/* Declare variables underneath a declarator tree */
void declare_variables_tac(environment *env, NODE *node, int variable_type, int return_type) {
value *variable_name = NULL;
if (env == NULL || node == NULL) {
return;
}
else if (type_of(node) == ',') {
declare_variables_tac(env, node->left, variable_type, return_type);
declare_variables_tac(env, node->right, variable_type, return_type);
return;
}
else if (type_of(node) == '=') { /* Specific assignment */
variable_name = make_simple(env, node->left, 0, return_type);
}
else if (type_of(node) == LEAF) { /* Undefined assignment */
variable_name = make_simple(env, node->left, 0, return_type);
}
/* Assign variable */
if (variable_name) {
/* Assign a default initialization value for this type */
switch(variable_type) {
case INT:
assign(env, variable_name, int_value(0), 1);
break;
case VOID:
assign(env, variable_name, void_value(), 1);
break;
case FUNCTION:
assign(env, variable_name, null_fn, 1);
break;
}
}
else {
fatal("Could not ascertain variable name!");
}
}
/* Build the correct code in the correct place for the else part */
void build_else_part(environment *env, NODE *node, int true_part, int flag, int return_type) {
if (node==NULL || type_of(node)!=ELSE) return;
if (true_part) {
make_simple(env, node->left, flag, return_type);
}
else {
make_simple(env, node->right, flag, return_type);
}
}
/* Start the TAC generator process at the top of the AST */
tac_quad *start_tac_gen(NODE *tree) {
/* Do a scan for function definitions first */
environment *initial_env;
initial_env = create_environment(NULL);
null_fn = build_null_function();
make_simple(initial_env, tree, INTERPRET_FN_SCAN, INT);
/* Actually generate the TAC */
make_simple(initial_env, tree, 0, 0);
return tac_output;
}
/* Build necessary code for an if statement */
void build_if_stmt(environment *env, NODE *node, int if_count, tac_quad *false_jump, tac_quad *loop_jump, int flag, int return_type) {
char *s_tmp;
value *val1, *val2, *temporary;
if (node==NULL || (type_of(node)!=IF && type_of(node)!=WHILE)) return;
/* LHS is condition */
val1 = make_simple(env, node->left, flag, return_type);
/* Generate if statement */
s_tmp = malloc(sizeof(char) * 25);
sprintf(s_tmp, "__if%dtrue", if_count);
append_code(make_if(val1, s_tmp));
/* Output false branch (i.e. else part) */
if (type_of(node->right)==ELSE) {
/* Build code for false part */
build_else_part(env, node->right, 0, flag, return_type);
}
/* Generate goto end of if statement */
if (false_jump != NULL) {
append_code(false_jump);
}
else {
s_tmp = malloc(sizeof(char) * 25);
sprintf(s_tmp, "__if%dend", if_count);
append_code(make_goto(s_tmp));
}
/* Generate label for start of true branch */
s_tmp = malloc(sizeof(char) * 25);
sprintf(s_tmp, "__if%dtrue", if_count);
append_code(make_label(s_tmp));
/* Output true branch */
if (type_of(node->right)==ELSE) {
/* Build code for true part */
build_else_part(env, node->right, 1, flag, return_type);
}
else {
/* True part is whole right branch */
make_simple(env, node->right, flag, return_type);
}
/* Check if extra loop jump has been specified (for WHILE loops etc) */
if (loop_jump) {
append_code(loop_jump);
}
/* Generate end of IF stmt label */
s_tmp = malloc(sizeof(char) * 25);
sprintf(s_tmp, "__if%dend", if_count);
append_code(make_label(s_tmp));
}
/**
* g forces the graph to have symmetric adjacency lists and be simple (no loops/duplicate edges) and updates flags accordingly.
