cmd/loopvec-toolexec: give the same archive on every build

.github/workflows/test.yml

@@ -61,8 +61,13 @@ jobs:
       - name: Test tsvc (amd64, SIMD)
         run: make tsvc-test
 
-      - name: Install qemu-user-static
-        run: sudo apt-get update && sudo apt-get install -y qemu-user-static
+      # ubuntu-26.04 has no qemu-user-static: qemu-user ships the static
+      # emulators there, without the -static names the Makefile runs.
+      - name: Install qemu-user
+        run: |
+          sudo apt-get update && sudo apt-get install -y qemu-user
+          command -v qemu-aarch64-static || sudo ln -s "$(command -v qemu-aarch64)" /usr/local/bin/qemu-aarch64-static
+          qemu-aarch64-static --version
 
       - name: Test tsvc (arm64, qemu)
         run: make tsvc-test-qemu-arm64

BUGS.md

@@ -2,11 +2,11 @@
 
 loopvec rewrites code to use `GOEXPERIMENT=simd`, which is new, so most of what it hits
 is in the Go toolchain. This file lists the Go issues that affect loopvec. "tip" means
-gotip, "1.27.1" is the release toolchain loopvec is tested against.
+gotip, "1.27.3" is the release toolchain loopvec is tested against.
 
 | Issue | Status | Affects | loopvec's answer |
 |---|---|---|---|
-| [#80657](https://github.com/golang/go/issues/80657) simd in a method: internal compiler error | fixed on tip (CL 839405), still crashes on 1.27.1 | `-methods` | methods are skipped unless `-methods` is passed |
+| [#80657](https://github.com/golang/go/issues/80657) simd in a method: internal compiler error | fixed on tip (CL 839405), still crashes on 1.27.3 | `-methods` | methods are skipped unless `-methods` is passed |
 | [#80835](https://github.com/golang/go/issues/80835) legacy SSE encodings in functions using simd cause AVX-SSE transition penalties | open, fix pending (CLs 825145, 825146, in tip) | speed of any scalar float code that runs after a rewritten loop, in the same function or another | none; the portable `simd` package has no `ClearAVXUpperBits` |
 | [#81844](https://github.com/golang/go/issues/81844) blank identifier parameters rejected | fixed on tip (CL 841145) | every rewrite of a function with a `_` parameter | the generated file renames them `_p0`, `_p1`, ... |
 | [#81845](https://github.com/golang/go/issues/81845) calls left unresolved when inlined into a package initializer | closed as a duplicate of [#80689](https://github.com/golang/go/issues/80689), which is open | loops in package-level `var x = func() {...}()` | not rewritten (the generated initializer fails to link), see `package_initializer_no_rewrite.txt` and `toolexec_package_initializer.txt` |
@@ -19,7 +19,7 @@ gotip, "1.27.1" is the release toolchain loopvec is tested against.
 
 A function with a receiver that contains simd code failed to compile with
 `internal compiler error: missing Types entry`. loopvec does not rewrite loops in methods
-by default; `-methods` turns it on. The fix is on tip. On 1.27.1 the crash is still there,
+by default; `-methods` turns it on. The fix is on tip. On 1.27.3 the crash is still there,
 and `flag_methods_ice.txt` pins it, so that test starts failing when the pinned toolchain
 gets the fix. Reported by someone else; the fix is [CL 839405](https://go.dev/cl/839405).
 

Makefile

@@ -1,4 +1,4 @@
-export GOTOOLCHAIN ?= go1.27.1
+export GOTOOLCHAIN ?= go1.27.3
 
 .DEFAULT_GOAL := build
 

cmd/loopvec-toolexec/compile.go

@@ -197,10 +197,17 @@ func tryRewrite(tool string, args []string) (out []string, ok bool) {
 		return nil, false
 	}
 
