/// shouldInline - Return true if the inliner should attempt to inline
/// at the given CallSite.
bool Inliner::shouldInline(CallSite CS) {
InlineCost IC = getInlineCost(CS);
float FudgeFactor = getInlineFudgeFactor(CS);
if (IC.isAlways()) {
DOUT << " Inlining: cost=always"
<< ", Call: " << *CS.getInstruction();
return true;
}
if (IC.isNever()) {
DOUT << " NOT Inlining: cost=never"
<< ", Call: " << *CS.getInstruction();
return false;
}
int Cost = IC.getValue();
int CurrentThreshold = InlineThreshold;
Function *Fn = CS.getCaller();
if (Fn && !Fn->isDeclaration()
&& Fn->hasFnAttr(Attribute::OptimizeForSize)
&& InlineThreshold != 50) {
CurrentThreshold = 50;
}
if (Cost >= (int)(CurrentThreshold * FudgeFactor)) {
DOUT << " NOT Inlining: cost=" << Cost
<< ", Call: " << *CS.getInstruction();
return false;
} else {
DOUT << " Inlining: cost=" << Cost
<< ", Call: " << *CS.getInstruction();
return true;
}
}
/// inlineFuctions - Walk all call sites in all functions supplied by
/// client. Inline as many call sites as possible. Delete completely
/// inlined functions.
void BasicInlinerImpl::inlineFunctions() {
// Scan through and identify all call sites ahead of time so that we only
// inline call sites in the original functions, not call sites that result
// from inlining other functions.
std::vector<CallSite> CallSites;
for (std::vector<Function *>::iterator FI = Functions.begin(),
FE = Functions.end(); FI != FE; ++FI) {
Function *F = *FI;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
CallSite CS(cast<Value>(I));
if (CS && CS.getCalledFunction()
&& !CS.getCalledFunction()->isDeclaration())
CallSites.push_back(CS);
}
}
DEBUG(dbgs() << ": " << CallSites.size() << " call sites.\n");
// Inline call sites.
bool Changed = false;
do {
Changed = false;
for (unsigned index = 0; index != CallSites.size() && !CallSites.empty();
++index) {
CallSite CS = CallSites[index];
if (Function *Callee = CS.getCalledFunction()) {
// Eliminate calls that are never inlinable.
if (Callee->isDeclaration() ||
CS.getInstruction()->getParent()->getParent() == Callee) {
CallSites.erase(CallSites.begin() + index);
--index;
continue;
}
InlineCost IC = CA.getInlineCost(CS, NeverInline);
if (IC.isAlways()) {
DEBUG(dbgs() << " Inlining: cost=always"
<<", call: " << *CS.getInstruction());
} else if (IC.isNever()) {
DEBUG(dbgs() << " NOT Inlining: cost=never"
<<", call: " << *CS.getInstruction());
continue;
} else {
int Cost = IC.getValue();
if (Cost >= (int) BasicInlineThreshold) {
DEBUG(dbgs() << " NOT Inlining: cost = " << Cost
<< ", call: " << *CS.getInstruction());
continue;
} else {
DEBUG(dbgs() << " Inlining: cost = " << Cost
<< ", call: " << *CS.getInstruction());
}
}
// Inline
InlineFunctionInfo IFI(0, TD);
if (InlineFunction(CS, IFI)) {
Callee->removeDeadConstantUsers();
if (Callee->isDefTriviallyDead())
DeadFunctions.insert(Callee);
Changed = true;
CallSites.erase(CallSites.begin() + index);
--index;
}
}
}
} while (Changed);
// Remove completely inlined functions from module.
for(SmallPtrSet<Function *, 8>::iterator I = DeadFunctions.begin(),
E = DeadFunctions.end(); I != E; ++I) {
Function *D = *I;
Module *M = D->getParent();
M->getFunctionList().remove(D);
}
}
/// shouldInline - Return true if the inliner should attempt to inline
/// at the given CallSite.
bool Inliner::shouldInline(CallSite CS) {
InlineCost IC = getInlineCost(CS);
if (IC.isAlways()) {
DEBUG(dbgs() << " Inlining: cost=always"
<< ", Call: " << *CS.getInstruction() << "\n");
return true;
}
if (IC.isNever()) {
DEBUG(dbgs() << " NOT Inlining: cost=never"
<< ", Call: " << *CS.getInstruction() << "\n");
return false;
}
int Cost = IC.getValue();
Function *Caller = CS.getCaller();
int CurrentThreshold = getInlineThreshold(CS);
float FudgeFactor = getInlineFudgeFactor(CS);
int AdjThreshold = (int)(CurrentThreshold * FudgeFactor);
if (Cost >= AdjThreshold) {
DEBUG(dbgs() << " NOT Inlining: cost=" << Cost
<< ", thres=" << AdjThreshold
<< ", Call: " << *CS.getInstruction() << "\n");
return false;
}
// Try to detect the case where the current inlining candidate caller
// (call it B) is a static function and is an inlining candidate elsewhere,
// and the current candidate callee (call it C) is large enough that
// inlining it into B would make B too big to inline later. In these
// circumstances it may be best not to inline C into B, but to inline B
// into its callers.
if (Caller->hasLocalLinkage()) {
int TotalSecondaryCost = 0;
bool outerCallsFound = false;
bool allOuterCallsWillBeInlined = true;
bool someOuterCallWouldNotBeInlined = false;
for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
I != E; ++I) {
CallSite CS2(*I);
// If this isn't a call to Caller (it could be some other sort
// of reference) skip it.
if (!CS2 || CS2.getCalledFunction() != Caller)
continue;
InlineCost IC2 = getInlineCost(CS2);
if (IC2.isNever())
allOuterCallsWillBeInlined = false;
if (IC2.isAlways() || IC2.isNever())
continue;
outerCallsFound = true;
int Cost2 = IC2.getValue();
int CurrentThreshold2 = getInlineThreshold(CS2);
float FudgeFactor2 = getInlineFudgeFactor(CS2);
if (Cost2 >= (int)(CurrentThreshold2 * FudgeFactor2))
allOuterCallsWillBeInlined = false;
// See if we have this case. We subtract off the penalty
// for the call instruction, which we would be deleting.
if (Cost2 < (int)(CurrentThreshold2 * FudgeFactor2) &&
Cost2 + Cost - (InlineConstants::CallPenalty + 1) >=
(int)(CurrentThreshold2 * FudgeFactor2)) {
someOuterCallWouldNotBeInlined = true;
TotalSecondaryCost += Cost2;
}
}
// If all outer calls to Caller would get inlined, the cost for the last
// one is set very low by getInlineCost, in anticipation that Caller will
// be removed entirely. We did not account for this above unless there
// is only one caller of Caller.
if (allOuterCallsWillBeInlined && Caller->use_begin() != Caller->use_end())
TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
if (outerCallsFound && someOuterCallWouldNotBeInlined &&
TotalSecondaryCost < Cost) {
DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() <<
" Cost = " << Cost <<
", outer Cost = " << TotalSecondaryCost << '\n');
return false;
}
}
DEBUG(dbgs() << " Inlining: cost=" << Cost
<< ", thres=" << AdjThreshold
<< ", Call: " << *CS.getInstruction() << '\n');
return true;
}
/// shouldInline - Return true if the inliner should attempt to inline
/// at the given CallSite.
bool Inliner::shouldInline(CallSite CS) {
InlineCost IC = getInlineCost(CS);
if (IC.isAlways()) {
DEBUG(dbgs() << " Inlining: cost=always"
<< ", Call: " << *CS.getInstruction() << "\n");
return true;
}
if (IC.isNever()) {
DEBUG(dbgs() << " NOT Inlining: cost=never"
<< ", Call: " << *CS.getInstruction() << "\n");
return false;
}
int Cost = IC.getValue();
Function *Caller = CS.getCaller();
int CurrentThreshold = getInlineThreshold(CS);
float FudgeFactor = getInlineFudgeFactor(CS);
int AdjThreshold = (int)(CurrentThreshold * FudgeFactor);
if (Cost >= AdjThreshold) {
DEBUG(dbgs() << " NOT Inlining: cost=" << Cost
<< ", thres=" << AdjThreshold
<< ", Call: " << *CS.getInstruction() << "\n");
return false;
}
// Try to detect the case where the current inlining candidate caller (call
// it B) is a static or linkonce-ODR function and is an inlining candidate
// elsewhere, and the current candidate callee (call it C) is large enough
// that inlining it into B would make B too big to inline later. In these
// circumstances it may be best not to inline C into B, but to inline B into
// its callers.
//
// This only applies to static and linkonce-ODR functions because those are
// expected to be available for inlining in the translation units where they
// are used. Thus we will always have the opportunity to make local inlining
// decisions. Importantly the linkonce-ODR linkage covers inline functions
// and templates in C++.
if (Caller->hasLocalLinkage() ||
Caller->getLinkage() == GlobalValue::LinkOnceODRLinkage) {
int TotalSecondaryCost = 0;
bool outerCallsFound = false;
// This bool tracks what happens if we do NOT inline C into B.
bool callerWillBeRemoved = true;
// This bool tracks what happens if we DO inline C into B.
bool inliningPreventsSomeOuterInline = false;
for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
I != E; ++I) {
CallSite CS2(*I);
// If this isn't a call to Caller (it could be some other sort
// of reference) skip it. Such references will prevent the caller
// from being removed.
if (!CS2 || CS2.getCalledFunction() != Caller) {
callerWillBeRemoved = false;
continue;
}
InlineCost IC2 = getInlineCost(CS2);
if (IC2.isNever())
callerWillBeRemoved = false;
if (IC2.isAlways() || IC2.isNever())
continue;
outerCallsFound = true;
int Cost2 = IC2.getValue();
int CurrentThreshold2 = getInlineThreshold(CS2);
float FudgeFactor2 = getInlineFudgeFactor(CS2);
if (Cost2 >= (int)(CurrentThreshold2 * FudgeFactor2))
callerWillBeRemoved = false;
// See if we have this case. We subtract off the penalty
// for the call instruction, which we would be deleting.
if (Cost2 < (int)(CurrentThreshold2 * FudgeFactor2) &&
Cost2 + Cost - (InlineConstants::CallPenalty + 1) >=
(int)(CurrentThreshold2 * FudgeFactor2)) {
inliningPreventsSomeOuterInline = true;
TotalSecondaryCost += Cost2;
}
}
// If all outer calls to Caller would get inlined, the cost for the last
// one is set very low by getInlineCost, in anticipation that Caller will
// be removed entirely. We did not account for this above unless there
// is only one caller of Caller.
if (callerWillBeRemoved && Caller->use_begin() != Caller->use_end())
TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
if (outerCallsFound && inliningPreventsSomeOuterInline &&
TotalSecondaryCost < Cost) {
DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() <<
" Cost = " << Cost <<
", outer Cost = " << TotalSecondaryCost << '\n');
return false;
}
}
DEBUG(dbgs() << " Inlining: cost=" << Cost
<< ", thres=" << AdjThreshold
<< ", Call: " << *CS.getInstruction() << '\n');
return true;
}