gc: fix order of evaluation

Pulling function calls out to happen before the
expression being evaluated was causing illegal
reorderings even without inlining; with inlining
it got worse.  This CL adds a separate ordering pass
to move things with a fixed order out of expressions
and into the statement sequence, where they will
not be reordered by walk.

Replaces lvd's CL 5534079.

Fixes issue 2740.

R=lvd
CC=golang-dev
http://codereview.appspot.com/5569062

3 files changed, 250 insertions, 12 deletions

diff --git a/test/fixedbugs/bug401.go b/test/fixedbugs/bug401.go
index baad1bc7d..553e217b7 100644
--- a/test/fixedbugs/bug401.go
+++ b/test/fixedbugs/bug401.go
@@ -1,29 +1,46 @@
-// $G $D/$F.go || echo "Bug398"
+// $G $D/$F.go && $L $F.$A && ./$A.out || echo "Bug401"
 
 // Copyright 2011 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.
 
 // Issue 2582
-package foo
-    
-type T struct {}
+package main
+
+type T struct{}
+
 func (T) cplx() complex128 {
-	for false {}  // avoid inlining
-	return complex(1,0)
+	for false {
+	} // avoid inlining
+	return complex(1, 0)
+}
+
+func (T) cplx2() complex128 {
+	return complex(0, 1)
 }
 
 type I interface {
 	cplx() complex128
 }
 
-func f(e float32, t T) {
+func main() {
 
-    	_ = real(t.cplx())
-    	_ = imag(t.cplx())
+	var t T
+
+	if v := real(t.cplx()); v != 1 {
+		panic("not-inlined complex call failed")
+	}
+	_ = imag(t.cplx())
+
+	_ = real(t.cplx2())
+	if v := imag(t.cplx2()); v != 1 {
+		panic("potentially inlined complex call failed")
+	}
 
