ack/lang/m2/comp/walk.c

759 lines
16 KiB
C

/* P A R S E T R E E W A L K E R */
/* Routines to walk through parts of the parse tree, and generate
code for these parts.
*/
#include "debug.h"
#include <em_arith.h>
#include <em_label.h>
#include <em_reg.h>
#include <em_code.h>
#include <assert.h>
#include "def.h"
#include "type.h"
#include "scope.h"
#include "main.h"
#include "LLlex.h"
#include "node.h"
#include "Lpars.h"
#include "desig.h"
#include "f_info.h"
#include "idf.h"
#include "chk_expr.h"
#include "walk.h"
#include "warning.h"
extern arith NewPtr();
extern arith NewInt();
extern int proclevel;
label text_label;
label data_label;
static struct type *func_type;
struct withdesig *WithDesigs;
struct node *Modules;
#define NO_EXIT_LABEL ((label) 0)
#define RETURN_LABEL ((label) 1)
STATIC
DoProfil()
{
static label filename_label = 0;
if (! options['L']) {
register label fn_label = filename_label;
if (!fn_label) {
filename_label = fn_label = ++data_label;
C_df_dlb(fn_label);
C_rom_scon(FileName, (arith) (strlen(FileName) + 1));
}
C_fil_dlb(fn_label, (arith) 0);
}
}
WalkModule(module)
register struct def *module;
{
/* Walk through a module, and all its local definitions.
Also generate code for its body.
This code is collected in an initialization routine.
*/
register struct scope *sc;
struct scopelist *savevis = CurrVis;
CurrVis = module->mod_vis;
sc = CurrentScope;
/* Walk through it's local definitions
*/
WalkDef(sc->sc_def);
/* Now, generate initialization code for this module.
First call initialization routines for modules defined within
this module.
*/
sc->sc_off = 0; /* no locals (yet) */
text_label = 1; /* label at end of initialization routine */
TmpOpen(sc); /* Initialize for temporaries */
C_pro_narg(sc->sc_name);
DoProfil();
if (module == Defined) {
/* Body of implementation or program module.
Call initialization routines of imported modules.
Also prevent recursive calls of this one.
*/
register struct node *nd = Modules;
if (state == IMPLEMENTATION) {
label l1 = ++data_label;
/* we don't actually prevent recursive calls,
but do nothing if called recursively
*/
C_df_dlb(l1);
C_bss_cst(word_size, (arith) 0, 1);
/* if this one is set to non-zero, the initialization
was already done.
*/
C_loe_dlb(l1, (arith) 0);
C_zne(RETURN_LABEL);
C_ine_dlb(l1, (arith) 0);
}
for (; nd; nd = nd->next) {
C_cal(nd->nd_IDF->id_text);
}
}
MkCalls(sc->sc_def);
proclevel++;
DO_DEBUG(options['X'], PrNode(module->mod_body, 0));
WalkNode(module->mod_body, NO_EXIT_LABEL);
C_df_ilb(RETURN_LABEL);
C_ret((arith) 0);
C_end(-sc->sc_off);
proclevel--;
TmpClose();
CurrVis = savevis;
}
WalkProcedure(procedure)
register struct def *procedure;
{
/* Walk through the definition of a procedure and all its
local definitions, checking and generating code.
*/
struct scopelist *savevis = CurrVis;
register struct scope *sc = procedure->prc_vis->sc_scope;
register struct type *tp;
register struct paramlist *param;
label func_res_label = 0;
arith StackAdjustment = 0;
arith retsav = 0;
arith func_res_size = 0;
proclevel++;
CurrVis = procedure->prc_vis;
/* Generate code for all local modules and procedures
*/
WalkDef(sc->sc_def);
/* Generate code for this procedure
*/
C_pro_narg(sc->sc_name);
DoProfil();
TmpOpen(sc);
func_type = tp = RemoveEqual(ResultType(procedure->df_type));
if (tp && IsConstructed(tp)) {
/* The result type of this procedure is constructed.
The actual procedure will return a pointer to a global
data area in which the function result is stored.
Notice that this does make the code non-reentrant.
Here, we create the data area for the function result.
*/
func_res_label = ++data_label;
C_df_dlb(func_res_label);
C_bss_cst(tp->tp_size, (arith) 0, 0);
}
if (tp) func_res_size = WA(tp->tp_size);
/* Generate calls to initialization routines of modules defined within
this procedure
*/
MkCalls(sc->sc_def);
/* Make sure that arguments of size < word_size are on a
fixed place.
Also make copies of conformant arrays when neccessary.
