mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-26 07:29:55 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216972 91177308-0d34-0410-b5e6-96231b3b80d8
1813 lines
72 KiB
C++
1813 lines
72 KiB
C++
//===-- AddressSanitizer.cpp - memory error detector ------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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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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// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Instrumentation.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/DenseSet.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/SmallString.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/Triple.h"
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#include "llvm/IR/CallSite.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/Function.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/IntrinsicInst.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/Module.h"
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#include "llvm/IR/Type.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/DataTypes.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/Endian.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/Cloning.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 <algorithm>
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#include <string>
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#include <system_error>
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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 kIOSShadowOffset32 = 1ULL << 30;
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static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
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static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000; // < 2G.
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static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
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static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa8000;
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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 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 int kAsanCtorAndDtorPriority = 1;
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static const char *const kAsanReportErrorTemplate = "__asan_report_";
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static const char *const kAsanReportLoadN = "__asan_report_load_n";
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static const char *const kAsanReportStoreN = "__asan_report_store_n";
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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 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_v4";
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static const char *const kAsanCovModuleInitName = "__sanitizer_cov_module_init";
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static const char *const kAsanCovName = "__sanitizer_cov";
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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 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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static const char *const kAsanOptionDetectUAR =
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"__asan_option_detect_stack_use_after_return";
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#ifndef NDEBUG
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static const int kAsanStackAfterReturnMagic = 0xf5;
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#endif
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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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// Command-line flags.
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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"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInstrumentWrites("asan-instrument-writes",
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cl::desc("instrument write instructions"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInstrumentAtomics("asan-instrument-atomics",
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cl::desc("instrument atomic instructions (rmw, cmpxchg)"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClAlwaysSlowPath("asan-always-slow-path",
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cl::desc("use instrumentation with slow path for all accesses"),
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cl::Hidden, cl::init(false));
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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("asan-max-ins-per-bb",
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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",
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cl::desc("Handle stack memory"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
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cl::desc("Check return-after-free"), cl::Hidden, cl::init(true));
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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, cl::init(true));
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static cl::opt<int> ClCoverage("asan-coverage",
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cl::desc("ASan coverage. 0: none, 1: entry block, 2: all blocks"),
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cl::Hidden, cl::init(false));
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static cl::opt<int> ClCoverageBlockThreshold("asan-coverage-block-threshold",
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cl::desc("Add coverage instrumentation only to the entry block if there "
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"are more than this number of blocks."),
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cl::Hidden, cl::init(1500));
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static cl::opt<bool> ClInitializers("asan-initialization-order",
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cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInvalidPointerPairs("asan-detect-invalid-pointer-pair",
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cl::desc("Instrument <, <=, >, >=, - with pointer operands"),
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cl::Hidden, cl::init(false));
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static cl::opt<unsigned> ClRealignStack("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("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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// This is an experimental feature that will allow to choose between
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// instrumented and non-instrumented code at link-time.
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// If this option is on, just before instrumenting a function we create its
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// clone; if the function is not changed by asan the clone is deleted.
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// If we end up with a clone, we put the instrumented function into a section
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// called "ASAN" and the uninstrumented function into a section called "NOASAN".
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//
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// This is still a prototype, we need to figure out a way to keep two copies of
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// a function so that the linker can easily choose one of them.
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static cl::opt<bool> ClKeepUninstrumented("asan-keep-uninstrumented-functions",
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cl::desc("Keep uninstrumented copies of functions"),
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cl::Hidden, cl::init(false));
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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) + (1 << offset_log)
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static cl::opt<int> ClMappingScale("asan-mapping-scale",
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cl::desc("scale of asan shadow mapping"), 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",
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cl::desc("Optimize instrumentation"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClOptSameTemp("asan-opt-same-temp",
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cl::desc("Instrument the same temp just once"), cl::Hidden,
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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"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClCheckLifetime("asan-check-lifetime",
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cl::desc("Use llvm.lifetime intrinsics to insert extra checks"),
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cl::Hidden, cl::init(false));
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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",
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cl::Hidden, 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 man 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(NumOptimizedAccessesToGlobalArray,
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"Number of optimized accesses to global arrays");
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STATISTIC(NumOptimizedAccessesToGlobalVar,
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"Number of optimized accesses to global vars");
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namespace {
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/// Frontend-provided metadata for source location.
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struct LocationMetadata {
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StringRef Filename;
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int LineNo;
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int ColumnNo;
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LocationMetadata() : Filename(), LineNo(0), ColumnNo(0) {}
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bool empty() const { return Filename.empty(); }
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void parse(MDNode *MDN) {
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assert(MDN->getNumOperands() == 3);
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MDString *MDFilename = cast<MDString>(MDN->getOperand(0));
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Filename = MDFilename->getString();
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LineNo = cast<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
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ColumnNo = cast<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
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}
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};
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/// Frontend-provided metadata for global variables.
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class GlobalsMetadata {
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public:
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struct Entry {
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Entry()
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: SourceLoc(), Name(), IsDynInit(false),
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IsBlacklisted(false) {}
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LocationMetadata SourceLoc;
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StringRef Name;
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bool IsDynInit;
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bool IsBlacklisted;
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};
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GlobalsMetadata() : inited_(false) {}
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void init(Module& M) {
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assert(!inited_);
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inited_ = true;
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NamedMDNode *Globals = M.getNamedMetadata("llvm.asan.globals");
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if (!Globals)
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return;
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for (auto MDN : Globals->operands()) {
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// Metadata node contains the global and the fields of "Entry".
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assert(MDN->getNumOperands() == 5);
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Value *V = MDN->getOperand(0);
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// The optimizer may optimize away a global entirely.
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if (!V)
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continue;
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GlobalVariable *GV = cast<GlobalVariable>(V);
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// We can already have an entry for GV if it was merged with another
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// global.
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Entry &E = Entries[GV];
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if (Value *Loc = MDN->getOperand(1))
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E.SourceLoc.parse(cast<MDNode>(Loc));
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if (Value *Name = MDN->getOperand(2)) {
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MDString *MDName = cast<MDString>(Name);
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E.Name = MDName->getString();
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}
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ConstantInt *IsDynInit = cast<ConstantInt>(MDN->getOperand(3));
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E.IsDynInit |= IsDynInit->isOne();
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ConstantInt *IsBlacklisted = cast<ConstantInt>(MDN->getOperand(4));
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E.IsBlacklisted |= IsBlacklisted->isOne();
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}
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}
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/// Returns metadata entry for a given global.
