Correctly handle JMP and RET IL operators in flow control analysis.
--- a/stage3/flow_control_analysis.cc Sat Mar 03 13:07:00 2012 +0000
+++ b/stage3/flow_control_analysis.cc Sat Mar 03 20:27:20 2012 +0000
@@ -180,6 +180,7 @@
/*| 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];
@@ -194,10 +195,11 @@
// 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)
+ if ((NULL != prev_il_instruction) && (!prev_il_instruction_is_JMP_or_RET))
symbol->prev_il_instruction.push_back(prev_il_instruction);
- /* check if it is an il_expression_c, or a JMP[C[N]] and if so, handle it correctly */
+ /* 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;
@@ -238,7 +240,8 @@
/* search for the il_instruction_c containing the label */
il_instruction_c *destination = search_il_label->find_label(symbol->label);
- /* TODO: for JMP and RET (unconditional) instructions, make sure the next IL instruction does not point back! */
+ /* give the visit(JMP_operator *) an oportunity to set the prev_il_instruction_is_JMP_or_RET flag! */
+ symbol->il_jump_operator->accept(*this);
/* add, to that il_instruction's list of prev_il_intsructions, the curr_il_instruction */
if (NULL != destination)
destination->prev_il_instruction.push_back(curr_il_instruction);
@@ -330,10 +333,22 @@
// void *visit( CAL_operator_c *symbol);
// void *visit( CALC_operator_c *symbol);
// void *visit(CALCN_operator_c *symbol);
-// void *visit( RET_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);
-// void *visit( JMP_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);
--- a/stage3/flow_control_analysis.hh Sat Mar 03 13:07:00 2012 +0000
+++ b/stage3/flow_control_analysis.hh Sat Mar 03 20:27:20 2012 +0000
@@ -51,6 +51,7 @@
search_il_label_c *search_il_label;
symbol_c *prev_il_instruction;
symbol_c *curr_il_instruction;
+ bool prev_il_instruction_is_JMP_or_RET;
public:
flow_control_analysis_c(symbol_c *ignore);
@@ -138,10 +139,10 @@
// void *visit( CAL_operator_c *symbol);
// void *visit( CALC_operator_c *symbol);
// void *visit(CALCN_operator_c *symbol);
-// void *visit( RET_operator_c *symbol);
+ void *visit( RET_operator_c *symbol);
// void *visit( RETC_operator_c *symbol);
// void *visit(RETCN_operator_c *symbol);
-// void *visit( JMP_operator_c *symbol);
+ void *visit( JMP_operator_c *symbol);
// void *visit( JMPC_operator_c *symbol);
// void *visit(JMPCN_operator_c *symbol);