[dev.link] cmd/link: remove duplicate asmb code

Lots of the architecture specific code for asmb() is very simimar. As
such, move to a common function.

Change-Id: Id1fd50ee7bfa1bc9978e3f42ad08914b04cd677b
Reviewed-on: https://go-review.googlesource.com/c/go/+/234683
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/cmd/link/internal/amd64/asm.go

@@ -38,7 +38,6 @@ import (
 	"cmd/link/internal/sym"
 	"debug/elf"
 	"log"
-	"sync"
 )
 
 func PADDR(x uint32) uint32 {
@@ -680,40 +679,6 @@ func addgotsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 	}
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	f := func(ctxt *ld.Link, out *ld.OutBuf, start, length int64) {
-		// 0xCC is INT $3 - breakpoint instruction
-		ld.CodeblkPad(ctxt, out, start, length, []byte{0xCC})
-	}
-	ld.WriteParallel(&wg, f, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect := range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	machlink := int64(0)
 	if ctxt.HeadType == objabi.Hdarwin {

src/cmd/link/internal/amd64/obj.go

@@ -50,12 +50,13 @@ func Init() (*sys.Arch, ld.Arch) {
 		Minalign:   minAlign,
 		Dwarfregsp: dwarfRegSP,
 		Dwarfreglr: dwarfRegLR,
+		// 0xCC is INT $3 - breakpoint instruction
+		CodePad: []byte{0xCC},
 
 		Adddynrel:        adddynrel,
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/arm/asm.go

@@ -39,7 +39,6 @@ import (
 	"debug/elf"
 	"fmt"
 	"log"
-	"sync"
 )
 
 // This assembler:
@@ -672,35 +671,6 @@ func addgotsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 	}
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	ld.WriteParallel(&wg, ld.Codeblk, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect := range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	/* output symbol table */
 	ld.Symsize = 0

src/cmd/link/internal/arm/obj.go

@@ -51,7 +51,6 @@ func Init() (*sys.Arch, ld.Arch) {
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
 		Trampoline:       trampoline,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/arm64/asm.go

@@ -39,7 +39,6 @@ import (
 	"debug/elf"
 	"fmt"
 	"log"
-	"sync"
 )
 
 func gentext(ctxt *ld.Link, ldr *loader.Loader) {
@@ -797,35 +796,6 @@ func addgotsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 	}
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	ld.WriteParallel(&wg, ld.Codeblk, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect := range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	machlink := uint32(0)
 	if ctxt.HeadType == objabi.Hdarwin {

src/cmd/link/internal/arm64/obj.go

@@ -50,7 +50,6 @@ func Init() (*sys.Arch, ld.Arch) {
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/ld/asmb.go

@@ -0,0 +1,70 @@
+// Copyright 2020 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 ld
+
+import (
+	"cmd/link/internal/loader"
+	"sync"
+)
+
+// Assembling the binary is broken into two steps:
+//  - writing out the code/data/dwarf Segments
+//  - writing out the architecture specific pieces.
+// This function handles the first part.
+func asmb(ctxt *Link, ldr *loader.Loader) {
+	// TODO(jfaller): delete me.
+	if thearch.Asmb != nil {
+		thearch.Asmb(ctxt, ldr)
+		return
+	}
+
+	if ctxt.IsELF {
+		Asmbelfsetup()
+	}
+
+	var wg sync.WaitGroup
+	sect := Segtext.Sections[0]
+	offset := sect.Vaddr - Segtext.Vaddr + Segtext.Fileoff
+	f := func(ctxt *Link, out *OutBuf, start, length int64) {
+		pad := thearch.CodePad
+		if pad == nil {
+			pad = zeros[:]
+		}
+		CodeblkPad(ctxt, out, start, length, pad)
+	}
+
+	if !thearch.WriteTextBlocks {
+		writeParallel(&wg, f, ctxt, offset, sect.Vaddr, sect.Length)
+		for _, sect := range Segtext.Sections[1:] {
+			offset := sect.Vaddr - Segtext.Vaddr + Segtext.Fileoff
+			writeParallel(&wg, Datblk, ctxt, offset, sect.Vaddr, sect.Length)
+		}
+	} else {
+		// TODO why can't we handle all sections this way?
+		for _, sect := range Segtext.Sections {
+			offset := sect.Vaddr - Segtext.Vaddr + Segtext.Fileoff
+			// Handle additional text sections with Codeblk
+			if sect.Name == ".text" {
+				writeParallel(&wg, f, ctxt, offset, sect.Vaddr, sect.Length)
+			} else {
+				writeParallel(&wg, Datblk, ctxt, offset, sect.Vaddr, sect.Length)
+			}
+		}
+	}
+
+	if Segrodata.Filelen > 0 {
+		writeParallel(&wg, Datblk, ctxt, Segrodata.Fileoff, Segrodata.Vaddr, Segrodata.Filelen)
+	}
+
+	if Segrelrodata.Filelen > 0 {
+		writeParallel(&wg, Datblk, ctxt, Segrelrodata.Fileoff, Segrelrodata.Vaddr, Segrelrodata.Filelen)
+	}
+
+	writeParallel(&wg, Datblk, ctxt, Segdata.Fileoff, Segdata.Vaddr, Segdata.Filelen)
+
+	writeParallel(&wg, dwarfblk, ctxt, Segdwarf.Fileoff, Segdwarf.Vaddr, Segdwarf.Filelen)
+
+	wg.Wait()
+}

