- /// \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;
-
- /// \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);
- }
-
- /// \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(); }
-
- /// \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(); }
- };