cmd/compile/internal/gc: use slice instead of linked list for nodes to export

Change-Id: Ib79ab787fdc90a5a29b25474d91afa9bfaf51276
Reviewed-on: https://go-review.googlesource.com/13589Reviewed-by: Minux Ma <minux@golang.org>

src/cmd/compile/internal/gc/export.go

@@ -31,7 +31,7 @@ func exportsym(n *Node) {
 	if Debug['E'] != 0 {
 		fmt.Printf("export symbol %v\n", n.Sym)
 	}
-	exportlist = list(exportlist, n)
+	exportlist = append(exportlist, n)
 }
 
 func exportname(s string) bool {
@@ -124,7 +124,7 @@ func reexportdep(n *Node) {
 				if Debug['E'] != 0 {
 					fmt.Printf("reexport name %v\n", n.Sym)
 				}
-				exportlist = list(exportlist, n)
+				exportlist = append(exportlist, n)
 			}
 		}
 
@@ -140,7 +140,7 @@ func reexportdep(n *Node) {
 				if Debug['E'] != 0 {
 					fmt.Printf("reexport type %v from declaration\n", t.Sym)
 				}
-				exportlist = list(exportlist, t.Sym.Def)
+				exportlist = append(exportlist, t.Sym.Def)
 			}
 		}
 
@@ -154,7 +154,7 @@ func reexportdep(n *Node) {
 				if Debug['E'] != 0 {
 					fmt.Printf("reexport literal type %v\n", t.Sym)
 				}
-				exportlist = list(exportlist, t.Sym.Def)
+				exportlist = append(exportlist, t.Sym.Def)
 			}
 		}
 		fallthrough
@@ -164,7 +164,7 @@ func reexportdep(n *Node) {
 			if Debug['E'] != 0 {
 				fmt.Printf("reexport literal/type %v\n", n.Sym)
 			}
-			exportlist = list(exportlist, n)
+			exportlist = append(exportlist, n)
 		}
 
 		// for operations that need a type when rendered, put the type on the export list.
@@ -193,7 +193,7 @@ func reexportdep(n *Node) {
 			if Debug['E'] != 0 {
 				fmt.Printf("reexport type for expression %v\n", t.Sym)
 			}
-			exportlist = list(exportlist, t.Sym.Def)
+			exportlist = append(exportlist, t.Sym.Def)
 		}
 	}
 
@@ -376,9 +376,12 @@ func dumpexport() {
 		}
 	}
 
-	for l := exportlist; l != nil; l = l.Next {
-		lineno = l.N.Lineno
-		dumpsym(l.N.Sym)
+	// exportlist grows during iteration - cannot use range
+	for len(exportlist) > 0 {
+		n := exportlist[0]
+		exportlist = exportlist[1:]
+		lineno = n.Lineno
+		dumpsym(n.Sym)
 	}
 
 	fmt.Fprintf(bout, "\n$$\n")

src/cmd/compile/internal/gc/go.go

@@ -586,7 +586,7 @@ var xtop *NodeList
 
 var externdcl *NodeList
 
-var exportlist *NodeList
+var exportlist []*Node
 
 var importlist *NodeList // imported functions and methods with inlinable bodies