runtime, crypto/x509: fix vet complaints for all windows

Working toward making the tree vet-safe instead of having
so many exceptions in cmd/vet/all/whitelist.

This CL makes "go vet -unsafeptr=false runtime" happy for windows/*,
while keeping "GO_BUILDER_NAME=misc-vetall go tool dist test" happy too.

For #31916.

Change-Id: If37ab2b3f6fca4696b8a6afb2ef11ba6c4fb42e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/176106Reviewed-by: Austin Clements <austin@google.com>

src/cmd/vet/all/whitelist/windows.txt

-// windows-specific vet whitelist. See readme.txt for details.
-
-// Issue 18609
-crypto/x509/root_windows.go: unreachable code
-
-runtime/sys_windows_ARCHSUFF.s: [GOARCH] onosstack: unknown variable usec; offset 0 is fn+0(FP)

src/cmd/vet/all/whitelist/windows_386.txt

-// windows/386-specific vet whitelist. See readme.txt for details.
-
-runtime/sys_windows_386.s: [386] profileloop: use of 4(SP) points beyond argument frame
-runtime/sys_windows_386.s: [386] ctrlhandler: 4(SP) should be _type+0(FP)
-runtime/sys_windows_386.s: [386] callbackasm1+0: function callbackasm1+0 missing Go declaration
-runtime/sys_windows_386.s: [386] tstart: function tstart missing Go declaration
-runtime/sys_windows_386.s: [386] tstart_stdcall: RET without writing to 4-byte ret+4(FP)
-runtime/sys_windows_386.s: [386] sigtramp: function sigtramp missing Go declaration

src/cmd/vet/all/whitelist/windows_amd64.txt

-// windows/amd64-specific vet whitelist. See readme.txt for details.
-
-runtime/sys_windows_amd64.s: [amd64] ctrlhandler: RET without writing to 4-byte ret+8(FP)
-runtime/sys_windows_amd64.s: [amd64] callbackasm1: function callbackasm1 missing Go declaration
-runtime/sys_windows_amd64.s: [amd64] tstart_stdcall: RET without writing to 4-byte ret+8(FP)

src/crypto/x509/root_windows.go

@@ -229,7 +229,11 @@ func loadSystemRoots() (*CertPool, error) {
 	// TODO: restore this functionality on Windows. We tried to do
 	// it in Go 1.8 but had to revert it. See Issue 18609.
 	// Returning (nil, nil) was the old behavior, prior to CL 30578.
+	// The if statement here avoids vet complaining about
+	// unreachable code below.
+	if true {
 		return nil, nil
+	}
 
 	const CRYPT_E_NOT_FOUND = 0x80092004
 

src/runtime/os_windows.go

@@ -133,9 +133,9 @@ var (
 
 // Function to be called by windows CreateThread
 // to start new os thread.
-func tstart_stdcall(newm *m) uint32
+func tstart_stdcall(newm *m)
 
-func ctrlhandler(_type uint32) uint32
+func ctrlhandler(_type uint32)
 
 type mOS struct {
 	waitsema uintptr // semaphore for parking on locks
@@ -907,6 +907,9 @@ func ctrlhandler1(_type uint32) uint32 {
 // in sys_windows_386.s and sys_windows_amd64.s
 func profileloop()
 
+// called from zcallback_windows_*.s to sys_windows_*.s
+func callbackasm1()
+
 var profiletimer uintptr
 
 func profilem(mp *m, thread uintptr) {

src/runtime/sys_windows_386.s

@@ -76,7 +76,7 @@ TEXT runtime·setlasterror(SB),NOSPLIT,$0
 // exception record and context pointers.
 // Handler function is stored in AX.
 // Return 0 for 'not handled', -1 for handled.
-TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
+TEXT sigtramp<>(SB),NOSPLIT,$0-0
 	MOVL	ptrs+0(FP), CX
 	SUBL	$40, SP
 
@@ -155,7 +155,7 @@ done:
 
 TEXT runtime·exceptiontramp(SB),NOSPLIT,$0
 	MOVL	$runtime·exceptionhandler(SB), AX
-	JMP	runtime·sigtramp(SB)
+	JMP	sigtramp<>(SB)
 
 TEXT runtime·firstcontinuetramp(SB),NOSPLIT,$0-0
 	// is never called
@@ -163,17 +163,21 @@ TEXT runtime·firstcontinuetramp(SB),NOSPLIT,$0-0
 
 TEXT runtime·lastcontinuetramp(SB),NOSPLIT,$0-0
 	MOVL	$runtime·lastcontinuehandler(SB), AX
-	JMP	runtime·sigtramp(SB)
+	JMP	sigtramp<>(SB)
 
