forked from OSchip/llvm-project
1454 lines
58 KiB
C++
1454 lines
58 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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#define DEBUG_TYPE "asan"
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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/DepthFirstIterator.h"
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#include "llvm/ADT/OwningPtr.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/StringExtras.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/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/IntrinsicInst.h"
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#include "llvm/IR/LLVMContext.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/InstVisitor.h"
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#include "llvm/Support/CallSite.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/raw_ostream.h"
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#include "llvm/Support/system_error.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/BlackList.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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using namespace llvm;
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static const uint64_t kDefaultShadowScale = 3;
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static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
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static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
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static const uint64_t kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G.
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static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
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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 *kAsanModuleCtorName = "asan.module_ctor";
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static const char *kAsanModuleDtorName = "asan.module_dtor";
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static const int kAsanCtorAndCtorPriority = 1;
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static const char *kAsanReportErrorTemplate = "__asan_report_";
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static const char *kAsanReportLoadN = "__asan_report_load_n";
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static const char *kAsanReportStoreN = "__asan_report_store_n";
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static const char *kAsanRegisterGlobalsName = "__asan_register_globals";
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static const char *kAsanUnregisterGlobalsName = "__asan_unregister_globals";
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static const char *kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
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static const char *kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
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static const char *kAsanInitName = "__asan_init_v3";
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static const char *kAsanHandleNoReturnName = "__asan_handle_no_return";
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static const char *kAsanMappingOffsetName = "__asan_mapping_offset";
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static const char *kAsanMappingScaleName = "__asan_mapping_scale";
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static const char *kAsanStackMallocName = "__asan_stack_malloc";
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static const char *kAsanStackFreeName = "__asan_stack_free";
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static const char *kAsanGenPrefix = "__asan_gen_";
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static const char *kAsanPoisonStackMemoryName = "__asan_poison_stack_memory";
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static const char *kAsanUnpoisonStackMemoryName =
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"__asan_unpoison_stack_memory";
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static const int kAsanStackLeftRedzoneMagic = 0xf1;
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static const int kAsanStackMidRedzoneMagic = 0xf2;
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static const int kAsanStackRightRedzoneMagic = 0xf3;
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static const int kAsanStackPartialRedzoneMagic = 0xf4;
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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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// This flag may need to be replaced with -f[no]asan-use-after-return.
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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(false));
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// This flag may need to be replaced with -f[no]asan-globals.
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static cl::opt<bool> ClGlobals("asan-globals",
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cl::desc("Handle global objects"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInitializers("asan-initialization-order",
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cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(false));
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static cl::opt<bool> ClMemIntrin("asan-memintrin",
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cl::desc("Handle memset/memcpy/memmove"), cl::Hidden, cl::init(true));
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static cl::opt<bool> ClRealignStack("asan-realign-stack",
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cl::desc("Realign stack to 32"), cl::Hidden, cl::init(true));
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static cl::opt<std::string> ClBlacklistFile("asan-blacklist",
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cl::desc("File containing the list of objects to ignore "
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"during instrumentation"), cl::Hidden);
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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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static cl::opt<int> ClMappingOffsetLog("asan-mapping-offset-log",
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cl::desc("offset of asan shadow mapping"), cl::Hidden, cl::init(-1));
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static cl::opt<bool> ClShort64BitOffset("asan-short-64bit-mapping-offset",
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cl::desc("Use short immediate constant as the mapping offset for 64bit"),
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cl::Hidden, cl::init(true));
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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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namespace {
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/// A set of dynamically initialized globals extracted from metadata.
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class SetOfDynamicallyInitializedGlobals {
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public:
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void Init(Module& M) {
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// Clang generates metadata identifying all dynamically initialized globals.
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NamedMDNode *DynamicGlobals =
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M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
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if (!DynamicGlobals)
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return;
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for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
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MDNode *MDN = DynamicGlobals->getOperand(i);
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assert(MDN->getNumOperands() == 1);
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Value *VG = MDN->getOperand(0);
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// The optimizer may optimize away a global entirely, in which case we
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// cannot instrument access to it.
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if (!VG)
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continue;
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DynInitGlobals.insert(cast<GlobalVariable>(VG));
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}
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}
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bool Contains(GlobalVariable *G) { return DynInitGlobals.count(G) != 0; }
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private:
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SmallSet<GlobalValue*, 32> DynInitGlobals;
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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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bool ZeroBaseShadow) {
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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 IsMacOSX = TargetTriple.getOS() == llvm::Triple::MacOSX;
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bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64;
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bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
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ShadowMapping Mapping;
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// OR-ing shadow offset if more efficient (at least on x86),
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// but on ppc64 we have to use add since the shadow offset is not neccesary
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// 1/8-th of the address space.
