602 lines
12 KiB
C
602 lines
12 KiB
C
/* P A R S E T R E E W A L K E R */
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#ifndef NORCSID
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static char *RcsId = "$Header$";
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#endif
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/* Routines to walk through parts of the parse tree, and generate
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code for these parts.
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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 <assert.h>
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#include "def.h"
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#include "type.h"
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#include "scope.h"
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#include "main.h"
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#include "LLlex.h"
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#include "node.h"
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#include "Lpars.h"
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#include "desig.h"
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#include "f_info.h"
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#include "idf.h"
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extern arith NewPtr();
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extern arith NewInt();
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extern int proclevel;
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static label instructionlabel;
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static char return_expr_occurred;
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static struct type *func_type;
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struct withdesig *WithDesigs;
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struct node *Modules;
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label
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text_label()
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{
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return instructionlabel++;
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}
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label
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data_label()
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{
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static label datalabel = 0;
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return ++datalabel;
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}
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static
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DoProfil()
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{
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static label filename_label = 0;
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if (! options['L']) {
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if (!filename_label) {
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filename_label = data_label();
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C_df_dlb(filename_label);
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C_rom_scon(FileName, (arith) (strlen(FileName) + 1));
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}
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C_fil_dlb(filename_label, (arith) 0);
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}
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}
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WalkModule(module)
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register struct def *module;
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{
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/* Walk through a module, and all its local definitions.
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Also generate code for its body.
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*/
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register struct def *df = module->mod_vis->sc_scope->sc_def;
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register struct scope *sc;
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struct scopelist *vis;
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vis = CurrVis;
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CurrVis = module->mod_vis;
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sc = CurrentScope;
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if (!proclevel && module != Defined) {
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/* This module is a local module, but not within a
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procedure. Generate code to allocate storage for its
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variables. This is done by generating a "bss",
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with label "_<modulenumber><modulename>".
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*/
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arith size = align(sc->sc_off, word_align);
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if (size == 0) size = word_size;
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/* WHY ??? because we generated an INA for it ??? */
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C_df_dnam(&(sc->sc_name[1]));
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size = align(size, word_align);
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C_bss_cst(size, (arith) 0, 0);
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C_exp(sc->sc_name);
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}
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else if (CurrVis == Defined->mod_vis) {
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/* This module is the module currently being compiled.
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Again, generate code to allocate storage for its
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variables, which all have an explicit name.
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*/
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while (df) {
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if (df->df_kind == D_VARIABLE) {
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C_df_dnam(df->var_name);
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C_bss_cst(
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align(df->df_type->tp_size, word_align),
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(arith) 0, 0);
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}
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df = df->df_nextinscope;
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}
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if (state == PROGRAM) C_exp("main");
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else C_exp(sc->sc_name);
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}
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/* Now, walk through it's local definitions
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*/
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WalkDef(sc->sc_def);
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/* Now, generate initialization code for this module.
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First call initialization routines for modules defined within
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this module.
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*/
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sc->sc_off = 0;
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instructionlabel = 2;
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func_type = 0;
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C_pro_narg(state == PROGRAM ? "main" : sc->sc_name);
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DoProfil();
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if (CurrVis == Defined->mod_vis) {
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/* Body of implementation or program module.
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Call initialization routines of imported modules.
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Also prevent recursive calls of this one.