*/
void GraphProperties::make_canonical(Graph *g){
// CSG -Should we also have g->capacity==g->num_nodes?
make_simple(g);
g->canonical = true;
return;
}
static CMARK_INLINE cmark_node *make_autolink(cmark_mem *mem, cmark_chunk url,
int is_email) {
cmark_node *link = make_simple(mem, CMARK_NODE_LINK);
link->as.link.url = cmark_clean_autolink(mem, &url, is_email);
link->as.link.title = cmark_chunk_literal("");
cmark_node_append_child(link, make_str_with_entities(mem, &url));
return link;
}
/* Go down the declarator tree initialising the variables, at this stage */
void register_variable_subtree_tac(environment *env, NODE *node, int return_type) {
NODE *original_node = node;
/* Ensure we have all required params */
if (!env || !node || type_of(node) != '~') return;
/* Skip over LEAF nodes */
if (node->left != NULL && type_of(node->left) == LEAF) {
node = node->left;
}
if (node->left != NULL && (type_of(node->left) == VOID || type_of(node->left) == FUNCTION || type_of(node->left) == INT)) {
/* Find variable type */
int variable_type = to_int(NULL, make_simple(env, node->left, 0, return_type));
declare_variables_tac(env, original_node->right, variable_type, return_type);
}
}
// Return a link, an image, or a literal close bracket.
static cmark_node *handle_close_bracket(subject *subj) {
bufsize_t initial_pos, after_link_text_pos;
bufsize_t endurl, starttitle, endtitle, endall;
bufsize_t sps, n;
cmark_reference *ref = NULL;
cmark_chunk url_chunk, title_chunk;
cmark_chunk url, title;
bracket *opener;
cmark_node *inl;
cmark_chunk raw_label;
int found_label;
cmark_node *tmp, *tmpnext;
bool is_image;
advance(subj); // advance past ]
initial_pos = subj->pos;
// get last [ or ![
opener = subj->last_bracket;
if (opener == NULL) {
return make_str(subj->mem, cmark_chunk_literal("]"));
}
if (!opener->active) {
// take delimiter off stack
pop_bracket(subj);
return make_str(subj->mem, cmark_chunk_literal("]"));
}
// If we got here, we matched a potential link/image text.
// Now we check to see if it's a link/image.
is_image = opener->image;
after_link_text_pos = subj->pos;
// First, look for an inline link.
if (peek_char(subj) == '(' &&
((sps = scan_spacechars(&subj->input, subj->pos + 1)) > -1) &&
((n = manual_scan_link_url(&subj->input, subj->pos + 1 + sps, &url_chunk)) > -1)) {
// try to parse an explicit link:
endurl = subj->pos + 1 + sps + n;
starttitle = endurl + scan_spacechars(&subj->input, endurl);
// ensure there are spaces btw url and title
endtitle = (starttitle == endurl)
? starttitle
: starttitle + scan_link_title(&subj->input, starttitle);
endall = endtitle + scan_spacechars(&subj->input, endtitle);
if (peek_at(subj, endall) == ')') {
subj->pos = endall + 1;
title_chunk =
cmark_chunk_dup(&subj->input, starttitle, endtitle - starttitle);
url = cmark_clean_url(subj->mem, &url_chunk);
title = cmark_clean_title(subj->mem, &title_chunk);
cmark_chunk_free(subj->mem, &url_chunk);
cmark_chunk_free(subj->mem, &title_chunk);
goto match;
} else {
// it could still be a shortcut reference link
subj->pos = after_link_text_pos;
}
}
// Next, look for a following [link label] that matches in refmap.
// skip spaces
raw_label = cmark_chunk_literal("");
found_label = link_label(subj, &raw_label);
if (!found_label) {
// If we have a shortcut reference link, back up
// to before the spacse we skipped.
subj->pos = initial_pos;
}
if ((!found_label || raw_label.len == 0) && !opener->bracket_after) {
cmark_chunk_free(subj->mem, &raw_label);
raw_label = cmark_chunk_dup(&subj->input, opener->position,
initial_pos - opener->position - 1);
found_label = true;
}
if (found_label) {
ref = cmark_reference_lookup(subj->refmap, &raw_label);
cmark_chunk_free(subj->mem, &raw_label);
}
if (ref != NULL) { // found
url = chunk_clone(subj->mem, &ref->url);
title = chunk_clone(subj->mem, &ref->title);
goto match;
} else {
goto noMatch;
}
noMatch:
// If we fall through to here, it means we didn't match a link:
pop_bracket(subj); // remove this opener from delimiter list
subj->pos = initial_pos;
return make_str(subj->mem, cmark_chunk_literal("]"));
match:
inl = make_simple(subj->mem, is_image ? CMARK_NODE_IMAGE : CMARK_NODE_LINK);
inl->as.link.url = url;
inl->as.link.title = title;
cmark_node_insert_before(opener->inl_text, inl);
// Add link text:
tmp = opener->inl_text->next;
while (tmp) {
tmpnext = tmp->next;
cmark_node_append_child(inl, tmp);
tmp = tmpnext;
}
// Free the bracket [:
cmark_node_free(opener->inl_text);
process_emphasis(subj, opener->previous_delimiter);
pop_bracket(subj);
// Now, if we have a link, we also want to deactivate earlier link
// delimiters. (This code can be removed if we decide to allow links
// inside links.)
