cmd/compile: skip escape analysis diagnostics for OADDR

For most nodes (e.g., OPTRLIT, OMAKESLICE, OCONVIFACE), escape
analysis prints "escapes to heap" or "does not escape" to indicate
whether that node's allocation can be heap or stack allocated.

These messages are also emitted for OADDR, even though OADDR does not
actually allocate anything itself. Moreover, it's redundant because
escape analysis already prints "moved to heap" diagnostics when an
OADDR node like "&x" causes x to require heap allocation.

Because OADDR nodes don't allocate memory, my escape analysis rewrite
doesn't naturally emit the "escapes to heap" / "does not escape"
diagnostics for them. It's also non-trivial to replicate the exact
semantics esc.go uses for OADDR.

Since there are so many of these messages, I'm disabling them in this
CL by themselves. I modified esc.go to suppress the Warnl calls
without any other behavior changes, and then used a shell script to
automatically remove any ERROR messages mentioned by run.go in
"missing error" or "no match for" lines.

Fixes #16300.
Updates #23109.

Change-Id: I3993e2743c3ff83ccd0893f4e73b366ff8871a57
Reviewed-on: https://go-review.googlesource.com/c/go/+/170319
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/test/escape4.go b/test/escape4.go
index 0fe3305397..a4a9c14a3e 100644
--- a/test/escape4.go
+++ b/test/escape4.go
@@ -12,22 +12,22 @@ package foo
 var p *int
 
 func alloc(x int) *int { // ERROR "can inline alloc" "moved to heap: x"
-	return &x // ERROR "&x escapes to heap"
+	return &x
 }
 
 var f func()
 
 func f1() {
-	p = alloc(2) // ERROR "inlining call to alloc" "&x escapes to heap" "moved to heap: x"
+	p = alloc(2) // ERROR "inlining call to alloc" "moved to heap: x"
 
 	// Escape analysis used to miss inlined code in closures.
 
 	func() { // ERROR "can inline f1.func1"
 		p = alloc(3) // ERROR "inlining call to alloc"
-	}() // ERROR "inlining call to f1.func1" "inlining call to alloc" "&x escapes to heap" "moved to heap: x"
+	}() // ERROR "inlining call to f1.func1" "inlining call to alloc" "moved to heap: x"
 
 	f = func() { // ERROR "func literal escapes to heap" "can inline f1.func2"
-		p = alloc(3) // ERROR "inlining call to alloc" "&x escapes to heap" "moved to heap: x"
+		p = alloc(3) // ERROR "inlining call to alloc" "moved to heap: x"
 	}
 	f()
 }
@@ -43,7 +43,7 @@ func f5() *byte {
 		x [1]byte
 	}
 	t := new(T)    // ERROR "new.T. escapes to heap"
-	return &t.x[0] // ERROR "&t.x.0. escapes to heap"
+	return &t.x[0]
 }
 
 func f6() *byte {
@@ -53,5 +53,5 @@ func f6() *byte {
 		}
 	}
 	t := new(T)   // ERROR "new.T. escapes to heap"
-	return &t.x.y // ERROR "&t.x.y escapes to heap"
+	return &t.x.y
 }