ack/lang/cem/cemcom/code.c

583 lines
14 KiB
C

/* $Header$ */
/* C O D E - G E N E R A T I N G R O U T I N E S */
#include <em.h>
#include "botch_free.h"
#include <alloc.h>
#include "nofloat.h"
#include "dataflow.h"
#include "use_tmp.h"
#include "arith.h"
#include "type.h"
#include "idf.h"
#include "label.h"
#include "code.h"
#include "stmt.h"
#include "def.h"
#include "expr.h"
#include "sizes.h"
#include "stack.h"
#include "level.h"
#include "decspecs.h"
#include "declar.h"
#include "Lpars.h"
#include "mes.h"
#include "LLlex.h"
#include "specials.h"
#include "atw.h"
#include "assert.h"
label lab_count = 1;
label datlab_count = 1;
#ifndef NOFLOAT
int fp_used;
#endif NOFLOAT
extern char options[];
char *symbol2str();
init_code(dst_file)
char *dst_file;
{
/* init_code() initialises the output file on which the
compact EM code is written
*/
C_init(word_size, pointer_size); /* initialise EM module */
if (C_open(dst_file) == 0)
fatal("cannot write to %s\n", dst_file);
#ifdef USE_TMP
if (options['N'])
#endif USE_TMP
famous_first_words();
}
famous_first_words()
{
C_magic();
C_ms_emx(word_size, pointer_size);
}
static struct string_cst *str_list = 0;
code_string(val, len, dlb)
char *val;
int len;
label dlb;
{
register struct string_cst *sc = new_string_cst();
C_ina_dlb(dlb);
sc->next = str_list;
str_list = sc;
sc->sc_value = val;
sc->sc_len = len;
sc->sc_dlb = dlb;
}
def_strings(sc)
register struct string_cst *sc;
{
if (sc) {
def_strings(sc->next);
C_df_dlb(sc->sc_dlb);
str_cst(sc->sc_value, sc->sc_len);
free_string_cst(sc);
}
}
end_code()
{
/* end_code() performs the actions to be taken when closing
the output stream.
*/
def_strings(str_list);
str_list = 0;
C_ms_src((int)(LineNumber - 2), FileName);
C_close();
}
#ifdef USE_TMP
prepend_scopes(dst_file)
char *dst_file;
{
/* prepend_scopes() runs down the list of global idf's
and generates those exa's, exp's, ina's and inp's
that superior hindsight has provided, on the file dst_file.
*/
register struct stack_entry *se = local_level->sl_entry;
if (C_open(dst_file) == 0)
fatal("cannot create %s", dst_file ? dst_file : "stdout");
famous_first_words();
while (se != 0) {
register struct idf *id = se->se_idf;
register struct def *df = id->id_def;
if (df && (df->df_initialized || df->df_used || df->df_alloc))
code_scope(id->id_text, df);
se = se->next;
}
C_close();
}
#endif USE_TMP
code_scope(text, def)
char *text;
register struct def *def;
{
/* generates code for one name, text, of the storage class
as given by def, if meaningful.
*/
int fund = def->df_type->tp_fund;
switch (def->df_sc) {
case EXTERN:
case GLOBAL:
case IMPLICIT:
if (fund == FUNCTION)
C_exp(text);
else
C_exa_dnam(text);
break;
case STATIC:
if (fund == FUNCTION)
C_inp(text);
else
C_ina_dnam(text);
break;
}
}
static label return_label;
static char return_expr_occurred;
static struct type *func_tp;
static label func_res_label;
static char *last_fn_given = "";
static label file_name_label;
begin_proc(name, def) /* to be called when entering a procedure */
char *name;
register struct def *def;
{
/* begin_proc() is called at the entrance of a new function
and performs the necessary code generation:
- a scope indicator (if needed) exp/inp
- the procedure entry pro $name
- reserves some space if the result of the function
does not fit in the return area
- a fil pseudo instruction
*/
arith size;
register struct type *tp = def->df_type;
#ifdef USE_TMP
if (options['N']) code_scope(name,def);
#else USE_TMP
code_scope(name, def);
#endif USE_TMP
#ifdef DATAFLOW
if (options['d'])
DfaStartFunction(name);
#endif DATAFLOW
if (tp->tp_fund != FUNCTION) {
error("making function body for non-function");
tp = error_type;
}
else
tp = tp->tp_up;
func_tp = tp;
size = ATW(tp->tp_size);
C_pro_narg(name);
if (is_struct_or_union(tp->tp_fund)) {
C_df_dlb(func_res_label = data_label());
C_bss_cst(size, (arith)0, 1);
}
else
func_res_label = 0;
/* Special arrangements if the function result doesn't fit in
the function return area of the EM machine. The size of
the function return area is implementation dependent.