*/
for (param = ParamList(procedure->df_type);
param;
param = param->next) {
if (! IsVarParam(param)) {
tp = TypeOfParam(param);
if (! IsConformantArray(tp)) {
if (tp->tp_size < word_size) {
C_lol(param->par_def->var_off);
C_lal(param->par_def->var_off);
C_sti(tp->tp_size);
}
}
else {
/* Here, we have to make a copy of the
array. We must also remember how much
room is reserved for copies, because
we have to adjust the stack pointer before
a RET is done. This is even more complicated
when the procedure returns a value.
Then, the value must be saved (in retval),
the stack adjusted, the return value pushed
again, and then RET
*/
arith tmpvar = NewInt();
if (! StackAdjustment) {
/* First time we get here
*/
if (tp && !func_res_label) {
/* Some local space, only
needed if the value itself
is returned
*/
sc->sc_off -= func_res_size;
retsav = sc->sc_off;
}
StackAdjustment = NewInt();
C_loc((arith) 0);
C_stl(StackAdjustment);
}
/* First compute the size of the array */
C_lol(param->par_def->var_off +
pointer_size + word_size);
/* upper - lower */
C_inc(); /* gives number of elements */
C_loc(tp->arr_elem->tp_size);
C_mli(word_size);
C_loc(word_size - 1);
C_adi(word_size);
C_loc(word_size);
C_dvi(word_size);
/* size in words */
C_loc(word_size);
C_mli(word_size);
/* size in bytes */
C_stl(tmpvar);
C_lol(tmpvar);
C_lol(tmpvar);
C_lol(StackAdjustment);
C_adi(word_size);
C_stl(StackAdjustment);
/* remember stack adjustments */
C_ngi(word_size);
/* Assumption: stack grows
downwards!! ???
*/
C_ass(word_size);
/* adjusted stack pointer */
C_lol(param->par_def->var_off);
/* push source address */
C_lol(tmpvar); /* push size */
C_cal("_load"); /* copy */
C_asp(2 * word_size);
C_lor((arith) 1);
/* push new address of array
... downwards ... ???
*/
C_stl(param->par_def->var_off);
FreeInt(tmpvar);
}
}
}
text_label = 1; /* label at end of procedure */
DO_DEBUG(options['X'], PrNode(procedure->prc_body, 0));
WalkNode(procedure->prc_body, NO_EXIT_LABEL);
C_df_ilb(RETURN_LABEL); /* label at end */
tp = func_type;
if (func_res_label) {
/* Fill the data area reserved for the function result
with the result
*/
C_lae_dlb(func_res_label, (arith) 0);
C_sti(tp->tp_size);
if (StackAdjustment) {
/* Remove copies of conformant arrays
*/
C_lol(StackAdjustment);
C_ass(word_size);
}
C_lae_dlb(func_res_label, (arith) 0);
C_ret(pointer_size);
}
else if (tp) {
if (StackAdjustment) {
/* First save the function result in a safe place.
Then remove copies of conformant arrays,
and put function result back on the stack
*/
C_lal(retsav);
C_sti(func_res_size);
C_lol(StackAdjustment);
C_ass(word_size);
C_lal(retsav);
C_loi(func_res_size);
}
C_ret(func_res_size);
}
else {
if (StackAdjustment) {
C_lol(StackAdjustment);
C_ass(word_size);
}
C_ret((arith) 0);
}
if (StackAdjustment) FreeInt(StackAdjustment);
if (! options['n']) RegisterMessages(sc->sc_def);
C_end(-sc->sc_off);
TmpClose();
CurrVis = savevis;
proclevel--;
}
WalkDef(df)
register struct def *df;
{
/* Walk through a list of definitions
*/
for ( ; df; df = df->df_nextinscope) {
switch(df->df_kind) {
case D_MODULE:
WalkModule(df);
break;
case D_PROCEDURE:
WalkProcedure(df);
break;
case D_VARIABLE:
if (!proclevel) {
C_df_dnam(df->var_name);
C_bss_cst(
WA(df->df_type->tp_size),
(arith) 0, 0);
}
break;
default:
/* nothing */
;
}
}
}
MkCalls(df)
register struct def *df;
{
/* Generate calls to initialization routines of modules
*/
for ( ; df; df = df->df_nextinscope) {
if (df->df_kind == D_MODULE) {
C_lxl((arith) 0);
C_cal(df->mod_vis->sc_scope->sc_name);
C_asp(pointer_size);
}
}
}
WalkLink(nd, exit_label)
register struct node *nd;
label exit_label;
{
/* Walk node "nd", which is a link.
*/
while (nd && nd->nd_class == Link) { /* statement list */
WalkNode(nd->nd_left, exit_label);
nd = nd->nd_right;
}
WalkNode(nd, exit_label);
}
WalkCall(nd)
register struct node *nd;
{
assert(nd->nd_class == Call);
if (! options['L']) C_lin((arith) nd->nd_lineno);
if (ChkCall(nd)) {
if (nd->nd_type != 0) {
node_error(nd, "procedure call expected");
return;
}
CodeCall(nd);
}
}
WalkStat(nd, exit_label)
register struct node *nd;
label exit_label;
{
/* Walk through a statement, generating code for it.
