376 lines
7.4 KiB
C
376 lines
7.4 KiB
C
/* D E S I G N A T O R E V A L U A T I O N */
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/* Code generation for designators.
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This file contains some routines that generate code common to address
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as well as value computations, and leave a description in a "desig"
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structure. It also contains routines to load an address, load a value
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or perform a store.
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*/
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#include "debug.h"
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#include <em_arith.h>
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#include <em_label.h>
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#include <em_code.h>
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#include <assert.h>
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#include "type.h"
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#include "def.h"
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#include "scope.h"
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#include "desig.h"
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#include "LLlex.h"
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#include "node.h"
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extern int proclevel;
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struct desig InitDesig = {DSG_INIT, 0, 0};
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CodeValue(ds, size)
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register struct desig *ds;
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arith size;
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{
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/* Generate code to load the value of the designator described
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in "ds"
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*/
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switch(ds->dsg_kind) {
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case DSG_LOADED:
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break;
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case DSG_FIXED:
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if (size == word_size) {
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if (ds->dsg_name) {
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C_loe_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_lol(ds->dsg_offset);
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break;
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}
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if (size == dword_size) {
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if (ds->dsg_name) {
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C_lde_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_ldl(ds->dsg_offset);
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break;
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}
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/* Fall through */
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case DSG_PLOADED:
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case DSG_PFIXED:
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CodeAddress(ds);
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C_loi(size);
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break;
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case DSG_INDEXED:
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C_lar(word_size);
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break;
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default:
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crash("(CodeValue)");
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}
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ds->dsg_kind = DSG_LOADED;
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}
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CodeStore(ds, size)
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register struct desig *ds;
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arith size;
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{
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/* Generate code to store the value on the stack in the designator
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described in "ds"
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*/
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switch(ds->dsg_kind) {
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case DSG_FIXED:
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if (size == word_size) {
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if (ds->dsg_name) {
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C_ste_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_stl(ds->dsg_offset);
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break;
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}
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if (size == dword_size) {
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if (ds->dsg_name) {
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C_sde_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_sdl(ds->dsg_offset);
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break;
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}
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/* Fall through */
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case DSG_PLOADED:
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case DSG_PFIXED:
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CodeAddress(ds);
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C_sti(size);
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break;
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case DSG_INDEXED:
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C_sar(word_size);
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break;
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default:
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crash("(CodeStore)");
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}
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ds->dsg_kind = DSG_INIT;
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}
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CodeAddress(ds)
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register struct desig *ds;
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{
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/* Generate code to load the address of the designator described
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in "ds"
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*/
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switch(ds->dsg_kind) {
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case DSG_PLOADED:
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if (ds->dsg_offset) {
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C_adp(ds->dsg_offset);
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}
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break;
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case DSG_FIXED:
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if (ds->dsg_name) {
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C_lae_dnam(ds->dsg_name, ds->dsg_offset);
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break;
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}
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C_lal(ds->dsg_offset);
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break;
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case DSG_PFIXED:
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ds->dsg_kind = DSG_FIXED;
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CodeValue(ds, pointer_size);
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break;
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case DSG_INDEXED:
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C_aar(word_size);
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break;
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default:
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crash("(CodeAddress)");
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}
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ds->dsg_offset = 0;
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ds->dsg_kind = DSG_PLOADED;
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}
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CodeFieldDesig(df, ds)
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register struct def *df;
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register struct desig *ds;
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{
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/* Generate code for a field designator. Only the code common for
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address as well as value computation is generated, and the
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resulting information on where to find the designator is placed
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in "ds". "df" indicates the definition of the field.
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*/
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if (ds->dsg_kind == DSG_INIT) {
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/* In a WITH statement. We must find the designator in the
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WITH statement, and act as if the field is a selection
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of this designator.
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So, first find the right WITH statement, which is the
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first one of the proper record type, which is
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recognized by its scope indication.
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*/
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register struct withdesig *wds = WithDesigs;
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assert(wds != 0);
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while (wds->w_scope != df->df_scope) {
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wds = wds->w_next;
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assert(wds != 0);
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}
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/* Found it. Now, act like it was a selection.
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*/
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*ds = wds->w_desig;
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assert(ds->dsg_kind == DSG_PFIXED);
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}
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switch(ds->dsg_kind) {
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case DSG_PLOADED:
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case DSG_FIXED:
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ds->dsg_offset += df->fld_off;
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break;
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case DSG_PFIXED:
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case DSG_INDEXED:
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CodeAddress(ds);
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ds->dsg_kind = DSG_PLOADED;
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ds->dsg_offset = df->fld_off;
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break;
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default:
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crash("(CodeFieldDesig)");
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}
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}
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CodeVarDesig(df, ds)
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register struct def *df;
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register struct desig *ds;
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{
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/* Generate code for a variable represented by a "def" structure.
