63 lines
1.9 KiB
Go
63 lines
1.9 KiB
Go
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// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: BSD-3-Clause
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package verify
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import (
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"os"
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"os/exec"
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"testing"
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)
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// goobjFoldMainSrc is the Go side of the SSE regression. The kernel
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// XOR-folds 16-byte blocks and sums the tail bytes through the amd64 SSE
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// families; main derives the same value in Go and panics on any divergence
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// before printing the deterministic line the baseline and the gasm-linked
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// binaries must agree on.
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const goobjFoldMainSrc = `package main
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import "encoding/binary"
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func fold(buf []byte, seed uint64) uint64
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func main() {
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buf := []byte("gasm link parity vector kernel! 0123456789abcdef tail")
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low, high := uint64(0), uint64(0)
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for i := 0; i+16 <= len(buf); i += 16 {
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low ^= binary.LittleEndian.Uint64(buf[i:])
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high ^= binary.LittleEndian.Uint64(buf[i+8:])
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}
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tail := uint64(0)
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for _, b := range buf[len(buf)-len(buf)%16:] {
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tail += uint64(b)
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}
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const k = 0x9e3779b97f4a7c15
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want := (low + high + tail) * k ^ 0xabcdef
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if got := fold(buf, 0xabcdef); got != want {
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panic("fold")
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}
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println("ok", fold(buf, 0xabcdef))
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}
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`
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// TestGOOBJLinkFoldKernel proves the amd64 SSE families are proven end to
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// end: the kernel assembles by gasm into a GOOBJ object, substitutes
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// byte-wise into a real go build archive, relinks with cmd/link and the
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// linked binary computes the same fold as the toolchain-built one, run
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// natively on amd64 hosts.
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func TestGOOBJLinkFoldKernel(t *testing.T) {
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if testing.Short() {
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t.Skip("builds the gasm binary and links Go programs")
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}
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if os.Getenv("GASM_LINK_PARITY") == "" {
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t.Skip("deliberate verification: set GASM_LINK_PARITY=1 (just link-parity)")
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}
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goBin, err := exec.LookPath("go")
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if err != nil {
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t.Skip("no Go toolchain available")
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}
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gasmBin := buildLinkParityGasm(t, goBin)
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t.Run("amd64", func(t *testing.T) {
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goobjLinkKernel(t, goBin, gasmBin, "amd64", "linkfold_amd64.s", goobjFoldMainSrc)
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})
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}
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