forked from OSchip/llvm-project
3334 lines
133 KiB
C++
3334 lines
133 KiB
C++
//===- AddressSanitizer.cpp - memory error detector -----------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of AddressSanitizer, an address sanity checker.
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// Details of the algorithm:
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// https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/Analysis/MemoryBuiltins.h"
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#include "llvm/Analysis/TargetLibraryInfo.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/BinaryFormat/MachO.h"
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#include "llvm/IR/Argument.h"
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#include "llvm/IR/Attributes.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/Comdat.h"
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#include "llvm/IR/Constant.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DIBuilder.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/DebugInfoMetadata.h"
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#include "llvm/IR/DebugLoc.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalAlias.h"
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#include "llvm/IR/GlobalValue.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/InlineAsm.h"
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#include "llvm/IR/InstVisitor.h"
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#include "llvm/IR/InstrTypes.h"
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#include "llvm/IR/Instruction.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/Metadata.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/Type.h"
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#include "llvm/IR/Use.h"
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#include "llvm/IR/Value.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/MC/MCSectionMachO.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Support/ScopedPrinter.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Transforms/Instrumentation.h"
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#include "llvm/Transforms/Utils/ASanStackFrameLayout.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/ModuleUtils.h"
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#include "llvm/Transforms/Utils/PromoteMemToReg.h"
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#include <algorithm>
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#include <cassert>
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#include <cstddef>
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#include <cstdint>
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#include <iomanip>
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#include <limits>
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#include <memory>
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#include <sstream>
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#include <string>
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#include <tuple>
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using namespace llvm;
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#define DEBUG_TYPE "asan"
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static const uint64_t kDefaultShadowScale = 3;
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static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
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static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
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static const uint64_t kDynamicShadowSentinel =
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std::numeric_limits<uint64_t>::max();
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static const uint64_t kSmallX86_64ShadowOffsetBase = 0x7FFFFFFF; // < 2G.
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static const uint64_t kSmallX86_64ShadowOffsetAlignMask = ~0xFFFULL;
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static const uint64_t kLinuxKasan_ShadowOffset64 = 0xdffffc0000000000;
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static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 44;
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static const uint64_t kSystemZ_ShadowOffset64 = 1ULL << 52;
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static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
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static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 37;
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static const uint64_t kAArch64_ShadowOffset64 = 1ULL << 36;
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static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
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static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
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static const uint64_t kNetBSD_ShadowOffset32 = 1ULL << 30;
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static const uint64_t kNetBSD_ShadowOffset64 = 1ULL << 46;
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static const uint64_t kNetBSDKasan_ShadowOffset64 = 0xdfff900000000000;
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static const uint64_t kPS4CPU_ShadowOffset64 = 1ULL << 40;
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static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
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static const uint64_t kEmscriptenShadowOffset = 0;
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static const uint64_t kMyriadShadowScale = 5;
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static const uint64_t kMyriadMemoryOffset32 = 0x80000000ULL;
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static const uint64_t kMyriadMemorySize32 = 0x20000000ULL;
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static const uint64_t kMyriadTagShift = 29;
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static const uint64_t kMyriadDDRTag = 4;
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static const uint64_t kMyriadCacheBitMask32 = 0x40000000ULL;
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// The shadow memory space is dynamically allocated.
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static const uint64_t kWindowsShadowOffset64 = kDynamicShadowSentinel;
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static const size_t kMinStackMallocSize = 1 << 6; // 64B
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static const size_t kMaxStackMallocSize = 1 << 16; // 64K
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static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
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static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
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static const char *const kAsanModuleCtorName = "asan.module_ctor";
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static const char *const kAsanModuleDtorName = "asan.module_dtor";
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static const uint64_t kAsanCtorAndDtorPriority = 1;
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// On Emscripten, the system needs more than one priorities for constructors.
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static const uint64_t kAsanEmscriptenCtorAndDtorPriority = 50;
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static const char *const kAsanReportErrorTemplate = "__asan_report_";
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static const char *const kAsanRegisterGlobalsName = "__asan_register_globals";
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static const char *const kAsanUnregisterGlobalsName =
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"__asan_unregister_globals";
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static const char *const kAsanRegisterImageGlobalsName =
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"__asan_register_image_globals";
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static const char *const kAsanUnregisterImageGlobalsName =
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"__asan_unregister_image_globals";
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static const char *const kAsanRegisterElfGlobalsName =
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"__asan_register_elf_globals";
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static const char *const kAsanUnregisterElfGlobalsName =
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"__asan_unregister_elf_globals";
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static const char *const kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
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static const char *const kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
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static const char *const kAsanInitName = "__asan_init";
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static const char *const kAsanVersionCheckNamePrefix =
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"__asan_version_mismatch_check_v";
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static const char *const kAsanPtrCmp = "__sanitizer_ptr_cmp";
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static const char *const kAsanPtrSub = "__sanitizer_ptr_sub";
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static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return";
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static const int kMaxAsanStackMallocSizeClass = 10;
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static const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_";
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static const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_";
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static const char *const kAsanGenPrefix = "___asan_gen_";
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static const char *const kODRGenPrefix = "__odr_asan_gen_";
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static const char *const kSanCovGenPrefix = "__sancov_gen_";
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static const char *const kAsanSetShadowPrefix = "__asan_set_shadow_";
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static const char *const kAsanPoisonStackMemoryName =
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"__asan_poison_stack_memory";
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static const char *const kAsanUnpoisonStackMemoryName =
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"__asan_unpoison_stack_memory";
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// ASan version script has __asan_* wildcard. Triple underscore prevents a
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// linker (gold) warning about attempting to export a local symbol.
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static const char *const kAsanGlobalsRegisteredFlagName =
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"___asan_globals_registered";
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static const char *const kAsanOptionDetectUseAfterReturn =
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"__asan_option_detect_stack_use_after_return";
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static const char *const kAsanShadowMemoryDynamicAddress =
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"__asan_shadow_memory_dynamic_address";
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static const char *const kAsanAllocaPoison = "__asan_alloca_poison";
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static const char *const kAsanAllocasUnpoison = "__asan_allocas_unpoison";
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// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
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static const size_t kNumberOfAccessSizes = 5;
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static const unsigned kAllocaRzSize = 32;
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// Command-line flags.
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static cl::opt<bool> ClEnableKasan(
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"asan-kernel", cl::desc("Enable KernelAddressSanitizer instrumentation"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClRecover(
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"asan-recover",
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cl::desc("Enable recovery mode (continue-after-error)."),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClInsertVersionCheck(
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"asan-guard-against-version-mismatch",
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cl::desc("Guard against compiler/runtime version mismatch."),
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cl::Hidden, cl::init(true));
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// This flag may need to be replaced with -f[no-]asan-reads.
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static cl::opt<bool> ClInstrumentReads("asan-instrument-reads",
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cl::desc("instrument read instructions"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInstrumentWrites(
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"asan-instrument-writes", cl::desc("instrument write instructions"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInstrumentAtomics(
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"asan-instrument-atomics",
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cl::desc("instrument atomic instructions (rmw, cmpxchg)"), cl::Hidden,
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cl::init(true));
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static cl::opt<bool> ClAlwaysSlowPath(
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"asan-always-slow-path",
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cl::desc("use instrumentation with slow path for all accesses"), cl::Hidden,
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cl::init(false));
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static cl::opt<bool> ClForceDynamicShadow(
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"asan-force-dynamic-shadow",
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cl::desc("Load shadow address into a local variable for each function"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool>
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ClWithIfunc("asan-with-ifunc",
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cl::desc("Access dynamic shadow through an ifunc global on "
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"platforms that support this"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClWithIfuncSuppressRemat(
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"asan-with-ifunc-suppress-remat",
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cl::desc("Suppress rematerialization of dynamic shadow address by passing "
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"it through inline asm in prologue."),
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cl::Hidden, cl::init(true));
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// This flag limits the number of instructions to be instrumented
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// in any given BB. Normally, this should be set to unlimited (INT_MAX),
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// but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
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// set it to 10000.
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static cl::opt<int> ClMaxInsnsToInstrumentPerBB(
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"asan-max-ins-per-bb", cl::init(10000),
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cl::desc("maximal number of instructions to instrument in any given BB"),
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cl::Hidden);
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// This flag may need to be replaced with -f[no]asan-stack.
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static cl::opt<bool> ClStack("asan-stack", cl::desc("Handle stack memory"),
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cl::Hidden, cl::init(true));
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static cl::opt<uint32_t> ClMaxInlinePoisoningSize(
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"asan-max-inline-poisoning-size",
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cl::desc(
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"Inline shadow poisoning for blocks up to the given size in bytes."),
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cl::Hidden, cl::init(64));
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static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
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cl::desc("Check stack-use-after-return"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClRedzoneByvalArgs("asan-redzone-byval-args",
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cl::desc("Create redzones for byval "
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"arguments (extra copy "
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"required)"), cl::Hidden,
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cl::init(true));
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static cl::opt<bool> ClUseAfterScope("asan-use-after-scope",
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cl::desc("Check stack-use-after-scope"),
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cl::Hidden, cl::init(false));
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// This flag may need to be replaced with -f[no]asan-globals.
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static cl::opt<bool> ClGlobals("asan-globals",
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cl::desc("Handle global objects"), cl::Hidden,
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cl::init(true));
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static cl::opt<bool> ClInitializers("asan-initialization-order",
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cl::desc("Handle C++ initializer order"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInvalidPointerPairs(
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"asan-detect-invalid-pointer-pair",
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cl::desc("Instrument <, <=, >, >=, - with pointer operands"), cl::Hidden,
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cl::init(false));
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static cl::opt<bool> ClInvalidPointerCmp(
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"asan-detect-invalid-pointer-cmp",
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cl::desc("Instrument <, <=, >, >= with pointer operands"), cl::Hidden,
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cl::init(false));
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static cl::opt<bool> ClInvalidPointerSub(
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"asan-detect-invalid-pointer-sub",
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cl::desc("Instrument - operations with pointer operands"), cl::Hidden,
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cl::init(false));
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static cl::opt<unsigned> ClRealignStack(
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"asan-realign-stack",
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cl::desc("Realign stack to the value of this flag (power of two)"),
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cl::Hidden, cl::init(32));
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static cl::opt<int> ClInstrumentationWithCallsThreshold(
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"asan-instrumentation-with-call-threshold",
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cl::desc(
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"If the function being instrumented contains more than "
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"this number of memory accesses, use callbacks instead of "
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"inline checks (-1 means never use callbacks)."),
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cl::Hidden, cl::init(7000));
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static cl::opt<std::string> ClMemoryAccessCallbackPrefix(
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"asan-memory-access-callback-prefix",
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cl::desc("Prefix for memory access callbacks"), cl::Hidden,
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cl::init("__asan_"));
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static cl::opt<bool>
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ClInstrumentDynamicAllocas("asan-instrument-dynamic-allocas",
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cl::desc("instrument dynamic allocas"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClSkipPromotableAllocas(
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"asan-skip-promotable-allocas",
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cl::desc("Do not instrument promotable allocas"), cl::Hidden,
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cl::init(true));
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// These flags allow to change the shadow mapping.
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// The shadow mapping looks like
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// Shadow = (Mem >> scale) + offset
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static cl::opt<int> ClMappingScale("asan-mapping-scale",
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cl::desc("scale of asan shadow mapping"),
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cl::Hidden, cl::init(0));
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static cl::opt<uint64_t>
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ClMappingOffset("asan-mapping-offset",
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cl::desc("offset of asan shadow mapping [EXPERIMENTAL]"),
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cl::Hidden, cl::init(0));
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// Optimization flags. Not user visible, used mostly for testing
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// and benchmarking the tool.
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static cl::opt<bool> ClOpt("asan-opt", cl::desc("Optimize instrumentation"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClOptSameTemp(
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"asan-opt-same-temp", cl::desc("Instrument the same temp just once"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClOptGlobals("asan-opt-globals",
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cl::desc("Don't instrument scalar globals"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClOptStack(
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"asan-opt-stack", cl::desc("Don't instrument scalar stack variables"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClDynamicAllocaStack(
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"asan-stack-dynamic-alloca",
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cl::desc("Use dynamic alloca to represent stack variables"), cl::Hidden,
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cl::init(true));
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static cl::opt<uint32_t> ClForceExperiment(
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"asan-force-experiment",
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cl::desc("Force optimization experiment (for testing)"), cl::Hidden,
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cl::init(0));
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static cl::opt<bool>
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ClUsePrivateAlias("asan-use-private-alias",
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cl::desc("Use private aliases for global variables"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool>
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ClUseOdrIndicator("asan-use-odr-indicator",
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cl::desc("Use odr indicators to improve ODR reporting"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool>
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ClUseGlobalsGC("asan-globals-live-support",
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cl::desc("Use linker features to support dead "
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"code stripping of globals"),
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cl::Hidden, cl::init(true));
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|
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// This is on by default even though there is a bug in gold:
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// https://sourceware.org/bugzilla/show_bug.cgi?id=19002
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static cl::opt<bool>
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ClWithComdat("asan-with-comdat",
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cl::desc("Place ASan constructors in comdat sections"),
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cl::Hidden, cl::init(true));
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// Debug flags.
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static cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden,
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cl::init(0));
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static cl::opt<int> ClDebugStack("asan-debug-stack", cl::desc("debug stack"),
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cl::Hidden, cl::init(0));
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static cl::opt<std::string> ClDebugFunc("asan-debug-func", cl::Hidden,
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cl::desc("Debug func"));
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static cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"),
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cl::Hidden, cl::init(-1));
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static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug max inst"),
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cl::Hidden, cl::init(-1));
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STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
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STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
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STATISTIC(NumOptimizedAccessesToGlobalVar,
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"Number of optimized accesses to global vars");
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STATISTIC(NumOptimizedAccessesToStackVar,
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"Number of optimized accesses to stack vars");
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namespace {
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/// This struct defines the shadow mapping using the rule:
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/// shadow = (mem >> Scale) ADD-or-OR Offset.
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/// If InGlobal is true, then
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/// extern char __asan_shadow[];
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/// shadow = (mem >> Scale) + &__asan_shadow
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struct ShadowMapping {
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int Scale;
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uint64_t Offset;
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bool OrShadowOffset;
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bool InGlobal;
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};
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} // end anonymous namespace
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static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
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bool IsKasan) {
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bool IsAndroid = TargetTriple.isAndroid();
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bool IsIOS = TargetTriple.isiOS() || TargetTriple.isWatchOS();
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bool IsFreeBSD = TargetTriple.isOSFreeBSD();
|
|
bool IsNetBSD = TargetTriple.isOSNetBSD();
|
|
bool IsPS4CPU = TargetTriple.isPS4CPU();
|
|
bool IsLinux = TargetTriple.isOSLinux();
|
|
bool IsPPC64 = TargetTriple.getArch() == Triple::ppc64 ||
|
|
TargetTriple.getArch() == Triple::ppc64le;
|
|
bool IsSystemZ = TargetTriple.getArch() == Triple::systemz;
|
|
bool IsX86_64 = TargetTriple.getArch() == Triple::x86_64;
|
|
bool IsMIPS32 = TargetTriple.isMIPS32();
|
|
bool IsMIPS64 = TargetTriple.isMIPS64();
|
|
bool IsArmOrThumb = TargetTriple.isARM() || TargetTriple.isThumb();
|
|
bool IsAArch64 = TargetTriple.getArch() == Triple::aarch64;
|
|
bool IsWindows = TargetTriple.isOSWindows();
|
|
bool IsFuchsia = TargetTriple.isOSFuchsia();
|
|
bool IsMyriad = TargetTriple.getVendor() == llvm::Triple::Myriad;
|
|
bool IsEmscripten = TargetTriple.isOSEmscripten();
|
|
|
|
ShadowMapping Mapping;
|
|
|
|
Mapping.Scale = IsMyriad ? kMyriadShadowScale : kDefaultShadowScale;
|
|
if (ClMappingScale.getNumOccurrences() > 0) {
|
|
Mapping.Scale = ClMappingScale;
|
|
}
|
|
|
|
if (LongSize == 32) {
|
|
if (IsAndroid)
|
|
Mapping.Offset = kDynamicShadowSentinel;
|
|
else if (IsMIPS32)
|
|
Mapping.Offset = kMIPS32_ShadowOffset32;
|
|
else if (IsFreeBSD)
|
|
Mapping.Offset = kFreeBSD_ShadowOffset32;
|
|
else if (IsNetBSD)
|
|
Mapping.Offset = kNetBSD_ShadowOffset32;
|
|
else if (IsIOS)
|
|
Mapping.Offset = kDynamicShadowSentinel;
|
|
else if (IsWindows)
|
|
Mapping.Offset = kWindowsShadowOffset32;
|
|
else if (IsEmscripten)
|
|
Mapping.Offset = kEmscriptenShadowOffset;
|
|
else if (IsMyriad) {
|
|
uint64_t ShadowOffset = (kMyriadMemoryOffset32 + kMyriadMemorySize32 -
|
|
(kMyriadMemorySize32 >> Mapping.Scale));
|
|
Mapping.Offset = ShadowOffset - (kMyriadMemoryOffset32 >> Mapping.Scale);
|
|
}
|
|
else
|
|
Mapping.Offset = kDefaultShadowOffset32;
|
|
} else { // LongSize == 64
|
|
// Fuchsia is always PIE, which means that the beginning of the address
|
|
// space is always available.
|
|
if (IsFuchsia)
|
|
Mapping.Offset = 0;
|
|
else if (IsPPC64)
|
|
Mapping.Offset = kPPC64_ShadowOffset64;
|
|
else if (IsSystemZ)
|
|
Mapping.Offset = kSystemZ_ShadowOffset64;
|
|
else if (IsFreeBSD && !IsMIPS64)
|
|
Mapping.Offset = kFreeBSD_ShadowOffset64;
|
|
else if (IsNetBSD) {
|
|
if (IsKasan)
|
|
Mapping.Offset = kNetBSDKasan_ShadowOffset64;
|
|
else
|
|
Mapping.Offset = kNetBSD_ShadowOffset64;
|
|
} else if (IsPS4CPU)
|
|
Mapping.Offset = kPS4CPU_ShadowOffset64;
|
|
else if (IsLinux && IsX86_64) {
|
|
if (IsKasan)
|
|
Mapping.Offset = kLinuxKasan_ShadowOffset64;
|
|
else
|
|
Mapping.Offset = (kSmallX86_64ShadowOffsetBase &
|
|
(kSmallX86_64ShadowOffsetAlignMask << Mapping.Scale));
|
|
} else if (IsWindows && IsX86_64) {
|
|
Mapping.Offset = kWindowsShadowOffset64;
|
|
} else if (IsMIPS64)
|
|
Mapping.Offset = kMIPS64_ShadowOffset64;
|
|
else if (IsIOS)
|
|
Mapping.Offset = kDynamicShadowSentinel;
|
|
else if (IsAArch64)
|
|
Mapping.Offset = kAArch64_ShadowOffset64;
|
|
else
|
|
Mapping.Offset = kDefaultShadowOffset64;
|
|
}
|
|
|
|
if (ClForceDynamicShadow) {
|
|
Mapping.Offset = kDynamicShadowSentinel;
|
|
}
|
|
|
|
if (ClMappingOffset.getNumOccurrences() > 0) {
|
|
Mapping.Offset = ClMappingOffset;
|
|
}
|
|
|
|
// OR-ing shadow offset if more efficient (at least on x86) if the offset
|
|
// is a power of two, but on ppc64 we have to use add since the shadow
|
|
// offset is not necessary 1/8-th of the address space. On SystemZ,
|
|
// we could OR the constant in a single instruction, but it's more
|
|
// efficient to load it once and use indexed addressing.
