Support stdlib analyzers with nogo.

This immediately revealed an escape analysis violation (!), where
the sync.Map was being used in a context that escapes were not
allowed. This is a relatively minor fix and is included.

PiperOrigin-RevId: 328611237

4 files changed, 9 insertions, 33 deletions

diff --git a/tools/checkescape/BUILD b/tools/checkescape/BUILD
index b8c3ddf44..6273aa779 100644
--- a/tools/checkescape/BUILD
+++ b/tools/checkescape/BUILD
@@ -8,7 +8,7 @@ go_library(
     nogo = False,
     visibility = ["//tools/nogo:__subpackages__"],
     deps = [
-        "//tools/nogo/data",
+        "//tools/nogo/dump",
         "@org_golang_x_tools//go/analysis:go_tool_library",
         "@org_golang_x_tools//go/analysis/passes/buildssa:go_tool_library",
         "@org_golang_x_tools//go/ssa:go_tool_library",
diff --git a/tools/checkescape/checkescape.go b/tools/checkescape/checkescape.go
index f8def4823..aab3c36a1 100644
--- a/tools/checkescape/checkescape.go
+++ b/tools/checkescape/checkescape.go
@@ -66,7 +66,6 @@ import (
 	"go/token"
 	"go/types"
 	"io"
-	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -74,7 +73,7 @@ import (
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/buildssa"
 	"golang.org/x/tools/go/ssa"
-	"gvisor.dev/gvisor/tools/nogo/data"
+	"gvisor.dev/gvisor/tools/nogo/dump"
 )
 
 const (
@@ -256,15 +255,14 @@ func (ec *EscapeCount) Record(reason EscapeReason) bool {
 // used only to remove false positives for escape analysis. The call will be
 // elided if escape analysis is able to put the object on the heap exclusively.
 func loadObjdump() (map[LinePosition]string, error) {
-	f, err := os.Open(data.Objdump)
+	cmd, out, err := dump.Command()
 	if err != nil {
 		return nil, err
 	}
-	defer f.Close()
 
 	// Build the map.
 	m := make(map[LinePosition]string)
-	r := bufio.NewReader(f)
+	r := bufio.NewReader(out)
 	var (
 		lastField string
 		lastPos   LinePosition
@@ -329,6 +327,11 @@ func loadObjdump() (map[LinePosition]string, error) {
 		}
 	}
 
+	// Wait for the dump to finish.
+	if err := cmd.Wait(); err != nil {
+		return nil, err
+	}
+
 	return m, nil
 }
 
@@ -413,12 +416,6 @@ func run(pass *analysis.Pass) (interface{}, error) {
 					return escapes(unknownPackage, "no package", inst, ec)
 				}
 
-				// Atomic functions are instrinics. We can
-				// assume that they don't escape.
-				if x.Pkg.Pkg.Name() == "atomic" {
-					return nil
-				}
-
 				// Is this a local function? If yes, call the
 				// function to load the local function. The
 				// local escapes are the escapes found in the
diff --git a/tools/checkescape/test1/test1.go b/tools/checkescape/test1/test1.go
index 68d3f72cc..a1d36459f 100644
--- a/tools/checkescape/test1/test1.go
+++ b/tools/checkescape/test1/test1.go
@@ -17,7 +17,6 @@ package test1
 
 import (
 	"fmt"
-	"reflect"
 )
 
 // Interface is a generic interface.
@@ -163,20 +162,6 @@ func dynamicRec(f func()) {
 	Dynamic(f)
 }
 
-// +mustescape:local,unknown
-//go:noinline
-//go:nosplit
-func Unknown() {
-	_ = reflect.TypeOf((*Type)(nil)) // Does not actually escape.
-}
-
-// +mustescape:unknown
-//go:noinline
-//go:nosplit
-func unknownRec() {
-	Unknown()
-}
-
 //go:noinline
 //go:nosplit
 func internalFunc() {
diff --git a/tools/checkescape/test2/test2.go b/tools/checkescape/test2/test2.go
index 7fce3e3be..2d5865f47 100644
--- a/tools/checkescape/test2/test2.go
+++ b/tools/checkescape/test2/test2.go
@@ -81,12 +81,6 @@ func dynamicCrossPkg(f func()) {
 	test1.Dynamic(f)
 }
 
-// +mustescape:unknown
-//go:noinline
-func unknownCrossPkg() {
-	test1.Unknown()
-}
-
 // +mustescape:stack
 //go:noinline
 func splitCrosssPkt() {