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*/
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struct node *nd;
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if (state == IMPLEMENTATION) {
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label l1 = data_label(), l2 = text_label();
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/* we don't actually prevent recursive calls,
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but do nothing if called recursively
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*/
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C_df_dlb(l1);
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C_bss_cst(word_size, (arith) 0, 1);
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C_loe_dlb(l1, (arith) 0);
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C_zeq(l2);
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C_ret((arith) 0);
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C_df_ilb(l2);
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C_loc((arith) 1);
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C_ste_dlb(l1, (arith) 0);
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}
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nd = Modules;
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while (nd) {
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C_cal(nd->nd_IDF->id_text);
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nd = nd->next;
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}
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}
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MkCalls(sc->sc_def);
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proclevel++;
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WalkNode(module->mod_body, (label) 0);
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C_df_ilb((label) 1);
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C_ret((arith) 0);
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C_end(-sc->sc_off);
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proclevel--;
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TmpClose();
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CurrVis = vis;
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}
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WalkProcedure(procedure)
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register struct def *procedure;
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{
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/* Walk through the definition of a procedure and all its
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local definitions
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*/
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struct scopelist *vis = CurrVis;
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register struct scope *sc;
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register struct type *res_type;
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proclevel++;
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CurrVis = procedure->prc_vis;
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sc = CurrentScope;
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WalkDef(sc->sc_def);
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/* Generate code for this procedure
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*/
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C_pro_narg(sc->sc_name);
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DoProfil();
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/* generate calls to initialization routines of modules defined within
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this procedure
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*/
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MkCalls(sc->sc_def);
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return_expr_occurred = 0;
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instructionlabel = 2;
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func_type = res_type = procedure->df_type->next;
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if (! returntype(res_type)) {
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node_error(procedure->prc_body, "illegal result type");
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}
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WalkNode(procedure->prc_body, (label) 0);
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C_df_ilb((label) 1);
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if (res_type) {
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if (! return_expr_occurred) {
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node_error(procedure->prc_body,"function procedure does not return a value");
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}
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C_ret(align(res_type->tp_size, word_align));
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}
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else C_ret((arith) 0);
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C_end(-sc->sc_off);
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TmpClose();
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CurrVis = vis;
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proclevel--;
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}
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WalkDef(df)
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register struct def *df;
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{
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/* Walk through a list of definitions
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*/
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while (df) {
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if (df->df_kind == D_MODULE) {
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WalkModule(df);
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}
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else if (df->df_kind == D_PROCEDURE) {
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WalkProcedure(df);
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}
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df = df->df_nextinscope;
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}
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}
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MkCalls(df)
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register struct def *df;
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{
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/* Generate calls to initialization routines of modules
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*/
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while (df) {
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if (df->df_kind == D_MODULE) {
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C_lxl((arith) 0);
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C_cal(df->mod_vis->sc_scope->sc_name);
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C_asp(pointer_size);
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}
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df = df->df_nextinscope;
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}
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}
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WalkNode(nd, lab)
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register struct node *nd;
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label lab;
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{
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/* Node "nd" represents either a statement or a statement list.
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Walk through it.
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"lab" represents the label that must be jumped to on
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encountering an EXIT statement.
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*/
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while (nd->nd_class == Link) { /* statement list */
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WalkStat(nd->nd_left, lab);
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nd = nd->nd_right;
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}
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WalkStat(nd, lab);
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}
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WalkStat(nd, lab)
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struct node *nd;
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label lab;
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{
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/* Walk through a statement, generating code for it.
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"lab" represents the label that must be jumped to on
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encountering an EXIT statement.
