Support reference types in the DWARF transform (#1986)

tests/all/debug/lldb.rs

@@ -166,3 +166,37 @@ check: resuming
     )?;
     Ok(())
 }
+
+#[test]
+#[ignore]
+#[cfg(all(
+    any(target_os = "linux", target_os = "macos"),
+    target_pointer_width = "64"
+))]
+pub fn test_debug_dwarf_ref() -> Result<()> {
+    let output = lldb_with_script(
+        &[
+            "-g",
+            "--opt-level",
+            "0",
+            "tests/all/debug/testsuite/fraction-norm.wasm",
+        ],
+        r#"b fraction-norm.cc:26
+r
+p __vmctx->set(),n->denominator
+c"#,
+    )?;
+
+    check_lldb_output(
+        &output,
+        r#"
+check: Breakpoint 1: no locations (pending)
+check: stop reason = breakpoint 1.1
+check: frame #0
+sameln: norm(n=(__ptr =
+check: = 27
+check: resuming
+"#,
+    )?;
+    Ok(())
+}

tests/all/debug/testsuite/fraction-norm.cc

@@ -0,0 +1,40 @@
+// Compile with:
+//   clang++ --target=wasm32 fraction-norm.cc -o fraction-norm.wasm -g \
+//     -O0 -nostdlib -fdebug-prefix-map=$PWD=.
+
+struct Fraction {
+  long numerator;
+  long denominator;
+};
+
+inline long abs(long x)
+{
+  return x >= 0 ? x : -x;  
+}
+
+extern "C"
+void norm(Fraction &n)
+{
+  long a = abs(n.numerator), b = abs(n.denominator);
+  if (a == 0 || b == 0) return;
+  do {
+   a %= b;
+   if (a == 0) break;
+   b %= a;
+  } while (b > 0);
+  long gcd = a + b;
+  if (n.denominator > 0) {
+    n.numerator /= gcd;
+    n.denominator /= gcd;
+  } else {
+    n.numerator /= -gcd;
+    n.denominator /= -gcd;
+  }
+}
+
+extern "C"
+void _start()
+{
+  Fraction c = {6, 27};
+  norm(c);
+}