 	var i I
 	i = t
-    	_ = real(i.cplx())
-    	_ = imag(i.cplx())
-}
\ No newline at end of file
+	if v := real(i.cplx()); v != 1 {
+		panic("potentially inlined complex call failed")
+	}
+	_ = imag(i.cplx())
+}
diff --git a/test/func8.go b/test/func8.go
new file mode 100644
index 000000000..bb6106453
--- /dev/null
+++ b/test/func8.go
@@ -0,0 +1,47 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2011 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 main
+
+var calledf int
+
+func f() int {
+	calledf++
+	return 0
+}
+
+func g() int {
+	return calledf
+}
+
+var xy string
+
+func x() bool {
+	for false {
+	} // no inlining
+	xy += "x"
+	return false
+}
+
+func y() string {
+	for false {
+	} // no inlining
+	xy += "y"
+	return "abc"
+}
+
+func main() {
+	if f() == g() {
+		println("wrong f,g order")
+	}
+
+	if x() == (y() == "abc") {
+		panic("wrong compare")
+	}
+	if xy != "xy" {
+		println("wrong x,y order")
+	}
+}
diff --git a/test/reorder2.go b/test/reorder2.go
new file mode 100644
index 000000000..3e149853a
--- /dev/null
+++ b/test/reorder2.go
@@ -0,0 +1,174 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2010 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.
+
+// derived from fixedbugs/bug294.go
+
+package main
+
+var log string
+
+type TT int
+
+func (t TT) a(s string) TT {
+	log += "a(" + s + ")"
+	return t
+}
+
+func (TT) b(s string) string {
+	log += "b(" + s + ")"
+	return s
+}
+
+type F func(s string) F
+
+func a(s string) F {
+	log += "a(" + s + ")"
+	return F(a)
+}
+
+func b(s string) string {
+	log += "b(" + s + ")"
+	return s
+}
+
+type I interface {
+	a(s string) I
+	b(s string) string
+}
+
+type T1 int
+
+func (t T1) a(s string) I {
+	log += "a(" + s + ")"
+	return t
+}
+
+func (T1) b(s string) string {
+	log += "b(" + s + ")"
+	return s
+}
+
+// f(g(), h()) where g is not inlinable but h is will have the same problem.
+// As will x := g() + h() (same conditions).
+// And g() <- h().
+func f(x, y string) {
+	log += "f(" + x + ", " + y + ")"
+}
+
+func ff(x, y string) {
+	for false {
+	} // prevent inl
+	log += "ff(" + x + ", " + y + ")"
+}
+
+func h(x string) string {
+	log += "h(" + x + ")"
+	return x
+}
+
+func g(x string) string {
+	for false {
+	} // prevent inl
+	log += "g(" + x + ")"
+	return x
+}
+
+func main() {
+	err := 0
+	var t TT
+	if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
+		println("expecting a(1)a(2)a(3) , got ", log)
+		err++
+	}
+	log = ""
+
+	if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
+		println("expecting a(1)b(2)a(2), got ", log)
+		err++
+	}
+	log = ""
+	if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
+		println("expecting a(3)b(4)a(4)b(5)a(5), got ", log)
+		err++
+	}
+	log = ""
+	var i I = T1(0)
+	if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
+		println("expecting a(6)ba(7)ba(8)ba(9), got", log)
+		err++
+	}
+	log = ""
+
+	if s := t.a("1").b("3"); log != "a(1)b(3)" || s != "3" {
+		println("expecting a(1)b(3) and 3, got ", log, " and ", s)
+		err++
+	}
+	log = ""
+
+	if s := t.a("1").a(t.b("2")).b("3") + t.a("4").b("5"); log != "a(1)b(2)a(2)b(3)a(4)b(5)" || s != "35" {
+		println("expecting a(1)b(2)a(2)b(3)a(4)b(5) and 35, got ", log, " and ", s)
+		err++
+	}
+	log = ""
+
+	if s := t.a("4").b("5") + t.a("1").a(t.b("2")).b("3"); log != "a(4)b(5)a(1)b(2)a(2)b(3)" || s != "53" {
+		println("expecting a(4)b(5)a(1)b(2)a(2)b(3) and 35, got ", log, " and ", s)
+		err++
+	}
+	log = ""
+
+	if ff(g("1"), g("2")); log != "g(1)g(2)ff(1, 2)" {
+		println("expecting g(1)g(2)ff..., got ", log)
+		err++
+	}
+	log = ""
+
+	if ff(g("1"), h("2")); log != "g(1)h(2)ff(1, 2)" {
+		println("expecting g(1)h(2)ff..., got ", log)
+		err++
+	}
+	log = ""
+
+	if ff(h("1"), g("2")); log != "h(1)g(2)ff(1, 2)" {
+		println("expecting h(1)g(2)ff..., got ", log)
+		err++
+	}
+	log = ""
+
+	if ff(h("1"), h("2")); log != "h(1)h(2)ff(1, 2)" {
+		println("expecting h(1)h(2)ff..., got ", log)
+		err++
+	}
+	log = ""
+
+	if s := g("1") + g("2"); log != "g(1)g(2)" || s != "12" {
+		println("expecting g1g2 and 12, got ", log, " and ", s)
+		err++
+	}
+	log = ""
+
+	if s := g("1") + h("2"); log != "g(1)h(2)" || s != "12" {
+		println("expecting g1h2 and 12, got ", log, " and ", s)
+		err++
+	}
+	log = ""
+
+	if s := h("1") + g("2"); log != "h(1)g(2)" || s != "12" {
+		println("expecting h1g2 and 12, got ", log, " and ", s)
+		err++
+	}
+	log = ""
+
+	if s := h("1") + h("2"); log != "h(1)h(2)" || s != "12" {
+		println("expecting h1h2 and 12, got ", log, " and ", s)
+		err++
+	}
+	log = ""
+
+	if err > 0 {
+		panic("fail")
+	}
+}