#ifndef LLVM_ANALYSIS_INLINECOST_H
#define LLVM_ANALYSIS_INLINECOST_H
-#include "llvm/Function.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/ValueMap.h"
-#include "llvm/Analysis/CodeMetrics.h"
+#include "llvm/Analysis/CallGraphSCCPass.h"
#include <cassert>
#include <climits>
-#include <vector>
namespace llvm {
+class AssumptionCacheTracker;
+class CallSite;
+class DataLayout;
+class Function;
+class TargetTransformInfo;
+
+namespace InlineConstants {
+ // Various magic constants used to adjust heuristics.
+ const int InstrCost = 5;
+ 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;
+}
+
+/// \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 SentinelValues {
+ AlwaysInlineCost = INT_MIN,
+ NeverInlineCost = INT_MAX
+ };
+
+ /// \brief The estimated cost of inlining this callsite.
+ const int Cost;
- class CallSite;
- template<class PtrType, unsigned SmallSize>
- class SmallPtrSet;
- class TargetData;
-
- namespace InlineConstants {
- // Various magic constants used to adjust heuristics.
- const int InstrCost = 5;
- const int IndirectCallBonus = -100;
- const int CallPenalty = 25;
- const int LastCallToStaticBonus = -15000;
- const int ColdccPenalty = 2000;
- const int NoreturnPenalty = 10000;
+ /// \brief The adjusted threshold against which this cost was computed.
+ const int Threshold;
+
+ // Trivial constructor, interesting logic in the factory functions below.
+ InlineCost(int Cost, int Threshold) : Cost(Cost), Threshold(Threshold) {}
+
+public:
+ 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);
}
- /// 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 likelihood of the function
- /// being inlined.
- class InlineCost {
- enum Kind {
- Value,
- Always,
- Never
- };
-
- // 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;
-
- Kind getType() const {
- return Kind(TypedCost >> COST_BITS);
- }
-
- int getCost() const {
- // Sign-extend the bottom COST_BITS bits.
- return (int(TypedCost << TYPE_BITS)) >> TYPE_BITS;
- }
-
- 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();
- }
- };
+ /// \brief Test whether the inline cost is low enough for inlining.
+ explicit operator bool() const {
+ return Cost < Threshold;
+ }
- /// InlineCostAnalyzer - Cost analyzer used by inliner.
- class InlineCostAnalyzer {
- struct ArgInfo {
- public:
- unsigned ConstantWeight;
- unsigned AllocaWeight;
-
- ArgInfo(unsigned CWeight, unsigned AWeight)
- : ConstantWeight(CWeight), AllocaWeight(AWeight)
- {}
- };
-
- 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;
-
- /// PointerArgPairWeights - Weights to use when giving an inline bonus to
- /// a call site due to correlated pairs of pointers.
- DenseMap<std::pair<unsigned, unsigned>, unsigned> PointerArgPairWeights;
-
- /// countCodeReductionForConstant - Figure out an approximation for how
- /// many instructions will be constant folded if the specified value is
- /// constant.
- unsigned countCodeReductionForConstant(const CodeMetrics &Metrics,
- Value *V);
-
- /// countCodeReductionForAlloca - Figure out an approximation of how much
- /// smaller the function will be if it is inlined into a context where an
- /// argument becomes an alloca.
- unsigned countCodeReductionForAlloca(const CodeMetrics &Metrics,
- Value *V);
-
- /// countCodeReductionForPointerPair - Count the bonus to apply to an
- /// inline call site where a pair of arguments are pointers and one
- /// argument is a constant offset from the other. The idea is to
- /// recognize a common C++ idiom where a begin and end iterator are
- /// actually pointers, and many operations on the pair of them will be
- /// constants if the function is called with arguments that have
- /// a constant offset.
- void countCodeReductionForPointerPair(
- const CodeMetrics &Metrics,
- DenseMap<Value *, unsigned> &PointerArgs,
- Value *V, unsigned ArgIdx);
-
- /// analyzeFunction - Add information about the specified function
- /// to the current structure.
- void analyzeFunction(Function *F, const TargetData *TD);
-
- /// NeverInline - Returns true if the function should never be
- /// inlined into any caller.
- bool NeverInline();
- };
-
- // The Function* for a function can be changed (by ArgumentPromotion);
- // the ValueMap will update itself when this happens.
- ValueMap<const Function *, FunctionInfo> CachedFunctionInfo;
-
- // TargetData if available, or null.
- const TargetData *TD;
-
- int CountBonusForConstant(Value *V, Constant *C = NULL);
- int ConstantFunctionBonus(CallSite CS, Constant *C);
- int getInlineSize(CallSite CS, Function *Callee);
- int getInlineBonuses(CallSite CS, Function *Callee);
- public:
- InlineCostAnalyzer(): TD(0) {}
-
- void setTargetData(const TargetData *TData) { TD = TData; }
-
- /// 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();
- }
-
- /// 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();
- };
+ bool isAlways() const { return Cost == AlwaysInlineCost; }
+ bool isNever() const { return Cost == NeverInlineCost; }
+ bool isVariable() const { return !isAlways() && !isNever(); }
+
+ /// \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;
+ }
+
+ /// \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(); }
+};
+
+/// \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.
+///
+/// Also note that calling this function *dynamically* computes the cost of
+/// inlining the callsite. It is an expensive, heavyweight call.
+InlineCost getInlineCost(CallSite CS, int Threshold,
+ TargetTransformInfo &CalleeTTI,
+ AssumptionCacheTracker *ACT);
+
+/// \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.
+//
+InlineCost getInlineCost(CallSite CS, Function *Callee, int Threshold,
+ TargetTransformInfo &CalleeTTI,
+ AssumptionCacheTracker *ACT);
- /// 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);
+/// \brief Minimal filter to detect invalid constructs for inlining.
+bool isInlineViable(Function &Callee);
}
#endif
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