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Entry get(GlobalVariable *G) const {
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auto Pos = Entries.find(G);
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return (Pos != Entries.end()) ? Pos->second : Entry();
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}
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private:
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bool inited_;
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DenseMap<GlobalVariable*, Entry> Entries;
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};
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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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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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};
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static ShadowMapping getShadowMapping(const Module &M, int LongSize) {
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llvm::Triple TargetTriple(M.getTargetTriple());
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bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
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bool IsIOS = TargetTriple.getOS() == llvm::Triple::IOS;
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bool IsFreeBSD = TargetTriple.getOS() == llvm::Triple::FreeBSD;
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bool IsLinux = TargetTriple.getOS() == llvm::Triple::Linux;
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bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 ||
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TargetTriple.getArch() == llvm::Triple::ppc64le;
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bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
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bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips ||
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TargetTriple.getArch() == llvm::Triple::mipsel;
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ShadowMapping Mapping;
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if (LongSize == 32) {
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if (IsAndroid)
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Mapping.Offset = 0;
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else if (IsMIPS32)
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Mapping.Offset = kMIPS32_ShadowOffset32;
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else if (IsFreeBSD)
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Mapping.Offset = kFreeBSD_ShadowOffset32;
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else if (IsIOS)
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Mapping.Offset = kIOSShadowOffset32;
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else
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Mapping.Offset = kDefaultShadowOffset32;
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} else { // LongSize == 64
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if (IsPPC64)
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Mapping.Offset = kPPC64_ShadowOffset64;
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else if (IsFreeBSD)
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Mapping.Offset = kFreeBSD_ShadowOffset64;
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else if (IsLinux && IsX86_64)
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Mapping.Offset = kSmallX86_64ShadowOffset;
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else
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Mapping.Offset = kDefaultShadowOffset64;
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}
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Mapping.Scale = kDefaultShadowScale;
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if (ClMappingScale) {
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Mapping.Scale = ClMappingScale;
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}
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// OR-ing shadow offset if more efficient (at least on x86) if the offset
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// is a power of two, but on ppc64 we have to use add since the shadow
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// offset is not necessary 1/8-th of the address space.
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Mapping.OrShadowOffset = !IsPPC64 && !(Mapping.Offset & (Mapping.Offset - 1));
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return Mapping;
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}
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static size_t RedzoneSizeForScale(int MappingScale) {
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// Redzone used for stack and globals is at least 32 bytes.
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// For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
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return std::max(32U, 1U << MappingScale);
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}
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/// AddressSanitizer: instrument the code in module to find memory bugs.
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struct AddressSanitizer : public FunctionPass {
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AddressSanitizer() : FunctionPass(ID) {}
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const char *getPassName() const override {
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return "AddressSanitizerFunctionPass";
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}
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void instrumentMop(Instruction *I, bool UseCalls);
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void instrumentPointerComparisonOrSubtraction(Instruction *I);
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void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
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Value *Addr, uint32_t TypeSize, bool IsWrite,
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Value *SizeArgument, bool UseCalls);
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Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
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Value *ShadowValue, uint32_t TypeSize);
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Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
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bool IsWrite, size_t AccessSizeIndex,
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Value *SizeArgument);
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void instrumentMemIntrinsic(MemIntrinsic *MI);
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Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
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bool runOnFunction(Function &F) override;
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bool maybeInsertAsanInitAtFunctionEntry(Function &F);
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bool doInitialization(Module &M) override;
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static char ID; // Pass identification, replacement for typeid
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private:
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void initializeCallbacks(Module &M);
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bool LooksLikeCodeInBug11395(Instruction *I);
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bool GlobalIsLinkerInitialized(GlobalVariable *G);
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bool InjectCoverage(Function &F, ArrayRef<BasicBlock*> AllBlocks);
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void InjectCoverageAtBlock(Function &F, BasicBlock &BB);
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LLVMContext *C;
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const DataLayout *DL;
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int LongSize;
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Type *IntptrTy;
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ShadowMapping Mapping;
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Function *AsanCtorFunction;
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Function *AsanInitFunction;
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Function *AsanHandleNoReturnFunc;
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Function *AsanCovFunction;
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Function *AsanPtrCmpFunction, *AsanPtrSubFunction;
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// This array is indexed by AccessIsWrite and log2(AccessSize).
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Function *AsanErrorCallback[2][kNumberOfAccessSizes];
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Function *AsanMemoryAccessCallback[2][kNumberOfAccessSizes];
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// This array is indexed by AccessIsWrite.
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Function *AsanErrorCallbackSized[2],
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*AsanMemoryAccessCallbackSized[2];
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Function *AsanMemmove, *AsanMemcpy, *AsanMemset;
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InlineAsm *EmptyAsm;
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GlobalsMetadata GlobalsMD;
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friend struct FunctionStackPoisoner;
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};
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class AddressSanitizerModule : public ModulePass {
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public:
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AddressSanitizerModule() : ModulePass(ID) {}
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bool runOnModule(Module &M) override;
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static char ID; // Pass identification, replacement for typeid
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const char *getPassName() const override {
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return "AddressSanitizerModule";
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}
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private:
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void initializeCallbacks(Module &M);
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|
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bool InstrumentGlobals(IRBuilder<> &IRB, Module &M);
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bool ShouldInstrumentGlobal(GlobalVariable *G);
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void poisonOneInitializer(Function &GlobalInit, GlobalValue *ModuleName);
|
|
void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName);
|
|
size_t MinRedzoneSizeForGlobal() const {
|
|
return RedzoneSizeForScale(Mapping.Scale);
|
|
}
|
|
|
|
GlobalsMetadata GlobalsMD;
|
|
Type *IntptrTy;
|
|
LLVMContext *C;
|
|
const DataLayout *DL;
|
|
ShadowMapping Mapping;
|
|
Function *AsanPoisonGlobals;
|
|
Function *AsanUnpoisonGlobals;
|
|
Function *AsanRegisterGlobals;
|
|
Function *AsanUnregisterGlobals;
|
|
Function *AsanCovModuleInit;
|
|
};
|
|
|
|
// 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<Instruction*, 8> RetVec;
|
|
unsigned StackAlignment;
|
|
|
|
Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1],
|
|
*AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
|
|
Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc;
|
|
|
|
// 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> AllocaPoisonCallVec;
|
|
|
|
// Maps Value to an AllocaInst from which the Value is originated.
|
|
typedef DenseMap<Value*, AllocaInst*> AllocaForValueMapTy;
|
|
AllocaForValueMapTy AllocaForValue;
|
|
|
|
FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
|
|
: F(F), ASan(ASan), DIB(*F.getParent()), C(ASan.C),
|
|
IntptrTy(ASan.IntptrTy), IntptrPtrTy(PointerType::get(IntptrTy, 0)),
|
|
Mapping(ASan.Mapping),
|
|
StackAlignment(1 << Mapping.Scale) {}
|
|
|
|
bool runOnFunction() {
|
|
if (!ClStack) return false;
|
|
// Collect alloca, ret, lifetime instructions etc.
|
|
for (BasicBlock *BB : depth_first(&F.getEntryBlock()))
|
|
visit(*BB);
|
|
|
|
if (AllocaVec.empty()) return false;
|
|
|
|
initializeCallbacks(*F.getParent());
|
|
|
|
poisonStack();
|
|
|
|
if (ClDebugStack) {
|
|
DEBUG(dbgs() << F);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// Finds all static Alloca instructions and puts
|
|
// poisoned red zones around all of them.
|
|
// Then unpoison everything back before the function returns.
|
|
void poisonStack();
|
|
|
|
// ----------------------- Visitors.
|
|
/// \brief Collect all Ret instructions.
|
|
void visitReturnInst(ReturnInst &RI) {
|
|
RetVec.push_back(&RI);
|
|
}
|
|
|
|
/// \brief Collect Alloca instructions we want (and can) handle.
