From e97b3ab1f942a1bb2812e6b5c890c052903fa0b0 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Tue, 15 Apr 2014 20:46:46 -0400
Subject: [PATCH] build: remove tmp dir names from objects, support
 GOROOT_FINAL again

If we compile a generated file stored in a temporary
directory - let's say /tmp/12345/work/x.c - then by default
6c stores the full path and then the pcln table in the
final binary includes the full path. This makes repeated builds
(using different temporary directories) produce different
binaries, even if the inputs are the same.

In the old 'go tool pack', the P flag specified a prefix to remove
from all stored paths (if present), and cmd/go invoked
'go tool pack grcP $WORK' to remove references to the
temporary work directory.

We've changed the build to avoid pack as much as possible,
under the theory that instead of making pack convert from
.6 to .a, the tools should just write the .a directly and save a
round of I/O.

Instead of going back to invoking pack always, define a common
flag -trimpath in the assemblers, C compilers, and Go compilers,
implemented in liblink, and arrange for cmd/go to use the flag.
Then the object files being written out have the shortened paths
from the start.

While we are here, reimplement pcln support for GOROOT_FINAL.
A build in /tmp/go uses GOROOT=/tmp/go, but if GOROOT_FINAL=/usr/local/go
is set, then a source file named /tmp/go/x.go is recorded instead as
/usr/local/go/x.go. We use this so that we can prepare distributions
to be installed in /usr/local/go without actually working in that
directory. The conversion to liblink deleted all the old file name
handling code, including the GOROOT_FINAL translation.
Bring the GOROOT_FINAL translation back.

Before this CL, using GOROOT_FINAL=/goroot make.bash:

        g% strings $(which go) | grep -c $TMPDIR
        6
        g% strings $(which go) | grep -c $GOROOT
        793
        g%

After this CL:

        g% strings $(which go) | grep -c $TMPDIR
        0
        g% strings $(which go) | grep -c $GOROOT
        0
        g%

(The references to $TMPDIR tend to be cgo-generated source files.)

Adding the -trimpath flag to the assemblers required converting
them to the new Go-semantics flag parser. The text in go1.3.html
is copied and adjusted from go1.1.html, which is when we applied
that conversion to the compilers and linkers.

Fixes #6989.

LGTM=iant
R=r, iant
CC=golang-codereviews
https://golang.org/cl/88300045
---
 doc/go1.3.html      | 13 +++++++++
 include/link.h      |  3 ++
 src/cmd/5a/a.h      |  2 +-
 src/cmd/5a/lex.c    | 71 ++++++++++++++++++++-------------------------
 src/cmd/6a/a.h      |  2 +-
 src/cmd/6a/lex.c    | 63 ++++++++++++++++++----------------------
 src/cmd/8a/a.h      |  2 +-
 src/cmd/8a/lex.c    | 65 +++++++++++++++++++----------------------
 src/cmd/cc/lex.c    |  1 +
 src/cmd/gc/lex.c    |  1 +
 src/cmd/go/build.go |  8 ++---
 src/liblink/obj.c   | 46 ++++++++++++++++++++++++++++-
 src/liblink/sym.c   |  4 +++
 13 files changed, 164 insertions(+), 117 deletions(-)

diff --git a/doc/go1.3.html b/doc/go1.3.html
index 10073200c4..916ed04d25 100644
--- a/doc/go1.3.html
+++ b/doc/go1.3.html
@@ -145,6 +145,19 @@ Finally, the go command now supports packages that import Objective-C
 files (suffixed <code>.m</code>) through cgo.
 </p>
 
+<h3 id="gc_flag">Command-line flag parsing</h3>
+
+<p>
+In the gc tool chain, the assemblers now use the
+same command-line flag parsing rules as the Go flag package, a departure
+from the traditional Unix flag parsing. This may affect scripts that invoke
+the tool directly.
+For example,
+<code>go tool 6a -SDfoo</code> must now be written
+<code>go tool 6a -S -D foo</code>.
+(The same change was made to the compilers and linkers in <a href="/doc/go1.1#gc_flag">Go 1.1</a>.)
+</p>
+
 <h3 id="misc">Miscellany</h3>
 
 <p>
diff --git a/include/link.h b/include/link.h
index 9a6fca2ab0..200a503cce 100644
--- a/include/link.h
+++ b/include/link.h
@@ -360,6 +360,9 @@ struct	Link
 	Biobuf*	bso;	// for -v flag
 	char*	pathname;
 	int32	windows;
+	char*	trimpath;
+	char*	goroot;
+	char*	goroot_final;
 
