Files
wasm2go/internal/gcasm/simdsplice_fuse_dot8_a64_test.go
f30ec292fd Support the wasm SIMD proposal with native asm lowering (arm64/amd64) (#40)
* Support the wasm SIMD proposal with native asm lowering (arm64/amd64)

One revision spanning the SIMD (0xfd v128) proposal end to end: SSA
representation, lowering, scalar reference helpers, and a gcasm asm
backend that turns the hot paths into native SIMD — measured on a
full llama.cpp build transpiled to pure Go, which this makes run at
V8-class speed (prompt eval beats V8 on arm64).

Frontend and SSA:
- v128 values are [2]uint64 pairs in little-endian lane order; pure
  ops lower to CSE-able helper calls, memory ops keep statement
  order, v128.const/shuffle ride as [2]uint64 aux. The full scalar
  helper set is the reference semantics (saturation, NaN
  propagation, round-to-even, swizzle OOB, shift masking).
- Exception handling lowers to plain branches instead of
  panic/recover — a check-and-branch after each may-raise call, a
  per-try dispatch block running the catch-clause chain — covering
  the C++-shaped patterns (multi-clause catch, delegate targets,
  rethrow depths) without runtime unwinding, so EH bodies stay
  eligible for the asm backend. This replaces the closure/recover
  lowering that #39 extended; its tests are retained unchanged.
- Giant functions outline into tractable units (whole loops
  included, packed u64 boundaries for v128 values), keeping gc
  compile times and register pressure sane on llama.cpp-sized
  modules.

gcasm backend:
- SIMD helper calls splice inline as native NEON/SSE instead of
  marshalled calls; v128 SSA values travel register-to-register in
  pair form. Call-tree windows fuse into single splices with region
  invariant hoisting, bounds-check coalescing, store sinks and
  scalar-chain internalization; whole countdown loops fuse with an
  in-splice unroll lane.
- Superinstruction selection inside fused regions: 8-bit dot
  patterns (SMULL+SADALP), SDOT for full 16-byte dots, FMUL by
  element, scale-lookup addressing, inlined integer division, the
  software fp32->fp16 idiom lowered to FCVT (both the table-gather
  and the packed store form), and ggml q8_0 row/column pairing via
  the traits nrows patch with an SMMLA 2x2 tile kernel.
- Runtime CPU-feature dispatch gates spliced bodies (dotprod on
  arm64, x86-64-v2 SSE on amd64); WASM2GO_FAST_MATH opts into
  raw-SDOT/FMLA/dual-accumulator forms that trade wasm bit-exactness
  for native-build-style rounding, validated by token-level
  equivalence against native llama.cpp.
- Guard-page linear memory eliminates per-access bounds checks;
  jump tables replace the compare tree for br_table.

Tooling and CI:
- WASM2GO_F16_TABLE asserts the address of ggml's runtime-built f16
  table; the transpiler warns when the asserted address matches no
  gather site (the address moves with every data-layout shift, and a
  stale assertion silently costs ~7% decode throughput).
- The coverage gate runs with -count=1: a cached package result
  merges incomplete coverage data into the -coverpkg profile,
  deflating the total by 10+ points depending on what the runner's
  restored cache contained — the gate must never consume cached
  results.
- Coverage threshold moves to 83% for the enlarged tree; transpile
  output is deterministic and outline rejections are explained in
  the build log.

Co-Authored-By: Claude Fable 5 <[email protected]>

* Replace environment-variable switches with typed Options; drop debug code

Configuration now flows through one channel: transpile.Options gains
OutlineMinValues, SIMDUnroll, FuseLoops, FuseLoopUnroll, F16TableAddr
and FastMath (with matching CLI flags), the gcasm backend receives
them as a Config threaded through ModuleOffsets, and no code path
branches on an environment variable anymore. Integrator entry points
(the wasmify protoc plugin, the CLI) convert their external
configuration into these options exactly once.

