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Merge pull request 'dead_code_removing' (#25) from dead_code_removing into master

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This commit was merged in pull request #25.
This commit is contained in:
Alexander_KS
2024-02-02 17:32:49 +00:00
parent 00c539eff4 42fe628ce0
commit 6b02c756c8
5 changed files with 192 additions and 84 deletions
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16
sapfor/experts/Sapfor_2017/_src/CFGraph/CFGraph.cpp
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@@ -56,6 +56,22 @@ void BBlock::addInstruction(IR_Block* item)
item->setBasicBlock(this);
}
int BBlock::removePrev(BBlock* removed)
{
auto it = std::remove(prev.begin(), prev.end(), removed);
auto r = prev.end() - it;
prev.erase(it, prev.end());
return r;
}
int BBlock::removeNext(BBlock* removed)
{
auto it = std::remove(next.begin(), next.end(), removed);
auto r = next.end() - it;
next.erase(it, next.end());
return r;
}
BBlock::~BasicBlock()
{
for (auto& instr : instructions)

3
sapfor/experts/Sapfor_2017/_src/CFGraph/CFGraph.h
View File

@@ -43,6 +43,9 @@ namespace SAPFOR
void addPrev(BasicBlock* prev_) { prev.push_back(prev_); }
void addNext(BasicBlock* next_) { next.push_back(next_); }
int removePrev(BasicBlock* removed);
int removeNext(BasicBlock* removed);
void replacePrevNext(const std::map<BasicBlock*, BasicBlock*>& oldToNew)
{
for (int z = 0; z < next.size(); ++z)