-	// A package and its test variant are compiled concurrently under the same
-	// import path, so every compile gets its own directory.
-	dir, err := os.MkdirTemp(b.dir, strings.NewReplacer("/", "_", ".", "_").Replace(c.pkg)+"-")
-	if err != nil {
+	// The rewritten files go in the compile's own object directory, where the
+	// go command writes the importcfg: a package and its test variant are
+	// compiled concurrently under the same import path, so each needs its own
+	// place, and the go command trims that directory from file names with
+	// -trimpath. The file names end up in the export data, so the archive must
+	// not depend on where the directory is: the go command can compile a
+	// package twice in one build (with PGO, once for each test binary) and use
+	// one archive to compile its importers and the other to link them, and the
+	// linker rejects two archives that differ.
+	dir := filepath.Join(filepath.Dir(args[c.importcfg]), "loopvec")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
 		return nil, false
 	}
 	newArgs := append([]string(nil), args...)

go.mod

@@ -3,7 +3,7 @@ module github.com/mauri870/loopvec
 go 1.27.1
 
 require (
-	golang.org/x/tools v0.51.0
+	golang.org/x/tools v0.52.1-0.20261030190145-0f433775b36d
 	rsc.io/script v0.0.2
 )
 
@@ -207,10 +207,10 @@ require (
 	go.uber.org/zap v1.27.0 // indirect
 	go.yaml.in/yaml/v3 v3.0.5 // indirect
 	golang.org/x/exp/typeparams v0.0.0-20260811152304-ee035b5b010f // indirect
-	golang.org/x/mod v0.41.0 // indirect
-	golang.org/x/sync v0.23.0 // indirect
-	golang.org/x/sys v0.48.0 // indirect
-	golang.org/x/telemetry v0.0.0-20260924152758-ed294f943157 // indirect
+	golang.org/x/mod v0.42.0 // indirect
+	golang.org/x/sync v0.24.0 // indirect
+	golang.org/x/sys v0.49.0 // indirect
+	golang.org/x/telemetry v0.0.0-20261009151841-97e8ea77aa2a // indirect
 	golang.org/x/text v0.41.0 // indirect
 	google.golang.org/protobuf v1.36.12 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect

