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       1             : //===- CodeMetrics.h - Code cost measurements -------------------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // This file implements various weight measurements for code, helping
      11             : // the Inliner and other passes decide whether to duplicate its contents.
      12             : //
      13             : //===----------------------------------------------------------------------===//
      14             : 
      15             : #ifndef LLVM_ANALYSIS_CODEMETRICS_H
      16             : #define LLVM_ANALYSIS_CODEMETRICS_H
      17             : 
      18             : #include "llvm/ADT/DenseMap.h"
      19             : #include "llvm/ADT/SmallPtrSet.h"
      20             : #include "llvm/IR/CallSite.h"
      21             : 
      22             : namespace llvm {
      23             : class AssumptionCache;
      24             : class BasicBlock;
      25             : class Loop;
      26             : class Function;
      27             : class Instruction;
      28             : class DataLayout;
      29             : class TargetTransformInfo;
      30             : class Value;
      31             : 
      32             : /// Check whether a call will lower to something small.
      33             : ///
      34             : /// This tests checks whether this callsite will lower to something
      35             : /// significantly cheaper than a traditional call, often a single
      36             : /// instruction. Note that if isInstructionFree(CS.getInstruction()) would
      37             : /// return true, so will this function.
      38             : bool callIsSmall(ImmutableCallSite CS);
      39             : 
      40             : /// Utility to calculate the size and a few similar metrics for a set
      41             : /// of basic blocks.
      42       25875 : struct CodeMetrics {
      43             :   /// True if this function contains a call to setjmp or other functions
      44             :   /// with attribute "returns twice" without having the attribute itself.
      45             :   bool exposesReturnsTwice = false;
      46             : 
      47             :   /// True if this function calls itself.
      48             :   bool isRecursive = false;
      49             : 
      50             :   /// True if this function cannot be duplicated.
      51             :   ///
      52             :   /// True if this function contains one or more indirect branches, or it contains
      53             :   /// one or more 'noduplicate' instructions.
      54             :   bool notDuplicatable = false;
      55             : 
      56             :   /// True if this function contains a call to a convergent function.
      57             :   bool convergent = false;
      58             : 
      59             :   /// True if this function calls alloca (in the C sense).
      60             :   bool usesDynamicAlloca = false;
      61             : 
      62             :   /// Number of instructions in the analyzed blocks.
      63             :   unsigned NumInsts = false;
      64             : 
      65             :   /// Number of analyzed blocks.
      66             :   unsigned NumBlocks = false;
      67             : 
      68             :   /// Keeps track of basic block code size estimates.
      69             :   DenseMap<const BasicBlock *, unsigned> NumBBInsts;
      70             : 
      71             :   /// Keep track of the number of calls to 'big' functions.
      72             :   unsigned NumCalls = false;
      73             : 
      74             :   /// The number of calls to internal functions with a single caller.
      75             :   ///
      76             :   /// These are likely targets for future inlining, likely exposed by
      77             :   /// interleaved devirtualization.
      78             :   unsigned NumInlineCandidates = 0;
      79             : 
      80             :   /// How many instructions produce vector values.
      81             :   ///
      82             :   /// The inliner is more aggressive with inlining vector kernels.
      83             :   unsigned NumVectorInsts = 0;
      84             : 
      85             :   /// How many 'ret' instructions the blocks contain.
      86             :   unsigned NumRets = 0;
      87             : 
      88             :   /// Add information about a block to the current state.
      89             :   void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI,
      90             :                          const SmallPtrSetImpl<const Value*> &EphValues);
      91             : 
      92             :   /// Collect a loop's ephemeral values (those used only by an assume
      93             :   /// or similar intrinsics in the loop).
      94             :   static void collectEphemeralValues(const Loop *L, AssumptionCache *AC,
      95             :                                      SmallPtrSetImpl<const Value *> &EphValues);
      96             : 
      97             :   /// Collect a functions's ephemeral values (those used only by an
      98             :   /// assume or similar intrinsics in the function).
      99             :   static void collectEphemeralValues(const Function *L, AssumptionCache *AC,
     100             :                                      SmallPtrSetImpl<const Value *> &EphValues);
     101             : };
     102             : 
     103             : }
     104             : 
     105             : #endif