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1078 lines
41 KiB
1078 lines
41 KiB
//===- MemoryBuiltins.cpp - Identify calls to memory builtins -------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This family of functions identifies calls to builtin functions that allocate
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// or free memory.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/MemoryBuiltins.h"
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#include "llvm/ADT/APInt.h"
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#include "llvm/ADT/None.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Analysis/TargetFolder.h"
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#include "llvm/Analysis/TargetLibraryInfo.h"
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#include "llvm/Analysis/Utils/Local.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/IR/Argument.h"
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#include "llvm/IR/Attributes.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalAlias.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/Instruction.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/Operator.h"
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#include "llvm/IR/Type.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Support/raw_ostream.h"
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#include <cassert>
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#include <cstdint>
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#include <iterator>
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#include <utility>
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using namespace llvm;
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#define DEBUG_TYPE "memory-builtins"
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enum AllocType : uint8_t {
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OpNewLike = 1<<0, // allocates; never returns null
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MallocLike = 1<<1 | OpNewLike, // allocates; may return null
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AlignedAllocLike = 1<<2, // allocates with alignment; may return null
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CallocLike = 1<<3, // allocates + bzero
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ReallocLike = 1<<4, // reallocates
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StrDupLike = 1<<5,
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MallocOrCallocLike = MallocLike | CallocLike | AlignedAllocLike,
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AllocLike = MallocOrCallocLike | StrDupLike,
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AnyAlloc = AllocLike | ReallocLike
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};
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struct AllocFnsTy {
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AllocType AllocTy;
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unsigned NumParams;
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// First and Second size parameters (or -1 if unused)
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int FstParam, SndParam;
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};
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// FIXME: certain users need more information. E.g., SimplifyLibCalls needs to
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// know which functions are nounwind, noalias, nocapture parameters, etc.
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static const std::pair<LibFunc, AllocFnsTy> AllocationFnData[] = {
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{LibFunc_malloc, {MallocLike, 1, 0, -1}},
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{LibFunc_valloc, {MallocLike, 1, 0, -1}},
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{LibFunc_Znwj, {OpNewLike, 1, 0, -1}}, // new(unsigned int)
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{LibFunc_ZnwjRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new(unsigned int, nothrow)
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{LibFunc_ZnwjSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new(unsigned int, align_val_t)
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{LibFunc_ZnwjSt11align_val_tRKSt9nothrow_t, // new(unsigned int, align_val_t, nothrow)
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{MallocLike, 3, 0, -1}},
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{LibFunc_Znwm, {OpNewLike, 1, 0, -1}}, // new(unsigned long)
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{LibFunc_ZnwmRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new(unsigned long, nothrow)
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{LibFunc_ZnwmSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new(unsigned long, align_val_t)
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{LibFunc_ZnwmSt11align_val_tRKSt9nothrow_t, // new(unsigned long, align_val_t, nothrow)
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{MallocLike, 3, 0, -1}},
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{LibFunc_Znaj, {OpNewLike, 1, 0, -1}}, // new[](unsigned int)
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{LibFunc_ZnajRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new[](unsigned int, nothrow)
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{LibFunc_ZnajSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new[](unsigned int, align_val_t)
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{LibFunc_ZnajSt11align_val_tRKSt9nothrow_t, // new[](unsigned int, align_val_t, nothrow)
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{MallocLike, 3, 0, -1}},
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{LibFunc_Znam, {OpNewLike, 1, 0, -1}}, // new[](unsigned long)
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{LibFunc_ZnamRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new[](unsigned long, nothrow)
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{LibFunc_ZnamSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new[](unsigned long, align_val_t)
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{LibFunc_ZnamSt11align_val_tRKSt9nothrow_t, // new[](unsigned long, align_val_t, nothrow)
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{MallocLike, 3, 0, -1}},
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{LibFunc_msvc_new_int, {OpNewLike, 1, 0, -1}}, // new(unsigned int)
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{LibFunc_msvc_new_int_nothrow, {MallocLike, 2, 0, -1}}, // new(unsigned int, nothrow)
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{LibFunc_msvc_new_longlong, {OpNewLike, 1, 0, -1}}, // new(unsigned long long)
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{LibFunc_msvc_new_longlong_nothrow, {MallocLike, 2, 0, -1}}, // new(unsigned long long, nothrow)
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{LibFunc_msvc_new_array_int, {OpNewLike, 1, 0, -1}}, // new[](unsigned int)
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{LibFunc_msvc_new_array_int_nothrow, {MallocLike, 2, 0, -1}}, // new[](unsigned int, nothrow)
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{LibFunc_msvc_new_array_longlong, {OpNewLike, 1, 0, -1}}, // new[](unsigned long long)
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{LibFunc_msvc_new_array_longlong_nothrow, {MallocLike, 2, 0, -1}}, // new[](unsigned long long, nothrow)
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{LibFunc_aligned_alloc, {AlignedAllocLike, 2, 1, -1}},
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{LibFunc_calloc, {CallocLike, 2, 0, 1}},
