X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FAnalysis%2FInlineCost.h;h=515cbce345781e6072b9d9677037f1ccddf83ec4;hb=b09c146b116359616f6cbd4c8b3328607e00ff42;hp=a138fc41e95ebb07b8c18a1e8fcc6dd4d4c350f1;hpb=0f13bc8c23f93b5c84a71d60a8dff0142a769224;p=oota-llvm.git diff --git a/include/llvm/Analysis/InlineCost.h b/include/llvm/Analysis/InlineCost.h index a138fc41e95..515cbce3457 100644 --- a/include/llvm/Analysis/InlineCost.h +++ b/include/llvm/Analysis/InlineCost.h @@ -14,166 +14,125 @@ #ifndef LLVM_ANALYSIS_INLINECOST_H #define LLVM_ANALYSIS_INLINECOST_H -#include -#include -#include #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 +#include +#include namespace llvm { - class Value; - class Function; - class BasicBlock; class CallSite; - template - 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; + /// \brief Test whether the inline cost is low enough for inlining. + operator bool() const { + return Cost < Threshold; + } - /// 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 ArgumentWeights; + 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 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 &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 &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 &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 &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