InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, Function *Callee) {
Instruction *TheCall = CS.getInstruction();
Function *Caller = TheCall->getParent()->getParent();
// Don't inline functions which can be redefined at link-time to mean
// something else. Don't inline functions marked noinline or call sites
// marked noinline.
if (Callee->mayBeOverridden() || Callee->hasFnAttr(Attribute::NoInline) ||
CS.isNoInline())
return llvm::InlineCost::getNever();
// Get information about the callee.
FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
// If we haven't calculated this information yet, do so now.
if (CalleeFI->Metrics.NumBlocks == 0)
CalleeFI->analyzeFunction(Callee, TD);
// If we should never inline this, return a huge cost.
if (CalleeFI->NeverInline())
return InlineCost::getNever();
// FIXME: It would be nice to kill off CalleeFI->NeverInline. Then we
// could move this up and avoid computing the FunctionInfo for
// things we are going to just return always inline for. This
// requires handling setjmp somewhere else, however.
if (!Callee->isDeclaration() && Callee->hasFnAttr(Attribute::AlwaysInline))
return InlineCost::getAlways();
if (CalleeFI->Metrics.usesDynamicAlloca) {
// Get information about the caller.
FunctionInfo &CallerFI = CachedFunctionInfo[Caller];
// If we haven't calculated this information yet, do so now.
if (CallerFI.Metrics.NumBlocks == 0) {
CallerFI.analyzeFunction(Caller, TD);
// Recompute the CalleeFI pointer, getting Caller could have invalidated
// it.
CalleeFI = &CachedFunctionInfo[Callee];
}
// Don't inline a callee with dynamic alloca into a caller without them.
// Functions containing dynamic alloca's are inefficient in various ways;
// don't create more inefficiency.
if (!CallerFI.Metrics.usesDynamicAlloca)
return InlineCost::getNever();
}
// InlineCost - This value measures how good of an inline candidate this call
// site is to inline. A lower inline cost make is more likely for the call to
// be inlined. This value may go negative due to the fact that bonuses
// are negative numbers.
//
int InlineCost = getInlineSize(CS, Callee) + getInlineBonuses(CS, Callee);
return llvm::InlineCost::get(InlineCost);
}
InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
Function *Callee,
SmallPtrSet<const Function*, 16> &NeverInline) {
Instruction *TheCall = CS.getInstruction();
Function *Caller = TheCall->getParent()->getParent();
bool isDirectCall = CS.getCalledFunction() == Callee;
// Don't inline functions which can be redefined at link-time to mean
// something else. Don't inline functions marked noinline or call sites
// marked noinline.
if (Callee->mayBeOverridden() ||
Callee->hasFnAttr(Attribute::NoInline) || NeverInline.count(Callee) ||
CS.isNoInline())
return llvm::InlineCost::getNever();
// Get information about the callee.
FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
// If we haven't calculated this information yet, do so now.
if (CalleeFI->Metrics.NumBlocks == 0)
CalleeFI->analyzeFunction(Callee);
// If we should never inline this, return a huge cost.
if (CalleeFI->NeverInline())
return InlineCost::getNever();
// FIXME: It would be nice to kill off CalleeFI->NeverInline. Then we
// could move this up and avoid computing the FunctionInfo for
// things we are going to just return always inline for. This
// requires handling setjmp somewhere else, however.
if (!Callee->isDeclaration() && Callee->hasFnAttr(Attribute::AlwaysInline))
return InlineCost::getAlways();
if (CalleeFI->Metrics.usesDynamicAlloca) {
// Get infomation about the caller.
FunctionInfo &CallerFI = CachedFunctionInfo[Caller];
// If we haven't calculated this information yet, do so now.
if (CallerFI.Metrics.NumBlocks == 0) {
CallerFI.analyzeFunction(Caller);
// Recompute the CalleeFI pointer, getting Caller could have invalidated
// it.
CalleeFI = &CachedFunctionInfo[Callee];
}
// Don't inline a callee with dynamic alloca into a caller without them.
// Functions containing dynamic alloca's are inefficient in various ways;
// don't create more inefficiency.
if (!CallerFI.Metrics.usesDynamicAlloca)
return InlineCost::getNever();
}
// InlineCost - This value measures how good of an inline candidate this call
// site is to inline. A lower inline cost make is more likely for the call to
// be inlined. This value may go negative.
//
int InlineCost = 0;
// Add to the inline quality for properties that make the call valuable to
// inline. This includes factors that indicate that the result of inlining
// the function will be optimizable. Currently this just looks at arguments
// passed into the function.
//
unsigned ArgNo = 0;
CallSite::arg_iterator I = CS.arg_begin();
for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end();
FI != FE; ++I, ++FI, ++ArgNo) {
// If an alloca is passed in, inlining this function is likely to allow
// significant future optimization possibilities (like scalar promotion, and
// scalarization), so encourage the inlining of the function.
//
if (isa<AllocaInst>(I))
InlineCost -= CalleeFI->ArgumentWeights[ArgNo].AllocaWeight;
// If this is a constant being passed into the function, use the argument
// weights calculated for the callee to determine how much will be folded
// away with this information.
else if (isa<Constant>(I)) {
InlineCost -= CalleeFI->ArgumentWeights[ArgNo].ConstantWeight;
// Compute any constant bonus due to inlining we want to give here.
InlineCost -= CountBonusForConstant(FI);
}
}
// Each argument passed in has a cost at both the caller and the callee
// sides. Measurements show that each argument costs about the same as an
// instruction.
InlineCost -= (CS.arg_size() * InlineConstants::InstrCost);
// If there is only one call of the function, and it has internal linkage,
// make it almost guaranteed to be inlined.
//
if (Callee->hasLocalLinkage() && Callee->hasOneUse() && isDirectCall)
InlineCost += InlineConstants::LastCallToStaticBonus;
// Now that we have considered all of the factors that make the call site more
// likely to be inlined, look at factors that make us not want to inline it.
// If the instruction after the call, or if the normal destination of the
// invoke is an unreachable instruction, the function is noreturn. As such,
// there is little point in inlining this.
if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
if (isa<UnreachableInst>(II->getNormalDest()->begin()))
InlineCost += InlineConstants::NoreturnPenalty;
} else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall)))
InlineCost += InlineConstants::NoreturnPenalty;
// If this function uses the coldcc calling convention, prefer not to inline
// it.
if (Callee->getCallingConv() == CallingConv::Cold)
InlineCost += InlineConstants::ColdccPenalty;
// Calls usually take a long time, so they make the inlining gain smaller.
InlineCost += CalleeFI->Metrics.NumCalls * InlineConstants::CallPenalty;
// Look at the size of the callee. Each instruction counts as 5.
InlineCost += CalleeFI->Metrics.NumInsts*InlineConstants::InstrCost;
return llvm::InlineCost::get(InlineCost);
}