|
|
void visitAllocaInst(AllocaInst &AI) {
|
|
if (!isInterestingAlloca(AI)) return;
|
|
|
|
StackAlignment = std::max(StackAlignment, AI.getAlignment());
|
|
AllocaVec.push_back(&AI);
|
|
}
|
|
|
|
/// \brief Collect lifetime intrinsic calls to check for use-after-scope
|
|
/// errors.
|
|
void visitIntrinsicInst(IntrinsicInst &II) {
|
|
if (!ClCheckLifetime) return;
|
|
Intrinsic::ID ID = II.getIntrinsicID();
|
|
if (ID != Intrinsic::lifetime_start &&
|
|
ID != Intrinsic::lifetime_end)
|
|
return;
|
|
// Found lifetime intrinsic, add ASan instrumentation if necessary.
|
|
ConstantInt *Size = dyn_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 = findAllocaForValue(II.getArgOperand(1));
|
|
if (!AI) return;
|
|
bool DoPoison = (ID == Intrinsic::lifetime_end);
|
|
AllocaPoisonCall APC = {&II, AI, SizeValue, DoPoison};
|
|
AllocaPoisonCallVec.push_back(APC);
|
|
}
|
|
|
|
// ---------------------- Helpers.
|
|
void initializeCallbacks(Module &M);
|
|
|
|
// Check if we want (and can) handle this alloca.
|
|
bool isInterestingAlloca(AllocaInst &AI) const {
|
|
return (!AI.isArrayAllocation() && AI.isStaticAlloca() &&
|
|
AI.getAllocatedType()->isSized() &&
|
|
// alloca() may be called with 0 size, ignore it.
|
|
getAllocaSizeInBytes(&AI) > 0);
|
|
}
|
|
|
|
uint64_t getAllocaSizeInBytes(AllocaInst *AI) const {
|
|
Type *Ty = AI->getAllocatedType();
|
|
uint64_t SizeInBytes = ASan.DL->getTypeAllocSize(Ty);
|
|
return SizeInBytes;
|
|
}
|
|
/// Finds alloca where the value comes from.
|
|
AllocaInst *findAllocaForValue(Value *V);
|
|
void poisonRedZones(ArrayRef<uint8_t> ShadowBytes, IRBuilder<> &IRB,
|
|
Value *ShadowBase, bool DoPoison);
|
|
void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> &IRB, bool DoPoison);
|
|
|
|
void SetShadowToStackAfterReturnInlined(IRBuilder<> &IRB, Value *ShadowBase,
|
|
int Size);
|
|
};
|
|
|
|
} // namespace
|
|
|
|
char AddressSanitizer::ID = 0;
|
|
INITIALIZE_PASS(AddressSanitizer, "asan",
|
|
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
|
|
false, false)
|
|
FunctionPass *llvm::createAddressSanitizerFunctionPass() {
|
|
return new AddressSanitizer();
|
|
}
|
|
|
|
char AddressSanitizerModule::ID = 0;
|
|
INITIALIZE_PASS(AddressSanitizerModule, "asan-module",
|
|
"AddressSanitizer: detects use-after-free and out-of-bounds bugs."
|
|
"ModulePass", false, false)
|
|
ModulePass *llvm::createAddressSanitizerModulePass() {
|
|
return new AddressSanitizerModule();
|
|
}
|
|
|
|
static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
|
|
size_t Res = countTrailingZeros(TypeSize / 8);
|
|
assert(Res < kNumberOfAccessSizes);
|
|
return Res;
|
|
}
|
|
|
|
// \brief Create a constant for Str so that we can pass it to the run-time lib.
|
|
static GlobalVariable *createPrivateGlobalForString(
|
|
Module &M, StringRef Str, bool AllowMerging) {
|
|
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
|
|
// We use private linkage for module-local strings. If they can be merged
|
|
// with another one, we set the unnamed_addr attribute.
|
|
GlobalVariable *GV =
|
|
new GlobalVariable(M, StrConst->getType(), true,
|
|
GlobalValue::PrivateLinkage, StrConst, kAsanGenPrefix);
|
|
if (AllowMerging)
|
|
GV->setUnnamedAddr(true);
|
|
GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
|
|
return GV;
|
|
}
|
|
|
|
/// \brief Create a global describing a source location.
|
|
static GlobalVariable *createPrivateGlobalForSourceLoc(Module &M,
|
|
LocationMetadata MD) {
|
|
Constant *LocData[] = {
|
|
createPrivateGlobalForString(M, MD.Filename, true),
|
|
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(true);
|
|
return GV;
|
|
}
|
|
|
|
static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
|
|
return G->getName().find(kAsanGenPrefix) == 0;
|
|
}
|
|
|
|
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
|
|
// Shadow >> scale
|
|
Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
|
|
if (Mapping.Offset == 0)
|
|
return Shadow;
|
|
// (Shadow >> scale) | offset
|
|
if (Mapping.OrShadowOffset)
|
|
return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
|
|
else
|
|
return IRB.CreateAdd(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
|
|
}
|
|
|
|
// Instrument memset/memmove/memcpy
|
|
void AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
|
|
IRBuilder<> IRB(MI);
|
|
if (isa<MemTransferInst>(MI)) {
|
|
IRB.CreateCall3(
|
|
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.CreateCall3(
|
|
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();
|
|
}
|
|
|
|
// If I is an interesting memory access, return the PointerOperand
|
|
// and set IsWrite/Alignment. Otherwise return NULL.
|
|
static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
|
|
unsigned *Alignment) {
|
|
// Skip memory accesses inserted by another instrumentation.
|
|
if (I->getMetadata("nosanitize"))
|
|
return nullptr;
|
|
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
|
|
if (!ClInstrumentReads) return nullptr;
|
|
*IsWrite = false;
|
|
*Alignment = LI->getAlignment();
|
|
return LI->getPointerOperand();
|
|
}
|
|
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
|
|
if (!ClInstrumentWrites) return nullptr;
|
|
*IsWrite = true;
|
|
*Alignment = SI->getAlignment();
|
|
return SI->getPointerOperand();
|
|
}
|
|
if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
|
|
if (!ClInstrumentAtomics) return nullptr;
|
|
*IsWrite = true;
|
|
*Alignment = 0;
|
|
return RMW->getPointerOperand();
|
|
}
|
|
if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
|
|
if (!ClInstrumentAtomics) return nullptr;
|
|
*IsWrite = true;
|
|
*Alignment = 0;
|
|
return XCHG->getPointerOperand();
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
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 isInterestingPointerComparisonOrSubtraction(Instruction *I) {
|
|
if (ICmpInst *Cmp = dyn_cast<ICmpInst>(I)) {
|
|
if (!Cmp->isRelational())
|
|
return false;
|
|
} else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
|
|
if (BO->getOpcode() != Instruction::Sub)
|
|
return false;
|
|
} else {
|
|
return false;
|
|
}
|
|
if (!isPointerOperand(I->getOperand(0)) ||
|
|
!isPointerOperand(I->getOperand(1)))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
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).
