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cmd/asm: add error check for move constant instructions on arm64

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The current Go assembler encodes "MOVK $(0<<16|32|48), Rd" as the
same binary with "MOVK $0, Rd", but for arm64 move constant instructions
MOVK, MOVN and MOVZ, "op $0, Rd" and "op $(0<<16|32|48), Rd" have
different semantics. In order not to change the way the assembler
frontend parses constants, this patch adds a check for the zero shifts.

Change-Id: Ia844c419ce49f63605b549e3a2e98d9075dd1cf1
Reviewed-on: https://go-review.googlesource.com/c/go/+/275812
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: fannie zhang <Fannie.Zhang@arm.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
fanzha02 2021-09-28 13:46:14 +08:00 committed by fannie zhang
parent 2d6d558417
commit 6656269288
2 changed files with 5 additions and 0 deletions
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2
src/cmd/asm/internal/asm/testdata/arm64error.s vendored
View file

@ -430,4 +430,6 @@ TEXT errors(SB),$0
STP (R3, R4), 0x1234567(R27) // ERROR "REGTMP used in large offset store"
LDP 0x1234567(R27), (R3, R4) // ERROR "REGTMP used in large offset load"
STP (R26, R27), 700(R2) // ERROR "cannot use REGTMP as source"
MOVK $0, R10 // ERROR "zero shifts cannot be handled correctly"
MOVK $(0<<32), R10 // ERROR "zero shifts cannot be handled correctly"
RET

3
src/cmd/internal/obj/arm64/asm7.go
View file

@ -3877,6 +3877,9 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
o1 = c.opirr(p, p.As)
d := p.From.Offset
if d == 0 {
c.ctxt.Diag("zero shifts cannot be handled correctly: %v", p)
}
s := movcon(d)
if s < 0 || s >= 4 {
c.ctxt.Diag("bad constant for MOVK: %#x\n%v", uint64(d), p)