special handling of unions when doing effect analysis

1) recognize the fact that write to one field of an union is in conflict with read/write to another field. This is in contrast with structures. 2) print out statistics of how many union variables are generated at the end of the program 3) clean up statistics collecting a little
csmith-project · Jun 10, 2011 · 4cb9161 · 4cb9161
1 parent e7e4945
commit 4cb9161
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diff --git a/src/Bookkeeper.cpp b/src/Bookkeeper.cpp
@@ -51,7 +51,7 @@ using namespace std;
 
 // counter for all levels of struct depth
 std::vector<int> Bookkeeper::struct_depth_cnts; 
-
+int Bookkeeper::union_var_cnt = 0;
 std::vector<int> Bookkeeper::expr_depth_cnts;
 std::vector<int> Bookkeeper::dereference_level_cnts;
 int Bookkeeper::address_taken_cnt = 0;
@@ -136,7 +136,7 @@ Bookkeeper::output_stmts_statistics(std::ostream &out)
 void
 Bookkeeper::output_statistics(std::ostream &out)
 {
-	output_struct_statistics(out);
+	output_struct_union_statistics(out);
 	out << endl;
 	output_expr_statistics(out);
 	out << endl;
@@ -152,13 +152,14 @@ Bookkeeper::output_statistics(std::ostream &out)
 }
 
 void
-Bookkeeper::output_struct_statistics(std::ostream &out)
+Bookkeeper::output_struct_union_statistics(std::ostream &out)
 {
 	formated_output(out, "max struct depth: ", (struct_depth_cnts.size()-1));
 	out << "breakdown:" << endl;
 	for (size_t i=0; i<struct_depth_cnts.size(); i++) {
 		out << "   depth: " << i << ", occurrence: " << struct_depth_cnts[i] << endl;
 	}
+	formated_output(out, "total union variables: ", union_var_cnt);
 	Bookkeeper::output_bitfields(out);
 }
 

diff --git a/src/Bookkeeper.h b/src/Bookkeeper.h
@@ -50,7 +50,7 @@ class Bookkeeper
 
 	static void output_statistics(std::ostream &out);
 
-	static void output_struct_statistics(std::ostream &out);
+	static void output_struct_union_statistics(std::ostream &out);
 
 	static void output_expr_statistics(std::ostream &out);
 
@@ -85,7 +85,9 @@ class Bookkeeper
 
 	static void output_var_freshness(std::ostream &out);
 
-	static std::vector<int> struct_depth_cnts;  
+	static std::vector<int> struct_depth_cnts; 
+
+	static int union_var_cnt; 
 
 	static std::vector<int> expr_depth_cnts;
 

diff --git a/src/CGContext.cpp b/src/CGContext.cpp
@@ -207,7 +207,7 @@ CGContext::check_read_var(const Variable *v, const std::vector<const Fact*>& fac
 	if (is_nonreadable(v)) {
 		return false;
 	} 
-	if (effect_context.is_written(v) || effect_context.field_is_written(v)) {
+	if (effect_context.is_written_partially(v)) {
 		return false;
 	}
 	if (v->is_volatile() && !effect_context.is_side_effect_free()) {
@@ -329,10 +329,10 @@ CGContext::check_write_var(const Variable *v, const std::vector<const Fact*>& fa
 	if (is_nonwritable(v) || v->is_const()) {
 		return false;
 	}
-	if (effect_context.is_written(v) || effect_context.field_is_written(v)) {
+	if (effect_context.is_written_partially(v)) {
 		return false;
 	}
-	if (effect_context.is_read(v) || effect_context.field_is_read(v)) {
+	if (effect_context.is_read_partially(v)) {
 		return false;
 	}
 	if (v->is_volatile() && !effect_context.is_side_effect_free()) {
@@ -556,7 +556,7 @@ CGContext::in_conflict(const Effect& eff) const
 		if (is_nonreadable(v)) {
 			return true;
 		}
-		if (effect_context.is_written(v) || effect_context.field_is_written(v)) {
+		if (effect_context.is_written_partially(v)) {
 			return true;
 		} 
 		// Yang: do we need to consider deref level here?
@@ -570,10 +570,10 @@ CGContext::in_conflict(const Effect& eff) const
 		if (is_nonwritable(v) || v->is_const()) {
 			return true;
 		}
-		if (effect_context.is_written(v) || effect_context.field_is_written(v)) {
+		if (effect_context.is_written_partially(v)) {
 			return true;
 		}
-		if (effect_context.is_read(v) || effect_context.field_is_read(v)) {
+		if (effect_context.is_read_partially(v)) {
 			return true;
 		}
 		if (v->is_volatile() && !effect_context.is_side_effect_free()) {

diff --git a/src/Effect.cpp b/src/Effect.cpp
@@ -434,6 +434,50 @@ Effect::field_is_written(const Variable *v) const
 	return false;
 }
 