|
|
return G->hasInitializer() && !GlobalsMD.get(G).IsDynInit;
|
|
}
|
|
|
|
void
|
|
AddressSanitizer::instrumentPointerComparisonOrSubtraction(Instruction *I) {
|
|
IRBuilder<> IRB(I);
|
|
Function *F = isa<ICmpInst>(I) ? AsanPtrCmpFunction : AsanPtrSubFunction;
|
|
Value *Param[2] = {I->getOperand(0), I->getOperand(1)};
|
|
for (int i = 0; i < 2; i++) {
|
|
if (Param[i]->getType()->isPointerTy())
|
|
Param[i] = IRB.CreatePointerCast(Param[i], IntptrTy);
|
|
}
|
|
IRB.CreateCall2(F, Param[0], Param[1]);
|
|
}
|
|
|
|
void AddressSanitizer::instrumentMop(Instruction *I, bool UseCalls) {
|
|
bool IsWrite = false;
|
|
unsigned Alignment = 0;
|
|
Value *Addr = isInterestingMemoryAccess(I, &IsWrite, &Alignment);
|
|
assert(Addr);
|
|
if (ClOpt && ClOptGlobals) {
|
|
if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
|
|
// If initialization order checking is disabled, a simple access to a
|
|
// dynamically initialized global is always valid.
|
|
if (!ClInitializers || GlobalIsLinkerInitialized(G)) {
|
|
NumOptimizedAccessesToGlobalVar++;
|
|
return;
|
|
}
|
|
}
|
|
ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr);
|
|
if (CE && CE->isGEPWithNoNotionalOverIndexing()) {
|
|
if (GlobalVariable *G = dyn_cast<GlobalVariable>(CE->getOperand(0))) {
|
|
if (CE->getOperand(1)->isNullValue() && GlobalIsLinkerInitialized(G)) {
|
|
NumOptimizedAccessesToGlobalArray++;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
Type *OrigPtrTy = Addr->getType();
|
|
Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
|
|
|
|
assert(OrigTy->isSized());
|
|
uint32_t TypeSize = DL->getTypeStoreSizeInBits(OrigTy);
|
|
|
|
assert((TypeSize % 8) == 0);
|
|
|
|
if (IsWrite)
|
|
NumInstrumentedWrites++;
|
|
else
|
|
NumInstrumentedReads++;
|
|
|
|
unsigned Granularity = 1 << Mapping.Scale;
|
|
// 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 instrumentAddress(I, I, Addr, TypeSize, IsWrite, nullptr, UseCalls);
|
|
// 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.
|
|
IRBuilder<> IRB(I);
|
|
Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
if (UseCalls) {
|
|
IRB.CreateCall2(AsanMemoryAccessCallbackSized[IsWrite], AddrLong, Size);
|
|
} else {
|
|
Value *LastByte = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(AddrLong, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
|
|
OrigPtrTy);
|
|
instrumentAddress(I, I, Addr, 8, IsWrite, Size, false);
|
|
instrumentAddress(I, I, LastByte, 8, IsWrite, Size, false);
|
|
}
|
|
}
|
|
|
|
// Validate the result of Module::getOrInsertFunction called for an interface
|
|
// function of AddressSanitizer. If the instrumented module defines a function
|
|
// with the same name, their prototypes must match, otherwise
|
|
// getOrInsertFunction returns a bitcast.
|
|
static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
|
|
if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
|
|
FuncOrBitcast->dump();
|
|
report_fatal_error("trying to redefine an AddressSanitizer "
|
|
"interface function");
|
|
}
|
|
|
|
Instruction *AddressSanitizer::generateCrashCode(
|
|
Instruction *InsertBefore, Value *Addr,
|
|
bool IsWrite, size_t AccessSizeIndex, Value *SizeArgument) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
CallInst *Call = SizeArgument
|
|
? IRB.CreateCall2(AsanErrorCallbackSized[IsWrite], Addr, SizeArgument)
|
|
: IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr);
|
|
|
|
// 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 = 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) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
|
|
|
|
if (UseCalls) {
|
|
IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][AccessSizeIndex],
|
|
AddrLong);
|
|
return;
|
|
}
|
|
|
|
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(
|
|
IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
|
|
|
|
Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
|
|
size_t Granularity = 1 << Mapping.Scale;
|
|
TerminatorInst *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.
|
|
TerminatorInst *CheckTerm =
|
|
SplitBlockAndInsertIfThen(Cmp, InsertBefore, false,
|
|
MDBuilder(*C).createBranchWeights(1, 100000));
|
|
assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
|
|
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
|
|
IRB.SetInsertPoint(CheckTerm);
|
|
Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
|
|
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, true);
|
|
}
|
|
|
|
Instruction *Crash = generateCrashCode(
|
|
CrashTerm, AddrLong, IsWrite, AccessSizeIndex, SizeArgument);
|
|
Crash->setDebugLoc(OrigIns->getDebugLoc());
|
|
}
|
|
|
|
void AddressSanitizerModule::poisonOneInitializer(Function &GlobalInit,
|
|
GlobalValue *ModuleName) {
|
|
// Set up the arguments to our poison/unpoison functions.
|
|
IRBuilder<> IRB(GlobalInit.begin()->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 AddressSanitizerModule::createInitializerPoisonCalls(
|
|
Module &M, GlobalValue *ModuleName) {
|
|
GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
|
|
|
|
ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
|
|
for (Use &OP : CA->operands()) {
|
|
if (isa<ConstantAggregateZero>(OP))
|
|
continue;
|
|
ConstantStruct *CS = cast<ConstantStruct>(OP);
|
|
|
|
// Must have a function or null ptr.
|
|
// (CS->getOperand(0) is the init priority.)
|
|
if (Function* F = dyn_cast<Function>(CS->getOperand(1))) {
|
|
if (F->getName() != kAsanModuleCtorName)
|
|
poisonOneInitializer(*F, ModuleName);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
|
|
Type *Ty = cast<PointerType>(G->getType())->getElementType();
|
|
DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
|
|
|
|
if (GlobalsMD.get(G).IsBlacklisted) return false;
|
|
if (!Ty->isSized()) return false;
|
|
if (!G->hasInitializer()) return false;
|
|
if (GlobalWasGeneratedByAsan(G)) return false; // Our own global.
|
|
// Touch only those globals that will not be defined in other modules.
|
|
// Don't handle ODR linkage types and COMDATs since other modules may be built
|
|
// without ASan.
|
|
if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
|
|
G->getLinkage() != GlobalVariable::PrivateLinkage &&
|
|
G->getLinkage() != GlobalVariable::InternalLinkage)
|
|
return false;
|
|
if (G->hasComdat())
|
|
return false;
|
|
// 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;
|
|
|
|
// Ignore all the globals with the names starting with "\01L_OBJC_".
|
|
// Many of those are put into the .cstring section. The linker compresses
|
|
// that section by removing the spare \0s after the string terminator, so
|
|
// our redzones get broken.