 	// hash table of all symbols
 	LSym*	hash[LINKHASH];
diff --git a/src/cmd/5a/a.h b/src/cmd/5a/a.h
index 4300dd8621..bb60fe7de2 100644
--- a/src/cmd/5a/a.h
+++ b/src/cmd/5a/a.h
@@ -97,7 +97,7 @@ enum
 	Always	= 14,
 };
 
-EXTERN	char	debug[256];
+EXTERN	int	debug[256];
 EXTERN	Sym*	hash[NHASH];
 EXTERN	char**	Dlist;
 EXTERN	int	nDlist;
diff --git a/src/cmd/5a/lex.c b/src/cmd/5a/lex.c
index 211f7538b5..906eee641a 100644
--- a/src/cmd/5a/lex.c
+++ b/src/cmd/5a/lex.c
@@ -57,11 +57,27 @@ Lconv(Fmt *fp)
 	return linklinefmt(ctxt, fp);
 }
 
+void
+dodef(char *p)
+{
+	if(nDlist%8 == 0)
+		Dlist = allocn(Dlist, nDlist*sizeof(char *),
+			8*sizeof(char *));
+	Dlist[nDlist++] = p;
+}
+
+void
+usage(void)
+{
+	print("usage: %ca [options] file.c...\n", thechar);
+	flagprint(1);
+	errorexit();
+}
+
 void
 main(int argc, char *argv[])
 {
 	char *p;
-	int c;
 
 	thechar = '5';
 	thestring = "arm";
@@ -84,49 +100,24 @@ main(int argc, char *argv[])
 	cinit();
 	outfile = 0;
 	setinclude(".");
-	ARGBEGIN {
-	default:
-		c = ARGC();
-		if(c >= 0 && c < sizeof(debug))
-			debug[c] = 1;
-		break;
-
-	case 'o':
-		outfile = ARGF();
-		break;
-
-	case 'D':
-		p = ARGF();
-		if(p) {
-			if (nDlist%8 == 0) 
-				Dlist = allocn(Dlist, nDlist*sizeof(char *), 
-					8*sizeof(char *));
-			Dlist[nDlist++] = p;
-		}
-		break;
-
-	case 'I':
-		p = ARGF();
-		setinclude(p);
-		break;
-
-	case 't':
-		thechar = 't';
-		thestring = "thumb";
-		break;
-
-	case 'S':
-		ctxt->debugasm++;
-		break;
-	} ARGEND
-	if(*argv == 0) {
-		print("usage: %ca [-options] file.s\n", thechar);
-		errorexit();
-	}
+	
+	flagfn1("D", "name[=value]: add #define", dodef);
+	flagfn1("I", "dir: add dir to include path", setinclude);
+	flagcount("S", "print assembly and machine code", &debug['S']);
+	flagcount("m", "debug preprocessor macros", &debug['m']);
+	flagstr("o", "file: set output file", &outfile);
+	flagstr("trimpath", "prefix: remove prefix from recorded source file paths", &ctxt->trimpath);
+
+	flagparse(&argc, &argv, usage);
+	ctxt->debugasm = debug['S'];
+
+	if(argc < 1)
+		usage();
 	if(argc > 1){
 		print("can't assemble multiple files\n");
 		errorexit();
 	}
+
 	if(assemble(argv[0]))
 		errorexit();
 	Bflush(&bstdout);
diff --git a/src/cmd/6a/a.h b/src/cmd/6a/a.h
index da12b32986..b3fb0bb19f 100644
--- a/src/cmd/6a/a.h
+++ b/src/cmd/6a/a.h
@@ -109,7 +109,7 @@ enum
 	CPREPROC,
 };
 
-EXTERN	char	debug[256];
+EXTERN	int	debug[256];
 EXTERN	Sym*	hash[NHASH];
 EXTERN	char**	Dlist;
 EXTERN	int	nDlist;
diff --git a/src/cmd/6a/lex.c b/src/cmd/6a/lex.c
index 2a1c4b8e1f..4ebcc175c3 100644
--- a/src/cmd/6a/lex.c
+++ b/src/cmd/6a/lex.c
@@ -63,13 +63,29 @@ Lconv(Fmt *fp)
 	return linklinefmt(ctxt, fp);
 }
 
+void
+dodef(char *p)
+{
+	if(nDlist%8 == 0)
+		Dlist = allocn(Dlist, nDlist*sizeof(char *),
+			8*sizeof(char *));
+	Dlist[nDlist++] = p;
+}
+
 LinkArch*       thelinkarch = &linkamd64;
 
