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 <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

diff --git a/src/cmd/compile/internal/gc/esc.go b/src/cmd/compile/internal/gc/esc.go
index ad4d11806c84d360f939af69989a0c2bd87bfa8b..145007f5e1bb6784a3c34fcc1fc4f0f76cdae02e 100644 (file)
--- 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
index 5c4c803249f6de9b14930dadceb13bd0c7f88dd2..a39291e85558de4b7f2c5863bb635c767efde164 100644 (file)
--- a/test/escape2.go
+++ b/test/escape2.go
@@ -1602,10 +1602,10 @@ 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$"
@@ -1613,13 +1613,13 @@ func (b *Buffer) bar() { // ERROR "leaking param: b$"
 }
 
 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
index 4b1ca1eab8b7b7fd2c7d298546e2130857404f6f..989cf18d35dbe57d3170e1acd27e993cdd8189e4 100644 (file)
--- a/test/escape2n.go
+++ b/test/escape2n.go
@@ -1602,10 +1602,10 @@ 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$"
@@ -1613,13 +1613,13 @@ func (b *Buffer) bar() { // ERROR "leaking param: b$"
 }
 
 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 {