|
|
if ((G->getName().find("\01L_OBJC_") == 0) ||
|
|
(G->getName().find("\01l_OBJC_") == 0)) {
|
|
DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G << "\n");
|
|
return false;
|
|
}
|
|
|
|
if (G->hasSection()) {
|
|
StringRef Section(G->getSection());
|
|
// 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 (Section.startswith("__OBJC,") ||
|
|
Section.startswith("__DATA, __objc_")) {
|
|
DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G << "\n");
|
|
return false;
|
|
}
|
|
// See http://code.google.com/p/address-sanitizer/issues/detail?id=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 (Section.startswith("__DATA,__cfstring")) {
|
|
DEBUG(dbgs() << "Ignoring CFString: " << *G << "\n");
|
|
return false;
|
|
}
|
|
// The linker merges the contents of cstring_literals and removes the
|
|
// trailing zeroes.
|
|
if (Section.startswith("__TEXT,__cstring,cstring_literals")) {
|
|
DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n");
|
|
return false;
|
|
}
|
|
|
|
// Callbacks put into the CRT initializer/terminator sections
|
|
// should not be instrumented.
|
|
// See https://code.google.com/p/address-sanitizer/issues/detail?id=305
|
|
// and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx
|
|
if (Section.startswith(".CRT")) {
|
|
DEBUG(dbgs() << "Ignoring a global initializer callback: " << *G << "\n");
|
|
return false;
|
|
}
|
|
|
|
// Globals from llvm.metadata aren't emitted, do not instrument them.
|
|
if (Section == "llvm.metadata") return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void AddressSanitizerModule::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
// Declare our poisoning and unpoisoning functions.
|
|
AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, NULL));
|
|
AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
|
|
AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
|
|
AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
|
|
// Declare functions that register/unregister globals.
|
|
AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanRegisterGlobalsName, IRB.getVoidTy(),
|
|
IntptrTy, IntptrTy, NULL));
|
|
AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
|
|
AsanUnregisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanUnregisterGlobalsName,
|
|
IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
|
|
AsanCovModuleInit = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanCovModuleInitName,
|
|
IRB.getVoidTy(), IntptrTy, NULL));
|
|
AsanCovModuleInit->setLinkage(Function::ExternalLinkage);
|
|
}
|
|
|
|
// 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.
|
|
bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
|
|
GlobalsMD.init(M);
|
|
|
|
SmallVector<GlobalVariable *, 16> GlobalsToChange;
|
|
|
|
for (auto &G : M.globals()) {
|
|
if (ShouldInstrumentGlobal(&G))
|
|
GlobalsToChange.push_back(&G);
|
|
}
|
|
|
|
size_t n = GlobalsToChange.size();
|
|
if (n == 0) return false;
|
|
|
|
// 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;
|
|
// 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, NULL);
|
|
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);
|
|
|
|
for (size_t i = 0; i < n; i++) {
|
|
static const uint64_t kMaxGlobalRedzone = 1 << 18;
|
|
GlobalVariable *G = GlobalsToChange[i];
|
|
|
|
auto MD = GlobalsMD.get(G);
|
|
// 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() ? G->getName() : MD.Name,
|
|
/*AllowMerging*/ true);
|
|
|
|
PointerType *PtrTy = cast<PointerType>(G->getType());
|
|
Type *Ty = PtrTy->getElementType();
|
|
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, NULL);
|
|
Constant *NewInitializer = ConstantStruct::get(
|
|
NewTy, G->getInitializer(),
|
|
Constant::getNullValue(RightRedZoneTy), NULL);
|
|
|
|
// 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->setAlignment(MinRZ);
|
|
|
|
Value *Indices2[2];
|
|
Indices2[0] = IRB.getInt32(0);
|
|
Indices2[1] = IRB.getInt32(0);
|
|
|
|
G->replaceAllUsesWith(
|
|
ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
|
|
NewGlobal->takeName(G);
|
|
G->eraseFromParent();
|
|
|
|
Constant *SourceLoc;
|
|
if (!MD.SourceLoc.empty()) {
|
|
auto SourceLocGlobal = createPrivateGlobalForSourceLoc(M, MD.SourceLoc);
|
|
SourceLoc = ConstantExpr::getPointerCast(SourceLocGlobal, IntptrTy);
|
|
} else {
|
|
SourceLoc = ConstantInt::get(IntptrTy, 0);
|
|
}
|
|
|
|
Initializers[i] = ConstantStruct::get(
|
|
GlobalStructTy, ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
|
|
ConstantInt::get(IntptrTy, SizeInBytes),
|
|
ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
|
|
ConstantExpr::getPointerCast(Name, IntptrTy),
|
|
ConstantExpr::getPointerCast(ModuleName, IntptrTy),
|
|
ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, NULL);
|
|
|
|
if (ClInitializers && MD.IsDynInit)
|
|
HasDynamicallyInitializedGlobals = true;
|
|
|
|
DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
|
|
}
|
|
|
|
ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
|
|
GlobalVariable *AllGlobals = new GlobalVariable(
|
|
M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
|
|
ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
|
|
|
|
// Create calls for poisoning before initializers run and unpoisoning after.
|
|
if (HasDynamicallyInitializedGlobals)
|
|
createInitializerPoisonCalls(M, ModuleName);
|
|
IRB.CreateCall2(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.
|
|
Function *AsanDtorFunction = Function::Create(
|
|
FunctionType::get(Type::getVoidTy(*C), false),
|
|
GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
|
|
BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
|
|
IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
|
|
IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
|
|
IRB.CreatePointerCast(AllGlobals, IntptrTy),
|
|
ConstantInt::get(IntptrTy, n));
|
|
appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
|
|
|
|
DEBUG(dbgs() << M);
|
|
return true;
|
|
}
|
|
|
|
bool AddressSanitizerModule::runOnModule(Module &M) {
|
|
DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
|
|
if (!DLP)
|
|
return false;
|
|
DL = &DLP->getDataLayout();
|
|
C = &(M.getContext());
|
|
int LongSize = DL->getPointerSizeInBits();
|
|
IntptrTy = Type::getIntNTy(*C, LongSize);
|
|
Mapping = getShadowMapping(M, LongSize);
|
|
initializeCallbacks(M);
|
|
|
|
bool Changed = false;
|
|
|
|
Function *CtorFunc = M.getFunction(kAsanModuleCtorName);
|
|
assert(CtorFunc);
|
|
IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
|
|
|
|
if (ClCoverage > 0) {
|
|
Function *CovFunc = M.getFunction(kAsanCovName);
|
|
int nCov = CovFunc ? CovFunc->getNumUses() : 0;
|
|
IRB.CreateCall(AsanCovModuleInit, ConstantInt::get(IntptrTy, nCov));
|
|
Changed = true;
|
|
}
|
|
|
|
if (ClGlobals)
|
|
Changed |= InstrumentGlobals(IRB, M);
|
|
|
|
return Changed;
|
|
}
|
|
|
|
void AddressSanitizer::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
// Create __asan_report* callbacks.
|
|
for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
|
|
for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
|
|
AccessSizeIndex++) {
|
|
// IsWrite and TypeSize are encoded in the function name.