*/
register struct node *left = nd->nd_left;
register struct node *right = nd->nd_right;
assert(nd->nd_class == Stat);
if (! options['L']) C_lin((arith) nd->nd_lineno);
switch(nd->nd_symb) {
case BECOMES:
DoAssign(nd, left, right);
break;
case IF:
{ label l1 = ++text_label, l3 = ++text_label;
ExpectBool(left, l3, l1);
assert(right->nd_symb == THEN);
C_df_ilb(l3);
WalkNode(right->nd_left, exit_label);
if (right->nd_right) { /* ELSE part */
label l2 = ++text_label;
C_bra(l2);
C_df_ilb(l1);
WalkNode(right->nd_right, exit_label);
C_df_ilb(l2);
}
else C_df_ilb(l1);
break;
}
case CASE:
CaseCode(nd, exit_label);
break;
case WHILE:
{ label loop = ++text_label,
exit = ++text_label,
dummy = ++text_label;
C_df_ilb(loop);
ExpectBool(left, dummy, exit);
C_df_ilb(dummy);
WalkNode(right, exit_label);
C_bra(loop);
C_df_ilb(exit);
break;
}
case REPEAT:
{ label loop = ++text_label, exit = ++text_label;
C_df_ilb(loop);
WalkNode(left, exit_label);
ExpectBool(right, exit, loop);
C_df_ilb(exit);
break;
}
case LOOP:
{ label loop = ++text_label, exit = ++text_label;
C_df_ilb(loop);
WalkNode(right, exit);
C_bra(loop);
C_df_ilb(exit);
break;
}
case FOR:
{
arith tmp = 0;
register struct node *fnd;
int good_forvar;
label l1 = ++text_label;
label l2 = ++text_label;
good_forvar = DoForInit(nd, left);
fnd = left->nd_right;
if (fnd->nd_class != Value) {
/* Upperbound not constant.
The expression may only be evaluated once,
so generate a temporary for it
*/
CodePExpr(fnd);
tmp = NewInt();
C_stl(tmp);
}
C_df_ilb(l1);
C_dup(int_size);
if (tmp) C_lol(tmp); else C_loc(fnd->nd_INT);
if (left->nd_INT > 0) {
C_bgt(l2);
}
else C_blt(l2);
if (good_forvar) {
RangeCheck(nd->nd_type, int_type);
CodeDStore(nd);
}
WalkNode(right, exit_label);
if (good_forvar) {
CodePExpr(nd);
C_loc(left->nd_INT);
C_adi(int_size);
C_bra(l1);
C_df_ilb(l2);
C_asp(int_size);
}
if (tmp) FreeInt(tmp);
}
break;
case WITH:
{
struct scopelist link;
struct withdesig wds;
struct desig ds;
if (! WalkDesignator(left, &ds)) break;
if (left->nd_type->tp_fund != T_RECORD) {
node_error(left, "record variable expected");
break;
}
wds.w_next = WithDesigs;
WithDesigs = &wds;
wds.w_scope = left->nd_type->rec_scope;
CodeAddress(&ds);
ds.dsg_kind = DSG_FIXED;
/* Create a designator structure for the temporary.
*/
ds.dsg_offset = NewPtr();
ds.dsg_name = 0;
CodeStore(&ds, pointer_size, pointer_align);
ds.dsg_kind = DSG_PFIXED;
/* the record is indirectly available */
wds.w_desig = ds;
link.sc_scope = wds.w_scope;
link.next = CurrVis;
CurrVis = &link;
WalkNode(right, exit_label);
CurrVis = link.next;
WithDesigs = wds.w_next;
FreePtr(ds.dsg_offset);
break;
}
case EXIT:
assert(exit_label != 0);
C_bra(exit_label);
break;
case RETURN:
if (right) {
if (! ChkExpression(right)) break;
/* The type of the return-expression must be
assignment compatible with the result type of the
function procedure (See Rep. 9.11).
*/
if (!TstAssCompat(func_type, right->nd_type)) {
node_error(right, "type incompatibility in RETURN statement");
break;
}
if (right->nd_type->tp_fund == T_STRING) {
arith strsize = WA(right->nd_type->tp_size);
C_zer(WA(func_type->tp_size) - strsize);
CodePExpr(right);
C_loi(strsize);
}
else CodePExpr(right);
}
C_bra(RETURN_LABEL);
break;
default:
crash("(WalkStat)");
}
}
extern int NodeCrash();
int (*WalkTable[])() = {
NodeCrash,
NodeCrash,
NodeCrash,
NodeCrash,
NodeCrash,
WalkCall,
NodeCrash,
NodeCrash,
NodeCrash,
NodeCrash,
WalkStat,
WalkLink,
NodeCrash
};
ExpectBool(nd, true_label, false_label)
register struct node *nd;
label true_label, false_label;
{
/* "nd" must indicate a boolean expression. Check this and
generate code to evaluate the expression.
