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parser.c
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parser.c
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/*
* shecc - Self-Hosting and Educational C Compiler.
*
* shecc is freely redistributable under the BSD 2 clause license. See the
* file "LICENSE" for information on usage and redistribution of this file.
*/
/* C language syntactic analyzer */
int global_var_idx = 0;
int global_label_idx = 0;
char global_str_buf[MAX_VAR_LEN];
char *gen_name()
{
sprintf(global_str_buf, ".t%d", global_var_idx++);
return global_str_buf;
}
char *gen_label()
{
sprintf(global_str_buf, ".label.%d", global_label_idx++);
return global_str_buf;
}
var_t *require_var(block_t *blk)
{
if (blk->next_local >= MAX_LOCALS)
error("Too many locals");
var_t *var = &blk->locals[blk->next_local++];
var->consumed = -1;
var->base = var;
return var;
}
/* stack of the operands of 3AC */
var_t *operand_stack[MAX_OPERAND_STACK_SIZE];
int operand_stack_idx = 0;
void opstack_push(var_t *var)
{
operand_stack[operand_stack_idx++] = var;
}
var_t *opstack_pop()
{
return operand_stack[--operand_stack_idx];
}
void read_expr(block_t *parent, basic_block_t **bb);
int write_symbol(char *data, int len)
{
int startLen = elf_data_idx;
elf_write_data_str(data, len);
return startLen;
}
int get_size(var_t *var, type_t *type)
{
if (var->is_ptr || var->is_func)
return PTR_SIZE;
return type->size;
}
int get_operator_prio(opcode_t op)
{
/* https://www.cs.uic.edu/~i109/Notes/COperatorPrecedenceTable.pdf */
switch (op) {
case OP_ternary:
return 3;
case OP_log_or:
return 4;
case OP_log_and:
return 5;
case OP_bit_or:
return 6;
case OP_bit_xor:
return 7;
case OP_bit_and:
return 8;
case OP_eq:
case OP_neq:
return 9;
case OP_lt:
case OP_leq:
case OP_gt:
case OP_geq:
return 10;
case OP_add:
case OP_sub:
return 12;
case OP_mul:
case OP_div:
case OP_mod:
return 13;
default:
return 0;
}
}
int get_unary_operator_prio(opcode_t op)
{
switch (op) {
case OP_add:
case OP_sub:
case OP_bit_not:
case OP_log_not:
return 14;
default:
return 0;
}
}
opcode_t get_operator()
{
opcode_t op = OP_generic;
if (lex_accept(T_plus))
op = OP_add;
else if (lex_accept(T_minus))
op = OP_sub;
else if (lex_accept(T_asterisk))
op = OP_mul;
else if (lex_accept(T_divide))
op = OP_div;
else if (lex_accept(T_mod))
op = OP_mod;
else if (lex_accept(T_lshift))
op = OP_lshift;
else if (lex_accept(T_rshift))
op = OP_rshift;
else if (lex_accept(T_log_and))
op = OP_log_and;
else if (lex_accept(T_log_or))
op = OP_log_or;
else if (lex_accept(T_eq))
op = OP_eq;
else if (lex_accept(T_noteq))
op = OP_neq;
else if (lex_accept(T_lt))
op = OP_lt;
else if (lex_accept(T_le))
op = OP_leq;
else if (lex_accept(T_gt))
op = OP_gt;
else if (lex_accept(T_ge))
op = OP_geq;
else if (lex_accept(T_ampersand))
op = OP_bit_and;
else if (lex_accept(T_bit_or))
op = OP_bit_or;
else if (lex_accept(T_bit_xor))
op = OP_bit_xor;
else if (lex_peek(T_question, NULL))
op = OP_ternary;
return op;
}
int read_numeric_constant(char buffer[])
{
int i = 0;
int value = 0;
while (buffer[i]) {
if (i == 1 && (buffer[i] == 'x')) { /* hexadecimal */
value = 0;
i = 2;
while (buffer[i]) {
char c = buffer[i++];
value = value << 4;
if (is_digit(c))
value += c - '0';
c |= 32; /* convert to lower case */
if (c >= 'a' && c <= 'f')
value += (c - 'a') + 10;
}
return value;
}
value = value * 10 + buffer[i++] - '0';
}
return value;
}
int read_constant_expr_operand()
{
char buffer[MAX_ID_LEN];
int value;
if (lex_peek(T_numeric, buffer)) {
lex_expect(T_numeric);