go.sum

@@ -688,8 +688,8 @@ golang.org/x/mod v0.4.1/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3/go.mod h1:3p9vT2HGsQu2K1YbXdKPJLVgG5VJdoTa1poYQBtP1AY=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
-golang.org/x/mod v0.41.0 h1:qJmnOUb4YB+FsEuM3HcWucdZASCPGhsX6uljO6pog0c=
-golang.org/x/mod v0.41.0/go.mod h1:Ek9pY8RKWXwsWvd3rQiHYtMqkjSUV+s1Rj7j4H5Ur6o=
+golang.org/x/mod v0.42.0 h1:ICeL3t2L30ljSPHHxDnR4fqVcBt/zR2zJAb9juavmQg=
+golang.org/x/mod v0.42.0/go.mod h1:u5fzIrRInkL8MaO1cbRkUHT64v303YIT5KEqpNr7jRs=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@@ -724,8 +724,8 @@ golang.org/x/net v0.0.0-20210525063256-abc453219eb5/go.mod h1:9nx3DQGgdP8bBQD5qx
 golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
-golang.org/x/net v0.59.0 h1:5zfYln+w5XCxwrnMMJPufRgNoXEaGxl0wo5GqPXyues=
-golang.org/x/net v0.59.0/go.mod h1:2DA/G1UfVbCpQPeWTmMPGY7Cs2PkBkwu743bVX5PIVg=
+golang.org/x/net v0.61.0 h1:RR+6j/BTBCrggOLugxa+66R8FvoN6MHlzDlZIbN9YFw=
+golang.org/x/net v0.61.0/go.mod h1:WgDCOTH8iwtB66T4/GfI94AHo/hhdb7Hah9NDseQfiI=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -745,8 +745,8 @@ golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.23.0 h1:KameEIfc1IkluZyXWLn39Wd4tURc6GbCiISGiZm2bQk=
-golang.org/x/sync v0.23.0/go.mod h1:sUUOizhqBxiL6pEWpqNLUiaJn1ShEbZ6BBqskPbjZm0=
+golang.org/x/sync v0.24.0 h1:iqiDrGoDgyuvAKrhLQthUEzU/R378N78gXbBjxed7oA=
+golang.org/x/sync v0.24.0/go.mod h1:sUUOizhqBxiL6pEWpqNLUiaJn1ShEbZ6BBqskPbjZm0=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -790,10 +790,10 @@ golang.org/x/sys v0.0.0-20220114195835-da31bd327af9/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.48.0 h1:bbX/i/6MgT9BVLM9RT1thmxL04yeTAhbEz4SyadbXoo=
-golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
-golang.org/x/telemetry v0.0.0-20260924152758-ed294f943157 h1:DftxASHKl6JolFPqoN+2WrFO53JvkHwRXvFqf8gsivA=
-golang.org/x/telemetry v0.0.0-20260924152758-ed294f943157/go.mod h1:i+ivNqjDnTF3WTElsdk5g9V5DTSBYgdNo7xTU9SDwYA=
+golang.org/x/sys v0.49.0 h1:XbzkgYJHdqh/8m2Uu0W/dQv8nktxx4BFHp1M0gROTXA=
+golang.org/x/sys v0.49.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
+golang.org/x/telemetry v0.0.0-20261009151841-97e8ea77aa2a h1:wnveMBKHwx8/nIb8WYT5P9vtefdXOvIWxzycCkc5n6Q=
+golang.org/x/telemetry v0.0.0-20261009151841-97e8ea77aa2a/go.mod h1:i+ivNqjDnTF3WTElsdk5g9V5DTSBYgdNo7xTU9SDwYA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
@@ -857,8 +857,8 @@ golang.org/x/tools v0.1.1-0.20210302220138-2ac05c832e1a/go.mod h1:9bzcO0MWcOuT0t
 golang.org/x/tools v0.1.10/go.mod h1:Uh6Zz+xoGYZom868N8YTex3t7RhtHDBrE8Gzo9bV56E=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
-golang.org/x/tools v0.51.0 h1:k4Xc/1Om9jwkBJBo4NVLMSARBoWtK10mx+W5BnXCeAI=
-golang.org/x/tools v0.51.0/go.mod h1:9eEncMayCV6zRMGhR5eZEC2iBx98qWcF1HZ9Z7wJOoA=
+golang.org/x/tools v0.52.1-0.20261030190145-0f433775b36d h1:F5ot9G6RM6pgx3TTdKF6IZa2nocit4tcsrVQlq4Zh5w=
+golang.org/x/tools v0.52.1-0.20261030190145-0f433775b36d/go.mod h1:ItcP5UNaVGG+Yc4eIYmaFLNJ4soEopkx5Y2d4lcEurs=
 golang.org/x/tools/go/expect v0.1.1-deprecated h1:jpBZDwmgPhXsKZC6WhL20P4b/wmnpsEAGHaNy0n/rJM=
 golang.org/x/tools/go/expect v0.1.1-deprecated/go.mod h1:eihoPOH+FgIqa3FpoTwguz/bVUSGBlGQU67vpBeOrBY=
 golang.org/x/tools/go/packages/packagestest v0.1.1-deprecated h1:1h2MnaIAIXISqTFKdENegdpAgUXz6NrPEsbIeWaBRvM=

testdata/toolexec_reproducible.txt

@@ -0,0 +1,28 @@
+# The wrapper compiles rewritten files from a directory of its own, and their
+# names end up in the export data. Building the same package twice must still
+# give the same archive: the go command can compile a package twice in one build
+# (with PGO, once for each test binary that needs it), compile its importers
+# against one copy and link the other, and the linker rejects two copies that
+# differ.
+
+env GOEXPERIMENT=simd
+env LOOPVEC_TOOLEXEC_LOG=$WORK/log
+env GOCACHE=$WORK/gocache1
+exec go build -buildmode=archive -toolexec=$LOOPVEC_TOOLEXEC -o a1.a .
+env GOCACHE=$WORK/gocache2
+exec go build -buildmode=archive -toolexec=$LOOPVEC_TOOLEXEC -o a2.a .
+grep -count=2 '^rewrote 1 loop\(s\) in example\.com/lib$' log
+cmp a1.a a2.a
+
+-- go.mod --
+module example.com/lib
+
+go 1.27.1
+-- lib.go --
+package lib
+
+func Add(dst, a, b []float32) {
+	for i := range dst {
+		dst[i] = a[i] + b[i]
+	}
+}