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cmd/internal/obj/riscv: avoid obj.Prog rewriting for store instructions

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Rather than rewriting the obj.Prog for a store instruction, generate the
appropriate machine instruction sequence directly.

Change-Id: I026250ca3d249a1013243948a4e567b708b72d0c
Reviewed-on: https://go-review.googlesource.com/c/go/+/344452
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
This commit is contained in:
Joel Sing 2021-08-19 05:33:01 +00:00
parent 8a01010c26
commit 0b66310924
1 changed files with 38 additions and 37 deletions
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75
src/cmd/internal/obj/riscv/obj.go
View file

@ -794,37 +794,6 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
p.To = q.To
p.Reg = q.Reg
p.From = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP}
// <store> $imm, REG, TO (store $imm+(TO), REG)
case ASD, ASB, ASH, ASW, AFSW, AFSD:
low, high, err := Split32BitImmediate(p.To.Offset)
if err != nil {
ctxt.Diag("%v: constant %d too large", p, p.To.Offset)
}
if high == 0 {
break // no need to split
}
q := *p
// LUI $high, TMP
// ADD TMP, TO, TMP
// <store> $low, REG, TMP
p.As = ALUI
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: high}
p.Reg = 0
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP}
p.Spadj = 0 // needed if TO is SP
p = obj.Appendp(p, newprog)
p.As = AADD
p.From = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP}
p.Reg = q.To.Reg
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP}
p = obj.Appendp(p, newprog)
p.As = q.As
p.From = obj.Addr{Type: obj.TYPE_REG, Reg: q.From.Reg, Offset: 0}
p.To = obj.Addr{Type: obj.TYPE_MEM, Reg: REG_TMP, Offset: low}
}
}
@ -1817,6 +1786,43 @@ func instructionsForLoad(p *obj.Prog) []*instruction {
return []*instruction{insLUI, insADD, ins}
}
func instructionsForStore(p *obj.Prog) []*instruction {
if p.To.Type != obj.TYPE_MEM {
p.Ctxt.Diag("%v requires memory for destination", p)
return nil
}
switch p.As {
case ASW, ASH, ASB, ASD, AFSW, AFSD:
default:
p.Ctxt.Diag("%v: unknown store instruction %v", p, p.As)
return nil
}
// <store> $imm, REG, TO (store $imm+(TO), REG)
ins := instructionForProg(p)
ins.rs1, ins.rs2 = uint32(p.From.Reg), obj.REG_NONE
ins.imm = p.To.Offset
low, high, err := Split32BitImmediate(ins.imm)
if err != nil {
p.Ctxt.Diag("%v: constant %d too large", p, ins.imm)
return nil
}
if high == 0 {
return []*instruction{ins}
}
// LUI $high, TMP
// ADD TMP, TO, TMP
// <store> $low, REG, TMP
insLUI := &instruction{as: ALUI, rd: REG_TMP, imm: high}
insADD := &instruction{as: AADD, rd: REG_TMP, rs1: REG_TMP, rs2: ins.rd}
ins.rd, ins.imm = REG_TMP, low
return []*instruction{insLUI, insADD, ins}
}
// instructionsForMOV returns the machine instructions for an *obj.Prog that
// uses a MOV pseudo-instruction.
func instructionsForMOV(p *obj.Prog) []*instruction {
@ -1940,12 +1946,7 @@ func instructionsForProg(p *obj.Prog) []*instruction {
return instructionsForLoad(p)
case ASW, ASH, ASB, ASD, AFSW, AFSD:
if p.To.Type != obj.TYPE_MEM {
p.Ctxt.Diag("%v requires memory for destination", p)
return nil
}
ins.rs1, ins.rs2 = uint32(p.From.Reg), obj.REG_NONE
ins.imm = p.To.Offset
return instructionsForStore(p)
case ALRW, ALRD:
// Set aq to use acquire access ordering, which matches Go's memory requirements.