cmd/5g, cmd/5l, cmd/6l, cmd/8l, cmd/gc, cmd/ld, runtime: accurate args and locals information

Previously, the func structure contained an inaccurate value for
the args member and a 0 value for the locals member.

This change populates the func structure with args and locals
values computed by the compiler.  The number of args was
already available in the ATEXT instruction.  The number of
locals is now passed through in the new ALOCALS instruction.

This change also switches the unit of args and locals to be
bytes, just like the frame member, instead of 32-bit words.

R=golang-dev, bradfitz, cshapiro, dave, rsc
CC=golang-dev
https://golang.org/cl/7399045

src/cmd/5g/peep.c

@@ -1189,6 +1189,9 @@ copyu(Prog *p, Adr *v, Adr *s)
 			if(v->reg == (uchar)REGARG)
 				return 3;
 		return 0;
+
+	case ALOCALS:	/* funny */
+		return 0;
 	}
 }
 

src/cmd/5l/5.out.h

@@ -197,6 +197,7 @@ enum	as
 	AMULAWB,
 	
 	AUSEFIELD,
+	ALOCALS,
 
 	ALAST,
 };

src/cmd/5l/l.h

@@ -147,6 +147,8 @@ struct	Sym
 	int32	size;
 	int32	align;	// if non-zero, required alignment in bytes
 	int32	elfsym;
+	int32	locals;	// size of stack frame locals area
+	int32	args;	// size of stack frame incoming arguments area
 	uchar	special;
 	uchar	fnptr;	// used as fn ptr
 	uchar	stkcheck;

src/cmd/5l/obj.c

@@ -573,6 +573,11 @@ loop:
 		pc++;
 		break;
 
+	case ALOCALS:
+		cursym->locals = p->to.offset;
+		pc++;
+		break;
+
 	case ATEXT:
 		if(cursym != nil && cursym->text) {
 			histtoauto();
@@ -610,6 +615,7 @@ loop:
 		s->type = STEXT;
 		s->text = p;
 		s->value = pc;
+		s->args = p->to.offset2;
 		lastp = p;
 		p->pc = pc;
 		pc++;

src/cmd/5l/span.c

@@ -830,6 +830,7 @@ buildop(void)
 		case ARFE:
 		case ATEXT:
 		case AUSEFIELD:
+		case ALOCALS:
 		case ACASE:
 		case ABCASE:
 			break;

src/cmd/6l/6.out.h

@@ -758,6 +758,7 @@ enum	as
 	APSHUFD,
 	
 	AUSEFIELD,
+	ALOCALS,
 
 	ALAST
 };

src/cmd/6l/l.h

@@ -154,6 +154,8 @@ struct	Sym
 	int32	got;
 	int32	align;	// if non-zero, required alignment in bytes
 	int32	elfsym;
+	int32	locals;	// size of stack frame locals area
+	int32	args;	// size of stack frame incoming arguments area
 	Sym*	hash;	// in hash table
 	Sym*	allsym;	// in all symbol list
 	Sym*	next;	// in text or data list

src/cmd/6l/obj.c

@@ -586,6 +586,11 @@ loop:
 		pc++;
 		goto loop;
 
+	case ALOCALS:
+		cursym->locals = p->to.offset;
+		pc++;
+		goto loop;
+
 	case ATEXT:
 		s = p->from.sym;
 		if(s->text != nil) {
@@ -629,6 +634,7 @@ loop:
 		}
 		s->type = STEXT;
 		s->value = pc;
+		s->args = p->to.offset >> 32;
 		lastp = p;
 		p->pc = pc++;
 		goto loop;

src/cmd/6l/optab.c

@@ -1316,6 +1316,7 @@ Optab optab[] =
 	{ APSHUFD,	yaes2,	Pq,	0x70,(0) },
 
 	{ AUSEFIELD,	ynop,	Px, 0,0 },
+	{ ALOCALS },
 
 	{ AEND },
 	0

src/cmd/8l/8.out.h

@@ -568,6 +568,7 @@ enum	as
 	AXORPS,
 	
 	AUSEFIELD,
+	ALOCALS,
 
 	ALAST
 };

src/cmd/8l/l.h

@@ -138,6 +138,8 @@ struct	Sym
 	int32	got;
 	int32	align;	// if non-zero, required alignment in bytes
 	int32	elfsym;
+	int32	locals;	// size of stack frame locals area
+	int32	args;	// size of stack frame incoming arguments area
 	Sym*	hash;	// in hash table
 	Sym*	allsym;	// in all symbol list
 	Sym*	next;	// in text or data list

src/cmd/8l/obj.c

@@ -595,6 +595,11 @@ loop:
 		pc++;
 		goto loop;
 
