cmd/compile/internal/gc: unify self-assignment checks in esc.go

Move slice self-assign check into isSelfAssign function. Make debug output consistent for all self-assignment cases. Change-Id: I0e4cc7b3c1fcaeace7226dd80a0dc1ea97347a55 Reviewed-on: https://go-review.googlesource.com/136276 Run-TryBot: Iskander Sharipov <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Cherry Zhang <[email protected]>
cloudflare · Sep 20, 2018 · 499fbb1 · 499fbb1
1 parent 9a033bf
commit 499fbb1
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Showing 3 changed files with 24 additions and 27 deletions.
diff --git a/src/cmd/compile/internal/gc/esc.go b/src/cmd/compile/internal/gc/esc.go
@@ -705,6 +705,10 @@ func (e *EscState) isSliceSelfAssign(dst, src *Node) bool {
 // isSelfAssign reports whether assignment from src to dst can
 // be ignored by the escape analysis as it's effectively a self-assignment.
 func (e *EscState) isSelfAssign(dst, src *Node) bool {
+ if e.isSliceSelfAssign(dst, src) {
+ return true
+ }
+
  // Detect trivial assignments that assign back to the same object.
  //
  // It covers these cases:
@@ -890,13 +894,6 @@ opSwitch:
 
  case OAS, OASOP:
  // Filter out some no-op assignments for escape analysis.
- if e.isSliceSelfAssign(n.Left, n.Right) {
- if Debug['m'] != 0 {
- Warnl(n.Pos, "%v ignoring self-assignment to %S", e.curfnSym(n), n.Left)
- }
-
- break
- }
  if e.isSelfAssign(n.Left, n.Right) {
  if Debug['m'] != 0 {
  Warnl(n.Pos, "%v ignoring self-assignment in %S", e.curfnSym(n), n)

diff --git a/test/escape2.go b/test/escape2.go
@@ -1602,24 +1602,24 @@ type Buffer struct {
 }
 
 func (b *Buffer) foo() { // ERROR "\(\*Buffer\).foo b does not escape$"
- b.buf1 = b.buf1[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
- b.buf1 = b.buf1[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
- b.buf1 = b.buf2[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
- b.buf1 = b.buf2[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
+ b.buf1 = b.buf1[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf1\[1:2\]$"
+ b.buf1 = b.buf1[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf1\[1:2:3\]$"
+ b.buf1 = b.buf2[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf2\[1:2\]$"
+ b.buf1 = b.buf2[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf2\[1:2:3\]$"
 }
 
 func (b *Buffer) bar() { // ERROR "leaking param: b$"
  b.buf1 = b.arr[1:2] // ERROR "b.arr escapes to heap$"
 }
 
 func (b *Buffer) arrayPtr() { // ERROR "\(\*Buffer\).arrayPtr b does not escape"
- b.buf1 = b.arrPtr[1:2] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment to b.buf1"
- b.buf1 = b.arrPtr[1:2:3] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment to b.buf1"
+ b.buf1 = b.arrPtr[1:2] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment in b.buf1 = b.arrPtr\[1:2\]$"
+ b.buf1 = b.arrPtr[1:2:3] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment in b.buf1 = b.arrPtr\[1:2:3\]$"
 }
 
 func (b *Buffer) baz() { // ERROR "\(\*Buffer\).baz b does not escape$"
- b.str1 = b.str1[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment to b.str1$"
- b.str1 = b.str2[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment to b.str1$"
+ b.str1 = b.str1[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment in b.str1 = b.str1\[1:2\]$"
+ b.str1 = b.str2[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment in b.str1 = b.str2\[1:2\]$"
 }
 
 func (b *Buffer) bat() { // ERROR "leaking param content: b$"
@@ -1629,8 +1629,8 @@ func (b *Buffer) bat() { // ERROR "leaking param content: b$"
 }
 
 func quux(sp *string, bp *[]byte) { // ERROR "quux bp does not escape$" "quux sp does not escape$"
- *sp = (*sp)[1:2] // ERROR "quux ignoring self-assignment to \*sp$"
- *bp = (*bp)[1:2] // ERROR "quux ignoring self-assignment to \*bp$"
+ *sp = (*sp)[1:2] // ERROR "quux ignoring self-assignment in \*sp = \(\*sp\)\[1:2\]$"
+ *bp = (*bp)[1:2] // ERROR "quux ignoring self-assignment in \*bp = \(\*bp\)\[1:2\]$"
 }
 
 type StructWithString struct {

diff --git a/test/escape2n.go b/test/escape2n.go
@@ -1602,24 +1602,24 @@ type Buffer struct {
 }
 
 func (b *Buffer) foo() { // ERROR "\(\*Buffer\).foo b does not escape$"
- b.buf1 = b.buf1[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
- b.buf1 = b.buf1[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
- b.buf1 = b.buf2[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
- b.buf1 = b.buf2[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment to b.buf1$"
+ b.buf1 = b.buf1[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf1\[1:2\]$"
+ b.buf1 = b.buf1[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf1\[1:2:3\]$"
+ b.buf1 = b.buf2[1:2] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf2\[1:2\]$"
+ b.buf1 = b.buf2[1:2:3] // ERROR "\(\*Buffer\).foo ignoring self-assignment in b.buf1 = b.buf2\[1:2:3\]$"
 }
 
 func (b *Buffer) bar() { // ERROR "leaking param: b$"
  b.buf1 = b.arr[1:2] // ERROR "b.arr escapes to heap$"
 }
 
 func (b *Buffer) arrayPtr() { // ERROR "\(\*Buffer\).arrayPtr b does not escape"
- b.buf1 = b.arrPtr[1:2] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment to b.buf1"
- b.buf1 = b.arrPtr[1:2:3] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment to b.buf1"
+ b.buf1 = b.arrPtr[1:2] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment in b.buf1 = b.arrPtr\[1:2\]$"
+ b.buf1 = b.arrPtr[1:2:3] // ERROR "\(\*Buffer\).arrayPtr ignoring self-assignment in b.buf1 = b.arrPtr\[1:2:3\]$"
 }
 
 func (b *Buffer) baz() { // ERROR "\(\*Buffer\).baz b does not escape$"
- b.str1 = b.str1[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment to b.str1$"
- b.str1 = b.str2[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment to b.str1$"
+ b.str1 = b.str1[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment in b.str1 = b.str1\[1:2\]$"
+ b.str1 = b.str2[1:2] // ERROR "\(\*Buffer\).baz ignoring self-assignment in b.str1 = b.str2\[1:2\]$"
 }
 
 func (b *Buffer) bat() { // ERROR "leaking param content: b$"
@@ -1629,8 +1629,8 @@ func (b *Buffer) bat() { // ERROR "leaking param content: b$"
 }
 
 func quux(sp *string, bp *[]byte) { // ERROR "quux bp does not escape$" "quux sp does not escape$"
- *sp = (*sp)[1:2] // ERROR "quux ignoring self-assignment to \*sp$"
- *bp = (*bp)[1:2] // ERROR "quux ignoring self-assignment to \*bp$"
+ *sp = (*sp)[1:2] // ERROR "quux ignoring self-assignment in \*sp = \(\*sp\)\[1:2\]$"
+ *bp = (*bp)[1:2] // ERROR "quux ignoring self-assignment in \*bp = \(\*bp\)\[1:2\]$"
 }
 
 type StructWithString struct {