cmd/gc: implement -pack flag

The -pack flag causes 5g, 6g, 8g to write a Go archive directly,
instead of requiring the use of 'go tool pack' to convert the .5/.6/.8
to .a format.

Writing directly avoids the copy and also avoids having the
export data stored twice in the archive (once in __.PKGDEF,
once in .5/.6/.8).

A separate CL will enable the use of this flag by cmd/go.

Other build systems that do not know about -pack will be unaffected.

The changes to cmd/ld handle a minor simplification to the format:
an unused section is removed.

R=iant, r
CC=golang-dev
https://golang.org/cl/42880043

diff --git a/src/cmd/gc/export.c b/src/cmd/gc/export.c
index 31bcdf8e779b1db4e0e6b43da3e8383e9dc71956..da5984cebf864958bd29c4b0acfe78b8b06c8000 100644 (file)
--- a/src/cmd/gc/export.c
+++ b/src/cmd/gc/export.c
@@ -354,7 +354,7 @@ dumpexport(void)
 
        lno = lineno;
 
-       Bprint(bout, "\n$$  // exports\n    package %s", localpkg->name);
+       Bprint(bout, "\n$$\npackage %s", localpkg->name);
        if(safemode)
                Bprint(bout, " safe");
        Bprint(bout, "\n");
@@ -369,8 +369,7 @@ dumpexport(void)
                dumpsym(l->n->sym);
        }
 
-       Bprint(bout, "\n$$  // local types\n\n$$\n");   // 6l expects this. (see ld/go.c)
-
+       Bprint(bout, "\n$$\n");
        lineno = lno;
 }
 

diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 081220db5ae044449338d1d53a60e244208ea650..3840c9adf97de849546206db5dc55c9de23c6676 100644 (file)
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -977,6 +977,7 @@ EXTERN      Link*   ctxt;
 EXTERN int     nointerface;
 EXTERN int     fieldtrack_enabled;
 EXTERN int     precisestack_enabled;
+EXTERN int     writearchive;
 
 EXTERN Biobuf  bstdout;
 

diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index 0d1fccb10da141961035073785ad677f7b9a1ac5..c2116b4c6f51d6e9180a4c826db6e3ed8c1f5856 100644 (file)
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -267,6 +267,7 @@ main(int argc, char *argv[])
        flagcount("m", "print optimization decisions", &debug['m']);
        flagstr("o", "obj: set output file", &outfile);
        flagstr("p", "path: set expected package import path", &myimportpath);
+       flagcount("pack", "write package file instead of object file", &writearchive);
        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']);
@@ -518,12 +519,13 @@ skiptopkgdef(Biobuf *b)
                return 0;
        if(memcmp(p, "!<arch>\n", 8) != 0)
                return 0;
-       /* symbol table is first; skip it */
+       /* symbol table may be first; skip it */
        sz = arsize(b, "__.GOSYMDEF");
-       if(sz < 0)
-               return 0;
-       Bseek(b, sz, 1);
-       /* package export block is second */
+       if(sz >= 0)
+               Bseek(b, sz, 1);
+       else
+               Bseek(b, 8, 0);
+       /* package export block is next */
        sz = arsize(b, "__.PKGDEF");
        if(sz <= 0)
                return 0;

diff --git a/src/cmd/gc/obj.c b/src/cmd/gc/obj.c
index 37d3a0326092e3edcaa5bfa897bc34960fa9d094..3b9a97320f845b7d1123fab615a9c7559ff41d05 100644 (file)
--- a/src/cmd/gc/obj.c
+++ b/src/cmd/gc/obj.c
@@ -12,10 +12,25 @@
 
 static void    dumpglobls(void);
 
+enum
+{
+       ArhdrSize = 60
+};
+
+static void
+formathdr(char *arhdr, char *name, vlong size)
+{
+       snprint(arhdr, ArhdrSize, "%-16s%-12d%-6d%-6d%-8o%-10d`",
+               name, 0, 0, 0, 0644, size);
+       arhdr[ArhdrSize-1] = '\n'; // overwrite \0 written by snprint
+}
+
 void
 dumpobj(void)
 {
        NodeList *externs, *tmp;
+       char arhdr[ArhdrSize];
+       vlong startobj, size;
        Sym *zero;
 
        bout = Bopen(outfile, OWRITE);
@@ -25,10 +40,33 @@ dumpobj(void)
                errorexit();
        }
 
