5l, 6l, 8l: implement -X flag

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/5643050

10 files changed, 103 insertions, 130 deletions

diff --git a/src/cmd/5l/doc.go b/src/cmd/5l/doc.go
index aa7ccebfc9..969f502a7b 100644
--- a/src/cmd/5l/doc.go
+++ b/src/cmd/5l/doc.go
@@ -4,36 +4,10 @@
 
 /*
 
-5l is a modified version of the Plan 9 linker.  The original is documented at
+5l is the linker for the ARM.
+The $GOARCH for these tools is arm.
 
-	http://plan9.bell-labs.com/magic/man2html/1/2l
-
-Its target architecture is the ARM, referred to by these tools as arm.
-It reads files in .5 format generated by 5g, 5c, and 5a and emits
-a binary called 5.out by default.
-
-Major changes include:
-	- support for segmented stacks (this feature is implemented here, not in the compilers).
-
-
-Original options are listed in the link above.
-
-Options new in this version:
-
--F
-	Force use of software floating point.
-	Also implied by setting GOARM=5 in the environment.
--Hlinux
-	Write Linux ELF binaries (default when $GOOS is linux)
--I interpreter
-	Set the ELF dynamic linker to use.
--L dir1 -L dir2
-	Search for libraries (package files) in dir1, dir2, etc.
-	The default is the single location $GOROOT/pkg/$GOOS_arm.
--r dir1:dir2:...
-	Set the dynamic linker search path when using ELF.
--V
-	Print the linker version.
+The flags are documented in ../ld/doc.go.
 
 */
 package documentation
diff --git a/src/cmd/5l/obj.c b/src/cmd/5l/obj.c
index 03b106d4f0..0cc84d0eaf 100644
--- a/src/cmd/5l/obj.c
+++ b/src/cmd/5l/obj.c
@@ -81,7 +81,7 @@ void
 main(int argc, char *argv[])
 {
 	int c, i;
-	char *p;
+	char *p, *name, *val;
 
 	Binit(&bso, 1, OWRITE);
 	listinit();
@@ -92,6 +92,7 @@ main(int argc, char *argv[])
 	INITDAT = -1;
 	INITRND = -1;
 	INITENTRY = 0;
+	nuxiinit();
 	
 	p = getenv("GOARM");
 	if(p != nil && strcmp(p, "5") == 0)
@@ -137,9 +138,9 @@ main(int argc, char *argv[])
 		print("%cl version %s\n", thechar, getgoversion());
 		errorexit();
 	case 'X':
-		// TODO: golang.org/issue/2676
-		EARGF(usage());
-		EARGF(usage());
+		name = EARGF(usage());
+		val = EARGF(usage());
+		addstrdata(name, val);
 		break;
 	} ARGEND
 
@@ -240,7 +241,6 @@ main(int argc, char *argv[])
 	histgen = 0;
 	pc = 0;
 	dtype = 4;
-	nuxiinit();
 
 	version = 0;
 	cbp = buf.cbuf;
diff --git a/src/cmd/6l/doc.go b/src/cmd/6l/doc.go
index c18b0f29d5..4d94b209bc 100644
--- a/src/cmd/6l/doc.go
+++ b/src/cmd/6l/doc.go
@@ -4,49 +4,10 @@
 
 /*
 
-6l is a modified version of the Plan 9 linker.  The original is documented at
-
-	http://plan9.bell-labs.com/magic/man2html/1/2l
-
-Its target architecture is the x86-64, referred to by these tools as amd64.
-It reads files in .6 format generated by 6g, 6c, and 6a and emits
-a binary called 6.out by default.
-
-Major changes include:
-	- support for ELF and Mach-O binary files
-	- support for segmented stacks (this feature is implemented here, not in the compilers).
-
-
-Original options are listed in the link above.
-
-Options new in this version:
-
--d
-	Elide the dynamic linking header.  With this option, the binary
-	is statically linked and does not refer to dynld.  Without this option
-	(the default), the binary's contents are identical but it is loaded with dynld.
--Hdarwin
-	Write Apple Mach-O binaries (default when $GOOS is darwin)
--Hlinux
-	Write Linux ELF binaries (default when $GOOS is linux)
--Hfreebsd
-	Write FreeBSD ELF binaries (default when $GOOS is freebsd)
--Hnetbsd
-	Write NetBSD ELF binaries (default when $GOOS is netbsd)
--Hopenbsd
-	Write OpenBSD ELF binaries (default when $GOOS is openbsd)
--Hwindows
-	Write Windows PE32+ binaries (default when $GOOS is windows)
--I interpreter
-	Set the ELF dynamic linker to use.
--L dir1 -L dir2
-	Search for libraries (package files) in dir1, dir2, etc.
-	The default is the single location $GOROOT/pkg/$GOOS_amd64.
--r dir1:dir2:...
-	Set the dynamic linker search path when using ELF.
--V
-	Print the linker version.
+6l is the linker for the x86-64.
+The $GOARCH for these tools is amd64.
 