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Mapping.OrShadowOffset = !IsPPC64 && !ClShort64BitOffset;
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Mapping.Offset = (IsAndroid || ZeroBaseShadow) ? 0 :
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(LongSize == 32 ? kDefaultShadowOffset32 :
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IsPPC64 ? kPPC64_ShadowOffset64 : kDefaultShadowOffset64);
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if (!ZeroBaseShadow && ClShort64BitOffset && IsX86_64 && !IsMacOSX) {
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assert(LongSize == 64);
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Mapping.Offset = kDefaultShort64bitShadowOffset;
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}
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if (!ZeroBaseShadow && ClMappingOffsetLog >= 0) {
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// Zero offset log is the special case.
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Mapping.Offset = (ClMappingOffsetLog == 0) ? 0 : 1ULL << ClMappingOffsetLog;
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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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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(bool CheckInitOrder = true,
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bool CheckUseAfterReturn = false,
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bool CheckLifetime = false,
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StringRef BlacklistFile = StringRef(),
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bool ZeroBaseShadow = false)
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: FunctionPass(ID),
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CheckInitOrder(CheckInitOrder || ClInitializers),
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CheckUseAfterReturn(CheckUseAfterReturn || ClUseAfterReturn),
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CheckLifetime(CheckLifetime || ClCheckLifetime),
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BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile
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: BlacklistFile),
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ZeroBaseShadow(ZeroBaseShadow) {}
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virtual const char *getPassName() const {
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return "AddressSanitizerFunctionPass";
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}
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void instrumentMop(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);
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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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bool instrumentMemIntrinsic(MemIntrinsic *MI);
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void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr,
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Value *Size,
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Instruction *InsertBefore, bool IsWrite);
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Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
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bool runOnFunction(Function &F);
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bool maybeInsertAsanInitAtFunctionEntry(Function &F);
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void emitShadowMapping(Module &M, IRBuilder<> &IRB) const;
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virtual bool doInitialization(Module &M);
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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 ShouldInstrumentGlobal(GlobalVariable *G);
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bool LooksLikeCodeInBug11395(Instruction *I);
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void FindDynamicInitializers(Module &M);
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bool CheckInitOrder;
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bool CheckUseAfterReturn;
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bool CheckLifetime;
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SmallString<64> BlacklistFile;
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bool ZeroBaseShadow;
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LLVMContext *C;
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DataLayout *TD;
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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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OwningPtr<BlackList> BL;
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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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// This array is indexed by AccessIsWrite.
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Function *AsanErrorCallbackSized[2];
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InlineAsm *EmptyAsm;
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SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
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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(bool CheckInitOrder = true,
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StringRef BlacklistFile = StringRef(),
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bool ZeroBaseShadow = false)
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: ModulePass(ID),
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CheckInitOrder(CheckInitOrder || ClInitializers),
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BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile
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: BlacklistFile),
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ZeroBaseShadow(ZeroBaseShadow) {}
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bool runOnModule(Module &M);
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static char ID; // Pass identification, replacement for typeid
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virtual const char *getPassName() const {
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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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bool ShouldInstrumentGlobal(GlobalVariable *G);
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void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName);
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size_t RedzoneSize() const {
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return RedzoneSizeForScale(Mapping.Scale);
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}
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bool CheckInitOrder;
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SmallString<64> BlacklistFile;
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bool ZeroBaseShadow;
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OwningPtr<BlackList> BL;
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SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
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Type *IntptrTy;
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LLVMContext *C;
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DataLayout *TD;
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ShadowMapping Mapping;
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Function *AsanPoisonGlobals;
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Function *AsanUnpoisonGlobals;
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Function *AsanRegisterGlobals;
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Function *AsanUnregisterGlobals;
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};
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// Stack poisoning does not play well with exception handling.
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// When an exception is thrown, we essentially bypass the code
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// that unpoisones the stack. This is why the run-time library has
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// to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
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// stack in the interceptor. This however does not work inside the
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// actual function which catches the exception. Most likely because the
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// compiler hoists the load of the shadow value somewhere too high.
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// This causes asan to report a non-existing bug on 453.povray.
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// It sounds like an LLVM bug.
