fix callbacks on go 1.15 (#34)

Go 1.16 significantly changed the way Go calls into C code in  golang/go#30c1887. Purego assumed versioned 1.16 method. This commit expands support back down to 1.15.

Closes #27

commit: 3aa994fcbff60ba81dc1120e4fd38dd6d8546c24
author: TotallyGamerJet · 4y ago · 2022-09-07 02:42 UTC
committer: GitHub · 4y ago · 2022-09-07 02:42 UTC
parent: 46cb710
signature: GPG Unverified4AEE18F83AFDEB23 The key is unknown

5 files · +53 -24

M .github/workflows/test.yml +0 -1


@@ -72,6 +72,5 @@ jobs:
72	72		go build -v .
73	73
74	74		- name: go test
75		-	if: ${{ !startsWith(matrix.go, '1.15.') }} # TODO: Remove this condition after #27 is fixed.
76	75		run: \|
77	76		go test -tags=example ${{ !startsWith(matrix.go, '1.15.') && !startsWith(matrix.go, '1.16.') && '-shuffle=on' \|\| '' }} -v -count=10 ./...


@@ -72,6 +72,5 @@ jobs:
72		go build -v .	72	go build -v .
73			73
74		- name: go test	74	- name: go test
75	-	if: ${{ !startsWith(matrix.go, '1.15.') }} # TODO: Remove this condition after #27 is fixed.
76		run: \|	75	run: \|
77		go test -tags=example ${{ !startsWith(matrix.go, '1.15.') && !startsWith(matrix.go, '1.16.') && '-shuffle=on' \|\| '' }} -v -count=10 ./...	76	go test -tags=example ${{ !startsWith(matrix.go, '1.15.') && !startsWith(matrix.go, '1.16.') && '-shuffle=on' \|\| '' }} -v -count=10 ./...

A callback_go1_15_darwin_amd64.go +16 -0

@@ -0,0 +1,16 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
	3	+
	4	+	//go:build !go1.16
	5	+	// +build !go1.16
	6	+
	7	+	package purego
	8	+
	9	+	// callbackWrapPicker is here because Go 1.16+ needs it
	10	+	// to decide between stack and register arguments.
	11	+	// This only has a single pointer because Go 1.15 runtime.cgocallback
	12	+	// dereferences the argument once before passing it to this
	13	+	// function.
	14	+	func callbackWrapPicker(stack, _ *callbackArgs) {
	15	+	callbackWrap(stack)
	16	+	}

@@ -0,0 +1,16 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
	3	+
	4	+	//go:build !go1.16
	5	+	// +build !go1.16
	6	+
	7	+	package purego
	8	+
	9	+	// callbackWrapPicker is here because Go 1.16+ needs it
	10	+	// to decide between stack and register arguments.
	11	+	// This only has a single pointer because Go 1.15 runtime.cgocallback
	12	+	// dereferences the argument once before passing it to this
	13	+	// function.
	14	+	func callbackWrapPicker(stack, _ *callbackArgs) {
	15	+	callbackWrap(stack)
	16	+	}

A callback_go1_16_darwin_amd64.go +24 -0

@@ -0,0 +1,24 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
	3	+
	4	+	//go:build go1.16
	5	+	// +build go1.16
	6	+
	7	+	package purego
	8	+
	9	+	// callbackWrapPicker gets called with whatever is on the stack and in the first register.
	10	+	// Depending on which version of Go that uses stack or register-based
	11	+	// calling it passes the respective argument to the real calbackWrap function.
	12	+	// The other argument is therefore invalid and points to undefined memory so don't use it.
	13	+	// This function is necessary since we can't use the ABIInternal selector which is only
	14	+	// valid in the runtime.
	15	+	//
	16	+	// the double indirection is because Go 1.15 will do that in runtime.cgocallback
	17	+	// but in 1.16+ it doesn't so we do it here.
	18	+	func callbackWrapPicker(stack, register **callbackArgs) {
	19	+	if stackCallingConvention {
	20	+	callbackWrap(*stack)
	21	+	} else {
	22	+	callbackWrap(*register)
	23	+	}
	24	+	}

