- /// 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.
- 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();
- }
- };
-
- /// 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;
-
- /// CountCodeReductionForConstant - Figure out an approximation for how
- /// many instructions will be constant folded if the specified value is
- /// constant.
- unsigned CountCodeReductionForConstant(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(Value *V);
-
- /// analyzeFunction - Add information about the specified function
- /// to the current structure.
- void analyzeFunction(Function *F);
- };
-
- // The Function* for a function can be changed (by ArgumentPromotion);
- // the ValueMap will update itself when this happens.
- ValueMap<const Function *, FunctionInfo> CachedFunctionInfo;
-
- public:
-
- /// getInlineCost - The heuristic used to determine if we should inline the
- /// function call or not.
- ///
- InlineCost getInlineCost(CallSite CS,
- SmallPtrSet<const Function *, 16> &NeverInline);
-
- /// 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);
- };
+ /// \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);