[release-branch.go1.26] cmd/compile: gate instrumentEnterExit on NoRaceFunc check

The NoRaceFunc flag is meant to suppress racefuncenter/racefuncexit
instrumentation for packages like internal/runtime/atomic. However,
instrumentEnterExit was set unconditionally when -race was enabled,
outside the NoRaceFunc guard. This caused generic functions from
NoRaceFunc packages (e.g. atomic.(*Pointer[T]).Store) to receive
racefuncenter calls when instantiated in other packages, leading to
a segfault during early runtime init before the race runtime is ready.

Move the instrumentEnterExit assignment inside the NoRaceFunc check
so both memory and enter/exit instrumentation are suppressed together.

Fixes #77799

Change-Id: Id03bb9c422d36e2e88ecdf165ad3b1a4700a935c
Reviewed-on: https://go-review.googlesource.com/c/go/+/748260
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
(cherry picked from commit 76222756d9674a41b01a11d123ce39a7b26eb7fc)
Reviewed-on: https://go-review.googlesource.com/c/go/+/752360
Reviewed-by: Derek Parker <parkerderek86@gmail.com>
Reviewed-by: Mark Freeman <markfreeman@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>

2 files changed, 42 insertions, 3 deletions

diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 17feb90df7..50b4e11f5e 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -340,9 +340,9 @@ func buildssa(fn *ir.Func, worker int, isPgoHot bool) *ssa.Func {
 	if base.Flag.Cfg.Instrumenting && fn.Pragma&ir.Norace == 0 && !fn.Linksym().ABIWrapper() {
 		if !base.Flag.Race || !objabi.LookupPkgSpecial(fn.Sym().Pkg.Path).NoRaceFunc {
 			s.instrumentMemory = true
-		}
-		if base.Flag.Race {
-			s.instrumentEnterExit = true
+			if base.Flag.Race {
+				s.instrumentEnterExit = true
+			}
 		}
 	}
 
diff --git a/src/cmd/compile/internal/test/fixedbugs_test.go b/src/cmd/compile/internal/test/fixedbugs_test.go
index b6d3e248ad..4730a21f34 100644
--- a/src/cmd/compile/internal/test/fixedbugs_test.go
+++ b/src/cmd/compile/internal/test/fixedbugs_test.go
@@ -5,9 +5,11 @@
 package test
 
 import (
+	"internal/platform"
 	"internal/testenv"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 )
@@ -84,3 +86,40 @@ func Mod32(x uint32) uint32 {
 	return x % 3 // frontend rewrites it as HMUL with 2863311531, the LITERAL node has unknown Pos
 }
 `
+
+// Test that building and running a program with -race -gcflags='all=-N -l'
+// does not crash. This is a regression test for #77597 where generic functions
+// from NoRaceFunc packages (like internal/runtime/atomic) were incorrectly
+// getting racefuncenter/racefuncexit instrumentation when instantiated in
+// other packages with optimizations disabled.
+func TestIssue77597(t *testing.T) {
+	if !platform.RaceDetectorSupported(runtime.GOOS, runtime.GOARCH) {
+		t.Skipf("race detector not supported on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+	testenv.MustHaveGoBuild(t)
+	testenv.MustHaveGoRun(t)
+	testenv.MustHaveCGO(t)
+
+	dir := t.TempDir()
+	src := filepath.Join(dir, "main.go")
+	err := os.WriteFile(src, []byte(issue77597src), 0644)
+	if err != nil {
+		t.Fatalf("could not write file: %v", err)
+	}
+
+	cmd := testenv.Command(t, testenv.GoToolPath(t), "run", "-race", "-gcflags=all=-N -l", src)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("program failed: %v\n%s", err, out)
+	}
+}
+
+var issue77597src = `
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("OK")
+}
+`