ld: allow relocations pointing at ELF .bss symbols

R=r, r2
CC=golang-dev
https://golang.org/cl/3710042

diff --git a/src/cmd/ld/ldelf.c b/src/cmd/ld/ldelf.c
index f3dd8636b67ad98b3a05fd0b014e6671f93a421b..ccf6a412f7b5948c86444c31c87a41963a273b88 100644 (file)
--- a/src/cmd/ld/ldelf.c
+++ b/src/cmd/ld/ldelf.c
@@ -322,7 +322,7 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
        uchar *p, *dp;
        ElfHdrBytes *hdr;
        ElfObj *obj;
-       ElfSect *sect, *rsect, *text, *data, *bss, *rodata;
+       ElfSect *sect, *rsect;
        ElfSym sym;
        Endian *e;
        Reloc *r, *rp;
@@ -506,23 +506,13 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
        // they are not as small as the section lists, but we'll need
        // the memory anyway for the symbol images, so we might
        // as well use one large chunk.
-       text = section(obj, ".text");
-       if(text && map(obj, text) < 0)
-               goto bad;
-       data = section(obj, ".data");
-       if(data && map(obj, data) < 0)
-               goto bad;
-       bss = section(obj, ".bss");
-       rodata = section(obj, ".rodata");
-       if(rodata && map(obj, rodata) < 0)
-               goto bad;
        
        // create symbols for mapped sections
        for(i=0; i<obj->nsect; i++) {
                sect = &obj->sect[i];
-               if(sect->type != ElfSectProgbits || !(sect->flags&ElfSectFlagAlloc))
+               if((sect->type != ElfSectProgbits && sect->type != ElfSectNobits) || !(sect->flags&ElfSectFlagAlloc))
                        continue;
-               if(map(obj, sect) < 0)
+               if(sect->type != ElfSectNobits && map(obj, sect) < 0)
                        goto bad;
                
                name = smprint("%s(%s)", pn, sect->name);
@@ -542,8 +532,10 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
                        s->type = STEXT;
                        break;
                }
-               s->p = sect->base;
-               s->np = sect->size;
+               if(sect->type == ElfSectProgbits) {
+                       s->p = sect->base;
+                       s->np = sect->size;
+               }
                s->size = sect->size;
                if(s->type == STEXT) {
                        if(etextp)
@@ -598,7 +590,8 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
                        if(readsym(obj, info>>32, &sym) < 0)
                                goto bad;
                        if(sym.sym == nil) {
-                               werrstr("reloc of invalid sym %s shndx=%d type=%d", sym.name, sym.shndx, sym.type);
+                               werrstr("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d",
+                                       sect->sym->name, j, (int)(info>>32), sym.name, sym.shndx, sym.type);
                                goto bad;
                        }
                        rp->sym = sym.sym;