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authorMichael Pratt <mpratt@google.com>2021-07-30 13:39:18 -0700
committergVisor bot <gvisor-bot@google.com>2021-07-30 13:42:15 -0700
commit62ea5c0a2212b9827f093551fc3da166facb9f0b (patch)
treee26283ab57a11a34202cc731da4270c53c418951 /pkg/gohacks/gohacks_unsafe.go
parent095b0d8348531b96f1b40885c00d6cd7f07ecf80 (diff)
checklinkname: rudimentary type-checking of linkname directives
This CL introduces a 'checklinkname' analyzer, which provides rudimentary type-checking that verifies that function signatures on the local and remote sides of //go:linkname directives match expected values. If the Go standard library changes the definitions of any of these function, checklinkname will flag the change as a finding, providing an error informing the gVisor team to adapt to the upstream changes. This allows us to eliminate the majority of gVisor's forward-looking negative build tags, as we can catch mismatches in testing [1]. The remaining forward-looking negative build tags are covering shared struct definitions, which I hope to add to checklinkname in a future CL. [1] Of course, semantics/requirements can change without the signature changing, so we still must be careful, but this covers the common case. PiperOrigin-RevId: 387873847
Diffstat (limited to 'pkg/gohacks/gohacks_unsafe.go')
-rw-r--r--pkg/gohacks/gohacks_unsafe.go8
1 files changed, 7 insertions, 1 deletions
diff --git a/pkg/gohacks/gohacks_unsafe.go b/pkg/gohacks/gohacks_unsafe.go
index 09fc14787..bd8ceba19 100644
--- a/pkg/gohacks/gohacks_unsafe.go
+++ b/pkg/gohacks/gohacks_unsafe.go
@@ -15,7 +15,13 @@
//go:build go1.13 && !go1.18
// +build go1.13,!go1.18
-// Check type signatures when updating Go version.
+// //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.
+
+// Check type signatures and Noescape when updating Go version.
+//
+// TODO(b/165820485): add these checks to checklinkname.
// Package gohacks contains utilities for subverting the Go compiler.
package gohacks