if (!is_image) {
opener = subj->last_bracket;
while (opener != NULL) {
if (!opener->image) {
if (!opener->active) {
break;
} else {
opener->active = false;
}
}
opener = opener->previous;
}
}
return NULL;
}
/*
* Make the given NODE simple - i.e. return a temporary for complex subtrees
* The appropriate code is also generated and pushed onto the code stack
*/
value *make_simple(environment *env, NODE *node, int flag, int return_type) {
int i_value = 0;
char *s_tmp = NULL;
value *val1 = NULL, *val2 = NULL, *temporary = NULL, *temp = NULL;
static int if_count = 0;
static int while_count = 0;
tac_quad *temp_quad = NULL;
environment *new_env = NULL;
if (node==NULL) return NULL;
switch(type_of(node)) {
case LEAF:
return make_simple(env, node->left, flag, return_type);
case CONSTANT:
i_value = cast_from_node(node)->value;
s_tmp = malloc(sizeof(char) * 25);
sprintf(s_tmp, "%d", i_value);
return int_value(i_value);
case IDENTIFIER:
return string_value(cast_from_node(node)->lexeme);
case IF:
build_if_stmt(env, node, ++if_count, NULL, NULL, flag, return_type);
return NULL;
case BREAK:
s_tmp = malloc(sizeof(char) * 25);
sprintf(s_tmp, "__while%dend", while_count);
append_code(make_goto(s_tmp));
return NULL;
case CONTINUE:
s_tmp = malloc(sizeof(char) * 25);
sprintf(s_tmp, "__while%d", while_count);
append_code(make_goto(s_tmp));
return NULL;
case WHILE:
build_while_stmt(env, node, ++while_count, ++if_count, flag, return_type);
return NULL;
case '=':
if (flag == INTERPRET_FN_SCAN) return NULL;
val1 = make_simple(env, node->left, flag, return_type);
val2 = make_simple(env, node->right, flag, return_type);
if (val2 && val2->value_type!=VT_INTEGR && val2->value_type!=VT_FUNCTN) {
if (val2->value_type == VT_STRING) {
val2 = get(env, val2->data.string_value);
}
else {
val2 = get(env, val2->identifier);
}
if (!val2) fatal("Undeclared identifier");
}
/* Check the LHS variable has already been defined */
temp = get(env, to_string(val1));
assert(temp!=NULL, "Variable not defined");
/* Type check the assignment */
type_check_assignment(val1, val2, vt_type_convert(temp->value_type));
temporary = assign(env, val1, val2, 0);
if (flag != INTERPRET_FN_SCAN) append_code(make_quad_value("=", val2, NULL, temporary, TT_ASSIGN, 0));
return NULL;
case '*':
case '/':
case '>':
case '<':
case '%':
case '-':
case '+':
case NE_OP:
case LE_OP:
case GE_OP:
case EQ_OP:
temporary = generate_temporary(env, int_value(0));
val1 = make_simple(env, node->left, flag, return_type);
val2 = make_simple(env, node->right, flag, return_type);
if (val1->value_type==VT_STRING) val1 = get(env, correct_string_rep(val1));
if (val2->value_type==VT_STRING) val2 = get(env, correct_string_rep(val2));
assert(val1 != NULL, "Operand value 1 must not be null");
assert(val2 != NULL, "Operand value 2 must not be null");
if (flag != INTERPRET_FN_SCAN) append_code(make_quad_value(type_to_string(type_of(node)), val1, val2, temporary, TT_OP, type_of(node)));
return temporary;
case '~':
if (flag != INTERPRET_PARAMS && flag!=INTERPRET_FN_SCAN) {
/* Params should not be registered, because at this point we're not in the correct environment */
register_variable_subtree_tac(env, node, VT_ANY);
}
val1 = make_simple(env, node->left, flag, return_type);
val2 = make_simple(env, node->right, flag, return_type);
if (flag == INTERPRET_PARAMS) {
return int_param(to_string(val2), to_int(env, val1));
}
return NULL;
case 'D':
/* val1 is FN definition */
