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//===-- WorkaroundLLVMPR39177.cpp -------------------------------*- C++ -*-===//
//
// The KLEE Symbolic Virtual Machine
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// This pass provides a workaround for LLVM bug PR39177 within the KLEE repo.
// For more information on this, please refer to the comments in
// cmake/workaround_llvm_pr39177.cmake
#include "Passes.h"
#include "klee/Support/ErrorHandling.h"
#include "llvm/Transforms/Utils/Cloning.h"
using namespace llvm;
namespace klee {
bool WorkaroundLLVMPR39177Pass::runOnModule(Module &M) {
bool modified = false;
const char *libfunctions[] = {
"strlen",
"strchr",
"strncmp",
"strcpy",
"strncpy",
"__memcpy_chk",
"memchr",
"memcmp",
"putchar",
"puts",
"fputc",
"fputc_unlocked",
"fputs",
"fputs_unlocked",
"fwrite",
"malloc",
"calloc",
"fwrite_unlocked",
"fgetc_unlocked",
"fgets_unlocked",
"fread_unlocked",
"memset_pattern16",
"fopen"
};
for (auto *funcname : libfunctions) {
if (M.getFunction(funcname) != nullptr)
continue;
GlobalValue *gv = M.getNamedValue(funcname);
auto *alias = dyn_cast_or_null<GlobalAlias>(gv);
if (alias == nullptr)
continue;
// get aliasee function if exists
while (auto *ga = dyn_cast<GlobalAlias>(alias->getAliasee())) {
assert(ga != alias && "alias pointing to itself");
alias = ga;
}
Function *f = dyn_cast<Function>(alias->getAliasee());
if (f == nullptr)
continue;
std::string aliasName = alias->getName().str();
// clone function
ValueToValueMapTy VMap;
Function *g = CloneFunction(f, VMap);
// replace alias with cloned function
alias->replaceAllUsesWith(g);
g->takeName(alias);
alias->eraseFromParent();
klee_message(
"WorkaroundLLVMPR39177: replaced alias @%s with clone of function @%s",
aliasName.c_str(), f->getName().str().c_str());
modified = true;
}
return modified;
}
char WorkaroundLLVMPR39177Pass::ID = 0;
} // namespace klee
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