+	case ALOCALS:
+		cursym->locals = p->to.offset;
+		pc++;
+		goto loop;
+
 	case ATEXT:
 		s = p->from.sym;
 		if(s->text != nil) {
@@ -633,6 +638,7 @@ loop:
 		}
 		s->type = STEXT;
 		s->value = pc;
+		s->args = p->to.offset2;
 		lastp = p;
 		p->pc = pc++;
 		goto loop;

src/cmd/8l/optab.c

@@ -961,6 +961,7 @@ Optab optab[] =
 	{ AXORPS,	yxm,	Pm, 0x57 },
 
 	{ AUSEFIELD,	ynop,	Px, 0,0 },
+	{ ALOCALS },
 
 	0
 };

src/cmd/gc/pgen.c

@@ -14,7 +14,7 @@ compile(Node *fn)
 {
 	Plist *pl;
 	Node nod1, *n;
-	Prog *ptxt;
+	Prog *plocals, *ptxt;
 	int32 lno;
 	Type *t;
 	Iter save;
@@ -87,6 +87,8 @@ compile(Node *fn)
 
 	ginit();
 
+	plocals = gins(ALOCALS, N, N);
+
 	for(t=curfn->paramfld; t; t=t->down)
 		gtrack(tracksym(t->type));
 
@@ -132,6 +134,9 @@ compile(Node *fn)
 
 	oldstksize = stksize;
 	allocauto(ptxt);
+
+	plocals->to.offset = stksize;
+
 	if(0)
 		print("allocauto: %lld to %lld\n", oldstksize, (vlong)stksize);
 

src/cmd/ld/lib.c

@@ -1626,8 +1626,10 @@ genasmsym(void (*put)(Sym*, char*, int, vlong, vlong, int, Sym*))
 
 		put(s, s->name, 'T', s->value, s->size, s->version, s->gotype);
 
-		/* frame, auto and param after */
+		/* frame, locals, args, auto and param after */
 		put(nil, ".frame", 'm', s->text->to.offset+PtrSize, 0, 0, 0);
+		put(nil, ".locals", 'm', s->locals, 0, 0, 0);
+		put(nil, ".args", 'm', s->args, 0, 0, 0);
 
 		for(a=s->autom; a; a=a->link)
 			if(a->type == D_AUTO)

src/pkg/runtime/extern.go

@@ -42,8 +42,8 @@ type Func struct { // Keep in sync with runtime.h:struct Func
 	pc0    uintptr // starting pc, ln for table
 	ln0    int32
 	frame  int32 // stack frame size
-	args   int32 // number of 32-bit in/out args
-	locals int32 // number of 32-bit locals
+	args   int32 // in/out args size
+	locals int32 // locals size
 }
 
 // FuncForPC returns a *Func describing the function that contains the

src/pkg/runtime/runtime.h

@@ -353,8 +353,8 @@ struct	Func
 	uintptr	pc0;	// starting pc, ln for table
 	int32	ln0;
 	int32	frame;	// stack frame size
-	int32	args;	// number of 32-bit in/out args
-	int32	locals;	// number of 32-bit locals
+	int32	args;	// in/out args size
+	int32	locals;	// locals size
 };
 
 // layout of Itab known to compilers

src/pkg/runtime/symtab.c

@@ -124,17 +124,17 @@ dofunc(Sym *sym)
 			f->frame = -sizeof(uintptr);
 		break;
 	case 'm':
-		if(nfunc > 0 && func != nil)
-			func[nfunc-1].frame += sym->value;
+		if(nfunc <= 0 || func == nil)
 			break;
-	case 'p':
-		if(nfunc > 0 && func != nil) {
-			f = &func[nfunc-1];
-			// args counts 32-bit words.
-			// sym->value is the arg's offset.
-			// don't know width of this arg, so assume it is 64 bits.
-			if(f->args < sym->value/4 + 2)
-				f->args = sym->value/4 + 2;
+		if(runtime·strcmp(sym->name, (byte*)".frame") == 0)
+			func[nfunc-1].frame = sym->value;
+		else if(runtime·strcmp(sym->name, (byte*)".locals") == 0)
+			func[nfunc-1].locals = sym->value;
+		else if(runtime·strcmp(sym->name, (byte*)".args") == 0)
+			func[nfunc-1].args = sym->value;
+		else {
+			runtime·printf("invalid 'm' symbol named '%s'\n", sym->name);
+			runtime·throw("mangled symbol table");
 		}
 		break;
 	case 'f':

src/pkg/runtime/traceback_arm.c

@@ -128,7 +128,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
 				if(m->throwing && gp == m->curg)
 					runtime·printf("[fp=%p] ", fp);
 				runtime·printf("%S(", f->name);
-				for(i = 0; i < f->args; i++) {
+				for(i = 0; i < f->args/sizeof(uintptr); i++) {
 					if(i != 0)
 						runtime·prints(", ");
 					runtime·printhex(((uintptr*)fp)[1+i]);

src/pkg/runtime/traceback_x86.c

@@ -130,7 +130,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
 				if(m->throwing && gp == m->curg)
 					runtime·printf("[fp=%p] ", fp);
 				runtime·printf("%S(", f->name);
-				for(i = 0; i < f->args; i++) {
+				for(i = 0; i < f->args/sizeof(uintptr); i++) {
 					if(i != 0)
 						runtime·prints(", ");
 					runtime·printhex(((uintptr*)fp)[i]);