return read_numeric_constant(buffer);
}
if (lex_accept(T_open_bracket)) {
value = read_constant_expr_operand();
lex_expect(T_close_bracket);
return value;
}
if (lex_peek(T_identifier, buffer) && !strcmp(buffer, "defined")) {
char lookup_alias[MAX_TOKEN_LEN];
lex_expect(T_identifier); /* defined */
lex_expect_internal(T_open_bracket, 0);
lex_ident(T_identifier, lookup_alias);
lex_expect(T_close_bracket);
return find_alias(lookup_alias) ? 1 : 0;
}
error("Unexpected token while evaluating constant");
return -1;
}
int read_constant_infix_expr(int precedence)
{
int lhs, rhs;
/* Evaluate unary expression first */
opcode_t op = get_operator();
int current_precedence = get_unary_operator_prio(op);
if (current_precedence != 0 && current_precedence >= precedence) {
lhs = read_constant_infix_expr(current_precedence);
switch (op) {
case OP_add:
break;
case OP_sub:
lhs = lhs * -1;
break;
case OP_bit_not:
lhs = ~lhs;
break;
case OP_log_not:
lhs = !lhs;
break;
default:
error("Unexpected unary token while evaluating constant");
}
} else {
lhs = read_constant_expr_operand();
}
while (1) {
op = get_operator();
current_precedence = get_operator_prio(op);
if (current_precedence == 0 || current_precedence <= precedence) {
break;
}
rhs = read_constant_infix_expr(current_precedence);
switch (op) {
case OP_add:
lhs = lhs + rhs;
break;
case OP_sub:
lhs = lhs - rhs;
break;
case OP_mul:
lhs = lhs * rhs;
break;
case OP_div:
lhs = lhs / rhs;
break;
case OP_bit_and:
lhs = lhs & rhs;
break;
case OP_bit_or:
lhs = lhs | rhs;
break;
case OP_bit_xor:
lhs = lhs ^ rhs;
break;
case OP_lshift:
lhs = lhs << rhs;
break;
case OP_rshift:
lhs = lhs >> rhs;
break;
case OP_gt:
lhs = lhs > rhs;
break;
case OP_geq:
lhs = lhs >= rhs;
break;
case OP_lt:
lhs = lhs < rhs;
break;
case OP_leq:
lhs = lhs <= rhs;
break;
case OP_eq:
lhs = lhs == rhs;
break;
case OP_neq:
lhs = lhs != rhs;
break;
case OP_log_and:
/* TODO: Short-circuit evaluation */
lhs = lhs && rhs;
break;
case OP_log_or:
/* TODO: Short-circuit evaluation */
lhs = lhs || rhs;
break;
default:
error("Unexpected infix token while evaluating constant");
}
op = get_operator();
}
return lhs;
}
int read_constant_expr()
{
return read_constant_infix_expr(0);
}
/* Skips lines where preprocessor match is false, this will stop once next
* token is either 'T_cppd_elif', 'T_cppd_else' or 'cppd_endif'.
*/
void cppd_control_flow_skip_lines()
{
while (!lex_peek(T_cppd_elif, NULL) && !lex_peek(T_cppd_else, NULL) &&
!lex_peek(T_cppd_endif, NULL)) {
next_token = lex_token();
}
skip_whitespace();
}
void check_def(char *alias)
{
if (find_alias(alias))
preproc_match = 1;
}
void read_defined_macro()
{
char lookup_alias[MAX_TOKEN_LEN];
lex_expect(T_identifier); /* defined */
lex_expect_internal(T_open_bracket, 0);
lex_ident(T_identifier, lookup_alias);
lex_expect(T_close_bracket);
check_def(lookup_alias);
}
/* read preprocessor directive at each potential positions: e.g.,
* global statement / body statement
*/
int read_preproc_directive()
{
char token[MAX_ID_LEN];
if (lex_peek(T_cppd_include, token)) {
lex_expect(T_cppd_include);
/* Basic #define syntax validation */
if (lex_peek(T_string, NULL)) {
/* #define "header.h" */
lex_expect(T_string);
} else {
/* #define <stdlib.h> */
lex_expect(T_lt);
while (!lex_peek(T_gt, NULL)) {
next_token = lex_token();
}
lex_expect(T_gt);
}
return 1;
}
if (lex_accept(T_cppd_define)) {
char alias[MAX_VAR_LEN];
char value[MAX_VAR_LEN];
lex_ident(T_identifier, alias);
if (lex_peek(T_numeric, value)) {
lex_expect(T_numeric);
add_alias(alias, value);
