cmd/compile: trim more unnecessary escape analysis messages

"leaking closure reference" is redundant for similar reasons as "&x
escapes to heap" for OADDR nodes: the reference itself does not
allocate, and we already report when the referenced variable is moved
to heap.

"mark escaped content" is redundant with "leaking param content".

Updates #23109.

Change-Id: I1ab599cb1e8434f1918dd80596a70cba7dc8a0cf
Reviewed-on: https://go-review.googlesource.com/c/go/+/170321
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/esc.go

@@ -1837,10 +1837,6 @@ func (e *EscState) escwalkBody(level Level, dst *Node, src *Node, step *EscStep,
 		src.Op == ONAME && src.Class() == PPARAM && src.Esc&EscMask < EscHeap &&
 		level.int() > 0 {
 		src.Esc = escMax(EscContentEscapes|src.Esc, EscNone)
-		if Debug['m'] != 0 {
-			Warnl(src.Pos, "mark escaped content: %S", src)
-			step.describe(src)
-		}
 	}
 
 	leaks = level.int() <= 0 && level.guaranteedDereference() <= 0 && dstE.Loopdepth < modSrcLoopdepth
@@ -1880,10 +1876,6 @@ func (e *EscState) escwalkBody(level Level, dst *Node, src *Node, step *EscStep,
 		// Treat a captured closure variable as equivalent to the
 		// original variable.
 		if src.IsClosureVar() {
-			if leaks && Debug['m'] != 0 {
-				Warnl(src.Pos, "leaking closure reference %S", src)
-				step.describe(src)
-			}
 			e.escwalk(level, dst, src.Name.Defn, e.stepWalk(dst, src.Name.Defn, "closure-var", step))
 		}
 

test/escape2.go

@@ -1186,7 +1186,7 @@ func foo124(x **int) { // ERROR "foo124 x does not escape$"
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo124 func literal does not escape$"
-		*x = p // ERROR "leaking closure reference p$"
+		*x = p
 	}()
 }
 
@@ -1194,7 +1194,7 @@ func foo125(ch chan *int) { // ERROR "foo125 ch does not escape$"
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo125 func literal does not escape$"
-		ch <- p // ERROR "leaking closure reference p$"
+		ch <- p
 	}()
 }
 
@@ -1204,7 +1204,7 @@ func foo126() {
 		// loopdepth 1
 		var i int // ERROR "moved to heap: i$"
 		func() {  // ERROR "foo126 func literal does not escape$"
-			px = &i // ERROR "leaking closure reference i"
+			px = &i
 		}()
 	}
 	_ = px
@@ -1230,9 +1230,9 @@ func foo129() {
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo129 func literal does not escape$"
-		q := p   // ERROR "leaking closure reference p$"
+		q := p
 		func() { // ERROR "foo129.func1 func literal does not escape$"
-			r := q // ERROR "leaking closure reference q$"
+			r := q
 			px = r
 		}()
 	}()
@@ -1242,7 +1242,7 @@ func foo130() {
 	for {
 		var i int // ERROR "moved to heap: i$"
 		func() {  // ERROR "foo130 func literal does not escape$"
-			px = &i // ERROR "leaking closure reference i$"
+			px = &i
 		}()
 	}
 }
@@ -1250,21 +1250,21 @@ func foo130() {
 func foo131() {
 	var i int // ERROR "moved to heap: i$"
 	func() {  // ERROR "foo131 func literal does not escape$"
-		px = &i // ERROR "leaking closure reference i$"
+		px = &i
 	}()
 }
 
 func foo132() {
 	var i int   // ERROR "moved to heap: i$"
 	go func() { // ERROR "func literal escapes to heap$"
-		px = &i // ERROR "leaking closure reference i$"
+		px = &i
 	}()
 }
 
 func foo133() {
 	var i int      // ERROR "moved to heap: i$"
 	defer func() { // ERROR "foo133 func literal does not escape$"
-		px = &i // ERROR "leaking closure reference i$"
+		px = &i
 	}()
 }
 
@@ -1296,9 +1296,9 @@ func foo136() {
 	var i int   // ERROR "moved to heap: i$"
 	p := &i
 	go func() { // ERROR "func literal escapes to heap$"
-		q := p   // ERROR "leaking closure reference p$"
+		q := p
 		func() { // ERROR "foo136.func1 func literal does not escape$"
-			r := q // ERROR "leaking closure reference q$"
+			r := q
 			px = r
 		}()
 	}()
@@ -1308,7 +1308,7 @@ func foo137() {
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo137 func literal does not escape$"
-		q := p      // ERROR "leaking closure reference p$"
+		q := p
 		go func() { // ERROR "func literal escapes to heap$"
 			r := q
 			_ = r

test/escape2n.go

@@ -1186,7 +1186,7 @@ func foo124(x **int) { // ERROR "foo124 x does not escape$"
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo124 func literal does not escape$"
-		*x = p // ERROR "leaking closure reference p$"
+		*x = p
 	}()
 }
 
