For untyped objects, still recognize ptr/nonptr distinction.

Author: randall77

gocore/object.go

@@ -149,6 +149,29 @@ func (p *Program) isPtr(a core.Address) bool {
 	return p.proc.ReadUint8(p.bitmapEnd.Add(-(off>>2)-1))>>uint(off&3)&1 != 0
 }
 
+// IsPtr reports whether the inferior at address a contains a pointer.
+func (p *Program) IsPtr(a core.Address) bool {
+	if a >= p.arenaStart && a < p.arenaUsed {
+		return p.isPtr(a)
+	}
+	for _, m := range p.modules {
+		for _, s := range [2]string{"data", "bss"} {
+			min := core.Address(m.r.Field(s).Uintptr())
+			max := core.Address(m.r.Field("e" + s).Uintptr())
+			if a < min || a >= max {
+				continue
+			}
+			gc := m.r.Field("gc" + s + "mask").Field("bytedata").Address()
+			i := a.Sub(min)
+			return p.proc.ReadUint8(gc.Add(i/8))>>uint(i%8) != 0
+		}
+	}
+	// Everywhere is isn't a pointer. At least, not a pointer into the Go heap.
+	// TODO: stacks?
+	// TODO: finalizers?
+	return false
+}
+
 // FindObject finds the object containing a.  Returns that object and the offset within
 // that object to which a points.
 // Returns 0,0 if a doesn't point to a live heap object.

html.go

@@ -66,20 +66,25 @@ func serveHtml(c *gocore.Program) {
 			end = n * typ.Size
 		}
 		for i := end; i < size; i += c.Process().PtrSize() {
-			fmt.Fprintf(w, "<tr><td>f%d</td><td colspan=\"2\">?</td><td><pre>", i)
-			for j := int64(0); j < c.Process().PtrSize(); j++ {
-				fmt.Fprintf(w, "%02x ", c.Process().ReadUint8(addr.Add(i+j)))
-			}
-			fmt.Fprintf(w, "</pre></td><td><pre>")
-			for j := int64(0); j < c.Process().PtrSize(); j++ {
-				r := c.Process().ReadUint8(addr.Add(i + j))
-				if r >= 32 && r <= 126 {
-					fmt.Fprintf(w, "%s", html.EscapeString(string(rune(r))))
-				} else {
-					fmt.Fprintf(w, ".")
+			fmt.Fprintf(w, "<tr><td>f%d</td><td colspan=\"2\">?</td>", i)
+			if c.IsPtr(addr.Add(i)) {
+				fmt.Fprintf(w, "<td>%s</td>", htmlPointer(c, c.Process().ReadPtr(addr.Add(i))))
+			} else {
+				fmt.Fprintf(w, "<td><pre>")
+				for j := int64(0); j < c.Process().PtrSize(); j++ {
+					fmt.Fprintf(w, "%02x ", c.Process().ReadUint8(addr.Add(i+j)))
+				}
+				fmt.Fprintf(w, "</pre></td><td><pre>")
+				for j := int64(0); j < c.Process().PtrSize(); j++ {
+					r := c.Process().ReadUint8(addr.Add(i + j))
+					if r >= 32 && r <= 126 {
+						fmt.Fprintf(w, "%s", html.EscapeString(string(rune(r))))
+					} else {
+						fmt.Fprintf(w, ".")
+					}
 				}
+				fmt.Fprintf(w, "</pre></td>")
 			}
-			fmt.Fprintf(w, "</pre></td>")
 			fmt.Fprintf(w, "</tr>\n")
 		}
 		fmt.Fprintf(w, "</table>\n")