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-rw-r--r--lib/Analysis/InlineCost.cpp313
1 files changed, 181 insertions, 132 deletions
diff --git a/lib/Analysis/InlineCost.cpp b/lib/Analysis/InlineCost.cpp
index b103897..47f91cf 100644
--- a/lib/Analysis/InlineCost.cpp
+++ b/lib/Analysis/InlineCost.cpp
@@ -16,6 +16,7 @@
#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,
@@ -142,55 +143,6 @@ void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB) {
NumBBInsts[BB] = NumInsts - NumInstsBeforeThisBB;
}
-// CountBonusForConstant - Figure out an approximation for how much per-call
-// performance boost we can expect if the specified value is constant.
-unsigned CodeMetrics::CountBonusForConstant(Value *V) {
- unsigned Bonus = 0;
- 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)
- Bonus += InlineConstants::IndirectCallBonus;
- }
- else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
- // Turning an indirect call into a direct call is a BIG win
- if (II->getCalledValue() == V)
- Bonus += InlineConstants::IndirectCallBonus;
- }
- // FIXME: Eliminating conditional branches and switches should
- // also yield a per-call performance boost.
- else {
- // Figure out the bonuses that wll accrue due to simple constant
- // propagation.
- Instruction &Inst = cast<Instruction>(*U);
-
- // We can't constant propagate instructions which have effects or
- // read memory.
- //
- // FIXME: It would be nice to capture the fact that a load from a
- // pointer-to-constant-global is actually a *really* good thing to zap.
- // Unfortunately, we don't know the pointer that may get propagated here,
- // so we can't make this decision.
- if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
- isa<AllocaInst>(Inst))
- continue;
-
- bool AllOperandsConstant = true;
- for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
- if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
- AllOperandsConstant = false;
- break;
- }
-
- if (AllOperandsConstant)
- Bonus += CountBonusForConstant(&Inst);
- }
- }
- return Bonus;
-}
-
-
// CountCodeReductionForConstant - Figure out an approximation for how many
// instructions will be constant folded if the specified value is constant.
//
@@ -290,27 +242,19 @@ void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
if (Metrics.NumRets==1)
--Metrics.NumInsts;
- // Don't bother calculating argument weights if we are never going to inline
- // the function anyway.
- if (NeverInline())
- return;
-
// Check out all of the arguments to the function, figuring out how much
// code can be eliminated if one of the arguments is a constant.
ArgumentWeights.reserve(F->arg_size());
for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
ArgumentWeights.push_back(ArgInfo(Metrics.CountCodeReductionForConstant(I),
- Metrics.CountCodeReductionForAlloca(I),
- Metrics.CountBonusForConstant(I)));
+ Metrics.CountCodeReductionForAlloca(I)));
}
/// NeverInline - returns true if the function should never be inlined into
/// any caller
-bool InlineCostAnalyzer::FunctionInfo::NeverInline()
-{
+bool InlineCostAnalyzer::FunctionInfo::NeverInline() {
return (Metrics.callsSetJmp || Metrics.isRecursive ||
Metrics.containsIndirectBr);
-
}
// getSpecializationBonus - The heuristic used to determine the per-call
// performance boost for using a specialization of Callee with argument
@@ -334,12 +278,15 @@ int InlineCostAnalyzer::getSpecializationBonus(Function *Callee,
if (CalleeFI->Metrics.NumBlocks == 0)
CalleeFI->analyzeFunction(Callee);
+ unsigned ArgNo = 0;
+ unsigned i = 0;
+ for (Function::arg_iterator I = Callee->arg_begin(), E = Callee->arg_end();
+ I != E; ++I, ++ArgNo)
+ if (ArgNo == SpecializedArgNos[i]) {
+ ++i;
+ Bonus += CountBonusForConstant(I);
+ }
- for (unsigned i = 0, s = SpecializedArgNos.size();
- i < s; ++i )
- {
- Bonus += CalleeFI->ArgumentWeights[SpecializedArgNos[i]].ConstantBonus;
- }
// Calls usually take a long time, so they make the specialization gain
// smaller.
Bonus -= CalleeFI->Metrics.NumCalls * InlineConstants::CallPenalty;
@@ -347,6 +294,171 @@ int InlineCostAnalyzer::getSpecializationBonus(Function *Callee,
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.
+int InlineCostAnalyzer::CountBonusForConstant(Value *V, Constant *C) {
+ unsigned Bonus = 0;
+ 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)
+ 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)
+ Bonus += ConstantFunctionBonus(CallSite(II), C);
+ }
+ // FIXME: Eliminating conditional branches and switches should
+ // also yield a per-call performance boost.
+ else {
+ // Figure out the bonuses that wll accrue due to simple constant
+ // propagation.
+ Instruction &Inst = cast<Instruction>(*U);
+
+ // We can't constant propagate instructions which have effects or
+ // read memory.
+ //
+ // FIXME: It would be nice to capture the fact that a load from a
+ // pointer-to-constant-global is actually a *really* good thing to zap.
+ // Unfortunately, we don't know the pointer that may get propagated here,
+ // so we can't make this decision.
+ if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
+ isa<AllocaInst>(Inst))
+ continue;
+
+ bool AllOperandsConstant = true;
+ for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
+ if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
+ AllOperandsConstant = false;
+ break;
+ }
+
+ if (AllOperandsConstant)
+ Bonus += CountBonusForConstant(&Inst);
+ }
+ }
+
+ 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;
+}
// getInlineCost - The heuristic used to determine if we should inline the
// function call or not.
@@ -361,7 +473,6 @@ InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
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
@@ -371,32 +482,6 @@ InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
CS.isNoInline())
return llvm::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;
-
- // 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;
-
- // If this function uses the coldcc calling convention, prefer not to inline
- // it.
- if (Callee->getCallingConv() == CallingConv::Cold)
- InlineCost += InlineConstants::ColdccPenalty;
-
- // 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;
-
// Get information about the callee.
FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
@@ -435,46 +520,12 @@ InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
return InlineCost::getNever();
}
- // 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.
+ // 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.
//
- unsigned ArgNo = 0;
- for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
- I != E; ++I, ++ArgNo) {
- // 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 -= InlineConstants::InstrCost;
-
- // 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)) {
- if (ArgNo < CalleeFI->ArgumentWeights.size())
- 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)) {
- if (ArgNo < CalleeFI->ArgumentWeights.size())
- InlineCost -= (CalleeFI->ArgumentWeights[ArgNo].ConstantWeight +
- CalleeFI->ArgumentWeights[ArgNo].ConstantBonus);
- }
- }
-
- // 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;
-
+ int InlineCost = getInlineSize(CS, Callee) + getInlineBonuses(CS, Callee);
return llvm::InlineCost::get(InlineCost);
}
@@ -505,9 +556,7 @@ InlineCost InlineCostAnalyzer::getSpecializationCost(Function *Callee,
// away with the given arguments replaced by constants.
for (SmallVectorImpl<unsigned>::iterator an = SpecializedArgNos.begin(),
ae = SpecializedArgNos.end(); an != ae; ++an)
- {
Cost -= CalleeFI->ArgumentWeights[*an].ConstantWeight;
- }
return llvm::InlineCost::get(Cost);
}
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