+void
+usage(void)
+{
+	print("usage: %ca [options] file.c...\n", thechar);
+	flagprint(1);
+	errorexit();
+}
+
 void
 main(int argc, char *argv[])
 {
 	char *p;
-	int c;
 
 	thechar = '6';
 	thestring = "amd64";
@@ -94,45 +110,24 @@ main(int argc, char *argv[])
 	cinit();
 	outfile = 0;
 	setinclude(".");
-	ARGBEGIN {
-	default:
-		c = ARGC();
-		if(c >= 0 && c < sizeof(debug))
-			debug[c] = 1;
-		break;
-
-	case 'o':
-		outfile = ARGF();
-		break;
-
-	case 'D':
-		p = ARGF();
-		if(p) {
-			if (nDlist%8 == 0)
-				Dlist = allocn(Dlist, nDlist*sizeof(char *), 
-					8*sizeof(char *));
-			Dlist[nDlist++] = p;
-		}
-		break;
-
-	case 'I':
-		p = ARGF();
-		setinclude(p);
-		break;
+	
+	flagfn1("D", "name[=value]: add #define", dodef);
+	flagfn1("I", "dir: add dir to include path", setinclude);
+	flagcount("S", "print assembly and machine code", &debug['S']);
+	flagcount("m", "debug preprocessor macros", &debug['m']);
+	flagstr("o", "file: set output file", &outfile);
+	flagstr("trimpath", "prefix: remove prefix from recorded source file paths", &ctxt->trimpath);
 
-	case 'S':
-		ctxt->debugasm++;
-		break;
-	} ARGEND
+	flagparse(&argc, &argv, usage);
+	ctxt->debugasm = debug['S'];
 
-	if(*argv == 0) {
-		print("usage: %ca [-options] file.s\n", thechar);
-		errorexit();
-	}
+	if(argc < 1)
+		usage();
 	if(argc > 1){
 		print("can't assemble multiple files\n");
 		errorexit();
 	}
+
 	if(assemble(argv[0]))
 		errorexit();
 	Bflush(&bstdout);
diff --git a/src/cmd/8a/a.h b/src/cmd/8a/a.h
index 8c023c3ec6..adc388ca9f 100644
--- a/src/cmd/8a/a.h
+++ b/src/cmd/8a/a.h
@@ -109,7 +109,7 @@ enum
 	CPREPROC,
 };
 
-EXTERN	char	debug[256];
+EXTERN	int	debug[256];
 EXTERN	Sym*	hash[NHASH];
 EXTERN	char**	Dlist;
 EXTERN	int	nDlist;
diff --git a/src/cmd/8a/lex.c b/src/cmd/8a/lex.c
index 49a105da6a..79a9488e4b 100644
--- a/src/cmd/8a/lex.c
+++ b/src/cmd/8a/lex.c
@@ -63,11 +63,26 @@ Lconv(Fmt *fp)
 	return linklinefmt(ctxt, fp);
 }
 
+void
+dodef(char *p)
+{
+	if(nDlist%8 == 0)
+		Dlist = allocn(Dlist, nDlist*sizeof(char *),
+			8*sizeof(char *));
+	Dlist[nDlist++] = p;
+}
+
+void
+usage(void)
+{
+	print("usage: %ca [options] file.c...\n", thechar);
+	flagprint(1);
+	errorexit();
+}
 void
 main(int argc, char *argv[])
 {
 	char *p;
-	int c;
 
