#ifndef LLVM_ANALYSIS_INLINECOST_H
#define LLVM_ANALYSIS_INLINECOST_H
-#include <cassert>
-#include <climits>
-#include <vector>
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/ValueMap.h"
#include "llvm/Analysis/CodeMetrics.h"
+#include "llvm/Function.h"
+#include <cassert>
+#include <climits>
+#include <vector>
namespace llvm {
- class Value;
- class Function;
- class BasicBlock;
class CallSite;
- template<class PtrType, unsigned SmallSize>
- class SmallPtrSet;
+ class DataLayout;
namespace InlineConstants {
// Various magic constants used to adjust heuristics.
const int InstrCost = 5;
- const int IndirectCallBonus = 500;
+ const int IndirectCallThreshold = 100;
const int CallPenalty = 25;
const int LastCallToStaticBonus = -15000;
const int ColdccPenalty = 2000;
const int NoreturnPenalty = 10000;
+ /// Do not inline functions which allocate this many bytes on the stack
+ /// when the caller is recursive.
+ const unsigned TotalAllocaSizeRecursiveCaller = 1024;
}
- /// InlineCost - Represent the cost of inlining a function. This
- /// supports special values for functions which should "always" or
- /// "never" be inlined. Otherwise, the cost represents a unitless
- /// amount; smaller values increase the likelyhood of the function
- /// being inlined.
+ /// \brief Represents the cost of inlining a function.
+ ///
+ /// This supports special values for functions which should "always" or
+ /// "never" be inlined. Otherwise, the cost represents a unitless amount;
+ /// smaller values increase the likelihood of the function being inlined.
+ ///
+ /// Objects of this type also provide the adjusted threshold for inlining
+ /// based on the information available for a particular callsite. They can be
+ /// directly tested to determine if inlining should occur given the cost and
+ /// threshold for this cost metric.
class InlineCost {
- enum Kind {
- Value,
- Always,
- Never
+ enum SentinelValues {
+ AlwaysInlineCost = INT_MIN,
+ NeverInlineCost = INT_MAX
};
- // This is a do-it-yourself implementation of
- // int Cost : 30;
- // unsigned Type : 2;
- // We used to use bitfields, but they were sometimes miscompiled (PR3822).
- enum { TYPE_BITS = 2 };
- enum { COST_BITS = unsigned(sizeof(unsigned)) * CHAR_BIT - TYPE_BITS };
- unsigned TypedCost; // int Cost : COST_BITS; unsigned Type : TYPE_BITS;
+ /// \brief The estimated cost of inlining this callsite.
+ const int Cost;
- Kind getType() const {
- return Kind(TypedCost >> COST_BITS);
- }
+ /// \brief The adjusted threshold against which this cost was computed.
+ const int Threshold;
- int getCost() const {
- // Sign-extend the bottom COST_BITS bits.
- return (int(TypedCost << TYPE_BITS)) >> TYPE_BITS;
- }
+ // Trivial constructor, interesting logic in the factory functions below.
+ InlineCost(int Cost, int Threshold)
+ : Cost(Cost), Threshold(Threshold) {}
- InlineCost(int C, int T) {
- TypedCost = (unsigned(C << TYPE_BITS) >> TYPE_BITS) | (T << COST_BITS);
- assert(getCost() == C && "Cost exceeds InlineCost precision");
- }
public:
- static InlineCost get(int Cost) { return InlineCost(Cost, Value); }
- static InlineCost getAlways() { return InlineCost(0, Always); }
- static InlineCost getNever() { return InlineCost(0, Never); }
-
- bool isVariable() const { return getType() == Value; }
- bool isAlways() const { return getType() == Always; }
- bool isNever() const { return getType() == Never; }
-
- /// getValue() - Return a "variable" inline cost's amount. It is
- /// an error to call this on an "always" or "never" InlineCost.
- int getValue() const {
- assert(getType() == Value && "Invalid access of InlineCost");
- return getCost();
+ static InlineCost get(int Cost, int Threshold) {
+ assert(Cost > AlwaysInlineCost && "Cost crosses sentinel value");
+ assert(Cost < NeverInlineCost && "Cost crosses sentinel value");
+ return InlineCost(Cost, Threshold);
+ }
+ static InlineCost getAlways() {
+ return InlineCost(AlwaysInlineCost, 0);
+ }
+ static InlineCost getNever() {
+ return InlineCost(NeverInlineCost, 0);
}
- };
-
- /// InlineCostAnalyzer - Cost analyzer used by inliner.
- class InlineCostAnalyzer {
- struct ArgInfo {
- public:
- unsigned ConstantWeight;
- unsigned AllocaWeight;
- unsigned ConstantBonus;
-
- ArgInfo(unsigned CWeight, unsigned AWeight, unsigned CBonus)
- : ConstantWeight(CWeight), AllocaWeight(AWeight), ConstantBonus(CBonus)
- {}
- };
-
- struct FunctionInfo {
- CodeMetrics Metrics;
-
- /// ArgumentWeights - Each formal argument of the function is inspected to
- /// see if it is used in any contexts where making it a constant or alloca
- /// would reduce the code size. If so, we add some value to the argument
- /// entry here.