+// Called by OS using stdcall ABI: bool ctrlhandler(uint32).
 TEXT runtime·ctrlhandler(SB),NOSPLIT,$0
 	PUSHL	$runtime·ctrlhandler1(SB)
+	NOP	SP	// tell vet SP changed - stop checking offsets
 	CALL	runtime·externalthreadhandler(SB)
 	MOVL	4(SP), CX
 	ADDL	$12, SP
 	JMP	CX
 
+// Called by OS using stdcall ABI: uint32 profileloop(void*).
 TEXT runtime·profileloop(SB),NOSPLIT,$0
 	PUSHL	$runtime·profileloop1(SB)
+	NOP	SP	// tell vet SP changed - stop checking offsets
 	CALL	runtime·externalthreadhandler(SB)
 	MOVL	4(SP), CX
 	ADDL	$12, SP
@@ -232,7 +236,7 @@ TEXT runtime·externalthreadhandler(SB),NOSPLIT,$0
 
 GLOBL runtime·cbctxts(SB), NOPTR, $4
 
-TEXT runtime·callbackasm1+0(SB),NOSPLIT,$0
+TEXT runtime·callbackasm1(SB),NOSPLIT,$0
   	MOVL	0(SP), AX	// will use to find our callback context
 
 	// remove return address from stack, we are not returning there
@@ -308,7 +312,7 @@ TEXT runtime·callbackasm1+0(SB),NOSPLIT,$0
 	RET
 
 // void tstart(M *newm);
-TEXT runtime·tstart(SB),NOSPLIT,$0
+TEXT tstart<>(SB),NOSPLIT,$0
 	MOVL	newm+0(FP), CX		// m
 	MOVL	m_g0(CX), DX		// g
 
@@ -340,7 +344,7 @@ TEXT runtime·tstart_stdcall(SB),NOSPLIT,$0
 	MOVL	newm+0(FP), BX
 
 	PUSHL	BX
-	CALL	runtime·tstart(SB)
+	CALL	tstart<>(SB)
 	POPL	BX
 
 	// Adjust stack for stdcall to return properly.
@@ -383,7 +387,7 @@ TEXT runtime·onosstack(SB),NOSPLIT,$0
 	MOVL	SI, m_libcallg(BP)
 	// sp must be the last, because once async cpu profiler finds
 	// all three values to be non-zero, it will use them
-	LEAL	usec+0(FP), SI
+	LEAL	fn+0(FP), SI
 	MOVL	SI, m_libcallsp(BP)
 
 	MOVL	m_g0(BP), SI

src/runtime/sys_windows_amd64.s

@@ -110,7 +110,7 @@ TEXT runtime·setlasterror(SB),NOSPLIT,$0
 // exception record and context pointers.
 // Handler function is stored in AX.
 // Return 0 for 'not handled', -1 for handled.
-TEXT runtime·sigtramp(SB),NOSPLIT|NOFRAME,$0-0
+TEXT sigtramp<>(SB),NOSPLIT|NOFRAME,$0-0
 	// CX: PEXCEPTION_POINTERS ExceptionInfo
 
 	// DI SI BP BX R12 R13 R14 R15 registers and DF flag are preserved
@@ -200,18 +200,18 @@ done:
 
 TEXT runtime·exceptiontramp(SB),NOSPLIT|NOFRAME,$0
 	MOVQ	$runtime·exceptionhandler(SB), AX
-	JMP	runtime·sigtramp(SB)
+	JMP	sigtramp<>(SB)
 
 TEXT runtime·firstcontinuetramp(SB),NOSPLIT|NOFRAME,$0-0
 	MOVQ	$runtime·firstcontinuehandler(SB), AX
-	JMP	runtime·sigtramp(SB)
+	JMP	sigtramp<>(SB)
 
 TEXT runtime·lastcontinuetramp(SB),NOSPLIT|NOFRAME,$0-0
 	MOVQ	$runtime·lastcontinuehandler(SB), AX
-	JMP	runtime·sigtramp(SB)
+	JMP	sigtramp<>(SB)
 
 TEXT runtime·ctrlhandler(SB),NOSPLIT|NOFRAME,$8
-	MOVQ	CX, 16(SP)		// spill
+	MOVQ	CX, _type+16(SP)		// spill
 	MOVQ	$runtime·ctrlhandler1(SB), CX
 	MOVQ	CX, 0(SP)
 	CALL	runtime·externalthreadhandler(SB)
@@ -413,7 +413,7 @@ TEXT runtime·onosstack(SB),NOSPLIT,$0
 	MOVQ	R12, m_libcallg(R13)
 	// sp must be the last, because once async cpu profiler finds
 	// all three values to be non-zero, it will use them
-	LEAQ	usec+0(FP), R12
+	LEAQ	fn+0(FP), R12
 	MOVQ	R12, m_libcallsp(R13)
 
