Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- Transforms/Instrumentation.h - Instrumentation passes ----*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file defines constructor functions for instrumentation passes.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_TRANSFORMS_INSTRUMENTATION_H

#define LLVM_TRANSFORMS_INSTRUMENTATION_H

#include "llvm/ADT/StringRef.h"

#include "llvm/IR/BasicBlock.h"

#include "llvm/IR/DebugInfoMetadata.h"

#include "llvm/IR/Function.h"

#include "llvm/IR/IRBuilder.h"

#include "llvm/IR/Instruction.h"

#include <cassert>

#include <cstdint>

#include <limits>

#include <string>

#include <vector>

namespace llvm {

class Triple;

class OptimizationRemarkEmitter;

class Comdat;

class CallBase;

/// Instrumentation passes often insert conditional checks into entry blocks.

/// Call this function before splitting the entry block to move instructions

/// that must remain in the entry block up before the split point. Static

/// allocas and llvm.localescape calls, for example, must remain in the entry

/// block.

BasicBlock::iterator PrepareToSplitEntryBlock(BasicBlock &BB,

                                              BasicBlock::iterator IP);

// Create a constant for Str so that we can pass it to the run-time lib.

GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,

                                             bool AllowMerging,

                                             const char *NamePrefix = "");

// Returns F.getComdat() if it exists.

// Otherwise creates a new comdat, sets F's comdat, and returns it.

// Returns nullptr on failure.

Comdat *getOrCreateFunctionComdat(Function &F, Triple &T);

// Insert GCOV profiling instrumentation

struct GCOVOptions {

  static GCOVOptions getDefault();

  // Specify whether to emit .gcno files.

  bool EmitNotes;

  // Specify whether to modify the program to emit .gcda files when run.

  bool EmitData;

  // A four-byte version string. The meaning of a version string is described in

  // gcc's gcov-io.h

  char Version[4];

  // Add the 'noredzone' attribute to added runtime library calls.

  bool NoRedZone;

  // Use atomic profile counter increments.

  bool Atomic = false;

  // Regexes separated by a semi-colon to filter the files to instrument.

  std::string Filter;

  // Regexes separated by a semi-colon to filter the files to not instrument.

  std::string Exclude;

};

// The pgo-specific indirect call promotion function declared below is used by

// the pgo-driven indirect call promotion and sample profile passes. It's a

// wrapper around llvm::promoteCall, et al. that additionally computes !prof

// metadata. We place it in a pgo namespace so it's not confused with the

// generic utilities.

namespace pgo {

// Helper function that transforms CB (either an indirect-call instruction, or

// an invoke instruction , to a conditional call to F. This is like:

//     if (Inst.CalledValue == F)

//        F(...);

//     else

//        Inst(...);

//     end

// TotalCount is the profile count value that the instruction executes.

// Count is the profile count value that F is the target function.

// These two values are used to update the branch weight.

// If \p AttachProfToDirectCall is true, a prof metadata is attached to the

// new direct call to contain \p Count.

// Returns the promoted direct call instruction.

CallBase &promoteIndirectCall(CallBase &CB, Function *F, uint64_t Count,

                              uint64_t TotalCount, bool AttachProfToDirectCall,

                              OptimizationRemarkEmitter *ORE);

} // namespace pgo

/// Options for the frontend instrumentation based profiling pass.

struct InstrProfOptions {

  // Add the 'noredzone' attribute to added runtime library calls.

  bool NoRedZone = false;

  // Do counter register promotion

  bool DoCounterPromotion = false;

  // Use atomic profile counter increments.

  bool Atomic = false;

  // Use BFI to guide register promotion

  bool UseBFIInPromotion = false;

  // Name of the profile file to use as output

  std::string InstrProfileOutput;

  InstrProfOptions() = default;

};

// Options for sanitizer coverage instrumentation.

struct SanitizerCoverageOptions {

  enum Type {

    SCK_None = 0,

    SCK_Function,

    SCK_BB,

    SCK_Edge

  } CoverageType = SCK_None;

  bool IndirectCalls = false;

  bool TraceBB = false;

  bool TraceCmp = false;

  bool TraceDiv = false;

  bool TraceGep = false;

  bool Use8bitCounters = false;

  bool TracePC = false;

  bool TracePCGuard = false;

  bool Inline8bitCounters = false;

  bool InlineBoolFlag = false;

  bool PCTable = false;

  bool NoPrune = false;

  bool StackDepth = false;

  bool TraceLoads = false;

  bool TraceStores = false;

  bool CollectControlFlow = false;

  SanitizerCoverageOptions() = default;

};

/// Calculate what to divide by to scale counts.

///

/// Given the maximum count, calculate a divisor that will scale all the

/// weights to strictly less than std::numeric_limits<uint32_t>::max().

static inline uint64_t calculateCountScale(uint64_t MaxCount) {

  return MaxCount < std::numeric_limits<uint32_t>::max()

             ? 1

             : MaxCount / std::numeric_limits<uint32_t>::max() + 1;

}

/// Scale an individual branch count.

///

/// Scale a 64-bit weight down to 32-bits using \c Scale.

///

static inline uint32_t scaleBranchCount(uint64_t Count, uint64_t Scale) {

  uint64_t Scaled = Count / Scale;

  assert(Scaled <= std::numeric_limits<uint32_t>::max() && "overflow 32-bits");

  return Scaled;

}

// Use to ensure the inserted instrumentation has a DebugLocation; if none is

// attached to the source instruction, try to use a DILocation with offset 0

// scoped to surrounding function (if it has a DebugLocation).

//

// Some non-call instructions may be missing debug info, but when inserting

// instrumentation calls, some builds (e.g. LTO) want calls to have debug info

// if the enclosing function does.

struct InstrumentationIRBuilder : IRBuilder<> {

  static void ensureDebugInfo(IRBuilder<> &IRB, const Function &F) {

    if (IRB.getCurrentDebugLocation())

      return;

    if (DISubprogram *SP = F.getSubprogram())

      IRB.SetCurrentDebugLocation(DILocation::get(SP->getContext(), 0, 0, SP));

  }

  explicit InstrumentationIRBuilder(Instruction *IP) : IRBuilder<>(IP) {

    ensureDebugInfo(*this, *IP->getFunction());

  }

};

} // end namespace llvm

#endif // LLVM_TRANSFORMS_INSTRUMENTATION_H