/* val1 is executed in current environment */
val1 = make_simple(env, node->left, flag, return_type);
/* New FN body environment */
new_env = create_environment(env);
if (val1!=NULL) {
/* Point function to the correct fn body */
val1->data.func->node_value = node->right;
/* Store function definition in environment */
val2 = store_function(env, val1, new_env);
}
if (flag != INTERPRET_FN_SCAN) {
/* Write out FN Name label */
append_code(make_begin_fn(val2));
append_code(make_fn_def(val2));
/* Make init frame */
temp_quad = make_init_frame();
append_code(temp_quad);
/* Define parameters with default empty values */
register_params(new_env, val2->data.func->params);
append_code(make_fn_body(val2));
/* Look inside fn body */
val2 = make_simple(new_env, node->right, EMBEDDED_FNS, val1->data.func->return_type);
/* Update prepare frame with environment size */
temp_quad->operand1 = int_value(env_size(new_env));
/* Write end of function marker */
append_code(make_end_fn(val2));
}
return NULL;
case 'd':
/* val1 is the type */
val1 = make_simple(env, node->left, flag, return_type);
/* val2 is fn name & params */
val2 = make_simple(env, node->right, flag, return_type);
/* Store return type */
val2->data.func->return_type = to_int(env, val1);
return val2;
case 'F':
/* FN name in val1 */
val1 = make_simple(env, node->left, flag, return_type);
/* Pull our parameters */
val2 = make_simple(env, node->right, INTERPRET_PARAMS, return_type);
return build_function(env, val1, val2);
case RETURN:
val1 = make_simple(env, node->left, flag, return_type);
/* Provide lookup for non-constants */
if (val1 && val1->value_type!=VT_INTEGR) {
if (val1->value_type == VT_STRING) {
val1 = get(env, val1->data.string_value);
}
else {
val1 = get(env, val1->identifier);
}
if (!val1) fatal("Undeclared identifier");
}
type_check_return(val1, return_type);
append_code(make_return(val1));
return NULL;
case ',':
val1 = make_simple(env, node->left, flag, return_type);
val2 = make_simple(env, node->right, flag, return_type);
if (val1 && val2) {
return join(val1, val2);
}
return NULL;
case APPLY:
/* FN Name */
val1 = make_simple(env, node->left, flag, return_type);
/* Params */
val2 = make_simple(env, node->right, flag, return_type);
/* Lookup function */
temp = search(env, to_string(val1), VT_FUNCTN, VT_ANY, 1);
if (temp) {
int fn_return_type;
append_code(prepare_fn(val2));
append_code(push_params(env, val2));
/* If we can't typecheck, set a special UNDEFINED flag to say we can't */
/* typecheck. This can happen with function variables, we do not EASILY know the */
/* return type of the functions they are bound to until runtime. */
fn_return_type = UNDEFINED;
if (temp->data.func) {
fn_return_type = temp->data.func->return_type;
}
/* Temporary for result (if any) */
switch(fn_return_type) {
case INT:
temporary = generate_temporary(env, int_value(0));
break;
case VOID:
temporary = generate_temporary(env, NULL);
break;
case FUNCTION:
temporary = generate_temporary(env, null_fn);
break;
default:
temporary = generate_untypechecked_temporary(env);
break;
}
append_code(make_fn_call(temporary, temp));
return temporary;
}
else {
fatal("Cannot find function '%s'", to_string(val1));
}
return NULL;
case FUNCTION:
case INT:
case VOID:
return int_value(type_of(node));
case ';':
make_simple(env, node->left, flag, return_type);
make_simple(env, node->right, flag, return_type);
return NULL;
default:
fatal("Unrecognised node type");
return NULL;
}
}