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*/
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register struct node *left = nd->nd_left;
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register struct node *right = nd->nd_right;
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register struct desig *pds = &Desig;
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if (!nd) {
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/* Empty statement
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*/
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return;
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}
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if (! options['L']) C_lin((arith) nd->nd_lineno);
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if (nd->nd_class == Call) {
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if (chk_call(nd)) {
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if (nd->nd_type != 0) {
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node_error(nd, "procedure call expected");
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return;
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}
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CodeCall(nd);
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}
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return;
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}
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assert(nd->nd_class == Stat);
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switch(nd->nd_symb) {
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case BECOMES:
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DoAssign(nd, left, right);
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break;
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case IF:
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{ label l1, l2, l3;
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l1 = instructionlabel++;
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l2 = instructionlabel++;
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l3 = instructionlabel++;
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ExpectBool(left, l3, l1);
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assert(right->nd_symb == THEN);
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C_df_ilb(l3);
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WalkNode(right->nd_left, lab);
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if (right->nd_right) { /* ELSE part */
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C_bra(l2);
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C_df_ilb(l1);
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WalkNode(right->nd_right, lab);
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C_df_ilb(l2);
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}
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else C_df_ilb(l1);
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break;
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}
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case CASE:
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CaseCode(nd, lab);
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break;
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case WHILE:
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{ label l1, l2, l3;
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l1 = instructionlabel++;
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l2 = instructionlabel++;
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l3 = instructionlabel++;
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C_df_ilb(l1);
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ExpectBool(left, l3, l2);
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C_df_ilb(l3);
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WalkNode(right, lab);
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C_bra(l1);
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C_df_ilb(l2);
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break;
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}
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case REPEAT:
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{ label l1, l2;
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l1 = instructionlabel++;
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l2 = instructionlabel++;
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C_df_ilb(l1);
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WalkNode(left, lab);
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ExpectBool(right, l2, l1);
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C_df_ilb(l2);
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break;
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}
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case LOOP:
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{ label l1, l2;
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l1 = instructionlabel++;
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l2 = instructionlabel++;
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C_df_ilb(l1);
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WalkNode(left, l2);
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C_bra(l1);
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C_df_ilb(l2);
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break;
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}
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case FOR:
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{
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arith tmp = 0;
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struct node *fnd;
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label l1 = instructionlabel++;
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label l2 = instructionlabel++;
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arith size;
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if (! DoForInit(nd, left)) break;
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fnd = left->nd_right;
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size = fnd->nd_type->tp_size;
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if (fnd->nd_class != Value) {
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CodePExpr(fnd);
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tmp = NewInt();
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C_stl(tmp);
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}
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C_bra(l1);
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C_df_ilb(l2);
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WalkNode(right, lab);
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C_loc(left->nd_INT);
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CodePExpr(nd);
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C_adi(int_size);
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CodeDStore(nd);
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C_df_ilb(l1);
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CodePExpr(nd);
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if (tmp) C_lol(tmp); else C_loc(fnd->nd_INT);
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if (left->nd_INT > 0) {
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C_ble(l2);
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}
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else C_bge(l2);
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if (tmp) FreeInt(tmp);
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}
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break;
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case WITH:
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{
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struct scopelist link;
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struct withdesig wds;
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arith tmp = 0;
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WalkDesignator(left);
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if (left->nd_type->tp_fund != T_RECORD) {
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node_error(left, "record variable expected");
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break;
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}
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wds.w_next = WithDesigs;
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WithDesigs = &wds;
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wds.w_scope = left->nd_type->rec_scope;
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if (pds->dsg_kind != DSG_PFIXED) {
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/* In this case, we use a temporary variable
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*/
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CodeAddress(pds);
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pds->dsg_kind = DSG_FIXED;
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/* Only for the store ... */
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pds->dsg_offset = tmp = NewPtr();
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pds->dsg_name = 0;
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CodeStore(pds, pointer_size);
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pds->dsg_kind = DSG_PFIXED;
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/* the record is indirectly available */
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}
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wds.w_desig = *pds;
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link.sc_scope = wds.w_scope;
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link.next = CurrVis;
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CurrVis = &link;
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WalkNode(right, lab);
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CurrVis = link.next;
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WithDesigs = wds.w_next;
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if (tmp) FreePtr(tmp);
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break;
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}
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case EXIT:
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assert(lab != 0);
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C_bra(lab);
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break;
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case RETURN:
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if (right) {
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WalkExpr(right, NO_LABEL, NO_LABEL);
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/* Assignment compatibility? Yes, see Rep. 9.11
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*/
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if (!TstAssCompat(func_type, right->nd_type)) {
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node_error(right, "type incompatibility in RETURN statement");
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}
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return_expr_occurred = 1;
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}
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C_bra((label) 1);
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break;
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default:
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assert(0);
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}
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}
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ExpectBool(nd, true_label, false_label)
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register struct node *nd;
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label true_label, false_label;
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{
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/* "nd" must indicate a boolean expression. Check this and
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generate code to evaluate the expression.