|
|
Mapping.OrShadowOffset = !IsAArch64 && !IsPPC64 && !IsSystemZ && !IsPS4CPU &&
|
|
!(Mapping.Offset & (Mapping.Offset - 1)) &&
|
|
Mapping.Offset != kDynamicShadowSentinel;
|
|
bool IsAndroidWithIfuncSupport =
|
|
IsAndroid && !TargetTriple.isAndroidVersionLT(21);
|
|
Mapping.InGlobal = ClWithIfunc && IsAndroidWithIfuncSupport && IsArmOrThumb;
|
|
|
|
return Mapping;
|
|
}
|
|
|
|
static size_t RedzoneSizeForScale(int MappingScale) {
|
|
// Redzone used for stack and globals is at least 32 bytes.
|
|
// For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
|
|
return std::max(32U, 1U << MappingScale);
|
|
}
|
|
|
|
static uint64_t GetCtorAndDtorPriority(Triple &TargetTriple) {
|
|
if (TargetTriple.isOSEmscripten()) {
|
|
return kAsanEmscriptenCtorAndDtorPriority;
|
|
} else {
|
|
return kAsanCtorAndDtorPriority;
|
|
}
|
|
}
|
|
|
|
namespace {
|
|
|
|
/// Module analysis for getting various metadata about the module.
|
|
class ASanGlobalsMetadataWrapperPass : public ModulePass {
|
|
public:
|
|
static char ID;
|
|
|
|
ASanGlobalsMetadataWrapperPass() : ModulePass(ID) {
|
|
initializeASanGlobalsMetadataWrapperPassPass(
|
|
*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
bool runOnModule(Module &M) override {
|
|
GlobalsMD = GlobalsMetadata(M);
|
|
return false;
|
|
}
|
|
|
|
StringRef getPassName() const override {
|
|
return "ASanGlobalsMetadataWrapperPass";
|
|
}
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.setPreservesAll();
|
|
}
|
|
|
|
GlobalsMetadata &getGlobalsMD() { return GlobalsMD; }
|
|
|
|
private:
|
|
GlobalsMetadata GlobalsMD;
|
|
};
|
|
|
|
char ASanGlobalsMetadataWrapperPass::ID = 0;
|
|
|
|
/// AddressSanitizer: instrument the code in module to find memory bugs.
|
|
struct AddressSanitizer {
|
|
AddressSanitizer(Module &M, const GlobalsMetadata *GlobalsMD,
|
|
bool CompileKernel = false, bool Recover = false,
|
|
bool UseAfterScope = false)
|
|
: UseAfterScope(UseAfterScope || ClUseAfterScope), GlobalsMD(*GlobalsMD) {
|
|
this->Recover = ClRecover.getNumOccurrences() > 0 ? ClRecover : Recover;
|
|
this->CompileKernel =
|
|
ClEnableKasan.getNumOccurrences() > 0 ? ClEnableKasan : CompileKernel;
|
|
|
|
C = &(M.getContext());
|
|
LongSize = M.getDataLayout().getPointerSizeInBits();
|
|
IntptrTy = Type::getIntNTy(*C, LongSize);
|
|
TargetTriple = Triple(M.getTargetTriple());
|
|
|
|
Mapping = getShadowMapping(TargetTriple, LongSize, this->CompileKernel);
|
|
}
|
|
|
|
uint64_t getAllocaSizeInBytes(const AllocaInst &AI) const {
|
|
uint64_t ArraySize = 1;
|
|
if (AI.isArrayAllocation()) {
|
|
const ConstantInt *CI = dyn_cast<ConstantInt>(AI.getArraySize());
|
|
assert(CI && "non-constant array size");
|
|
ArraySize = CI->getZExtValue();
|
|
}
|
|
Type *Ty = AI.getAllocatedType();
|
|
uint64_t SizeInBytes =
|
|
AI.getModule()->getDataLayout().getTypeAllocSize(Ty);
|
|
return SizeInBytes * ArraySize;
|
|
}
|
|
|
|
/// Check if we want (and can) handle this alloca.
|
|
bool isInterestingAlloca(const AllocaInst &AI);
|
|
|
|
/// If it is an interesting memory access, return the PointerOperand
|
|
/// and set IsWrite/Alignment. Otherwise return nullptr.
|
|
/// MaybeMask is an output parameter for the mask Value, if we're looking at a
|
|
/// masked load/store.
|
|
Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
|
|
uint64_t *TypeSize, unsigned *Alignment,
|
|
Value **MaybeMask = nullptr);
|
|
|
|
void instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis, Instruction *I,
|
|
bool UseCalls, const DataLayout &DL);
|
|
void instrumentPointerComparisonOrSubtraction(Instruction *I);
|
|
void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
|
|
Value *Addr, uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls, uint32_t Exp);
|
|
void instrumentUnusualSizeOrAlignment(Instruction *I,
|
|
Instruction *InsertBefore, Value *Addr,
|
|
uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls,
|
|
uint32_t Exp);
|
|
Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
|
|
Value *ShadowValue, uint32_t TypeSize);
|
|
Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
|
|
bool IsWrite, size_t AccessSizeIndex,
|
|
Value *SizeArgument, uint32_t Exp);
|
|
void instrumentMemIntrinsic(MemIntrinsic *MI);
|
|
Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
|
|
bool instrumentFunction(Function &F, const TargetLibraryInfo *TLI);
|
|
bool maybeInsertAsanInitAtFunctionEntry(Function &F);
|
|
void maybeInsertDynamicShadowAtFunctionEntry(Function &F);
|
|
void markEscapedLocalAllocas(Function &F);
|
|
|
|
private:
|
|
friend struct FunctionStackPoisoner;
|
|
|
|
void initializeCallbacks(Module &M);
|
|
|
|
bool LooksLikeCodeInBug11395(Instruction *I);
|
|
bool GlobalIsLinkerInitialized(GlobalVariable *G);
|
|
bool isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis, Value *Addr,
|
|
uint64_t TypeSize) const;
|
|
|
|
/// Helper to cleanup per-function state.
|
|
struct FunctionStateRAII {
|
|
AddressSanitizer *Pass;
|
|
|
|
FunctionStateRAII(AddressSanitizer *Pass) : Pass(Pass) {
|
|
assert(Pass->ProcessedAllocas.empty() &&
|
|
"last pass forgot to clear cache");
|
|
assert(!Pass->LocalDynamicShadow);
|
|
}
|
|
|
|
~FunctionStateRAII() {
|
|
Pass->LocalDynamicShadow = nullptr;
|
|
Pass->ProcessedAllocas.clear();
|
|
}
|
|
};
|
|
|
|
LLVMContext *C;
|
|
Triple TargetTriple;
|
|
int LongSize;
|
|
bool CompileKernel;
|
|
bool Recover;
|
|
bool UseAfterScope;
|
|
Type *IntptrTy;
|
|
ShadowMapping Mapping;
|
|
FunctionCallee AsanHandleNoReturnFunc;
|
|
FunctionCallee AsanPtrCmpFunction, AsanPtrSubFunction;
|
|
Constant *AsanShadowGlobal;
|
|
|
|
// These arrays is indexed by AccessIsWrite, Experiment and log2(AccessSize).
|
|
FunctionCallee AsanErrorCallback[2][2][kNumberOfAccessSizes];
|
|
FunctionCallee AsanMemoryAccessCallback[2][2][kNumberOfAccessSizes];
|
|
|
|
// These arrays is indexed by AccessIsWrite and Experiment.
|
|
FunctionCallee AsanErrorCallbackSized[2][2];
|
|
FunctionCallee AsanMemoryAccessCallbackSized[2][2];
|
|
|
|
FunctionCallee AsanMemmove, AsanMemcpy, AsanMemset;
|
|
InlineAsm *EmptyAsm;
|
|
Value *LocalDynamicShadow = nullptr;
|
|
const GlobalsMetadata &GlobalsMD;
|
|
DenseMap<const AllocaInst *, bool> ProcessedAllocas;
|
|
};
|
|
|
|
class AddressSanitizerLegacyPass : public FunctionPass {
|
|
public:
|
|
static char ID;
|
|
|
|
explicit AddressSanitizerLegacyPass(bool CompileKernel = false,
|
|
bool Recover = false,
|
|
bool UseAfterScope = false)
|
|
: FunctionPass(ID), CompileKernel(CompileKernel), Recover(Recover),
|
|
UseAfterScope(UseAfterScope) {
|
|
initializeAddressSanitizerLegacyPassPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
StringRef getPassName() const override {
|
|
return "AddressSanitizerFunctionPass";
|
|
}
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.addRequired<ASanGlobalsMetadataWrapperPass>();
|
|
AU.addRequired<TargetLibraryInfoWrapperPass>();
|
|
}
|
|
|
|
bool runOnFunction(Function &F) override {
|
|
GlobalsMetadata &GlobalsMD =
|
|
getAnalysis<ASanGlobalsMetadataWrapperPass>().getGlobalsMD();
|
|
const TargetLibraryInfo *TLI =
|
|
&getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
|
|
AddressSanitizer ASan(*F.getParent(), &GlobalsMD, CompileKernel, Recover,
|
|
UseAfterScope);
|
|
return ASan.instrumentFunction(F, TLI);
|
|
}
|
|
|
|
private:
|
|
bool CompileKernel;
|
|
bool Recover;
|
|
bool UseAfterScope;
|
|
};
|
|
|
|
class ModuleAddressSanitizer {
|
|
public:
|
|
ModuleAddressSanitizer(Module &M, const GlobalsMetadata *GlobalsMD,
|
|
bool CompileKernel = false, bool Recover = false,
|
|
bool UseGlobalsGC = true, bool UseOdrIndicator = false)
|
|
: GlobalsMD(*GlobalsMD), UseGlobalsGC(UseGlobalsGC && ClUseGlobalsGC),
|
|
// Enable aliases as they should have no downside with ODR indicators.
|
|
UsePrivateAlias(UseOdrIndicator || ClUsePrivateAlias),
|
|
UseOdrIndicator(UseOdrIndicator || ClUseOdrIndicator),
|
|
// Not a typo: ClWithComdat is almost completely pointless without
|
|
// ClUseGlobalsGC (because then it only works on modules without
|
|
// globals, which are rare); it is a prerequisite for ClUseGlobalsGC;
|
|
// and both suffer from gold PR19002 for which UseGlobalsGC constructor
|
|
// argument is designed as workaround. Therefore, disable both
|
|
// ClWithComdat and ClUseGlobalsGC unless the frontend says it's ok to
|
|
// do globals-gc.
|
|
UseCtorComdat(UseGlobalsGC && ClWithComdat) {
|
|
this->Recover = ClRecover.getNumOccurrences() > 0 ? ClRecover : Recover;
|
|
this->CompileKernel =
|
|
ClEnableKasan.getNumOccurrences() > 0 ? ClEnableKasan : CompileKernel;
|
|
|
|
C = &(M.getContext());
|
|
int LongSize = M.getDataLayout().getPointerSizeInBits();
|
|
IntptrTy = Type::getIntNTy(*C, LongSize);
|
|
TargetTriple = Triple(M.getTargetTriple());
|
|
Mapping = getShadowMapping(TargetTriple, LongSize, this->CompileKernel);
|
|
}
|
|
|
|
bool instrumentModule(Module &);
|
|
|
|
private:
|
|
void initializeCallbacks(Module &M);
|
|
|
|
bool InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool *CtorComdat);
|
|
void InstrumentGlobalsCOFF(IRBuilder<> &IRB, Module &M,
|
|
ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers);
|
|
void InstrumentGlobalsELF(IRBuilder<> &IRB, Module &M,
|
|
ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers,
|
|
const std::string &UniqueModuleId);
|
|
void InstrumentGlobalsMachO(IRBuilder<> &IRB, Module &M,
|
|
ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers);
|
|
void
|
|
InstrumentGlobalsWithMetadataArray(IRBuilder<> &IRB, Module &M,
|
|
ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers);
|
|
|
|
GlobalVariable *CreateMetadataGlobal(Module &M, Constant *Initializer,
|
|
StringRef OriginalName);
|
|
void SetComdatForGlobalMetadata(GlobalVariable *G, GlobalVariable *Metadata,
|
|
StringRef InternalSuffix);
|
|
IRBuilder<> CreateAsanModuleDtor(Module &M);
|
|
|
|
bool ShouldInstrumentGlobal(GlobalVariable *G);
|
|
bool ShouldUseMachOGlobalsSection() const;
|
|
StringRef getGlobalMetadataSection() const;
|
|
void poisonOneInitializer(Function &GlobalInit, GlobalValue *ModuleName);
|
|
void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName);
|
|
size_t MinRedzoneSizeForGlobal() const {
|
|
return RedzoneSizeForScale(Mapping.Scale);
|
|
}
|
|
int GetAsanVersion(const Module &M) const;
|
|
|
|
const GlobalsMetadata &GlobalsMD;
|
|
bool CompileKernel;
|
|
bool Recover;
|
|
bool UseGlobalsGC;
|
|
bool UsePrivateAlias;
|
|
bool UseOdrIndicator;
|
|
bool UseCtorComdat;
|
|
Type *IntptrTy;
|
|
LLVMContext *C;
|
|
Triple TargetTriple;
|
|
ShadowMapping Mapping;
|
|
FunctionCallee AsanPoisonGlobals;
|
|
FunctionCallee AsanUnpoisonGlobals;
|
|
FunctionCallee AsanRegisterGlobals;
|
|
FunctionCallee AsanUnregisterGlobals;
|
|
FunctionCallee AsanRegisterImageGlobals;
|
|
FunctionCallee AsanUnregisterImageGlobals;
|
|
FunctionCallee AsanRegisterElfGlobals;
|
|
FunctionCallee AsanUnregisterElfGlobals;
|
|
|
|
Function *AsanCtorFunction = nullptr;
|
|
Function *AsanDtorFunction = nullptr;
|
|
};
|
|
|
|
class ModuleAddressSanitizerLegacyPass : public ModulePass {
|
|
public:
|
|
static char ID;
|
|
|
|
explicit ModuleAddressSanitizerLegacyPass(bool CompileKernel = false,
|
|
bool Recover = false,
|
|
bool UseGlobalGC = true,
|
|
bool UseOdrIndicator = false)
|
|
: ModulePass(ID), CompileKernel(CompileKernel), Recover(Recover),
|
|
UseGlobalGC(UseGlobalGC), UseOdrIndicator(UseOdrIndicator) {
|
|
initializeModuleAddressSanitizerLegacyPassPass(
|
|
*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
StringRef getPassName() const override { return "ModuleAddressSanitizer"; }
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.addRequired<ASanGlobalsMetadataWrapperPass>();
|
|
}
|
|
|
|
bool runOnModule(Module &M) override {
|
|
GlobalsMetadata &GlobalsMD =
|
|
getAnalysis<ASanGlobalsMetadataWrapperPass>().getGlobalsMD();
|
|
ModuleAddressSanitizer ASanModule(M, &GlobalsMD, CompileKernel, Recover,
|
|
UseGlobalGC, UseOdrIndicator);
|
|
return ASanModule.instrumentModule(M);
|
|
}
|
|
|
|
private:
|
|
bool CompileKernel;
|
|
bool Recover;
|
|
bool UseGlobalGC;
|
|
bool UseOdrIndicator;
|
|
};
|
|
|
|
// Stack poisoning does not play well with exception handling.
|
|
// When an exception is thrown, we essentially bypass the code
|
|
// that unpoisones the stack. This is why the run-time library has
|
|
// to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
|
|
// stack in the interceptor. This however does not work inside the
|
|
// actual function which catches the exception. Most likely because the
|
|
// compiler hoists the load of the shadow value somewhere too high.
|
|
// This causes asan to report a non-existing bug on 453.povray.
|
|
// It sounds like an LLVM bug.
|
|
struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
|
|
Function &F;
|
|
AddressSanitizer &ASan;
|
|
DIBuilder DIB;
|
|
LLVMContext *C;
|
|
Type *IntptrTy;
|
|
Type *IntptrPtrTy;
|
|
ShadowMapping Mapping;
|
|
|
|
SmallVector<AllocaInst *, 16> AllocaVec;
|
|
SmallVector<AllocaInst *, 16> StaticAllocasToMoveUp;
|
|
SmallVector<Instruction *, 8> RetVec;
|
|
unsigned StackAlignment;
|
|
|
|
FunctionCallee AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1],
|
|
AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
|
|
FunctionCallee AsanSetShadowFunc[0x100] = {};
|
|
FunctionCallee AsanPoisonStackMemoryFunc, AsanUnpoisonStackMemoryFunc;
|
|
FunctionCallee AsanAllocaPoisonFunc, AsanAllocasUnpoisonFunc;
|
|
|
|
// Stores a place and arguments of poisoning/unpoisoning call for alloca.
|
|
struct AllocaPoisonCall {
|
|
IntrinsicInst *InsBefore;
|
|
AllocaInst *AI;
|
|
uint64_t Size;
|
|
bool DoPoison;
|
|
};
|
|
SmallVector<AllocaPoisonCall, 8> DynamicAllocaPoisonCallVec;
|
|
SmallVector<AllocaPoisonCall, 8> StaticAllocaPoisonCallVec;
|
|
bool HasUntracedLifetimeIntrinsic = false;
|
|
|
|
SmallVector<AllocaInst *, 1> DynamicAllocaVec;
|
|
SmallVector<IntrinsicInst *, 1> StackRestoreVec;
|
|
AllocaInst *DynamicAllocaLayout = nullptr;
|
|
IntrinsicInst *LocalEscapeCall = nullptr;
|
|
|
|
// Maps Value to an AllocaInst from which the Value is originated.
|
|
using AllocaForValueMapTy = DenseMap<Value *, AllocaInst *>;
|
|
AllocaForValueMapTy AllocaForValue;
|
|
|
|
bool HasNonEmptyInlineAsm = false;
|
|
bool HasReturnsTwiceCall = false;
|
|
std::unique_ptr<CallInst> EmptyInlineAsm;
|
|
|
|
FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
|
|
: F(F), ASan(ASan), DIB(*F.getParent(), /*AllowUnresolved*/ false),
|
|
C(ASan.C), IntptrTy(ASan.IntptrTy),
|
|
IntptrPtrTy(PointerType::get(IntptrTy, 0)), Mapping(ASan.Mapping),
|
|
StackAlignment(1 << Mapping.Scale),
|
|
EmptyInlineAsm(CallInst::Create(ASan.EmptyAsm)) {}
|
|
|
|
bool runOnFunction() {
|
|
if (!ClStack) return false;
|
|
|
|
if (ClRedzoneByvalArgs)
|
|
copyArgsPassedByValToAllocas();
|
|
|
|
// Collect alloca, ret, lifetime instructions etc.
|
|
for (BasicBlock *BB : depth_first(&F.getEntryBlock())) visit(*BB);
|
|
|
|
if (AllocaVec.empty() && DynamicAllocaVec.empty()) return false;
|
|
|
|
initializeCallbacks(*F.getParent());
|
|
|
|
if (HasUntracedLifetimeIntrinsic) {
|
|
// If there are lifetime intrinsics which couldn't be traced back to an
|
|
// alloca, we may not know exactly when a variable enters scope, and
|
|
// therefore should "fail safe" by not poisoning them.
|
|
StaticAllocaPoisonCallVec.clear();
|
|
DynamicAllocaPoisonCallVec.clear();
|
|
}
|
|
|
|
processDynamicAllocas();
|
|
processStaticAllocas();
|
|
|
|
if (ClDebugStack) {
|
|
LLVM_DEBUG(dbgs() << F);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// Arguments marked with the "byval" attribute are implicitly copied without
|
|
// using an alloca instruction. To produce redzones for those arguments, we
|
|
// copy them a second time into memory allocated with an alloca instruction.