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{LibFunc_realloc, {ReallocLike, 2, 1, -1}},
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{LibFunc_reallocf, {ReallocLike, 2, 1, -1}},
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{LibFunc_strdup, {StrDupLike, 1, -1, -1}},
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{LibFunc_strndup, {StrDupLike, 2, 1, -1}}
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// TODO: Handle "int posix_memalign(void **, size_t, size_t)"
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};
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static const Function *getCalledFunction(const Value *V, bool LookThroughBitCast,
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bool &IsNoBuiltin) {
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// Don't care about intrinsics in this case.
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if (isa<IntrinsicInst>(V))
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return nullptr;
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if (LookThroughBitCast)
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V = V->stripPointerCasts();
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const auto *CB = dyn_cast<CallBase>(V);
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if (!CB)
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return nullptr;
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IsNoBuiltin = CB->isNoBuiltin();
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if (const Function *Callee = CB->getCalledFunction())
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return Callee;
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return nullptr;
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}
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/// Returns the allocation data for the given value if it's either a call to a
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/// known allocation function, or a call to a function with the allocsize
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/// attribute.
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static Optional<AllocFnsTy>
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getAllocationDataForFunction(const Function *Callee, AllocType AllocTy,
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const TargetLibraryInfo *TLI) {
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// Make sure that the function is available.
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StringRef FnName = Callee->getName();
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LibFunc TLIFn;
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if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
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return None;
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const auto *Iter = find_if(
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AllocationFnData, [TLIFn](const std::pair<LibFunc, AllocFnsTy> &P) {
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return P.first == TLIFn;
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});
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if (Iter == std::end(AllocationFnData))
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return None;
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const AllocFnsTy *FnData = &Iter->second;
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if ((FnData->AllocTy & AllocTy) != FnData->AllocTy)
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return None;
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// Check function prototype.
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int FstParam = FnData->FstParam;
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int SndParam = FnData->SndParam;
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FunctionType *FTy = Callee->getFunctionType();
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if (FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
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FTy->getNumParams() == FnData->NumParams &&
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(FstParam < 0 ||
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(FTy->getParamType(FstParam)->isIntegerTy(32) ||
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FTy->getParamType(FstParam)->isIntegerTy(64))) &&
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(SndParam < 0 ||
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FTy->getParamType(SndParam)->isIntegerTy(32) ||
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FTy->getParamType(SndParam)->isIntegerTy(64)))
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return *FnData;
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return None;
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}
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static Optional<AllocFnsTy> getAllocationData(const Value *V, AllocType AllocTy,
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const TargetLibraryInfo *TLI,
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bool LookThroughBitCast = false) {
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bool IsNoBuiltinCall;
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if (const Function *Callee =
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getCalledFunction(V, LookThroughBitCast, IsNoBuiltinCall))
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if (!IsNoBuiltinCall)
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return getAllocationDataForFunction(Callee, AllocTy, TLI);
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return None;
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}
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static Optional<AllocFnsTy>
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getAllocationData(const Value *V, AllocType AllocTy,
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function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
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bool LookThroughBitCast = false) {
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bool IsNoBuiltinCall;
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if (const Function *Callee =
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getCalledFunction(V, LookThroughBitCast, IsNoBuiltinCall))
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if (!IsNoBuiltinCall)
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return getAllocationDataForFunction(
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Callee, AllocTy, &GetTLI(const_cast<Function &>(*Callee)));
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return None;
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}
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static Optional<AllocFnsTy> getAllocationSize(const Value *V,
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const TargetLibraryInfo *TLI) {
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bool IsNoBuiltinCall;
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const Function *Callee =
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getCalledFunction(V, /*LookThroughBitCast=*/false, IsNoBuiltinCall);
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if (!Callee)
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return None;
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// Prefer to use existing information over allocsize. This will give us an
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// accurate AllocTy.