|
|
std::string Suffix =
|
|
(AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
|
|
AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
|
|
checkInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanReportErrorTemplate + Suffix,
|
|
IRB.getVoidTy(), IntptrTy, NULL));
|
|
AsanMemoryAccessCallback[AccessIsWrite][AccessSizeIndex] =
|
|
checkInterfaceFunction(
|
|
M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + Suffix,
|
|
IRB.getVoidTy(), IntptrTy, NULL));
|
|
}
|
|
}
|
|
AsanErrorCallbackSized[0] = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
AsanErrorCallbackSized[1] = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanReportStoreN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
|
|
AsanMemoryAccessCallbackSized[0] = checkInterfaceFunction(
|
|
M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "loadN",
|
|
IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
AsanMemoryAccessCallbackSized[1] = checkInterfaceFunction(
|
|
M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "storeN",
|
|
IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
|
|
AsanMemmove = checkInterfaceFunction(M.getOrInsertFunction(
|
|
ClMemoryAccessCallbackPrefix + "memmove", IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, NULL));
|
|
AsanMemcpy = checkInterfaceFunction(M.getOrInsertFunction(
|
|
ClMemoryAccessCallbackPrefix + "memcpy", IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, NULL));
|
|
AsanMemset = checkInterfaceFunction(M.getOrInsertFunction(
|
|
ClMemoryAccessCallbackPrefix + "memset", IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy, NULL));
|
|
|
|
AsanHandleNoReturnFunc = checkInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
|
|
AsanCovFunction = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanCovName, IRB.getVoidTy(), NULL));
|
|
AsanPtrCmpFunction = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
AsanPtrSubFunction = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
// 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);
|
|
}
|
|
|
|
// virtual
|
|
bool AddressSanitizer::doInitialization(Module &M) {
|
|
// Initialize the private fields. No one has accessed them before.
|
|
DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
|
|
if (!DLP)
|
|
report_fatal_error("data layout missing");
|
|
DL = &DLP->getDataLayout();
|
|
|
|
GlobalsMD.init(M);
|
|
|
|
C = &(M.getContext());
|
|
LongSize = DL->getPointerSizeInBits();
|
|
IntptrTy = Type::getIntNTy(*C, LongSize);
|
|
|
|
AsanCtorFunction = Function::Create(
|
|
FunctionType::get(Type::getVoidTy(*C), false),
|
|
GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
|
|
BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
|
|
// call __asan_init in the module ctor.
|
|
IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB));
|
|
AsanInitFunction = checkInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
|
|
AsanInitFunction->setLinkage(Function::ExternalLinkage);
|
|
IRB.CreateCall(AsanInitFunction);
|
|
|
|
Mapping = getShadowMapping(M, LongSize);
|
|
|
|
appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
|
|
return true;
|
|
}
|
|
|
|
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) {
|
|
IRBuilder<> IRB(F.begin()->begin());
|
|
IRB.CreateCall(AsanInitFunction);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void AddressSanitizer::InjectCoverageAtBlock(Function &F, BasicBlock &BB) {
|
|
BasicBlock::iterator IP = BB.getFirstInsertionPt(), BE = BB.end();
|
|
// Skip static allocas at the top of the entry block so they don't become
|
|
// dynamic when we split the block. If we used our optimized stack layout,
|
|
// then there will only be one alloca and it will come first.
|
|
for (; IP != BE; ++IP) {
|
|
AllocaInst *AI = dyn_cast<AllocaInst>(IP);
|
|
if (!AI || !AI->isStaticAlloca())
|
|
break;
|
|
}
|
|
|
|
DebugLoc EntryLoc = IP->getDebugLoc().getFnDebugLoc(*C);
|
|
IRBuilder<> IRB(IP);
|
|
IRB.SetCurrentDebugLocation(EntryLoc);
|
|
Type *Int8Ty = IRB.getInt8Ty();
|
|
GlobalVariable *Guard = new GlobalVariable(
|
|
*F.getParent(), Int8Ty, false, GlobalValue::PrivateLinkage,
|
|
Constant::getNullValue(Int8Ty), "__asan_gen_cov_" + F.getName());
|
|
LoadInst *Load = IRB.CreateLoad(Guard);
|
|
Load->setAtomic(Monotonic);
|
|
Load->setAlignment(1);
|
|
Value *Cmp = IRB.CreateICmpEQ(Constant::getNullValue(Int8Ty), Load);
|
|
Instruction *Ins = SplitBlockAndInsertIfThen(
|
|
Cmp, IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
|
|
IRB.SetInsertPoint(Ins);
|
|
IRB.SetCurrentDebugLocation(EntryLoc);
|
|
// __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
|
|
IRB.CreateCall(AsanCovFunction);
|
|
StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard);
|
|
Store->setAtomic(Monotonic);
|
|
Store->setAlignment(1);
|
|
}
|
|
|
|
// Poor man's coverage that works with ASan.
|
|
// We create a Guard boolean variable with the same linkage
|
|
// as the function and inject this code into the entry block (-asan-coverage=1)
|
|
// or all blocks (-asan-coverage=2):
|
|
// if (*Guard) {
|
|
// __sanitizer_cov();
|
|
// *Guard = 1;
|
|
// }
|
|
// The accesses to Guard are atomic. The rest of the logic is
|
|
// in __sanitizer_cov (it's fine to call it more than once).
|
|
//
|
|
// This coverage implementation provides very limited data:
|
|
// it only tells if a given function (block) was ever executed.
|
|
// No counters, no per-edge data.
|
|
// But for many use cases this is what we need and the added slowdown
|
|
// is negligible. This simple implementation will probably be obsoleted
|
|
// by the upcoming Clang-based coverage implementation.
|
|
// By having it here and now we hope to
|
|
// a) get the functionality to users earlier and
|
|
// b) collect usage statistics to help improve Clang coverage design.
|
|
bool AddressSanitizer::InjectCoverage(Function &F,
|
|
ArrayRef<BasicBlock *> AllBlocks) {
|
|
if (!ClCoverage) return false;
|
|
|
|
if (ClCoverage == 1 ||
|
|
(unsigned)ClCoverageBlockThreshold < AllBlocks.size()) {
|
|
InjectCoverageAtBlock(F, F.getEntryBlock());
|
|
} else {
|
|
for (auto BB : AllBlocks)
|
|
InjectCoverageAtBlock(F, *BB);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool AddressSanitizer::runOnFunction(Function &F) {
|
|
if (&F == AsanCtorFunction) return false;
|
|
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
|
|
DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
|
|
initializeCallbacks(*F.getParent());
|
|
|
|
// If needed, insert __asan_init before checking for SanitizeAddress attr.
|
|
maybeInsertAsanInitAtFunctionEntry(F);
|
|
|
|
if (!F.hasFnAttribute(Attribute::SanitizeAddress))
|
|
return false;
|
|
|
|
if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
|
|
return false;
|
|
|
|
// We want to instrument every address only once per basic block (unless there
|
|
// are calls between uses).
|
|
SmallSet<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;
|
|
|
|
// 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;
|
|
if (Value *Addr =
|
|
isInterestingMemoryAccess(&Inst, &IsWrite, &Alignment)) {
|
|
if (ClOpt && ClOptSameTemp) {
|
|
if (!TempsToInstrument.insert(Addr))
|
|
continue; // We've seen this temp in the current BB.
