/*
* matiec - a compiler for the programming languages defined in IEC 61131-3
*
* Copyright (C) 2012 Mario de Sousa (msousa@fe.up.pt)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* This code is made available on the understanding that it will not be
* used in safety-critical situations without a full and competent review.
*/
/*
* An IEC 61131-3 compiler.
*
* Based on the
* FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
*
*/
/*
* Do flow control analysis of the IEC 61131-3 code.
*
* We currently only do this for IL code.
* This class will annotate the abstract syntax tree, by filling in the
* prev_il_instruction variable in the il_instruction_c, so it points to
* the previous il_instruction_c object in the instruction list instruction_list_c.
*
* Since IL code can contain jumps (JMP), the same il_instruction may effectively have
* several previous il_instructions. In order to accommodate this, each il_instruction
* will maintain a vector (i..e an array) of pointers to all the previous il_instructions.
* We do however attempt to guarantee that the first element in the vector (array) will preferentially
* point to the il instruction that is right before / imediately preceding the current il instructions,
* i.e. the first element in the array will tend to point to the previous il_instruction
* that is not a jump JMP IL instruction!
*
* The result will essentially be a graph of il_instruction_c objects, each
* pointing to the previous il_instruction_c object.
*
* The reality is we will get several independent and isolated linked lists
* (actually, since we now process labels correctly, this is really a graph):
* one for each block of IL code (e.g. inside a Function, FB or Program).
* Additionally, when the IL code has an expression (expression_c object), we will actually
* have one more isolated linked list for the IL code inside that expression.
*
* e.g.
* line_1: LD 1
* line_2: ADD (42
* line_3: ADD B
* line_4: ADD C
* line_5: )
* line_6: ADD D
* line_7: ST E
*
* will result in two independent linked lists:
* main list: line_7 -> line_6 -> line2 -> line_1
* expr list: lin4_4 -> line_3 -> (operand of line_2, i.e. '42')
*
*
* In the main list, each:
* line_x: IL_operation IL_operand
* is encoded as
* il_instruction_c(label, il_incomplete_instruction)
* these il_instruction_c objects will point back to the previous il_instruction_c object.
*
* In the expr list, each
* line_x: IL_operation IL_operand
* is encoded as
* il_simple_instruction_c(il_simple_instruction)
* these il_simple_instruction_c objects will point back to the previous il_simple_instruction_c object,
* except the for the first il_simple_instruction_c object in the list, which will point back to
* the first il_operand (in the above example, '42'), or NULL is it does not exist.
*
*
* label:
* identifier_c
*
* il_incomplete_instruction:
* il_simple_operation (il_simple_operation_c, il_function_call_c)
* | il_expression (il_expression_c)
* | il_jump_operation (il_jump_operation_c)
* | il_fb_call (il_fb_call_c)
* | il_formal_funct_call (il_formal_funct_call_c)
* | il_return_operator (RET_operator_c, RETC_operator_c, RETCN_operator_c)
*
*
* il_expression_c(il_expr_operator, il_operand, simple_instr_list)
*
* il_operand:
* variable (symbolic_variable_c, direct_variable_c, array_variable_c, structured_variable_c)
* | enumerated_value (enumerated_value_c)
* | constant (lots of literal classes _c)
*
* simple_instr_list:
* list of il_simple_instruction
*
* il_simple_instruction:
* il_simple_operation (il_simple_operation_c, il_function_call_c)
* | il_expression (il_expression_c)
* | il_formal_funct_call (il_formal_funct_call_c)
*
*/
#include "flow_control_analysis.hh"
/* set to 1 to see debug info during execution */
static int debug = 0;
flow_control_analysis_c::flow_control_analysis_c(symbol_c *ignore) {
prev_il_instruction = NULL;
curr_il_instruction = NULL;
prev_il_instruction_is_JMP_or_RET = false;
search_il_label = NULL;
}
flow_control_analysis_c::~flow_control_analysis_c(void) {
}
void flow_control_analysis_c::link_insert(symbol_c *prev_instruction, symbol_c *next_instruction) {
il_instruction_c *next_a = dynamic_cast<il_instruction_c *>(next_instruction);
il_instruction_c *prev_a = dynamic_cast<il_instruction_c *>(prev_instruction);
il_simple_instruction_c *next_b = dynamic_cast<il_simple_instruction_c *>(next_instruction);
il_simple_instruction_c *prev_b = dynamic_cast<il_simple_instruction_c *>(prev_instruction);
if (NULL != next_a) next_a->prev_il_instruction.insert(next_a->prev_il_instruction.begin(), prev_instruction);
else if (NULL != next_b) next_b->prev_il_instruction.insert(next_b->prev_il_instruction.begin(), prev_instruction);
else ERROR;
if (NULL != prev_a) prev_a->next_il_instruction.insert(prev_a->next_il_instruction.begin(), next_instruction);