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struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
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Function &F;
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AddressSanitizer &ASan;
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DIBuilder DIB;
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LLVMContext *C;
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Type *IntptrTy;
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Type *IntptrPtrTy;
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ShadowMapping Mapping;
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SmallVector<AllocaInst*, 16> AllocaVec;
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SmallVector<Instruction*, 8> RetVec;
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uint64_t TotalStackSize;
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unsigned StackAlignment;
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Function *AsanStackMallocFunc, *AsanStackFreeFunc;
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Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc;
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// Stores a place and arguments of poisoning/unpoisoning call for alloca.
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struct AllocaPoisonCall {
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IntrinsicInst *InsBefore;
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uint64_t Size;
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bool DoPoison;
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};
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SmallVector<AllocaPoisonCall, 8> AllocaPoisonCallVec;
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// Maps Value to an AllocaInst from which the Value is originated.
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typedef DenseMap<Value*, AllocaInst*> AllocaForValueMapTy;
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AllocaForValueMapTy AllocaForValue;
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FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
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: F(F), ASan(ASan), DIB(*F.getParent()), C(ASan.C),
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IntptrTy(ASan.IntptrTy), IntptrPtrTy(PointerType::get(IntptrTy, 0)),
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Mapping(ASan.Mapping),
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TotalStackSize(0), StackAlignment(1 << Mapping.Scale) {}
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bool runOnFunction() {
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if (!ClStack) return false;
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// Collect alloca, ret, lifetime instructions etc.
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for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
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DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
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BasicBlock *BB = *DI;
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visit(*BB);
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}
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if (AllocaVec.empty()) return false;
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initializeCallbacks(*F.getParent());
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poisonStack();
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if (ClDebugStack) {
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DEBUG(dbgs() << F);
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}
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return true;
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}
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// Finds all static Alloca instructions and puts
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// poisoned red zones around all of them.
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// Then unpoison everything back before the function returns.
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void poisonStack();
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// ----------------------- Visitors.
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/// \brief Collect all Ret instructions.
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void visitReturnInst(ReturnInst &RI) {
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RetVec.push_back(&RI);
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}
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/// \brief Collect Alloca instructions we want (and can) handle.
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void visitAllocaInst(AllocaInst &AI) {
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if (!isInterestingAlloca(AI)) return;
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StackAlignment = std::max(StackAlignment, AI.getAlignment());
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AllocaVec.push_back(&AI);
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uint64_t AlignedSize = getAlignedAllocaSize(&AI);
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TotalStackSize += AlignedSize;
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}
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|
|
/// \brief Collect lifetime intrinsic calls to check for use-after-scope
|
|
/// errors.
|
|
void visitIntrinsicInst(IntrinsicInst &II) {
|
|
if (!ASan.CheckLifetime) 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, SizeValue, DoPoison};
|
|
AllocaPoisonCallVec.push_back(APC);
|
|
}
|
|
|
|
// ---------------------- Helpers.
|
|
void initializeCallbacks(Module &M);
|
|
|
|
// Check if we want (and can) handle this alloca.
|
|
bool isInterestingAlloca(AllocaInst &AI) {
|
|
return (!AI.isArrayAllocation() &&
|
|
AI.isStaticAlloca() &&
|
|
AI.getAllocatedType()->isSized());
|
|
}
|
|
|
|
size_t RedzoneSize() const {
|
|
return RedzoneSizeForScale(Mapping.Scale);
|
|
}
|
|
uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
|
|
Type *Ty = AI->getAllocatedType();
|
|
uint64_t SizeInBytes = ASan.TD->getTypeAllocSize(Ty);
|
|
return SizeInBytes;
|
|
}
|
|
uint64_t getAlignedSize(uint64_t SizeInBytes) {
|
|
size_t RZ = RedzoneSize();
|
|
return ((SizeInBytes + RZ - 1) / RZ) * RZ;
|
|
}
|
|
uint64_t getAlignedAllocaSize(AllocaInst *AI) {
|
|
uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
|
|
return getAlignedSize(SizeInBytes);
|
|
}
|
|
/// Finds alloca where the value comes from.
