blob: 04b39c17694677827301fb16bd2cff88ddcd9b82 [file] [log] [blame]
//===- CodeMetrics.h - Code cost measurements -------------------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file implements various weight measurements for code, helping
// the Inliner and other passes decide whether to duplicate its contents.
#include "llvm/ADT/DenseMap.h"
#include "llvm/IR/CallSite.h"
namespace llvm {
class BasicBlock;
class Function;
class Instruction;
class DataLayout;
class TargetTransformInfo;
class Value;
/// \brief Check whether a call will lower to something small.
/// This tests checks whether this callsite will lower to something
/// significantly cheaper than a traditional call, often a single
/// instruction. Note that if isInstructionFree(CS.getInstruction()) would
/// return true, so will this function.
bool callIsSmall(ImmutableCallSite CS);
/// \brief Utility to calculate the size and a few similar metrics for a set
/// of basic blocks.
struct CodeMetrics {
/// \brief True if this function contains a call to setjmp or other functions
/// with attribute "returns twice" without having the attribute itself.
bool exposesReturnsTwice;
/// \brief True if this function calls itself.
bool isRecursive;
/// \brief True if this function cannot be duplicated.
/// True if this function contains one or more indirect branches, or it contains
/// one or more 'noduplicate' instructions.
bool notDuplicatable;
/// \brief True if this function calls alloca (in the C sense).
bool usesDynamicAlloca;
/// \brief Number of instructions in the analyzed blocks.
unsigned NumInsts;
/// \brief Number of analyzed blocks.
unsigned NumBlocks;
/// \brief Keeps track of basic block code size estimates.
DenseMap<const BasicBlock *, unsigned> NumBBInsts;
/// \brief Keep track of the number of calls to 'big' functions.
unsigned NumCalls;
/// \brief The number of calls to internal functions with a single caller.
/// These are likely targets for future inlining, likely exposed by
/// interleaved devirtualization.
unsigned NumInlineCandidates;
/// \brief How many instructions produce vector values.
/// The inliner is more aggressive with inlining vector kernels.
unsigned NumVectorInsts;
/// \brief How many 'ret' instructions the blocks contain.
unsigned NumRets;
: exposesReturnsTwice(false), isRecursive(false), notDuplicatable(false),
usesDynamicAlloca(false), NumInsts(0), NumBlocks(0), NumCalls(0),
NumInlineCandidates(0), NumVectorInsts(0), NumRets(0) {}
/// \brief Add information about a block to the current state.
void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI);