From 09cd0658750f798e295a0a38837ab899d2f3c030 Mon Sep 17 00:00:00 2001
From: Jeremy Faller <jeremy@golang.org>
Date: Tue, 28 Apr 2020 17:28:52 -0400
Subject: [PATCH] [dev.link] cmd/link: add archrelocsym x86 support for loader

Change-Id: I34822e5610caf537d62203fb6e0023c382a1e60a
Reviewed-on: https://go-review.googlesource.com/c/go/+/230678
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
---
 src/cmd/link/internal/ld/data.go | 35 ++++++++++++++++----------------
 src/cmd/link/internal/ld/lib.go  |  1 +
 src/cmd/link/internal/ld/main.go |  2 +-
 src/cmd/link/internal/x86/asm.go | 13 ++++++++++++
 src/cmd/link/internal/x86/obj.go |  1 +
 5 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 44e9b884ff..187f915a82 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -221,24 +221,23 @@ func relocsym(target *Target, ldr *loader.Loader, err *ErrorReporter, syms *Arch
 		var o int64
 		switch rt {
 		default:
-			panic("not implemented")
-			//switch siz {
-			//default:
-			//	err.Errorf(s, "bad reloc size %#x for %s", uint32(siz), ldr.SymName(rs))
-			//case 1:
-			//	o = int64(P[off])
-			//case 2:
-			//	o = int64(target.Arch.ByteOrder.Uint16(P[off:]))
-			//case 4:
-			//	o = int64(target.Arch.ByteOrder.Uint32(P[off:]))
-			//case 8:
-			//	o = int64(target.Arch.ByteOrder.Uint64(P[off:]))
-			//}
-			//if out, ok := thearch.Archreloc(ldr, target, syms, &r, s, o); ok {
-			//	o = out
-			//} else {
-			//	err.Errorf(s, "unknown reloc to %v: %d (%s)", ldr.SymName(rs), rt, sym.RelocName(target.Arch, rt))
-			//}
+			switch siz {
+			default:
+				err.Errorf(s, "bad reloc size %#x for %s", uint32(siz), ldr.SymName(rs))
+			case 1:
+				o = int64(P[off])
+			case 2:
+				o = int64(target.Arch.ByteOrder.Uint16(P[off:]))
+			case 4:
+				o = int64(target.Arch.ByteOrder.Uint32(P[off:]))
+			case 8:
+				o = int64(target.Arch.ByteOrder.Uint64(P[off:]))
+			}
+			if out, ok := thearch.Archreloc2(target, ldr, syms, &r, s, o); ok {
+				o = out
+			} else {
+				err.Errorf(s, "unknown reloc to %v: %d (%s)", ldr.SymName(rs), rt, sym.RelocName(target.Arch, rt))
+			}
 		case objabi.R_TLS_LE:
 			//if target.IsExternal() && target.IsElf() {
 			//	r.Done = false
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 618faf2233..51d81eb28d 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -246,6 +246,7 @@ type Arch struct {
 	// success/failure (a failing value indicates a fatal error).
 	Archreloc func(target *Target, syms *ArchSyms, rel *sym.Reloc, sym *sym.Symbol,
 		offset int64) (relocatedOffset int64, success bool)
+	Archreloc2 func(*Target, *loader.Loader, *ArchSyms, *loader.Reloc2, loader.Sym, int64) (int64, bool)
 	// Archrelocvariant is a second arch-specific hook used for
 	// relocation processing; it handles relocations where r.Type is
 	// insufficient to describe the relocation (r.Variant !=
diff --git a/src/cmd/link/internal/ld/main.go b/src/cmd/link/internal/ld/main.go
index 84f40d9b81..1484ade313 100644
--- a/src/cmd/link/internal/ld/main.go
+++ b/src/cmd/link/internal/ld/main.go
@@ -326,7 +326,7 @@ func Main(arch *sys.Arch, theArch Arch) {
 	ctxt.loader.InitOutData()
 	thearch.Asmb(ctxt, ctxt.loader)
 
-	newreloc := ctxt.IsInternal() && ctxt.IsAMD64()
+	newreloc := ctxt.IsInternal() && (ctxt.IsAMD64() || ctxt.Is386())
 	if newreloc {
 		bench.Start("reloc")
 		ctxt.reloc()
diff --git a/src/cmd/link/internal/x86/asm.go b/src/cmd/link/internal/x86/asm.go
index 157e13496c..4e31c4e8ea 100644
--- a/src/cmd/link/internal/x86/asm.go
+++ b/src/cmd/link/internal/x86/asm.go
@@ -435,6 +435,19 @@ func pereloc1(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, secto
 	return true
 }
 
+func archreloc2(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r *loader.Reloc2, sym loader.Sym, val int64) (int64, bool) {
+	if target.IsExternal() {
+		return val, false
+	}
+	switch r.Type() {
+	case objabi.R_CONST:
+		return r.Add(), true
+	case objabi.R_GOTOFF:
+		return ldr.SymValue(r.Sym()) + r.Add() - ldr.SymValue(syms.GOT2), true
+	}
+	return val, false
+}
+
 func archreloc(target *ld.Target, syms *ld.ArchSyms, r *sym.Reloc, s *sym.Symbol, val int64) (int64, bool) {
 	if target.IsExternal() {
 		return val, false
diff --git a/src/cmd/link/internal/x86/obj.go b/src/cmd/link/internal/x86/obj.go
index 61e3077b5b..8686d6ec18 100644
--- a/src/cmd/link/internal/x86/obj.go
+++ b/src/cmd/link/internal/x86/obj.go
@@ -49,6 +49,7 @@ func Init() (*sys.Arch, ld.Arch) {
 		Adddynrel2:       adddynrel2,
 		Archinit:         archinit,
 		Archreloc:        archreloc,
+		Archreloc2:       archreloc2,
 		Archrelocvariant: archrelocvariant,
 		Asmb:             asmb,
 		Asmb2:            asmb2,