|
|
AllocaInst *findAllocaForValue(Value *V);
|
|
void poisonRedZones(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
|
|
Value *ShadowBase, bool DoPoison);
|
|
void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> IRB, bool DoPoison);
|
|
};
|
|
|
|
} // namespace
|
|
|
|
char AddressSanitizer::ID = 0;
|
|
INITIALIZE_PASS(AddressSanitizer, "asan",
|
|
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
|
|
false, false)
|
|
FunctionPass *llvm::createAddressSanitizerFunctionPass(
|
|
bool CheckInitOrder, bool CheckUseAfterReturn, bool CheckLifetime,
|
|
StringRef BlacklistFile, bool ZeroBaseShadow) {
|
|
return new AddressSanitizer(CheckInitOrder, CheckUseAfterReturn,
|
|
CheckLifetime, BlacklistFile, ZeroBaseShadow);
|
|
}
|
|
|
|
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(
|
|
bool CheckInitOrder, StringRef BlacklistFile, bool ZeroBaseShadow) {
|
|
return new AddressSanitizerModule(CheckInitOrder, BlacklistFile,
|
|
ZeroBaseShadow);
|
|
}
|
|
|
|
static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
|
|
size_t Res = CountTrailingZeros_32(TypeSize / 8);
|
|
assert(Res < kNumberOfAccessSizes);
|
|
return Res;
|
|
}
|
|
|
|
// Create a constant for Str so that we can pass it to the run-time lib.
|
|
static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
|
|
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
|
|
GlobalVariable *GV = new GlobalVariable(M, StrConst->getType(), true,
|
|
GlobalValue::PrivateLinkage, StrConst,
|
|
kAsanGenPrefix);
|
|
GV->setUnnamedAddr(true); // Ok to merge these.
|
|
GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
|
|
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));
|
|
}
|
|
|
|
void AddressSanitizer::instrumentMemIntrinsicParam(
|
|
Instruction *OrigIns,
|
|
Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
if (Size->getType() != IntptrTy)
|
|
Size = IRB.CreateIntCast(Size, IntptrTy, false);
|
|
// Check the first byte.
|
|
instrumentAddress(OrigIns, InsertBefore, Addr, 8, IsWrite, Size);
|
|
// Check the last byte.
|
|
IRB.SetInsertPoint(InsertBefore);
|
|
Value *SizeMinusOne = IRB.CreateSub(Size, ConstantInt::get(IntptrTy, 1));
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
Value *AddrLast = IRB.CreateAdd(AddrLong, SizeMinusOne);
|
|
instrumentAddress(OrigIns, InsertBefore, AddrLast, 8, IsWrite, Size);
|
|
}
|
|
|
|
// Instrument memset/memmove/memcpy
|
|
bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
|
|
Value *Dst = MI->getDest();
|
|
MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
|
|
Value *Src = MemTran ? MemTran->getSource() : 0;
|
|
Value *Length = MI->getLength();
|
|
|
|
Constant *ConstLength = dyn_cast<Constant>(Length);
|
|
Instruction *InsertBefore = MI;
|
|
if (ConstLength) {
|
|
if (ConstLength->isNullValue()) return false;
|
|
} else {
|
|
// The size is not a constant so it could be zero -- check at run-time.
|
|
IRBuilder<> IRB(InsertBefore);
|
|
|
|
Value *Cmp = IRB.CreateICmpNE(Length,
|
|
Constant::getNullValue(Length->getType()));
|
|
InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
|
|
}
|
|
|
|
instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
|
|
if (Src)
|
|
instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
|
|
return true;
|
|
}
|
|
|
|
// If I is an interesting memory access, return the PointerOperand
|
|
// and set IsWrite. Otherwise return NULL.
|
|
static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
|
|
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
|
|
if (!ClInstrumentReads) return NULL;
|
|
*IsWrite = false;
|
|
return LI->getPointerOperand();
|
|
}
|
|
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
|
|
if (!ClInstrumentWrites) return NULL;
|
|
*IsWrite = true;
|
|
return SI->getPointerOperand();
|
|
}
|
|
if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
|
|
if (!ClInstrumentAtomics) return NULL;
|
|
*IsWrite = true;
|
|
return RMW->getPointerOperand();
|
|
}
|
|
if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
|
|
if (!ClInstrumentAtomics) return NULL;
|
|
*IsWrite = true;
|
|
return XCHG->getPointerOperand();
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
void AddressSanitizer::instrumentMop(Instruction *I) {
|
|
bool IsWrite = false;
|
|
Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
|
|
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 (!CheckInitOrder)
|
|
return;
|
|
// If a global variable does not have dynamic initialization we don't
|
|
// have to instrument it. However, if a global does not have initailizer
|
|
// at all, we assume it has dynamic initializer (in other TU).
|
|
if (G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(G))
|
|
return;
|
|
}
|
|
}
|
|
|
|
Type *OrigPtrTy = Addr->getType();
|
|
Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
|
|
|
|
assert(OrigTy->isSized());
|
|
uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
|
|
|
|
assert((TypeSize % 8) == 0);
|
|
|
|
// Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check.