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Of course, there are numerous cases: the variable is local,
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it is a value parameter, it is a var parameter, it is one of
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those of an enclosing procedure, or it is global.
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*/
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register struct scope *sc = df->df_scope;
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/* Selections from a module are handled earlier, when identifying
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the variable, so ...
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*/
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assert(ds->dsg_kind == DSG_INIT);
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SetUsed(df);
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if (df->var_addrgiven) {
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/* the programmer specified an address in the declaration of
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the variable. Generate code to push the address.
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*/
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CodeConst(df->var_off, pointer_size);
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ds->dsg_kind = DSG_PLOADED;
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ds->dsg_offset = 0;
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return;
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}
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if (df->var_name) {
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/* this variable has been given a name, so it is global.
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It is directly accessible.
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*/
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ds->dsg_name = df->var_name;
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ds->dsg_offset = 0;
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ds->dsg_kind = DSG_FIXED;
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return;
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}
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if (sc->sc_level != proclevel) {
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/* the variable is local to a statically enclosing procedure.
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*/
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assert(proclevel > sc->sc_level);
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df->df_flags |= D_NOREG;
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if (df->df_flags & (D_VARPAR|D_VALPAR)) {
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/* value or var parameter
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*/
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C_lxa((arith) (proclevel - sc->sc_level));
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if ((df->df_flags & D_VARPAR) ||
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IsConformantArray(df->df_type)) {
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/* var parameter or conformant array.
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For conformant array's, the address is
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passed.
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*/
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C_adp(df->var_off);
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C_loi(pointer_size);
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ds->dsg_offset = 0;
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ds->dsg_kind = DSG_PLOADED;
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return;
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}
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}
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else C_lxl((arith) (proclevel - sc->sc_level));
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ds->dsg_kind = DSG_PLOADED;
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ds->dsg_offset = df->var_off;
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return;
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}
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/* Now, finally, we have a local variable or a local parameter
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*/
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if ((df->df_flags & D_VARPAR) || IsConformantArray(df->df_type)) {
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/* a var parameter; address directly accessible.
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*/
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ds->dsg_kind = DSG_PFIXED;
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}
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else ds->dsg_kind = DSG_FIXED;
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ds->dsg_offset =df->var_off;
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}
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CodeDesig(nd, ds)
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register struct node *nd;
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register struct desig *ds;
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{
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/* Generate code for a designator. Use divide and conquer
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principle
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*/
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register struct def *df;
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switch(nd->nd_class) { /* Divide */
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case Def:
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df = nd->nd_def;
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SetUsed(df);
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switch(df->df_kind) {
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case D_FIELD:
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CodeFieldDesig(df, ds);
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break;
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case D_VARIABLE:
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CodeVarDesig(df, ds);
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break;
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default:
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crash("(CodeDesig) Def");
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}
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break;
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case LinkDef:
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assert(nd->nd_symb == '.');
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CodeDesig(nd->nd_left, ds);
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CodeFieldDesig(nd->nd_def, ds);
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break;
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case Arrsel:
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assert(nd->nd_symb == '[');
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CodeDesig(nd->nd_left, ds);
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CodeAddress(ds);
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CodePExpr(nd->nd_right);
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if (nd->nd_right->nd_type->tp_size > word_size) {
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CodeCoercion(nd->nd_right->nd_type, int_type);
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}
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/* Now load address of descriptor
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*/
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if (IsConformantArray(nd->nd_left->nd_type)) {
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assert(nd->nd_left->nd_class == Def);
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df = nd->nd_left->nd_def;
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if (proclevel > df->df_scope->sc_level) {
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C_lxa((arith) (proclevel - df->df_scope->sc_level));
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C_adp(df->var_off + pointer_size);
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}
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else C_lal(df->var_off + pointer_size);
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}
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else {
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C_lae_dlb(nd->nd_left->nd_type->arr_descr, (arith) 0);
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}
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ds->dsg_kind = DSG_INDEXED;
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break;
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case Arrow:
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assert(nd->nd_symb == '^');
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CodeDesig(nd->nd_right, ds);
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switch(ds->dsg_kind) {
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case DSG_LOADED:
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ds->dsg_kind = DSG_PLOADED;
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break;
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case DSG_INDEXED:
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case DSG_PLOADED:
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case DSG_PFIXED:
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CodeValue(ds, pointer_size);
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ds->dsg_kind = DSG_PLOADED;
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ds->dsg_offset = 0;
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break;
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case DSG_FIXED:
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ds->dsg_kind = DSG_PFIXED;
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break;
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default:
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crash("(CodeDesig) Uoper");
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}
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break;
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default:
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crash("(CodeDesig) class");
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}
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}
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