delete unused code and data from 6.outs.

cuts simple test binary by 7%.
would be more except for reflection.

R=r
DELTA=126  (117 added, 4 deleted, 5 changed)
OCL=23163
CL=23237

diff --git a/src/cmd/6l/asm.c b/src/cmd/6l/asm.c
index 68e7ec54cf52d33bf237286f848fc3088319f253..f1972f8200228bc3b707b8a3b9d20b1f6d51bc0c 100644 (file)
--- a/src/cmd/6l/asm.c
+++ b/src/cmd/6l/asm.c
@@ -708,8 +708,10 @@ datblk(int32 s, int32 n)
                                if(p->to.sym) {
                                        if(p->to.sym->type == SUNDEF)
                                                ckoff(p->to.sym, o);
-                                       if(p->to.sym->type == Sxxx)
+                                       if(p->to.sym->type == Sxxx) {
+                                               curtext = p;    // show useful name in diag's output
                                                diag("missing symbol %s", p->to.sym->name);
+                                       }
                                        o += p->to.sym->value;
                                        if(p->to.sym->type != STEXT && p->to.sym->type != SUNDEF)
                                                o += INITDAT;

diff --git a/src/cmd/6l/go.c b/src/cmd/6l/go.c
index 07a0f21d546ebc933ae4841bf5e11492484a3fa4..a1a515fb3e2cacdbc1db588bba0ac1c6dd168594 100644 (file)
--- a/src/cmd/6l/go.c
+++ b/src/cmd/6l/go.c
@@ -514,10 +514,107 @@ ignoreoptfuncs(void)
                if(p->to.sym != S && p->to.sym->type == SOPT) {
                        if(p->as != ACALL)
                                diag("bad use of optional function: %P", p);
-                       p->as = ANOP;
-                       p->from.type = D_NONE;
-                       p->to.type = D_NONE;
+                       nopout(p);
                }
        }
 }
 
+static void mark(Sym*);
+static int markdepth;
+
+static void
+markdata(Prog *p, Sym *s)
+{
+       markdepth++;
+       if(p != P && debug['v'] > 1)
+               Bprint(&bso, "%d markdata %s\n", markdepth, s->name);
+       for(; p != P; p=p->dlink)
+               if(p->to.sym)
+                       mark(p->to.sym);
+       markdepth--;
+}
+
+static void
+marktext(Prog *p)
+{
+       if(p == P)
+               return;
+       if(p->as != ATEXT) {
+               diag("marktext: %P", p);
+               return;
+       }
+       markdepth++;
+       if(debug['v'] > 1)
+               Bprint(&bso, "%d marktext %s\n", markdepth, p->from.sym->name);
+       for(p=p->link; p != P; p=p->link) {
+               if(p->as == ATEXT || p->as == ADATA || p->as == AGLOBL)
+                       break;
+               if(p->from.sym)
+                       mark(p->from.sym);
+               if(p->to.sym)
+                       mark(p->to.sym);
+       }
+       markdepth--;
+}
+
+static void
+mark(Sym *s)
+{
+       if(s == S || s->reachable)
+               return;
+       s->reachable = 1;
+       if(s->text)
+               marktext(s->text);
+       if(s->data)
+               markdata(s->data, s);
+}
+
+static void
+sweeplist(Prog **first, Prog **last)
+{
+       int reachable;
+       Prog *p, *q;
+
+       reachable = 1;
+       q = P;
+       for(p=*first; p != P; p=p->link) {
+               switch(p->as) {
+               case ATEXT:
+               case ADATA:
+               case AGLOBL:
+                       reachable = p->from.sym->reachable;
+                       if(!reachable) {
+                               if(debug['v'] > 1)
+                                       Bprint(&bso, "discard %s\n", p->from.sym->name);
+                               p->from.sym->type = Sxxx;
+                       }
+                       break;
+               }
+               if(reachable) {
+                       if(q == P)
+                               *first = p;
+                       else
+                               q->link = p;
+                       q = p;
+               }
+       }
+       if(q == P)
+               *first = P;
+       else
+               q->link = P;
+       *last = q;
+}
+
+void
+deadcode(void)
+{
+       if(debug['v'])
+               Bprint(&bso, "%5.2f deadcode\n", cputime());
+
+       mark(lookup(INITENTRY, 0));
+       mark(lookup("sys·morestack", 0));
+
+       sweeplist(&firstp, &lastp);
+       sweeplist(&datap, &edatap);
+}
+

