include/llvm/Analysis/CodeMetrics.h

   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 #include "llvm/ADT/SmallPtrSet.h"
  19
  20 namespace llvm {
  21 class AssumptionCache;
  22 class BasicBlock;
  23 class Loop;
  24 class Function;
  25 class Instruction;
  26 class DataLayout;
  27 class TargetTransformInfo;
  28 class Value;
  29
  30 /// Utility to calculate the size and a few similar metrics for a set
  31 /// of basic blocks.
  32 struct CodeMetrics {
  33   /// True if this function contains a call to setjmp or other functions
  34   /// with attribute "returns twice" without having the attribute itself.
  35   bool exposesReturnsTwice = false;
  36
  37   /// True if this function calls itself.
  38   bool isRecursive = false;
  39
  40   /// True if this function cannot be duplicated.
  41   ///
  42   /// True if this function contains one or more indirect branches, or it contains
  43   /// one or more 'noduplicate' instructions.
  44   bool notDuplicatable = false;
  45
  46   /// True if this function contains a call to a convergent function.
  47   bool convergent = false;
  48
  49   /// True if this function calls alloca (in the C sense).
  50   bool usesDynamicAlloca = false;
  51
  52   /// Number of instructions in the analyzed blocks.
  53   unsigned NumInsts = false;
  54
  55   /// Number of analyzed blocks.
  56   unsigned NumBlocks = false;
  57
  58   /// Keeps track of basic block code size estimates.
  59   DenseMap<const BasicBlock *, unsigned> NumBBInsts;
  60
  61   /// Keep track of the number of calls to 'big' functions.
  62   unsigned NumCalls = false;
  63
  64   /// The number of calls to internal functions with a single caller.
  65   ///
  66   /// These are likely targets for future inlining, likely exposed by
  67   /// interleaved devirtualization.
  68   unsigned NumInlineCandidates = 0;
  69
  70   /// How many instructions produce vector values.
  71   ///
  72   /// The inliner is more aggressive with inlining vector kernels.
  73   unsigned NumVectorInsts = 0;
  74
  75   /// How many 'ret' instructions the blocks contain.
  76   unsigned NumRets = 0;
  77
  78   /// Add information about a block to the current state.
  79   void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI,
  80                          const SmallPtrSetImpl<const Value*> &EphValues);
  81
  82   /// Collect a loop's ephemeral values (those used only by an assume
  83   /// or similar intrinsics in the loop).
  84   static void collectEphemeralValues(const Loop *L, AssumptionCache *AC,
  85                                      SmallPtrSetImpl<const Value *> &EphValues);
  86
  87   /// Collect a functions's ephemeral values (those used only by an
  88   /// assume or similar intrinsics in the function).
  89   static void collectEphemeralValues(const Function *L, AssumptionCache *AC,
  90                                      SmallPtrSetImpl<const Value *> &EphValues);
  91 };
  92
  93 }
  94
  95 #endif