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if (!IsNoBuiltinCall)
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if (Optional<AllocFnsTy> Data =
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getAllocationDataForFunction(Callee, AnyAlloc, TLI))
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return Data;
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Attribute Attr = Callee->getFnAttribute(Attribute::AllocSize);
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if (Attr == Attribute())
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return None;
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std::pair<unsigned, Optional<unsigned>> Args = Attr.getAllocSizeArgs();
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AllocFnsTy Result;
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// Because allocsize only tells us how many bytes are allocated, we're not
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// really allowed to assume anything, so we use MallocLike.
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Result.AllocTy = MallocLike;
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Result.NumParams = Callee->getNumOperands();
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Result.FstParam = Args.first;
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Result.SndParam = Args.second.getValueOr(-1);
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return Result;
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}
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static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast) {
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const auto *CB =
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dyn_cast<CallBase>(LookThroughBitCast ? V->stripPointerCasts() : V);
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return CB && CB->hasRetAttr(Attribute::NoAlias);
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates or reallocates memory (either malloc, calloc, realloc, or strdup
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/// like).
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bool llvm::isAllocationFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, AnyAlloc, TLI, LookThroughBitCast).hasValue();
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}
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bool llvm::isAllocationFn(
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const Value *V, function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, AnyAlloc, GetTLI, LookThroughBitCast).hasValue();
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}
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/// Tests if a value is a call or invoke to a function that returns a
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/// NoAlias pointer (including malloc/calloc/realloc/strdup-like functions).
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bool llvm::isNoAliasFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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// it's safe to consider realloc as noalias since accessing the original
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// pointer is undefined behavior
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return isAllocationFn(V, TLI, LookThroughBitCast) ||
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hasNoAliasAttr(V, LookThroughBitCast);
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates uninitialized memory (such as malloc).
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bool llvm::isMallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, MallocLike, TLI, LookThroughBitCast).hasValue();
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}
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bool llvm::isMallocLikeFn(
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const Value *V, function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, MallocLike, GetTLI, LookThroughBitCast)
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.hasValue();
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates uninitialized memory with alignment (such as aligned_alloc).
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bool llvm::isAlignedAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, AlignedAllocLike, TLI, LookThroughBitCast)
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.hasValue();
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}
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bool llvm::isAlignedAllocLikeFn(
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const Value *V, function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, AlignedAllocLike, GetTLI, LookThroughBitCast)
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.hasValue();
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates zero-filled memory (such as calloc).
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bool llvm::isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, CallocLike, TLI, LookThroughBitCast).hasValue();
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates memory similar to malloc or calloc.
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bool llvm::isMallocOrCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, MallocOrCallocLike, TLI,
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LookThroughBitCast).hasValue();
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates memory (either malloc, calloc, or strdup like).
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bool llvm::isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, AllocLike, TLI, LookThroughBitCast).hasValue();
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}
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/// Tests if a value is a call or invoke to a library function that
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/// reallocates memory (e.g., realloc).
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bool llvm::isReallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, ReallocLike, TLI, LookThroughBitCast).hasValue();
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}
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/// Tests if a functions is a call or invoke to a library function that
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/// reallocates memory (e.g., realloc).
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bool llvm::isReallocLikeFn(const Function *F, const TargetLibraryInfo *TLI) {
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return getAllocationDataForFunction(F, ReallocLike, TLI).hasValue();
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates memory and throws if an allocation failed (e.g., new).