|
|
if (TypeSize == 8 || TypeSize == 16 ||
|
|
TypeSize == 32 || TypeSize == 64 || TypeSize == 128)
|
|
return instrumentAddress(I, I, Addr, TypeSize, IsWrite, 0);
|
|
// Instrument unusual size (but still multiple of 8).
|
|
// 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 *LastByte = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(IRB.CreatePointerCast(Addr, IntptrTy),
|
|
ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
|
|
OrigPtrTy);
|
|
Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
|
|
instrumentAddress(I, I, Addr, 8, IsWrite, Size);
|
|
instrumentAddress(I, I, LastByte, 8, IsWrite, Size);
|
|
}
|
|
|
|
// 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) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
|
|
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 AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
|
|
size_t Granularity = 1 << Mapping.Scale;
|
|
TerminatorInst *CrashTerm = 0;
|
|
|
|
if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
|
|
TerminatorInst *CheckTerm =
|
|
SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
|
|
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(cast<Instruction>(Cmp), true);
|
|
}
|
|
|
|
Instruction *Crash = generateCrashCode(
|
|
CrashTerm, AddrLong, IsWrite, AccessSizeIndex, SizeArgument);
|
|
Crash->setDebugLoc(OrigIns->getDebugLoc());
|
|
}
|
|
|
|
void AddressSanitizerModule::createInitializerPoisonCalls(
|
|
Module &M, GlobalValue *ModuleName) {
|
|
// We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
|
|
Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
|
|
// If that function is not present, this TU contains no globals, or they have
|
|
// all been optimized away
|
|
if (!GlobalInit)
|
|
return;
|
|
|
|
// 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 (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
|
|
I != E; ++I) {
|
|
if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
|
|
CallInst::Create(AsanUnpoisonGlobals, "", RI);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
|
|
Type *Ty = cast<PointerType>(G->getType())->getElementType();
|
|
DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
|
|
|
|
if (BL->isIn(*G)) 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 type linkages since other modules may be built w/o asan.
|
|
if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
|
|
G->getLinkage() != GlobalVariable::PrivateLinkage &&
|
|
G->getLinkage() != GlobalVariable::InternalLinkage)
|
|
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 Alloca if the alignment is large.
|
|
if (G->getAlignment() > RedzoneSize()) 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);
|
|
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.find("__OBJC,") == 0) ||
|
|
(Section.find("__DATA, __objc_") == 0)) {
|
|
DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
|
|
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.find("__DATA,__cfstring") == 0) {
|
|
DEBUG(dbgs() << "Ignoring CFString: " << *G);
|
|
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);
|
|
}
|
|
|
|
// 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::runOnModule(Module &M) {
|
|
if (!ClGlobals) return false;
|
|
TD = getAnalysisIfAvailable<DataLayout>();
|
|
if (!TD)
|
|
return false;
|
|
BL.reset(new BlackList(BlacklistFile));
|
|
if (BL->isIn(M)) return false;
|
|
C = &(M.getContext());
|
|
int LongSize = TD->getPointerSizeInBits();
|
|
IntptrTy = Type::getIntNTy(*C, LongSize);
|
|
Mapping = getShadowMapping(M, LongSize, ZeroBaseShadow);
|
|
initializeCallbacks(M);
|
|
DynamicallyInitializedGlobals.Init(M);
|
|
|
|
SmallVector<GlobalVariable *, 16> GlobalsToChange;
|
|
|
|
for (Module::GlobalListType::iterator G = M.global_begin(),
|
|
E = M.global_end(); G != E; ++G) {
|
|
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;
|
|
// 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, NULL);
|
|
SmallVector<Constant *, 16> Initializers(n), DynamicInit;
|
|
|
|
|
|
Function *CtorFunc = M.getFunction(kAsanModuleCtorName);
|
|
assert(CtorFunc);
|
|
IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
|
|
|
|
bool HasDynamicallyInitializedGlobals = false;
|
|
|
|
GlobalVariable *ModuleName = createPrivateGlobalForString(
|
|
M, M.getModuleIdentifier());
|
|
// We shouldn't merge same module names, as this string serves as unique
|
|
// module ID in runtime.
