cmd/internal/obj,cmd/link: access global data via GOT in -dynlink mode on loong64

Updates #58784

Change-Id: Ic98d10a512fea0c3ca321ab52693d9f6775126a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/480875
Reviewed-by: 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: WANG Xuerui <git@xen0n.name>
Reviewed-by: WANG Xuerui <git@xen0n.name>

4 files changed, 140 insertions, 0 deletions

diff --git a/src/cmd/internal/obj/loong64/a.out.go b/src/cmd/internal/obj/loong64/a.out.go
index a4bb7b40a3..d944fcfcb8 100644
--- a/src/cmd/internal/obj/loong64/a.out.go
+++ b/src/cmd/internal/obj/loong64/a.out.go
@@ -227,6 +227,7 @@ const (
 	C_ADDR
 	C_TLS_LE
 	C_TLS_IE
+	C_GOTADDR
 	C_TEXTSIZE
 
 	C_NCLASS // must be the last
diff --git a/src/cmd/internal/obj/loong64/asm.go b/src/cmd/internal/obj/loong64/asm.go
index 19250c94ee..64c9226079 100644
--- a/src/cmd/internal/obj/loong64/asm.go
+++ b/src/cmd/internal/obj/loong64/asm.go
@@ -349,6 +349,8 @@ var optab = []Optab{
 	{AWORD, C_LCON, C_NONE, C_NONE, C_NONE, C_NONE, 40, 4, 0, 0},
 	{AWORD, C_DCON, C_NONE, C_NONE, C_NONE, C_NONE, 61, 4, 0, 0},
 
+	{AMOVV, C_GOTADDR, C_NONE, C_NONE, C_REG, C_NONE, 65, 8, 0, 0},
+
 	{ATEQ, C_SCON, C_REG, C_NONE, C_REG, C_NONE, 15, 8, 0, 0},
 	{ATEQ, C_SCON, C_NONE, C_NONE, C_REG, C_NONE, 15, 8, 0, 0},
 
@@ -676,6 +678,9 @@ func (c *ctxt0) aclass(a *obj.Addr) int {
 				return C_SOREG
 			}
 			return C_LOREG
+
+		case obj.NAME_GOTREF:
+			return C_GOTADDR
 		}
 
 		return C_GOK
@@ -1776,6 +1781,22 @@ func (c *ctxt0) asmout(p *obj.Prog, o *Optab, out []uint32) {
 	case 64: // movv c_reg, c_fcc0 ==> movgr2cf cd, rj
 		a := OP_TEN(8, 1334)
 		o1 = OP_RR(a, uint32(p.From.Reg), uint32(p.To.Reg))
+
+	case 65: // mov sym@GOT, r ==> pcalau12i + ld.d
+		o1 = OP_IR(c.opir(APCALAU12I), uint32(0), uint32(p.To.Reg))
+		rel := obj.Addrel(c.cursym)
+		rel.Off = int32(c.pc)
+		rel.Siz = 4
+		rel.Sym = p.From.Sym
+		rel.Type = objabi.R_LOONG64_GOT_HI
+		rel.Add = 0x0
+		o2 = OP_12IRR(c.opirr(-p.As), uint32(0), uint32(p.To.Reg), uint32(p.To.Reg))
+		rel2 := obj.Addrel(c.cursym)
+		rel2.Off = int32(c.pc + 4)
+		rel2.Siz = 4
+		rel2.Sym = p.From.Sym
+		rel2.Type = objabi.R_LOONG64_GOT_LO
+		rel2.Add = 0x0
 	}
 
 	out[0] = o1
diff --git a/src/cmd/internal/obj/loong64/cnames.go b/src/cmd/internal/obj/loong64/cnames.go
index 8b8af6ba31..94b1b54c93 100644
--- a/src/cmd/internal/obj/loong64/cnames.go
+++ b/src/cmd/internal/obj/loong64/cnames.go
@@ -39,6 +39,7 @@ var cnames0 = []string{
 	"ADDR",
 	"TLS_LE",
 	"TLS_IE",
+	"GOTADDR",
 	"TEXTSIZE",
 	"NCLASS",
 }
diff --git a/src/cmd/internal/obj/loong64/obj.go b/src/cmd/internal/obj/loong64/obj.go
index d15d0dfd4c..fe98f8c11b 100644
--- a/src/cmd/internal/obj/loong64/obj.go
+++ b/src/cmd/internal/obj/loong64/obj.go
@@ -6,6 +6,7 @@ package loong64
 
