runtime, reflect: use correctly aligned stack frame sizes on arm64

arm64 requires either no stack frame or a frame with a size that is 8 mod 16
(adding the saved LR will make it 16-aligned).

The cmd/internal/obj/arm64 has been silently aligning frames, but it led to
a terrible bug when the compiler and obj disagreed on the frame size,
and it's just generally confusing, so we're going to make misaligned frames
an error instead of something that is silently changed.

This CL prepares by updating assembly files.
Note that the changes in this CL are already being done silently by
cmd/internal/obj/arm64, so there is no semantic effect here,
just a clarity effect.

For #9880.

Change-Id: Ibd6928dc5fdcd896c2bacd0291bf26b364591e28
Reviewed-on: https://go-review.googlesource.com/12845
Reviewed-by: Austin Clements <[email protected]>

Author: rsc

src/reflect/asm_arm64.s

@@ -9,7 +9,7 @@
 // See the comment on the declaration of makeFuncStub in makefunc.go
 // for more details.
 // No arg size here, runtime pulls arg map out of the func value.
-TEXT ·makeFuncStub(SB),(NOSPLIT|WRAPPER),$16
+TEXT ·makeFuncStub(SB),(NOSPLIT|WRAPPER),$24
 	NO_LOCAL_POINTERS
 	MOVD	R26, 8(RSP)
 	MOVD	$argframe+0(FP), R3
@@ -21,7 +21,7 @@ TEXT ·makeFuncStub(SB),(NOSPLIT|WRAPPER),$16
 // See the comment on the declaration of methodValueCall in makefunc.go
 // for more details.
 // No arg size here; runtime pulls arg map out of the func value.
-TEXT ·methodValueCall(SB),(NOSPLIT|WRAPPER),$16
+TEXT ·methodValueCall(SB),(NOSPLIT|WRAPPER),$24
 	NO_LOCAL_POINTERS
 	MOVD	R26, 8(RSP)
 	MOVD	$argframe+0(FP), R3

src/runtime/asm_arm64.s

@@ -424,33 +424,35 @@ end:						\
 	BL	runtime·callwritebarrier(SB);	\
 	RET
 
-CALLFN(·call16, 16)
-CALLFN(·call32, 32)
-CALLFN(·call64, 64)
-CALLFN(·call128, 128)
-CALLFN(·call256, 256)
-CALLFN(·call512, 512)
-CALLFN(·call1024, 1024)
-CALLFN(·call2048, 2048)
-CALLFN(·call4096, 4096)
-CALLFN(·call8192, 8192)
-CALLFN(·call16384, 16384)
-CALLFN(·call32768, 32768)
-CALLFN(·call65536, 65536)
-CALLFN(·call131072, 131072)
-CALLFN(·call262144, 262144)
-CALLFN(·call524288, 524288)
-CALLFN(·call1048576, 1048576)
-CALLFN(·call2097152, 2097152)
-CALLFN(·call4194304, 4194304)
-CALLFN(·call8388608, 8388608)
-CALLFN(·call16777216, 16777216)
-CALLFN(·call33554432, 33554432)
-CALLFN(·call67108864, 67108864)
-CALLFN(·call134217728, 134217728)
-CALLFN(·call268435456, 268435456)
-CALLFN(·call536870912, 536870912)
-CALLFN(·call1073741824, 1073741824)
+// These have 8 added to make the overall frame size a multiple of 16,
+// as required by the ABI. (There is another +8 for the saved LR.)
+CALLFN(·call16, 24 )
+CALLFN(·call32, 40 )
+CALLFN(·call64, 72 )
+CALLFN(·call128, 136 )
+CALLFN(·call256, 264 )
+CALLFN(·call512, 520 )
+CALLFN(·call1024, 1032 )
+CALLFN(·call2048, 2056 )
+CALLFN(·call4096, 4104 )
+CALLFN(·call8192, 8200 )
+CALLFN(·call16384, 16392 )
+CALLFN(·call32768, 32776 )
+CALLFN(·call65536, 65544 )
+CALLFN(·call131072, 131080 )
+CALLFN(·call262144, 262152 )
+CALLFN(·call524288, 524296 )
+CALLFN(·call1048576, 1048584 )
+CALLFN(·call2097152, 2097160 )
+CALLFN(·call4194304, 4194312 )
+CALLFN(·call8388608, 8388616 )
+CALLFN(·call16777216, 16777224 )
+CALLFN(·call33554432, 33554440 )
+CALLFN(·call67108864, 67108872 )
+CALLFN(·call134217728, 134217736 )
+CALLFN(·call268435456, 268435464 )
+CALLFN(·call536870912, 536870920 )
+CALLFN(·call1073741824, 1073741832 )
 
 // bool cas(uint32 *ptr, uint32 old, uint32 new)
 // Atomically:
@@ -613,7 +615,7 @@ TEXT runtime·cgocallback(SB),NOSPLIT,$24-24
 
 // cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize)
 // See cgocall.go for more details.
-TEXT ·cgocallback_gofunc(SB),NOSPLIT,$16-24
+TEXT ·cgocallback_gofunc(SB),NOSPLIT,$24-24
 	NO_LOCAL_POINTERS
 
 	// Load g from thread-local storage.
@@ -721,7 +723,7 @@ droppedm:
 
 // Called from cgo wrappers, this function returns g->m->curg.stack.hi.
 // Must obey the gcc calling convention.
-TEXT _cgo_topofstack(SB),NOSPLIT,$16
+TEXT _cgo_topofstack(SB),NOSPLIT,$24
 	// g (R28) and REGTMP (R27)  might be clobbered by load_g. They
 	// are callee-save in the gcc calling convention, so save them.
 	MOVD	R27, savedR27-8(SP)

src/runtime/sys_linux_arm64.s

@@ -115,7 +115,7 @@ TEXT runtime·getrlimit(SB),NOSPLIT,$-8-20
 	MOVW	R0, ret+16(FP)
 	RET
 
-TEXT runtime·usleep(SB),NOSPLIT,$16-4
+TEXT runtime·usleep(SB),NOSPLIT,$24-4
 	MOVWU	usec+0(FP), R3
 	MOVD	R3, R5
 	MOVW	$1000000, R4
@@ -180,7 +180,7 @@ TEXT runtime·mincore(SB),NOSPLIT,$-8-28
 	RET
 
 // func now() (sec int64, nsec int32)
-TEXT time·now(SB),NOSPLIT,$16-12
+TEXT time·now(SB),NOSPLIT,$24-12
 	MOVD	RSP, R0
 	MOVD	$0, R1
 	MOVD	$SYS_gettimeofday, R8
@@ -193,7 +193,7 @@ TEXT time·now(SB),NOSPLIT,$16-12
 	MOVW	R5, nsec+8(FP)
 	RET
 
-TEXT runtime·nanotime(SB),NOSPLIT,$16-8
+TEXT runtime·nanotime(SB),NOSPLIT,$24-8
 	MOVW	$1, R0 // CLOCK_MONOTONIC
 	MOVD	RSP, R1
 	MOVD	$SYS_clock_gettime, R8