src/cmd/link/internal/ld/data.go

@@ -801,10 +801,6 @@ func (state *dodataState) dynreloc(ctxt *Link) {
 	}
 }
 
-func Codeblk(ctxt *Link, out *OutBuf, addr int64, size int64) {
-	CodeblkPad(ctxt, out, addr, size, zeros[:])
-}
-
 func CodeblkPad(ctxt *Link, out *OutBuf, addr int64, size int64, pad []byte) {
 	writeBlocks(out, ctxt.outSem, ctxt.loader, ctxt.Textp, addr, size, pad)
 }
@@ -951,8 +947,8 @@ func writeBlock(out *OutBuf, ldr *loader.Loader, syms []loader.Sym, addr, size i
 
 type writeFn func(*Link, *OutBuf, int64, int64)
 
-// WriteParallel handles scheduling parallel execution of data write functions.
+// writeParallel handles scheduling parallel execution of data write functions.
-func WriteParallel(wg *sync.WaitGroup, fn writeFn, ctxt *Link, seek, vaddr, length uint64) {
+func writeParallel(wg *sync.WaitGroup, fn writeFn, ctxt *Link, seek, vaddr, length uint64) {
 	if out, err := ctxt.Out.View(seek); err != nil {
 		ctxt.Out.SeekSet(int64(seek))
 		fn(ctxt, ctxt.Out, int64(vaddr), int64(length))
@@ -981,7 +977,7 @@ func writeDatblkToOutBuf(ctxt *Link, out *OutBuf, addr int64, size int64) {
 	writeBlocks(out, ctxt.outSem, ctxt.loader, ctxt.datap, addr, size, zeros[:])
 }
 
-func Dwarfblk(ctxt *Link, out *OutBuf, addr int64, size int64) {
+func dwarfblk(ctxt *Link, out *OutBuf, addr int64, size int64) {
 	// Concatenate the section symbol lists into a single list to pass
 	// to writeBlocks.
 	//

src/cmd/link/internal/ld/lib.go

@@ -184,8 +184,18 @@ type Arch struct {
 	Openbsddynld   string
 	Dragonflydynld string
 	Solarisdynld   string
-	Adddynrel      func(*Target, *loader.Loader, *ArchSyms, loader.Sym, loader.Reloc2, int) bool
+
-	Archinit       func(*Link)
+	// Empty spaces between codeblocks will be padded with this value.
+	// For example an architecture might want to pad with a trap instruction to
+	// catch wayward programs. Architectures that do not define a padding value
+	// are padded with zeros.
+	CodePad []byte
+
+	// Set to true to write all text blocks in with CodeBlkWrite
+	WriteTextBlocks bool
+
+	Adddynrel func(*Target, *loader.Loader, *ArchSyms, loader.Sym, loader.Reloc2, int) bool
+	Archinit  func(*Link)
 	// Archreloc is an arch-specific hook that assists in relocation processing
 	// (invoked by 'relocsym'); it handles target-specific relocation tasks.
 	// Here "rel" is the current relocation being examined, "sym" is the symbol
@@ -212,10 +222,13 @@ type Arch struct {
 	// index of the relocation.
 	Trampoline func(ctxt *Link, ldr *loader.Loader, ri int, rs, s loader.Sym)
 