} else if (lex_peek(T_string, value)) {
lex_expect(T_string);
add_alias(alias, value);
} else if (lex_peek(T_identifier, value)) {
lex_expect(T_identifier);
add_alias(alias, value);
} else if (lex_accept(T_open_bracket)) { /* function-like macro */
macro_t *macro = add_macro(alias);
skip_newline = 0;
while (lex_peek(T_identifier, alias)) {
lex_expect(T_identifier);
strcpy(macro->param_defs[macro->num_param_defs++].var_name,
alias);
lex_accept(T_comma);
}
if (lex_accept(T_elipsis))
macro->is_variadic = 1;
macro->start_source_idx = source_idx;
skip_macro_body();
}
return 1;
}
if (lex_peek(T_cppd_undef, token)) {
char alias[MAX_VAR_LEN];
lex_expect_internal(T_cppd_undef, 0);
lex_peek(T_identifier, alias);
lex_expect(T_identifier);
remove_alias(alias);
remove_macro(alias);
return 1;
}
if (lex_peek(T_cppd_error, NULL)) {
int i = 0;
char error_diagnostic[MAX_LINE_LEN];
do {
error_diagnostic[i++] = next_char;
} while (read_char(0) != '\n');
error_diagnostic[i] = 0;
error(error_diagnostic);
}
if (lex_accept(T_cppd_if)) {
preproc_match = read_constant_expr() != 0;
if (preproc_match) {
skip_whitespace();
} else {
cppd_control_flow_skip_lines();
}
return 1;
}
if (lex_accept(T_cppd_elif)) {
if (preproc_match) {
while (!lex_peek(T_cppd_endif, NULL)) {
next_token = lex_token();
}
return 1;
}
preproc_match = read_constant_expr() != 0;
if (preproc_match) {
skip_whitespace();
} else {
cppd_control_flow_skip_lines();
}
return 1;
}
if (lex_accept(T_cppd_else)) {
/* reach here has 2 possible cases:
* 1. reach #ifdef preprocessor directive
* 2. conditional expression in #elif is false
*/
if (!preproc_match) {
skip_whitespace();
return 1;
}
cppd_control_flow_skip_lines();
return 1;
}
if (lex_accept(T_cppd_endif)) {
preproc_match = 0;
skip_whitespace();
return 1;
}
if (lex_accept_internal(T_cppd_ifdef, 0)) {
preproc_match = 0;
lex_ident(T_identifier, token);
check_def(token);
if (preproc_match) {
skip_whitespace();
return 1;
}
cppd_control_flow_skip_lines();
return 1;
}
return 0;
}
void read_parameter_list_decl(func_t *fd, int anon);
void read_inner_var_decl(var_t *vd, int anon, int is_param)
{
vd->init_val = 0;
vd->is_ptr = 0;
while (lex_accept(T_asterisk))
vd->is_ptr++;
/* is it function pointer declaration? */
if (lex_accept(T_open_bracket)) {
func_t func;
lex_expect(T_asterisk);
lex_ident(T_identifier, vd->var_name);
lex_expect(T_close_bracket);
read_parameter_list_decl(&func, 1);
vd->is_func = 1;
} else {
if (anon == 0) {
lex_ident(T_identifier, vd->var_name);
if (!lex_peek(T_open_bracket, NULL) && !is_param) {
if (vd->is_global) {
ph1_ir_t *ir = add_global_ir(OP_allocat);
ir->src0 = vd;
opstack_push(vd);
} else {
ph1_ir_t *ph1_ir;
ph1_ir = add_ph1_ir(OP_allocat);
ph1_ir->src0 = vd;
}
}
}
if (lex_accept(T_open_square)) {
char buffer[10];
/* array with size */
if (lex_peek(T_numeric, buffer)) {
vd->array_size = read_numeric_constant(buffer);
lex_expect(T_numeric);
} else {
/* array without size:
* regarded as a pointer although could be nested
*/
vd->is_ptr++;
}
lex_expect(T_close_square);
} else {
vd->array_size = 0;
}
vd->is_func = 0;
}
}
/* starting next_token, need to check the type */
void read_full_var_decl(var_t *vd, int anon, int is_param)
{
lex_accept(T_struct); /* ignore struct definition */
lex_ident(T_identifier, vd->type_name);
read_inner_var_decl(vd, anon, is_param);
}
/* starting next_token, need to check the type */
void read_partial_var_decl(var_t *vd, var_t *template)
{
strcpy(vd->type_name, template->type_name);
read_inner_var_decl(vd, 0, 0);
}
void read_parameter_list_decl(func_t *fd, int anon)