125
sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp
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@@ -321,38 +321,6 @@ static bool getDependencies(SAPFOR::Argument* var, SAPFOR::Instruction* instr, c
return true;
}
static bool ifVariableValid(SAPFOR::Argument* var, const set<pair<SAPFOR::Instruction*, SAPFOR::BasicBlock*>>& defs,
SAPFOR::Argument* processed_var, const pair<SAPFOR::Instruction*, SAPFOR::BasicBlock*>& def_of_processed_var)
{
const auto& BB_of_def_of_processed_var = def_of_processed_var.second;
if (defs.size() == 1)
{
const auto& def = *defs.begin();
if (def.second == BB_of_def_of_processed_var && def.first->getNumber() < def_of_processed_var.first->getNumber())
return true;
}
const auto& RD_In_BB_of_def_of_processed_var = BB_of_def_of_processed_var->getRD_In();
auto RD_of_var_from_BB_with_processed_var = RD_In_BB_of_def_of_processed_var.find(var);
if (RD_of_var_from_BB_with_processed_var != RD_In_BB_of_def_of_processed_var.end()
&& RD_of_var_from_BB_with_processed_var->second.size() == defs.size())
{
for (const auto& def : defs)
{
int number_of_istruction_with_decl = def.first ? def.first->getNumber() : CFG_VAL::UNINIT;
if (RD_of_var_from_BB_with_processed_var->second.count(number_of_istruction_with_decl) == 0)
return false;
}
return true;
}
return false;
}
static const set<SAPFOR::Argument*>& func_affects(const FuncInfo* func, const vector<SAPFOR::BasicBlock*>& blocks)
{
static map<const FuncInfo*, set<SAPFOR::Argument*>> affects;
@@ -1150,7 +1118,7 @@ vector<SAPFOR::BasicBlock*> sortCfgNodes(const vector<SAPFOR::BasicBlock*>& bloc
if (!nodes_added && processing_stack.size() != 0) {
//there is some blocks in the stack but no one can be processed
//this code should be unreachable
#ifdef DEBUG_CHECKS
#if DEBUG_CHECKS
printInternalError(convertFileName(__FILE__).c_str(), __LINE__);
#endif // DEBUG_CHECKS
auto block = processing_stack.back();
@@ -1167,7 +1135,7 @@ vector<SAPFOR::BasicBlock*> sortCfgNodes(const vector<SAPFOR::BasicBlock*>& bloc
}
}
#ifdef DEBUG_CHECKS
#if DEBUG_CHECKS
set<SAPFOR::BasicBlock*> verify_unique;
verify_unique.insert(result.begin(), result.end());
@@ -1176,7 +1144,7 @@ vector<SAPFOR::BasicBlock*> sortCfgNodes(const vector<SAPFOR::BasicBlock*>& bloc
verify_unique.clear();
#endif // DEBUG_CHECKS
#ifdef DEBUG_CHECKS
#if DEBUG_CHECKS
set<SAPFOR::BasicBlock*> all_blocks, res_blocks;
all_blocks.insert(blocks.begin(), blocks.end());
@@ -1267,7 +1235,7 @@ bool isArgReaches(int decl_instr, SAPFOR::BasicBlock* decl_bb,
if (RDs_for_arg.size() == 1)
{
const int rd = *RDs_for_arg.begin();
if (rd >= decl_bb->getInstructions().front()->getNumber() && rd <= decl_instr)
if (rd >= decl_bb->getInstructions().front()->getNumber() && rd < decl_instr)
return true;
}
@@ -1275,7 +1243,67 @@ bool isArgReaches(int decl_instr, SAPFOR::BasicBlock* decl_bb,
if (arg_in_from_decl_it == decl_bb->getRD_In().end())
return false;
return arg_in_from_decl_it->second == RDs_for_arg;
if(arg_in_from_decl_it->second != RDs_for_arg)
return false;
set<SAPFOR::BasicBlock*> reachable = { decl_bb };
set<int> banned_instructions;
for (int instr_def : arg_in_from_decl_it->second)
if (instr_def >= decl_instr || instr_def < decl_bb->getInstructions().front()->getNumber())
//try to find way [decl_bb] -> [dest_bb] with redefining of var (that means that var value from decl_bb could be overwrited)
banned_instructions.insert(instr_def);
set<SAPFOR::BasicBlock*> worklist = reachable, banned_blocks;
bool way_found = false;
while (worklist.size() != 0 && banned_instructions.size() != 0)
{
for (SAPFOR::BasicBlock* wl : worklist)
{
int start = wl->getInstructions().front()->getNumber(), end = wl->getInstructions().back()->getNumber();
for (auto banned_it = banned_instructions.begin(); banned_it != banned_instructions.end();)
{
if(start <= *banned_it && *banned_it <= end)
{
banned_it = banned_instructions.erase(banned_it);
banned_blocks.insert(wl);
}
else
{
banned_it++;
}
}
}
set<SAPFOR::BasicBlock*> to_insert;
for (auto b : worklist)
for (auto next : b->getNext())
if (reachable.insert(next).second)
to_insert.insert(next);
worklist = to_insert;
}
reachable = banned_blocks;
worklist = reachable;
while (worklist.size() != 0 || banned_instructions.size() == 0)
{
if(worklist.find(dest_bb) != worklist.end())
return false;
set<SAPFOR::BasicBlock*> to_insert;
for (auto b : worklist)
for (auto next : b->getNext())
if(next != decl_bb)
if (reachable.insert(next).second)
to_insert.insert(next);
worklist = to_insert;
}
return true;
}
// return arg's definition if it really reaches dest_bb
@@ -1597,28 +1625,7 @@ void buildSubstitutions(const map<FuncInfo*, vector<SAPFOR::BasicBlock*>>& CFGra
for (SAPFOR::Argument* dep : dependencies_of_var->second)
{
if (dep->getType() != CFG_ARG_TYPE::VAR)
{
can_use = false;
break;
}
const auto& RD_In_of_curr_BB = cur_BB->getRD_In();
auto dep_from_curr_RD_In = RD_In_of_curr_BB.find(dep);
if (dep_from_curr_RD_In == RD_In_of_curr_BB.end())
{
can_use = false;
break;
}
const auto& RDs_for_dep = dep_from_curr_RD_In->second;
set<pair<SAPFOR::Instruction*, SAPFOR::BasicBlock*>> defs_of_dep;
for (int def_instruction_num : RDs_for_dep)
defs_of_dep.insert(getInstructionAndBlockByNumber(CFGraph_for_project, def_instruction_num));
if (!ifVariableValid(dep, defs_of_dep, in_val.first, instr_and_bb))
if (!isArgReaches(instr_num, instr_and_bb.second, dep, cur_BB))
{
can_use = false;
break;