+bool
+Effect::sibling_field_is_read(const Variable *v) const
+{   
+	// check other fields of union/struct
+	if (v->isFieldVarOf_) {
+		for (size_t j=0; j<v->isFieldVarOf_->field_vars.size(); j++) {
+			Variable* field_var = v->isFieldVarOf_->field_vars[j];
+			if (field_var == v) continue;
+			if (is_read(field_var) || field_is_read(field_var)) {
+				return true; 
+			}
+		}
+	}
+	return false;
+}
+
+bool
+Effect::sibling_field_is_written(const Variable *v) const
+{   
+	// check other fields of union/struct
+	if (v->isFieldVarOf_) {
+		for (size_t j=0; j<v->isFieldVarOf_->field_vars.size(); j++) {
+			Variable* field_var = v->isFieldVarOf_->field_vars[j];
+			if (field_var == v) continue;
+			if (is_written(field_var) || field_is_written(field_var)) {
+				return true; 
+			}
+		}
+	}
+	return false;
+}
+
+bool 
+Effect::is_read_partially(const Variable* v) const
+{
+	return is_read(v) || field_is_read(v) || (v->is_union_field() && sibling_field_is_read(v));
+}
+
+bool 
+Effect::is_written_partially(const Variable* v) const
+{
+	return is_written(v) || field_is_written(v) || (v->is_union_field() && sibling_field_is_written(v));
+}
+
 /*
  * consolidate the read/write set 
  */

diff --git a/src/Effect.h b/src/Effect.h
@@ -65,6 +65,10 @@ class Effect
 	bool is_written(std::string vname) const;
 	bool field_is_read(const Variable *v) const;
 	bool field_is_written(const Variable *v) const;
+	bool sibling_field_is_read(const Variable *v) const;
+	bool sibling_field_is_written(const Variable *v) const;
+	bool is_read_partially(const Variable* v) const;  
+	bool is_written_partially(const Variable* v) const;
 	bool has_race_with(const Effect &e) const;
 	bool is_empty(void) const;
 	void consolidate(void);

diff --git a/src/Probabilities.cpp b/src/Probabilities.cpp
@@ -654,10 +654,6 @@ Probabilities::set_default_simple_types_prob()
 	else {
 		SET_SINGLE_NAME("long_long_prob", LongLong, 0);
 		SET_SINGLE_NAME("ulong_long_prob", ULongLong, 0);
-		if (CGOptions::x86_64()) {
-			SET_SINGLE_NAME("long_prob", Long, 0);
-			SET_SINGLE_NAME("ulong_prob", ULong, 0);
-		}
 	}
 
 	set_group_prob(true, pSimpleTypesProb, m);

diff --git a/src/Variable.h b/src/Variable.h
@@ -87,6 +87,7 @@ class Variable
 	bool is_volatile_after_deref(int deref_level) const;
 	bool has_field_var(const Variable* v) const; 
 	bool is_field_var(void) const { return isFieldVarOf_ != 0; };
+	bool is_union_field(void) const { return isFieldVarOf_ != 0 && isFieldVarOf_->type->eType == eUnion; };
 	bool is_array_field(void) const;
 	bool is_virtual(void) const;
 	bool is_aggregate(void) const { return type && type->is_aggregate(); }