{
int vn = 0;
lex_expect(T_open_bracket);
while (lex_peek(T_identifier, NULL) == 1) {
read_full_var_decl(&fd->param_defs[vn++], anon, 1);
lex_accept(T_comma);
}
fd->num_params = vn;
/* Up to 'MAX_PARAMS' parameters are accepted for the variadic function. */
if (lex_accept(T_elipsis))
fd->va_args = 1;
lex_expect(T_close_bracket);
}
void read_literal_param(block_t *parent, basic_block_t *bb)
{
char literal[MAX_TOKEN_LEN];
lex_ident(T_string, literal);
int index = write_symbol(literal, strlen(literal) + 1);
ph1_ir_t *ph1_ir = add_ph1_ir(OP_load_data_address);
var_t *vd = require_var(parent);
strcpy(vd->var_name, gen_name());
vd->init_val = index;
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, bb, OP_load_data_address, ph1_ir->dest, NULL, NULL, 0,
NULL);
}
void read_numeric_param(block_t *parent, basic_block_t *bb, int is_neg)
{
char token[MAX_ID_LEN];
int value = 0;
int i = 0;
char c;
lex_ident(T_numeric, token);
if (token[0] == '-') {
is_neg = 1 - is_neg;
i++;
}
if ((token[0] == '0') && (token[1] == 'x')) { /* hexadecimal */
i = 2;
do {
c = token[i++];
if (is_digit(c))
c -= '0';
else {
c |= 32; /* convert to lower case */
if (c >= 'a' && c <= 'f')
c = (c - 'a') + 10;
else
error("Invalid numeric constant");
}
value = (value * 16) + c;
} while (is_hex(token[i]));
} else {
do {
c = token[i++] - '0';
value = (value * 10) + c;
} while (is_digit(token[i]));
}
if (is_neg)
value = -value;
ph1_ir_t *ph1_ir = add_ph1_ir(OP_load_constant);
var_t *vd = require_var(parent);
vd->init_val = value;
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, bb, OP_load_constant, ph1_ir->dest, NULL, NULL, 0, NULL);
}
void read_char_param(block_t *parent, basic_block_t *bb)
{
char token[5];
lex_ident(T_char, token);
ph1_ir_t *ph1_ir = add_ph1_ir(OP_load_constant);
var_t *vd = require_var(parent);
vd->init_val = token[0];
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, bb, OP_load_constant, ph1_ir->dest, NULL, NULL, 0, NULL);
}
void read_ternary_operation(block_t *parent, basic_block_t **bb);
void read_func_parameters(block_t *parent, basic_block_t **bb)
{
int param_num = 0;
var_t *params[MAX_PARAMS];
lex_expect(T_open_bracket);
while (!lex_accept(T_close_bracket)) {
read_expr(parent, bb);
read_ternary_operation(parent, bb);
params[param_num++] = opstack_pop();
lex_accept(T_comma);
}
for (int i = 0; i < param_num; i++) {
ph1_ir_t *ph1_ir = add_ph1_ir(OP_push);
ph1_ir->src0 = params[i];
/* The operand should keep alive before calling function. Pass the
* number of remained parameters to allocator to extend their liveness.
*/
add_insn(parent, *bb, OP_push, NULL, ph1_ir->src0, NULL, param_num - i,
NULL);
}
}
void read_func_call(func_t *fn, block_t *parent, basic_block_t **bb)
{
/* direct function call */
read_func_parameters(parent, bb);
ph1_ir_t *ph1_ir = add_ph1_ir(OP_call);
ph1_ir->param_num = fn->num_params;
strcpy(ph1_ir->func_name, fn->return_def.var_name);
add_insn(parent, *bb, OP_call, NULL, NULL, NULL, 0,
fn->return_def.var_name);
}
void read_indirect_call(block_t *parent, basic_block_t **bb)
{
read_func_parameters(parent, bb);
ph1_ir_t *ph1_ir = add_ph1_ir(OP_indirect);
ph1_ir->src0 = opstack_pop();
add_insn(parent, *bb, OP_indirect, NULL, ph1_ir->src0, NULL, 0, NULL);
}
ph1_ir_t side_effect[10];
int se_idx = 0;
void read_lvalue(lvalue_t *lvalue,
var_t *var,
block_t *parent,
basic_block_t **bb,
int eval,
opcode_t op);
/* Maintain a stack of expression values and operators, depending on next
* operators' priority. Either apply it or operator on stack first.
