ld: defend against some broken object files

Fixes #1698.
Fixes #1699.

R=ken2
CC=golang-dev
https://golang.org/cl/4419041

src/cmd/5l/obj.c

@@ -581,7 +581,7 @@ loop:
 			diag("multiple initialization for %s: in both %s and %s", s->name, s->file, pn);
 			errorexit();
 		}
-		savedata(s, p);
+		savedata(s, p, pn);
 		unmal(p, sizeof *p);
 		break;
 

src/cmd/6l/obj.c

@@ -357,6 +357,15 @@ zaddr(char *pn, Biobuf *f, Adr *a, Sym *h[])
 		}
 	}
 	
+	switch(t) {
+	case D_FILE:
+	case D_FILE1:
+	case D_AUTO:
+	case D_PARAM:
+		if(s == S)
+			mangle(pn);
+	}
+
 	u = mal(sizeof(*u));
 	u->link = curauto;
 	curauto = u;
@@ -559,7 +568,7 @@ loop:
 			diag("multiple initialization for %s: in both %s and %s", s->name, s->file, pn);
 			errorexit();
 		}
-		savedata(s, p);
+		savedata(s, p, pn);
 		unmal(p, sizeof *p);
 		goto loop;
 

src/cmd/8l/obj.c

@@ -600,7 +600,7 @@ loop:
 			diag("multiple initialization for %s: in both %s and %s", s->name, s->file, pn);
 			errorexit();
 		}
-		savedata(s, p);
+		savedata(s, p, pn);
 		unmal(p, sizeof *p);
 		goto loop;
 

src/cmd/ld/data.c

@@ -312,7 +312,7 @@ symgrow(Sym *s, int32 siz)
 }
 
 void
-savedata(Sym *s, Prog *p)
+savedata(Sym *s, Prog *p, char *pn)
 {
 	int32 off, siz, i, fl;
 	uchar *cast;
@@ -321,6 +321,8 @@ savedata(Sym *s, Prog *p)
 
 	off = p->from.offset;
 	siz = p->datasize;
+	if(off < 0 || siz < 0 || off >= 1<<30 || siz >= 100)
+		mangle(pn);
 	symgrow(s, off+siz);
 
 	switch(p->to.type) {

src/cmd/ld/lib.c

@@ -438,7 +438,7 @@ ldobj(Biobuf *f, char *pkg, int64 len, char *pn, int whence)
 		return;
 	}
 	t = smprint("%s %s %s", getgoos(), thestring, getgoversion());
-	if(strcmp(line+10, t) != 0) {
+	if(strcmp(line+10, t) != 0 && !debug['f']) {
 		diag("%s: object is [%s] expected [%s]", pn, line+10, t);
 		free(t);
 		return;

src/cmd/ld/lib.h

@@ -173,7 +173,7 @@ void	datblk(int32, int32);
 Sym*	datsort(Sym*);
 void	reloc(void);
 void	relocsym(Sym*);
-void	savedata(Sym*, Prog*);
+void	savedata(Sym*, Prog*, char*);
 void	symgrow(Sym*, int32);
 vlong	addstring(Sym*, char*);
 vlong	adduint32(Sym*, uint32);