[dev.link] cmd/link: add storage and methods for read/write of Sym value

Add loader methods SymValue() and SetSymValue() to get/set the
value of a symbol by global index.

Change-Id: Ifc71480fc34c719ad00506d0828edf36c1a57119
Reviewed-on: https://go-review.googlesource.com/c/go/+/211302
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

1 files changed, 14 insertions, 1 deletions

diff --git a/src/cmd/link/internal/loader/loader_test.go b/src/cmd/link/internal/loader/loader_test.go
index 4dde9e04e8..ec3090bd5a 100644
--- a/src/cmd/link/internal/loader/loader_test.go
+++ b/src/cmd/link/internal/loader/loader_test.go
@@ -32,7 +32,7 @@ func TestAddMaterializedSymbol(t *testing.T) {
 
 	// Create some syms from a dummy object file symbol to get things going.
 	addDummyObjSym(t, ldr, or, "type.uint8")
-	addDummyObjSym(t, ldr, or, "mumble")
+	ts2 := addDummyObjSym(t, ldr, or, "mumble")
 	addDummyObjSym(t, ldr, or, "type.string")
 
 	// Create some external symbols.
@@ -96,4 +96,17 @@ func TestAddMaterializedSymbol(t *testing.T) {
 	if !ldr.AttrVisibilityHidden(es3) {
 		t.Errorf("expected hidden after update")
 	}
+
+	// Test get/set symbol value.
+	toTest := []Sym{ts2, es3}
+	for i, s := range toTest {
+		if v := ldr.SymValue(s); v != 0 {
+			t.Errorf("ldr.Value(%d): expected 0 got %d\n", s, v)
+		}
+		nv := int64(i + 101)
+		ldr.SetSymValue(s, nv)
+		if v := ldr.SymValue(s); v != nv {
+			t.Errorf("ldr.SetValue(%d,%d): expected %d got %d\n", s, nv, nv, v)
+		}
+	}
 }