 import (
 	"cmd/internal/obj"
+	"cmd/internal/objabi"
 	"cmd/internal/sys"
 	"internal/abi"
 	"log"
@@ -84,6 +85,122 @@ func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {
 			p.As = AADDVU
 		}
 	}
+
+	if ctxt.Flag_dynlink {
+		rewriteToUseGot(ctxt, p, newprog)
+	}
+}
+
+func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {
+	//     ADUFFxxx $offset
+	// becomes
+	//     MOVV runtime.duffxxx@GOT, REGTMP
+	//     ADD $offset, REGTMP
+	//     JAL REGTMP
+	if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
+		var sym *obj.LSym
+		if p.As == obj.ADUFFZERO {
+			sym = ctxt.Lookup("runtime.duffzero")
+		} else {
+			sym = ctxt.Lookup("runtime.duffcopy")
+		}
+		offset := p.To.Offset
+		p.As = AMOVV
+		p.From.Type = obj.TYPE_MEM
+		p.From.Sym = sym
+		p.From.Name = obj.NAME_GOTREF
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGTMP
+		p.To.Name = obj.NAME_NONE
+		p.To.Offset = 0
+		p.To.Sym = nil
+		p1 := obj.Appendp(p, newprog)
+		p1.As = AADDV
+		p1.From.Type = obj.TYPE_CONST
+		p1.From.Offset = offset
+		p1.To.Type = obj.TYPE_REG
+		p1.To.Reg = REGTMP
+		p2 := obj.Appendp(p1, newprog)
+		p2.As = AJAL
+		p2.To.Type = obj.TYPE_MEM
+		p2.To.Reg = REGTMP
+	}
+
+	// We only care about global data: NAME_EXTERN means a global
+	// symbol in the Go sense, and p.Sym.Local is true for a few
+	// internally defined symbols.
+	if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
+		// MOVV $sym, Rx becomes MOVV sym@GOT, Rx
+		// MOVV $sym+<off>, Rx becomes MOVV sym@GOT, Rx; ADD <off>, Rx
+		if p.As != AMOVV {
+			ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -shared", p)
+		}
+		if p.To.Type != obj.TYPE_REG {
+			ctxt.Diag("do not know how to handle LEAQ-type insn to non-register in %v with -shared", p)
+		}
+		p.From.Type = obj.TYPE_MEM
+		p.From.Name = obj.NAME_GOTREF
+		if p.From.Offset != 0 {
+			q := obj.Appendp(p, newprog)
+			q.As = AADDV
+			q.From.Type = obj.TYPE_CONST
+			q.From.Offset = p.From.Offset
+			q.To = p.To
+			p.From.Offset = 0
+		}
+	}
+	if p.GetFrom3() != nil && p.GetFrom3().Name == obj.NAME_EXTERN {
+		ctxt.Diag("don't know how to handle %v with -shared", p)
+	}
+
+	var source *obj.Addr
+	// MOVx sym, Ry becomes MOVV sym@GOT, REGTMP; MOVx (REGTMP), Ry
+	// MOVx Ry, sym becomes MOVV sym@GOT, REGTMP; MOVx Ry, (REGTMP)
+	// An addition may be inserted between the two MOVs if there is an offset.
+	if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
+		if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
+			ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -shared", p)
+		}
+		source = &p.From
+	} else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
+		source = &p.To
+	} else {
+		return
+	}
+	if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
+		return
+	}
+	if source.Sym.Type == objabi.STLSBSS {
+		return
+	}
+	if source.Type != obj.TYPE_MEM {
+		ctxt.Diag("don't know how to handle %v with -shared", p)
+	}
+	p1 := obj.Appendp(p, newprog)
+	p2 := obj.Appendp(p1, newprog)
+	p1.As = AMOVV
+	p1.From.Type = obj.TYPE_MEM
+	p1.From.Sym = source.Sym
+	p1.From.Name = obj.NAME_GOTREF
+	p1.To.Type = obj.TYPE_REG
+	p1.To.Reg = REGTMP
+
+	p2.As = p.As
+	p2.From = p.From
+	p2.To = p.To
+	if p.From.Name == obj.NAME_EXTERN {
+		p2.From.Reg = REGTMP
+		p2.From.Name = obj.NAME_NONE
+		p2.From.Sym = nil
+	} else if p.To.Name == obj.NAME_EXTERN {
+		p2.To.Reg = REGTMP
+		p2.To.Name = obj.NAME_NONE
+		p2.To.Sym = nil
+	} else {
+		return
+	}
+
+	obj.Nopout(p)
 }
 
 func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {