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[dev.typeparams] cmd/compile: skip escape analysis diagnostics for wrappers

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This CL changes escape analysis to skip reporting diagnostics (at
least for parameter tagging) for generated wrappers.

We're inconsistent about when/where wrappers are generated, which made
errorcheck tests of escape analysis unnecessarily brittle to changes
in wrapper generation. This CL addresses this making errorcheck tests
only care about tagging of the actual functions themselves, not the
wrappers too.

Change-Id: Ia1a0b9dabee4d4162b05647f871db03b032c945a
Reviewed-on: https://go-review.googlesource.com/c/go/+/330689
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Matthew Dempsky 2021-06-24 09:07:52 -07:00
parent b55cc6687d
commit df00abc61b
2 changed files with 12 additions and 7 deletions
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17
src/cmd/compile/internal/escape/escape.go
View file

@ -365,6 +365,11 @@ func (b *batch) paramTag(fn *ir.Func, narg int, f *types.Field) string {
return fmt.Sprintf("arg#%d", narg) return fmt.Sprintf("arg#%d", narg)
} }
// Only report diagnostics for user code;
// not for wrappers generated around them.
// TODO(mdempsky): Generalize this.
diagnose := base.Flag.LowerM != 0 && !(fn.Wrapper() || fn.Dupok())
if len(fn.Body) == 0 { if len(fn.Body) == 0 {
// Assume that uintptr arguments must be held live across the call. // Assume that uintptr arguments must be held live across the call.
// This is most important for syscall.Syscall. // This is most important for syscall.Syscall.
@ -375,7 +380,7 @@ func (b *batch) paramTag(fn *ir.Func, narg int, f *types.Field) string {
fn.Pragma |= ir.UintptrKeepAlive fn.Pragma |= ir.UintptrKeepAlive
if f.Type.IsUintptr() { if f.Type.IsUintptr() {
if base.Flag.LowerM != 0 { if diagnose {
base.WarnfAt(f.Pos, "assuming %v is unsafe uintptr", name()) base.WarnfAt(f.Pos, "assuming %v is unsafe uintptr", name())
} }
return "" return ""
@ -390,11 +395,11 @@ func (b *batch) paramTag(fn *ir.Func, narg int, f *types.Field) string {
// External functions are assumed unsafe, unless // External functions are assumed unsafe, unless
// //go:noescape is given before the declaration. // //go:noescape is given before the declaration.
if fn.Pragma&ir.Noescape != 0 { if fn.Pragma&ir.Noescape != 0 {
if base.Flag.LowerM != 0 && f.Sym != nil { if diagnose && f.Sym != nil {
base.WarnfAt(f.Pos, "%v does not escape", name()) base.WarnfAt(f.Pos, "%v does not escape", name())
} }
} else { } else {
if base.Flag.LowerM != 0 && f.Sym != nil { if diagnose && f.Sym != nil {
base.WarnfAt(f.Pos, "leaking param: %v", name()) base.WarnfAt(f.Pos, "leaking param: %v", name())
} }
esc.AddHeap(0) esc.AddHeap(0)
@ -407,14 +412,14 @@ func (b *batch) paramTag(fn *ir.Func, narg int, f *types.Field) string {
fn.Pragma |= ir.UintptrKeepAlive fn.Pragma |= ir.UintptrKeepAlive
if f.Type.IsUintptr() { if f.Type.IsUintptr() {
if base.Flag.LowerM != 0 { if diagnose {
base.WarnfAt(f.Pos, "marking %v as escaping uintptr", name()) base.WarnfAt(f.Pos, "marking %v as escaping uintptr", name())
} }
return "" return ""
} }
if f.IsDDD() && f.Type.Elem().IsUintptr() { if f.IsDDD() && f.Type.Elem().IsUintptr() {
// final argument is ...uintptr. // final argument is ...uintptr.
if base.Flag.LowerM != 0 { if diagnose {
base.WarnfAt(f.Pos, "marking %v as escaping ...uintptr", name()) base.WarnfAt(f.Pos, "marking %v as escaping ...uintptr", name())
} }
return "" return ""
@ -436,7 +441,7 @@ func (b *batch) paramTag(fn *ir.Func, narg int, f *types.Field) string {
esc := loc.paramEsc esc := loc.paramEsc
esc.Optimize() esc.Optimize()
if base.Flag.LowerM != 0 && !loc.escapes { if diagnose && !loc.escapes {
if esc.Empty() { if esc.Empty() {
base.WarnfAt(f.Pos, "%v does not escape", name()) base.WarnfAt(f.Pos, "%v does not escape", name())
} }

2
test/uintptrescapes2.go
View file

@ -30,7 +30,7 @@ type T struct{}
func (T) M1(a uintptr) {} // ERROR "escaping uintptr" func (T) M1(a uintptr) {} // ERROR "escaping uintptr"
//go:uintptrescapes //go:uintptrescapes
func (T) M2(a ...uintptr) {} // ERROR "escaping ...uintptr" "leaking param: a" func (T) M2(a ...uintptr) {} // ERROR "escaping ...uintptr"
func TestF1() { func TestF1() {
var t int // ERROR "moved to heap" var t int // ERROR "moved to heap"