@@ -0,0 +1,24 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
	3	+
	4	+	//go:build go1.16
	5	+	// +build go1.16
	6	+
	7	+	package purego
	8	+
	9	+	// callbackWrapPicker gets called with whatever is on the stack and in the first register.
	10	+	// Depending on which version of Go that uses stack or register-based
	11	+	// calling it passes the respective argument to the real calbackWrap function.
	12	+	// The other argument is therefore invalid and points to undefined memory so don't use it.
	13	+	// This function is necessary since we can't use the ABIInternal selector which is only
	14	+	// valid in the runtime.
	15	+	//
	16	+	// the double indirection is because Go 1.15 will do that in runtime.cgocallback
	17	+	// but in 1.16+ it doesn't so we do it here.
	18	+	func callbackWrapPicker(stack, register **callbackArgs) {
	19	+	if stackCallingConvention {
	20	+	callbackWrap(*stack)
	21	+	} else {
	22	+	callbackWrap(*register)
	23	+	}
	24	+	}

M sys_darwin_amd64.s +13 -9


@@ -115,23 +115,27 @@ TEXT callbackasm1(SB), NOSPLIT, $0
115	115
116	116		// Create a struct callbackArgs on our stack to be passed as
117	117		// the "frame" to cgocallback and on to callbackWrap.
118		-	// $24 to make enough room for the arguments to runtime.cgocallback
119		-	SUBQ $(24+callbackArgs__size), SP
120		-	MOVQ AX, (24+callbackArgs_index)(SP) // callback index
121		-	MOVQ R8, (24+callbackArgs_args)(SP) // address of args vector
122		-	MOVQ $0, (24+callbackArgs_result)(SP) // result
123		-	LEAQ 24(SP), AX // take the address of callbackArgs
	118	+	// $32 to make enough room for the arguments to runtime.cgocallback
	119	+	// and on Go 1.15 to take a pointer to the pointer to callbackArgs
	120	+	SUBQ $(32+callbackArgs__size), SP
	121	+	MOVQ AX, (32+callbackArgs_index)(SP) // callback index
	122	+	MOVQ R8, (32+callbackArgs_args)(SP) // address of args vector
	123	+	MOVQ $0, (32+callbackArgs_result)(SP) // result
	124	+	LEAQ 32(SP), AX // take the address of callbackArgs
	125	+
	126	+	MOVQ AX, 24(SP) // get a **callbackArgs for go 1.15
	127	+	LEAQ 24(SP), AX // ^^^^
124	128
125	129		// Call cgocallback, which will call callbackWrap(frame).
126		-	MOVQ $0, 16(SP) // context
	130	+	MOVQ $8, 16(SP) // context is 0 or argsize (including return value) for Go 1.15
127	131		MOVQ AX, 8(SP) // frame (address of callbackArgs)
128	132		MOVQ $callbackWrapInternal<>(SB), BX
129	133		MOVQ BX, 0(SP) // PC of function value to call (callbackWrap)
130	134		CALL runtime·cgocallback(SB) // runtime.cgocallback(fn, frame, ctxt uintptr)
131	135
132	136		// Get callback result.
133		-	MOVQ (24+callbackArgs_result)(SP), AX
134		-	ADDQ $(24+callbackArgs__size), SP // remove callbackArgs struct
	137	+	MOVQ (32+callbackArgs_result)(SP), AX
	138	+	ADDQ $(32+callbackArgs__size), SP // remove callbackArgs struct
135	139
136	140		POP_REGS_HOST_TO_ABI0()
137	141