Deleted outright, per the no-env rule and because they were
diagnostics rather than build modes:
- every WASM2GO_NO_* kill switch and bisection knob (SSA pass
  disabling, fallback ranges, fuse-window caps, outline limits,
  inliner windows) — git history keeps them for the next hunt;
- every env-gated debug printer (fuse/inline/outline/nrc2/f16/SSA
  dumps and the near-miss tracers) and the capture-tree keepers;
- the dormant multi-exit loop structuring (opt-in, measured slower)
  and the SSA f32->f16 rewrite entry superseded by the gcasm
  peephole (its shared idiom matchers stay for the f16 store pass);
- the runtime WASM2GO_CPU_PORTABLE override in the generated CPU
  feature probes.

The nil-offsets error paths exposed by the threading get nil-safe
Config accessors, and the outline share/v128-min/inliner caps become
plain constants at their measured production values.

Behavior under default options is unchanged: transpiled output for
the non-SIMD and EH fixtures is byte-identical to the previous
commit, and the only SIMD-bundle difference is the removed env check
in the emitted cpufeat runtime files.

Co-Authored-By: Claude Fable 5 <[email protected]>

---------

Co-authored-by: Claude Fable 5 <[email protected]>
2026-08-08 23:28:14 +09:00

342 lines
12 KiB
Go

package gcasm
import (
"strings"
"testing"
"github.com/goccy/wasm2go/internal/simdfuse"
)
// fuseDot8Tree is the ggml integer-dot shape: two byte loads, both
// halves sign-extended, dotted per half and summed.
func fuseDot8Tree(extraRoot bool) *simdfuse.Tree {
load := func(scalar int) simdfuse.Node {
return simdfuse.Node{Op: "v128_load_rng", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgScalar, Index: scalar},
{Kind: simdfuse.ArgConst, Const: 0},
{Kind: simdfuse.ArgConst, Const: 0},
{Kind: simdfuse.ArgConst, Const: 16},
}}
}
t := &simdfuse.Tree{
Name: "simd_p_fxd8",
NumScalars: 2,
NeedsMem: true,
Nodes: []simdfuse.Node{
load(0),
load(1),
{Op: "i16x8_extend_low_i8x16_s", Args: []simdfuse.Arg{{Kind: simdfuse.ArgNode, Index: 0}}},
{Op: "i16x8_extend_low_i8x16_s", Args: []simdfuse.Arg{{Kind: simdfuse.ArgNode, Index: 1}}},
{Op: "i32x4_dot_i16x8_s", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgNode, Index: 2}, {Kind: simdfuse.ArgNode, Index: 3}}},
{Op: "i16x8_extend_high_i8x16_s", Args: []simdfuse.Arg{{Kind: simdfuse.ArgNode, Index: 0}}},
{Op: "i16x8_extend_high_i8x16_s", Args: []simdfuse.Arg{{Kind: simdfuse.ArgNode, Index: 1}}},
{Op: "i32x4_dot_i16x8_s", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgNode, Index: 5}, {Kind: simdfuse.ArgNode, Index: 6}}},
{Op: "i32x4_add", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgNode, Index: 4}, {Kind: simdfuse.ArgNode, Index: 7}}},
},
Roots: []int{8},
}
if extraRoot {
// An extend that is also a region result must survive the
// rewrite, which then leaves the whole shape alone.
t.Roots = []int{2, 8}
}
return t
}
func TestA64Dot8Rewrite(t *testing.T) {
// The portable twin keeps the smull/sadalp form (no SDOT upgrade),
// which is the shape this test pins.
tree := fuseDot8Tree(false)
rt := a64Dot8Rewrite(tree, true, false)
if rt == tree {
t.Fatal("eligible tree not rewritten")
}
if got := rt.Nodes[4].Op; got != a64OpDot8Low {
t.Errorf("node 4: got %q, want %q", got, a64OpDot8Low)
}