|
|
ModuleName->setUnnamedAddr(false);
|
|
|
|
for (size_t i = 0; i < n; i++) {
|
|
static const uint64_t kMaxGlobalRedzone = 1 << 18;
|
|
GlobalVariable *G = GlobalsToChange[i];
|
|
PointerType *PtrTy = cast<PointerType>(G->getType());
|
|
Type *Ty = PtrTy->getElementType();
|
|
uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
|
|
uint64_t MinRZ = RedzoneSize();
|
|
// 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);
|
|
// Determine whether this global should be poisoned in initialization.
|
|
bool GlobalHasDynamicInitializer =
|
|
DynamicallyInitializedGlobals.Contains(G);
|
|
// Don't check initialization order if this global is blacklisted.
|
|
GlobalHasDynamicInitializer &= !BL->isInInit(*G);
|
|
|
|
StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
|
|
Constant *NewInitializer = ConstantStruct::get(
|
|
NewTy, G->getInitializer(),
|
|
Constant::getNullValue(RightRedZoneTy), NULL);
|
|
|
|
GlobalVariable *Name = createPrivateGlobalForString(M, G->getName());
|
|
|
|
// Create a new global variable with enough space for a redzone.
|
|
GlobalVariable *NewGlobal = new GlobalVariable(
|
|
M, NewTy, G->isConstant(), G->getLinkage(),
|
|
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();
|
|
|
|
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, GlobalHasDynamicInitializer),
|
|
NULL);
|
|
|
|
// Populate the first and last globals declared in this TU.
|
|
if (CheckInitOrder && GlobalHasDynamicInitializer)
|
|
HasDynamicallyInitializedGlobals = true;
|
|
|
|
DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
|
|
}
|
|
|
|
ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
|
|
GlobalVariable *AllGlobals = new GlobalVariable(
|
|
M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
|
|
ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
|
|
|
|
// Create calls for poisoning before initializers run and unpoisoning after.
|
|
if (CheckInitOrder && 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, kAsanCtorAndCtorPriority);
|
|
|
|
DEBUG(dbgs() << M);
|
|
return true;
|
|
}
|
|
|
|
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 FunctionName = std::string(kAsanReportErrorTemplate) +
|
|
(AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
|
|
// If we are merging crash callbacks, they have two parameters.
|
|
AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
|
|
checkInterfaceFunction(M.getOrInsertFunction(
|
|
FunctionName, 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));
|
|
|
|
AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanHandleNoReturnName, IRB.getVoidTy(), 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);
|
|
}
|
|
|
|
void AddressSanitizer::emitShadowMapping(Module &M, IRBuilder<> &IRB) const {
|
|
// Tell the values of mapping offset and scale to the run-time.
|
|
GlobalValue *asan_mapping_offset =
|
|
new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
|
|
ConstantInt::get(IntptrTy, Mapping.Offset),
|
|
kAsanMappingOffsetName);
|
|
// Read the global, otherwise it may be optimized away.
|
|
IRB.CreateLoad(asan_mapping_offset, true);
|
|
|
|
GlobalValue *asan_mapping_scale =
|
|
new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
|
|
ConstantInt::get(IntptrTy, Mapping.Scale),
|
|
kAsanMappingScaleName);
|
|
// Read the global, otherwise it may be optimized away.
|
|
IRB.CreateLoad(asan_mapping_scale, true);
|
|
}
|
|
|
|
// virtual
|
|
bool AddressSanitizer::doInitialization(Module &M) {
|
|
// Initialize the private fields. No one has accessed them before.
|
|
TD = getAnalysisIfAvailable<DataLayout>();
|
|
|
|
if (!TD)
|
|
return false;
|
|
BL.reset(new BlackList(BlacklistFile));
|
|
DynamicallyInitializedGlobals.Init(M);
|
|
|
|
C = &(M.getContext());
|
|
LongSize = TD->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, ZeroBaseShadow);
|
|
emitShadowMapping(M, IRB);
|
|
|
|
appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
|
|
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;
|
|
}
|
|
|
|
bool AddressSanitizer::runOnFunction(Function &F) {
|
|
if (BL->isIn(F)) return false;
|
|
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.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
|
|
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;
|
|
bool IsWrite;
|
|
|
|
// Fill the set of memory operations to instrument.
|
|
for (Function::iterator FI = F.begin(), FE = F.end();
|
|
FI != FE; ++FI) {
|
|
TempsToInstrument.clear();
|
|
int NumInsnsPerBB = 0;
|
|
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
|
|
BI != BE; ++BI) {
|
|
if (LooksLikeCodeInBug11395(BI)) return false;
|
|
if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
|
|
if (ClOpt && ClOptSameTemp) {
|
|
if (!TempsToInstrument.insert(Addr))
|
|
continue; // We've seen this temp in the current BB.