- std::vector<ArgInfo> ArgumentWeights;
+ /// \brief Test whether the inline cost is low enough for inlining.
+ operator bool() const {
+ return Cost < Threshold;
+ }
+ bool isAlways() const { return Cost == AlwaysInlineCost; }
+ bool isNever() const { return Cost == NeverInlineCost; }
+ bool isVariable() const { return !isAlways() && !isNever(); }
- /// analyzeFunction - Add information about the specified function
- /// to the current structure.
- void analyzeFunction(Function *F);
+ /// \brief Get the inline cost estimate.
+ /// It is an error to call this on an "always" or "never" InlineCost.
+ int getCost() const {
+ assert(isVariable() && "Invalid access of InlineCost");
+ return Cost;
+ }
- /// NeverInline - Returns true if the function should never be
- /// inlined into any caller.
- bool NeverInline();
- };
+ /// \brief Get the cost delta from the threshold for inlining.
+ /// Only valid if the cost is of the variable kind. Returns a negative
+ /// value if the cost is too high to inline.
+ int getCostDelta() const { return Threshold - getCost(); }
+ };
- // The Function* for a function can be changed (by ArgumentPromotion);
- // the ValueMap will update itself when this happens.
- ValueMap<const Function *, FunctionInfo> CachedFunctionInfo;
+ /// InlineCostAnalyzer - Cost analyzer used by inliner.
+ class InlineCostAnalyzer {
+ // DataLayout if available, or null.
+ const DataLayout *TD;
public:
+ InlineCostAnalyzer(): TD(0) {}
- /// getInlineCost - The heuristic used to determine if we should inline the
- /// function call or not.
- ///
- InlineCost getInlineCost(CallSite CS,
- SmallPtrSet<const Function *, 16> &NeverInline);
- /// getCalledFunction - The heuristic used to determine if we should inline
- /// the function call or not. The callee is explicitly specified, to allow
- /// you to calculate the cost of inlining a function via a pointer. The
- /// result assumes that the inlined version will always be used. You should
- /// weight it yourself in cases where this callee will not always be called.
- InlineCost getInlineCost(CallSite CS,
- Function *Callee,
- SmallPtrSet<const Function *, 16> &NeverInline);
-
- /// getSpecializationBonus - The heuristic used to determine the per-call
- /// performance boost for using a specialization of Callee with argument
- /// SpecializedArgNos replaced by a constant.
- int getSpecializationBonus(Function *Callee,
- SmallVectorImpl<unsigned> &SpecializedArgNo);
-
- /// getSpecializationCost - The heuristic used to determine the code-size
- /// impact of creating a specialized version of Callee with argument
- /// SpecializedArgNo replaced by a constant.
- InlineCost getSpecializationCost(Function *Callee,
- SmallVectorImpl<unsigned> &SpecializedArgNo);
-
- /// getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a
- /// higher threshold to determine if the function call should be inlined.
- float getInlineFudgeFactor(CallSite CS);
-
- /// resetCachedFunctionInfo - erase any cached cost info for this function.
- void resetCachedCostInfo(Function* Caller) {
- CachedFunctionInfo[Caller] = FunctionInfo();
- }
+ void setDataLayout(const DataLayout *TData) { TD = TData; }
- /// growCachedCostInfo - update the cached cost info for Caller after Callee
- /// has been inlined. If Callee is NULL it means a dead call has been
- /// eliminated.
- void growCachedCostInfo(Function* Caller, Function* Callee);
-
- /// clear - empty the cache of inline costs
- void clear();
+ /// \brief Get an InlineCost object representing the cost of inlining this
+ /// callsite.
+ ///
+ /// Note that threshold is passed into this function. Only costs below the
+ /// threshold are computed with any accuracy. The threshold can be used to
+ /// bound the computation necessary to determine whether the cost is
+ /// sufficiently low to warrant inlining.
+ InlineCost getInlineCost(CallSite CS, int Threshold);
+
+ /// \brief Get an InlineCost with the callee explicitly specified.
+ /// This allows you to calculate the cost of inlining a function via a
+ /// pointer. This behaves exactly as the version with no explicit callee
+ /// parameter in all other respects.
+ //
+ // Note: This is used by out-of-tree passes, please do not remove without
+ // adding a replacement API.
+ InlineCost getInlineCost(CallSite CS, Function *Callee, int Threshold);
+
+ /// \brief Minimal filter to detect invalid constructs for inlining.
+ bool isInlineViable(Function &Callee);
};
-
- /// callIsSmall - If a call is likely to lower to a single target instruction,
- /// or is otherwise deemed small return true.
- bool callIsSmall(const Function *Callee);
}
#endif
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