*/
void read_expr_operand(block_t *parent, basic_block_t **bb)
{
ph1_ir_t *ph1_ir;
var_t *vd;
int is_neg = 0;
if (lex_accept(T_minus)) {
is_neg = 1;
if (lex_peek(T_numeric, NULL) == 0 &&
lex_peek(T_identifier, NULL) == 0 &&
lex_peek(T_open_bracket, NULL) == 0) {
error("Unexpected token after unary minus");
}
}
if (lex_peek(T_string, NULL))
read_literal_param(parent, *bb);
else if (lex_peek(T_char, NULL))
read_char_param(parent, *bb);
else if (lex_peek(T_numeric, NULL))
read_numeric_param(parent, *bb, is_neg);
else if (lex_accept(T_log_not)) {
read_expr_operand(parent, bb);
ph1_ir = add_ph1_ir(OP_log_not);
ph1_ir->src0 = opstack_pop();
vd = require_var(parent);
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, *bb, OP_log_not, ph1_ir->dest, ph1_ir->src0, NULL, 0,
NULL);
} else if (lex_accept(T_bit_not)) {
read_expr_operand(parent, bb);
ph1_ir = add_ph1_ir(OP_bit_not);
ph1_ir->src0 = opstack_pop();
vd = require_var(parent);
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, *bb, OP_bit_not, ph1_ir->dest, ph1_ir->src0, NULL, 0,
NULL);
} else if (lex_accept(T_ampersand)) {
char token[MAX_VAR_LEN];
lvalue_t lvalue;
lex_peek(T_identifier, token);
var_t *var = find_var(token, parent);
read_lvalue(&lvalue, var, parent, bb, 0, OP_generic);
if (lvalue.is_reference == 0) {
ph1_ir = add_ph1_ir(OP_address_of);
ph1_ir->src0 = opstack_pop();
vd = require_var(parent);
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, *bb, OP_address_of, ph1_ir->dest, ph1_ir->src0,
NULL, 0, NULL);
}
} else if (lex_accept(T_asterisk)) {
/* dereference */
char token[MAX_VAR_LEN];
lvalue_t lvalue;
int open_bracket = lex_accept(T_open_bracket);
lex_peek(T_identifier, token);
var_t *var = find_var(token, parent);
read_lvalue(&lvalue, var, parent, bb, 1, OP_generic);
if (open_bracket)
lex_expect(T_close_bracket);
ph1_ir = add_ph1_ir(OP_read);
ph1_ir->src0 = opstack_pop();
vd = require_var(parent);
if (lvalue.is_ptr > 1)
ph1_ir->size = PTR_SIZE;
else
ph1_ir->size = lvalue.type->size;
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, *bb, OP_read, ph1_ir->dest, ph1_ir->src0, ph1_ir->src1,
ph1_ir->size, NULL);
} else if (lex_accept(T_open_bracket)) {
read_expr(parent, bb);
read_ternary_operation(parent, bb);
lex_expect(T_close_bracket);
} else if (lex_accept(T_sizeof)) {
char token[MAX_TYPE_LEN];
lex_expect(T_open_bracket);
int find_type_flag = lex_accept(T_struct) ? 2 : 1;
lex_ident(T_identifier, token);
type_t *type = find_type(token, find_type_flag);
if (!type)
error("Unable to find type");
ph1_ir = add_ph1_ir(OP_load_constant);
vd = require_var(parent);
vd->init_val = type->size;
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
lex_expect(T_close_bracket);
add_insn(parent, *bb, OP_load_constant, ph1_ir->dest, NULL, NULL, 0,
NULL);
} else {
/* function call, constant or variable - read token and determine */
opcode_t prefix_op = OP_generic;
char token[MAX_ID_LEN];
if (lex_accept(T_increment))
prefix_op = OP_add;
else if (lex_accept(T_decrement))
prefix_op = OP_sub;
lex_peek(T_identifier, token);
/* is a constant or variable? */
constant_t *con = find_constant(token);
var_t *var = find_var(token, parent);
func_t *fn = find_func(token);
int macro_param_idx = find_macro_param_src_idx(token, parent);
macro_t *mac = find_macro(token);
if (!strcmp(token, "__VA_ARGS__")) {
/* 'source_idx' has pointed at the character after __VA_ARGS__ */
int remainder, t = source_idx;
macro_t *macro = parent->macro;
if (!macro)