|
|
void copyArgsPassedByValToAllocas();
|
|
|
|
// Finds all Alloca instructions and puts
|
|
// poisoned red zones around all of them.
|
|
// Then unpoison everything back before the function returns.
|
|
void processStaticAllocas();
|
|
void processDynamicAllocas();
|
|
|
|
void createDynamicAllocasInitStorage();
|
|
|
|
// ----------------------- Visitors.
|
|
/// Collect all Ret instructions.
|
|
void visitReturnInst(ReturnInst &RI) { RetVec.push_back(&RI); }
|
|
|
|
/// Collect all Resume instructions.
|
|
void visitResumeInst(ResumeInst &RI) { RetVec.push_back(&RI); }
|
|
|
|
/// Collect all CatchReturnInst instructions.
|
|
void visitCleanupReturnInst(CleanupReturnInst &CRI) { RetVec.push_back(&CRI); }
|
|
|
|
void unpoisonDynamicAllocasBeforeInst(Instruction *InstBefore,
|
|
Value *SavedStack) {
|
|
IRBuilder<> IRB(InstBefore);
|
|
Value *DynamicAreaPtr = IRB.CreatePtrToInt(SavedStack, IntptrTy);
|
|
// When we insert _asan_allocas_unpoison before @llvm.stackrestore, we
|
|
// need to adjust extracted SP to compute the address of the most recent
|
|
// alloca. We have a special @llvm.get.dynamic.area.offset intrinsic for
|
|
// this purpose.
|
|
if (!isa<ReturnInst>(InstBefore)) {
|
|
Function *DynamicAreaOffsetFunc = Intrinsic::getDeclaration(
|
|
InstBefore->getModule(), Intrinsic::get_dynamic_area_offset,
|
|
{IntptrTy});
|
|
|
|
Value *DynamicAreaOffset = IRB.CreateCall(DynamicAreaOffsetFunc, {});
|
|
|
|
DynamicAreaPtr = IRB.CreateAdd(IRB.CreatePtrToInt(SavedStack, IntptrTy),
|
|
DynamicAreaOffset);
|
|
}
|
|
|
|
IRB.CreateCall(
|
|
AsanAllocasUnpoisonFunc,
|
|
{IRB.CreateLoad(IntptrTy, DynamicAllocaLayout), DynamicAreaPtr});
|
|
}
|
|
|
|
// Unpoison dynamic allocas redzones.
|
|
void unpoisonDynamicAllocas() {
|
|
for (auto &Ret : RetVec)
|
|
unpoisonDynamicAllocasBeforeInst(Ret, DynamicAllocaLayout);
|
|
|
|
for (auto &StackRestoreInst : StackRestoreVec)
|
|
unpoisonDynamicAllocasBeforeInst(StackRestoreInst,
|
|
StackRestoreInst->getOperand(0));
|
|
}
|
|
|
|
// Deploy and poison redzones around dynamic alloca call. To do this, we
|
|
// should replace this call with another one with changed parameters and
|
|
// replace all its uses with new address, so
|
|
// addr = alloca type, old_size, align
|
|
// is replaced by
|
|
// new_size = (old_size + additional_size) * sizeof(type)
|
|
// tmp = alloca i8, new_size, max(align, 32)
|
|
// addr = tmp + 32 (first 32 bytes are for the left redzone).
|
|
// Additional_size is added to make new memory allocation contain not only
|
|
// requested memory, but also left, partial and right redzones.
|
|
void handleDynamicAllocaCall(AllocaInst *AI);
|
|
|
|
/// Collect Alloca instructions we want (and can) handle.
|
|
void visitAllocaInst(AllocaInst &AI) {
|
|
if (!ASan.isInterestingAlloca(AI)) {
|
|
if (AI.isStaticAlloca()) {
|
|
// Skip over allocas that are present *before* the first instrumented
|
|
// alloca, we don't want to move those around.
|
|
if (AllocaVec.empty())
|
|
return;
|
|
|
|
StaticAllocasToMoveUp.push_back(&AI);
|
|
}
|
|
return;
|
|
}
|
|
|
|
StackAlignment = std::max(StackAlignment, AI.getAlignment());
|
|
if (!AI.isStaticAlloca())
|
|
DynamicAllocaVec.push_back(&AI);
|
|
else
|
|
AllocaVec.push_back(&AI);
|
|
}
|
|
|
|
/// Collect lifetime intrinsic calls to check for use-after-scope
|
|
/// errors.
|
|
void visitIntrinsicInst(IntrinsicInst &II) {
|
|
Intrinsic::ID ID = II.getIntrinsicID();
|
|
if (ID == Intrinsic::stackrestore) StackRestoreVec.push_back(&II);
|
|
if (ID == Intrinsic::localescape) LocalEscapeCall = &II;
|
|
if (!ASan.UseAfterScope)
|
|
return;
|
|
if (!II.isLifetimeStartOrEnd())
|
|
return;
|
|
// Found lifetime intrinsic, add ASan instrumentation if necessary.
|
|
auto *Size = cast<ConstantInt>(II.getArgOperand(0));
|
|
// If size argument is undefined, don't do anything.
|
|
if (Size->isMinusOne()) return;
|
|
// Check that size doesn't saturate uint64_t and can
|
|
// be stored in IntptrTy.
|
|
const uint64_t SizeValue = Size->getValue().getLimitedValue();
|
|
if (SizeValue == ~0ULL ||
|
|
!ConstantInt::isValueValidForType(IntptrTy, SizeValue))
|
|
return;
|
|
// Find alloca instruction that corresponds to llvm.lifetime argument.
|
|
AllocaInst *AI =
|
|
llvm::findAllocaForValue(II.getArgOperand(1), AllocaForValue);
|
|
if (!AI) {
|
|
HasUntracedLifetimeIntrinsic = true;
|
|
return;
|
|
}
|
|
// We're interested only in allocas we can handle.
|
|
if (!ASan.isInterestingAlloca(*AI))
|
|
return;
|
|
bool DoPoison = (ID == Intrinsic::lifetime_end);
|
|
AllocaPoisonCall APC = {&II, AI, SizeValue, DoPoison};
|
|
if (AI->isStaticAlloca())
|
|
StaticAllocaPoisonCallVec.push_back(APC);
|
|
else if (ClInstrumentDynamicAllocas)
|
|
DynamicAllocaPoisonCallVec.push_back(APC);
|
|
}
|
|
|
|
void visitCallSite(CallSite CS) {
|
|
Instruction *I = CS.getInstruction();
|
|
if (CallInst *CI = dyn_cast<CallInst>(I)) {
|
|
HasNonEmptyInlineAsm |= CI->isInlineAsm() &&
|
|
!CI->isIdenticalTo(EmptyInlineAsm.get()) &&
|
|
I != ASan.LocalDynamicShadow;
|
|
HasReturnsTwiceCall |= CI->canReturnTwice();
|
|
}
|
|
}
|
|
|
|
// ---------------------- Helpers.
|
|
void initializeCallbacks(Module &M);
|
|
|
|
// Copies bytes from ShadowBytes into shadow memory for indexes where
|
|
// ShadowMask is not zero. If ShadowMask[i] is zero, we assume that
|
|
// ShadowBytes[i] is constantly zero and doesn't need to be overwritten.
|
|
void copyToShadow(ArrayRef<uint8_t> ShadowMask, ArrayRef<uint8_t> ShadowBytes,
|
|
IRBuilder<> &IRB, Value *ShadowBase);
|
|
void copyToShadow(ArrayRef<uint8_t> ShadowMask, ArrayRef<uint8_t> ShadowBytes,
|
|
size_t Begin, size_t End, IRBuilder<> &IRB,
|
|
Value *ShadowBase);
|
|
void copyToShadowInline(ArrayRef<uint8_t> ShadowMask,
|
|
ArrayRef<uint8_t> ShadowBytes, size_t Begin,
|
|
size_t End, IRBuilder<> &IRB, Value *ShadowBase);
|
|
|
|
void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> &IRB, bool DoPoison);
|
|
|
|
Value *createAllocaForLayout(IRBuilder<> &IRB, const ASanStackFrameLayout &L,
|
|
bool Dynamic);
|
|
PHINode *createPHI(IRBuilder<> &IRB, Value *Cond, Value *ValueIfTrue,
|
|
Instruction *ThenTerm, Value *ValueIfFalse);
|
|
};
|
|
|
|
} // end anonymous namespace
|
|
|
|
void LocationMetadata::parse(MDNode *MDN) {
|
|
assert(MDN->getNumOperands() == 3);
|
|
MDString *DIFilename = cast<MDString>(MDN->getOperand(0));
|
|
Filename = DIFilename->getString();
|
|
LineNo = mdconst::extract<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
|
|
ColumnNo =
|
|
mdconst::extract<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
|
|
}
|
|
|
|
// FIXME: It would be cleaner to instead attach relevant metadata to the globals
|
|
// we want to sanitize instead and reading this metadata on each pass over a
|
|
// function instead of reading module level metadata at first.
|
|
GlobalsMetadata::GlobalsMetadata(Module &M) {
|
|
NamedMDNode *Globals = M.getNamedMetadata("llvm.asan.globals");
|
|
if (!Globals)
|
|
return;
|
|
for (auto MDN : Globals->operands()) {
|
|
// Metadata node contains the global and the fields of "Entry".
|
|
assert(MDN->getNumOperands() == 5);
|
|
auto *V = mdconst::extract_or_null<Constant>(MDN->getOperand(0));
|
|
// The optimizer may optimize away a global entirely.
|
|
if (!V)
|
|
continue;
|
|
auto *StrippedV = V->stripPointerCasts();
|
|
auto *GV = dyn_cast<GlobalVariable>(StrippedV);
|
|
if (!GV)
|
|
continue;
|
|
// We can already have an entry for GV if it was merged with another
|
|
// global.
|
|
Entry &E = Entries[GV];
|
|
if (auto *Loc = cast_or_null<MDNode>(MDN->getOperand(1)))
|
|
E.SourceLoc.parse(Loc);
|
|
if (auto *Name = cast_or_null<MDString>(MDN->getOperand(2)))
|
|
E.Name = Name->getString();
|
|
ConstantInt *IsDynInit = mdconst::extract<ConstantInt>(MDN->getOperand(3));
|
|
E.IsDynInit |= IsDynInit->isOne();
|
|
ConstantInt *IsBlacklisted =
|
|
mdconst::extract<ConstantInt>(MDN->getOperand(4));
|
|
E.IsBlacklisted |= IsBlacklisted->isOne();
|
|
}
|
|
}
|
|
|
|
AnalysisKey ASanGlobalsMetadataAnalysis::Key;
|
|
|
|
GlobalsMetadata ASanGlobalsMetadataAnalysis::run(Module &M,
|
|
ModuleAnalysisManager &AM) {
|
|
return GlobalsMetadata(M);
|
|
}
|
|
|
|
AddressSanitizerPass::AddressSanitizerPass(bool CompileKernel, bool Recover,
|
|
bool UseAfterScope)
|
|
: CompileKernel(CompileKernel), Recover(Recover),
|
|
UseAfterScope(UseAfterScope) {}
|
|
|
|
PreservedAnalyses AddressSanitizerPass::run(Function &F,
|
|
AnalysisManager<Function> &AM) {
|
|
auto &MAMProxy = AM.getResult<ModuleAnalysisManagerFunctionProxy>(F);
|
|
auto &MAM = MAMProxy.getManager();
|
|
Module &M = *F.getParent();
|
|
if (auto *R = MAM.getCachedResult<ASanGlobalsMetadataAnalysis>(M)) {
|
|
const TargetLibraryInfo *TLI = &AM.getResult<TargetLibraryAnalysis>(F);
|
|
AddressSanitizer Sanitizer(M, R, CompileKernel, Recover, UseAfterScope);
|
|
if (Sanitizer.instrumentFunction(F, TLI))
|
|
return PreservedAnalyses::none();
|
|
return PreservedAnalyses::all();
|
|
}
|
|
|
|
report_fatal_error(
|
|
"The ASanGlobalsMetadataAnalysis is required to run before "
|
|
"AddressSanitizer can run");
|
|
return PreservedAnalyses::all();
|
|
}
|
|
|
|
ModuleAddressSanitizerPass::ModuleAddressSanitizerPass(bool CompileKernel,
|
|
bool Recover,
|
|
bool UseGlobalGC,
|
|
bool UseOdrIndicator)
|
|
: CompileKernel(CompileKernel), Recover(Recover), UseGlobalGC(UseGlobalGC),
|
|
UseOdrIndicator(UseOdrIndicator) {}
|
|
|
|
PreservedAnalyses ModuleAddressSanitizerPass::run(Module &M,
|
|
AnalysisManager<Module> &AM) {
|
|
GlobalsMetadata &GlobalsMD = AM.getResult<ASanGlobalsMetadataAnalysis>(M);
|
|
ModuleAddressSanitizer Sanitizer(M, &GlobalsMD, CompileKernel, Recover,
|
|
UseGlobalGC, UseOdrIndicator);
|
|
if (Sanitizer.instrumentModule(M))
|
|
return PreservedAnalyses::none();
|
|
return PreservedAnalyses::all();
|
|
}
|
|
|
|
INITIALIZE_PASS(ASanGlobalsMetadataWrapperPass, "asan-globals-md",
|
|
"Read metadata to mark which globals should be instrumented "
|
|
"when running ASan.",
|
|
false, true)
|
|
|
|
char AddressSanitizerLegacyPass::ID = 0;
|
|
|
|
INITIALIZE_PASS_BEGIN(
|
|
AddressSanitizerLegacyPass, "asan",
|
|
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
|
|
false)
|
|
INITIALIZE_PASS_DEPENDENCY(ASanGlobalsMetadataWrapperPass)
|
|
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
|
|
INITIALIZE_PASS_END(
|
|
AddressSanitizerLegacyPass, "asan",
|
|
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
|
|
false)
|
|
|
|
FunctionPass *llvm::createAddressSanitizerFunctionPass(bool CompileKernel,
|
|
bool Recover,
|
|
bool UseAfterScope) {
|
|
assert(!CompileKernel || Recover);
|
|
return new AddressSanitizerLegacyPass(CompileKernel, Recover, UseAfterScope);
|
|
}
|
|
|
|
char ModuleAddressSanitizerLegacyPass::ID = 0;
|
|
|
|
INITIALIZE_PASS(
|
|
ModuleAddressSanitizerLegacyPass, "asan-module",
|
|
"AddressSanitizer: detects use-after-free and out-of-bounds bugs."
|
|
"ModulePass",
|
|
false, false)
|
|
|
|
ModulePass *llvm::createModuleAddressSanitizerLegacyPassPass(
|
|
bool CompileKernel, bool Recover, bool UseGlobalsGC, bool UseOdrIndicator) {
|
|
assert(!CompileKernel || Recover);
|
|
return new ModuleAddressSanitizerLegacyPass(CompileKernel, Recover,
|
|
UseGlobalsGC, UseOdrIndicator);
|
|
}
|
|
|
|
static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
|
|
size_t Res = countTrailingZeros(TypeSize / 8);
|
|
assert(Res < kNumberOfAccessSizes);
|
|
return Res;
|
|
}
|
|
|
|
/// Create a global describing a source location.
|
|
static GlobalVariable *createPrivateGlobalForSourceLoc(Module &M,
|
|
LocationMetadata MD) {
|
|
Constant *LocData[] = {
|
|
createPrivateGlobalForString(M, MD.Filename, true, kAsanGenPrefix),
|
|
ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.LineNo),
|
|
ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.ColumnNo),
|
|
};
|
|
auto LocStruct = ConstantStruct::getAnon(LocData);
|
|
auto GV = new GlobalVariable(M, LocStruct->getType(), true,
|
|
GlobalValue::PrivateLinkage, LocStruct,
|
|
kAsanGenPrefix);
|
|
GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
|
|
return GV;
|
|
}
|
|
|
|
/// Check if \p G has been created by a trusted compiler pass.
|
|
static bool GlobalWasGeneratedByCompiler(GlobalVariable *G) {
|
|
// Do not instrument @llvm.global_ctors, @llvm.used, etc.
|
|
if (G->getName().startswith("llvm."))
|
|
return true;
|
|
|
|
// Do not instrument asan globals.
|
|
if (G->getName().startswith(kAsanGenPrefix) ||
|
|
G->getName().startswith(kSanCovGenPrefix) ||
|
|
G->getName().startswith(kODRGenPrefix))
|
|
return true;
|
|
|
|
// Do not instrument gcov counter arrays.
|
|
if (G->getName() == "__llvm_gcov_ctr")
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
|
|
// Shadow >> scale
|
|
Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
|
|
if (Mapping.Offset == 0) return Shadow;
|
|
// (Shadow >> scale) | offset
|
|
Value *ShadowBase;
|
|
if (LocalDynamicShadow)
|
|
ShadowBase = LocalDynamicShadow;
|
|
else
|
|
ShadowBase = ConstantInt::get(IntptrTy, Mapping.Offset);
|
|
if (Mapping.OrShadowOffset)
|
|
return IRB.CreateOr(Shadow, ShadowBase);
|
|
else
|
|
return IRB.CreateAdd(Shadow, ShadowBase);
|
|
}
|
|
|
|
// Instrument memset/memmove/memcpy
|
|
void AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
|
|
IRBuilder<> IRB(MI);
|
|
if (isa<MemTransferInst>(MI)) {
|
|
IRB.CreateCall(
|
|
isa<MemMoveInst>(MI) ? AsanMemmove : AsanMemcpy,
|
|
{IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
|
|
IRB.CreatePointerCast(MI->getOperand(1), IRB.getInt8PtrTy()),
|
|
IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)});
|
|
} else if (isa<MemSetInst>(MI)) {
|
|
IRB.CreateCall(
|
|
AsanMemset,
|
|
{IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
|
|
IRB.CreateIntCast(MI->getOperand(1), IRB.getInt32Ty(), false),
|
|
IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)});
|
|
}
|
|
MI->eraseFromParent();
|
|
}
|
|
|
|
/// Check if we want (and can) handle this alloca.
|
|
bool AddressSanitizer::isInterestingAlloca(const AllocaInst &AI) {
|
|
auto PreviouslySeenAllocaInfo = ProcessedAllocas.find(&AI);
|
|
|
|
if (PreviouslySeenAllocaInfo != ProcessedAllocas.end())
|
|
return PreviouslySeenAllocaInfo->getSecond();
|
|
|
|
bool IsInteresting =
|
|
(AI.getAllocatedType()->isSized() &&
|
|
// alloca() may be called with 0 size, ignore it.
|
|
((!AI.isStaticAlloca()) || getAllocaSizeInBytes(AI) > 0) &&
|
|
// We are only interested in allocas not promotable to registers.
|
|
// Promotable allocas are common under -O0.
|
|
(!ClSkipPromotableAllocas || !isAllocaPromotable(&AI)) &&
|
|
// inalloca allocas are not treated as static, and we don't want
|
|
// dynamic alloca instrumentation for them as well.
|
|
!AI.isUsedWithInAlloca() &&
|
|
// swifterror allocas are register promoted by ISel
|
|
!AI.isSwiftError());
|
|
|
|
ProcessedAllocas[&AI] = IsInteresting;
|
|
return IsInteresting;
|
|
}
|
|
|
|
Value *AddressSanitizer::isInterestingMemoryAccess(Instruction *I,
|
|
bool *IsWrite,
|
|
uint64_t *TypeSize,
|
|
unsigned *Alignment,
|
|
Value **MaybeMask) {
|
|
// Skip memory accesses inserted by another instrumentation.
|
|
if (I->hasMetadata("nosanitize")) return nullptr;
|
|
|
|
// Do not instrument the load fetching the dynamic shadow address.