else if (NULL != prev_b) prev_b->next_il_instruction.insert(prev_b->next_il_instruction.begin(), next_instruction);
else ERROR;
}
void flow_control_analysis_c::link_pushback(symbol_c *prev_instruction, symbol_c *next_instruction) {
il_instruction_c *next = dynamic_cast<il_instruction_c *>(next_instruction);
il_instruction_c *prev = dynamic_cast<il_instruction_c *>(prev_instruction);
if ((NULL == next) || (NULL == prev)) ERROR;
next->prev_il_instruction.push_back(prev);
prev->next_il_instruction.push_back(next);
}
/************************************/
/* B 1.5 Program organization units */
/************************************/
/*********************/
/* B 1.5.1 Functions */
/*********************/
void *flow_control_analysis_c::visit(function_declaration_c *symbol) {
search_il_label = new search_il_label_c(symbol);
if (debug) printf("Doing flow control analysis in body of function %s\n", ((token_c *)(symbol->derived_function_name))->value);
symbol->function_body->accept(*this);
delete search_il_label;
search_il_label = NULL;
return NULL;
}
/***************************/
/* B 1.5.2 Function blocks */
/***************************/
void *flow_control_analysis_c::visit(function_block_declaration_c *symbol) {
search_il_label = new search_il_label_c(symbol);
if (debug) printf("Doing flow control analysis in body of FB %s\n", ((token_c *)(symbol->fblock_name))->value);
symbol->fblock_body->accept(*this);
delete search_il_label;
search_il_label = NULL;
return NULL;
}
/********************/
/* B 1.5.3 Programs */
/********************/
void *flow_control_analysis_c::visit(program_declaration_c *symbol) {
search_il_label = new search_il_label_c(symbol);
if (debug) printf("Doing flow control analysis in body of program %s\n", ((token_c *)(symbol->program_type_name))->value);
symbol->function_block_body->accept(*this);
delete search_il_label;
search_il_label = NULL;
return NULL;
}
/********************************/
/* B 1.7 Configuration elements */
/********************************/
void *flow_control_analysis_c::visit(configuration_declaration_c *symbol) {
return NULL;
}
/****************************************/
/* B.2 - Language IL (Instruction List) */
/****************************************/
/***********************************/
/* B 2.1 Instructions and Operands */
/***********************************/
/*| instruction_list il_instruction */
// SYM_LIST(instruction_list_c)
void *flow_control_analysis_c::visit(instruction_list_c *symbol) {
prev_il_instruction_is_JMP_or_RET = false;
for(int i = 0; i < symbol->n; i++) {
prev_il_instruction = NULL;
if (i > 0) prev_il_instruction = symbol->elements[i-1];
curr_il_instruction = symbol->elements[i];
curr_il_instruction->accept(*this);
curr_il_instruction = NULL;
}
return NULL;
}
/* | label ':' [il_incomplete_instruction] eol_list */
// SYM_REF2(il_instruction_c, label, il_instruction)
// void *visit(instruction_list_c *symbol);
void *flow_control_analysis_c::visit(il_instruction_c *symbol) {
if ((NULL != prev_il_instruction) && (!prev_il_instruction_is_JMP_or_RET))
/* We try to guarantee that the previous il instruction that is in the previous line, will occupy the first element of the vector.
* In order to do that, we use insert() instead of push_back()
*/
link_insert(prev_il_instruction, symbol);
/* check if it is an il_expression_c, a JMP[C[N]], or a RET, and if so, handle it correctly */
prev_il_instruction_is_JMP_or_RET = false;
if (NULL != symbol->il_instruction)
symbol->il_instruction->accept(*this);
return NULL;
}
/* | il_simple_operator [il_operand] */
// SYM_REF2(il_simple_operation_c, il_simple_operator, il_operand)
// void *flow_control_analysis_c::visit(il_simple_operation_c *symbol)
/* | function_name [il_operand_list] */
/* NOTE: The parameters 'called_function_declaration' and 'extensible_param_count' are used to pass data between the stage 3 and stage 4. */
// SYM_REF2(il_function_call_c, function_name, il_operand_list, symbol_c *called_function_declaration; int extensible_param_count;)
// void *flow_control_analysis_c::visit(il_function_call_c *symbol)
/* | il_expr_operator '(' [il_operand] eol_list [simple_instr_list] ')' */
// SYM_REF3(il_expression_c, il_expr_operator, il_operand, simple_instr_list);
void *flow_control_analysis_c::visit(il_expression_c *symbol) {
if(NULL == symbol->simple_instr_list)
/* nothing to do... */
return NULL;
symbol_c *save_prev_il_instruction = prev_il_instruction;
/* Stage2 will insert an artificial (and equivalent) LD <il_operand> to the simple_instr_list if necessary. We can therefore ignore the 'il_operand' entry! */
// prev_il_instruction = symbol->il_operand;
prev_il_instruction = NULL;
symbol->simple_instr_list->accept(*this);
prev_il_instruction = save_prev_il_instruction;
