commit a21cf5b6a281df2c3506105cecfbeeda70afca1c
author David Chase <drchase@google.com> Fri May 15 12:19:07 2015 -0400
committer David Chase <drchase@google.com> Mon May 18 15:34:39 2015 +0000
tree 0f47567dddaaca8cbbf060a99eaa24c519fd5117
parent f0dd002895b48595f6c14f2bf606775289f59d5f

cmd/internal/gc: extend escape analysis to pointers in slices

Modified esc.go to allow slice literals (before append)
to be non-escaping.  Modified tests to account for changes
in escape behavior and to also test the two cases that
were previously not tested.

Also minor cleanups to debug-printing within esc.go

Allocation stats for running compiler
( cd src/html/template;
  for i in {1..5} ; do
     go tool 6g -memprofile=testzz.${i}.prof  -memprofilerate=1 *.go ;
     go tool pprof -alloc_objects -text  testzz.${i}.prof ;
     done ; )
before about 86k allocations
after  about 83k allocations

Fixes #8972

Change-Id: Ib61dd70dc74adb40d6f6fdda6eaa4bf7d83481de
Reviewed-on: https://go-review.googlesource.com/10118
Reviewed-by: Russ Cox <rsc@golang.org>

test/escape2n.go

diff --git a/test/escape2n.go b/test/escape2n.go
index bf8c534..56f05eb 100644
--- a/test/escape2n.go
+++ b/test/escape2n.go
@@ -787,7 +787,7 @@
 }
 
 // does not leak m
-func foo94(m map[*int]*int, b bool) *int { // ERROR "foo94 m does not escape$"
+func foo94(m map[*int]*int, b bool) *int { // ERROR "leaking param: m to result ~r2 level=1"
 	for k, v := range m {
 		if b {
 			return k
@@ -802,8 +802,8 @@
 	m[x] = x
 }
 
-// does not leak m
-func foo96(m []*int) *int { // ERROR "foo96 m does not escape$"
+// does not leak m but does leak content
+func foo96(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
 	return m[0]
 }
 
@@ -823,7 +823,7 @@
 }
 
 // does not leak m
-func foo100(m []*int) *int { // ERROR "foo100 m does not escape$"
+func foo100(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
 	for _, v := range m {
 		return v
 	}
@@ -863,8 +863,8 @@
 	copy(y, x)
 }
 
-// does not leak x
-func foo105(x []*int) { // ERROR "foo105 x does not escape$"
+// does not leak x but does leak content
+func foo105(x []*int) { // ERROR "leaking param content: x"
 	_ = append(y, x...)
 }
 
@@ -894,7 +894,7 @@
 	return m[nil]
 }
 
-func foo111(x *int) *int { // ERROR "leaking param: x$"
+func foo111(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0"
 	m := []*int{x} // ERROR "foo111 \[\]\*int literal does not escape$"
 	return m[0]
 }