|
|
if (LocalDynamicShadow == I)
|
|
return nullptr;
|
|
|
|
Value *PtrOperand = nullptr;
|
|
const DataLayout &DL = I->getModule()->getDataLayout();
|
|
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
|
|
if (!ClInstrumentReads) return nullptr;
|
|
*IsWrite = false;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(LI->getType());
|
|
*Alignment = LI->getAlignment();
|
|
PtrOperand = LI->getPointerOperand();
|
|
} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
|
|
if (!ClInstrumentWrites) return nullptr;
|
|
*IsWrite = true;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(SI->getValueOperand()->getType());
|
|
*Alignment = SI->getAlignment();
|
|
PtrOperand = SI->getPointerOperand();
|
|
} else if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
|
|
if (!ClInstrumentAtomics) return nullptr;
|
|
*IsWrite = true;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(RMW->getValOperand()->getType());
|
|
*Alignment = 0;
|
|
PtrOperand = RMW->getPointerOperand();
|
|
} else if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
|
|
if (!ClInstrumentAtomics) return nullptr;
|
|
*IsWrite = true;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(XCHG->getCompareOperand()->getType());
|
|
*Alignment = 0;
|
|
PtrOperand = XCHG->getPointerOperand();
|
|
} else if (auto CI = dyn_cast<CallInst>(I)) {
|
|
auto *F = dyn_cast<Function>(CI->getCalledValue());
|
|
if (F && (F->getName().startswith("llvm.masked.load.") ||
|
|
F->getName().startswith("llvm.masked.store."))) {
|
|
unsigned OpOffset = 0;
|
|
if (F->getName().startswith("llvm.masked.store.")) {
|
|
if (!ClInstrumentWrites)
|
|
return nullptr;
|
|
// Masked store has an initial operand for the value.
|
|
OpOffset = 1;
|
|
*IsWrite = true;
|
|
} else {
|
|
if (!ClInstrumentReads)
|
|
return nullptr;
|
|
*IsWrite = false;
|
|
}
|
|
|
|
auto BasePtr = CI->getOperand(0 + OpOffset);
|
|
auto Ty = cast<PointerType>(BasePtr->getType())->getElementType();
|
|
*TypeSize = DL.getTypeStoreSizeInBits(Ty);
|
|
if (auto AlignmentConstant =
|
|
dyn_cast<ConstantInt>(CI->getOperand(1 + OpOffset)))
|
|
*Alignment = (unsigned)AlignmentConstant->getZExtValue();
|
|
else
|
|
*Alignment = 1; // No alignment guarantees. We probably got Undef
|
|
if (MaybeMask)
|
|
*MaybeMask = CI->getOperand(2 + OpOffset);
|
|
PtrOperand = BasePtr;
|
|
}
|
|
}
|
|
|
|
if (PtrOperand) {
|
|
// Do not instrument acesses from different address spaces; we cannot deal
|
|
// with them.
|
|
Type *PtrTy = cast<PointerType>(PtrOperand->getType()->getScalarType());
|
|
if (PtrTy->getPointerAddressSpace() != 0)
|
|
return nullptr;
|
|
|
|
// Ignore swifterror addresses.
|
|
// swifterror memory addresses are mem2reg promoted by instruction
|
|
// selection. As such they cannot have regular uses like an instrumentation
|
|
// function and it makes no sense to track them as memory.
|
|
if (PtrOperand->isSwiftError())
|
|
return nullptr;
|
|
}
|
|
|
|
// Treat memory accesses to promotable allocas as non-interesting since they
|
|
// will not cause memory violations. This greatly speeds up the instrumented
|
|
// executable at -O0.
|
|
if (ClSkipPromotableAllocas)
|
|
if (auto AI = dyn_cast_or_null<AllocaInst>(PtrOperand))
|
|
return isInterestingAlloca(*AI) ? AI : nullptr;
|
|
|
|
return PtrOperand;
|
|
}
|
|
|
|
static bool isPointerOperand(Value *V) {
|
|
return V->getType()->isPointerTy() || isa<PtrToIntInst>(V);
|
|
}
|
|
|
|
// This is a rough heuristic; it may cause both false positives and
|
|
// false negatives. The proper implementation requires cooperation with
|
|
// the frontend.
|
|
static bool isInterestingPointerComparison(Instruction *I) {
|
|
if (ICmpInst *Cmp = dyn_cast<ICmpInst>(I)) {
|
|
if (!Cmp->isRelational())
|
|
return false;
|
|
} else {
|
|
return false;
|
|
}
|
|
return isPointerOperand(I->getOperand(0)) &&
|
|
isPointerOperand(I->getOperand(1));
|
|
}
|
|
|
|
// This is a rough heuristic; it may cause both false positives and
|
|
// false negatives. The proper implementation requires cooperation with
|
|
// the frontend.
|
|
static bool isInterestingPointerSubtraction(Instruction *I) {
|
|
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
|
|
if (BO->getOpcode() != Instruction::Sub)
|
|
return false;
|
|
} else {
|
|
return false;
|
|
}
|
|
return isPointerOperand(I->getOperand(0)) &&
|
|
isPointerOperand(I->getOperand(1));
|
|
}
|
|
|
|
bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) {
|
|
// If a global variable does not have dynamic initialization we don't
|
|
// have to instrument it. However, if a global does not have initializer
|
|
// at all, we assume it has dynamic initializer (in other TU).
|
|
//
|
|
// FIXME: Metadata should be attched directly to the global directly instead
|
|
// of being added to llvm.asan.globals.
|
|
return G->hasInitializer() && !GlobalsMD.get(G).IsDynInit;
|
|
}
|
|
|
|
void AddressSanitizer::instrumentPointerComparisonOrSubtraction(
|
|
Instruction *I) {
|
|
IRBuilder<> IRB(I);
|
|
FunctionCallee F = isa<ICmpInst>(I) ? AsanPtrCmpFunction : AsanPtrSubFunction;
|
|
Value *Param[2] = {I->getOperand(0), I->getOperand(1)};
|
|
for (Value *&i : Param) {
|
|
if (i->getType()->isPointerTy())
|
|
i = IRB.CreatePointerCast(i, IntptrTy);
|
|
}
|
|
IRB.CreateCall(F, Param);
|
|
}
|
|
|
|
static void doInstrumentAddress(AddressSanitizer *Pass, Instruction *I,
|
|
Instruction *InsertBefore, Value *Addr,
|
|
unsigned Alignment, unsigned Granularity,
|
|
uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls,
|
|
uint32_t Exp) {
|
|
// Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check
|
|
// if the data is properly aligned.
|
|
if ((TypeSize == 8 || TypeSize == 16 || TypeSize == 32 || TypeSize == 64 ||
|
|
TypeSize == 128) &&
|
|
(Alignment >= Granularity || Alignment == 0 || Alignment >= TypeSize / 8))
|
|
return Pass->instrumentAddress(I, InsertBefore, Addr, TypeSize, IsWrite,
|
|
nullptr, UseCalls, Exp);
|
|
Pass->instrumentUnusualSizeOrAlignment(I, InsertBefore, Addr, TypeSize,
|
|
IsWrite, nullptr, UseCalls, Exp);
|
|
}
|
|
|
|
static void instrumentMaskedLoadOrStore(AddressSanitizer *Pass,
|
|
const DataLayout &DL, Type *IntptrTy,
|
|
Value *Mask, Instruction *I,
|
|
Value *Addr, unsigned Alignment,
|
|
unsigned Granularity, uint32_t TypeSize,
|
|
bool IsWrite, Value *SizeArgument,
|
|
bool UseCalls, uint32_t Exp) {
|
|
auto *VTy = cast<PointerType>(Addr->getType())->getElementType();
|
|
uint64_t ElemTypeSize = DL.getTypeStoreSizeInBits(VTy->getScalarType());
|
|
unsigned Num = VTy->getVectorNumElements();
|
|
auto Zero = ConstantInt::get(IntptrTy, 0);
|
|
for (unsigned Idx = 0; Idx < Num; ++Idx) {
|
|
Value *InstrumentedAddress = nullptr;
|
|
Instruction *InsertBefore = I;
|
|
if (auto *Vector = dyn_cast<ConstantVector>(Mask)) {
|
|
// dyn_cast as we might get UndefValue
|
|
if (auto *Masked = dyn_cast<ConstantInt>(Vector->getOperand(Idx))) {
|
|
if (Masked->isZero())
|
|
// Mask is constant false, so no instrumentation needed.
|
|
continue;
|
|
// If we have a true or undef value, fall through to doInstrumentAddress
|
|
// with InsertBefore == I
|
|
}
|
|
} else {
|
|
IRBuilder<> IRB(I);
|
|
Value *MaskElem = IRB.CreateExtractElement(Mask, Idx);
|
|
Instruction *ThenTerm = SplitBlockAndInsertIfThen(MaskElem, I, false);
|
|
InsertBefore = ThenTerm;
|
|
}
|
|
|
|
IRBuilder<> IRB(InsertBefore);
|
|
InstrumentedAddress =
|
|
IRB.CreateGEP(VTy, Addr, {Zero, ConstantInt::get(IntptrTy, Idx)});
|
|
doInstrumentAddress(Pass, I, InsertBefore, InstrumentedAddress, Alignment,
|
|
Granularity, ElemTypeSize, IsWrite, SizeArgument,
|
|
UseCalls, Exp);
|
|
}
|
|
}
|
|
|
|
void AddressSanitizer::instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis,
|
|
Instruction *I, bool UseCalls,
|
|
const DataLayout &DL) {
|
|
bool IsWrite = false;
|
|
unsigned Alignment = 0;
|
|
uint64_t TypeSize = 0;
|
|
Value *MaybeMask = nullptr;
|
|
Value *Addr =
|
|
isInterestingMemoryAccess(I, &IsWrite, &TypeSize, &Alignment, &MaybeMask);
|
|
assert(Addr);
|
|
|
|
// Optimization experiments.
|
|
// The experiments can be used to evaluate potential optimizations that remove
|
|
// instrumentation (assess false negatives). Instead of completely removing
|
|
// some instrumentation, you set Exp to a non-zero value (mask of optimization
|
|
// experiments that want to remove instrumentation of this instruction).
|
|
// If Exp is non-zero, this pass will emit special calls into runtime
|
|
// (e.g. __asan_report_exp_load1 instead of __asan_report_load1). These calls
|
|
// make runtime terminate the program in a special way (with a different
|
|
// exit status). Then you run the new compiler on a buggy corpus, collect
|
|
// the special terminations (ideally, you don't see them at all -- no false
|
|
// negatives) and make the decision on the optimization.
|
|
uint32_t Exp = ClForceExperiment;
|
|
|
|
if (ClOpt && ClOptGlobals) {
|
|
// If initialization order checking is disabled, a simple access to a
|
|
// dynamically initialized global is always valid.
|
|
GlobalVariable *G = dyn_cast<GlobalVariable>(GetUnderlyingObject(Addr, DL));
|
|
if (G && (!ClInitializers || GlobalIsLinkerInitialized(G)) &&
|
|
isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
|
|
NumOptimizedAccessesToGlobalVar++;
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (ClOpt && ClOptStack) {
|
|
// A direct inbounds access to a stack variable is always valid.
|
|
if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) &&
|
|
isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
|
|
NumOptimizedAccessesToStackVar++;
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (IsWrite)
|
|
NumInstrumentedWrites++;
|
|
else
|
|
NumInstrumentedReads++;
|
|
|
|
unsigned Granularity = 1 << Mapping.Scale;
|
|
if (MaybeMask) {
|
|
instrumentMaskedLoadOrStore(this, DL, IntptrTy, MaybeMask, I, Addr,
|
|
Alignment, Granularity, TypeSize, IsWrite,
|
|
nullptr, UseCalls, Exp);
|
|
} else {
|
|
doInstrumentAddress(this, I, I, Addr, Alignment, Granularity, TypeSize,
|
|
IsWrite, nullptr, UseCalls, Exp);
|
|
}
|
|
}
|
|
|
|
Instruction *AddressSanitizer::generateCrashCode(Instruction *InsertBefore,
|
|
Value *Addr, bool IsWrite,
|
|
size_t AccessSizeIndex,
|
|
Value *SizeArgument,
|
|
uint32_t Exp) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
Value *ExpVal = Exp == 0 ? nullptr : ConstantInt::get(IRB.getInt32Ty(), Exp);
|
|
CallInst *Call = nullptr;
|
|
if (SizeArgument) {
|
|
if (Exp == 0)
|
|
Call = IRB.CreateCall(AsanErrorCallbackSized[IsWrite][0],
|
|
{Addr, SizeArgument});
|
|
else
|
|
Call = IRB.CreateCall(AsanErrorCallbackSized[IsWrite][1],
|
|
{Addr, SizeArgument, ExpVal});
|
|
} else {
|
|
if (Exp == 0)
|
|
Call =
|
|
IRB.CreateCall(AsanErrorCallback[IsWrite][0][AccessSizeIndex], Addr);
|
|
else
|
|
Call = IRB.CreateCall(AsanErrorCallback[IsWrite][1][AccessSizeIndex],
|
|
{Addr, ExpVal});
|
|
}
|
|
|
|
// We don't do Call->setDoesNotReturn() because the BB already has
|
|
// UnreachableInst at the end.
|
|
// This EmptyAsm is required to avoid callback merge.
|
|
IRB.CreateCall(EmptyAsm, {});
|
|
return Call;
|
|
}
|
|
|
|
Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
|
|
Value *ShadowValue,
|
|
uint32_t TypeSize) {
|
|
size_t Granularity = static_cast<size_t>(1) << Mapping.Scale;
|
|
// Addr & (Granularity - 1)
|
|
Value *LastAccessedByte =
|
|
IRB.CreateAnd(AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
|
|
// (Addr & (Granularity - 1)) + size - 1
|
|
if (TypeSize / 8 > 1)
|
|
LastAccessedByte = IRB.CreateAdd(
|
|
LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
|
|
// (uint8_t) ((Addr & (Granularity-1)) + size - 1)
|
|
LastAccessedByte =
|
|
IRB.CreateIntCast(LastAccessedByte, ShadowValue->getType(), false);
|
|
// ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
|
|
return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
|
|
}
|
|
|
|
void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
|
|
Instruction *InsertBefore, Value *Addr,
|
|
uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls,
|
|
uint32_t Exp) {
|
|
bool IsMyriad = TargetTriple.getVendor() == llvm::Triple::Myriad;
|
|
|
|
IRBuilder<> IRB(InsertBefore);
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
|
|
|
|
if (UseCalls) {
|
|
if (Exp == 0)
|
|
IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][0][AccessSizeIndex],
|
|
AddrLong);
|
|
else
|
|
IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][1][AccessSizeIndex],
|
|
{AddrLong, ConstantInt::get(IRB.getInt32Ty(), Exp)});
|
|
return;
|
|
}
|
|
|
|
if (IsMyriad) {
|
|
// Strip the cache bit and do range check.
|
|
// AddrLong &= ~kMyriadCacheBitMask32
|
|
AddrLong = IRB.CreateAnd(AddrLong, ~kMyriadCacheBitMask32);
|
|
// Tag = AddrLong >> kMyriadTagShift
|
|
Value *Tag = IRB.CreateLShr(AddrLong, kMyriadTagShift);
|
|
// Tag == kMyriadDDRTag
|
|
Value *TagCheck =
|
|
IRB.CreateICmpEQ(Tag, ConstantInt::get(IntptrTy, kMyriadDDRTag));
|
|
|
|
Instruction *TagCheckTerm =
|
|
SplitBlockAndInsertIfThen(TagCheck, InsertBefore, false,
|
|
MDBuilder(*C).createBranchWeights(1, 100000));
|
|
assert(cast<BranchInst>(TagCheckTerm)->isUnconditional());
|
|
IRB.SetInsertPoint(TagCheckTerm);
|
|
InsertBefore = TagCheckTerm;
|
|
}
|
|
|
|
Type *ShadowTy =
|
|
IntegerType::get(*C, std::max(8U, TypeSize >> Mapping.Scale));
|
|
Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
|
|
Value *ShadowPtr = memToShadow(AddrLong, IRB);
|
|
Value *CmpVal = Constant::getNullValue(ShadowTy);
|
|
Value *ShadowValue =
|
|
IRB.CreateLoad(ShadowTy, IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
|
|
|
|
Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
|
|
size_t Granularity = 1ULL << Mapping.Scale;
|
|
Instruction *CrashTerm = nullptr;
|
|
|
|
if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
|
|
// We use branch weights for the slow path check, to indicate that the slow
|
|
// path is rarely taken. This seems to be the case for SPEC benchmarks.
|
|
Instruction *CheckTerm = SplitBlockAndInsertIfThen(
|
|
Cmp, InsertBefore, false, MDBuilder(*C).createBranchWeights(1, 100000));
|
|
assert(cast<BranchInst>(CheckTerm)->isUnconditional());
|
|
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
|
|
IRB.SetInsertPoint(CheckTerm);
|
|
Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
|
|
if (Recover) {
|
|
CrashTerm = SplitBlockAndInsertIfThen(Cmp2, CheckTerm, false);
|
|
} else {
|
|
BasicBlock *CrashBlock =
|
|
BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
|
|
CrashTerm = new UnreachableInst(*C, CrashBlock);
|
|
BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
|
|
ReplaceInstWithInst(CheckTerm, NewTerm);
|
|
}
|
|
} else {
|
|
CrashTerm = SplitBlockAndInsertIfThen(Cmp, InsertBefore, !Recover);
|
|
}
|
|
|
|
Instruction *Crash = generateCrashCode(CrashTerm, AddrLong, IsWrite,
|
|
AccessSizeIndex, SizeArgument, Exp);
|
|
Crash->setDebugLoc(OrigIns->getDebugLoc());
|
|
}
|
|
|
|
// Instrument unusual size or unusual alignment.
|
|
// We can not do it with a single check, so we do 1-byte check for the first
|
|
// and the last bytes. We call __asan_report_*_n(addr, real_size) to be able
|
|
// to report the actual access size.
|
|
void AddressSanitizer::instrumentUnusualSizeOrAlignment(
|
|
Instruction *I, Instruction *InsertBefore, Value *Addr, uint32_t TypeSize,
|
|
bool IsWrite, Value *SizeArgument, bool UseCalls, uint32_t Exp) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
if (UseCalls) {
|
|
if (Exp == 0)
|
|
IRB.CreateCall(AsanMemoryAccessCallbackSized[IsWrite][0],
|
|
{AddrLong, Size});
|
|
else
|
|
IRB.CreateCall(AsanMemoryAccessCallbackSized[IsWrite][1],
|
|
{AddrLong, Size, ConstantInt::get(IRB.getInt32Ty(), Exp)});
|
|
} else {
|
|
Value *LastByte = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(AddrLong, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
|
|
Addr->getType());
|
|
instrumentAddress(I, InsertBefore, Addr, 8, IsWrite, Size, false, Exp);
|
|
instrumentAddress(I, InsertBefore, LastByte, 8, IsWrite, Size, false, Exp);
|
|
}
|
|
}
|
|
|
|
void ModuleAddressSanitizer::poisonOneInitializer(Function &GlobalInit,
|
|
GlobalValue *ModuleName) {
|
|
// Set up the arguments to our poison/unpoison functions.
|
|
IRBuilder<> IRB(&GlobalInit.front(),
|
|
GlobalInit.front().getFirstInsertionPt());
|
|
|
|
// Add a call to poison all external globals before the given function starts.
|
|
Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy);
|
|
IRB.CreateCall(AsanPoisonGlobals, ModuleNameAddr);
|
|
|
|
// Add calls to unpoison all globals before each return instruction.
