#include "llvm/CallingConv.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/ADT/SmallPtrSet.h"
+
using namespace llvm;
/// callIsSmall - If a call is likely to lower to a single target instruction,
return Bonus;
}
+// ConstantFunctionBonus - Figure out how much of a bonus we can get for
+// possibly devirtualizing a function. We'll subtract the size of the function
+// we may wish to inline from the indirect call bonus providing a limit on
+// growth. Leave an upper limit of 0 for the bonus - we don't want to penalize
+// inlining because we decide we don't want to give a bonus for
+// devirtualizing.
+int InlineCostAnalyzer::ConstantFunctionBonus(CallSite CS, Constant *C) {
+
+ // This could just be NULL.
+ if (!C) return 0;
+
+ Function *F = dyn_cast<Function>(C);
+ if (!F) return 0;
+
+ int Bonus = InlineConstants::IndirectCallBonus + getInlineSize(CS, F);
+ return (Bonus > 0) ? 0 : Bonus;
+}
+
// CountBonusForConstant - Figure out an approximation for how much per-call
// performance boost we can expect if the specified value is constant.
-unsigned InlineCostAnalyzer::CountBonusForConstant(Value *V) {
+int InlineCostAnalyzer::CountBonusForConstant(Value *V, Constant *C) {
unsigned Bonus = 0;
- bool indirectCallBonus = false;
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
User *U = *UI;
if (CallInst *CI = dyn_cast<CallInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (CI->getCalledValue() == V)
- indirectCallBonus = true;
- }
- else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
+ Bonus += ConstantFunctionBonus(CallSite(CI), C);
+ } else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (II->getCalledValue() == V)
- indirectCallBonus = true;
+ Bonus += ConstantFunctionBonus(CallSite(CI), C);
}
// FIXME: Eliminating conditional branches and switches should
// also yield a per-call performance boost.
}
}
- // FIXME: The only reason we're applying the bonus once is while it's great
- // to devirtualize calls the magnitude of the bonus x number of call sites
- // can lead to a huge code explosion when we prefer to inline 1000 instruction
- // functions that have 10 call sites. This should be made a function of the
- // estimated inline penalty/benefit + the indirect call bonus.
- if (indirectCallBonus) Bonus += InlineConstants::IndirectCallBonus;
+ return Bonus;
+}
+
+int InlineCostAnalyzer::getInlineSize(CallSite CS, Function *Callee) {
+ // 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);
+
+ // 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;
+
+ // Compute any size reductions we can expect due to arguments being 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;
+ }
+
+ // 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);
+
+ // 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.
+
+ // 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 InlineCost;
+}
+
+int InlineCostAnalyzer::getInlineBonuses(CallSite CS, Function *Callee) {
+ // 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);
+
+ bool isDirectCall = CS.getCalledFunction() == Callee;
+ Instruction *TheCall = CS.getInstruction();
+ int Bonus = 0;
+
+ // 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)
+ Bonus += InlineConstants::LastCallToStaticBonus;
+
+ // 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()))
+ Bonus += InlineConstants::NoreturnPenalty;
+ } else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall)))
+ Bonus += InlineConstants::NoreturnPenalty;
+
+ // If this function uses the coldcc calling convention, prefer not to inline
+ // it.
+ if (Callee->getCallingConv() == CallingConv::Cold)
+ Bonus += InlineConstants::ColdccPenalty;
+ // 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.
+ //
+ CallSite::arg_iterator I = CS.arg_begin();
+ for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end();
+ FI != FE; ++I, ++FI)
+ // Compute any constant bonus due to inlining we want to give here.
+ if (isa<Constant>(I))
+ Bonus += CountBonusForConstant(FI, cast<Constant>(I));
+
return Bonus;
}
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
// 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.
+ // be inlined. This value may go negative due to the fact that bonuses
+ // are negative numbers.
//
- 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;
-
+ int InlineCost = getInlineSize(CS, Callee) + getInlineBonuses(CS, Callee);
return llvm::InlineCost::get(InlineCost);
}
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