RealtimeSanitizer.cpp

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//===- RealtimeSanitizer.cpp - RealtimeSanitizer instrumentation *- 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 is a part of the RealtimeSanitizer, an LLVM transformation for
// detecting and reporting realtime safety violations.
//
// See also: llvm-project/compiler-rt/lib/rtsan/
//
//===----------------------------------------------------------------------===//
 
#include "llvm/IR/Analysis.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
 
#include "llvm/Transforms/Instrumentation/RealtimeSanitizer.h"
 
using namespace llvm;
 
static void insertCallBeforeInstruction(Function &Fn, Instruction &Instruction,
                                        const char *FunctionName) {
  LLVMContext &Context = Fn.getContext();
  FunctionType *FuncType = FunctionType::get(Type::getVoidTy(Context), false);
  FunctionCallee Func =
      Fn.getParent()->getOrInsertFunction(FunctionName, FuncType);
  IRBuilder<> Builder{&Instruction};
  Builder.CreateCall(Func, {});
}
 
static void insertCallAtFunctionEntryPoint(Function &Fn,
                                           const char *InsertFnName) {
 
  insertCallBeforeInstruction(Fn, Fn.front().front(), InsertFnName);
}
 
static void insertCallAtAllFunctionExitPoints(Function &Fn,
                                              const char *InsertFnName) {
  for (auto &BB : Fn)
    for (auto &I : BB)
      if (isa<ReturnInst>(&I))
        insertCallBeforeInstruction(Fn, I, InsertFnName);
}
 
RealtimeSanitizerPass::RealtimeSanitizerPass(
    const RealtimeSanitizerOptions &Options) {}
 
PreservedAnalyses RealtimeSanitizerPass::run(Function &F,
                                             AnalysisManager<Function> &AM) {
  if (F.hasFnAttribute(Attribute::SanitizeRealtime)) {
    insertCallAtFunctionEntryPoint(F, "__rtsan_realtime_enter");
    insertCallAtAllFunctionExitPoints(F, "__rtsan_realtime_exit");
 
    PreservedAnalyses PA;
    PA.preserveSet<CFGAnalyses>();
    return PA;
  }
 
  return PreservedAnalyses::all();
}