|
|
}
|
|
} else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
|
|
// ok, take it.
|
|
} else {
|
|
CallSite CS(BI);
|
|
if (CS) {
|
|
// A call inside BB.
|
|
TempsToInstrument.clear();
|
|
if (CS.doesNotReturn())
|
|
NoReturnCalls.push_back(CS.getInstruction());
|
|
}
|
|
continue;
|
|
}
|
|
ToInstrument.push_back(BI);
|
|
NumInsnsPerBB++;
|
|
if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Instrument.
|
|
int NumInstrumented = 0;
|
|
for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
|
|
Instruction *Inst = ToInstrument[i];
|
|
if (ClDebugMin < 0 || ClDebugMax < 0 ||
|
|
(NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
|
|
if (isInterestingMemoryAccess(Inst, &IsWrite))
|
|
instrumentMop(Inst);
|
|
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 (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
|
|
Instruction *CI = NoReturnCalls[i];
|
|
IRBuilder<> IRB(CI);
|
|
IRB.CreateCall(AsanHandleNoReturnFunc);
|
|
}
|
|
DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
|
|
|
|
return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
|
|
}
|
|
|
|
static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
|
|
if (ShadowRedzoneSize == 1) return PoisonByte;
|
|
if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
|
|
if (ShadowRedzoneSize == 4)
|
|
return (PoisonByte << 24) + (PoisonByte << 16) +
|
|
(PoisonByte << 8) + (PoisonByte);
|
|
llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
|
|
}
|
|
|
|
static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
|
|
size_t Size,
|
|
size_t RZSize,
|
|
size_t ShadowGranularity,
|
|
uint8_t Magic) {
|
|
for (size_t i = 0; i < RZSize;
|
|
i+= ShadowGranularity, Shadow++) {
|
|
if (i + ShadowGranularity <= Size) {
|
|
*Shadow = 0; // fully addressable
|
|
} else if (i >= Size) {
|
|
*Shadow = Magic; // unaddressable
|
|
} else {
|
|
*Shadow = Size - i; // first Size-i bytes are addressable
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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);
|
|
AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
|
|
AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanStackFreeName, 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(
|
|
const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB, Value *ShadowBase,
|
|
bool DoPoison) {
|
|
size_t ShadowRZSize = RedzoneSize() >> Mapping.Scale;
|
|
assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
|
|
Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
|
|
Type *RZPtrTy = PointerType::get(RZTy, 0);
|
|
|
|
Value *PoisonLeft = ConstantInt::get(RZTy,
|
|
ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
|
|
Value *PoisonMid = ConstantInt::get(RZTy,
|
|
ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
|
|
Value *PoisonRight = ConstantInt::get(RZTy,
|
|
ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
|
|
|
|
// poison the first red zone.
|
|
IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
|
|
|
|
// poison all other red zones.
|
|
uint64_t Pos = RedzoneSize();
|
|
for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
|
|
AllocaInst *AI = AllocaVec[i];
|
|
uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
|
|
uint64_t AlignedSize = getAlignedAllocaSize(AI);
|
|
assert(AlignedSize - SizeInBytes < RedzoneSize());
|
|
Value *Ptr = NULL;
|
|
|
|
Pos += AlignedSize;
|
|
|
|
assert(ShadowBase->getType() == IntptrTy);
|
|
if (SizeInBytes < AlignedSize) {
|
|
// Poison the partial redzone at right
|
|
Ptr = IRB.CreateAdd(
|
|
ShadowBase, ConstantInt::get(IntptrTy,
|
|
(Pos >> Mapping.Scale) - ShadowRZSize));
|
|
size_t AddressableBytes = RedzoneSize() - (AlignedSize - SizeInBytes);
|
|
uint32_t Poison = 0;
|
|
if (DoPoison) {
|
|
PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
|
|
RedzoneSize(),
|
|
1ULL << Mapping.Scale,
|
|
kAsanStackPartialRedzoneMagic);
|
|
}
|
|
Value *PartialPoison = ConstantInt::get(RZTy, Poison);
|
|
IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
|
|
}
|
|
|
|
// Poison the full redzone at right.
