diff --git a/pkg/procid/BUILD b/pkg/procid/BUILD
index 2838b5aca..9124b5b05 100644
--- a/pkg/procid/BUILD
+++ b/pkg/procid/BUILD
@@ -1,13 +1,29 @@
-load("//tools:defs.bzl", "go_library", "go_test")
+load("//tools:defs.bzl", "arch_genrule", "go_library", "go_test", "select_arch")
+load("//tools/nogo:defs.bzl", "nogo_facts")
 
 package(licenses = ["notice"])
 
+nogo_facts(
+    name = "procid_impl",
+    srcs = ["procid.go"],
+    output = "procid_impl.s",
+    template = select_arch(
+        amd64 = "procid_amd64.s",
+        arm64 = "procid_arm64.s",
+    ),
+)
+
+arch_genrule(
+    name = "procid_impl_arch",
+    src = ":procid_impl",
+    template = "procid_impl_%s.s",
+)
+
 go_library(
     name = "procid",
     srcs = [
         "procid.go",
-        "procid_amd64.s",
-        "procid_arm64.s",
+        ":procid_impl_arch",
     ],
     visibility = ["//visibility:public"],
 )
diff --git a/pkg/procid/procid.go b/pkg/procid/procid.go
index e0d42819d..55a16a80a 100644
--- a/pkg/procid/procid.go
+++ b/pkg/procid/procid.go
@@ -12,12 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build go1.1
-// +build go1.1
-
 // Package procid provides a way to get the current system thread identifier.
 package procid
 
+import (
+	"runtime"
+)
+
+// Dummy references for facts.
+const _ = runtime.Compiler
+
 // Current returns the current system thread identifier.
 //
 // Precondition: This should only be called with the runtime OS thread locked.
diff --git a/pkg/procid/procid_amd64.s b/pkg/procid/procid_amd64.s
index 54a2f6162..7173ddf1b 100644
--- a/pkg/procid/procid_amd64.s
+++ b/pkg/procid/procid_amd64.s
@@ -12,22 +12,19 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build amd64 && go1.8 && !go1.21 && go1.1
-// +build amd64,go1.8,!go1.21,go1.1
-
-// //go:linkname directives type-checked by checklinkname. Any other
-// non-linkname assumptions outside the Go 1 compatibility guarantee should
-// have an accompanied vet check or version guard build tag.
+//go:build amd64
+// +build amd64
 
 #include "textflag.h"
 
+#define M_OFFSET {{ .import.runtime.g.m.Offset }}
+#define PROCID_OFFSET {{ .import.runtime.m.procid.Offset }}
+
 TEXT ·Current(SB),NOSPLIT,$0-8
-	// The offset specified here is the m_procid offset for Go1.8+.
-	// Changes to this offset should be caught by the tests, and major
-	// version changes require an explicit tag change above.
+	// procid is in getg().m.procid.
 	MOVQ TLS, AX
 	MOVQ 0(AX)(TLS*1), AX
-	MOVQ 48(AX), AX // g_m (may change in future versions)
-	MOVQ 72(AX), AX // m_procid (may change in future versions)
+	MOVQ M_OFFSET(AX), AX // gp.m
+	MOVQ PROCID_OFFSET(AX), AX // mp.procid
 	MOVQ AX, ret+0(FP)
 	RET
diff --git a/pkg/procid/procid_arm64.s b/pkg/procid/procid_arm64.s
index 78736df39..22e23ef5b 100644
--- a/pkg/procid/procid_arm64.s
+++ b/pkg/procid/procid_arm64.s
@@ -12,21 +12,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build arm64 && go1.8 && !go1.21 && go1.1
-// +build arm64,go1.8,!go1.21,go1.1
-
-// //go:linkname directives type-checked by checklinkname. Any other
-// non-linkname assumptions outside the Go 1 compatibility guarantee should
-// have an accompanied vet check or version guard build tag.
+//go:build arm64
+// +build arm64
 
 #include "textflag.h"
 
+#define M_OFFSET {{ .import.runtime.g.m.Offset }}
+#define PROCID_OFFSET {{ .import.runtime.m.procid.Offset }}
+
 TEXT ·Current(SB),NOSPLIT,$0-8
-	// The offset specified here is the m_procid offset for Go1.8+.
-	// Changes to this offset should be caught by the tests, and major
-	// version changes require an explicit tag change above.
+	// procid is in getg().m.procid.
 	MOVD g, R0      // g
-	MOVD 48(R0), R0 // g_m (may change in future versions)
-	MOVD 72(R0), R0 // m_procid (may change in future versions)
+	MOVD M_OFFSET(R0), R0 // gp.m
+	MOVD PROCID_OFFSET(R0), R0 // mp.procid
 	MOVD R0, ret+0(FP)
 	RET
diff --git a/tools/nogo/facts/facts.go b/tools/nogo/facts/facts.go
index 7de3a1edc..2578431d5 100644
--- a/tools/nogo/facts/facts.go
+++ b/tools/nogo/facts/facts.go
@@ -230,6 +230,13 @@ func (b *Bundle) Package(pkg *types.Package) (*Package, error) {
 		return facts, nil
 	}
 
+	if b.reader == nil {
+		// Nothing available.
+		//
+		// N.B. some bundles contain only cached packages.
+		return nil, nil
+	}
+
 	// Find based on the reader.
 	for _, f := range b.reader.File {
 		if f.Name != pkg.Path() {
@@ -368,6 +375,9 @@ func Resolve(pkg *types.Package, localFacts *Package, allFacts *Bundle, allFactN
 		if err != nil {
 			return nil, err
 		}
+		if importFacts == nil {
+			continue
+		}
 		r.walkScope(append(names, "import", importPkg.Name()), importPkg.Scope(), importFacts, allFactNames)
 	}
 	return r, nil