*/
lab_count = (label) 1;
return_label = text_label();
return_expr_occurred = 0;
prc_entry(name);
if (! options['L']) { /* profiling */
if (strcmp(last_fn_given, FileName) != 0) {
/* previous function came from other file */
C_df_dlb(file_name_label = data_label());
C_con_scon(last_fn_given = FileName,
(arith)(strlen(FileName) + 1));
}
/* enable debug trace of EM source */
C_fil_dlb(file_name_label, (arith)0);
C_lin((arith)LineNumber);
}
}
end_proc(fbytes, nbytes)
arith fbytes, nbytes;
{
/* end_proc() deals with the code to be generated at the end of
a function, as there is:
- the EM ret instruction: "ret 0"
- loading of the function result in the function
result area if there has been a return <expr>
in the function body (see do_return_expr())
- indication of the use of floating points
- indication of the number of bytes used for
formal parameters
- use of special identifiers such as "setjmp"
- "end" + number of bytes used for local variables
*/
static int mes_flt_given = 0; /* once for the whole program */
#ifdef DATAFLOW
if (options['d'])
DfaEndFunction();
#endif DATAFLOW
prc_exit();
C_ret((arith)0);
if (return_expr_occurred != 0) {
C_df_ilb(return_label);
prc_exit();
if (func_res_label != 0) {
C_lae_dlb(func_res_label, (arith)0);
store_block(func_tp->tp_size, func_tp->tp_align);
C_lae_dlb(func_res_label, (arith)0);
C_ret(pointer_size);
}
else
C_ret(ATW(func_tp->tp_size));
}
#ifndef NOFLOAT
if (fp_used && mes_flt_given == 0) {
/* floating point used */
C_ms_flt();
mes_flt_given++;
}
#endif NOFLOAT
C_ms_par(fbytes); /* # bytes for formals */
if (sp_occurred[SP_SETJMP]) { /* indicate use of "setjmp" */
C_ms_gto();
sp_occurred[SP_SETJMP] = 0;
}
C_end(ATW(nbytes));
}
do_return()
{
/* do_return generates a direct return */
/* isn't a jump to the return label smarter ??? */
prc_exit();
C_ret((arith)0);
}
do_return_expr(expr)
struct expr *expr;
{
/* do_return_expr() generates the expression and the jump for
a return statement with an expression.
*/
ch7cast(&expr, RETURN, func_tp);
code_expr(expr, RVAL, TRUE, NO_LABEL, NO_LABEL);
C_bra(return_label);
return_expr_occurred = 1;
}
code_declaration(idf, expr, lvl, sc)
register struct idf *idf; /* idf to be declared */
struct expr *expr; /* initialisation; NULL if absent */
int lvl; /* declaration level */
int sc; /* storage class, as in the declaration */
{
/* code_declaration() does the actual declaration of the
variable indicated by "idf" on declaration level "lvl".
If the variable is initialised, the expression is given
in "expr".
There are some cases to be considered:
- filter out typedefs, they don't correspond to code;
- global variables, coded only if initialized;
- local static variables;
- local automatic variables;
Since the expression may be modified in the process,
code_declaration() frees it after use, as the caller can
no longer do so.
If there is a storage class indication (EXTERN/STATIC),
code_declaration() will generate an exa or ina.
The sc is the actual storage class, as given in the
declaration. This is to allow:
extern int a;
int a = 5;
while at the same time forbidding
extern int a = 5;
*/
char *text = idf->id_text;
register struct def *def = idf->id_def;
register arith size = def->df_type->tp_size;
int def_sc = def->df_sc;
if (def_sc == TYPEDEF) /* no code for typedefs */
return;
if (sc == EXTERN && expr && !is_anon_idf(idf))
error("%s is extern; cannot initialize", text);
if (lvl == L_GLOBAL) { /* global variable */
/* is this an allocating declaration? */
if ( (sc == 0 || sc == STATIC)
&& def->df_type->tp_fund != FUNCTION
&& size >= 0
)
def->df_alloc = ALLOC_SEEN;
if (expr) { /* code only if initialized */
#ifdef USE_TMP
if (options['N'])
#endif USE_TMP
code_scope(text, def);
def->df_alloc = ALLOC_DONE;
C_df_dnam(text);
do_ival(&(def->df_type), expr);
free_expression(expr);
}
}
else
if (lvl >= L_LOCAL) { /* local variable */
/* STATIC, EXTERN, GLOBAL, IMPLICIT, AUTO or REGISTER */
switch (def_sc) {
case STATIC:
if (def->df_type->tp_fund == FUNCTION) {
/* should produce "inp $function" ??? */
break;
}
/* they are handled on the spot and get an
integer label in EM.
*/
C_df_dlb((label)def->df_address);
if (expr) { /* there is an initialisation */
do_ival(&(def->df_type), expr);
free_expression(expr);
}
else { /* produce blank space */
if (size <= 0) {
error("size of %s unknown", text);
size = (arith)0;
}
C_bss_cst(align(size, word_align), (arith)0, 1);
}
break;
case EXTERN:
case GLOBAL:
case IMPLICIT:
/* we are sure there is no expression */
#ifdef USE_TMP
if (options['N'])
#endif USE_TMP
code_scope(text, def);
break;
case AUTO:
case REGISTER:
if (expr)
loc_init(expr, idf);
break;
default:
crash("bad local storage class");
break;
}
}
}
loc_init(expr, id)
struct expr *expr;
register struct idf *id;
{
/* loc_init() generates code for the assignment of
expression expr to the local variable described by id.