14
sapfor/experts/Sapfor_2017/_src/CFGraph/live_variable_analysis.cpp
View File

@@ -338,7 +338,7 @@ void getUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instruction* ins
if ((instr_operation == SAPFOR::CFG_OP::F_CALL || instr_operation == SAPFOR::CFG_OP::PARAM) && last_param_ref_index < 0) {
auto func_it = funcByName.find(fName);
if (func_it != funcByName.end())
if (interprocedural && func_it != funcByName.end())
{
fcalls.push_back(LiveDeadVarsForCall(func_it->second, block, lastParamRef));
@@ -360,6 +360,18 @@ void getUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instruction* ins
use.insert(make_live.begin(), make_live.end());
def.insert(make_dead.begin(), make_dead.end());
}
else if (func_it != funcByName.end())
{
int arg_num = lastParamRef.size();
for (int i = 0; i < arg_num; i++)
{
if(func_it->second->funcParams.isArgOut(i))
def.insert(lastParamRef[i]);
if (func_it->second->funcParams.isArgIn(i))
use.insert(lastParamRef[i]);
}
}
else
use.insert(lastParamRef.begin(), lastParamRef.end());

116
sapfor/experts/Sapfor_2017/_src/Transformations/dead_code.cpp
View File

@@ -4,35 +4,34 @@
#include <string>
#include <vector>
#include <set>
#include <algorithm>
using std::map;
using std::string;
using std::vector;
using std::set;
using std::remove_if;
#define PRINT_USELESS_STATEMENTS 0
static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instruction* instr,
set<SAPFOR::Argument*>& use, set<SAPFOR::Argument*>& def,
vector<SAPFOR::Argument*>& formal_parameters,
vector<SAPFOR::Argument*>& lastParamRef, int& last_param_ref_index, int& last_param_ref_size,
string& fName,
string& fName, const map<string, FuncInfo*>& funcByName,
bool& useful, bool& last_fcall_useful,
set<SAPFOR::Argument*>& usedByThisBlock)
{
set<SAPFOR::Argument*> res, args;
if (fName == "")
last_fcall_useful = false;
vector<LIVE_VARIABLES::LiveDeadVarsForCall> fcalls;
getUseDefForInstruction(block, instr,
args, res,
formal_parameters, fcalls,
lastParamRef, last_param_ref_index, last_param_ref_size,
fName, {},
fName, funcByName,
false
);
@@ -59,15 +58,18 @@ static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instru
SAPFOR::CFG_OP::ENTRY,
SAPFOR::CFG_OP::EXIT,
SAPFOR::CFG_OP::DVM_DIR,
SAPFOR::CFG_OP::SPF_DIR,
SAPFOR::CFG_OP::F_CALL //TODO: handle pure functions
SAPFOR::CFG_OP::SPF_DIR
};
if (always_useful.find(instr->getOperation()) != always_useful.end())
useful = true;
else if(instr->getOperation() == SAPFOR::CFG_OP::PARAM && last_fcall_useful)
useful = true;
else if (instr->getOperation() == SAPFOR::CFG_OP::F_CALL)
{
auto func_it = funcByName.find(instr->getArg1()->getValue());
useful |= func_it == funcByName.end() || !(func_it->second->isPure);
}
else if (instr->getOperation() == SAPFOR::CFG_OP::PARAM)
useful |= last_fcall_useful;
}
if (useful)
@@ -89,13 +91,16 @@ static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instru
insertIfVar(args.begin(), args.end(), usedByThisBlock);
}
if ((instr->getOperation() == SAPFOR::CFG_OP::F_CALL || instr->getOperation() == SAPFOR::CFG_OP::PARAM) && fName == "")
last_fcall_useful = false;
}
//Build use and def sets of block. Result are stored in use and def
static void buildUseDef(SAPFOR::BasicBlock* block, set<SAPFOR::Argument*>& use, set<SAPFOR::Argument*>& def,
vector<SAPFOR::Argument*>& formal_parameters, vector<bool>& useful,
set<SAPFOR::Argument*>& usedByThisBlock)
set<SAPFOR::Argument*>& usedByThisBlock, const map<string, FuncInfo*>& funcByName)
{
set<SAPFOR::Argument*> use_with_regs = use, def_with_regs = def;
@@ -115,7 +120,7 @@ static void buildUseDef(SAPFOR::BasicBlock* block, set<SAPFOR::Argument*>& use,
use_with_regs, def_with_regs,
formal_parameters,
lastParamRef, last_param_ref_index, last_param_ref_size,
fName,
fName, funcByName,
u, last_fcall_useful,
usedByThisBlock
);
