3 files changed, 45 insertions, 3 deletions
diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index 839609339f..d72846a691 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -1890,6 +1890,8 @@ func dwarfGenerateDebugInfo(ctxt *Link) {
 	// global variables. For each global of this sort, locate
 	// the corresponding compiler-generated DIE symbol and tack
 	// it onto the list associated with the unit.
+	// Also looks for dictionary symbols and generates DIE symbols for each
+	// type they reference.
 	for idx := loader.Sym(1); idx < loader.Sym(d.ldr.NDef()); idx++ {
 		if !d.ldr.AttrReachable(idx) ||
 			d.ldr.AttrNotInSymbolTable(idx) ||
@@ -1903,9 +1905,21 @@ func dwarfGenerateDebugInfo(ctxt *Link) {
 		default:
 			continue
 		}
-		// Skip things with no type
+		// Skip things with no type, unless it's a dictionary
 		gt := d.ldr.SymGoType(idx)
 		if gt == 0 {
+			if t == sym.SRODATA {
+				if d.ldr.IsDict(idx) {
+					// This is a dictionary, make sure that all types referenced by this dictionary are reachable
+					relocs := d.ldr.Relocs(idx)
+					for i := 0; i < relocs.Count(); i++ {
+						reloc := relocs.At(i)
+						if reloc.Type() == objabi.R_USEIFACE {
+							d.defgotype(reloc.Sym())
+						}
+					}
+				}
+			}
 			continue
 		}
 		// Skip file local symbols (this includes static tmps, stack
diff --git a/src/cmd/link/internal/ld/dwarf_test.go b/src/cmd/link/internal/ld/dwarf_test.go
index 3d112d97a4..db9002491e 100644
--- a/src/cmd/link/internal/ld/dwarf_test.go
+++ b/src/cmd/link/internal/ld/dwarf_test.go
@@ -1749,7 +1749,9 @@ func main() {
 }
 
 func TestDictIndex(t *testing.T) {
-	// Check that variables with a parametric type have a dictionary index attribute
+	// Check that variables with a parametric type have a dictionary index
+	// attribute and that types that are only referenced through dictionaries
+	// have DIEs.
 	testenv.MustHaveGoBuild(t)
 
 	if runtime.GOOS == "plan9" {
@@ -1765,6 +1767,8 @@ package main
 
 import "fmt"
 
+type CustomInt int
+
 func testfn[T any](arg T) {
 	var mapvar = make(map[int]T)
 	mapvar[0] = arg
@@ -1772,7 +1776,7 @@ func testfn[T any](arg T) {
 }
 
 func main() {
-	testfn("test")
+	testfn(CustomInt(3))
 }
 `
 
@@ -1829,4 +1833,19 @@ func main() {
 			t.Errorf("could not find DW_AT_go_dict_index attribute offset %#x (%T)", off, entry.Val(intdwarf.DW_AT_go_dict_index))
 		}
 	}
+
+	rdr.Seek(0)
+	ex := examiner{}
+	if err := ex.populate(rdr); err != nil {
+		t.Fatalf("error reading DWARF: %v", err)
+	}
+	for _, typeName := range []string{"main.CustomInt", "map[int]main.CustomInt"} {
+		dies := ex.Named(typeName)
+		if len(dies) != 1 {
+			t.Errorf("wanted 1 DIE named %s, found %v", typeName, len(dies))
+		}
+		if dies[0].Val(intdwarf.DW_AT_go_runtime_type).(uint64) == 0 {
+			t.Errorf("type %s does not have DW_AT_go_runtime_type", typeName)
+		}
+	}
 }
diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go
index f144e00f37..b9a1da6f45 100644
--- a/src/cmd/link/internal/loader/loader.go
+++ b/src/cmd/link/internal/loader/loader.go
@@ -1209,6 +1209,15 @@ func (l *Loader) IsItab(i Sym) bool {
 	return r.Sym(li).IsItab()
 }
 
+// Returns whether this symbol is a dictionary symbol.
+func (l *Loader) IsDict(i Sym) bool {
+	if l.IsExternal(i) {
+		return false
+	}
+	r, li := l.toLocal(i)
+	return r.Sym(li).IsDict()
+}
+
 // Return whether this is a trampoline of a deferreturn call.
 func (l *Loader) IsDeferReturnTramp(i Sym) bool {
 	return l.deferReturnTramp[i]