
+                    down_cast_data!(var_data, VariableData, item.span);
+                    if !self.span.filter_generated(Some(var_data.span), item.span) {
+                        self.dumper.variable(var_data.lower(self.tcx));
+                    }
+                }
+
+                self.visit_ty(ty);
+            }
+        }
+    }
 }

src/librustc_save_analysis/lib.rs

@@ -116,6 +116,46 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
         result
     }
 
+    pub fn get_extern_item_data(&self, item: &ast::ForeignItem) -> Option<Data> {
+        let qualname = format!("::{}", self.tcx.node_path_str(item.id));
+        match item.node {
+            ast::ForeignItemKind::Fn(ref decl, ref generics) => {
+                let sub_span = self.span_utils.sub_span_after_keyword(item.span, keywords::Fn);
+                Some(Data::FunctionData(FunctionData {
+                    id: item.id,
+                    name: item.ident.to_string(),
+                    qualname: qualname,
+                    declaration: None,
+                    span: sub_span.unwrap(),
+                    scope: self.enclosing_scope(item.id),
+                    value: make_signature(decl, generics),
+                    visibility: From::from(&item.vis),
+                    parent: None,
+                    docs: docs_for_attrs(&item.attrs),
+                    sig: self.sig_base_extern(item),
+                }))
+            }
+            ast::ForeignItemKind::Static(ref ty, m) => {
+                let keyword = if m { keywords::Mut } else { keywords::Static };
+                let sub_span = self.span_utils.sub_span_after_keyword(item.span, keyword);
+                Some(Data::VariableData(VariableData {
+                    id: item.id,
+                    kind: VariableKind::Static,
+                    name: item.ident.to_string(),
+                    qualname: qualname,
+                    span: sub_span.unwrap(),
+                    scope: self.enclosing_scope(item.id),
+                    parent: None,
+                    value: String::new(),
+                    type_value: ty_to_string(ty),
+                    visibility: From::from(&item.vis),
+                    docs: docs_for_attrs(&item.attrs),
+                    sig: Some(self.sig_base_extern(item)),
+                }))
+            }
+        }
+    }
+
     pub fn get_item_data(&self, item: &ast::Item) -> Option<Data> {
         match item.node {
             ast::ItemKind::Fn(ref decl, .., ref generics, _) => {
@@ -736,6 +776,21 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
         }
     }
 
+    fn sig_base_extern(&self, item: &ast::ForeignItem) -> Signature {
+        let text = self.span_utils.signature_string_for_span(item.span);
+        let name = item.ident.to_string();
+        let ident_start = text.find(&name).expect("Name not in signature?");
+        let ident_end = ident_start + name.len();
+        Signature {
+            span: mk_sp(item.span.lo, item.span.lo + BytePos(text.len() as u32)),
+            text: text,
+            ident_start: ident_start,
+            ident_end: ident_end,
+            defs: vec![],
+            refs: vec![],
+        }
+    }
+
     #[inline]
     pub fn enclosing_scope(&self, id: NodeId) -> NodeId {
         self.tcx.hir.get_enclosing_scope(id).unwrap_or(CRATE_NODE_ID)

src/test/run-make/save-analysis-fail/foo.rs

@@ -448,3 +448,8 @@ fn test_format_args() {
     print!("{0} + {} = {}", x, y);
     print!("x is {}, y is {1}, name is {n}", x, y, n = name);
 }
+
+extern {
+    static EXTERN_FOO: u8;
+    fn extern_foo(a: u8, b: i32) -> String;
+}