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cmd/internal/obj/riscv: store relocation details in obj.Prog.RestArgs

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Store the relocation offset and symbol in obj.Prog.RestArgs, rather than
overloading obj.Prog.From and having to deal with invalid offsets
potentially existing when the instruction is encoded.

Change-Id: Iff0d678361677e78b41b887f6eba08cee94fccb3
Reviewed-on: https://go-review.googlesource.com/c/go/+/218197
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Joel Sing 2020-02-06 04:47:52 +11:00
parent dad94e7c39
commit 2b920cba8f
1 changed files with 16 additions and 30 deletions
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46
src/cmd/internal/obj/riscv/obj.go
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@ -46,13 +46,12 @@ func jalrToSym(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc, lr int16) *ob
to := p.To
// This offset isn't really encoded with either instruction. It will be
// extracted for a relocation later.
p.As = AAUIPC
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: to.Offset, Sym: to.Sym}
p.Mark |= NEED_PCREL_ITYPE_RELOC
p.RestArgs = []obj.Addr{obj.Addr{Type: obj.TYPE_CONST, Offset: to.Offset, Sym: to.Sym}}
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: 0}
p.Reg = 0
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP}
p.Mark |= NEED_PCREL_ITYPE_RELOC
p = obj.Appendp(p, newprog)
// Leave Sym only for the CALL reloc in assemble.
@ -324,13 +323,12 @@ func rewriteMOV(ctxt *obj.Link, newprog obj.ProgAlloc, p *obj.Prog) {
as := p.As
to := p.To
// The offset is not really encoded with either instruction.
// It will be extracted later for a relocation.
p.As = AAUIPC
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: p.From.Offset, Sym: p.From.Sym}
p.Mark |= NEED_PCREL_ITYPE_RELOC
p.RestArgs = []obj.Addr{obj.Addr{Type: obj.TYPE_CONST, Offset: p.From.Offset, Sym: p.From.Sym}}
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: 0}
p.Reg = 0
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: to.Reg}
p.Mark |= NEED_PCREL_ITYPE_RELOC
p = obj.Appendp(p, newprog)
p.As = movToLoad(as)
@ -385,13 +383,12 @@ func rewriteMOV(ctxt *obj.Link, newprog obj.ProgAlloc, p *obj.Prog) {
as := p.As
from := p.From
// The offset is not really encoded with either instruction.
// It will be extracted later for a relocation.
p.As = AAUIPC
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: p.To.Offset, Sym: p.To.Sym}
p.Mark |= NEED_PCREL_STYPE_RELOC
p.RestArgs = []obj.Addr{obj.Addr{Type: obj.TYPE_CONST, Offset: p.To.Offset, Sym: p.To.Sym}}
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: 0}
p.Reg = 0
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP}
p.Mark |= NEED_PCREL_STYPE_RELOC
p = obj.Appendp(p, newprog)
p.As = movToStore(as)
@ -452,13 +449,12 @@ func rewriteMOV(ctxt *obj.Link, newprog obj.ProgAlloc, p *obj.Prog) {
// ADDI $off_lo, R
to := p.To
// The offset is not really encoded with either instruction.
// It will be extracted later for a relocation.
p.As = AAUIPC
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: p.From.Offset, Sym: p.From.Sym}
p.Mark |= NEED_PCREL_ITYPE_RELOC
p.RestArgs = []obj.Addr{obj.Addr{Type: obj.TYPE_CONST, Offset: p.From.Offset, Sym: p.From.Sym}}
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: 0}
p.Reg = 0
p.To = to
p.Mark |= NEED_PCREL_ITYPE_RELOC
p = obj.Appendp(p, newprog)
p.As = AADDI
@ -1413,13 +1409,6 @@ func validateB(p *obj.Prog) {
}
func validateU(p *obj.Prog) {
if p.As == AAUIPC && p.Mark&(NEED_PCREL_ITYPE_RELOC|NEED_PCREL_STYPE_RELOC) != 0 {
// TODO(sorear): Hack. The Offset is being used here to temporarily
// store the relocation addend, not as an actual offset to assemble,
// so it's OK for it to be out of range. Is there a more valid way
// to represent this state?
return
}
wantImmI(p, "from", p.From, 20)
wantIntRegAddr(p, "to", &p.To)
}
@ -1868,20 +1857,17 @@ func assemble(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
ctxt.Diag("AUIPC needing PC-relative reloc missing following instruction")
break
}
if p.From.Sym == nil {
addr := p.RestArgs[0]
if addr.Sym == nil {
ctxt.Diag("AUIPC needing PC-relative reloc missing symbol")
break
}
// The relocation offset can be larger than the maximum
// size of an AUIPC, so zero p.From.Offset to avoid any
// attempt to assemble it.
rel := obj.Addrel(cursym)
rel.Off = int32(p.Pc)
rel.Siz = 8
rel.Sym = p.From.Sym
rel.Add = p.From.Offset
p.From.Offset = 0
rel.Sym = addr.Sym
rel.Add = addr.Offset
rel.Type = rt
}