-	// Asmb and Asmb2 are arch-specific routines that write the output
+	// Assembling the binary breaks into two phases, writing the code/data/
-	// file. Typically, Asmb writes most of the content (sections and
+	// dwarf information (which is rather generic), and some more architecture
-	// segments), for which we have computed the size and offset. Asmb2
+	// specific work like setting up the elf headers/dynamic relocations, etc.
-	// writes the rest.
+	// The phases are called "Asmb" and "Asmb2". Asmb2 needs to be defined for
+	// every architecture, but only if architecture has an Asmb function will
+	// it be used for assembly.  Otherwise a generic assembly Asmb function is
+	// used.
 	Asmb  func(*Link, *loader.Loader)
 	Asmb2 func(*Link, *loader.Loader)
 

src/cmd/link/internal/ld/main.go

@@ -313,11 +313,11 @@ func Main(arch *sys.Arch, theArch Arch) {
 			panic(err)
 		}
 	}
-	// Asmb will redirect symbols to the output file mmap, and relocations
+	// asmb will redirect symbols to the output file mmap, and relocations
 	// will be applied directly there.
 	bench.Start("Asmb")
 	ctxt.loader.InitOutData()
-	thearch.Asmb(ctxt, ctxt.loader)
+	asmb(ctxt, ctxt.loader)
 	bench.Start("reloc")
 	ctxt.reloc()
 	bench.Start("Asmb2")

src/cmd/link/internal/mips/asm.go

@@ -38,7 +38,6 @@ import (
 	"cmd/link/internal/sym"
 	"debug/elf"
 	"fmt"
-	"sync"
 )
 
 func gentext(ctxt *ld.Link, ldr *loader.Loader) {
@@ -153,31 +152,6 @@ func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc2, sym.RelocVarian
 	return -1
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	ld.WriteParallel(&wg, ld.Codeblk, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect = range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	/* output symbol table */
 	ld.Symsize = 0

src/cmd/link/internal/mips/obj.go

@@ -52,7 +52,6 @@ func Init() (*sys.Arch, ld.Arch) {
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/mips64/asm.go

@@ -38,7 +38,6 @@ import (
 	"cmd/link/internal/sym"
 	"debug/elf"
 	"fmt"
-	"sync"
 )
 
 func gentext(ctxt *ld.Link, ldr *loader.Loader) {}
@@ -159,35 +158,6 @@ func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc2, sym.RelocVarian
 	return -1
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	ld.WriteParallel(&wg, ld.Codeblk, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect := range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	/* output symbol table */
 	ld.Symsize = 0

src/cmd/link/internal/mips64/obj.go

@@ -51,7 +51,6 @@ func Init() (*sys.Arch, ld.Arch) {
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/ppc64/asm.go

@@ -41,7 +41,6 @@ import (
 	"fmt"
 	"log"
 	"strings"
-	"sync"
 )
 
 func genplt(ctxt *ld.Link, ldr *loader.Loader) {
@@ -1081,36 +1080,6 @@ func ensureglinkresolver(ctxt *ld.Link, ldr *loader.Loader) *loader.SymbolBuilde
 	return glink
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	for _, sect := range ld.Segtext.Sections {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		// Handle additional text sections with Codeblk
-		if sect.Name == ".text" {
-			ld.WriteParallel(&wg, ld.Codeblk, ctxt, offset, sect.Vaddr, sect.Length)
-		} else {
-			ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-		}
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	/* output symbol table */
 	ld.Symsize = 0

src/cmd/link/internal/ppc64/obj.go

@@ -43,17 +43,17 @@ func Init() (*sys.Arch, ld.Arch) {
 	}
 
 	theArch := ld.Arch{
-		Funcalign:  funcAlign,
+		Funcalign:       funcAlign,
-		Maxalign:   maxAlign,
+		Maxalign:        maxAlign,
-		Minalign:   minAlign,
+		Minalign:        minAlign,
-		Dwarfregsp: dwarfRegSP,
+		Dwarfregsp:      dwarfRegSP,
-		Dwarfreglr: dwarfRegLR,
+		Dwarfreglr:      dwarfRegLR,
+		WriteTextBlocks: true,
 
