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Diffstat (limited to 'cmake/workaround_llvm_pr39177.cmake')
-rw-r--r-- | cmake/workaround_llvm_pr39177.cmake | 133 |
1 files changed, 0 insertions, 133 deletions
diff --git a/cmake/workaround_llvm_pr39177.cmake b/cmake/workaround_llvm_pr39177.cmake deleted file mode 100644 index 9e0ac8bd..00000000 --- a/cmake/workaround_llvm_pr39177.cmake +++ /dev/null @@ -1,133 +0,0 @@ -# Workaround for LLVM PR39177 -# - https://bugs.llvm.org/show_bug.cgi?id=39177 -# - https://github.com/klee/klee/issues/1000 -# -# TODO: remove when support for LLVM <= 7 is dropped -# -# Short description of the bug: -# The LLVM pass `-instcombine` optimizes calls to C standard lib functions by, -# e.g. transforming the following call to a call to fwrite(): -# fprintf(stderr, "hello world!\n"); -# In uClibc, and thus klee-uclibc, fwrite() is defined as an alias to a function -# fwrite_unlocked(). This translates to a GlobalAlias in LLVM IR. When trying to -# infer function attributes from fwrite(), LLVM tries to cast a GlobalAlias to a -# Function, which results in a null-pointer dereference. When calling KLEE with -# `-optimize`, this leads to a crash of KLEE. -# -# This bug affects LLVM 3.9 - 7.0.0. -# -# As the bug results in a null-pointer dereference when trying to access a -# Function that is only available as GlobalAlias, this workaround introduces a -# pass into KLEE that replaces aliases for certain C standard lib function with -# clones of the corresponding aliasee function. -# -# The bug was fixed in the following commits in LLVM: -# - https://reviews.llvm.org/rL344454 -# - https://reviews.llvm.org/rL344455 -# - https://reviews.llvm.org/rL344645 -# These patches were then applied to the release_70 branch to land in 7.0.1: -# - https://reviews.llvm.org/rL345921 -# -# This CMake file checks whether the method responsible for the null-pointer -# dereference leads to a crash of the program given in this file. -# -# Files that were created/modified for this workaround: -# [NEW FILE] cmake/workaround_llvm_pr39177.cmake (this file) -# [NEW FILE] cmake/workaround_llvm_pr39177.ll (auxiliary file for feature test) -# [NEW FILE] lib/Module/WorkaroundLLVMPR39177.cpp -# -# [MODIFIED] CMakeLists.txt (including this file) -# [MODIFIED] include/klee/Config/config.h.cmin (cmakedefine) -# [MODIFIED] lib/Module/CMakeLists.txt -# [MODIFIED] lib/Module/Optimize.cpp (add pass during optimization) -# [MODIFIED] lib/Module/Passes.h - -# Detect whether LLVM version is affected by PR39177 -if (${LLVM_VERSION_MAJOR} LESS 7 OR (${LLVM_VERSION_MAJOR} EQUAL 7 AND ${LLVM_VERSION_MINOR} EQUAL 0 AND ${LLVM_VERSION_PATCH} EQUAL 0)) # LLVM <= 7.0.0 - set(DISABLE_WORKAROUND_LLVM_PR39177_DEFAULT OFF) -else() - set(DISABLE_WORKAROUND_LLVM_PR39177_DEFAULT ON) -endif() - -option(DISABLE_WORKAROUND_LLVM_PR39177 "Disable Workaround for LLVM PR39177 (affecting LLVM 3.9 - 7.0.0)" ${DISABLE_WORKAROUND_LLVM_PR39177_DEFAULT}) - -if (NOT DISABLE_WORKAROUND_LLVM_PR39177) - # Detect whether PR39177 leads to crash - include(CheckCXXSourceRuns) - - cmake_push_check_state() - klee_get_llvm_libs(LLVM_LIBS asmparser transformutils) - set(CMAKE_REQUIRED_INCLUDES "${LLVM_INCLUDE_DIRS}") - set(CMAKE_REQUIRED_LIBRARIES "${LLVM_LIBS}") - - check_cxx_source_runs(" - #include \"llvm/Analysis/TargetLibraryInfo.h\" - #include \"llvm/AsmParser/Parser.h\" - #include \"llvm/AsmParser/SlotMapping.h\" - #include \"llvm/IR/ConstantFolder.h\" - #include \"llvm/IR/Constants.h\" - #include \"llvm/IR/DataLayout.h\" - #include \"llvm/IR/DiagnosticInfo.h\" - #include \"llvm/IR/Instructions.h\" - #include \"llvm/IR/IRBuilder.h\" - #include \"llvm/IR/LLVMContext.h\" - #include \"llvm/Transforms/Utils/BuildLibCalls.h\" - - #include <signal.h> - - void handler(int, siginfo_t*, void*) { - // program received SIGSEGV - exit(1); - } - - using namespace llvm; - - int main() { - // capture segfault - struct sigaction action; - memset(&action, 0, sizeof(struct sigaction)); - action.sa_flags = SA_SIGINFO; - action.sa_sigaction = handler; - sigaction(SIGSEGV, &action, NULL); - - // setup test - LLVMContext Ctx; - SMDiagnostic Error; - SlotMapping Mapping; - auto M = llvm::parseAssemblyFile(\"${CMAKE_SOURCE_DIR}/cmake/workaround_llvm_pr39177.ll\", Error, Ctx, &Mapping); - if (!M) { - Error.print(\"AssemblyString\", llvm::errs()); - return -1; - } - - auto *F = M->getFunction(\"test\"); - auto *CI = cast<CallInst>(&*std::next(F->begin()->begin())); - auto &DL = M->getDataLayout(); - Value *Size = ConstantInt::get(DL.getIntPtrType(Ctx), 8); - ConstantFolder CF; - IRBuilder<> B(&*F->begin(), CF); - TargetLibraryInfo TLI = TargetLibraryInfoWrapperPass({\"x86_64\", \"\", \"linux-gnu\"}).getTLI(); - - // test if this call produces segfault - emitFWrite(CI->getArgOperand(1), Size, CI->getArgOperand(0), B, DL, &TLI); - - return 0; - }" - LLVM_PR39177_FIXED - ) - cmake_pop_check_state() - - if (NOT LLVM_PR39177_FIXED) - message(STATUS "Workaround for LLVM PR39177 (affecting LLVM 3.9 - 7.0.0) enabled") - set(USE_WORKAROUND_LLVM_PR39177 1) # For config.h - else() - message(FATAL_ERROR "DISABLE_WORKAROUND_LLVM_PR39177 is not set to true" - "but crash resulting from PR39177 could not be detected." - "You may try to disable the workaround using" - "-DDISABLE_WORKAROUND_LLVM_PR39177=1 if you believe the issue is patched" - "in your version of LLVM.") - endif() -else() - message(STATUS "Workaround for LLVM PR39177 (affecting LLVM 3.9 - 7.0.0) disabled") - unset(USE_WORKAROUND_LLVM_PR39177) # For config.h -endif() |