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      1 //===- CodeMetrics.h - Code cost measurements -------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // This file implements various weight measurements for code, helping
     10 // the Inliner and other passes decide whether to duplicate its contents.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_ANALYSIS_CODEMETRICS_H
     15 #define LLVM_ANALYSIS_CODEMETRICS_H
     16 
     17 #include "llvm/ADT/DenseMap.h"
     18 
     19 namespace llvm {
     20 class AssumptionCache;
     21 class BasicBlock;
     22 class Loop;
     23 class Function;
     24 template <class T> class SmallPtrSetImpl;
     25 class TargetTransformInfo;
     26 class Value;
     27 
     28 /// Utility to calculate the size and a few similar metrics for a set
     29 /// of basic blocks.
     30 struct CodeMetrics {
     31   /// True if this function contains a call to setjmp or other functions
     32   /// with attribute "returns twice" without having the attribute itself.
     33   bool exposesReturnsTwice = false;
     34 
     35   /// True if this function calls itself.
     36   bool isRecursive = false;
     37 
     38   /// True if this function cannot be duplicated.
     39   ///
     40   /// True if this function contains one or more indirect branches, or it contains
     41   /// one or more 'noduplicate' instructions.
     42   bool notDuplicatable = false;
     43 
     44   /// True if this function contains a call to a convergent function.
     45   bool convergent = false;
     46 
     47   /// True if this function calls alloca (in the C sense).
     48   bool usesDynamicAlloca = false;
     49 
     50   /// Number of instructions in the analyzed blocks.
     51   unsigned NumInsts = false;
     52 
     53   /// Number of analyzed blocks.
     54   unsigned NumBlocks = false;
     55 
     56   /// Keeps track of basic block code size estimates.
     57   DenseMap<const BasicBlock *, unsigned> NumBBInsts;
     58 
     59   /// Keep track of the number of calls to 'big' functions.
     60   unsigned NumCalls = false;
     61 
     62   /// The number of calls to internal functions with a single caller.
     63   ///
     64   /// These are likely targets for future inlining, likely exposed by
     65   /// interleaved devirtualization.
     66   unsigned NumInlineCandidates = 0;
     67 
     68   /// How many instructions produce vector values.
     69   ///
     70   /// The inliner is more aggressive with inlining vector kernels.
     71   unsigned NumVectorInsts = 0;
     72 
     73   /// How many 'ret' instructions the blocks contain.
     74   unsigned NumRets = 0;
     75 
     76   /// Add information about a block to the current state.
     77   void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI,
     78                          const SmallPtrSetImpl<const Value *> &EphValues,
     79                          bool PrepareForLTO = false);
     80 
     81   /// Collect a loop's ephemeral values (those used only by an assume
     82   /// or similar intrinsics in the loop).
     83   static void collectEphemeralValues(const Loop *L, AssumptionCache *AC,
     84                                      SmallPtrSetImpl<const Value *> &EphValues);
     85 
     86   /// Collect a functions's ephemeral values (those used only by an
     87   /// assume or similar intrinsics in the function).
     88   static void collectEphemeralValues(const Function *L, AssumptionCache *AC,
     89                                      SmallPtrSetImpl<const Value *> &EphValues);
     90 };
     91 
     92 }
     93 
     94 #endif
     95