// The add-tree flattening turns the second dot into products-only
// and the summing add into a sadalp accumulation.
if got := rt.Nodes[7].Op; got != a64OpDot8MulHigh {
t.Errorf("node 7: got %q, want %q", got, a64OpDot8MulHigh)
}
if got := rt.Nodes[8].Op; got != a64OpDot8Acc {
t.Errorf("node 8: got %q, want %q", got, a64OpDot8Acc)
}
if args := rt.Nodes[8].Args; len(args) != 2 || args[0].Index != 4 || args[1].Index != 7 {
t.Errorf("node 8 args: %+v, want the dot and its products", rt.Nodes[8].Args)
}
for _, n := range []int{2, 3, 5, 6} {
if got := rt.Nodes[n].Op; got != a64OpElided {
t.Errorf("node %d: got %q, want elided", n, got)
}
}
for _, n := range []int{4, 7} {
args := rt.Nodes[n].Args
if len(args) != 2 || args[0].Index != 0 || args[1].Index != 1 ||
args[0].Kind != simdfuse.ArgNode || args[1].Kind != simdfuse.ArgNode {
t.Errorf("node %d args: %+v, want the byte loads", n, args)
}
}
// The original tree must be untouched (the amd64 splicer and the
// Go fallback body keep the literal shape).
if tree.Nodes[2].Op != "i16x8_extend_low_i8x16_s" {
t.Error("rewrite mutated the shared tree")
}
if same := a64Dot8Rewrite(fuseDot8Tree(true), false, false); same != nil && same.Nodes[2].Op != "i16x8_extend_low_i8x16_s" {
t.Error("root extend rewritten away")
}
}
// The (low, high) pair over the same byte loads collapses further
// into one full 16-byte SDOT at the chain tail.
func TestA64SdotRewrite(t *testing.T) {
tree := fuseDot8Tree(false)
rt := a64Dot8Rewrite(tree, false, false)
if rt == tree {
t.Fatal("eligible tree not rewritten")
}
for _, n := range []int{2, 3, 4, 5, 6, 7} {
if got := rt.Nodes[n].Op; got != a64OpElided {
t.Errorf("node %d: got %q, want elided", n, got)
}
}
if got := rt.Nodes[8].Op; got != a64OpSdot16 {
t.Errorf("node 8: got %q, want %q", got, a64OpSdot16)
}
if args := rt.Nodes[8].Args; len(args) != 2 || args[0].Index != 0 || args[1].Index != 1 ||
args[0].Kind != simdfuse.ArgNode || args[1].Kind != simdfuse.ArgNode {
t.Errorf("node 8 args: %+v, want the byte loads", rt.Nodes[8].Args)
}
if a64TreeHasSdot(fuseDot8Tree(false), false, false) != true {
t.Error("a64TreeHasSdot disagrees with the rewrite")
}
if a64TreeHasSdot(fuseDot8Tree(true), false, false) {
t.Error("a64TreeHasSdot true for the unrewritable root-extend shape")
}
}
// fuseDot8ChainTree extends the shape to two 16-byte chunks summed
// into one accumulator: dot(low0)+dot(high0)+dot(high1)+dot(low1),
// the ggml per-block order.
func fuseDot8ChainTree() *simdfuse.Tree {
load := func(scalar int, off int32) simdfuse.Node {
return simdfuse.Node{Op: "v128_load_rng", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgScalar, Index: scalar},
{Kind: simdfuse.ArgConst, Const: off},
{Kind: simdfuse.ArgConst, Const: 0},
{Kind: simdfuse.ArgConst, Const: 16},
}}
}
ext := func(op string, n int) simdfuse.Node {
return simdfuse.Node{Op: op, Args: []simdfuse.Arg{{Kind: simdfuse.ArgNode, Index: n}}}
}
dot := func(a, b int) simdfuse.Node {
return simdfuse.Node{Op: "i32x4_dot_i16x8_s", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgNode, Index: a}, {Kind: simdfuse.ArgNode, Index: b}}}
}
add := func(a, b int) simdfuse.Node {
return simdfuse.Node{Op: "i32x4_add", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgNode, Index: a}, {Kind: simdfuse.ArgNode, Index: b}}}
