Move resolve_path to rustc_builtin_macros and make it private

1 files changed, 43 insertions, 4 deletions

diff --git a/compiler/rustc_builtin_macros/src/source_util.rs b/compiler/rustc_builtin_macros/src/source_util.rs
index bbc8e62d68f..be628c9202c 100644
--- a/compiler/rustc_builtin_macros/src/source_util.rs
+++ b/compiler/rustc_builtin_macros/src/source_util.rs
@@ -3,15 +3,17 @@ use rustc_ast::ptr::P;
 use rustc_ast::token;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast_pretty::pprust;
+use rustc_errors::PResult;
 use rustc_expand::base::{self, *};
 use rustc_expand::module::DirOwnership;
 use rustc_parse::parser::{ForceCollect, Parser};
 use rustc_parse::{self, new_parser_from_file};
 use rustc_session::lint::builtin::INCOMPLETE_INCLUDE;
 use rustc_span::symbol::Symbol;
-use rustc_span::{self, Pos, Span};
+use rustc_span::{self, FileName, Pos, Span};
 
 use smallvec::SmallVec;
+use std::path::PathBuf;
 use std::rc::Rc;
 
 // These macros all relate to the file system; they either return
@@ -102,7 +104,7 @@ pub fn expand_include<'cx>(
         return DummyResult::any(sp);
     };
     // The file will be added to the code map by the parser
-    let file = match cx.resolve_path(file, sp) {
+    let file = match resolve_path(cx, file, sp) {
         Ok(f) => f,
         Err(mut err) => {
             err.emit();
@@ -171,7 +173,7 @@ pub fn expand_include_str(
     let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_str!") else {
         return DummyResult::any(sp);
     };
-    let file = match cx.resolve_path(file, sp) {
+    let file = match resolve_path(cx, file, sp) {
         Ok(f) => f,
         Err(mut err) => {
             err.emit();
@@ -205,7 +207,7 @@ pub fn expand_include_bytes(
     let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_bytes!") else {
         return DummyResult::any(sp);
     };
-    let file = match cx.resolve_path(file, sp) {
+    let file = match resolve_path(cx, file, sp) {
         Ok(f) => f,
         Err(mut err) => {
             err.emit();
@@ -220,3 +222,40 @@ pub fn expand_include_bytes(
         }
     }
 }
+
+/// Resolves a `path` mentioned inside Rust code, returning an absolute path.
+///
+/// This unifies the logic used for resolving `include_X!`.
+fn resolve_path<'a>(
+    cx: &mut ExtCtxt<'a>,
+    path: impl Into<PathBuf>,
+    span: Span,
+) -> PResult<'a, PathBuf> {
+    let path = path.into();
+
+    // Relative paths are resolved relative to the file in which they are found
+    // after macro expansion (that is, they are unhygienic).
+    if !path.is_absolute() {
+        let callsite = span.source_callsite();
+        let mut result = match cx.source_map().span_to_filename(callsite) {
+            FileName::Real(name) => name
+                .into_local_path()
+                .expect("attempting to resolve a file path in an external file"),
+            FileName::DocTest(path, _) => path,
+            other => {
+                return Err(cx.struct_span_err(
+                    span,
+                    &format!(
+                        "cannot resolve relative path in non-file source `{}`",
+                        cx.source_map().filename_for_diagnostics(&other)
+                    ),
+                ));
+            }
+        };
+        result.pop();
+        result.push(path);
+        Ok(result)
+    } else {
+        Ok(path)
+    }
+}