 		Adddynrel:        adddynrel,
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/riscv64/asm.go

@@ -13,7 +13,6 @@ import (
 	"cmd/link/internal/sym"
 	"fmt"
 	"log"
-	"sync"
 )
 
 func gentext(ctxt *ld.Link, ldr *loader.Loader) {
@@ -91,35 +90,6 @@ func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc2, sym.RelocVarian
 	return -1
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	ld.WriteParallel(&wg, ld.Codeblk, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect := range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	ld.Symsize = 0
 	ld.Lcsize = 0

src/cmd/link/internal/riscv64/obj.go

@@ -23,7 +23,6 @@ func Init() (*sys.Arch, ld.Arch) {
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/s390x/asm.go

@@ -38,7 +38,6 @@ import (
 	"cmd/link/internal/sym"
 	"debug/elf"
 	"fmt"
-	"sync"
 )
 
 // gentext generates assembly to append the local moduledata to the global
@@ -477,35 +476,6 @@ func addgotsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 	}
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	ld.WriteParallel(&wg, ld.Codeblk, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect := range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	/* output symbol table */
 	ld.Symsize = 0

src/cmd/link/internal/s390x/obj.go

@@ -50,7 +50,6 @@ func Init() (*sys.Arch, ld.Arch) {
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,

src/cmd/link/internal/x86/asm.go

@@ -38,7 +38,6 @@ import (
 	"cmd/link/internal/sym"
 	"debug/elf"
 	"log"
-	"sync"
 )
 
 func gentext(ctxt *ld.Link, ldr *loader.Loader) {
@@ -511,38 +510,6 @@ func addgotsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 	}
 }
 
-func asmb(ctxt *ld.Link, _ *loader.Loader) {
-	if ctxt.IsELF {
-		ld.Asmbelfsetup()
-	}
-
-	var wg sync.WaitGroup
-	sect := ld.Segtext.Sections[0]
-	offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-	f := func(ctxt *ld.Link, out *ld.OutBuf, start, length int64) {
-		ld.CodeblkPad(ctxt, out, start, length, []byte{0xCC})
-	}
-	ld.WriteParallel(&wg, f, ctxt, offset, sect.Vaddr, sect.Length)
-
-	for _, sect := range ld.Segtext.Sections[1:] {
-		offset := sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, offset, sect.Vaddr, sect.Length)
-	}
-
-	if ld.Segrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrodata.Fileoff, ld.Segrodata.Vaddr, ld.Segrodata.Filelen)
-	}
-
-	if ld.Segrelrodata.Filelen > 0 {
-		ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segrelrodata.Fileoff, ld.Segrelrodata.Vaddr, ld.Segrelrodata.Filelen)
-	}
-
-	ld.WriteParallel(&wg, ld.Datblk, ctxt, ld.Segdata.Fileoff, ld.Segdata.Vaddr, ld.Segdata.Filelen)
-
-	ld.WriteParallel(&wg, ld.Dwarfblk, ctxt, ld.Segdwarf.Fileoff, ld.Segdwarf.Vaddr, ld.Segdwarf.Filelen)
-	wg.Wait()
-}
-
 func asmb2(ctxt *ld.Link, _ *loader.Loader) {
 	machlink := uint32(0)
 	if ctxt.HeadType == objabi.Hdarwin {

src/cmd/link/internal/x86/obj.go

@@ -45,12 +45,13 @@ func Init() (*sys.Arch, ld.Arch) {
 		Minalign:   minAlign,
 		Dwarfregsp: dwarfRegSP,
 		Dwarfreglr: dwarfRegLR,
+		// 0xCC is INT $3 - breakpoint instruction
+		CodePad: []byte{0xCC},
 
 		Adddynrel:        adddynrel,
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
-		Asmb:             asmb,
 		Asmb2:            asmb2,
 		Elfreloc1:        elfreloc1,
 		Elfsetupplt:      elfsetupplt,