@@ -136,6 +141,7 @@ private:
bool useful_jump = false;
vector<SAPFOR::Argument*>& formal_parameters;
const map<string, FuncInfo*>& funcByName;
public:
bool updateJumpStatus()
{
@@ -223,7 +229,7 @@ public:
use.insert(byArg.first);
set<SAPFOR::Argument*> usedByThisBlock;
buildUseDef(bb, use, def, this->formal_parameters, useful, usedByThisBlock);
buildUseDef(bb, use, def, this->formal_parameters, useful, usedByThisBlock, funcByName);
auto in = bb->getLiveIn(), out = bb->getLiveOut();
@@ -283,15 +289,19 @@ public:
return inserted;
}
DeadCodeAnalysisNode(SAPFOR::BasicBlock* block, vector<SAPFOR::Argument*>& formal_parameters) :
formal_parameters(formal_parameters)
DeadCodeAnalysisNode(SAPFOR::BasicBlock* block,
vector<SAPFOR::Argument*>& formal_parameters,
const map<string, FuncInfo*>& funcByName)
:
formal_parameters(formal_parameters),
funcByName(funcByName)
{
setBlock(block);
useful.resize(block->getInstructions().size(), false);
set<SAPFOR::Argument*> use, def;
set<SAPFOR::Argument*> usedByThisBlock;
buildUseDef(getBlock(), use, def, this->formal_parameters, useful, usedByThisBlock);
buildUseDef(getBlock(), use, def, this->formal_parameters, useful, usedByThisBlock, funcByName);
for (SAPFOR::Argument* arg : use)
getBlock()->addLiveIn({ { arg, { getBlock() } } });
@@ -303,13 +313,16 @@ public:
class DeadCodeAnalysis : public BackwardDataFlowAnalysis<DeadCodeAnalysisNode> {
protected:
vector<SAPFOR::Argument*>& formal_parameters;
const map<string, FuncInfo*>& funcByName;
DeadCodeAnalysisNode* createNode(SAPFOR::BasicBlock* block) override {
return new DeadCodeAnalysisNode(block, formal_parameters);
return new DeadCodeAnalysisNode(block, formal_parameters, funcByName);
}
public:
DeadCodeAnalysis(vector<SAPFOR::Argument*>& formal_parameters) :
formal_parameters(formal_parameters)
DeadCodeAnalysis(vector<SAPFOR::Argument*>& formal_parameters, const map<string, FuncInfo*>& funcByName)
:
formal_parameters(formal_parameters),
funcByName(funcByName)
{ }
};
@@ -325,15 +338,67 @@ void removeDeadCode(SgStatement* func,
if(cfg.size() != 1)
printInternalError(convertFileName(__FILE__).c_str(), __LINE__);
const auto& cfg_pair = *(cfg.begin());
auto& cfg_pair = *(cfg.begin());
// delete unreachable blocks
set<SAPFOR::BasicBlock*> reachable;
for (auto b : cfg_pair.second)
if(b->getInstructions().front()->isHeader())
reachable.insert(b);
set<SAPFOR::BasicBlock*> worklist = reachable;
while (worklist.size() != 0)
{
set<SAPFOR::BasicBlock*> to_insert;
for(auto b : worklist)
for(auto next: b->getNext())
if(reachable.insert(next).second)
to_insert.insert(next);
worklist = to_insert;
}
auto remove_unreachable_it = remove_if(cfg_pair.second.begin(), cfg_pair.second.end(),
[&reachable](SAPFOR::BasicBlock* b)
{
if (reachable.find(b) == reachable.end())
{
for(auto next: b->getNext())
if(reachable.find(next) != reachable.end())
next->removePrev(b);
delete b;
return true;
}
return false;
}
);
reachable.clear();
cfg_pair.second.erase(remove_unreachable_it, cfg_pair.second.end());
// detect useless code
vector<SAPFOR::Argument*> func_parameters(cfg_pair.first->funcParams.countOfPars, NULL);
DeadCodeAnalysis analysis_object(func_parameters);
map<string, FuncInfo*> funcByName;
for (auto& byFile : allFuncs)
for (auto byFunc : byFile.second)
funcByName[byFunc->funcName] = byFunc;
DeadCodeAnalysis analysis_object(func_parameters, funcByName);
analysis_object.fit(cfg_pair.second);
analysis_object.analyze();
// detect dead statements
set<SgStatement*> useful;
for (DeadCodeAnalysisNode* byNode : analysis_object.getNodes())
@@ -358,11 +423,16 @@ void removeDeadCode(SgStatement* func,
}
}
// remove dead statements
SgStatement* end = func->lastNodeOfStmt(), *st = func;
set<int> removable =
{
ASSIGN_STAT
ASSIGN_STAT,
PROC_STAT,
WRITE_STAT,
READ_STAT
};
while (st != end)