|
|
Ptr = IRB.CreateAdd(ShadowBase,
|
|
ConstantInt::get(IntptrTy, Pos >> Mapping.Scale));
|
|
bool LastAlloca = (i == AllocaVec.size() - 1);
|
|
Value *Poison = LastAlloca ? PoisonRight : PoisonMid;
|
|
IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
|
|
|
|
Pos += RedzoneSize();
|
|
}
|
|
}
|
|
|
|
void FunctionStackPoisoner::poisonStack() {
|
|
uint64_t LocalStackSize = TotalStackSize +
|
|
(AllocaVec.size() + 1) * RedzoneSize();
|
|
|
|
bool DoStackMalloc = ASan.CheckUseAfterReturn
|
|
&& LocalStackSize <= kMaxStackMallocSize;
|
|
|
|
assert(AllocaVec.size() > 0);
|
|
Instruction *InsBefore = AllocaVec[0];
|
|
IRBuilder<> IRB(InsBefore);
|
|
|
|
|
|
Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
|
|
AllocaInst *MyAlloca =
|
|
new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
|
|
if (ClRealignStack && StackAlignment < RedzoneSize())
|
|
StackAlignment = RedzoneSize();
|
|
MyAlloca->setAlignment(StackAlignment);
|
|
assert(MyAlloca->isStaticAlloca());
|
|
Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
|
|
Value *LocalStackBase = OrigStackBase;
|
|
|
|
if (DoStackMalloc) {
|
|
LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
|
|
ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
|
|
}
|
|
|
|
// This string will be parsed by the run-time (DescribeAddressIfStack).
|
|
SmallString<2048> StackDescriptionStorage;
|
|
raw_svector_ostream StackDescription(StackDescriptionStorage);
|
|
StackDescription << AllocaVec.size() << " ";
|
|
|
|
// Insert poison calls for lifetime intrinsics for alloca.
|
|
bool HavePoisonedAllocas = false;
|
|
for (size_t i = 0, n = AllocaPoisonCallVec.size(); i < n; i++) {
|
|
const AllocaPoisonCall &APC = AllocaPoisonCallVec[i];
|
|
IntrinsicInst *II = APC.InsBefore;
|
|
AllocaInst *AI = findAllocaForValue(II->getArgOperand(1));
|
|
assert(AI);
|
|
IRBuilder<> IRB(II);
|
|
poisonAlloca(AI, APC.Size, IRB, APC.DoPoison);
|
|
HavePoisonedAllocas |= APC.DoPoison;
|
|
}
|
|
|
|
uint64_t Pos = RedzoneSize();
|
|
// Replace Alloca instructions with base+offset.
|
|
for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
|
|
AllocaInst *AI = AllocaVec[i];
|
|
uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
|
|
StringRef Name = AI->getName();
|
|
StackDescription << Pos << " " << SizeInBytes << " "
|
|
<< Name.size() << " " << Name << " ";
|
|
uint64_t AlignedSize = getAlignedAllocaSize(AI);
|
|
assert((AlignedSize % RedzoneSize()) == 0);
|
|
Value *NewAllocaPtr = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
|
|
AI->getType());
|
|
replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB);
|
|
AI->replaceAllUsesWith(NewAllocaPtr);
|
|
Pos += AlignedSize + RedzoneSize();
|
|
}
|
|
assert(Pos == LocalStackSize);
|
|
|
|
// 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(), StackDescription.str());
|
|
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(AllocaVec, IRB, ShadowBase, true);
|
|
|
|
// Unpoison the stack before all ret instructions.
|
|
for (size_t i = 0, n = RetVec.size(); i < n; i++) {
|
|
Instruction *Ret = RetVec[i];
|
|
IRBuilder<> IRBRet(Ret);
|
|
// Mark the current frame as retired.
|
|
IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
|
|
BasePlus0);
|
|
// Unpoison the stack.
|
|
poisonRedZones(AllocaVec, IRBRet, ShadowBase, false);
|
|
if (DoStackMalloc) {
|
|
// In use-after-return mode, mark the whole stack frame unaddressable.
|
|
IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
|
|
ConstantInt::get(IntptrTy, LocalStackSize),
|
|
OrigStackBase);
|
|
} 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);
|
|
}
|
|
}
|
|
|
|
// We are done. Remove the old unused alloca instructions.
|
|
for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
|
|
AllocaVec[i]->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 : 0;
|
|
// 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] = 0;
|
|
AllocaInst *Res = 0;
|
|
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 == 0 || (Res != 0 && IncValueAI != Res))
|
|
return 0;
|
|
Res = IncValueAI;
|
|
}
|
|
}
|
|
if (Res != 0)
|
|
AllocaForValue[V] = Res;
|
|
return Res;
|
|
}
|