|
|
for (auto &BB : GlobalInit.getBasicBlockList())
|
|
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB.getTerminator()))
|
|
CallInst::Create(AsanUnpoisonGlobals, "", RI);
|
|
}
|
|
|
|
void ModuleAddressSanitizer::createInitializerPoisonCalls(
|
|
Module &M, GlobalValue *ModuleName) {
|
|
GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
|
|
if (!GV)
|
|
return;
|
|
|
|
ConstantArray *CA = dyn_cast<ConstantArray>(GV->getInitializer());
|
|
if (!CA)
|
|
return;
|
|
|
|
for (Use &OP : CA->operands()) {
|
|
if (isa<ConstantAggregateZero>(OP)) continue;
|
|
ConstantStruct *CS = cast<ConstantStruct>(OP);
|
|
|
|
// Must have a function or null ptr.
|
|
if (Function *F = dyn_cast<Function>(CS->getOperand(1))) {
|
|
if (F->getName() == kAsanModuleCtorName) continue;
|
|
auto *Priority = cast<ConstantInt>(CS->getOperand(0));
|
|
// Don't instrument CTORs that will run before asan.module_ctor.
|
|
if (Priority->getLimitedValue() <= GetCtorAndDtorPriority(TargetTriple))
|
|
continue;
|
|
poisonOneInitializer(*F, ModuleName);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool ModuleAddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
|
|
Type *Ty = G->getValueType();
|
|
LLVM_DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
|
|
|
|
// FIXME: Metadata should be attched directly to the global directly instead
|
|
// of being added to llvm.asan.globals.
|
|
if (GlobalsMD.get(G).IsBlacklisted) return false;
|
|
if (!Ty->isSized()) return false;
|
|
if (!G->hasInitializer()) return false;
|
|
// Only instrument globals of default address spaces
|
|
if (G->getAddressSpace()) return false;
|
|
if (GlobalWasGeneratedByCompiler(G)) return false; // Our own globals.
|
|
// Two problems with thread-locals:
|
|
// - The address of the main thread's copy can't be computed at link-time.
|
|
// - Need to poison all copies, not just the main thread's one.
|
|
if (G->isThreadLocal()) return false;
|
|
// For now, just ignore this Global if the alignment is large.
|
|
if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false;
|
|
|
|
// For non-COFF targets, only instrument globals known to be defined by this
|
|
// TU.
|
|
// FIXME: We can instrument comdat globals on ELF if we are using the
|
|
// GC-friendly metadata scheme.
|
|
if (!TargetTriple.isOSBinFormatCOFF()) {
|
|
if (!G->hasExactDefinition() || G->hasComdat())
|
|
return false;
|
|
} else {
|
|
// On COFF, don't instrument non-ODR linkages.
|
|
if (G->isInterposable())
|
|
return false;
|
|
}
|
|
|
|
// If a comdat is present, it must have a selection kind that implies ODR
|
|
// semantics: no duplicates, any, or exact match.
|
|
if (Comdat *C = G->getComdat()) {
|
|
switch (C->getSelectionKind()) {
|
|
case Comdat::Any:
|
|
case Comdat::ExactMatch:
|
|
case Comdat::NoDuplicates:
|
|
break;
|
|
case Comdat::Largest:
|
|
case Comdat::SameSize:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (G->hasSection()) {
|
|
StringRef Section = G->getSection();
|
|
|
|
// Globals from llvm.metadata aren't emitted, do not instrument them.
|
|
if (Section == "llvm.metadata") return false;
|
|
// Do not instrument globals from special LLVM sections.
|
|
if (Section.find("__llvm") != StringRef::npos || Section.find("__LLVM") != StringRef::npos) return false;
|
|
|
|
// Do not instrument function pointers to initialization and termination
|
|
// routines: dynamic linker will not properly handle redzones.
|
|
if (Section.startswith(".preinit_array") ||
|
|
Section.startswith(".init_array") ||
|
|
Section.startswith(".fini_array")) {
|
|
return false;
|
|
}
|
|
|
|
// On COFF, if the section name contains '$', it is highly likely that the
|
|
// user is using section sorting to create an array of globals similar to
|
|
// the way initialization callbacks are registered in .init_array and
|
|
// .CRT$XCU. The ATL also registers things in .ATL$__[azm]. Adding redzones
|
|
// to such globals is counterproductive, because the intent is that they
|
|
// will form an array, and out-of-bounds accesses are expected.
|
|
// See https://github.com/google/sanitizers/issues/305
|
|
// and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx
|
|
if (TargetTriple.isOSBinFormatCOFF() && Section.contains('$')) {
|
|
LLVM_DEBUG(dbgs() << "Ignoring global in sorted section (contains '$'): "
|
|
<< *G << "\n");
|
|
return false;
|
|
}
|
|
|
|
if (TargetTriple.isOSBinFormatMachO()) {
|
|
StringRef ParsedSegment, ParsedSection;
|
|
unsigned TAA = 0, StubSize = 0;
|
|
bool TAAParsed;
|
|
std::string ErrorCode = MCSectionMachO::ParseSectionSpecifier(
|
|
Section, ParsedSegment, ParsedSection, TAA, TAAParsed, StubSize);
|
|
assert(ErrorCode.empty() && "Invalid section specifier.");
|
|
|
|
// Ignore the globals from the __OBJC section. The ObjC runtime assumes
|
|
// those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
|
|
// them.
|
|
if (ParsedSegment == "__OBJC" ||
|
|
(ParsedSegment == "__DATA" && ParsedSection.startswith("__objc_"))) {
|
|
LLVM_DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G << "\n");
|
|
return false;
|
|
}
|
|
// See https://github.com/google/sanitizers/issues/32
|
|
// Constant CFString instances are compiled in the following way:
|
|
// -- the string buffer is emitted into
|
|
// __TEXT,__cstring,cstring_literals
|
|
// -- the constant NSConstantString structure referencing that buffer
|
|
// is placed into __DATA,__cfstring
|
|
// Therefore there's no point in placing redzones into __DATA,__cfstring.
|
|
// Moreover, it causes the linker to crash on OS X 10.7
|
|
if (ParsedSegment == "__DATA" && ParsedSection == "__cfstring") {
|
|
LLVM_DEBUG(dbgs() << "Ignoring CFString: " << *G << "\n");
|
|
return false;
|
|
}
|
|
// The linker merges the contents of cstring_literals and removes the
|
|
// trailing zeroes.
|
|
if (ParsedSegment == "__TEXT" && (TAA & MachO::S_CSTRING_LITERALS)) {
|
|
LLVM_DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n");
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// On Mach-O platforms, we emit global metadata in a separate section of the
|
|
// binary in order to allow the linker to properly dead strip. This is only
|
|
// supported on recent versions of ld64.
|
|
bool ModuleAddressSanitizer::ShouldUseMachOGlobalsSection() const {
|
|
if (!TargetTriple.isOSBinFormatMachO())
|
|
return false;
|
|
|
|
if (TargetTriple.isMacOSX() && !TargetTriple.isMacOSXVersionLT(10, 11))
|
|
return true;
|
|
if (TargetTriple.isiOS() /* or tvOS */ && !TargetTriple.isOSVersionLT(9))
|
|
return true;
|
|
if (TargetTriple.isWatchOS() && !TargetTriple.isOSVersionLT(2))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
StringRef ModuleAddressSanitizer::getGlobalMetadataSection() const {
|
|
switch (TargetTriple.getObjectFormat()) {
|
|
case Triple::COFF: return ".ASAN$GL";
|
|
case Triple::ELF: return "asan_globals";
|
|
case Triple::MachO: return "__DATA,__asan_globals,regular";
|
|
case Triple::Wasm:
|
|
case Triple::XCOFF:
|
|
report_fatal_error(
|
|
"ModuleAddressSanitizer not implemented for object file format.");
|
|
case Triple::UnknownObjectFormat:
|
|
break;
|
|
}
|
|
llvm_unreachable("unsupported object format");
|
|
}
|
|
|
|
void ModuleAddressSanitizer::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
|
|
// Declare our poisoning and unpoisoning functions.
|
|
AsanPoisonGlobals =
|
|
M.getOrInsertFunction(kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy);
|
|
AsanUnpoisonGlobals =
|
|
M.getOrInsertFunction(kAsanUnpoisonGlobalsName, IRB.getVoidTy());
|
|
|
|
// Declare functions that register/unregister globals.
|
|
AsanRegisterGlobals = M.getOrInsertFunction(
|
|
kAsanRegisterGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
AsanUnregisterGlobals = M.getOrInsertFunction(
|
|
kAsanUnregisterGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
|
|
// Declare the functions that find globals in a shared object and then invoke
|
|
// the (un)register function on them.
|
|
AsanRegisterImageGlobals = M.getOrInsertFunction(
|
|
kAsanRegisterImageGlobalsName, IRB.getVoidTy(), IntptrTy);
|
|
AsanUnregisterImageGlobals = M.getOrInsertFunction(
|
|
kAsanUnregisterImageGlobalsName, IRB.getVoidTy(), IntptrTy);
|
|
|
|
AsanRegisterElfGlobals =
|
|
M.getOrInsertFunction(kAsanRegisterElfGlobalsName, IRB.getVoidTy(),
|
|
IntptrTy, IntptrTy, IntptrTy);
|
|
AsanUnregisterElfGlobals =
|
|
M.getOrInsertFunction(kAsanUnregisterElfGlobalsName, IRB.getVoidTy(),
|
|
IntptrTy, IntptrTy, IntptrTy);
|
|
}
|
|
|
|
// Put the metadata and the instrumented global in the same group. This ensures
|
|
// that the metadata is discarded if the instrumented global is discarded.
|
|
void ModuleAddressSanitizer::SetComdatForGlobalMetadata(
|
|
GlobalVariable *G, GlobalVariable *Metadata, StringRef InternalSuffix) {
|
|
Module &M = *G->getParent();
|
|
Comdat *C = G->getComdat();
|
|
if (!C) {
|
|
if (!G->hasName()) {
|
|
// If G is unnamed, it must be internal. Give it an artificial name
|
|
// so we can put it in a comdat.
|
|
assert(G->hasLocalLinkage());
|
|
G->setName(Twine(kAsanGenPrefix) + "_anon_global");
|
|
}
|
|
|
|
if (!InternalSuffix.empty() && G->hasLocalLinkage()) {
|
|
std::string Name = G->getName();
|
|
Name += InternalSuffix;
|
|
C = M.getOrInsertComdat(Name);
|
|
} else {
|
|
C = M.getOrInsertComdat(G->getName());
|
|
}
|
|
|
|
// Make this IMAGE_COMDAT_SELECT_NODUPLICATES on COFF. Also upgrade private
|
|
// linkage to internal linkage so that a symbol table entry is emitted. This
|
|
// is necessary in order to create the comdat group.
|
|
if (TargetTriple.isOSBinFormatCOFF()) {
|
|
C->setSelectionKind(Comdat::NoDuplicates);
|
|
if (G->hasPrivateLinkage())
|
|
G->setLinkage(GlobalValue::InternalLinkage);
|
|
}
|
|
G->setComdat(C);
|
|
}
|
|
|
|
assert(G->hasComdat());
|
|
Metadata->setComdat(G->getComdat());
|
|
}
|
|
|
|
// Create a separate metadata global and put it in the appropriate ASan
|
|
// global registration section.
|
|
GlobalVariable *
|
|
ModuleAddressSanitizer::CreateMetadataGlobal(Module &M, Constant *Initializer,
|
|
StringRef OriginalName) {
|
|
auto Linkage = TargetTriple.isOSBinFormatMachO()
|
|
? GlobalVariable::InternalLinkage
|
|
: GlobalVariable::PrivateLinkage;
|
|
GlobalVariable *Metadata = new GlobalVariable(
|
|
M, Initializer->getType(), false, Linkage, Initializer,
|
|
Twine("__asan_global_") + GlobalValue::dropLLVMManglingEscape(OriginalName));
|
|
Metadata->setSection(getGlobalMetadataSection());
|
|
return Metadata;
|
|
}
|
|
|
|
IRBuilder<> ModuleAddressSanitizer::CreateAsanModuleDtor(Module &M) {
|
|
AsanDtorFunction =
|
|
Function::Create(FunctionType::get(Type::getVoidTy(*C), false),
|
|
GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
|
|
BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
|
|
|
|
return IRBuilder<>(ReturnInst::Create(*C, AsanDtorBB));
|
|
}
|
|
|
|
void ModuleAddressSanitizer::InstrumentGlobalsCOFF(
|
|
IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers) {
|
|
assert(ExtendedGlobals.size() == MetadataInitializers.size());
|
|
auto &DL = M.getDataLayout();
|
|
|
|
for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
|
|
Constant *Initializer = MetadataInitializers[i];
|
|
GlobalVariable *G = ExtendedGlobals[i];
|
|
GlobalVariable *Metadata =
|
|
CreateMetadataGlobal(M, Initializer, G->getName());
|
|
|
|
// The MSVC linker always inserts padding when linking incrementally. We
|
|
// cope with that by aligning each struct to its size, which must be a power
|
|
// of two.
|
|
unsigned SizeOfGlobalStruct = DL.getTypeAllocSize(Initializer->getType());
|
|
assert(isPowerOf2_32(SizeOfGlobalStruct) &&
|
|
"global metadata will not be padded appropriately");
|
|
Metadata->setAlignment(assumeAligned(SizeOfGlobalStruct));
|
|
|
|
SetComdatForGlobalMetadata(G, Metadata, "");
|
|
}
|
|
}
|
|
|
|
void ModuleAddressSanitizer::InstrumentGlobalsELF(
|
|
IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers,
|
|
const std::string &UniqueModuleId) {
|
|
assert(ExtendedGlobals.size() == MetadataInitializers.size());
|
|
|
|
SmallVector<GlobalValue *, 16> MetadataGlobals(ExtendedGlobals.size());
|
|
for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
|
|
GlobalVariable *G = ExtendedGlobals[i];
|
|
GlobalVariable *Metadata =
|
|
CreateMetadataGlobal(M, MetadataInitializers[i], G->getName());
|
|
MDNode *MD = MDNode::get(M.getContext(), ValueAsMetadata::get(G));
|
|
Metadata->setMetadata(LLVMContext::MD_associated, MD);
|
|
MetadataGlobals[i] = Metadata;
|
|
|
|
SetComdatForGlobalMetadata(G, Metadata, UniqueModuleId);
|
|
}
|
|
|
|
// Update llvm.compiler.used, adding the new metadata globals. This is
|
|
// needed so that during LTO these variables stay alive.
|
|
if (!MetadataGlobals.empty())
|
|
appendToCompilerUsed(M, MetadataGlobals);
|
|
|
|
// RegisteredFlag serves two purposes. First, we can pass it to dladdr()
|
|
// to look up the loaded image that contains it. Second, we can store in it
|
|
// whether registration has already occurred, to prevent duplicate
|
|
// registration.
|
|
//
|
|
// Common linkage ensures that there is only one global per shared library.
|
|
GlobalVariable *RegisteredFlag = new GlobalVariable(
|
|
M, IntptrTy, false, GlobalVariable::CommonLinkage,
|
|
ConstantInt::get(IntptrTy, 0), kAsanGlobalsRegisteredFlagName);
|
|
RegisteredFlag->setVisibility(GlobalVariable::HiddenVisibility);
|
|
|
|
// Create start and stop symbols.
|
|
GlobalVariable *StartELFMetadata = new GlobalVariable(
|
|
M, IntptrTy, false, GlobalVariable::ExternalWeakLinkage, nullptr,
|
|
"__start_" + getGlobalMetadataSection());
|
|
StartELFMetadata->setVisibility(GlobalVariable::HiddenVisibility);
|
|
GlobalVariable *StopELFMetadata = new GlobalVariable(
|
|
M, IntptrTy, false, GlobalVariable::ExternalWeakLinkage, nullptr,
|
|
"__stop_" + getGlobalMetadataSection());
|
|
StopELFMetadata->setVisibility(GlobalVariable::HiddenVisibility);
|
|
|
|
// Create a call to register the globals with the runtime.
|
|
IRB.CreateCall(AsanRegisterElfGlobals,
|
|
{IRB.CreatePointerCast(RegisteredFlag, IntptrTy),
|
|
IRB.CreatePointerCast(StartELFMetadata, IntptrTy),
|
|
IRB.CreatePointerCast(StopELFMetadata, IntptrTy)});
|
|
|
|
// We also need to unregister globals at the end, e.g., when a shared library
|
|
// gets closed.
|
|
IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
|
|
IRB_Dtor.CreateCall(AsanUnregisterElfGlobals,
|
|
{IRB.CreatePointerCast(RegisteredFlag, IntptrTy),
|
|
IRB.CreatePointerCast(StartELFMetadata, IntptrTy),
|
|
IRB.CreatePointerCast(StopELFMetadata, IntptrTy)});
|
|
}
|
|
|
|
void ModuleAddressSanitizer::InstrumentGlobalsMachO(
|
|
IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers) {
|
|
assert(ExtendedGlobals.size() == MetadataInitializers.size());
|
|
|
|
// On recent Mach-O platforms, use a structure which binds the liveness of
|
|
// the global variable to the metadata struct. Keep the list of "Liveness" GV
|
|
// created to be added to llvm.compiler.used
|
|
StructType *LivenessTy = StructType::get(IntptrTy, IntptrTy);
|
|
SmallVector<GlobalValue *, 16> LivenessGlobals(ExtendedGlobals.size());
|
|
|
|
for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
|
|
Constant *Initializer = MetadataInitializers[i];
|
|
GlobalVariable *G = ExtendedGlobals[i];
|
|
GlobalVariable *Metadata =
|
|
CreateMetadataGlobal(M, Initializer, G->getName());
|
|
|
|
// On recent Mach-O platforms, we emit the global metadata in a way that
|
|
// allows the linker to properly strip dead globals.
|
|
auto LivenessBinder =
|
|
ConstantStruct::get(LivenessTy, Initializer->getAggregateElement(0u),
|
|
ConstantExpr::getPointerCast(Metadata, IntptrTy));
|
|
GlobalVariable *Liveness = new GlobalVariable(
|
|
M, LivenessTy, false, GlobalVariable::InternalLinkage, LivenessBinder,
|
|
Twine("__asan_binder_") + G->getName());
|
|
Liveness->setSection("__DATA,__asan_liveness,regular,live_support");
|
|
LivenessGlobals[i] = Liveness;
|
|
}
|
|
|
|
// Update llvm.compiler.used, adding the new liveness globals. This is
|
|
// needed so that during LTO these variables stay alive. The alternative
|
|
// would be to have the linker handling the LTO symbols, but libLTO
|
|
// current API does not expose access to the section for each symbol.
|
|
if (!LivenessGlobals.empty())
|
|
appendToCompilerUsed(M, LivenessGlobals);
|
|
|
|
// RegisteredFlag serves two purposes. First, we can pass it to dladdr()
|
|
// to look up the loaded image that contains it. Second, we can store in it
|
|
// whether registration has already occurred, to prevent duplicate
|
|
// registration.
|
|
//
|
|
// common linkage ensures that there is only one global per shared library.
|
|
GlobalVariable *RegisteredFlag = new GlobalVariable(
|
|
M, IntptrTy, false, GlobalVariable::CommonLinkage,
|
|
ConstantInt::get(IntptrTy, 0), kAsanGlobalsRegisteredFlagName);
|
|
RegisteredFlag->setVisibility(GlobalVariable::HiddenVisibility);
|
|
|
|
IRB.CreateCall(AsanRegisterImageGlobals,
|
|
{IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
|
|
|
|
// We also need to unregister globals at the end, e.g., when a shared library
|
|
// gets closed.
