Add run-make test for -Zembed-source=yes

tests/run-make/embed-source-dwarf/main.rs

@@ -0,0 +1,2 @@
+// hello
+fn main() {}

tests/run-make/embed-source-dwarf/rmake.rs

@@ -0,0 +1,70 @@
+//@ ignore-windows
+//@ ignore-apple
+
+// LLVM 17's embed-source implementation requires that source code is attached
+// for all files in the output DWARF debug info. This restriction was lifted in
+// LLVM 18 (87e22bdd2bd6d77d782f9d64b3e3ae5bdcd5080d).
+//@ min-llvm-version: 18
+
+// This test should be replaced with one in tests/debuginfo once we can easily
+// tell via GDB or LLDB if debuginfo contains source code. Cheap tricks in LLDB
+// like setting an invalid source map path don't appear to work, maybe this'll
+// become easier once GDB supports DWARFv6?
+
+use std::collections::HashMap;
+use std::path::PathBuf;
+use std::rc::Rc;
+
+use gimli::{AttributeValue, EndianRcSlice, Reader, RunTimeEndian};
+use object::{Object, ObjectSection};
+use run_make_support::{gimli, object, rfs, rustc};
+
+fn main() {
+    let output = PathBuf::from("embed-source-main");
+    rustc()
+        .input("main.rs")
+        .output(&output)
+        .arg("-g")
+        .arg("-Zembed-source=yes")
+        .arg("-Zdwarf-version=5")
+        .run();
+    let output = rfs::read(output);
+    let obj = object::File::parse(output.as_slice()).unwrap();
+    let endian = if obj.is_little_endian() { RunTimeEndian::Little } else { RunTimeEndian::Big };
+    let dwarf = gimli::Dwarf::load(|section| -> Result<_, ()> {
+        let data = obj.section_by_name(section.name()).map(|s| s.uncompressed_data().unwrap());
+        Ok(EndianRcSlice::new(Rc::from(data.unwrap_or_default().as_ref()), endian))
+    })
+    .unwrap();
+
+    let mut sources = HashMap::new();
+
+    let mut iter = dwarf.units();
+    while let Some(header) = iter.next().unwrap() {
+        let unit = dwarf.unit(header).unwrap();
+        let unit = unit.unit_ref(&dwarf);
+
+        if let Some(program) = &unit.line_program {
+            let header = program.header();
+            for file in header.file_names() {
+                if let Some(source) = file.source() {
+                    let path = unit
+                        .attr_string(file.path_name())
+                        .unwrap()
+                        .to_string_lossy()
+                        .unwrap()
+                        .to_string();
+                    let source =
+                        unit.attr_string(source).unwrap().to_string_lossy().unwrap().to_string();
+                    if !source.is_empty() {
+                        sources.insert(path, source);
+                    }
+                }
+            }
+        }
+    }
+
+    dbg!(&sources);
+    assert_eq!(sources.len(), 1);
+    assert_eq!(sources.get("main.rs").unwrap(), "// hello\nfn main() {}\n");
+}