+       startobj = 0;
+       if(writearchive) {
+               Bwrite(bout, "!<arch>\n", 8);
+               memset(arhdr, 0, sizeof arhdr);
+               Bwrite(bout, arhdr, sizeof arhdr);
+               startobj = Boffset(bout);
+       }
        Bprint(bout, "go object %s %s %s %s\n", getgoos(), thestring, getgoversion(), expstring());
-       Bprint(bout, "  exports automatically generated from\n");
-       Bprint(bout, "  %s in package \"%s\"\n", curio.infile, localpkg->name);
        dumpexport();
+       
+       if(writearchive) {
+               Bflush(bout);
+               size = Boffset(bout) - startobj;
+               if(size&1)
+                       Bputc(bout, 0);
+               Bseek(bout, startobj - ArhdrSize, 0);
+               formathdr(arhdr, "__.PKGDEF", size);
+               Bwrite(bout, arhdr, ArhdrSize);
+               Bflush(bout);
+
+               Bseek(bout, startobj + size + (size&1), 0);
+               memset(arhdr, 0, ArhdrSize);
+               Bwrite(bout, arhdr, ArhdrSize);
+               startobj = Boffset(bout);
+               Bprint(bout, "go object %s %s %s %s\n", getgoos(), thestring, getgoversion(), expstring());
+       }
+
        Bprint(bout, "\n!\n");
 
        externs = nil;
@@ -51,6 +89,16 @@ dumpobj(void)
        dumpdata();
        linkwriteobj(ctxt, bout);
 
+       if(writearchive) {
+               Bflush(bout);
+               size = Boffset(bout) - startobj;
+               if(size&1)
+                       Bputc(bout, 0);
+               Bseek(bout, startobj - ArhdrSize, 0);
+               snprint(namebuf, sizeof namebuf, "_go_.%c", thechar);
+               formathdr(arhdr, namebuf, size);
+               Bwrite(bout, arhdr, ArhdrSize);
+       }
        Bterm(bout);
 }
 

diff --git a/src/cmd/ld/go.c b/src/cmd/ld/go.c
index 900ecb0ae90c5f6a102e8079bb040b27621527a6..a5a0fa5433172994529c8aed2b56efdd0110bd6d 100644 (file)
--- a/src/cmd/ld/go.c
+++ b/src/cmd/ld/go.c
@@ -151,28 +151,11 @@ ldpkg(Biobuf *f, char *pkg, int64 len, char *filename, int whence)
                }
                loadpkgdata(filename, pkg, p0, p1 - p0);
        }
-
-       // The __.PKGDEF archive summary has no local types.
+       
+       // __.PKGDEF has no cgo section - those are in the C compiler-generated object files.
        if(whence == Pkgdef)
                return;
 
-       // local types begin where exports end.
-       // skip rest of line after $$ we found above
-       p0 = p1 + 3;
-       while(*p0 != '\n' && *p0 != '\0')
-               p0++;
-
-       // local types end at next \n$$.
-       p1 = strstr(p0, "\n$$");
-       if(p1 == nil) {
-               fprint(2, "%s: cannot find end of local types in %s\n", argv0, filename);
-               if(debug['u'])
-                       errorexit();
-               return;
-       }
-
-       loadpkgdata(filename, pkg, p0, p1 - p0);
-
        // look for cgo section
        p0 = strstr(p1, "\n$$  // cgo");
        if(p0 != nil) {

diff --git a/src/cmd/ld/lib.c b/src/cmd/ld/lib.c
index 76a3a1393a84899c1f69ff6f56025cde412e8ef1..f4ac30a571ca854b129b08d0db911c295b184b09 100644 (file)
--- a/src/cmd/ld/lib.c
+++ b/src/cmd/ld/lib.c
@@ -327,25 +327,22 @@ objfile(char *file, char *pkg)
                return;
        }
        
-       /* skip over __.GOSYMDEF */
+       /* skip over optional __.GOSYMDEF and process __.PKGDEF */
        off = Boffset(f);
        if((l = nextar(f, off, &arhdr)) <= 0) {
                diag("%s: short read on archive file symbol header", file);
                goto out;
        }
-       if(strncmp(arhdr.name, symname, strlen(symname))) {
-               diag("%s: first entry not symbol header", file);
-               goto out;
-       }
-       off += l;
-       
-       /* skip over (or process) __.PKGDEF */
-       if((l = nextar(f, off, &arhdr)) <= 0) {
-               diag("%s: short read on archive file symbol header", file);
-               goto out;
+       if(strncmp(arhdr.name, symname, strlen(symname)) == 0) {
+               off += l;
+               if((l = nextar(f, off, &arhdr)) <= 0) {
+                       diag("%s: short read on archive file symbol header", file);
+                       goto out;
+               }
        }
+
        if(strncmp(arhdr.name, pkgname, strlen(pkgname))) {
-               diag("%s: second entry not package header", file);
+               diag("%s: cannot find package header", file);
                goto out;
        }
        off += l;