|
|
IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
|
|
IRB_Dtor.CreateCall(AsanUnregisterImageGlobals,
|
|
{IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
|
|
}
|
|
|
|
void ModuleAddressSanitizer::InstrumentGlobalsWithMetadataArray(
|
|
IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
|
|
ArrayRef<Constant *> MetadataInitializers) {
|
|
assert(ExtendedGlobals.size() == MetadataInitializers.size());
|
|
unsigned N = ExtendedGlobals.size();
|
|
assert(N > 0);
|
|
|
|
// On platforms that don't have a custom metadata section, we emit an array
|
|
// of global metadata structures.
|
|
ArrayType *ArrayOfGlobalStructTy =
|
|
ArrayType::get(MetadataInitializers[0]->getType(), N);
|
|
auto AllGlobals = new GlobalVariable(
|
|
M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
|
|
ConstantArray::get(ArrayOfGlobalStructTy, MetadataInitializers), "");
|
|
if (Mapping.Scale > 3)
|
|
AllGlobals->setAlignment(Align(1ULL << Mapping.Scale));
|
|
|
|
IRB.CreateCall(AsanRegisterGlobals,
|
|
{IRB.CreatePointerCast(AllGlobals, IntptrTy),
|
|
ConstantInt::get(IntptrTy, N)});
|
|
|
|
// We also need to unregister globals at the end, e.g., when a shared library
|
|
// gets closed.
|
|
IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
|
|
IRB_Dtor.CreateCall(AsanUnregisterGlobals,
|
|
{IRB.CreatePointerCast(AllGlobals, IntptrTy),
|
|
ConstantInt::get(IntptrTy, N)});
|
|
}
|
|
|
|
// This function replaces all global variables with new variables that have
|
|
// trailing redzones. It also creates a function that poisons
|
|
// redzones and inserts this function into llvm.global_ctors.
|
|
// Sets *CtorComdat to true if the global registration code emitted into the
|
|
// asan constructor is comdat-compatible.
|
|
bool ModuleAddressSanitizer::InstrumentGlobals(IRBuilder<> &IRB, Module &M,
|
|
bool *CtorComdat) {
|
|
*CtorComdat = false;
|
|
|
|
SmallVector<GlobalVariable *, 16> GlobalsToChange;
|
|
|
|
for (auto &G : M.globals()) {
|
|
if (ShouldInstrumentGlobal(&G)) GlobalsToChange.push_back(&G);
|
|
}
|
|
|
|
size_t n = GlobalsToChange.size();
|
|
if (n == 0) {
|
|
*CtorComdat = true;
|
|
return false;
|
|
}
|
|
|
|
auto &DL = M.getDataLayout();
|
|
|
|
// A global is described by a structure
|
|
// size_t beg;
|
|
// size_t size;
|
|
// size_t size_with_redzone;
|
|
// const char *name;
|
|
// const char *module_name;
|
|
// size_t has_dynamic_init;
|
|
// void *source_location;
|
|
// size_t odr_indicator;
|
|
// We initialize an array of such structures and pass it to a run-time call.
|
|
StructType *GlobalStructTy =
|
|
StructType::get(IntptrTy, IntptrTy, IntptrTy, IntptrTy, IntptrTy,
|
|
IntptrTy, IntptrTy, IntptrTy);
|
|
SmallVector<GlobalVariable *, 16> NewGlobals(n);
|
|
SmallVector<Constant *, 16> Initializers(n);
|
|
|
|
bool HasDynamicallyInitializedGlobals = false;
|
|
|
|
// We shouldn't merge same module names, as this string serves as unique
|
|
// module ID in runtime.
|
|
GlobalVariable *ModuleName = createPrivateGlobalForString(
|
|
M, M.getModuleIdentifier(), /*AllowMerging*/ false, kAsanGenPrefix);
|
|
|
|
for (size_t i = 0; i < n; i++) {
|
|
static const uint64_t kMaxGlobalRedzone = 1 << 18;
|
|
GlobalVariable *G = GlobalsToChange[i];
|
|
|
|
// FIXME: Metadata should be attched directly to the global directly instead
|
|
// of being added to llvm.asan.globals.
|
|
auto MD = GlobalsMD.get(G);
|
|
StringRef NameForGlobal = G->getName();
|
|
// Create string holding the global name (use global name from metadata
|
|
// if it's available, otherwise just write the name of global variable).
|
|
GlobalVariable *Name = createPrivateGlobalForString(
|
|
M, MD.Name.empty() ? NameForGlobal : MD.Name,
|
|
/*AllowMerging*/ true, kAsanGenPrefix);
|
|
|
|
Type *Ty = G->getValueType();
|
|
uint64_t SizeInBytes = DL.getTypeAllocSize(Ty);
|
|
uint64_t MinRZ = MinRedzoneSizeForGlobal();
|
|
// MinRZ <= RZ <= kMaxGlobalRedzone
|
|
// and trying to make RZ to be ~ 1/4 of SizeInBytes.
|
|
uint64_t RZ = std::max(
|
|
MinRZ, std::min(kMaxGlobalRedzone, (SizeInBytes / MinRZ / 4) * MinRZ));
|
|
uint64_t RightRedzoneSize = RZ;
|
|
// Round up to MinRZ
|
|
if (SizeInBytes % MinRZ) RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ);
|
|
assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0);
|
|
Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
|
|
|
|
StructType *NewTy = StructType::get(Ty, RightRedZoneTy);
|
|
Constant *NewInitializer = ConstantStruct::get(
|
|
NewTy, G->getInitializer(), Constant::getNullValue(RightRedZoneTy));
|
|
|
|
// Create a new global variable with enough space for a redzone.
|
|
GlobalValue::LinkageTypes Linkage = G->getLinkage();
|
|
if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage)
|
|
Linkage = GlobalValue::InternalLinkage;
|
|
GlobalVariable *NewGlobal =
|
|
new GlobalVariable(M, NewTy, G->isConstant(), Linkage, NewInitializer,
|
|
"", G, G->getThreadLocalMode());
|
|
NewGlobal->copyAttributesFrom(G);
|
|
NewGlobal->setComdat(G->getComdat());
|
|
NewGlobal->setAlignment(MaybeAlign(MinRZ));
|
|
// Don't fold globals with redzones. ODR violation detector and redzone
|
|
// poisoning implicitly creates a dependence on the global's address, so it
|
|
// is no longer valid for it to be marked unnamed_addr.
|
|
NewGlobal->setUnnamedAddr(GlobalValue::UnnamedAddr::None);
|
|
|
|
// Move null-terminated C strings to "__asan_cstring" section on Darwin.
|
|
if (TargetTriple.isOSBinFormatMachO() && !G->hasSection() &&
|
|
G->isConstant()) {
|
|
auto Seq = dyn_cast<ConstantDataSequential>(G->getInitializer());
|
|
if (Seq && Seq->isCString())
|
|
NewGlobal->setSection("__TEXT,__asan_cstring,regular");
|
|
}
|
|
|
|
// Transfer the debug info. The payload starts at offset zero so we can
|
|
// copy the debug info over as is.
|
|
SmallVector<DIGlobalVariableExpression *, 1> GVs;
|
|
G->getDebugInfo(GVs);
|
|
for (auto *GV : GVs)
|
|
NewGlobal->addDebugInfo(GV);
|
|
|
|
Value *Indices2[2];
|
|
Indices2[0] = IRB.getInt32(0);
|
|
Indices2[1] = IRB.getInt32(0);
|
|
|
|
G->replaceAllUsesWith(
|
|
ConstantExpr::getGetElementPtr(NewTy, NewGlobal, Indices2, true));
|
|
NewGlobal->takeName(G);
|
|
G->eraseFromParent();
|
|
NewGlobals[i] = NewGlobal;
|
|
|
|
Constant *SourceLoc;
|
|
if (!MD.SourceLoc.empty()) {
|
|
auto SourceLocGlobal = createPrivateGlobalForSourceLoc(M, MD.SourceLoc);
|
|
SourceLoc = ConstantExpr::getPointerCast(SourceLocGlobal, IntptrTy);
|
|
} else {
|
|
SourceLoc = ConstantInt::get(IntptrTy, 0);
|
|
}
|
|
|
|
Constant *ODRIndicator = ConstantExpr::getNullValue(IRB.getInt8PtrTy());
|
|
GlobalValue *InstrumentedGlobal = NewGlobal;
|
|
|
|
bool CanUsePrivateAliases =
|
|
TargetTriple.isOSBinFormatELF() || TargetTriple.isOSBinFormatMachO() ||
|
|
TargetTriple.isOSBinFormatWasm();
|
|
if (CanUsePrivateAliases && UsePrivateAlias) {
|
|
// Create local alias for NewGlobal to avoid crash on ODR between
|
|
// instrumented and non-instrumented libraries.
|
|
InstrumentedGlobal =
|
|
GlobalAlias::create(GlobalValue::PrivateLinkage, "", NewGlobal);
|
|
}
|
|
|
|
// ODR should not happen for local linkage.
|
|
if (NewGlobal->hasLocalLinkage()) {
|
|
ODRIndicator = ConstantExpr::getIntToPtr(ConstantInt::get(IntptrTy, -1),
|
|
IRB.getInt8PtrTy());
|
|
} else if (UseOdrIndicator) {
|
|
// With local aliases, we need to provide another externally visible
|
|
// symbol __odr_asan_XXX to detect ODR violation.
|
|
auto *ODRIndicatorSym =
|
|
new GlobalVariable(M, IRB.getInt8Ty(), false, Linkage,
|
|
Constant::getNullValue(IRB.getInt8Ty()),
|
|
kODRGenPrefix + NameForGlobal, nullptr,
|
|
NewGlobal->getThreadLocalMode());
|
|
|
|
// Set meaningful attributes for indicator symbol.
|
|
ODRIndicatorSym->setVisibility(NewGlobal->getVisibility());
|
|
ODRIndicatorSym->setDLLStorageClass(NewGlobal->getDLLStorageClass());
|
|
ODRIndicatorSym->setAlignment(Align::None());
|
|
ODRIndicator = ODRIndicatorSym;
|
|
}
|
|
|
|
Constant *Initializer = ConstantStruct::get(
|
|
GlobalStructTy,
|
|
ConstantExpr::getPointerCast(InstrumentedGlobal, IntptrTy),
|
|
ConstantInt::get(IntptrTy, SizeInBytes),
|
|
ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
|
|
ConstantExpr::getPointerCast(Name, IntptrTy),
|
|
ConstantExpr::getPointerCast(ModuleName, IntptrTy),
|
|
ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc,
|
|
ConstantExpr::getPointerCast(ODRIndicator, IntptrTy));
|
|
|
|
if (ClInitializers && MD.IsDynInit) HasDynamicallyInitializedGlobals = true;
|
|
|
|
LLVM_DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
|
|
|
|
Initializers[i] = Initializer;
|
|
}
|
|
|
|
// Add instrumented globals to llvm.compiler.used list to avoid LTO from
|
|
// ConstantMerge'ing them.
|
|
SmallVector<GlobalValue *, 16> GlobalsToAddToUsedList;
|
|
for (size_t i = 0; i < n; i++) {
|
|
GlobalVariable *G = NewGlobals[i];
|
|
if (G->getName().empty()) continue;
|
|
GlobalsToAddToUsedList.push_back(G);
|
|
}
|
|
appendToCompilerUsed(M, ArrayRef<GlobalValue *>(GlobalsToAddToUsedList));
|
|
|
|
std::string ELFUniqueModuleId =
|
|
(UseGlobalsGC && TargetTriple.isOSBinFormatELF()) ? getUniqueModuleId(&M)
|
|
: "";
|
|
|
|
if (!ELFUniqueModuleId.empty()) {
|
|
InstrumentGlobalsELF(IRB, M, NewGlobals, Initializers, ELFUniqueModuleId);
|
|
*CtorComdat = true;
|
|
} else if (UseGlobalsGC && TargetTriple.isOSBinFormatCOFF()) {
|
|
InstrumentGlobalsCOFF(IRB, M, NewGlobals, Initializers);
|
|
} else if (UseGlobalsGC && ShouldUseMachOGlobalsSection()) {
|
|
InstrumentGlobalsMachO(IRB, M, NewGlobals, Initializers);
|
|
} else {
|
|
InstrumentGlobalsWithMetadataArray(IRB, M, NewGlobals, Initializers);
|
|
}
|
|
|
|
// Create calls for poisoning before initializers run and unpoisoning after.
|
|
if (HasDynamicallyInitializedGlobals)
|
|
createInitializerPoisonCalls(M, ModuleName);
|
|
|
|
LLVM_DEBUG(dbgs() << M);
|
|
return true;
|
|
}
|
|
|
|
int ModuleAddressSanitizer::GetAsanVersion(const Module &M) const {
|
|
int LongSize = M.getDataLayout().getPointerSizeInBits();
|
|
bool isAndroid = Triple(M.getTargetTriple()).isAndroid();
|
|
int Version = 8;
|
|
// 32-bit Android is one version ahead because of the switch to dynamic
|
|
// shadow.
|
|
Version += (LongSize == 32 && isAndroid);
|
|
return Version;
|
|
}
|
|
|
|
bool ModuleAddressSanitizer::instrumentModule(Module &M) {
|
|
initializeCallbacks(M);
|
|
|
|
if (CompileKernel)
|
|
return false;
|
|
|
|
// Create a module constructor. A destructor is created lazily because not all
|
|
// platforms, and not all modules need it.
|
|
std::string AsanVersion = std::to_string(GetAsanVersion(M));
|
|
std::string VersionCheckName =
|
|
ClInsertVersionCheck ? (kAsanVersionCheckNamePrefix + AsanVersion) : "";
|
|
std::tie(AsanCtorFunction, std::ignore) = createSanitizerCtorAndInitFunctions(
|
|
M, kAsanModuleCtorName, kAsanInitName, /*InitArgTypes=*/{},
|
|
/*InitArgs=*/{}, VersionCheckName);
|
|
|
|
bool CtorComdat = true;
|
|
// TODO(glider): temporarily disabled globals instrumentation for KASan.
|
|
if (ClGlobals) {
|
|
IRBuilder<> IRB(AsanCtorFunction->getEntryBlock().getTerminator());
|
|
InstrumentGlobals(IRB, M, &CtorComdat);
|
|
}
|
|
|
|
const uint64_t Priority = GetCtorAndDtorPriority(TargetTriple);
|
|
|
|
// Put the constructor and destructor in comdat if both
|
|
// (1) global instrumentation is not TU-specific
|
|
// (2) target is ELF.
|
|
if (UseCtorComdat && TargetTriple.isOSBinFormatELF() && CtorComdat) {
|
|
AsanCtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleCtorName));
|
|
appendToGlobalCtors(M, AsanCtorFunction, Priority, AsanCtorFunction);
|
|
if (AsanDtorFunction) {
|
|
AsanDtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleDtorName));
|
|
appendToGlobalDtors(M, AsanDtorFunction, Priority, AsanDtorFunction);
|
|
}
|
|
} else {
|
|
appendToGlobalCtors(M, AsanCtorFunction, Priority);
|
|
if (AsanDtorFunction)
|
|
appendToGlobalDtors(M, AsanDtorFunction, Priority);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void AddressSanitizer::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
// Create __asan_report* callbacks.
|
|
// IsWrite, TypeSize and Exp are encoded in the function name.
|
|
for (int Exp = 0; Exp < 2; Exp++) {
|
|
for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
|
|
const std::string TypeStr = AccessIsWrite ? "store" : "load";
|
|
const std::string ExpStr = Exp ? "exp_" : "";
|
|
const std::string EndingStr = Recover ? "_noabort" : "";
|
|
|
|
SmallVector<Type *, 3> Args2 = {IntptrTy, IntptrTy};
|
|
SmallVector<Type *, 2> Args1{1, IntptrTy};
|
|
if (Exp) {
|
|
Type *ExpType = Type::getInt32Ty(*C);
|
|
Args2.push_back(ExpType);
|
|
Args1.push_back(ExpType);
|
|
}
|
|
AsanErrorCallbackSized[AccessIsWrite][Exp] = M.getOrInsertFunction(
|
|
kAsanReportErrorTemplate + ExpStr + TypeStr + "_n" + EndingStr,
|
|
FunctionType::get(IRB.getVoidTy(), Args2, false));
|
|
|
|
AsanMemoryAccessCallbackSized[AccessIsWrite][Exp] = M.getOrInsertFunction(
|
|
ClMemoryAccessCallbackPrefix + ExpStr + TypeStr + "N" + EndingStr,
|
|
FunctionType::get(IRB.getVoidTy(), Args2, false));
|
|
|
|
for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
|
|
AccessSizeIndex++) {
|
|
const std::string Suffix = TypeStr + itostr(1ULL << AccessSizeIndex);
|
|
AsanErrorCallback[AccessIsWrite][Exp][AccessSizeIndex] =
|
|
M.getOrInsertFunction(
|
|
kAsanReportErrorTemplate + ExpStr + Suffix + EndingStr,
|
|
FunctionType::get(IRB.getVoidTy(), Args1, false));
|
|
|
|
AsanMemoryAccessCallback[AccessIsWrite][Exp][AccessSizeIndex] =
|
|
M.getOrInsertFunction(
|
|
ClMemoryAccessCallbackPrefix + ExpStr + Suffix + EndingStr,
|
|
FunctionType::get(IRB.getVoidTy(), Args1, false));
|
|
}
|
|
}
|
|
}
|
|
|
|
const std::string MemIntrinCallbackPrefix =
|
|
CompileKernel ? std::string("") : ClMemoryAccessCallbackPrefix;
|
|
AsanMemmove = M.getOrInsertFunction(MemIntrinCallbackPrefix + "memmove",
|
|
IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IntptrTy);
|
|
AsanMemcpy = M.getOrInsertFunction(MemIntrinCallbackPrefix + "memcpy",
|
|
IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IntptrTy);
|
|
AsanMemset = M.getOrInsertFunction(MemIntrinCallbackPrefix + "memset",
|
|
IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
|
|
IRB.getInt32Ty(), IntptrTy);
|
|
|
|
AsanHandleNoReturnFunc =
|
|
M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy());
|
|
|
|
AsanPtrCmpFunction =
|
|
M.getOrInsertFunction(kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
AsanPtrSubFunction =
|
|
M.getOrInsertFunction(kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
// We insert an empty inline asm after __asan_report* to avoid callback merge.
|
|
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
|
|
StringRef(""), StringRef(""),
|
|
/*hasSideEffects=*/true);
|
|
if (Mapping.InGlobal)
|
|
AsanShadowGlobal = M.getOrInsertGlobal("__asan_shadow",
|
|
ArrayType::get(IRB.getInt8Ty(), 0));
|
|
}
|
|
|
|
bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
|
|
// For each NSObject descendant having a +load method, this method is invoked
|
|
// by the ObjC runtime before any of the static constructors is called.
|
|
// Therefore we need to instrument such methods with a call to __asan_init
|
|
// at the beginning in order to initialize our runtime before any access to
|
|
// the shadow memory.
|
|
// We cannot just ignore these methods, because they may call other
|
|
// instrumented functions.
|
|
if (F.getName().find(" load]") != std::string::npos) {
|
|
FunctionCallee AsanInitFunction =
|
|
declareSanitizerInitFunction(*F.getParent(), kAsanInitName, {});
|
|
IRBuilder<> IRB(&F.front(), F.front().begin());
|
|
IRB.CreateCall(AsanInitFunction, {});
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void AddressSanitizer::maybeInsertDynamicShadowAtFunctionEntry(Function &F) {
|
|
// Generate code only when dynamic addressing is needed.
|
|
if (Mapping.Offset != kDynamicShadowSentinel)
|
|
return;
|
|
|
|
IRBuilder<> IRB(&F.front().front());
|
|
if (Mapping.InGlobal) {
|
|
if (ClWithIfuncSuppressRemat) {
|
|
// An empty inline asm with input reg == output reg.
|
|
// An opaque pointer-to-int cast, basically.