diff --git a/src/VariableSelector.cpp b/src/VariableSelector.cpp
@@ -225,10 +225,6 @@ VariableSelector::has_dereferenceable_var(const vector<Variable *>& vars, const
 bool
 VariableSelector::is_eligible_var(const Variable* var, int deref_level, Effect::Access access, const CGContext& cg_context)
 {
-	// JYTODO: integrate this into get_collective?
-	//if (var->isFieldVarOf_ && var->is_array_field()) {
-	//	var = var->isFieldVarOf_->get_collective();
-	//}
 	const Variable* coll = var->get_collective();
 	if (coll != var) {
 		CGContext cg_tmp(cg_context);
@@ -256,15 +252,15 @@ VariableSelector::is_eligible_var(const Variable* var, int deref_level, Effect::
 	// We can neither read nor write a variable that is being written in
 	// the current effect context.
 	if (((access == Effect::READ) || (access == Effect::WRITE))
-		&& (effect_context.is_written(var) || effect_context.field_is_written(var))) {
+		&& (effect_context.is_written_partially(var))) {
 		return false;
 	}
 	// ISSUE: generating "strictly conforming" programs.
 	//
 	// We cannot write a variable that is being read in the current effect context. 
 	// JYTODO: this is too restrictive, with dereference, var is not the variable 
 	// being written, but the pointed variable. Nevertheless, we excluded var here
-	if ((access == Effect::WRITE && deref_level==0) && (effect_context.is_read(var) || effect_context.field_is_read(var))) {
+	if ((access == Effect::WRITE && deref_level==0) && effect_context.is_read_partially(var)) {
 		return false;
 	}
 	// ISSUE: generating correct C programs.
@@ -532,8 +528,6 @@ VariableSelector::GenerateNewGlobal(Effect::Access access, const CGContext &cg_c
 	tmp_count++;
 	Variable* var = create_and_initialize(access, cg_context, t, &var_qfer, 0, name);
 
-	Bookkeeper::record_vars_with_bitfields(t);
-	incr_counter(Bookkeeper::struct_depth_cnts, t->get_struct_depth());
 	GlobalList.push_back(var);
 	// for DFA 
 	FactMgr* fm = get_fact_mgr(&cg_context);
@@ -562,8 +556,6 @@ VariableSelector::GenerateNewNonArrayGlobal(Effect::Access access, const CGConte
 	ERROR_GUARD(NULL);
 	Variable *var = new_variable(name, t, init, qfer);
 
-	Bookkeeper::record_vars_with_bitfields(t);
-	incr_counter(Bookkeeper::struct_depth_cnts, t->get_struct_depth());
 	GlobalList.push_back(var);
 	// for DFA 
 	FactMgr* fm = get_fact_mgr(&cg_context);
@@ -927,9 +919,6 @@ VariableSelector::GenerateNewParentLocal(Block &block,
 	string name = RandomLocalName();
 
 	Variable* var = create_and_initialize(access, cg_context, t, &var_qfer, blk, name);
-
-	Bookkeeper::record_vars_with_bitfields(t);
-	incr_counter(Bookkeeper::struct_depth_cnts, t->get_struct_depth());
 	blk->local_vars.push_back(var);
 	FactMgr* fm = get_fact_mgr(&cg_context);
 	fm->add_new_local_var_fact(blk, var->get_collective());
@@ -1206,10 +1195,17 @@ VariableSelector::select(Effect::Access access,
 	if (var && !cg_context.get_effect_context().is_side_effect_free()) {
 		assert(!var->is_volatile());
 	}
-	if (var_created) {
-		Bookkeeper::use_new_var_cnt++;
-	} else {
-		Bookkeeper::use_old_var_cnt++;
+	// record statistics
+	if (var) {
+		if (var_created) {
+			const Type* t = var->type;
+			Bookkeeper::use_new_var_cnt++; 
+			Bookkeeper::record_vars_with_bitfields(t);
+			incr_counter(Bookkeeper::struct_depth_cnts, t->get_struct_depth());
+			if (t->eType == eUnion) Bookkeeper::union_var_cnt++;
+		} else {
+			Bookkeeper::use_old_var_cnt++;
+		}
 	}
 	return var;
 }
@@ -1355,8 +1351,7 @@ VariableSelector::select_array(const CGContext &cg_context)
 			ArrayVariable* av = dynamic_cast<ArrayVariable*>(vars[i]);
 			assert(av);
 			if (av->collective == 0) {
-				if (!cg_context.get_effect_context().is_read(av) && 
-					!cg_context.get_effect_context().field_is_read(av) &&
+				if (!cg_context.get_effect_context().is_read_partially(av) && 
 					!cg_context.get_effect_context().is_written(av) &&
 					(cg_context.get_effect_context().is_side_effect_free() || !av->is_volatile()) &&
 					!av->is_const() &&