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bool llvm::isOpNewLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, OpNewLike, TLI, LookThroughBitCast).hasValue();
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}
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/// Tests if a value is a call or invoke to a library function that
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/// allocates memory (strdup, strndup).
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bool llvm::isStrdupLikeFn(const Value *V, const TargetLibraryInfo *TLI,
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bool LookThroughBitCast) {
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return getAllocationData(V, StrDupLike, TLI, LookThroughBitCast).hasValue();
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}
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/// extractMallocCall - Returns the corresponding CallInst if the instruction
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/// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
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/// ignore InvokeInst here.
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const CallInst *llvm::extractMallocCall(
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const Value *I,
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function_ref<const TargetLibraryInfo &(Function &)> GetTLI) {
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return isMallocLikeFn(I, GetTLI) ? dyn_cast<CallInst>(I) : nullptr;
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}
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static Value *computeArraySize(const CallInst *CI, const DataLayout &DL,
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const TargetLibraryInfo *TLI,
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bool LookThroughSExt = false) {
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if (!CI)
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return nullptr;
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// The size of the malloc's result type must be known to determine array size.
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Type *T = getMallocAllocatedType(CI, TLI);
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if (!T || !T->isSized())
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return nullptr;
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unsigned ElementSize = DL.getTypeAllocSize(T);
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if (StructType *ST = dyn_cast<StructType>(T))
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ElementSize = DL.getStructLayout(ST)->getSizeInBytes();
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// If malloc call's arg can be determined to be a multiple of ElementSize,
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// return the multiple. Otherwise, return NULL.
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Value *MallocArg = CI->getArgOperand(0);
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Value *Multiple = nullptr;
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if (ComputeMultiple(MallocArg, ElementSize, Multiple, LookThroughSExt))
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return Multiple;
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return nullptr;
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}
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/// getMallocType - Returns the PointerType resulting from the malloc call.
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/// The PointerType depends on the number of bitcast uses of the malloc call:
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/// 0: PointerType is the calls' return type.
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/// 1: PointerType is the bitcast's result type.
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/// >1: Unique PointerType cannot be determined, return NULL.
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PointerType *llvm::getMallocType(const CallInst *CI,
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const TargetLibraryInfo *TLI) {
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assert(isMallocLikeFn(CI, TLI) && "getMallocType and not malloc call");
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PointerType *MallocType = nullptr;
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unsigned NumOfBitCastUses = 0;
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// Determine if CallInst has a bitcast use.
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for (Value::const_user_iterator UI = CI->user_begin(), E = CI->user_end();
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UI != E;)
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if (const BitCastInst *BCI = dyn_cast<BitCastInst>(*UI++)) {
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MallocType = cast<PointerType>(BCI->getDestTy());
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NumOfBitCastUses++;
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}
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// Malloc call has 1 bitcast use, so type is the bitcast's destination type.
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if (NumOfBitCastUses == 1)
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return MallocType;
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// Malloc call was not bitcast, so type is the malloc function's return type.
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if (NumOfBitCastUses == 0)
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return cast<PointerType>(CI->getType());
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// Type could not be determined.
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return nullptr;
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}
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/// getMallocAllocatedType - Returns the Type allocated by malloc call.
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/// The Type depends on the number of bitcast uses of the malloc call:
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/// 0: PointerType is the malloc calls' return type.
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/// 1: PointerType is the bitcast's result type.
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/// >1: Unique PointerType cannot be determined, return NULL.
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Type *llvm::getMallocAllocatedType(const CallInst *CI,
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const TargetLibraryInfo *TLI) {
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PointerType *PT = getMallocType(CI, TLI);
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return PT ? PT->getElementType() : nullptr;
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}
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/// getMallocArraySize - Returns the array size of a malloc call. If the
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/// argument passed to malloc is a multiple of the size of the malloced type,
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/// then return that multiple. For non-array mallocs, the multiple is
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/// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
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/// determined.