 	MOVQ	m_g0(R13), R14

src/runtime/sys_windows_arm.s

@@ -116,7 +116,7 @@ TEXT runtime·setlasterror(SB),NOSPLIT|NOFRAME,$0
 // int32_t sigtramp(
 //     PEXCEPTION_POINTERS ExceptionInfo,
 //     func *GoExceptionHandler);
-TEXT runtime·sigtramp(SB),NOSPLIT|NOFRAME,$0
+TEXT sigtramp<>(SB),NOSPLIT|NOFRAME,$0
 	MOVM.DB.W [R0, R4-R11, R14], (R13)	// push {r0, r4-r11, lr} (SP-=40)
 	SUB	$(8+20), R13		// reserve space for g, sp, and
 					// parameters/retval to go call
@@ -198,7 +198,7 @@ done:
 	// handler, don't clobber the stored SP and PC on the stack.
 	MOVW	4(R3), R3			// PEXCEPTION_POINTERS->Context
 	MOVW	0x40(R3), R2			// load PC from context record
-	MOVW	$runtime·returntramp(SB), R1
+	MOVW	$returntramp<>(SB), R1
 	CMP	R1, R2
 	B.EQ	return				// do not clobber saved SP/PC
 
@@ -211,7 +211,7 @@ done:
 	// Set up context record to return to returntramp on g0 stack
 	MOVW	R12, 0x38(R3)			// save g0 stack pointer
 						// in context record
-	MOVW	$runtime·returntramp(SB), R2	// save resume address
+	MOVW	$returntramp<>(SB), R2	// save resume address
 	MOVW	R2, 0x40(R3)			// in context record
 
 return:
@@ -222,20 +222,20 @@ return:
 // This is part of the control flow guard workaround.
 // It switches stacks and jumps to the continuation address.
 //
-TEXT runtime·returntramp(SB),NOSPLIT|NOFRAME,$0
+TEXT returntramp<>(SB),NOSPLIT|NOFRAME,$0
 	MOVM.IA	(R13), [R13, R15]		// ldm sp, [sp, pc]
 
 TEXT runtime·exceptiontramp(SB),NOSPLIT|NOFRAME,$0
 	MOVW	$runtime·exceptionhandler(SB), R1
-	B	runtime·sigtramp(SB)
+	B	sigtramp<>(SB)
 
 TEXT runtime·firstcontinuetramp(SB),NOSPLIT|NOFRAME,$0
 	MOVW	$runtime·firstcontinuehandler(SB), R1
-	B	runtime·sigtramp(SB)
+	B	sigtramp<>(SB)
 
 TEXT runtime·lastcontinuetramp(SB),NOSPLIT|NOFRAME,$0
 	MOVW	$runtime·lastcontinuehandler(SB), R1
-	B	runtime·sigtramp(SB)
+	B	sigtramp<>(SB)
 
 TEXT runtime·ctrlhandler(SB),NOSPLIT|NOFRAME,$0
 	MOVW	$runtime·ctrlhandler1(SB), R1
@@ -363,7 +363,7 @@ TEXT runtime·tstart_stdcall(SB),NOSPLIT|NOFRAME,$0
 	BL	runtime·save_g(SB)
 
 	// do per-thread TLS initialization
-	BL	runtime·init_thread_tls(SB)
+	BL	init_thread_tls<>(SB)
 
 	// Layout new m scheduler stack on os stack.
 	MOVW	R13, R0
@@ -654,7 +654,7 @@ TEXT runtime·_initcgo(SB),NOSPLIT|NOFRAME,$0
 	MOVW 	$runtime·tls_g(SB), R1
 	MOVW	R0, (R1)
 
-	BL	runtime·init_thread_tls(SB)
+	BL	init_thread_tls<>(SB)
 
 	MOVW	R4, R13
 	MOVM.IA.W (R13), [R4, R15]	// pop {r4, pc}
@@ -674,7 +674,7 @@ TEXT runtime·_initcgo(SB),NOSPLIT|NOFRAME,$0
 // handler can get the real g from the thread's m.
 //
 // Clobbers R0-R3
-TEXT runtime·init_thread_tls(SB),NOSPLIT|NOFRAME,$0
+TEXT init_thread_tls<>(SB),NOSPLIT|NOFRAME,$0
 	// compute &_TEB->TlsSlots[tls_g]
 	MRC	15, 0, R0, C13, C0, 2
 	ADD	$0xe10, R0