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cmd/internal/obj/x86: disallow PC/FP/SB scaled index 

Reject to compile I386/AMD64 asm code that contains
(Register)(PseudoReg*scale) forms of memory operands.
Example of such program: "CALL (AX)(PC*2)".
PseudoReg is one of the PC, FP, SB (but not SP).

When pseudo-register is used in register indirect as
scaled index base, x86 backend will panic because
its register file misses SB/FP/PC registers.

Fixes #12657.

Change-Id: I30fca797b537cbc86ab47583ae96c6a0c59acaa1
Reviewed-on: https://go-review.googlesource.com/107835
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
quasilyte 2018-04-18 19:49:27 +03:00 committed by Brad Fitzpatrick
parent dd71e3fef4
commit d487488135
2 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/cmd/asm/internal/asm/testdata/amd64error.s vendored
View File

@ -45,4 +45,8 @@ TEXT errors(SB),$0
ADDQ 433954697820(AX), AX // ERROR "offset too large"
ADDL 433954697820(AX), AX // ERROR "offset too large"
ADDW 433954697820(AX), AX // ERROR "offset too large"
// Pseudo-registers should not be used as scaled index.
CALL (AX)(PC*1) // ERROR "invalid instruction"
CALL (AX)(SB*1) // ERROR "invalid instruction"
CALL (AX)(FP*1) // ERROR "invalid instruction"
RET

6
src/cmd/internal/obj/x86/asm6.go
View File

@ -2615,8 +2615,10 @@ func oclass(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) int {
return Yxxx
case obj.TYPE_MEM:
if a.Index == REG_SP {
// Can't use SP as the index register
// Pseudo registers have negative index, but SP is
// not pseudo on x86, hence REG_SP check is not redundant.
if a.Index == REG_SP || a.Index < 0 {
// Can't use FP/SB/PC/SP as the index register.
return Yxxx
}
if a.Index >= REG_X0 && a.Index <= REG_X15 {