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*/
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WalkExpr(nd, true_label, false_label);
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if (nd->nd_type != bool_type && nd->nd_type != error_type) {
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node_error(nd, "boolean expression expected");
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}
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}
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WalkExpr(nd, true_label, false_label)
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struct node *nd;
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label true_label, false_label;
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{
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/* Check an expression and generate code for it
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*/
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DO_DEBUG(1, (DumpTree(nd), print("\n")));
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if (! chk_expr(nd)) return;
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Desig = InitDesig;
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CodeExpr(nd, &Desig, true_label, false_label);
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}
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WalkDesignator(nd)
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struct node *nd;
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{
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/* Check designator and generate code for it
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*/
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DO_DEBUG(1, (DumpTree(nd), print("\n")));
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if (! chk_designator(nd, DESIGNATOR|VARIABLE, D_DEFINED)) return;
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Desig = InitDesig;
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CodeDesig(nd, &Desig);
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}
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DoForInit(nd, left)
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register struct node *nd, *left;
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{
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nd->nd_left = nd->nd_right = 0;
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nd->nd_class = Name;
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nd->nd_symb = IDENT;
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if (! chk_designator(nd, VARIABLE, D_DEFINED) ||
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! chk_expr(left->nd_left) ||
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! chk_expr(left->nd_right)) return;
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if (nd->nd_type->tp_size > word_size ||
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!(nd->nd_type->tp_fund & T_DISCRETE)) {
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node_error(nd, "illegal type of FOR loop variable");
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return 0;
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}
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if (!TstCompat(nd->nd_type, left->nd_left->nd_type) ||
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!TstCompat(nd->nd_type, left->nd_right->nd_type)) {
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if (!TstAssCompat(nd->nd_type, left->nd_left->nd_type) ||
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!TstAssCompat(nd->nd_type, left->nd_right->nd_type)) {
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node_error(nd, "type incompatibility in FOR statement");
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return 0;
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}
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node_warning(nd, "old-fashioned! compatibility required in FOR statement");
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}
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CodePExpr(left->nd_left);
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CodeDStore(nd);
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}
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DoAssign(nd, left, right)
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struct node *nd;
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register struct node *left, *right;
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{
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/* May we do it in this order (expression first) ??? */
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struct desig ds;
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if (!chk_expr(right)) return;
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if (! chk_designator(left, DESIGNATOR|VARIABLE, D_DEFINED)) return;
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TryToString(right, left->nd_type);
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Desig = InitDesig;
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CodeExpr(right, &Desig, NO_LABEL, NO_LABEL);
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if (! TstAssCompat(left->nd_type, right->nd_type)) {
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node_error(nd, "type incompatibility in assignment");
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return;
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}
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if (complex(right->nd_type)) {
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CodeAddress(&Desig);
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}
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else {
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CodeValue(&Desig, right->nd_type->tp_size);
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CheckAssign(left->nd_type, right->nd_type);
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}
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ds = Desig;
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Desig = InitDesig;
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CodeDesig(left, &Desig);
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CodeAssign(nd, &ds, &Desig);
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}
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#ifdef DEBUG
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DumpTree(nd)
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struct node *nd;
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{
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char *s;
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extern char *symbol2str();
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|
|
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if (!nd) {
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print("()");
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|
return;
|
|
}
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|
|
|
print("(");
|
|
DumpTree(nd->nd_left);
|
|
switch(nd->nd_class) {
|
|
case Def: s = "Def"; break;
|
|
case Oper: s = "Oper"; break;
|
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case Uoper: s = "Uoper"; break;
|
|
case Name: s = "Name"; break;
|
|
case Set: s = "Set"; break;
|
|
case Value: s = "Value"; break;
|
|
case Call: s = "Call"; break;
|
|
case Xset: s = "Xset"; break;
|
|
case Stat: s = "Stat"; break;
|
|
case Link: s = "Link"; break;
|
|
default: s = "ERROR"; break;
|
|
}
|
|
print("%s %s", s, symbol2str(nd->nd_symb));
|
|
DumpTree(nd->nd_right);
|
|
print(")");
|
|
}
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#endif
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