error("The '__VA_ARGS__' identifier can only be used in macro");
if (!macro->is_variadic)
error("Unexpected identifier '__VA_ARGS__'");
remainder = macro->num_params - macro->num_param_defs;
for (int i = 0; i < remainder; i++) {
source_idx = macro->params[macro->num_params - remainder + i];
next_char = SOURCE[source_idx];
next_token = lex_token();
read_expr(parent, bb);
}
source_idx = t;
next_char = SOURCE[source_idx];
next_token = lex_token();
} else if (mac) {
if (parent->macro)
error("Nested macro is not yet supported");
parent->macro = mac;
mac->num_params = 0;
lex_expect(T_identifier);
/* 'source_idx' has pointed at the first parameter */
while (!lex_peek(T_close_bracket, NULL)) {
mac->params[mac->num_params++] = source_idx;
do {
next_token = lex_token();
} while (next_token != T_comma &&
next_token != T_close_bracket);
}
/* move 'source_idx' to the macro body */
macro_return_idx = source_idx;
source_idx = mac->start_source_idx;
next_char = SOURCE[source_idx];
lex_expect(T_close_bracket);
skip_newline = 0;
read_expr(parent, bb);
/* cleanup */
skip_newline = 1;
parent->macro = NULL;
macro_return_idx = 0;
} else if (macro_param_idx) {
/* "expand" the argument from where it comes from */
int t = source_idx;
source_idx = macro_param_idx;
next_char = SOURCE[source_idx];
next_token = lex_token();
read_expr(parent, bb);
source_idx = t;
next_char = SOURCE[source_idx];
next_token = lex_token();
} else if (con) {
ph1_ir = add_ph1_ir(OP_load_constant);
vd = require_var(parent);
vd->init_val = con->value;
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
lex_expect(T_identifier);
add_insn(parent, *bb, OP_load_constant, ph1_ir->dest, NULL, NULL, 0,
NULL);
} else if (var) {
/* evalue lvalue expression */
lvalue_t lvalue;
read_lvalue(&lvalue, var, parent, bb, 1, prefix_op);
/* is it an indirect call with function pointer? */
if (lex_peek(T_open_bracket, NULL)) {
read_indirect_call(parent, bb);
ph1_ir = add_ph1_ir(OP_func_ret);
vd = require_var(parent);
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, *bb, OP_func_ret, ph1_ir->dest, NULL, NULL, 0,
NULL);
}
} else if (fn) {
lex_expect(T_identifier);
if (lex_peek(T_open_bracket, NULL)) {
read_func_call(fn, parent, bb);
ph1_ir = add_ph1_ir(OP_func_ret);
vd = require_var(parent);
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, *bb, OP_func_ret, ph1_ir->dest, NULL, NULL, 0,
NULL);
} else {
/* indirective function pointer assignment */
vd = require_var(parent);
vd->is_func = 1;
strcpy(vd->var_name, token);
opstack_push(vd);
}
} else {
printf("%s\n", token);
/* unknown expression */
error("Unrecognized expression token");
}
if (is_neg) {
ph1_ir = add_ph1_ir(OP_negate);
ph1_ir->src0 = opstack_pop();
vd = require_var(parent);
strcpy(vd->var_name, gen_name());
ph1_ir->dest = vd;
opstack_push(vd);
add_insn(parent, *bb, OP_negate, ph1_ir->dest, ph1_ir->src0, NULL,
0, NULL);
}
}
}
void read_expr(block_t *parent, basic_block_t **bb)
{
ph1_ir_t *ph1_ir;
var_t *vd;
opcode_t oper_stack[10];
int oper_stack_idx = 0;
read_expr_operand(parent, bb);
opcode_t op = get_operator();
if (op == OP_generic || op == OP_ternary)
return;
oper_stack[oper_stack_idx++] = op;
read_expr_operand(parent, bb);
op = get_operator();
while (op != OP_generic && op != OP_ternary) {
if (oper_stack_idx > 0) {
int same = 0;
do {
opcode_t top_op = oper_stack[oper_stack_idx - 1];
if (get_operator_prio(top_op) >= get_operator_prio(op)) {
ph1_ir = add_ph1_ir(top_op);
ph1_ir->src1 = opstack_pop();