@@ -115,23 +115,27 @@ TEXT callbackasm1(SB), NOSPLIT, $0
115			115
116		// Create a struct callbackArgs on our stack to be passed as	116		// Create a struct callbackArgs on our stack to be passed as
117		// the "frame" to cgocallback and on to callbackWrap.	117		// the "frame" to cgocallback and on to callbackWrap.
118	-	// $24 to make enough room for the arguments to runtime.cgocallback	118	+	// $32 to make enough room for the arguments to runtime.cgocallback
119	-	SUBQ $(24+callbackArgs__size), SP	119	+	// and on Go 1.15 to take a pointer to the pointer to callbackArgs
120	-	MOVQ AX, (24+callbackArgs_index)(SP) // callback index	120	+	SUBQ $(32+callbackArgs__size), SP
121	-	MOVQ R8, (24+callbackArgs_args)(SP) // address of args vector	121	+	MOVQ AX, (32+callbackArgs_index)(SP) // callback index
122	-	MOVQ $0, (24+callbackArgs_result)(SP) // result	122	+	MOVQ R8, (32+callbackArgs_args)(SP) // address of args vector
123	-	LEAQ 24(SP), AX // take the address of callbackArgs	123	+	MOVQ $0, (32+callbackArgs_result)(SP) // result
			124	+	LEAQ 32(SP), AX // take the address of callbackArgs
			125	+
			126	+	MOVQ AX, 24(SP) // get a **callbackArgs for go 1.15
			127	+	LEAQ 24(SP), AX // ^^^^
124			128
125		// Call cgocallback, which will call callbackWrap(frame).	129		// Call cgocallback, which will call callbackWrap(frame).
126	-	MOVQ $0, 16(SP) // context	130	+	MOVQ $8, 16(SP) // context is 0 or argsize (including return value) for Go 1.15
127		MOVQ AX, 8(SP) // frame (address of callbackArgs)	131		MOVQ AX, 8(SP) // frame (address of callbackArgs)
128		MOVQ $callbackWrapInternal<>(SB), BX	132		MOVQ $callbackWrapInternal<>(SB), BX
129		MOVQ BX, 0(SP) // PC of function value to call (callbackWrap)	133		MOVQ BX, 0(SP) // PC of function value to call (callbackWrap)
130		CALL runtime·cgocallback(SB) // runtime.cgocallback(fn, frame, ctxt uintptr)	134		CALL runtime·cgocallback(SB) // runtime.cgocallback(fn, frame, ctxt uintptr)
131			135
132		// Get callback result.	136		// Get callback result.
133	-	MOVQ (24+callbackArgs_result)(SP), AX	137	+	MOVQ (32+callbackArgs_result)(SP), AX
134	-	ADDQ $(24+callbackArgs__size), SP // remove callbackArgs struct	138	+	ADDQ $(32+callbackArgs__size), SP // remove callbackArgs struct
135			139
136		POP_REGS_HOST_TO_ABI0()	140		POP_REGS_HOST_TO_ABI0()
137			141

M syscall_darwin.go +0 -14


@@ -95,20 +95,6 @@ const callbackMaxFrame = 64 * ptrSize
95	95		// callbackasmABI0 is implemented in zcallback_GOOS_GOARCH.s
96	96		var callbackasmABI0 uintptr
97	97
98		-	// callbackWrapPicker gets whatever is on the stack and in the first register.
99		-	// Depending on which version of Go that uses stack or register-based
100		-	// calling it passes the respective argument to the real calbackWrap function.
101		-	// The other argument is therefore invalid and points to undefined memory so don't use it.
102		-	// This function is necessary since we can't use the ABIInternal selector which is only
103		-	// valid in the runtime.
104		-	func callbackWrapPicker(stack, register *callbackArgs) {
105		-	if stackCallingConvention {
106		-	callbackWrap(stack)
107		-	} else {
108		-	callbackWrap(register)
109		-	}
110		-	}
111		-
112	98		// callbackWrap is called by assembly code which determines which Go function to call.
113	99		// This function takes the arguments and passes them to the Go function and returns the result.
114	100		func callbackWrap(a *callbackArgs) {


@@ -95,20 +95,6 @@ const callbackMaxFrame = 64 * ptrSize
95		// callbackasmABI0 is implemented in zcallback_GOOS_GOARCH.s	95	// callbackasmABI0 is implemented in zcallback_GOOS_GOARCH.s
96		var callbackasmABI0 uintptr	96	var callbackasmABI0 uintptr
97			97
98	-	// callbackWrapPicker gets whatever is on the stack and in the first register.
99	-	// Depending on which version of Go that uses stack or register-based
100	-	// calling it passes the respective argument to the real calbackWrap function.
101	-	// The other argument is therefore invalid and points to undefined memory so don't use it.
102	-	// This function is necessary since we can't use the ABIInternal selector which is only
103	-	// valid in the runtime.
104	-	func callbackWrapPicker(stack, register *callbackArgs) {
105	-	if stackCallingConvention {
106	-	callbackWrap(stack)
107	-	} else {
108	-	callbackWrap(register)
109	-	}
110	-	}
111	-
112		// callbackWrap is called by assembly code which determines which Go function to call.	98	// callbackWrap is called by assembly code which determines which Go function to call.
113		// This function takes the arguments and passes them to the Go function and returns the result.	99	// This function takes the arguments and passes them to the Go function and returns the result.
114		func callbackWrap(a *callbackArgs) {	100	func callbackWrap(a *callbackArgs) {