|
|
}
|
|
} else if (ClInvalidPointerPairs &&
|
|
isInterestingPointerComparisonOrSubtraction(&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())
|
|
NoReturnCalls.push_back(CS.getInstruction());
|
|
}
|
|
continue;
|
|
}
|
|
ToInstrument.push_back(&Inst);
|
|
NumInsnsPerBB++;
|
|
if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
|
|
break;
|
|
}
|
|
}
|
|
|
|
Function *UninstrumentedDuplicate = nullptr;
|
|
bool LikelyToInstrument =
|
|
!NoReturnCalls.empty() || !ToInstrument.empty() || (NumAllocas > 0);
|
|
if (ClKeepUninstrumented && LikelyToInstrument) {
|
|
ValueToValueMapTy VMap;
|
|
UninstrumentedDuplicate = CloneFunction(&F, VMap, false);
|
|
UninstrumentedDuplicate->removeFnAttr(Attribute::SanitizeAddress);
|
|
UninstrumentedDuplicate->setName("NOASAN_" + F.getName());
|
|
F.getParent()->getFunctionList().push_back(UninstrumentedDuplicate);
|
|
}
|
|
|
|
bool UseCalls = false;
|
|
if (ClInstrumentationWithCallsThreshold >= 0 &&
|
|
ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold)
|
|
UseCalls = true;
|
|
|
|
// Instrument.
|
|
int NumInstrumented = 0;
|
|
for (auto Inst : ToInstrument) {
|
|
if (ClDebugMin < 0 || ClDebugMax < 0 ||
|
|
(NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
|
|
if (isInterestingMemoryAccess(Inst, &IsWrite, &Alignment))
|
|
instrumentMop(Inst, UseCalls);
|
|
else
|
|
instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
|
|
}
|
|
NumInstrumented++;
|
|
}
|
|
|
|
FunctionStackPoisoner FSP(F, *this);
|
|
bool ChangedStack = FSP.runOnFunction();
|
|
|
|
// We must unpoison the stack before every NoReturn call (throw, _exit, etc).
|
|
// See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
|
|
for (auto CI : NoReturnCalls) {
|
|
IRBuilder<> IRB(CI);
|
|
IRB.CreateCall(AsanHandleNoReturnFunc);
|
|
}
|
|
|
|
for (auto Inst : PointerComparisonsOrSubtracts) {
|
|
instrumentPointerComparisonOrSubtraction(Inst);
|
|
NumInstrumented++;
|
|
}
|
|
|
|
bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
|
|
|
|
if (InjectCoverage(F, AllBlocks))
|
|
res = true;
|
|
|
|
DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
|
|
|
|
if (ClKeepUninstrumented) {
|
|
if (!res) {
|
|
// No instrumentation is done, no need for the duplicate.
|
|
if (UninstrumentedDuplicate)
|
|
UninstrumentedDuplicate->eraseFromParent();
|
|
} else {
|
|
// The function was instrumented. We must have the duplicate.
|
|
assert(UninstrumentedDuplicate);
|
|
UninstrumentedDuplicate->setSection("NOASAN");
|
|
assert(!F.hasSection());
|
|
F.setSection("ASAN");
|
|
}
|
|
}
|
|
|
|
return res;
|
|
}
|
|
|
|
// 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] = checkInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy,
|
|
IntptrTy, IntptrTy, NULL));
|
|
AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy,
|
|
IntptrTy, IntptrTy, NULL));
|
|
}
|
|
AsanPoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanPoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanUnpoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
|
|
}
|
|
|
|
void
|
|
FunctionStackPoisoner::poisonRedZones(ArrayRef<uint8_t> ShadowBytes,
|
|
IRBuilder<> &IRB, Value *ShadowBase,
|
|
bool DoPoison) {
|
|
size_t n = ShadowBytes.size();
|
|
size_t i = 0;
|
|
// We need to (un)poison n bytes of stack shadow. Poison as many as we can
|
|
// using 64-bit stores (if we are on 64-bit arch), then poison the rest
|
|
// with 32-bit stores, then with 16-byte stores, then with 8-byte stores.
|
|
for (size_t LargeStoreSizeInBytes = ASan.LongSize / 8;
|
|
LargeStoreSizeInBytes != 0; LargeStoreSizeInBytes /= 2) {
|
|
for (; i + LargeStoreSizeInBytes - 1 < n; i += LargeStoreSizeInBytes) {
|
|
uint64_t Val = 0;
|
|
for (size_t j = 0; j < LargeStoreSizeInBytes; j++) {
|
|
if (ASan.DL->isLittleEndian())
|
|
Val |= (uint64_t)ShadowBytes[i + j] << (8 * j);
|
|
else
|
|
Val = (Val << 8) | ShadowBytes[i + j];
|
|
}
|
|
if (!Val) continue;
|
|
Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
|
|
Type *StoreTy = Type::getIntNTy(*C, LargeStoreSizeInBytes * 8);
|
|
Value *Poison = ConstantInt::get(StoreTy, DoPoison ? Val : 0);
|
|
IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, StoreTy->getPointerTo()));
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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");
|
|
}
|
|
|
|
// Set Size bytes starting from ShadowBase to kAsanStackAfterReturnMagic.
|
|
// We can not use MemSet intrinsic because it may end up calling the actual
|
|
// memset. Size is a multiple of 8.
|
|
// Currently this generates 8-byte stores on x86_64; it may be better to
|
|
// generate wider stores.