*/
struct desig ds;
if (!ChkExpression(nd)) return;
if (nd->nd_type != bool_type && nd->nd_type != error_type) {
node_error(nd, "boolean expression expected");
}
ds = InitDesig;
CodeExpr(nd, &ds, true_label, false_label);
}
int
WalkExpr(nd)
register struct node *nd;
{
/* Check an expression and generate code for it
*/
if (! ChkExpression(nd)) return 0;
CodePExpr(nd);
return 1;
}
int
WalkDesignator(nd, ds)
struct node *nd;
struct desig *ds;
{
/* Check designator and generate code for it
*/
if (! ChkVariable(nd)) return 0;
*ds = InitDesig;
CodeDesig(nd, ds);
return 1;
}
DoForInit(nd, left)
register struct node *nd, *left;
{
register struct def *df;
nd->nd_left = nd->nd_right = 0;
nd->nd_class = Name;
nd->nd_symb = IDENT;
if (!( ChkVariable(nd) &
WalkExpr(left->nd_left) &
ChkExpression(left->nd_right))) return 0;
df = nd->nd_def;
if (df->df_kind == D_FIELD) {
node_error(nd,
"FOR-loop variable may not be a field of a record");
return 1;
}
if (!df->var_name && df->var_off >= 0) {
node_error(nd, "FOR-loop variable may not be a parameter");
return 1;
}
if (df->df_scope != CurrentScope) {
register struct scopelist *sc = CurrVis;
for (;;) {
if (!sc) {
node_error(nd,
"FOR-loop variable may not be imported");
return 1;
}
if (sc->sc_scope == df->df_scope) break;
sc = nextvisible(sc);
}
}
if (df->df_type->tp_size > word_size ||
!(df->df_type->tp_fund & T_DISCRETE)) {
node_error(nd, "illegal type of FOR loop variable");
return 1;
}
if (!TstCompat(df->df_type, left->nd_left->nd_type) ||
!TstCompat(df->df_type, left->nd_right->nd_type)) {
if (!TstAssCompat(df->df_type, left->nd_left->nd_type) ||
!TstAssCompat(df->df_type, left->nd_right->nd_type)) {
node_error(nd, "type incompatibility in FOR statement");
return 1;
}
node_warning(nd, W_OLDFASHIONED, "compatibility required in FOR statement");
}
return 1;
}
DoAssign(nd, left, right)
struct node *nd;
register struct node *left, *right;
{
/* May we do it in this order (expression first) ???
The reference manual sais nothing about it, but the book does:
it sais that the left hand side is evaluated first.
DAMN THE BOOK!
*/
struct desig dsr;
register struct type *rtp, *ltp;
if (! (ChkExpression(right) & ChkVariable(left))) return;
rtp = right->nd_type;
ltp = left->nd_type;
if (right->nd_symb == STRING) TryToString(right, ltp);
dsr = InitDesig;
if (! TstAssCompat(ltp, rtp)) {
node_error(nd, "type incompatibility in assignment");
return;
}
#define StackNeededFor(ds) ((ds)->dsg_kind == DSG_PLOADED \
|| (ds)->dsg_kind == DSG_INDEXED)
CodeExpr(right, &dsr, NO_LABEL, NO_LABEL);
if (complex(rtp)) {
if (StackNeededFor(&dsr)) CodeAddress(&dsr);
}
else {
CodeValue(&dsr, rtp->tp_size, rtp->tp_align);
CodeCoercion(rtp, ltp);
RangeCheck(ltp, rtp);
}
CodeMove(&dsr, left, rtp);
}
RegisterMessages(df)
register struct def *df;
{
register struct type *tp;
for (; df; df = df->df_nextinscope) {
if (df->df_kind == D_VARIABLE && !(df->df_flags & D_NOREG)) {
/* Examine type and size
*/
tp = BaseType(df->df_type);
if ((df->df_flags & D_VARPAR) ||
(tp->tp_fund & (T_POINTER|T_HIDDEN|T_EQUAL))) {
C_ms_reg(df->var_off, pointer_size,
reg_pointer, 0);
}
else if (tp->tp_fund & T_NUMERIC) {
C_ms_reg(df->var_off,
tp->tp_size,
tp->tp_fund == T_REAL ?
reg_float : reg_any,
0);
}
}
}
}