purego: remove go:nosplit at SyscallN (#24)

this is allowed because SyscallN also uses go:uintptrescapes which forces any objects that get passed as uintptr's to be placed on the heap where a stack split won't affect them. See the compile docs for an explanation.

I've tested this change on Oto (amd64 & arm64) without optimizations. I also ran all the test for ebitengine (amd64 & arm64) with OpenGL and Metal.

All this to say, this won't break anything.

This change fixes Oto#182

commit: 58aa9be54b86ebaa662778658ecf943a3d1976ac
author: TotallyGamerJet · 4y ago · 2022-08-23 12:44 UTC
committer: GitHub · 4y ago · 2022-08-23 12:44 UTC
parent: c1f3f96
signature: GPG Unverified4AEE18F83AFDEB23 The key is unknown

1 file · +5 -1

M syscall.go +5 -1


@@ -18,7 +18,11 @@ const maxArgs = 9
18	18		//
19	19		// On amd64, if there are more than 8 floats the 9th and so on will be placed incorrectly on the
20	20		// stack.
21		-	//go:nosplit
	21	+	//
	22	+	// The pragma go:nosplit is not needed at this function declaration because it uses go:uintptrescapes
	23	+	// which forces all the objects that the uintptrs point to onto the heap where a stack split won't affect
	24	+	// their memory location.
	25	+	//
22	26		//go:uintptrescapes
23	27		func SyscallN(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {
24	28		if fn == 0 {


@@ -18,7 +18,11 @@ const maxArgs = 9
18		//	18		//
19		// On amd64, if there are more than 8 floats the 9th and so on will be placed incorrectly on the	19		// On amd64, if there are more than 8 floats the 9th and so on will be placed incorrectly on the
20		// stack.	20		// stack.
21	-	//go:nosplit	21	+	//
			22	+	// The pragma go:nosplit is not needed at this function declaration because it uses go:uintptrescapes
			23	+	// which forces all the objects that the uintptrs point to onto the heap where a stack split won't affect
			24	+	// their memory location.
			25	+	//
22		//go:uintptrescapes	26		//go:uintptrescapes
23		func SyscallN(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {	27		func SyscallN(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {
24		if fn == 0 {	28		if fn == 0 {