 	thechar = '8';
 	thestring = "386";
@@ -90,44 +105,24 @@ main(int argc, char *argv[])
 	cinit();
 	outfile = 0;
 	setinclude(".");
-	ARGBEGIN {
-	default:
-		c = ARGC();
-		if(c >= 0 && c < sizeof(debug))
-			debug[c] = 1;
-		break;
-
-	case 'o':
-		outfile = ARGF();
-		break;
-
-	case 'D':
-		p = ARGF();
-		if(p) {
-			if (nDlist%8 == 0)
-				Dlist = allocn(Dlist, nDlist*sizeof(char *), 
-					8*sizeof(char *));
-			Dlist[nDlist++] = p;
-		}
-		break;
-
-	case 'I':
-		p = ARGF();
-		setinclude(p);
-		break;
-
-	case 'S':
-		ctxt->debugasm++;
-		break;
-	} ARGEND
-	if(*argv == 0) {
-		print("usage: %ca [-options] file.s\n", thechar);
-		errorexit();
-	}
+	
+	flagfn1("D", "name[=value]: add #define", dodef);
+	flagfn1("I", "dir: add dir to include path", setinclude);
+	flagcount("S", "print assembly and machine code", &debug['S']);
+	flagcount("m", "debug preprocessor macros", &debug['m']);
+	flagstr("o", "file: set output file", &outfile);
+	flagstr("trimpath", "prefix: remove prefix from recorded source file paths", &ctxt->trimpath);
+
+	flagparse(&argc, &argv, usage);
+	ctxt->debugasm = debug['S'];
+
+	if(argc < 1)
+		usage();
 	if(argc > 1){
 		print("can't assemble multiple files\n");
 		errorexit();
 	}
+
 	if(assemble(argv[0]))
 		errorexit();
 	Bflush(&bstdout);
diff --git a/src/cmd/cc/lex.c b/src/cmd/cc/lex.c
index a8ece212f0..4248437643 100644
--- a/src/cmd/cc/lex.c
+++ b/src/cmd/cc/lex.c
@@ -195,6 +195,7 @@ main(int argc, char *argv[])
 	flagcount("q", "print Go definitions", &debug['q']);
 	flagcount("s", "print #define assembly offsets", &debug['s']);
 	flagcount("t", "debug code generation", &debug['t']);
+	flagstr("trimpath", "prefix: remove prefix from recorded source file paths", &ctxt->trimpath);
 	flagcount("w", "enable warnings", &debug['w']);
 	flagcount("v", "increase debug verbosity", &debug['v']);	
 	if(thechar == '6')
diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index f372581aae..7e28205656 100644
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -306,6 +306,7 @@ main(int argc, char *argv[])
 	flagcount("r", "debug generated wrappers", &debug['r']);
 	flagcount("race", "enable race detector", &flag_race);
 	flagcount("s", "warn about composite literals that can be simplified", &debug['s']);
+	flagstr("trimpath", "prefix: remove prefix from recorded source file paths", &ctxt->trimpath);
 	flagcount("u", "reject unsafe code", &safemode);
 	flagcount("v", "increase debug verbosity", &debug['v']);
 	flagcount("w", "debug type checking", &debug['w']);
diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index d7a1d21828..03300555de 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -1599,7 +1599,7 @@ func (gcToolchain) gc(b *builder, p *Package, archive, obj string, importArgs []
 		gcargs = append(gcargs, "-installsuffix", buildContext.InstallSuffix)
 	}
 
-	args := stringList(tool(archChar+"g"), "-o", ofile, buildGcflags, gcargs, "-D", p.localPrefix, importArgs)
+	args := stringList(tool(archChar+"g"), "-o", ofile, "-trimpath", b.work, buildGcflags, gcargs, "-D", p.localPrefix, importArgs)
 	if ofile == archive {
 		args = append(args, "-pack")
 	}
@@ -1613,7 +1613,7 @@ func (gcToolchain) gc(b *builder, p *Package, archive, obj string, importArgs []
 
 func (gcToolchain) asm(b *builder, p *Package, obj, ofile, sfile string) error {
 	sfile = mkAbs(p.Dir, sfile)
-	return b.run(p.Dir, p.ImportPath, nil, tool(archChar+"a"), "-I", obj, "-o", ofile, "-D", "GOOS_"+goos, "-D", "GOARCH_"+goarch, sfile)
+	return b.run(p.Dir, p.ImportPath, nil, tool(archChar+"a"), "-trimpath", b.work, "-I", obj, "-o", ofile, "-D", "GOOS_"+goos, "-D", "GOARCH_"+goarch, sfile)
 }
 
 func (gcToolchain) pkgpath(basedir string, p *Package) string {
@@ -1626,7 +1626,7 @@ func (gcToolchain) pack(b *builder, p *Package, objDir, afile string, ofiles []s
 	for _, f := range ofiles {
 		absOfiles = append(absOfiles, mkAbs(objDir, f))
 	}
-	cmd := "grcP"
+	cmd := "c"
 	absAfile := mkAbs(objDir, afile)
 	appending := false
 	if _, err := os.Stat(absAfile); err == nil {
@@ -1784,7 +1784,7 @@ func (gcToolchain) ld(b *builder, p *Package, out string, allactions []*action,
 func (gcToolchain) cc(b *builder, p *Package, objdir, ofile, cfile string) error {
 	inc := filepath.Join(goroot, "pkg", fmt.Sprintf("%s_%s", goos, goarch))
 	cfile = mkAbs(p.Dir, cfile)
-	args := stringList(tool(archChar+"c"), "-F", "-V", "-w", "-I", objdir, "-I", inc, "-o", ofile, buildCcflags, "-D", "GOOS_"+goos, "-D", "GOARCH_"+goarch, cfile)
+	args := stringList(tool(archChar+"c"), "-F", "-V", "-w", "-trimpath", b.work, "-I", objdir, "-I", inc, "-o", ofile, buildCcflags, "-D", "GOOS_"+goos, "-D", "GOARCH_"+goarch, cfile)
 	return b.run(p.Dir, p.ImportPath, nil, args)
 }
 