|
|
void FunctionStackPoisoner::SetShadowToStackAfterReturnInlined(
|
|
IRBuilder<> &IRB, Value *ShadowBase, int Size) {
|
|
assert(!(Size % 8));
|
|
assert(kAsanStackAfterReturnMagic == 0xf5);
|
|
for (int i = 0; i < Size; i += 8) {
|
|
Value *p = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
|
|
IRB.CreateStore(ConstantInt::get(IRB.getInt64Ty(), 0xf5f5f5f5f5f5f5f5ULL),
|
|
IRB.CreateIntToPtr(p, IRB.getInt64Ty()->getPointerTo()));
|
|
}
|
|
}
|
|
|
|
static DebugLoc getFunctionEntryDebugLocation(Function &F) {
|
|
for (const auto &Inst : F.getEntryBlock())
|
|
if (!isa<AllocaInst>(Inst))
|
|
return Inst.getDebugLoc();
|
|
return DebugLoc();
|
|
}
|
|
|
|
void FunctionStackPoisoner::poisonStack() {
|
|
int StackMallocIdx = -1;
|
|
DebugLoc EntryDebugLocation = getFunctionEntryDebugLocation(F);
|
|
|
|
assert(AllocaVec.size() > 0);
|
|
Instruction *InsBefore = AllocaVec[0];
|
|
IRBuilder<> IRB(InsBefore);
|
|
IRB.SetCurrentDebugLocation(EntryDebugLocation);
|
|
|
|
SmallVector<ASanStackVariableDescription, 16> SVD;
|
|
SVD.reserve(AllocaVec.size());
|
|
for (AllocaInst *AI : AllocaVec) {
|
|
ASanStackVariableDescription D = { AI->getName().data(),
|
|
getAllocaSizeInBytes(AI),
|
|
AI->getAlignment(), AI, 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 MinHeaderSize = ASan.LongSize / 2;
|
|
ASanStackFrameLayout L;
|
|
ComputeASanStackFrameLayout(SVD, 1UL << Mapping.Scale, MinHeaderSize, &L);
|
|
DEBUG(dbgs() << L.DescriptionString << " --- " << L.FrameSize << "\n");
|
|
uint64_t LocalStackSize = L.FrameSize;
|
|
bool DoStackMalloc =
|
|
ClUseAfterReturn && LocalStackSize <= kMaxStackMallocSize;
|
|
|
|
Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
|
|
AllocaInst *MyAlloca =
|
|
new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
|
|
MyAlloca->setDebugLoc(EntryDebugLocation);
|
|
assert((ClRealignStack & (ClRealignStack - 1)) == 0);
|
|
size_t FrameAlignment = std::max(L.FrameAlignment, (size_t)ClRealignStack);
|
|
MyAlloca->setAlignment(FrameAlignment);
|
|
assert(MyAlloca->isStaticAlloca());
|
|
Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
|
|
Value *LocalStackBase = OrigStackBase;
|
|
|
|
if (DoStackMalloc) {
|
|
// LocalStackBase = OrigStackBase
|
|
// if (__asan_option_detect_stack_use_after_return)
|
|
// LocalStackBase = __asan_stack_malloc_N(LocalStackBase, OrigStackBase);
|
|
StackMallocIdx = StackMallocSizeClass(LocalStackSize);
|
|
assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
|
|
Constant *OptionDetectUAR = F.getParent()->getOrInsertGlobal(
|
|
kAsanOptionDetectUAR, IRB.getInt32Ty());
|
|
Value *Cmp = IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUAR),
|
|
Constant::getNullValue(IRB.getInt32Ty()));
|
|
Instruction *Term = SplitBlockAndInsertIfThen(Cmp, InsBefore, false);
|
|
BasicBlock *CmpBlock = cast<Instruction>(Cmp)->getParent();
|
|
IRBuilder<> IRBIf(Term);
|
|
IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
|
|
LocalStackBase = IRBIf.CreateCall2(
|
|
AsanStackMallocFunc[StackMallocIdx],
|
|
ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
|
|
BasicBlock *SetBlock = cast<Instruction>(LocalStackBase)->getParent();
|
|
IRB.SetInsertPoint(InsBefore);
|
|
IRB.SetCurrentDebugLocation(EntryDebugLocation);
|
|
PHINode *Phi = IRB.CreatePHI(IntptrTy, 2);
|
|
Phi->addIncoming(OrigStackBase, CmpBlock);
|
|
Phi->addIncoming(LocalStackBase, SetBlock);
|
|
LocalStackBase = Phi;
|
|
}
|
|
|
|
// Insert poison calls for lifetime intrinsics for alloca.
|
|
bool HavePoisonedAllocas = false;
|
|
for (const auto &APC : AllocaPoisonCallVec) {
|
|
assert(APC.InsBefore);
|
|
assert(APC.AI);
|
|
IRBuilder<> IRB(APC.InsBefore);
|
|
poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison);
|
|
HavePoisonedAllocas |= APC.DoPoison;
|
|
}
|
|
|
|
// Replace Alloca instructions with base+offset.
|
|
for (const auto &Desc : SVD) {
|
|
AllocaInst *AI = Desc.AI;
|
|
Value *NewAllocaPtr = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)),
|
|
AI->getType());
|
|
replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB);
|
|
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(), L.DescriptionString,
|
|
/*AllowMerging*/true);
|
|
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);
|
|
|
|
// Poison the stack redzones at the entry.
|
|
Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB);
|
|
poisonRedZones(L.ShadowBytes, IRB, ShadowBase, true);
|
|
|
|
// (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 LocalStackBase != OrigStackBase:
|
|
// // 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(LocalStackBase) = 0
|
|
// else
|
|
// __asan_stack_free_N(LocalStackBase, OrigStackBase)
|
|
// else
|
|
// <This is not a fake stack; unpoison the redzones>
|
|
Value *Cmp = IRBRet.CreateICmpNE(LocalStackBase, OrigStackBase);
|
|
TerminatorInst *ThenTerm, *ElseTerm;
|
|
SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm);
|
|
|
|
IRBuilder<> IRBPoison(ThenTerm);
|
|
if (StackMallocIdx <= 4) {
|
|
int ClassSize = kMinStackMallocSize << StackMallocIdx;
|
|
SetShadowToStackAfterReturnInlined(IRBPoison, ShadowBase,
|
|
ClassSize >> Mapping.Scale);
|
|
Value *SavedFlagPtrPtr = IRBPoison.CreateAdd(
|
|
LocalStackBase,
|
|
ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8));
|
|
Value *SavedFlagPtr = IRBPoison.CreateLoad(
|
|
IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy));
|
|
IRBPoison.CreateStore(
|
|
Constant::getNullValue(IRBPoison.getInt8Ty()),
|
|
IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy()));
|
|
} else {
|
|
// For larger frames call __asan_stack_free_*.
|
|
IRBPoison.CreateCall3(AsanStackFreeFunc[StackMallocIdx], LocalStackBase,
|
|
ConstantInt::get(IntptrTy, LocalStackSize),
|
|
OrigStackBase);
|
|
}
|
|
|
|
IRBuilder<> IRBElse(ElseTerm);
|
|
poisonRedZones(L.ShadowBytes, IRBElse, ShadowBase, false);
|
|
} else if (HavePoisonedAllocas) {
|
|
// If we poisoned some allocas in llvm.lifetime analysis,
|
|
// unpoison whole stack frame now.
|
|
assert(LocalStackBase == OrigStackBase);
|
|
poisonAlloca(LocalStackBase, LocalStackSize, IRBRet, false);
|
|
} else {
|
|
poisonRedZones(L.ShadowBytes, IRBRet, ShadowBase, false);
|
|
}
|
|
}
|
|
|
|
// 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.CreateCall2(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.
|
|
|
|
AllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) {
|
|
if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
|
|
// We're intested only in allocas we can handle.
|
|
return isInterestingAlloca(*AI) ? AI : nullptr;
|
|
// See if we've already calculated (or started to calculate) alloca for a
|
|
// given value.
|
|
AllocaForValueMapTy::iterator I = AllocaForValue.find(V);
|
|
if (I != AllocaForValue.end())
|
|
return I->second;
|
|
// Store 0 while we're calculating alloca for value V to avoid
|
|
// infinite recursion if the value references itself.
|
|
AllocaForValue[V] = nullptr;
|
|
AllocaInst *Res = nullptr;
|
|
if (CastInst *CI = dyn_cast<CastInst>(V))
|
|
Res = findAllocaForValue(CI->getOperand(0));
|
|
else if (PHINode *PN = dyn_cast<PHINode>(V)) {
|
|
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
|
|
Value *IncValue = PN->getIncomingValue(i);
|
|
// Allow self-referencing phi-nodes.
|
|
if (IncValue == PN) continue;
|
|
AllocaInst *IncValueAI = findAllocaForValue(IncValue);
|
|
// AI for incoming values should exist and should all be equal.
|
|
if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
|
|
return nullptr;
|
|
Res = IncValueAI;
|
|
}
|
|
}
|
|
if (Res)
|
|
AllocaForValue[V] = Res;
|
|
return Res;
|
|
}
|