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Value *llvm::getMallocArraySize(CallInst *CI, const DataLayout &DL,
|
|
const TargetLibraryInfo *TLI,
|
|
bool LookThroughSExt) {
|
|
assert(isMallocLikeFn(CI, TLI) && "getMallocArraySize and not malloc call");
|
|
return computeArraySize(CI, DL, TLI, LookThroughSExt);
|
|
}
|
|
|
|
/// extractCallocCall - Returns the corresponding CallInst if the instruction
|
|
/// is a calloc call.
|
|
const CallInst *llvm::extractCallocCall(const Value *I,
|
|
const TargetLibraryInfo *TLI) {
|
|
return isCallocLikeFn(I, TLI) ? cast<CallInst>(I) : nullptr;
|
|
}
|
|
|
|
/// isLibFreeFunction - Returns true if the function is a builtin free()
|
|
bool llvm::isLibFreeFunction(const Function *F, const LibFunc TLIFn) {
|
|
unsigned ExpectedNumParams;
|
|
if (TLIFn == LibFunc_free ||
|
|
TLIFn == LibFunc_ZdlPv || // operator delete(void*)
|
|
TLIFn == LibFunc_ZdaPv || // operator delete[](void*)
|
|
TLIFn == LibFunc_msvc_delete_ptr32 || // operator delete(void*)
|
|
TLIFn == LibFunc_msvc_delete_ptr64 || // operator delete(void*)
|
|
TLIFn == LibFunc_msvc_delete_array_ptr32 || // operator delete[](void*)
|
|
TLIFn == LibFunc_msvc_delete_array_ptr64) // operator delete[](void*)
|
|
ExpectedNumParams = 1;
|
|
else if (TLIFn == LibFunc_ZdlPvj || // delete(void*, uint)
|
|
TLIFn == LibFunc_ZdlPvm || // delete(void*, ulong)
|
|
TLIFn == LibFunc_ZdlPvRKSt9nothrow_t || // delete(void*, nothrow)
|
|
TLIFn == LibFunc_ZdlPvSt11align_val_t || // delete(void*, align_val_t)
|
|
TLIFn == LibFunc_ZdaPvj || // delete[](void*, uint)
|
|
TLIFn == LibFunc_ZdaPvm || // delete[](void*, ulong)
|
|
TLIFn == LibFunc_ZdaPvRKSt9nothrow_t || // delete[](void*, nothrow)
|
|
TLIFn == LibFunc_ZdaPvSt11align_val_t || // delete[](void*, align_val_t)
|
|
TLIFn == LibFunc_msvc_delete_ptr32_int || // delete(void*, uint)
|
|
TLIFn == LibFunc_msvc_delete_ptr64_longlong || // delete(void*, ulonglong)
|
|
TLIFn == LibFunc_msvc_delete_ptr32_nothrow || // delete(void*, nothrow)
|
|
TLIFn == LibFunc_msvc_delete_ptr64_nothrow || // delete(void*, nothrow)
|
|
TLIFn == LibFunc_msvc_delete_array_ptr32_int || // delete[](void*, uint)
|
|
TLIFn == LibFunc_msvc_delete_array_ptr64_longlong || // delete[](void*, ulonglong)
|
|
TLIFn == LibFunc_msvc_delete_array_ptr32_nothrow || // delete[](void*, nothrow)
|
|
TLIFn == LibFunc_msvc_delete_array_ptr64_nothrow) // delete[](void*, nothrow)
|
|
ExpectedNumParams = 2;
|
|
else if (TLIFn == LibFunc_ZdaPvSt11align_val_tRKSt9nothrow_t || // delete(void*, align_val_t, nothrow)
|
|
TLIFn == LibFunc_ZdlPvSt11align_val_tRKSt9nothrow_t || // delete[](void*, align_val_t, nothrow)
|
|
TLIFn == LibFunc_ZdlPvjSt11align_val_t || // delete(void*, unsigned long, align_val_t)
|
|
TLIFn == LibFunc_ZdlPvmSt11align_val_t || // delete(void*, unsigned long, align_val_t)
|
|
TLIFn == LibFunc_ZdaPvjSt11align_val_t || // delete[](void*, unsigned int, align_val_t)
|
|
TLIFn == LibFunc_ZdaPvmSt11align_val_t) // delete[](void*, unsigned long, align_val_t)
|
|
ExpectedNumParams = 3;
|
|
else
|
|
return false;
|
|
|
|
// Check free prototype.