diff --git a/src/liblink/obj.c b/src/liblink/obj.c
index 856227fe83..53ae470354 100644
--- a/src/liblink/obj.c
+++ b/src/liblink/obj.c
@@ -87,6 +87,34 @@ linklinefmt(Link *ctxt, Fmt *fp)
 	return 0;
 }
 
+// Does s have t as a path prefix?
+// That is, does s == t or does s begin with t followed by a slash?
+// For portability, we allow ASCII case folding, so that haspathprefix("a/b/c", "A/B") is true.
+// Similarly, we allow slash folding, so that haspathprefix("a/b/c", "a\\b") is true.
+static int
+haspathprefix(char *s, char *t)
+{
+	int i, cs, ct;
+
+	if(t == nil)
+		return 0;
+	for(i=0; t[i]; i++) {
+		cs = s[i];
+		ct = t[i];
+		if('A' <= cs && cs <= 'Z')
+			cs += 'a' - 'A';
+		if('A' <= ct && ct <= 'Z')
+			ct += 'a' - 'A';
+		if(cs == '\\')
+			cs = '/';
+		if(ct == '\\')
+			ct = '/';
+		if(cs != ct)
+			return 0;
+	}
+	return s[i] == '\0' || s[i] == '/' || s[i] == '\\';
+}
+
 // This is a simplified copy of linklinefmt above.
 // It doesn't allow printing the full stack, and it returns the file name and line number separately.
 // TODO: Unify with linklinefmt somehow.
@@ -103,7 +131,7 @@ linkgetline(Link *ctxt, int32 line, LSym **f, int32 *l)
 	int32 lno, d, dlno;
 	int n;
 	Hist *h;
-	char buf[1024], *file;
+	char buf[1024], buf1[1024], *file;
 
 	lno = line;
 	n = 0;
@@ -159,6 +187,22 @@ linkgetline(Link *ctxt, int32 line, LSym **f, int32 *l)
 		snprint(buf, sizeof buf, "%s", file);
 	else
 		snprint(buf, sizeof buf, "%s/%s", ctxt->pathname, file);
+
+	// Remove leading ctxt->trimpath, or else rewrite $GOROOT to $GOROOT_FINAL.
+	if(haspathprefix(buf, ctxt->trimpath)) {
+		if(strlen(buf) == strlen(ctxt->trimpath))
+			strcpy(buf, "??");
+		else {
+			snprint(buf1, sizeof buf1, "%s", buf+strlen(ctxt->trimpath)+1);
+			if(buf1[0] == '\0')
+				strcpy(buf1, "??");
+			strcpy(buf, buf1);
+		}
+	} else if(ctxt->goroot_final != nil && haspathprefix(buf, ctxt->goroot)) {
+		snprint(buf1, sizeof buf1, "%s%s", ctxt->goroot_final, buf+strlen(ctxt->goroot));
+		strcpy(buf, buf1);
+	}
+
 	lno -= dlno;
 	*f = linklookup(ctxt, buf, HistVersion);
 	*l = lno;
diff --git a/src/liblink/sym.c b/src/liblink/sym.c
index 29fc036bcb..ff51b3df89 100644
--- a/src/liblink/sym.c
+++ b/src/liblink/sym.c
@@ -95,6 +95,10 @@ linknew(LinkArch *arch)
 	ctxt = emallocz(sizeof *ctxt);
 	ctxt->arch = arch;
 	ctxt->version = HistVersion;
+	ctxt->goroot = getgoroot();
+	ctxt->goroot_final = getenv("GOROOT_FINAL");
+	if(ctxt->goroot_final != nil && ctxt->goroot_final[0] == '\0')
+		ctxt->goroot_final = nil;
 
 	p = getgoarch();
 	if(strcmp(p, arch->name) != 0)
-- 
2.30.9