}
return &simdfuse.Tree{
Name: "simd_p_fxd8c",
NumScalars: 2,
NeedsMem: true,
Nodes: []simdfuse.Node{
load(0, 0), // 0
load(1, 0), // 1
ext("i16x8_extend_low_i8x16_s", 0), // 2
ext("i16x8_extend_low_i8x16_s", 1), // 3
dot(2, 3), // 4
ext("i16x8_extend_high_i8x16_s", 0), // 5
ext("i16x8_extend_high_i8x16_s", 1), // 6
dot(5, 6), // 7
add(4, 7), // 8
load(0, 16), // 9
load(1, 16), // 10
ext("i16x8_extend_high_i8x16_s", 9), // 11
ext("i16x8_extend_high_i8x16_s", 10), // 12
dot(11, 12), // 13
add(8, 13), // 14
ext("i16x8_extend_low_i8x16_s", 9), // 15
ext("i16x8_extend_low_i8x16_s", 10), // 16
dot(15, 16), // 17
add(14, 17), // 18
},
Roots: []int{18},
}
}
func TestA64SdotRewriteChain(t *testing.T) {
tree := fuseDot8ChainTree()
rt := a64Dot8Rewrite(tree, false, false)
if rt == tree {
t.Fatal("eligible tree not rewritten")
}
// Pair (low0, high0) lands as the fresh dot on the first add, pair
// (high1, low1) accumulates on the chain tail; everything between
// is elided.
if got := rt.Nodes[8].Op; got != a64OpSdot16 {
t.Errorf("node 8: got %q, want %q", got, a64OpSdot16)
}
if args := rt.Nodes[8].Args; len(args) != 2 || args[0].Index != 0 || args[1].Index != 1 {
t.Errorf("node 8 args: %+v, want the first byte loads", rt.Nodes[8].Args)
}
if got := rt.Nodes[18].Op; got != a64OpSdotAcc {
t.Errorf("node 18: got %q, want %q", got, a64OpSdotAcc)
}
if args := rt.Nodes[18].Args; len(args) != 3 || args[0].Index != 8 ||
args[1].Index != 9 || args[2].Index != 10 {
t.Errorf("node 18 args: %+v, want acc 8 and the second byte loads", rt.Nodes[18].Args)
}
for _, n := range []int{2, 3, 4, 5, 6, 7, 11, 12, 13, 14, 15, 16, 17} {
if got := rt.Nodes[n].Op; got != a64OpElided {
t.Errorf("node %d: got %q, want elided", n, got)
}
}
}
func TestA64SpliceFusedDot8(t *testing.T) {
// The portable twin keeps the smull/sadalp form (no SDOT upgrade).
var b strings.Builder
spliced, needsTrap, err := a64SpliceFused(&b, fuseDot8Tree(false), nil, fuseTestOffs, true)
if err != nil || !spliced || !needsTrap {
t.Fatalf("spliced=%v trap=%v err=%v", spliced, needsTrap, err)
}
body := b.String()
for _, want := range []string{"// smull v", "// smull2 v", "// saddlp v", "// sadalp v"} {
if !strings.Contains(body, want) {
t.Errorf("missing %q in body:\n%s", want, body)
}
}
if strings.Contains(body, "sshll") {
t.Errorf("extend survived the 8-bit dot selection:\n%s", body)
}
}
func TestA64SpliceFusedSdot(t *testing.T) {
var b strings.Builder
spliced, needsTrap, err := a64SpliceFused(&b, fuseDot8ChainTree(), nil, fuseTestOffs, false)
if err != nil || !spliced || !needsTrap {
t.Fatalf("spliced=%v trap=%v err=%v", spliced, needsTrap, err)
}
body := b.String()
// The permutation constant, its two TBLs per dot, the zeroed
// accumulator and both SDOTs must all be present; no smull-form
// instruction may survive.
for _, want := range []string{
"MOVD $0x0b0a030209080100, R22",
"MOVD $0x0f0e07060d0c0504, R22",
"// tbl v", "// movi v", "// sdot v",
} {
if !strings.Contains(body, want) {
t.Errorf("missing %q in body:\n%s", want, body)
}
}
if got := strings.Count(body, "// sdot v"); got != 2 {
t.Errorf("want 2 sdot, got %d:\n%s", got, body)
}
if got := strings.Count(body, "// movi v"); got != 1 {
t.Errorf("want 1 movi, got %d:\n%s", got, body)
}
