undo CL 11683043 / bb75d03e6ccb

Broke arm build.
R=dave

««« original CL description
cc: generate argument pointer maps for C functions.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/11683043
»»»

R=golang-dev
CC=golang-dev
https://golang.org/cl/11788043

src/cmd/cc/pgen.c

@@ -31,8 +31,6 @@
 #include "gc.h"
 #include "../../pkg/runtime/funcdata.h"
 
-static int32 pointermap(Sym *gcsym, int32 offset);
-
 int
 hasdotdotdot(void)
 {
@@ -103,22 +101,7 @@ codgen(Node *n, Node *nn)
 
 	p = gtext(n1->sym, stkoff);
 	sp = p;
-
+	
-	/*
-	 * generate funcdata symbol for this function.
-	 * data is filled in at the end of codgen().
-	 */
-	snprint(namebuf, sizeof namebuf, "gc·%d", ngcsym++);
-	gcsym = slookup(namebuf);
-	gcsym->class = CSTATIC;
-
-	memset(&nod, 0, sizeof nod);
-	nod.op = ONAME;
-	nod.sym = gcsym;
-	nod.class = CSTATIC;
-
-	gins(AFUNCDATA, nodconst(FUNCDATA_GC), &nod);
-
 	/*
 	 * isolate first argument
 	 */
@@ -156,6 +139,17 @@ codgen(Node *n, Node *nn)
 		maxargsafe = xround(maxargsafe, 8);
 	sp->to.offset += maxargsafe;
 	
+	snprint(namebuf, sizeof namebuf, "gc·%d", ngcsym++);
+	gcsym = slookup(namebuf);
+	gcsym->class = CSTATIC;
+
+	memset(&nod, 0, sizeof nod);
+	nod.op = ONAME;
+	nod.sym = gcsym;
+	nod.class = CSTATIC;
+
+	gins(AFUNCDATA, nodconst(FUNCDATA_GC), &nod);
+
 	// TODO(rsc): "stkoff" is not right. It does not account for
 	// the possibility of data stored in .safe variables.
 	// Unfortunately those move up and down just like
@@ -168,7 +162,8 @@ codgen(Node *n, Node *nn)
 	off = 0;
 	gextern(gcsym, nodconst(stkoff), off, 4); // locals
 	off += 4;
-	off = pointermap(gcsym, off); // nptrs and ptrs[...]
+	gextern(gcsym, nodconst(0), off, 4); // nptrs
+	off += 4;
 	gcsym->type = typ(0, T);
 	gcsym->type->width = off;
 }
@@ -638,105 +633,3 @@ bcomplex(Node *n, Node *c)
 	boolgen(n, 1, Z);
 	return 0;
 }
-
-// Makes a bitmap marking the the pointers in t.  t starts at the given byte
-// offset in the argument list.  The returned bitmap should be for pointer
-// indexes (relative to offset 0) between baseidx and baseidx+32.
-static int32
-pointermap_type(Type *t, int32 offset, int32 baseidx)
-{
-	Type *t1;
-	int32 idx;
-	int32 m;
-
-	switch(t->etype) {
-	case TCHAR:
-	case TUCHAR:
-	case TSHORT:
-	case TUSHORT:
-	case TINT:
-	case TUINT:
-	case TLONG:
-	case TULONG:
-	case TVLONG:
-	case TUVLONG:
-	case TFLOAT:
-	case TDOUBLE:
-		// non-pointer types
-		return 0;
-	case TIND:
-	case TARRAY: // unlike Go, C passes arrays by reference
-		// pointer types
-		if((offset + t->offset) % ewidth[TIND] != 0)
-			yyerror("unaligned pointer");
-		idx = (offset + t->offset) / ewidth[TIND];
-		if(idx >= baseidx && idx < baseidx + 32)
-			return 1 << (idx - baseidx);
-		return 0;
-	case TSTRUCT:
-		// build map recursively
-		m = 0;
-		for(t1=t->link; t1; t1=t1->down)
-			m |= pointermap_type(t1, offset, baseidx);
-		return m;
-	case TUNION:
-		// We require that all elements of the union have the same pointer map.
-		m = pointermap_type(t->link, offset, baseidx);
-		for(t1=t->link->down; t1; t1=t1->down) {
-			if(pointermap_type(t1, offset, baseidx) != m)
-				yyerror("invalid union in argument list - pointer maps differ");
-		}
-		return m;
-	default:
-		yyerror("can't handle arg type %s\n", tnames[t->etype]);
-		return 0;
-	}
-}
-
-// Compute a bit vector to describe the pointer containing locations
-// in the argument list.  Adds the data to gcsym and returns the offset
-// of end of the bit vector.
-static int32
-pointermap(Sym *gcsym, int32 off)
-{
-	int32 nptrs;
-	int32 i;
-	int32 s;     // offset in argument list (in bytes)
-	int32 m;     // current ptrs[i/32]
-	Type *t;
-
-	if(hasdotdotdot()) {
-		// give up for C vararg functions.
-		// TODO: maybe make a map just for the args we do know?
-		gextern(gcsym, nodconst(0), off, 4); // nptrs=0
-		return off + 4;
-	}
-	nptrs = (argsize() + ewidth[TIND] - 1) / ewidth[TIND];
-	gextern(gcsym, nodconst(nptrs), off, 4);
-	off += 4;
-
-	for(i = 0; i < nptrs; i += 32) {
-		// generate mask for ptrs at offsets i ... i+31
-		m = 0;
-		s = align(0, thisfn->link, Aarg0, nil);
-		if(s > 0 && i == 0) {
-			// C Calling convention returns structs by copying
-			// them to a location pointed to by a hidden first
-			// argument.  This first argument is a pointer.
-			if(s != ewidth[TIND])
-				yyerror("passbyptr arg not the right size");
-			m = 1;
-		}
-		for(t=thisfn->down; t!=T; t=t->down) {
-			if(t->etype == TVOID)
-				continue;
-			s = align(s, t, Aarg1, nil);
-			m |= pointermap_type(t, s, i);
-			s = align(s, t, Aarg2, nil);
-		}
-		gextern(gcsym, nodconst(m), off, 4);
-		off += 4;
-	}
-	return off;
-	// TODO: needs a test for nptrs>32
-}