// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package riscv64

import (
	"cmd/internal/obj/riscv"
	"cmd/internal/objabi"
	"cmd/internal/sys"
	"cmd/link/internal/ld"
	"cmd/link/internal/loader"
	"cmd/link/internal/sym"
	"fmt"
	"log"
)

func gentext(ctxt *ld.Link, ldr *loader.Loader) {
}

func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, ri int, sectoff int64) bool {
	log.Fatalf("elfreloc1")
	return false
}

func elfsetupplt(ctxt *ld.Link, plt, gotplt *loader.SymbolBuilder, dynamic loader.Sym) {
	log.Fatalf("elfsetuplt")
}

func machoreloc1(*sys.Arch, *ld.OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool {
	log.Fatalf("machoreloc1 not implemented")
	return false
}

func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loader.Reloc, s loader.Sym, val int64) (o int64, nExtReloc int, ok bool) {
	rs := r.Sym()
	rs = ldr.ResolveABIAlias(rs)
	switch r.Type() {
	case objabi.R_CALLRISCV:
		// Nothing to do.
		return val, 0, true

	case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE:
		pc := ldr.SymValue(s) + int64(r.Off())
		off := ldr.SymValue(rs) + r.Add() - pc

		// Generate AUIPC and second instruction immediates.
		low, high, err := riscv.Split32BitImmediate(off)
		if err != nil {
			ldr.Errorf(s, "R_RISCV_PCREL_ relocation does not fit in 32-bits: %d", off)
		}

		auipcImm, err := riscv.EncodeUImmediate(high)
		if err != nil {
			ldr.Errorf(s, "cannot encode R_RISCV_PCREL_ AUIPC relocation offset for %s: %v", ldr.SymName(rs), err)
		}

		var secondImm, secondImmMask int64
		switch r.Type() {
		case objabi.R_RISCV_PCREL_ITYPE:
			secondImmMask = riscv.ITypeImmMask
			secondImm, err = riscv.EncodeIImmediate(low)
			if err != nil {
				ldr.Errorf(s, "cannot encode R_RISCV_PCREL_ITYPE I-type instruction relocation offset for %s: %v", ldr.SymName(rs), err)
			}
		case objabi.R_RISCV_PCREL_STYPE:
			secondImmMask = riscv.STypeImmMask
			secondImm, err = riscv.EncodeSImmediate(low)
			if err != nil {
				ldr.Errorf(s, "cannot encode R_RISCV_PCREL_STYPE S-type instruction relocation offset for %s: %v", ldr.SymName(rs), err)
			}
		default:
			panic(fmt.Sprintf("Unknown relocation type: %v", r.Type()))
		}

		auipc := int64(uint32(val))
		second := int64(uint32(val >> 32))

		auipc = (auipc &^ riscv.UTypeImmMask) | int64(uint32(auipcImm))
		second = (second &^ secondImmMask) | int64(uint32(secondImm))

		return second<<32 | auipc, 0, true
	}

	return val, 0, false
}

func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc, sym.RelocVariant, loader.Sym, int64) int64 {
	log.Fatalf("archrelocvariant")
	return -1
}