diff --git a/src/cmd/6l/l.h b/src/cmd/6l/l.h
index 4a2c456f2d63d66a2ddf4207312914121a2e2fd1..6382203a5964cdac25d873c5855d0abbf2371a0d 100644 (file)
--- a/src/cmd/6l/l.h
+++ b/src/cmd/6l/l.h
@@ -88,6 +88,7 @@ struct        Prog
        Adr     to;
        Prog    *forwd;
        Prog*   link;
+       Prog*   dlink;
        Prog*   pcond;  /* work on this */
        vlong   pc;
        int32   line;
@@ -120,6 +121,7 @@ struct      Sym
        int32   sig;
        Sym*    link;
        Prog*   text;
+       Prog*   data;
 };
 struct Optab
 {
@@ -385,9 +387,9 @@ Prog*       copyp(Prog*);
 double cputime(void);
 void   datblk(int32, int32);
 void   ignoreoptfuncs(void);
-void   definetypestrings(void);
-void definetypesigs(void);
 void   deadcode(void);
+void   definetypestrings(void);
+void   definetypesigs(void);
 void   diag(char*, ...);
 void   dodata(void);
 void   doinit(void);
@@ -421,6 +423,7 @@ void        mkfwd(void);
 void*  mysbrk(uint32);
 Prog*  newdata(Sym*, int, int, int);
 Prog*  newtext(Prog*, Sym*);
+void   nopout(Prog*);
 void   nuxiinit(void);
 void   objfile(char*);
 int    opsize(Prog*);

diff --git a/src/cmd/6l/list.c b/src/cmd/6l/list.c
index 0d85d3817d6ca914a3ed094415106f8bec32c9f1..000c6fa3783f53a4ff01c8a157428522d68b70a4 100644 (file)
--- a/src/cmd/6l/list.c
+++ b/src/cmd/6l/list.c
@@ -50,6 +50,9 @@ Pconv(Fmt *fp)
        Prog *p;
 
        p = va_arg(fp->args, Prog*);
+       if(p == P)
+               return fmtstrcpy(fp, "<P>");
+
        bigP = p;
 
        snprint(str1, sizeof(str1), "(%ld)", p->line);
@@ -421,7 +424,7 @@ parsetextconst(vlong arg)
        textstksiz = arg & 0xffffffffLL;
        if(textstksiz & 0x80000000LL)
                textstksiz = -(-textstksiz & 0xffffffffLL);
-               
+
        textarg = (arg >> 32) & 0xffffffffLL;
        if(textarg & 0x80000000LL)
                textarg = 0;

diff --git a/src/cmd/6l/obj.c b/src/cmd/6l/obj.c
index d6af049d9ae73abbbd59536ba998ba4132a8abd8..076809aa2fb249ac4a0279aeb7b1868c55c033eb 100644 (file)
--- a/src/cmd/6l/obj.c
+++ b/src/cmd/6l/obj.c
@@ -369,9 +369,9 @@ main(int argc, char *argv[])
                objfile(a);
        }
        ignoreoptfuncs();
-       // TODO(rsc): remove unused code and data
        definetypestrings();
        definetypesigs();
+       deadcode();
 
        firstp = firstp->link;
        if(firstp == P)
@@ -1068,11 +1068,16 @@ loop:
                // If we've seen an AGLOBL that said this sym was DUPOK,
                // ignore any more ADATA we see, which must be
                // redefinitions.
-               if(p->from.sym != S && p->from.sym->dupok) {
+               s = p->from.sym;
+               if(s != S && s->dupok) {
                        if(debug['v'])
-                               Bprint(&bso, "skipping %s in %s: dupok", p->from.sym->name, pn);
+                               Bprint(&bso, "skipping %s in %s: dupok", s->name, pn);
                        goto loop;
                }
+               if(s != S) {
+                       p->dlink = s->data;
+                       s->data = p;
+               }
                if(edatap == P)
                        datap = p;
                else

diff --git a/src/cmd/6l/pass.c b/src/cmd/6l/pass.c
index 45617ac5617b888773e7f465f56374703d5bb656..6e0fd58966841c8c7e49422b9c58e6133f0ca37a 100644 (file)
--- a/src/cmd/6l/pass.c
+++ b/src/cmd/6l/pass.c
@@ -42,6 +42,7 @@ dodata(void)
                Bprint(&bso, "%5.2f dodata\n", cputime());
        Bflush(&bso);
        for(p = datap; p != P; p = p->link) {
+               curtext = p;    // for diag messages
                s = p->from.sym;
                if(p->as == ADYNT || p->as == AINIT)
                        s->value = dtype;
@@ -851,6 +852,8 @@ newdata(Sym *s, int o, int w, int t)
        p->from.sym = s;
        p->from.offset = o;
        p->to.type = D_CONST;
+       p->dlink = s->data;
+       s->data = p;
        return p;
 }