BTW in your test file, you can directly append your bytes slice. b1 = append(b1, vs...) and slicesEqual is redundant, bytes.Equal does test the length of two arguments.
On Tuesday, September 20, 2016 at 6:56:55 AM UTC+8, Caleb Spare wrote: > > I'm trying to call a Go function from asm and I'm having trouble figuring > out the details. > > (In the past I've always endeavored to avoid this situation and make all > my asm functions be leaf functions, but in my current use case it would be > most helpful to be able to call a Go helper.) > > See the demo code at > https://github.com/cespare/misc/tree/master/asm/stackmap or go get > github.com/cespare/misc/asm/stackmap. > > For > the > demo, I have a small function with an append-style API: > > func X(b []byte) []byte > > This calls a Go helper growSlice. > > This code sometimes works, but if I run `go test -count 1000` I'll quickly > see > > runtime: frame github.com/cespare/misc/asm/stackmap.X untyped locals > 0xc420042bf8+0x30 > fatal error: missing stackmap > ... > > I've read through the Runtime Coordination section of the > asm > walkthrough (https://golang.org/doc/asm#runtime) several times, but I > don't see the problem. > > Here is my understanding of a few relevant bits of that section (which > might be incorrect): > > If the results will hold live pointers during a call instruction, the >> function should start by zeroing the results and then executing the >> pseudo-instruction GO_RESULTS_INITIALIZED. > > > This doesn't seem to apply to my code because the results aren't populated > until after the CALL. > > If a function has no local stack frame, the pointer information can be >> omitted. This is indicated by a local frame size annotation of $0-n on the >> TEXT instruction. The pointer information can also be omitted if the >> function contains no call instructions. Otherwise, the local stack frame >> must not contain pointers, and the assembly must confirm this fact by >> executing the pseudo-instruction NO_LOCAL_POINTERS. > > > My function makes a CALL with arguments. But it has to have a pointer > (the slice) on the local stack frame in order to pass to that helper. I > don't really understand what this section means. > > `go vet` doesn't say anything about my code. > > Any ideas? > > Thanks! > Caleb > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
