From be1da9cdeecba15d0f68b4dcc145bcc77c0c4ace Mon Sep 17 00:00:00 2001
From: Cherry Zhang <cherryyz@google.com>
Date: Sat, 1 May 2021 15:00:03 -0400
Subject: [PATCH] cmd/link: unify text segment write

Currently we have two code paths of writing the text segment. They
are semantically the same:

- if we split text sections, we write all ".text" sections as
  text and the the rest as data.
- if we do not split text sections, we write the first section
  as text and the rest as data. The first section is named ".text"
  and is the only one in this case.

Unify the code.

Change-Id: Ic639eed625615be3c8a8d41f5b47e901552f587a
Reviewed-on: https://go-review.googlesource.com/c/go/+/316049
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
---
 src/cmd/link/internal/ld/asmb.go   | 23 ++++++-----------------
 src/cmd/link/internal/ld/lib.go    |  3 ---
 src/cmd/link/internal/ppc64/obj.go | 13 ++++++-------
 3 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/src/cmd/link/internal/ld/asmb.go b/src/cmd/link/internal/ld/asmb.go
index fda0439455..3754669555 100644
--- a/src/cmd/link/internal/ld/asmb.go
+++ b/src/cmd/link/internal/ld/asmb.go
@@ -29,8 +29,6 @@ func asmb(ctxt *Link) {
 	}
 
 	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 {
@@ -39,23 +37,14 @@ func asmb(ctxt *Link) {
 		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
+	for _, sect := range Segtext.Sections {
+		offset := sect.Vaddr - Segtext.Vaddr + Segtext.Fileoff
+		// Handle 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)
 		}
-	} 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 {
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index fd687df9ef..e8f001ba8e 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -203,9 +203,6 @@ type Arch struct {
 	// are padded with zeros.
 	CodePad []byte
 
-	// Set to true to write all text blocks in with CodeBlkWrite
-	WriteTextBlocks bool
-
 	// Plan 9 variables.
 	Plan9Magic  uint32
 	Plan9_64Bit bool
diff --git a/src/cmd/link/internal/ppc64/obj.go b/src/cmd/link/internal/ppc64/obj.go
index f56fa76b5b..b6d5ad92af 100644
--- a/src/cmd/link/internal/ppc64/obj.go
+++ b/src/cmd/link/internal/ppc64/obj.go
@@ -44,13 +44,12 @@ func Init() (*sys.Arch, ld.Arch) {
 	}
 
 	theArch := ld.Arch{
-		Funcalign:       funcAlign,
-		Maxalign:        maxAlign,
-		Minalign:        minAlign,
-		Dwarfregsp:      dwarfRegSP,
-		Dwarfreglr:      dwarfRegLR,
-		TrampLimit:      0x1c00000,
-		WriteTextBlocks: true,
+		Funcalign:  funcAlign,
+		Maxalign:   maxAlign,
+		Minalign:   minAlign,
+		Dwarfregsp: dwarfRegSP,
+		Dwarfreglr: dwarfRegLR,
+		TrampLimit: 0x1c00000,
 
 		Adddynrel:        adddynrel,
 		Archinit:         archinit,