+The flags are documented in ../ld/doc.go.
 
 */
 package documentation
diff --git a/src/cmd/6l/obj.c b/src/cmd/6l/obj.c
index d258f05c9c..5305c4b797 100644
--- a/src/cmd/6l/obj.c
+++ b/src/cmd/6l/obj.c
@@ -82,6 +82,7 @@ void
 main(int argc, char *argv[])
 {
 	int c;
+	char *name, *val;
 
 	Binit(&bso, 1, OWRITE);
 	listinit();
@@ -93,6 +94,7 @@ main(int argc, char *argv[])
 	INITDAT = -1;
 	INITRND = -1;
 	INITENTRY = 0;
+	nuxiinit();
 
 	ARGBEGIN {
 	default:
@@ -133,9 +135,9 @@ main(int argc, char *argv[])
 		print("%cl version %s\n", thechar, getgoversion());
 		errorexit();
 	case 'X':
-		// TODO: golang.org/issue/2676
-		EARGF(usage());
-		EARGF(usage());
+		name = EARGF(usage());
+		val = EARGF(usage());
+		addstrdata(name, val);
 		break;
 	} ARGEND
 
@@ -253,7 +255,6 @@ main(int argc, char *argv[])
 	zprg.mode = 64;
 
 	pcstr = "%.6llux ";
-	nuxiinit();
 	histgen = 0;
 	pc = 0;
 	dtype = 4;
diff --git a/src/cmd/8l/doc.go b/src/cmd/8l/doc.go
index edd683823f..12301d4f2e 100644
--- a/src/cmd/8l/doc.go
+++ b/src/cmd/8l/doc.go
@@ -4,51 +4,10 @@
 
 /*
 
-8l is a modified version of the Plan 9 linker.  The original is documented at
-
-	http://plan9.bell-labs.com/magic/man2html/1/2l
-
-Its target architecture is the x86, referred to by these tools for historical reasons as 386.
-It reads files in .8 format generated by 8g, 8c, and 8a and emits
-a binary called 8.out by default.
-
-Major changes include:
-	- support for ELF and Mach-O binary files
-	- support for segmented stacks (this feature is implemented here, not in the compilers).
-
-
-Original options are listed in the link above.
-
-Options new in this version:
-
--d
-	Elide the dynamic linking header.  With this option, the binary
-	is statically linked and does not refer to dynld.  Without this option
-	(the default), the binary's contents are identical but it is loaded with dynld.
--Hplan9
-	Write Plan 9 32-bit format binaries (default when $GOOS is plan9)
--Hdarwin
-	Write Apple Mach-O binaries (default when $GOOS is darwin)
--Hlinux
-	Write Linux ELF binaries (default when $GOOS is linux)
--Hfreebsd
-	Write FreeBSD ELF binaries (default when $GOOS is freebsd)
--Hnetbsd
-	Write NetBSD ELF binaries (default when $GOOS is netbsd)
--Hopenbsd
-	Write OpenBSD ELF binaries (default when $GOOS is openbsd)
--Hwindows
-	Write Windows PE32 binaries (default when $GOOS is windows)
--I interpreter
-	Set the ELF dynamic linker to use.
--L dir1 -L dir2
-	Search for libraries (package files) in dir1, dir2, etc.
-	The default is the single location $GOROOT/pkg/$GOOS_386.
--r dir1:dir2:...
-	Set the dynamic linker search path when using ELF.
--V
-	Print the linker version.
+8l is the linker for the 32-bit x86.
+The $GOARCH for these tools is 386.
 
+The flags are documented in ../ld/doc.go.
 
 */
 package documentation
diff --git a/src/cmd/8l/obj.c b/src/cmd/8l/obj.c
index 1d0f1ec0fc..affdb57b7b 100644
--- a/src/cmd/8l/obj.c
+++ b/src/cmd/8l/obj.c
@@ -87,6 +87,7 @@ void
 main(int argc, char *argv[])
 {
 	int c;
+	char *name, *val;
 
 	Binit(&bso, 1, OWRITE);
 	listinit();
@@ -98,6 +99,7 @@ main(int argc, char *argv[])
 	INITDAT = -1;
 	INITRND = -1;
 	INITENTRY = 0;
+	nuxiinit();
 
