runtime: remove unused badsignal2 on windows

This CL removes badsignal2 function, as it is unused on Windows.

badsignal2 was originally intended to abort the process when
an exception was raised on a non-Go thread, following the same approach
as Linux and others.

Since it was added, back on https://golang.org/cl/5797068, it has caused
several issues on Windows, see #8224 and #50877. That's because we can't
know wether the signal is bad or not, as our trap might not be at the
end of the exception handler chain.

To fix those issues, https://golang.org/cl/104200046 and CL 442896
stopped calling badsignal2, and CL 458135 removed one last incorrect
call on amd64 and 386.

Change-Id: I5bd31ee2672118ae0f1a2c8b46a1bb0f4893a011
Reviewed-on: https://go-review.googlesource.com/c/go/+/463116
Reviewed-by: Bryan Mills <[email protected]>
Run-TryBot: Quim Muntal <[email protected]>
Reviewed-by: Alex Brainman <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: qmuntal

src/runtime/os_windows.go

@@ -546,8 +546,6 @@ func initLongPathSupport() {
 func osinit() {
 	asmstdcallAddr = unsafe.Pointer(abi.FuncPCABI0(asmstdcall))
 
-	setBadSignalMsg()
-
 	loadOptionalSyscalls()
 
 	disableWER()

src/runtime/signal_windows.go

@@ -375,19 +375,6 @@ func sigpanic() {
 	throw("fault")
 }
 
-var (
-	badsignalmsg [100]byte
-	badsignallen int32
-)
-
-func setBadSignalMsg() {
-	const msg = "runtime: signal received on thread not created by Go.\n"
-	for i, c := range msg {
-		badsignalmsg[i] = byte(c)
-		badsignallen++
-	}
-}
-
 // Following are not implemented.
 
 func initsig(preinit bool) {
@@ -402,12 +389,6 @@ func sigdisable(sig uint32) {
 func sigignore(sig uint32) {
 }
 
-func badsignal2()
-
-func raisebadsignal(sig uint32) {
-	badsignal2()
-}
-
 func signame(sig uint32) string {
 	return ""
 }

src/runtime/sys_windows_386.s

@@ -44,28 +44,6 @@ TEXT runtime·asmstdcall(SB),NOSPLIT,$0
 
 	RET
 
-TEXT	runtime·badsignal2(SB),NOSPLIT,$24
-	// stderr
-	MOVL	$-12, 0(SP)
-	MOVL	SP, BP
-	CALL	*runtime·_GetStdHandle(SB)
-	MOVL	BP, SP
-
-	MOVL	AX, 0(SP)	// handle
-	MOVL	$runtime·badsignalmsg(SB), DX // pointer
-	MOVL	DX, 4(SP)
-	MOVL	runtime·badsignallen(SB), DX // count
-	MOVL	DX, 8(SP)
-	LEAL	20(SP), DX  // written count
-	MOVL	$0, 0(DX)
-	MOVL	DX, 12(SP)
-	MOVL	$0, 16(SP) // overlapped
-	CALL	*runtime·_WriteFile(SB)
-
-	// Does not return.
-	CALL	runtime·abort(SB)
-	RET
-
 // faster get/set last error
 TEXT runtime·getlasterror(SB),NOSPLIT,$0
 	MOVL	0x34(FS), AX

src/runtime/sys_windows_amd64.s

@@ -75,30 +75,6 @@ loadregs:
 
 	RET
 
-TEXT runtime·badsignal2(SB),NOSPLIT|NOFRAME,$48
-	// stderr
-	MOVQ	$-12, CX // stderr
-	MOVQ	CX, 0(SP)
-	MOVQ	runtime·_GetStdHandle(SB), AX
-	CALL	AX
-
-	MOVQ	AX, CX	// handle
-	MOVQ	CX, 0(SP)
-	MOVQ	$runtime·badsignalmsg(SB), DX // pointer
-	MOVQ	DX, 8(SP)
-	MOVL	$runtime·badsignallen(SB), R8 // count
-	MOVQ	R8, 16(SP)
-	LEAQ	40(SP), R9  // written count
-	MOVQ	$0, 0(R9)
-	MOVQ	R9, 24(SP)
-	MOVQ	$0, 32(SP)	// overlapped
-	MOVQ	runtime·_WriteFile(SB), AX
-	CALL	AX
-
-	// Does not return.
-	CALL	runtime·abort(SB)
-	RET
-
 // faster get/set last error
 TEXT runtime·getlasterror(SB),NOSPLIT,$0
 	MOVQ	0x30(GS), AX

src/runtime/sys_windows_arm.s

@@ -76,30 +76,6 @@ loadregs:
 
 	MOVM.IA.W (R13), [R4, R5, R15]
 
-TEXT runtime·badsignal2(SB),NOSPLIT|NOFRAME,$0
-	MOVM.DB.W [R4, R14], (R13)	// push {r4, lr}
-	MOVW	R13, R4			// save original stack pointer
-	SUB	$8, R13			// space for 2 variables
-	BIC	$0x7, R13		// alignment for ABI
-
-	// stderr
-	MOVW	runtime·_GetStdHandle(SB), R1
-	MOVW	$-12, R0
-	BL	(R1)
-
-	MOVW	$runtime·badsignalmsg(SB), R1	// lpBuffer
-	MOVW	$runtime·badsignallen(SB), R2	// lpNumberOfBytesToWrite
-	MOVW	(R2), R2
-	ADD	$0x4, R13, R3		// lpNumberOfBytesWritten
-	MOVW	$0, R12			// lpOverlapped
-	MOVW	R12, (R13)
-
-	MOVW	runtime·_WriteFile(SB), R12
-	BL	(R12)
-
-	// Does not return.
-	B	runtime·abort(SB)
-
 TEXT runtime·getlasterror(SB),NOSPLIT,$0
 	MRC	15, 0, R0, C13, C0, 2
 	MOVW	0x34(R0), R0

src/runtime/sys_windows_arm64.s

@@ -99,32 +99,6 @@ _0args:
 	LDP.P	32(RSP), (R29, R30)
 	RET
 
-TEXT runtime·badsignal2(SB),NOSPLIT,$16-0
-	NO_LOCAL_POINTERS
-
-	// stderr
-	MOVD	runtime·_GetStdHandle(SB), R1
-	MOVD	$-12, R0
-	SUB	$16, RSP	// skip over saved frame pointer below RSP
-	BL	(R1)
-	ADD	$16, RSP
-
-	// handle in R0 already
-	MOVD	$runtime·badsignalmsg(SB), R1	// lpBuffer
-	MOVD	$runtime·badsignallen(SB), R2	// lpNumberOfBytesToWrite
-	MOVD	(R2), R2
-	// point R3 to stack local that will receive number of bytes written
-	ADD	$16, RSP, R3		// lpNumberOfBytesWritten
-	MOVD	$0, R4			// lpOverlapped
-	MOVD	runtime·_WriteFile(SB), R12
-	SUB	$16, RSP	// skip over saved frame pointer below RSP
-	BL	(R12)
-
-	// Does not return.
-	B	runtime·abort(SB)
-
-	RET
-
 TEXT runtime·getlasterror(SB),NOSPLIT|NOFRAME,$0
 	MOVD	TEB_error(R18_PLATFORM), R0
 	MOVD	R0, ret+0(FP)