@@ -1194,7 +1194,7 @@ func foo125(ch chan *int) { // ERROR "foo125 ch does not escape$"
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo125 func literal does not escape$"
-		ch <- p // ERROR "leaking closure reference p$"
+		ch <- p
 	}()
 }
 
@@ -1204,7 +1204,7 @@ func foo126() {
 		// loopdepth 1
 		var i int // ERROR "moved to heap: i$"
 		func() {  // ERROR "foo126 func literal does not escape$"
-			px = &i // ERROR "leaking closure reference i"
+			px = &i
 		}()
 	}
 	_ = px
@@ -1230,9 +1230,9 @@ func foo129() {
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo129 func literal does not escape$"
-		q := p   // ERROR "leaking closure reference p$"
+		q := p
 		func() { // ERROR "foo129.func1 func literal does not escape$"
-			r := q // ERROR "leaking closure reference q$"
+			r := q
 			px = r
 		}()
 	}()
@@ -1242,7 +1242,7 @@ func foo130() {
 	for {
 		var i int // ERROR "moved to heap: i$"
 		func() {  // ERROR "foo130 func literal does not escape$"
-			px = &i // ERROR "leaking closure reference i$"
+			px = &i
 		}()
 	}
 }
@@ -1250,21 +1250,21 @@ func foo130() {
 func foo131() {
 	var i int // ERROR "moved to heap: i$"
 	func() {  // ERROR "foo131 func literal does not escape$"
-		px = &i // ERROR "leaking closure reference i$"
+		px = &i
 	}()
 }
 
 func foo132() {
 	var i int   // ERROR "moved to heap: i$"
 	go func() { // ERROR "func literal escapes to heap$"
-		px = &i // ERROR "leaking closure reference i$"
+		px = &i
 	}()
 }
 
 func foo133() {
 	var i int      // ERROR "moved to heap: i$"
 	defer func() { // ERROR "foo133 func literal does not escape$"
-		px = &i // ERROR "leaking closure reference i$"
+		px = &i
 	}()
 }
 
@@ -1296,9 +1296,9 @@ func foo136() {
 	var i int   // ERROR "moved to heap: i$"
 	p := &i
 	go func() { // ERROR "func literal escapes to heap$"
-		q := p   // ERROR "leaking closure reference p$"
+		q := p
 		func() { // ERROR "foo136.func1 func literal does not escape$"
-			r := q // ERROR "leaking closure reference q$"
+			r := q
 			px = r
 		}()
 	}()
@@ -1308,7 +1308,7 @@ func foo137() {
 	var i int // ERROR "moved to heap: i$"
 	p := &i
 	func() {  // ERROR "foo137 func literal does not escape$"
-		q := p      // ERROR "leaking closure reference p$"
+		q := p
 		go func() { // ERROR "func literal escapes to heap$"
 			r := q
 			_ = r

test/escape_array.go

@@ -26,7 +26,7 @@ func bff(a, b *string) U { // ERROR "leaking param: a to result ~r2 level=0$" "l
 
 func tbff1() *string {
 	a := "cat"
-	b := "dog"       // ERROR "moved to heap: b$"
+	b := "dog" // ERROR "moved to heap: b$"
 	u := bff(&a, &b)
 	_ = u[0]
 	return &b
@@ -34,8 +34,8 @@ func tbff1() *string {
 
 // BAD: need fine-grained analysis to track u[0] and u[1] differently.
 func tbff2() *string {
-	a := "cat"       // ERROR "moved to heap: a$"
-	b := "dog"       // ERROR "moved to heap: b$"
+	a := "cat" // ERROR "moved to heap: a$"
+	b := "dog" // ERROR "moved to heap: b$"
 	u := bff(&a, &b)
 	_ = u[0]
 	return u[1]
@@ -71,7 +71,7 @@ func fuo(x *U, y *U) *string { // ERROR "leaking param: x to result ~r2 level=1$
 // pointers stored in small array literals do not escape;
 // large array literals are heap allocated;
 // pointers stored in large array literals escape.
-func hugeLeaks1(x **string, y **string) { // ERROR "leaking param content: x" "hugeLeaks1 y does not escape" "mark escaped content: x"
+func hugeLeaks1(x **string, y **string) { // ERROR "leaking param content: x" "hugeLeaks1 y does not escape"
 	a := [10]*string{*y}
 	_ = a
 	// 4 x 4,000,000 exceeds MaxStackVarSize, therefore it must be heap allocated if pointers are 4 bytes or larger.