cmd/compile/internal: add spill support for loong64 regABI

Update #40724

Co-authored-by: Xiaolin Zhao <zhaoxiaolin@loongson.cn>
Change-Id: Ic01d59bd81420b89c6d4b90c5975bf069d08e7cc
Reviewed-on: https://go-review.googlesource.com/c/go/+/521780
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: David Chase <drchase@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Meidan Li <limeidan@loongson.cn>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: David Chase <drchase@google.com>

Author: 2 people

src/cmd/compile/internal/loong64/galign.go

@@ -20,4 +20,6 @@ func Init(arch *ssagen.ArchInfo) {
 	arch.SSAMarkMoves = func(s *ssagen.State, b *ssa.Block) {}
 	arch.SSAGenValue = ssaGenValue
 	arch.SSAGenBlock = ssaGenBlock
+	arch.LoadRegResult = loadRegResult
+	arch.SpillArgReg = spillArgReg
 }

src/cmd/compile/internal/loong64/ssa.go

@@ -10,6 +10,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/logopt"
+	"cmd/compile/internal/objw"
 	"cmd/compile/internal/ssa"
 	"cmd/compile/internal/ssagen"
 	"cmd/compile/internal/types"
@@ -145,6 +146,16 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.From.Reg = r
 		ssagen.AddrAuto(&p.To, v)
 	case ssa.OpArgIntReg, ssa.OpArgFloatReg:
+		// The assembler needs to wrap the entry safepoint/stack growth code with spill/unspill
+		// The loop only runs once.
+		for _, a := range v.Block.Func.RegArgs {
+			// Pass the spill/unspill information along to the assembler, offset by size of
+			// the saved LR slot.
+			addr := ssagen.SpillSlotAddr(a, loong64.REGSP, base.Ctxt.Arch.FixedFrameSize)
+			s.FuncInfo().AddSpill(
+				obj.RegSpill{Reg: a.Reg, Addr: addr, Unspill: loadByType(a.Type, a.Reg), Spill: storeByType(a.Type, a.Reg)})
+		}
+		v.Block.Func.RegArgs = nil
 		ssagen.CheckArgReg(v)
 	case ssa.OpLOONG64ADDV,
 		ssa.OpLOONG64SUBV,
@@ -370,7 +381,6 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Name = obj.NAME_EXTERN
 		p.To.Sym = ir.Syms.Duffzero
 		p.To.Offset = v.AuxInt
-
 	case ssa.OpLOONG64LoweredZero:
 		// MOVx	R0, (Rarg0)
 		// ADDV	$sz, Rarg0
@@ -799,3 +809,22 @@ func ssaGenBlock(s *ssagen.State, b, next *ssa.Block) {
 		b.Fatalf("branch not implemented: %s", b.LongString())
 	}
 }
+
+func loadRegResult(s *ssagen.State, f *ssa.Func, t *types.Type, reg int16, n *ir.Name, off int64) *obj.Prog {
+	p := s.Prog(loadByType(t, reg))
+	p.From.Type = obj.TYPE_MEM
+	p.From.Name = obj.NAME_AUTO
+	p.From.Sym = n.Linksym()
+	p.From.Offset = n.FrameOffset() + off
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = reg
+	return p
+}
+
+func spillArgReg(pp *objw.Progs, p *obj.Prog, f *ssa.Func, t *types.Type, reg int16, n *ir.Name, off int64) *obj.Prog {
+	p = pp.Append(p, storeByType(t, reg), obj.TYPE_REG, reg, 0, obj.TYPE_MEM, 0, n.FrameOffset()+off)
+	p.To.Name = obj.NAME_PARAM
+	p.To.Sym = n.Linksym()
+	p.Pos = p.Pos.WithNotStmt()
+	return p
+}