|
|
InlineAsm *Asm = InlineAsm::get(
|
|
FunctionType::get(IntptrTy, {AsanShadowGlobal->getType()}, false),
|
|
StringRef(""), StringRef("=r,0"),
|
|
/*hasSideEffects=*/false);
|
|
LocalDynamicShadow =
|
|
IRB.CreateCall(Asm, {AsanShadowGlobal}, ".asan.shadow");
|
|
} else {
|
|
LocalDynamicShadow =
|
|
IRB.CreatePointerCast(AsanShadowGlobal, IntptrTy, ".asan.shadow");
|
|
}
|
|
} else {
|
|
Value *GlobalDynamicAddress = F.getParent()->getOrInsertGlobal(
|
|
kAsanShadowMemoryDynamicAddress, IntptrTy);
|
|
LocalDynamicShadow = IRB.CreateLoad(IntptrTy, GlobalDynamicAddress);
|
|
}
|
|
}
|
|
|
|
void AddressSanitizer::markEscapedLocalAllocas(Function &F) {
|
|
// Find the one possible call to llvm.localescape and pre-mark allocas passed
|
|
// to it as uninteresting. This assumes we haven't started processing allocas
|
|
// yet. This check is done up front because iterating the use list in
|
|
// isInterestingAlloca would be algorithmically slower.
|
|
assert(ProcessedAllocas.empty() && "must process localescape before allocas");
|
|
|
|
// Try to get the declaration of llvm.localescape. If it's not in the module,
|
|
// we can exit early.
|
|
if (!F.getParent()->getFunction("llvm.localescape")) return;
|
|
|
|
// Look for a call to llvm.localescape call in the entry block. It can't be in
|
|
// any other block.
|
|
for (Instruction &I : F.getEntryBlock()) {
|
|
IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
|
|
if (II && II->getIntrinsicID() == Intrinsic::localescape) {
|
|
// We found a call. Mark all the allocas passed in as uninteresting.
|
|
for (Value *Arg : II->arg_operands()) {
|
|
AllocaInst *AI = dyn_cast<AllocaInst>(Arg->stripPointerCasts());
|
|
assert(AI && AI->isStaticAlloca() &&
|
|
"non-static alloca arg to localescape");
|
|
ProcessedAllocas[AI] = false;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
bool AddressSanitizer::instrumentFunction(Function &F,
|
|
const TargetLibraryInfo *TLI) {
|
|
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
|
|
if (!ClDebugFunc.empty() && ClDebugFunc == F.getName()) return false;
|
|
if (F.getName().startswith("__asan_")) return false;
|
|
|
|
bool FunctionModified = false;
|
|
|
|
// If needed, insert __asan_init before checking for SanitizeAddress attr.
|
|
// This function needs to be called even if the function body is not
|
|
// instrumented.
|
|
if (maybeInsertAsanInitAtFunctionEntry(F))
|
|
FunctionModified = true;
|
|
|
|
// Leave if the function doesn't need instrumentation.
|
|
if (!F.hasFnAttribute(Attribute::SanitizeAddress)) return FunctionModified;
|
|
|
|
LLVM_DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
|
|
|
|
initializeCallbacks(*F.getParent());
|
|
|
|
FunctionStateRAII CleanupObj(this);
|
|
|
|
maybeInsertDynamicShadowAtFunctionEntry(F);
|
|
|
|
// We can't instrument allocas used with llvm.localescape. Only static allocas
|
|
// can be passed to that intrinsic.
|
|
markEscapedLocalAllocas(F);
|
|
|
|
// We want to instrument every address only once per basic block (unless there
|
|
// are calls between uses).
|
|
SmallPtrSet<Value *, 16> TempsToInstrument;
|
|
SmallVector<Instruction *, 16> ToInstrument;
|
|
SmallVector<Instruction *, 8> NoReturnCalls;
|
|
SmallVector<BasicBlock *, 16> AllBlocks;
|
|
SmallVector<Instruction *, 16> PointerComparisonsOrSubtracts;
|
|
int NumAllocas = 0;
|
|
bool IsWrite;
|
|
unsigned Alignment;
|
|
uint64_t TypeSize;
|
|
|
|
// Fill the set of memory operations to instrument.
|
|
for (auto &BB : F) {
|
|
AllBlocks.push_back(&BB);
|
|
TempsToInstrument.clear();
|
|
int NumInsnsPerBB = 0;
|
|
for (auto &Inst : BB) {
|
|
if (LooksLikeCodeInBug11395(&Inst)) return false;
|
|
Value *MaybeMask = nullptr;
|
|
if (Value *Addr = isInterestingMemoryAccess(&Inst, &IsWrite, &TypeSize,
|
|
&Alignment, &MaybeMask)) {
|
|
if (ClOpt && ClOptSameTemp) {
|
|
// If we have a mask, skip instrumentation if we've already
|
|
// instrumented the full object. But don't add to TempsToInstrument
|
|
// because we might get another load/store with a different mask.
|
|
if (MaybeMask) {
|
|
if (TempsToInstrument.count(Addr))
|
|
continue; // We've seen this (whole) temp in the current BB.
|
|
} else {
|
|
if (!TempsToInstrument.insert(Addr).second)
|
|
continue; // We've seen this temp in the current BB.
|
|
}
|
|
}
|
|
} else if (((ClInvalidPointerPairs || ClInvalidPointerCmp) &&
|
|
isInterestingPointerComparison(&Inst)) ||
|
|
((ClInvalidPointerPairs || ClInvalidPointerSub) &&
|
|
isInterestingPointerSubtraction(&Inst))) {
|
|
PointerComparisonsOrSubtracts.push_back(&Inst);
|
|
continue;
|
|
} else if (isa<MemIntrinsic>(Inst)) {
|
|
// ok, take it.
|
|
} else {
|
|
if (isa<AllocaInst>(Inst)) NumAllocas++;
|
|
CallSite CS(&Inst);
|
|
if (CS) {
|
|
// A call inside BB.
|
|
TempsToInstrument.clear();
|
|
if (CS.doesNotReturn() && !CS->hasMetadata("nosanitize"))
|
|
NoReturnCalls.push_back(CS.getInstruction());
|
|
}
|
|
if (CallInst *CI = dyn_cast<CallInst>(&Inst))
|
|
maybeMarkSanitizerLibraryCallNoBuiltin(CI, TLI);
|
|
continue;
|
|
}
|
|
ToInstrument.push_back(&Inst);
|
|
NumInsnsPerBB++;
|
|
if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB) break;
|
|
}
|
|
}
|
|
|
|
bool UseCalls =
|
|
(ClInstrumentationWithCallsThreshold >= 0 &&
|
|
ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold);
|
|
const DataLayout &DL = F.getParent()->getDataLayout();
|
|
ObjectSizeOpts ObjSizeOpts;
|
|
ObjSizeOpts.RoundToAlign = true;
|
|
ObjectSizeOffsetVisitor ObjSizeVis(DL, TLI, F.getContext(), ObjSizeOpts);
|
|
|
|
// Instrument.
|
|
int NumInstrumented = 0;
|
|
for (auto Inst : ToInstrument) {
|
|
if (ClDebugMin < 0 || ClDebugMax < 0 ||
|
|
(NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
|
|
if (isInterestingMemoryAccess(Inst, &IsWrite, &TypeSize, &Alignment))
|
|
instrumentMop(ObjSizeVis, Inst, UseCalls,
|
|
F.getParent()->getDataLayout());
|
|
else
|
|
instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
|
|
}
|
|
NumInstrumented++;
|
|
}
|
|
|
|
FunctionStackPoisoner FSP(F, *this);
|
|
bool ChangedStack = FSP.runOnFunction();
|
|
|
|
// We must unpoison the stack before NoReturn calls (throw, _exit, etc).
|
|
// See e.g. https://github.com/google/sanitizers/issues/37
|
|
for (auto CI : NoReturnCalls) {
|
|
IRBuilder<> IRB(CI);
|
|
IRB.CreateCall(AsanHandleNoReturnFunc, {});
|
|
}
|
|
|
|
for (auto Inst : PointerComparisonsOrSubtracts) {
|
|
instrumentPointerComparisonOrSubtraction(Inst);
|
|
NumInstrumented++;
|
|
}
|
|
|
|
if (NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty())
|
|
FunctionModified = true;
|
|
|
|
LLVM_DEBUG(dbgs() << "ASAN done instrumenting: " << FunctionModified << " "
|
|
<< F << "\n");
|
|
|
|
return FunctionModified;
|
|
}
|
|
|
|
// Workaround for bug 11395: we don't want to instrument stack in functions
|
|
// with large assembly blobs (32-bit only), otherwise reg alloc may crash.
|
|
// FIXME: remove once the bug 11395 is fixed.
|
|
bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
|
|
if (LongSize != 32) return false;
|
|
CallInst *CI = dyn_cast<CallInst>(I);
|
|
if (!CI || !CI->isInlineAsm()) return false;
|
|
if (CI->getNumArgOperands() <= 5) return false;
|
|
// We have inline assembly with quite a few arguments.
|
|
return true;
|
|
}
|
|
|
|
void FunctionStackPoisoner::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
for (int i = 0; i <= kMaxAsanStackMallocSizeClass; i++) {
|
|
std::string Suffix = itostr(i);
|
|
AsanStackMallocFunc[i] = M.getOrInsertFunction(
|
|
kAsanStackMallocNameTemplate + Suffix, IntptrTy, IntptrTy);
|
|
AsanStackFreeFunc[i] =
|
|
M.getOrInsertFunction(kAsanStackFreeNameTemplate + Suffix,
|
|
IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
}
|
|
if (ASan.UseAfterScope) {
|
|
AsanPoisonStackMemoryFunc = M.getOrInsertFunction(
|
|
kAsanPoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
AsanUnpoisonStackMemoryFunc = M.getOrInsertFunction(
|
|
kAsanUnpoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
}
|
|
|
|
for (size_t Val : {0x00, 0xf1, 0xf2, 0xf3, 0xf5, 0xf8}) {
|
|
std::ostringstream Name;
|
|
Name << kAsanSetShadowPrefix;
|
|
Name << std::setw(2) << std::setfill('0') << std::hex << Val;
|
|
AsanSetShadowFunc[Val] =
|
|
M.getOrInsertFunction(Name.str(), IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
}
|
|
|
|
AsanAllocaPoisonFunc = M.getOrInsertFunction(
|
|
kAsanAllocaPoison, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
AsanAllocasUnpoisonFunc = M.getOrInsertFunction(
|
|
kAsanAllocasUnpoison, IRB.getVoidTy(), IntptrTy, IntptrTy);
|
|
}
|
|
|
|
void FunctionStackPoisoner::copyToShadowInline(ArrayRef<uint8_t> ShadowMask,
|
|
ArrayRef<uint8_t> ShadowBytes,
|
|
size_t Begin, size_t End,
|
|
IRBuilder<> &IRB,
|
|
Value *ShadowBase) {
|
|
if (Begin >= End)
|
|
return;
|
|
|
|
const size_t LargestStoreSizeInBytes =
|
|
std::min<size_t>(sizeof(uint64_t), ASan.LongSize / 8);
|
|
|
|
const bool IsLittleEndian = F.getParent()->getDataLayout().isLittleEndian();
|
|
|
|
// Poison given range in shadow using larges store size with out leading and
|
|
// trailing zeros in ShadowMask. Zeros never change, so they need neither
|
|
// poisoning nor up-poisoning. Still we don't mind if some of them get into a
|
|
// middle of a store.
|
|
for (size_t i = Begin; i < End;) {
|
|
if (!ShadowMask[i]) {
|
|
assert(!ShadowBytes[i]);
|
|
++i;
|
|
continue;
|
|
}
|
|
|
|
size_t StoreSizeInBytes = LargestStoreSizeInBytes;
|
|
// Fit store size into the range.
|
|
while (StoreSizeInBytes > End - i)
|
|
StoreSizeInBytes /= 2;
|
|
|
|
// Minimize store size by trimming trailing zeros.
|
|
for (size_t j = StoreSizeInBytes - 1; j && !ShadowMask[i + j]; --j) {
|
|
while (j <= StoreSizeInBytes / 2)
|
|
StoreSizeInBytes /= 2;
|
|
}
|
|
|
|
uint64_t Val = 0;
|
|
for (size_t j = 0; j < StoreSizeInBytes; j++) {
|
|
if (IsLittleEndian)
|
|
Val |= (uint64_t)ShadowBytes[i + j] << (8 * j);
|
|
else
|
|
Val = (Val << 8) | ShadowBytes[i + j];
|
|
}
|
|
|
|
Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
|
|
Value *Poison = IRB.getIntN(StoreSizeInBytes * 8, Val);
|
|
IRB.CreateAlignedStore(
|
|
Poison, IRB.CreateIntToPtr(Ptr, Poison->getType()->getPointerTo()), 1);
|
|
|
|
i += StoreSizeInBytes;
|
|
}
|
|
}
|
|
|
|
void FunctionStackPoisoner::copyToShadow(ArrayRef<uint8_t> ShadowMask,
|
|
ArrayRef<uint8_t> ShadowBytes,
|
|
IRBuilder<> &IRB, Value *ShadowBase) {
|
|
copyToShadow(ShadowMask, ShadowBytes, 0, ShadowMask.size(), IRB, ShadowBase);
|
|
}
|
|
|
|
void FunctionStackPoisoner::copyToShadow(ArrayRef<uint8_t> ShadowMask,
|
|
ArrayRef<uint8_t> ShadowBytes,
|
|
size_t Begin, size_t End,
|
|
IRBuilder<> &IRB, Value *ShadowBase) {
|
|
assert(ShadowMask.size() == ShadowBytes.size());
|
|
size_t Done = Begin;
|
|
for (size_t i = Begin, j = Begin + 1; i < End; i = j++) {
|
|
if (!ShadowMask[i]) {
|
|
assert(!ShadowBytes[i]);
|
|
continue;
|
|
}
|
|
uint8_t Val = ShadowBytes[i];
|
|
if (!AsanSetShadowFunc[Val])
|
|
continue;
|
|
|
|
// Skip same values.
|
|
for (; j < End && ShadowMask[j] && Val == ShadowBytes[j]; ++j) {
|
|
}
|
|
|
|
if (j - i >= ClMaxInlinePoisoningSize) {
|
|
copyToShadowInline(ShadowMask, ShadowBytes, Done, i, IRB, ShadowBase);
|
|
IRB.CreateCall(AsanSetShadowFunc[Val],
|
|
{IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i)),
|
|
ConstantInt::get(IntptrTy, j - i)});
|
|
Done = j;
|
|
}
|
|
}
|
|
|
|
copyToShadowInline(ShadowMask, ShadowBytes, Done, End, IRB, ShadowBase);
|
|
}
|
|
|
|
// Fake stack allocator (asan_fake_stack.h) has 11 size classes
|
|
// for every power of 2 from kMinStackMallocSize to kMaxAsanStackMallocSizeClass
|
|
static int StackMallocSizeClass(uint64_t LocalStackSize) {
|
|
assert(LocalStackSize <= kMaxStackMallocSize);
|
|
uint64_t MaxSize = kMinStackMallocSize;
|
|
for (int i = 0;; i++, MaxSize *= 2)
|
|
if (LocalStackSize <= MaxSize) return i;
|
|
llvm_unreachable("impossible LocalStackSize");
|
|
}
|
|
|
|
void FunctionStackPoisoner::copyArgsPassedByValToAllocas() {
|
|
Instruction *CopyInsertPoint = &F.front().front();
|
|
if (CopyInsertPoint == ASan.LocalDynamicShadow) {
|
|
// Insert after the dynamic shadow location is determined
|
|
CopyInsertPoint = CopyInsertPoint->getNextNode();
|
|
assert(CopyInsertPoint);
|
|
}
|
|
IRBuilder<> IRB(CopyInsertPoint);
|
|
const DataLayout &DL = F.getParent()->getDataLayout();
|
|
for (Argument &Arg : F.args()) {
|
|
if (Arg.hasByValAttr()) {
|
|
Type *Ty = Arg.getType()->getPointerElementType();
|
|
const Align Alignment =
|
|
DL.getValueOrABITypeAlignment(Arg.getParamAlign(), Ty);
|
|
|
|
AllocaInst *AI = IRB.CreateAlloca(
|
|
Ty, nullptr,
|
|
(Arg.hasName() ? Arg.getName() : "Arg" + Twine(Arg.getArgNo())) +
|
|
".byval");
|
|
AI->setAlignment(Alignment);
|
|
Arg.replaceAllUsesWith(AI);
|
|
|
|
uint64_t AllocSize = DL.getTypeAllocSize(Ty);
|
|
IRB.CreateMemCpy(AI, Alignment, &Arg, Alignment, AllocSize);
|
|
}
|
|
}
|
|
}
|
|
|
|
PHINode *FunctionStackPoisoner::createPHI(IRBuilder<> &IRB, Value *Cond,
|
|
Value *ValueIfTrue,
|
|
Instruction *ThenTerm,
|
|
Value *ValueIfFalse) {
|
|
PHINode *PHI = IRB.CreatePHI(IntptrTy, 2);
|
|
BasicBlock *CondBlock = cast<Instruction>(Cond)->getParent();
|
|
PHI->addIncoming(ValueIfFalse, CondBlock);
|
|
BasicBlock *ThenBlock = ThenTerm->getParent();
|
|
PHI->addIncoming(ValueIfTrue, ThenBlock);
|
|
return PHI;
|
|
}
|
|
|
|
Value *FunctionStackPoisoner::createAllocaForLayout(
|
|
IRBuilder<> &IRB, const ASanStackFrameLayout &L, bool Dynamic) {
|
|
AllocaInst *Alloca;
|
|
if (Dynamic) {
|
|
Alloca = IRB.CreateAlloca(IRB.getInt8Ty(),
|
|
ConstantInt::get(IRB.getInt64Ty(), L.FrameSize),
|
|
"MyAlloca");
|
|
} else {
|
|
Alloca = IRB.CreateAlloca(ArrayType::get(IRB.getInt8Ty(), L.FrameSize),
|
|
nullptr, "MyAlloca");
|
|
assert(Alloca->isStaticAlloca());
|
|
}
|
|
assert((ClRealignStack & (ClRealignStack - 1)) == 0);
|
|
size_t FrameAlignment = std::max(L.FrameAlignment, (size_t)ClRealignStack);
|
|
Alloca->setAlignment(MaybeAlign(FrameAlignment));
|
|
return IRB.CreatePointerCast(Alloca, IntptrTy);
|
|
}
|
|
|
|
void FunctionStackPoisoner::createDynamicAllocasInitStorage() {
|
|
BasicBlock &FirstBB = *F.begin();
|
|
IRBuilder<> IRB(dyn_cast<Instruction>(FirstBB.begin()));
|
|
DynamicAllocaLayout = IRB.CreateAlloca(IntptrTy, nullptr);
|
|
IRB.CreateStore(Constant::getNullValue(IntptrTy), DynamicAllocaLayout);
|
|
DynamicAllocaLayout->setAlignment(Align(32));
|
|
}
|
|
|
|
void FunctionStackPoisoner::processDynamicAllocas() {
|
|
if (!ClInstrumentDynamicAllocas || DynamicAllocaVec.empty()) {
|
|
assert(DynamicAllocaPoisonCallVec.empty());
|
|
return;
|
|
}
|
|
|
|
// Insert poison calls for lifetime intrinsics for dynamic allocas.
|
|
for (const auto &APC : DynamicAllocaPoisonCallVec) {
|
|
assert(APC.InsBefore);
|
|
assert(APC.AI);
|
|
assert(ASan.isInterestingAlloca(*APC.AI));
|
|
assert(!APC.AI->isStaticAlloca());
|
|
|
|
IRBuilder<> IRB(APC.InsBefore);
|
|
poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison);
|
|
// Dynamic allocas will be unpoisoned unconditionally below in
|
|
// unpoisonDynamicAllocas.
