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feat: add fixed-arity Syscall0–Syscall15 variants to avoid heap allocation #445

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feat: add fixed-arity Syscall0–Syscall15 variants to avoid heap allocation #445

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111 changes: 111 additions & 0 deletions func_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -469,6 +469,117 @@ func TestABI_ArgumentPassing(t *testing.T) {
}
})

t.Run("syscall_fixed", func(t *testing.T) {
fn0, err := load.OpenSymbol(lib, "stack_0_uintptr")
if err != nil {
t.Fatalf("OpenSymbol(stack_0_uintptr) failed: %v", err)
}
fn15, err := load.OpenSymbol(lib, "stack_15_uintptr")
if err != nil {
t.Fatalf("OpenSymbol(stack_15_uintptr) failed: %v", err)
}

// stack_0_uintptr takes no arguments and returns the constant 42.
{
got, _, _ := purego.Syscall0(fn0)
gotN, _, _ := purego.SyscallN(fn0)
if got != 42 {
t.Errorf("Syscall0: got %d, want 42", got)
}
if got != gotN {
t.Errorf("Syscall0 vs SyscallN: %d != %d", got, gotN)
}
}

// stack_15_uintptr sums its 15 arguments. Calling it with K explicit
// arguments (the remaining slots are zero-initialised) yields sum(1..K).
check := func(name string, got, gotN uintptr, want int) {
t.Helper()
if got != uintptr(want) {
t.Errorf("%s: got %d, want %d", name, got, want)
}
if got != gotN {
t.Errorf("%s vs SyscallN: %d != %d", name, got, gotN)
}
}

{
got, _, _ := purego.Syscall1(fn15, 1)
gotN, _, _ := purego.SyscallN(fn15, 1)
check("Syscall1", got, gotN, 1)
}
{
got, _, _ := purego.Syscall2(fn15, 1, 2)
gotN, _, _ := purego.SyscallN(fn15, 1, 2)
check("Syscall2", got, gotN, 3)
}
{
got, _, _ := purego.Syscall3(fn15, 1, 2, 3)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3)
check("Syscall3", got, gotN, 6)
}
{
got, _, _ := purego.Syscall4(fn15, 1, 2, 3, 4)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4)
check("Syscall4", got, gotN, 10)
}
{
got, _, _ := purego.Syscall5(fn15, 1, 2, 3, 4, 5)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5)
check("Syscall5", got, gotN, 15)
}
{
got, _, _ := purego.Syscall6(fn15, 1, 2, 3, 4, 5, 6)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6)
check("Syscall6", got, gotN, 21)
}
{
got, _, _ := purego.Syscall7(fn15, 1, 2, 3, 4, 5, 6, 7)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7)
check("Syscall7", got, gotN, 28)
}
{
got, _, _ := purego.Syscall8(fn15, 1, 2, 3, 4, 5, 6, 7, 8)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8)
check("Syscall8", got, gotN, 36)
}
{
got, _, _ := purego.Syscall9(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9)
check("Syscall9", got, gotN, 45)
}
{
got, _, _ := purego.Syscall10(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
check("Syscall10", got, gotN, 55)
}
{
got, _, _ := purego.Syscall11(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
check("Syscall11", got, gotN, 66)
}
{
got, _, _ := purego.Syscall12(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
check("Syscall12", got, gotN, 78)
}
{
got, _, _ := purego.Syscall13(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
check("Syscall13", got, gotN, 91)
}
{
got, _, _ := purego.Syscall14(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
check("Syscall14", got, gotN, 105)
}
{
got, _, _ := purego.Syscall15(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
gotN, _, _ := purego.SyscallN(fn15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
check("Syscall15", got, gotN, 120)
}
})

t.Run("32_mixed_int_float", func(t *testing.T) {
if unsafe.Sizeof(uintptr(0)) == 4 {
t.Skip("requires 64-bit uintptr slots")
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