cmd/compile/internal/gc: add unit test for cmpstackvar
A followup CL will rewrite listsort to use the new cmpstackvarlt and
change cmpstackvar to avoid stringsCompare.
Change-Id: Idf0857a3bd67f9e2243ba82aa0bff510612927c3
Reviewed-on: https://go-review.googlesource.com/14611
Reviewed-by: Dave Cheney <dave@cheney.net>
diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go
index 9b3ef68..7c918c5 100644
--- a/src/cmd/compile/internal/gc/pgen.go
+++ b/src/cmd/compile/internal/gc/pgen.go
@@ -164,6 +164,11 @@
ggloblsym(sym, int32(off), obj.RODATA|obj.LOCAL)
}
+// cmpstackvarlt reports whether the stack variable a sorts before b.
+func cmpstackvarlt(a, b *Node) bool {
+ return cmpstackvar(a, b) < 0
+}
+
// Sort the list of stack variables. Autos after anything else,
// within autos, unused after used, within used, things with
// pointers first, zeroed things first, and then decreasing size.
diff --git a/src/cmd/compile/internal/gc/pgen_test.go b/src/cmd/compile/internal/gc/pgen_test.go
new file mode 100644
index 0000000..ce8b2b3
--- /dev/null
+++ b/src/cmd/compile/internal/gc/pgen_test.go
@@ -0,0 +1,102 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gc
+
+import "testing"
+
+// Test all code paths for cmpstackvarlt.
+func TestCmpstackvar(t *testing.T) {
+ testdata := []struct {
+ a, b Node
+ lt bool
+ }{
+ {
+ Node{Class: PAUTO},
+ Node{Class: PFUNC},
+ false,
+ },
+ {
+ Node{Class: PFUNC},
+ Node{Class: PAUTO},
+ true,
+ },
+ {
+ Node{Class: PFUNC, Xoffset: 0},
+ Node{Class: PFUNC, Xoffset: 10},
+ true,
+ },
+ {
+ Node{Class: PFUNC, Xoffset: 20},
+ Node{Class: PFUNC, Xoffset: 10},
+ false,
+ },
+ {
+ Node{Class: PFUNC, Xoffset: 10},
+ Node{Class: PFUNC, Xoffset: 10},
+ false,
+ },
+ {
+ Node{Class: PAUTO, Used: true},
+ Node{Class: PAUTO, Used: false},
+ true,
+ },
+ {
+ Node{Class: PAUTO, Used: false},
+ Node{Class: PAUTO, Used: true},
+ false,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{Haspointers: 1}}, // haspointers -> false
+ Node{Class: PAUTO, Type: &Type{Haspointers: 2}}, // haspointers -> true
+ false,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{Haspointers: 2}}, // haspointers -> true
+ Node{Class: PAUTO, Type: &Type{Haspointers: 1}}, // haspointers -> false
+ true,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{Needzero: true}},
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{Needzero: false}},
+ true,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{Needzero: false}},
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{Needzero: true}},
+ false,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{Width: 1}, Name: &Name{}},
+ Node{Class: PAUTO, Type: &Type{Width: 2}, Name: &Name{}},
+ false,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{Width: 2}, Name: &Name{}},
+ Node{Class: PAUTO, Type: &Type{Width: 1}, Name: &Name{}},
+ true,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{}, Sym: &Sym{Name: "abc"}},
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{}, Sym: &Sym{Name: "xyz"}},
+ true,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{}, Sym: &Sym{Name: "abc"}},
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{}, Sym: &Sym{Name: "abc"}},
+ false,
+ },
+ {
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{}, Sym: &Sym{Name: "xyz"}},
+ Node{Class: PAUTO, Type: &Type{}, Name: &Name{}, Sym: &Sym{Name: "abc"}},
+ false,
+ },
+ }
+ for _, d := range testdata {
+ got := cmpstackvarlt(&d.a, &d.b)
+ if got != d.lt {
+ t.Errorf("want %#v < %#v", d.a, d.b)
+ }
+ }
+}