|
|
// Flag that we need unpoison static allocas.
|
|
}
|
|
|
|
// Handle dynamic allocas.
|
|
createDynamicAllocasInitStorage();
|
|
for (auto &AI : DynamicAllocaVec)
|
|
handleDynamicAllocaCall(AI);
|
|
unpoisonDynamicAllocas();
|
|
}
|
|
|
|
void FunctionStackPoisoner::processStaticAllocas() {
|
|
if (AllocaVec.empty()) {
|
|
assert(StaticAllocaPoisonCallVec.empty());
|
|
return;
|
|
}
|
|
|
|
int StackMallocIdx = -1;
|
|
DebugLoc EntryDebugLocation;
|
|
if (auto SP = F.getSubprogram())
|
|
EntryDebugLocation = DebugLoc::get(SP->getScopeLine(), 0, SP);
|
|
|
|
Instruction *InsBefore = AllocaVec[0];
|
|
IRBuilder<> IRB(InsBefore);
|
|
|
|
// Make sure non-instrumented allocas stay in the entry block. Otherwise,
|
|
// debug info is broken, because only entry-block allocas are treated as
|
|
// regular stack slots.
|
|
auto InsBeforeB = InsBefore->getParent();
|
|
assert(InsBeforeB == &F.getEntryBlock());
|
|
for (auto *AI : StaticAllocasToMoveUp)
|
|
if (AI->getParent() == InsBeforeB)
|
|
AI->moveBefore(InsBefore);
|
|
|
|
// If we have a call to llvm.localescape, keep it in the entry block.
|
|
if (LocalEscapeCall) LocalEscapeCall->moveBefore(InsBefore);
|
|
|
|
SmallVector<ASanStackVariableDescription, 16> SVD;
|
|
SVD.reserve(AllocaVec.size());
|
|
for (AllocaInst *AI : AllocaVec) {
|
|
ASanStackVariableDescription D = {AI->getName().data(),
|
|
ASan.getAllocaSizeInBytes(*AI),
|
|
0,
|
|
AI->getAlignment(),
|
|
AI,
|
|
0,
|
|
0};
|
|
SVD.push_back(D);
|
|
}
|
|
|
|
// Minimal header size (left redzone) is 4 pointers,
|
|
// i.e. 32 bytes on 64-bit platforms and 16 bytes in 32-bit platforms.
|
|
size_t Granularity = 1ULL << Mapping.Scale;
|
|
size_t MinHeaderSize = std::max((size_t)ASan.LongSize / 2, Granularity);
|
|
const ASanStackFrameLayout &L =
|
|
ComputeASanStackFrameLayout(SVD, Granularity, MinHeaderSize);
|
|
|
|
// Build AllocaToSVDMap for ASanStackVariableDescription lookup.
|
|
DenseMap<const AllocaInst *, ASanStackVariableDescription *> AllocaToSVDMap;
|
|
for (auto &Desc : SVD)
|
|
AllocaToSVDMap[Desc.AI] = &Desc;
|
|
|
|
// Update SVD with information from lifetime intrinsics.
|
|
for (const auto &APC : StaticAllocaPoisonCallVec) {
|
|
assert(APC.InsBefore);
|
|
assert(APC.AI);
|
|
assert(ASan.isInterestingAlloca(*APC.AI));
|
|
assert(APC.AI->isStaticAlloca());
|
|
|
|
ASanStackVariableDescription &Desc = *AllocaToSVDMap[APC.AI];
|
|
Desc.LifetimeSize = Desc.Size;
|
|
if (const DILocation *FnLoc = EntryDebugLocation.get()) {
|
|
if (const DILocation *LifetimeLoc = APC.InsBefore->getDebugLoc().get()) {
|
|
if (LifetimeLoc->getFile() == FnLoc->getFile())
|
|
if (unsigned Line = LifetimeLoc->getLine())
|
|
Desc.Line = std::min(Desc.Line ? Desc.Line : Line, Line);
|
|
}
|
|
}
|
|
}
|
|
|
|
auto DescriptionString = ComputeASanStackFrameDescription(SVD);
|
|
LLVM_DEBUG(dbgs() << DescriptionString << " --- " << L.FrameSize << "\n");
|
|
uint64_t LocalStackSize = L.FrameSize;
|
|
bool DoStackMalloc = ClUseAfterReturn && !ASan.CompileKernel &&
|
|
LocalStackSize <= kMaxStackMallocSize;
|
|
bool DoDynamicAlloca = ClDynamicAllocaStack;
|
|
// Don't do dynamic alloca or stack malloc if:
|
|
// 1) There is inline asm: too often it makes assumptions on which registers
|
|
// are available.
|
|
// 2) There is a returns_twice call (typically setjmp), which is
|
|
// optimization-hostile, and doesn't play well with introduced indirect
|
|
// register-relative calculation of local variable addresses.
|
|
DoDynamicAlloca &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
|
|
DoStackMalloc &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
|
|
|
|
Value *StaticAlloca =
|
|
DoDynamicAlloca ? nullptr : createAllocaForLayout(IRB, L, false);
|
|
|
|
Value *FakeStack;
|
|
Value *LocalStackBase;
|
|
Value *LocalStackBaseAlloca;
|
|
uint8_t DIExprFlags = DIExpression::ApplyOffset;
|
|
|
|
if (DoStackMalloc) {
|
|
LocalStackBaseAlloca =
|
|
IRB.CreateAlloca(IntptrTy, nullptr, "asan_local_stack_base");
|
|
// void *FakeStack = __asan_option_detect_stack_use_after_return
|
|
// ? __asan_stack_malloc_N(LocalStackSize)
|
|
// : nullptr;
|
|
// void *LocalStackBase = (FakeStack) ? FakeStack : alloca(LocalStackSize);
|
|
Constant *OptionDetectUseAfterReturn = F.getParent()->getOrInsertGlobal(
|
|
kAsanOptionDetectUseAfterReturn, IRB.getInt32Ty());
|
|
Value *UseAfterReturnIsEnabled = IRB.CreateICmpNE(
|
|
IRB.CreateLoad(IRB.getInt32Ty(), OptionDetectUseAfterReturn),
|
|
Constant::getNullValue(IRB.getInt32Ty()));
|
|
Instruction *Term =
|
|
SplitBlockAndInsertIfThen(UseAfterReturnIsEnabled, InsBefore, false);
|
|
IRBuilder<> IRBIf(Term);
|
|
StackMallocIdx = StackMallocSizeClass(LocalStackSize);
|
|
assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
|
|
Value *FakeStackValue =
|
|
IRBIf.CreateCall(AsanStackMallocFunc[StackMallocIdx],
|
|
ConstantInt::get(IntptrTy, LocalStackSize));
|
|
IRB.SetInsertPoint(InsBefore);
|
|
FakeStack = createPHI(IRB, UseAfterReturnIsEnabled, FakeStackValue, Term,
|
|
ConstantInt::get(IntptrTy, 0));
|
|
|
|
Value *NoFakeStack =
|
|
IRB.CreateICmpEQ(FakeStack, Constant::getNullValue(IntptrTy));
|
|
Term = SplitBlockAndInsertIfThen(NoFakeStack, InsBefore, false);
|
|
IRBIf.SetInsertPoint(Term);
|
|
Value *AllocaValue =
|
|
DoDynamicAlloca ? createAllocaForLayout(IRBIf, L, true) : StaticAlloca;
|
|
|
|
IRB.SetInsertPoint(InsBefore);
|
|
LocalStackBase = createPHI(IRB, NoFakeStack, AllocaValue, Term, FakeStack);
|
|
IRB.CreateStore(LocalStackBase, LocalStackBaseAlloca);
|
|
DIExprFlags |= DIExpression::DerefBefore;
|
|
} else {
|
|
// void *FakeStack = nullptr;
|
|
// void *LocalStackBase = alloca(LocalStackSize);
|
|
FakeStack = ConstantInt::get(IntptrTy, 0);
|
|
LocalStackBase =
|
|
DoDynamicAlloca ? createAllocaForLayout(IRB, L, true) : StaticAlloca;
|
|
LocalStackBaseAlloca = LocalStackBase;
|
|
}
|
|
|
|
// Replace Alloca instructions with base+offset.
|
|
for (const auto &Desc : SVD) {
|
|
AllocaInst *AI = Desc.AI;
|
|
replaceDbgDeclareForAlloca(AI, LocalStackBaseAlloca, DIB, DIExprFlags,
|
|
Desc.Offset);
|
|
Value *NewAllocaPtr = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)),
|
|
AI->getType());
|
|
AI->replaceAllUsesWith(NewAllocaPtr);
|
|
}
|
|
|
|
// The left-most redzone has enough space for at least 4 pointers.
|
|
// Write the Magic value to redzone[0].
|
|
Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
|
|
IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
|
|
BasePlus0);
|
|
// Write the frame description constant to redzone[1].
|
|
Value *BasePlus1 = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase,
|
|
ConstantInt::get(IntptrTy, ASan.LongSize / 8)),
|
|
IntptrPtrTy);
|
|
GlobalVariable *StackDescriptionGlobal =
|
|
createPrivateGlobalForString(*F.getParent(), DescriptionString,
|
|
/*AllowMerging*/ true, kAsanGenPrefix);
|
|
Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
|
|
IRB.CreateStore(Description, BasePlus1);
|
|
// Write the PC to redzone[2].
|
|
Value *BasePlus2 = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase,
|
|
ConstantInt::get(IntptrTy, 2 * ASan.LongSize / 8)),
|
|
IntptrPtrTy);
|
|
IRB.CreateStore(IRB.CreatePointerCast(&F, IntptrTy), BasePlus2);
|
|
|
|
const auto &ShadowAfterScope = GetShadowBytesAfterScope(SVD, L);
|
|
|
|
// Poison the stack red zones at the entry.
|
|
Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB);
|
|
// As mask we must use most poisoned case: red zones and after scope.
|
|
// As bytes we can use either the same or just red zones only.
|
|
copyToShadow(ShadowAfterScope, ShadowAfterScope, IRB, ShadowBase);
|
|
|
|
if (!StaticAllocaPoisonCallVec.empty()) {
|
|
const auto &ShadowInScope = GetShadowBytes(SVD, L);
|
|
|
|
// Poison static allocas near lifetime intrinsics.
|
|
for (const auto &APC : StaticAllocaPoisonCallVec) {
|
|
const ASanStackVariableDescription &Desc = *AllocaToSVDMap[APC.AI];
|
|
assert(Desc.Offset % L.Granularity == 0);
|
|
size_t Begin = Desc.Offset / L.Granularity;
|
|
size_t End = Begin + (APC.Size + L.Granularity - 1) / L.Granularity;
|
|
|
|
IRBuilder<> IRB(APC.InsBefore);
|
|
copyToShadow(ShadowAfterScope,
|
|
APC.DoPoison ? ShadowAfterScope : ShadowInScope, Begin, End,
|
|
IRB, ShadowBase);
|
|
}
|
|
}
|
|
|
|
SmallVector<uint8_t, 64> ShadowClean(ShadowAfterScope.size(), 0);
|
|
SmallVector<uint8_t, 64> ShadowAfterReturn;
|
|
|
|
// (Un)poison the stack before all ret instructions.
|
|
for (auto Ret : RetVec) {
|
|
IRBuilder<> IRBRet(Ret);
|
|
// Mark the current frame as retired.
|
|
IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
|
|
BasePlus0);
|
|
if (DoStackMalloc) {
|
|
assert(StackMallocIdx >= 0);
|
|
// if FakeStack != 0 // LocalStackBase == FakeStack
|
|
// // In use-after-return mode, poison the whole stack frame.
|
|
// if StackMallocIdx <= 4
|
|
// // For small sizes inline the whole thing:
|
|
// memset(ShadowBase, kAsanStackAfterReturnMagic, ShadowSize);
|
|
// **SavedFlagPtr(FakeStack) = 0
|
|
// else
|
|
// __asan_stack_free_N(FakeStack, LocalStackSize)
|
|
// else
|
|
// <This is not a fake stack; unpoison the redzones>
|
|
Value *Cmp =
|
|
IRBRet.CreateICmpNE(FakeStack, Constant::getNullValue(IntptrTy));
|
|
Instruction *ThenTerm, *ElseTerm;
|
|
SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm);
|
|
|
|
IRBuilder<> IRBPoison(ThenTerm);
|
|
if (StackMallocIdx <= 4) {
|
|
int ClassSize = kMinStackMallocSize << StackMallocIdx;
|
|
ShadowAfterReturn.resize(ClassSize / L.Granularity,
|
|
kAsanStackUseAfterReturnMagic);
|
|
copyToShadow(ShadowAfterReturn, ShadowAfterReturn, IRBPoison,
|
|
ShadowBase);
|
|
Value *SavedFlagPtrPtr = IRBPoison.CreateAdd(
|
|
FakeStack,
|
|
ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8));
|
|
Value *SavedFlagPtr = IRBPoison.CreateLoad(
|
|
IntptrTy, IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy));
|
|
IRBPoison.CreateStore(
|
|
Constant::getNullValue(IRBPoison.getInt8Ty()),
|
|
IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy()));
|
|
} else {
|
|
// For larger frames call __asan_stack_free_*.
|
|
IRBPoison.CreateCall(
|
|
AsanStackFreeFunc[StackMallocIdx],
|
|
{FakeStack, ConstantInt::get(IntptrTy, LocalStackSize)});
|
|
}
|
|
|
|
IRBuilder<> IRBElse(ElseTerm);
|
|
copyToShadow(ShadowAfterScope, ShadowClean, IRBElse, ShadowBase);
|
|
} else {
|
|
copyToShadow(ShadowAfterScope, ShadowClean, IRBRet, ShadowBase);
|
|
}
|
|
}
|
|
|
|
// We are done. Remove the old unused alloca instructions.
|
|
for (auto AI : AllocaVec) AI->eraseFromParent();
|
|
}
|
|
|
|
void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size,
|
|
IRBuilder<> &IRB, bool DoPoison) {
|
|
// For now just insert the call to ASan runtime.
|
|
Value *AddrArg = IRB.CreatePointerCast(V, IntptrTy);
|
|
Value *SizeArg = ConstantInt::get(IntptrTy, Size);
|
|
IRB.CreateCall(
|
|
DoPoison ? AsanPoisonStackMemoryFunc : AsanUnpoisonStackMemoryFunc,
|
|
{AddrArg, SizeArg});
|
|
}
|
|
|
|
// Handling llvm.lifetime intrinsics for a given %alloca:
|
|
// (1) collect all llvm.lifetime.xxx(%size, %value) describing the alloca.
|
|
// (2) if %size is constant, poison memory for llvm.lifetime.end (to detect
|
|
// invalid accesses) and unpoison it for llvm.lifetime.start (the memory
|
|
// could be poisoned by previous llvm.lifetime.end instruction, as the
|
|
// variable may go in and out of scope several times, e.g. in loops).
|
|
// (3) if we poisoned at least one %alloca in a function,
|
|
// unpoison the whole stack frame at function exit.
|
|
void FunctionStackPoisoner::handleDynamicAllocaCall(AllocaInst *AI) {
|
|
IRBuilder<> IRB(AI);
|
|
|
|
const unsigned Align = std::max(kAllocaRzSize, AI->getAlignment());
|
|
const uint64_t AllocaRedzoneMask = kAllocaRzSize - 1;
|
|
|
|
Value *Zero = Constant::getNullValue(IntptrTy);
|
|
Value *AllocaRzSize = ConstantInt::get(IntptrTy, kAllocaRzSize);
|
|
Value *AllocaRzMask = ConstantInt::get(IntptrTy, AllocaRedzoneMask);
|
|
|
|
// Since we need to extend alloca with additional memory to locate
|
|
// redzones, and OldSize is number of allocated blocks with
|
|
// ElementSize size, get allocated memory size in bytes by
|
|
// OldSize * ElementSize.
|
|
const unsigned ElementSize =
|
|
F.getParent()->getDataLayout().getTypeAllocSize(AI->getAllocatedType());
|
|
Value *OldSize =
|
|
IRB.CreateMul(IRB.CreateIntCast(AI->getArraySize(), IntptrTy, false),
|
|
ConstantInt::get(IntptrTy, ElementSize));
|
|
|
|
// PartialSize = OldSize % 32
|
|
Value *PartialSize = IRB.CreateAnd(OldSize, AllocaRzMask);
|
|
|
|
// Misalign = kAllocaRzSize - PartialSize;
|
|
Value *Misalign = IRB.CreateSub(AllocaRzSize, PartialSize);
|
|
|
|
// PartialPadding = Misalign != kAllocaRzSize ? Misalign : 0;
|
|
Value *Cond = IRB.CreateICmpNE(Misalign, AllocaRzSize);
|
|
Value *PartialPadding = IRB.CreateSelect(Cond, Misalign, Zero);
|
|
|
|
// AdditionalChunkSize = Align + PartialPadding + kAllocaRzSize
|
|
// Align is added to locate left redzone, PartialPadding for possible
|
|
// partial redzone and kAllocaRzSize for right redzone respectively.
|
|
Value *AdditionalChunkSize = IRB.CreateAdd(
|
|
ConstantInt::get(IntptrTy, Align + kAllocaRzSize), PartialPadding);
|
|
|
|
Value *NewSize = IRB.CreateAdd(OldSize, AdditionalChunkSize);
|
|
|
|
// Insert new alloca with new NewSize and Align params.
|
|
AllocaInst *NewAlloca = IRB.CreateAlloca(IRB.getInt8Ty(), NewSize);
|
|
NewAlloca->setAlignment(MaybeAlign(Align));
|
|
|
|
// NewAddress = Address + Align
|
|
Value *NewAddress = IRB.CreateAdd(IRB.CreatePtrToInt(NewAlloca, IntptrTy),
|
|
ConstantInt::get(IntptrTy, Align));
|
|
|
|
// Insert __asan_alloca_poison call for new created alloca.
|
|
IRB.CreateCall(AsanAllocaPoisonFunc, {NewAddress, OldSize});
|
|
|
|
// Store the last alloca's address to DynamicAllocaLayout. We'll need this
|
|
// for unpoisoning stuff.
|
|
IRB.CreateStore(IRB.CreatePtrToInt(NewAlloca, IntptrTy), DynamicAllocaLayout);
|
|
|
|
Value *NewAddressPtr = IRB.CreateIntToPtr(NewAddress, AI->getType());
|
|
|
|
// Replace all uses of AddessReturnedByAlloca with NewAddressPtr.
|
|
AI->replaceAllUsesWith(NewAddressPtr);
|
|
|
|
// We are done. Erase old alloca from parent.
|
|
AI->eraseFromParent();
|
|
}
|
|
|
|
// isSafeAccess returns true if Addr is always inbounds with respect to its
|
|
// base object. For example, it is a field access or an array access with
|
|
// constant inbounds index.
|
|
bool AddressSanitizer::isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis,
|
|
Value *Addr, uint64_t TypeSize) const {
|
|
SizeOffsetType SizeOffset = ObjSizeVis.compute(Addr);
|
|
if (!ObjSizeVis.bothKnown(SizeOffset)) return false;
|
|
uint64_t Size = SizeOffset.first.getZExtValue();
|
|
int64_t Offset = SizeOffset.second.getSExtValue();
|
|
// Three checks are required to ensure safety:
|
|
// . Offset >= 0 (since the offset is given from the base ptr)
|
|
// . Size >= Offset (unsigned)
|
|
// . Size - Offset >= NeededSize (unsigned)
|
|
return Offset >= 0 && Size >= uint64_t(Offset) &&
|
|
Size - uint64_t(Offset) >= TypeSize / 8;
|
|
}
|