 	ARGBEGIN {
 	default:
@@ -138,9 +140,9 @@ main(int argc, char *argv[])
 		print("%cl version %s\n", thechar, getgoversion());
 		errorexit();
 	case 'X':
-		// TODO: golang.org/issue/2676
-		EARGF(usage());
-		EARGF(usage());
+		name = EARGF(usage());
+		val = EARGF(usage());
+		addstrdata(name, val);
 		break;
 	} ARGEND
 
@@ -280,7 +282,6 @@ main(int argc, char *argv[])
 	zprg.to = zprg.from;
 
 	pcstr = "%.6ux ";
-	nuxiinit();
 	histgen = 0;
 	pc = 0;
 	dtype = 4;
diff --git a/src/cmd/ld/data.c b/src/cmd/ld/data.c
index d34d23c770..b5f1b99312 100644
--- a/src/cmd/ld/data.c
+++ b/src/cmd/ld/data.c
@@ -589,6 +589,25 @@ strnput(char *s, int n)
 	}
 }
 
+void
+addstrdata(char *name, char *value)
+{
+	Sym *s, *sp;
+	char *p;
+	
+	p = smprint("%s.str", name);
+	sp = lookup(p, 0);
+	free(p);
+	addstring(sp, value);
+
+	s = lookup(name, 0);
+	s->dupok = 1;
+	addaddr(s, sp);
+	adduint32(s, strlen(value));
+	if(PtrSize == 8)
+		adduint32(s, 0);  // round struct to pointer width
+}
+
 vlong
 addstring(Sym *s, char *str)
 {
diff --git a/src/cmd/ld/doc.go b/src/cmd/ld/doc.go
index 972e2a32c9..4728fccb8b 100644
--- a/src/cmd/ld/doc.go
+++ b/src/cmd/ld/doc.go
@@ -4,8 +4,50 @@
 
 /*
 
-This directory contains the portable section of the Plan 9 C linkers.
-See ../6l, ../8l, and ../5l for more information.
+Ld is the portable code for a modified version of the Plan 9 linker.  The original is documented at
+
+	http://plan9.bell-labs.com/magic/man2html/1/2l
+
+It reads object files (.5, .6, or .8 files) and writes a binary named for the
+architecture (5.out, 6.out, 8.out) by default.
+
+Major changes include:
+	- support for ELF and Mach-O binary files
+	- support for segmented stacks (this feature is implemented here, not in the compilers).
+
+Original options are listed on the manual page linked above.
+
+Options new in this version:
+
+-d
+	Elide the dynamic linking header.  With this option, the binary
+	is statically linked and does not refer to dynld.  Without this option
+	(the default), the binary's contents are identical but it is loaded with dynld.
+-Hdarwin
+	Write Apple Mach-O binaries (default when $GOOS is darwin)
+-Hlinux
+	Write Linux ELF binaries (default when $GOOS is linux)
+-Hfreebsd
+	Write FreeBSD ELF binaries (default when $GOOS is freebsd)
+-Hnetbsd
+	Write NetBSD ELF binaries (default when $GOOS is netbsd)
+-Hopenbsd
+	Write OpenBSD ELF binaries (default when $GOOS is openbsd)
+-Hwindows
+	Write Windows PE32+ binaries (default when $GOOS is windows)
+-I interpreter
+	Set the ELF dynamic linker to use.
+-L dir1 -L dir2
+	Search for libraries (package files) in dir1, dir2, etc.
+	The default is the single location $GOROOT/pkg/$GOOS_amd64.
+-r dir1:dir2:...
+	Set the dynamic linker search path when using ELF.
+-V
+	Print the linker version.
+-X symbol value
+	Set the value of an otherwise uninitialized string variable.
+	The symbol name should be of the form importpath.name,
+	as displayed in the symbol table printed by "go tool nm".
 
 */
 package documentation
diff --git a/src/cmd/ld/lib.h b/src/cmd/ld/lib.h
index bbaa52d43c..188ff9f928 100644
--- a/src/cmd/ld/lib.h
+++ b/src/cmd/ld/lib.h
@@ -179,6 +179,7 @@ void	reloc(void);
 void	relocsym(Sym*);
 void	savedata(Sym*, Prog*, char*);
 void	symgrow(Sym*, int32);
+void	addstrdata(char*, char*);
 vlong	addstring(Sym*, char*);
 vlong	adduint32(Sym*, uint32);
 vlong	adduint64(Sym*, uint64);
diff --git a/test/linkx.go b/test/linkx.go
new file mode 100644
index 0000000000..caa815a391
--- /dev/null
+++ b/test/linkx.go
@@ -0,0 +1,15 @@
+// $G $D/$F.go && $L -X main.tbd hello $F.$A && ./$A.out
+
+// Copyright 2012 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 main
+
+var tbd string
+
+func main() {
+	if tbd != "hello" {
+		println("BUG: test/linkx", len(tbd), tbd)
+	}
+}