test(verify): prove the riscv64 vector families through the link-parity kernel

Assisted-by: GLM 5.3 Flash

verify/goobj_link_vector_test.go

@@ -0,0 +1,56 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: BSD-3-Clause
+
+package verify
+
+import (
+	"os"
+	"os/exec"
+	"testing"
+)
+
+// goobjVectorMainSrc is the Go side of the vector regression.  The kernel
+// computes a signed byte checksum through the RVV load/store and arithmetic
+// families; main derives the same value in Go and panics on any divergence
+// before printing the deterministic line the baseline and the gasm-linked
+// binaries must agree on.
+const goobjVectorMainSrc = `package main
+
+func checksum(buf []byte, seed int64) int64
+
+func main() {
+	buf := []byte("gasm link parity vector kernel!")
+	total := int64(0)
+	for _, b := range buf {
+		total += int64(int8(b))
+	}
+	want := total*0x0101010101010101 ^ 0x5eed
+	if got := checksum(buf, 0x5eed); got != want {
+		panic("checksum")
+	}
+	println("ok", checksum(buf, 0x5eed))
+}
+`
+
+// TestGOOBJLinkRVVKernel proves the riscv64 vector families merged into the
+// encoder corpus are proven end to end: the kernel assembles by gasm into a
+// GOOBJ object, substitutes byte-wise into a real go build archive, relinks
+// with cmd/link and the linked binary computes the same checksum as the
+// toolchain-built one under qemu-user.  The reduction reads the live vl, so
+// the checksum holds for any hardware VLEN.
+func TestGOOBJLinkRVVKernel(t *testing.T) {
+	if testing.Short() {
+		t.Skip("builds the gasm binary and links Go programs")
+	}
+	if os.Getenv("GASM_LINK_PARITY") == "" {
+		t.Skip("deliberate verification: set GASM_LINK_PARITY=1 (just link-parity)")
+	}
+	goBin, err := exec.LookPath("go")
+	if err != nil {
+		t.Skip("no Go toolchain available")
+	}
+	gasmBin := buildLinkParityGasm(t, goBin)
+	t.Run("riscv64", func(t *testing.T) {
+		goobjLinkKernel(t, goBin, gasmBin, "riscv64", "linkvec_riscv64.s", goobjVectorMainSrc)
+	})
+}