bool StripExternals::runOnModule(Module &M) {
bool Changed = false;
for (Module::iterator I = M.begin(); I != M.end(); ) {
if (I->hasAvailableExternallyLinkage()) {
assert(!I->isDeclaration()&&"Declarations can't be available_externally");
Changed = true;
++NumFunctions;
if (I->use_empty()) {
DEBUG(errs() << "Deleting function: " << *I);
Module::iterator todelete = I;
++I;
todelete->eraseFromParent();
continue;
} else {
I->deleteBody();
DEBUG(errs() << "Deleted function body: " << *I);
}
}
++I;
}
for (Module::global_iterator I = M.global_begin();
I != M.global_end(); ) {
if (I->hasAvailableExternallyLinkage()) {
assert(!I->isDeclaration()&&"Declarations can't be available_externally");
Changed = true;
++NumVariables;
if (I->use_empty()) {
DEBUG(errs() << "Deleting global: " << *I);
Module::global_iterator todelete = I;
++I;
todelete->eraseFromParent();
continue;
} else {
I->setInitializer(0);
I->setLinkage(GlobalValue::ExternalLinkage);
DEBUG(errs() << "Deleted initializer: " << *I);
}
}
++I;
}
return Changed;
}
bool GlobalDCE::runOnModule(Module &M) {
bool Changed = false;
// Loop over the module, adding globals which are obviously necessary.
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
Changed |= RemoveUnusedGlobalValue(*I);
// Functions with external linkage are needed if they have a body
if (!I->isDiscardableIfUnused() &&
!I->isDeclaration() && !I->hasAvailableExternallyLinkage())
GlobalIsNeeded(I);
}
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I) {
Changed |= RemoveUnusedGlobalValue(*I);
// Externally visible & appending globals are needed, if they have an
// initializer.
if (!I->isDiscardableIfUnused() &&
!I->isDeclaration() && !I->hasAvailableExternallyLinkage())
GlobalIsNeeded(I);
}
for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end();
I != E; ++I) {
Changed |= RemoveUnusedGlobalValue(*I);
// Externally visible aliases are needed.
if (!I->isDiscardableIfUnused())
GlobalIsNeeded(I);
}
// Now that all globals which are needed are in the AliveGlobals set, we loop
// through the program, deleting those which are not alive.
//
// The first pass is to drop initializers of global variables which are dead.
std::vector<GlobalVariable*> DeadGlobalVars; // Keep track of dead globals
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I)
if (!AliveGlobals.count(I)) {
DeadGlobalVars.push_back(I); // Keep track of dead globals
I->setInitializer(0);
}
// The second pass drops the bodies of functions which are dead...
std::vector<Function*> DeadFunctions;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!AliveGlobals.count(I)) {
DeadFunctions.push_back(I); // Keep track of dead globals
if (!I->isDeclaration())
I->deleteBody();
}
// The third pass drops targets of aliases which are dead...
std::vector<GlobalAlias*> DeadAliases;
for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end(); I != E;
++I)
if (!AliveGlobals.count(I)) {
DeadAliases.push_back(I);
I->setAliasee(0);
}
if (!DeadFunctions.empty()) {
// Now that all interferences have been dropped, delete the actual objects
// themselves.
for (unsigned i = 0, e = DeadFunctions.size(); i != e; ++i) {
RemoveUnusedGlobalValue(*DeadFunctions[i]);
M.getFunctionList().erase(DeadFunctions[i]);
}
NumFunctions += DeadFunctions.size();
Changed = true;
}
if (!DeadGlobalVars.empty()) {
for (unsigned i = 0, e = DeadGlobalVars.size(); i != e; ++i) {
RemoveUnusedGlobalValue(*DeadGlobalVars[i]);
M.getGlobalList().erase(DeadGlobalVars[i]);
}
NumVariables += DeadGlobalVars.size();
Changed = true;
}
// Now delete any dead aliases.
if (!DeadAliases.empty()) {
for (unsigned i = 0, e = DeadAliases.size(); i != e; ++i) {
RemoveUnusedGlobalValue(*DeadAliases[i]);
M.getAliasList().erase(DeadAliases[i]);
}
NumAliases += DeadAliases.size();
Changed = true;
}
// Make sure that all memory is released
AliveGlobals.clear();
return Changed;
}
bool DelinkPass::runOnModule(Module& M) {
if(DelinkExcept.size()) {
std::ifstream RFI(DelinkExcept.c_str());
DenseSet<GlobalValue*> Keep;
while(!RFI.eof()) {
std::string line;
std::getline(RFI, line);
trim(line);
if(line.empty())
continue;
GlobalValue* GV = M.getNamedValue(line);
if(!GV) {
errs() << "Warning: Skipped " << line << "\n";
continue;
}
Keep.insert(GV);
}
for(Module::iterator it = M.begin(), itend = M.end(); it != itend; ++it) {
if(!Keep.count(it))
it->deleteBody();
}
}
else {
std::ifstream RFI(DelinkSymbols.c_str());
while(!RFI.eof()) {
std::string line;
std::getline(RFI, line);
trim(line);
if(line.empty())
continue;
if(line == "__uClibc_main" || line == "__uClibc_main_spec")
continue;
GlobalValue* GV = M.getNamedValue(line);
if(!GV) {
errs() << "Warning: Skipped " << line << "\n";
continue;
}
if(Function* F = dyn_cast<Function>(GV))
F->deleteBody();
}
}
return true;
}