if got := strings.Count(body, "// tbl v"); got != 4 {
t.Errorf("want 4 tbl, got %d:\n%s", got, body)
}
for _, bad := range []string{"smull", "saddlp", "sadalp", "sshll"} {
if strings.Contains(body, bad) {
t.Errorf("%s survived the SDOT selection:\n%s", bad, body)
}
}
}
func TestA64SpliceFusedDot8RootExtend(t *testing.T) {
var b strings.Builder
spliced, _, err := a64SpliceFused(&b, fuseDot8Tree(true), nil, fuseTestOffs, false)
if err != nil || !spliced {
t.Fatalf("spliced=%v err=%v", spliced, err)
}
if body := b.String(); !strings.Contains(body, "sshll") {
t.Errorf("literal lowering expected when an extend is a root:\n%s", body)
}
}
// Fast-math mode: SDOT feeds on raw byte sources (no TBL) and the
// mul-by-lane + add pair fuses into FMLA.
func TestA64SpliceFusedFastMath(t *testing.T) {
var b strings.Builder
spliced, _, err := a64SpliceFused(&b, fuseDot8ChainTree(), nil, fastTestOffs, false)
if err != nil || !spliced {
t.Fatalf("spliced=%v err=%v", spliced, err)
}
body := b.String()
if strings.Contains(body, "// tbl v") {
t.Errorf("TBL emitted in fast mode:\n%s", body)
}
if got := strings.Count(body, "// sdot v"); got != 2 {
t.Errorf("want 2 sdot, got %d:\n%s", got, body)
}
}
func TestA64FmlaRewriteFast(t *testing.T) {
// mul_lane feeding an add: splat(f) * v + acc
tree := &simdfuse.Tree{
Name: "simd_p_fxfma",
NumFloats: 1,
NumPairs: 2,
Nodes: []simdfuse.Node{
{Op: "f32x4_splat", Args: []simdfuse.Arg{{Kind: simdfuse.ArgFloat, Index: 0}}},
{Op: "f32x4_mul", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgNode, Index: 0},
{Kind: simdfuse.ArgPairIn, Index: 0}}},
{Op: "f32x4_add", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgPairIn, Index: 1},
{Kind: simdfuse.ArgNode, Index: 1}}},
},
Roots: []int{2},
}
var b strings.Builder
spliced, _, err := a64SpliceFused(&b, tree, nil, fastTestOffs, false)
if err != nil || !spliced {
t.Fatalf("spliced=%v err=%v", spliced, err)
}
// The fast accumulate is SCOPED to dot-kernel trees; a tree with
// no 8-bit dot keeps its IEEE mul + add.
body := b.String()
if strings.Contains(body, "// fmla v") {
t.Errorf("fmla leaked outside dot trees:\n%s", body)
}
}
// A dot tree with the scale tail: the mul-by-lane + add pair fuses
// into FMLA under fast math.
func TestA64FmlaRewriteDotTree(t *testing.T) {
base := fuseDot8ChainTree()
n := len(base.Nodes)
base.NumFloats = 1
base.NumPairs = 1
base.Nodes = append(base.Nodes,
simdfuse.Node{Op: "f32x4_convert_i32x4_s", Args: []simdfuse.Arg{{Kind: simdfuse.ArgNode, Index: n - 1}}}, // n
simdfuse.Node{Op: "f32x4_splat", Args: []simdfuse.Arg{{Kind: simdfuse.ArgFloat, Index: 0}}}, // n+1
simdfuse.Node{Op: "f32x4_mul", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgNode, Index: n}, {Kind: simdfuse.ArgNode, Index: n + 1}}}, // n+2
simdfuse.Node{Op: "f32x4_add", Args: []simdfuse.Arg{
{Kind: simdfuse.ArgPairIn, Index: 0}, {Kind: simdfuse.ArgNode, Index: n + 2}}}, // n+3
)
base.Roots = []int{n + 3}
var b strings.Builder
spliced, _, err := a64SpliceFused(&b, base, nil, fastTestOffs, false)
if err != nil || !spliced {
t.Fatalf("spliced=%v err=%v", spliced, err)
}
body := b.String()
if !strings.Contains(body, "// fmla v") {
t.Errorf("no fmla in fast dot tree:\n%s", body)
}
if strings.Contains(body, "// fadd v") {
t.Errorf("unfused fadd survived:\n%s", body)
}
}