return NULL;
}
/* il_jump_operator label */
// SYM_REF2(il_jump_operation_c, il_jump_operator, label)
void *flow_control_analysis_c::visit(il_jump_operation_c *symbol) {
/* search for the il_instruction_c containing the label */
il_instruction_c *destination = search_il_label->find_label(symbol->label);
/* give the visit(JMP_operator *) an oportunity to set the prev_il_instruction_is_JMP_or_RET flag! */
symbol->il_jump_operator->accept(*this);
if (NULL != destination)
link_pushback(curr_il_instruction, destination);
return NULL;
}
/* il_call_operator prev_declared_fb_name
* | il_call_operator prev_declared_fb_name '(' ')'
* | il_call_operator prev_declared_fb_name '(' eol_list ')'
* | il_call_operator prev_declared_fb_name '(' il_operand_list ')'
* | il_call_operator prev_declared_fb_name '(' eol_list il_param_list ')'
*/
/* NOTE: The parameter 'called_fb_declaration'is used to pass data between stage 3 and stage4 (although currently it is not used in stage 4 */
// SYM_REF4(il_fb_call_c, il_call_operator, fb_name, il_operand_list, il_param_list, symbol_c *called_fb_declaration)
// void *flow_control_analysis_c::visit(il_fb_call_c *symbol)
/* | function_name '(' eol_list [il_param_list] ')' */
/* NOTE: The parameter 'called_function_declaration' is used to pass data between the stage 3 and stage 4. */
// SYM_REF2(il_formal_funct_call_c, function_name, il_param_list, symbol_c *called_function_declaration; int extensible_param_count;)
// void *flow_control_analysis_c::visit(il_formal_funct_call_c *symbol)
// void *visit(il_operand_list_c *symbol);
void *flow_control_analysis_c::visit(simple_instr_list_c *symbol) {
for(int i = 0; i < symbol->n; i++) {
/* The prev_il_instruction for element[0] was set in visit(il_expression_c *) */
if (i>0) prev_il_instruction = symbol->elements[i-1];
symbol->elements[i]->accept(*this);
}
return NULL;
}
// SYM_REF1(il_simple_instruction_c, il_simple_instruction, symbol_c *prev_il_instruction;)
void *flow_control_analysis_c::visit(il_simple_instruction_c*symbol) {
if (NULL != prev_il_instruction)
/* We try to guarantee that the previous il instruction that is in the previous line, will occupy the first element of the vector.
* In order to do that, we use insert() instead of push_back()
*/
link_insert(prev_il_instruction, symbol);
return NULL;
}
/*
void *visit(il_param_list_c *symbol);
void *visit(il_param_assignment_c *symbol);
void *visit(il_param_out_assignment_c *symbol);
*/
/*******************/
/* B 2.2 Operators */
/*******************/
// void *visit( LD_operator_c *symbol);
// void *visit( LDN_operator_c *symbol);
// void *visit( ST_operator_c *symbol);
// void *visit( STN_operator_c *symbol);
// void *visit( NOT_operator_c *symbol);
// void *visit( S_operator_c *symbol);
// void *visit( R_operator_c *symbol);
// void *visit( S1_operator_c *symbol);
// void *visit( R1_operator_c *symbol);
// void *visit( CLK_operator_c *symbol);
// void *visit( CU_operator_c *symbol);
// void *visit( CD_operator_c *symbol);
// void *visit( PV_operator_c *symbol);
// void *visit( IN_operator_c *symbol);
// void *visit( PT_operator_c *symbol);
// void *visit( AND_operator_c *symbol);
// void *visit( OR_operator_c *symbol);
// void *visit( XOR_operator_c *symbol);
// void *visit( ANDN_operator_c *symbol);
// void *visit( ORN_operator_c *symbol);
// void *visit( XORN_operator_c *symbol);
// void *visit( ADD_operator_c *symbol);
// void *visit( SUB_operator_c *symbol);
// void *visit( MUL_operator_c *symbol);
// void *visit( DIV_operator_c *symbol);
// void *visit( MOD_operator_c *symbol);
// void *visit( GT_operator_c *symbol);
// void *visit( GE_operator_c *symbol);
// void *visit( EQ_operator_c *symbol);
// void *visit( LT_operator_c *symbol);
// void *visit( LE_operator_c *symbol);
// void *visit( NE_operator_c *symbol);
// void *visit( CAL_operator_c *symbol);
// void *visit( CALC_operator_c *symbol);
// void *visit(CALCN_operator_c *symbol);
/* this next visit function will be called directly from visit(il_instruction_c *) */
void *flow_control_analysis_c::visit( RET_operator_c *symbol) {
prev_il_instruction_is_JMP_or_RET = true;
return NULL;
}
// void *visit( RETC_operator_c *symbol);
// void *visit(RETCN_operator_c *symbol);
/* this next visit function will be called from visit(il_jump_operation_c *) */
void *flow_control_analysis_c::visit( JMP_operator_c *symbol) {
prev_il_instruction_is_JMP_or_RET = true;
return NULL;
}
// void *visit( JMPC_operator_c *symbol);
// void *visit(JMPCN_operator_c *symbol);
/* Symbol class handled together with function call checks */
// void *visit(il_assign_operator_c *symbol, variable_name);
/* Symbol class handled together with function call checks */
// void *visit(il_assign_operator_c *symbol, option, variable_name);