It frees the expression afterwards.
*/
register struct type *tp = id->id_def->df_type;
register struct expr *e = expr;
ASSERT(id->id_def->df_sc != STATIC);
switch (tp->tp_fund) {
case ARRAY:
case STRUCT:
case UNION:
error("no automatic aggregate initialisation");
free_expression(e);
return;
}
if (ISCOMMA(e)) { /* embraced: int i = {12}; */
if (options['R']) {
if (ISCOMMA(e->OP_LEFT)) /* int i = {{1}} */
expr_error(e, "extra braces not allowed");
else
if (e->OP_RIGHT != 0) /* int i = {1 , 2} */
expr_error(e, "too many initializers");
}
while (e) {
loc_init(e->OP_LEFT, id);
e = e->OP_RIGHT;
}
}
else { /* not embraced */
struct value vl;
ch7cast(&expr, '=', tp); /* may modify expr */
EVAL(expr, RVAL, TRUE, NO_LABEL, NO_LABEL);
free_expression(expr);
vl.vl_class = Name;
vl.vl_data.vl_idf = id;
vl.vl_value = (arith)0;
store_val(&vl, tp);
}
}
bss(idf)
register struct idf *idf;
{
/* bss() allocates bss space for the global idf.
*/
arith size = idf->id_def->df_type->tp_size;
#ifdef USE_TMP
if (options['N'])
#endif USE_TMP
code_scope(idf->id_text, idf->id_def);
/* Since bss() is only called if df_alloc is non-zero, and
since df_alloc is only non-zero if size >= 0, we have:
*/
/* but we already gave a warning at the declaration of the
array. Besides, the message given here does not apply to
voids
if (options['R'] && size == 0)
warning("actual array of size 0");
*/
C_df_dnam(idf->id_text);
C_bss_cst(align(size, word_align), (arith)0, 1);
}
formal_cvt(df)
register struct def *df;
{
/* formal_cvt() converts a formal parameter of type char or
short from int to that type.
*/
register struct type *tp = df->df_type;
if (tp->tp_size != int_size &&
(tp->tp_fund == CHAR || tp->tp_fund == SHORT)
) {
C_lol(df->df_address);
/* conversion(int_type, df->df_type); ???
No, you can't do this on the stack! (CJ)
*/
C_lal(df->df_address);
C_sti(tp->tp_size);
df->df_register = REG_NONE;
}
}
code_expr(expr, val, code, tlbl, flbl)
struct expr *expr;
label tlbl, flbl;
{
/* code_expr() is the parser's interface to the expression code
generator. If line number trace is wanted, it generates a
lin instruction. EVAL() is called directly.
*/
if (! options['L']) /* profiling */
C_lin((arith)LineNumber);
EVAL(expr, val, code, tlbl, flbl);
}
/* The FOR/WHILE/DO/SWITCH stacking mechanism:
stack_stmt() has to be called at the entrance of a
for, while, do or switch statement to indicate the
EM labels where a subsequent break or continue causes
the program to jump to.
*/
static struct stmt_block *stmt_stack; /* top of statement stack */
/* code_break() generates EM code needed at the occurrence of "break":
it generates a branch instruction to the break label of the
innermost statement in which break has a meaning.
As "break" is legal in any of 'while', 'do', 'for' or 'switch',
which are the only ones that are stacked, only the top of
the stack is interesting.
*/
code_break()
{
register struct stmt_block *stmt_block = stmt_stack;
if (stmt_block)
C_bra(stmt_block->st_break);
else
error("break not inside for, while, do or switch");
}
/* code_continue() generates EM code needed at the occurrence of
"continue":
it generates a branch instruction to the continue label of the
innermost statement in which continue has a meaning.
*/
code_continue()
{
register struct stmt_block *stmt_block = stmt_stack;
while (stmt_block) {
if (stmt_block->st_continue) {
C_bra(stmt_block->st_continue);
return;
}
stmt_block = stmt_block->next;
}
error("continue not inside for, while or do");
}
stack_stmt(break_label, cont_label)
label break_label, cont_label;
{
register struct stmt_block *stmt_block = new_stmt_block();
stmt_block->next = stmt_stack;
stmt_block->st_break = break_label;
stmt_block->st_continue = cont_label;
stmt_stack = stmt_block;
}
unstack_stmt()
{
/* unstack_stmt() unstacks the data of a statement
which may contain break or continue
*/
register struct stmt_block *sbp = stmt_stack;
stmt_stack = sbp->next;
free_stmt_block(sbp);
}
static label l1;
prc_entry(name)
char *name;
{
if (options['p']) {
C_df_dlb(l1 = data_label());
C_rom_scon(name, (arith) (strlen(name) + 1));
C_lae_dlb(l1, (arith) 0);
C_cal("procentry");
C_asp(pointer_size);
}
}
prc_exit()
{
if (options['p']) {
C_lae_dlb(l1, (arith) 0);
C_cal("procexit");
C_asp(pointer_size);
}
}