|
|
// FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
|
|
// attribute will exist.
|
|
FunctionType *FTy = F->getFunctionType();
|
|
if (!FTy->getReturnType()->isVoidTy())
|
|
return false;
|
|
if (FTy->getNumParams() != ExpectedNumParams)
|
|
return false;
|
|
if (FTy->getParamType(0) != Type::getInt8PtrTy(F->getContext()))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/// isFreeCall - Returns non-null if the value is a call to the builtin free()
|
|
const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
|
|
bool IsNoBuiltinCall;
|
|
const Function *Callee =
|
|
getCalledFunction(I, /*LookThroughBitCast=*/false, IsNoBuiltinCall);
|
|
if (Callee == nullptr || IsNoBuiltinCall)
|
|
return nullptr;
|
|
|
|
StringRef FnName = Callee->getName();
|
|
LibFunc TLIFn;
|
|
if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
|
|
return nullptr;
|
|
|
|
return isLibFreeFunction(Callee, TLIFn) ? dyn_cast<CallInst>(I) : nullptr;
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Utility functions to compute size of objects.
|
|
//
|
|
static APInt getSizeWithOverflow(const SizeOffsetType &Data) {
|
|
if (Data.second.isNegative() || Data.first.ult(Data.second))
|
|
return APInt(Data.first.getBitWidth(), 0);
|
|
return Data.first - Data.second;
|
|
}
|
|
|
|
/// Compute the size of the object pointed by Ptr. Returns true and the
|
|
/// object size in Size if successful, and false otherwise.
|
|
/// If RoundToAlign is true, then Size is rounded up to the alignment of
|
|
/// allocas, byval arguments, and global variables.
|
|
bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
|
|
const TargetLibraryInfo *TLI, ObjectSizeOpts Opts) {
|
|
ObjectSizeOffsetVisitor Visitor(DL, TLI, Ptr->getContext(), Opts);
|
|
SizeOffsetType Data = Visitor.compute(const_cast<Value*>(Ptr));
|
|
if (!Visitor.bothKnown(Data))
|
|
return false;
|
|
|
|
Size = getSizeWithOverflow(Data).getZExtValue();
|
|
return true;
|
|
}
|
|
|
|
Value *llvm::lowerObjectSizeCall(IntrinsicInst *ObjectSize,
|
|
const DataLayout &DL,
|
|
const TargetLibraryInfo *TLI,
|
|
bool MustSucceed) {
|
|
assert(ObjectSize->getIntrinsicID() == Intrinsic::objectsize &&
|
|
"ObjectSize must be a call to llvm.objectsize!");
|
|
|
|
bool MaxVal = cast<ConstantInt>(ObjectSize->getArgOperand(1))->isZero();
|
|
ObjectSizeOpts EvalOptions;
|
|
// Unless we have to fold this to something, try to be as accurate as
|
|
// possible.
|
|
if (MustSucceed)
|
|
EvalOptions.EvalMode =
|
|
MaxVal ? ObjectSizeOpts::Mode::Max : ObjectSizeOpts::Mode::Min;
|
|
else
|
|
EvalOptions.EvalMode = ObjectSizeOpts::Mode::Exact;
|
|
|
|
EvalOptions.NullIsUnknownSize =
|
|
cast<ConstantInt>(ObjectSize->getArgOperand(2))->isOne();
|
|
|
|
auto *ResultType = cast<IntegerType>(ObjectSize->getType());
|
|
bool StaticOnly = cast<ConstantInt>(ObjectSize->getArgOperand(3))->isZero();
|
|
if (StaticOnly) {
|
|
// FIXME: Does it make sense to just return a failure value if the size won't
|
|
// fit in the output and `!MustSucceed`?
|
|
uint64_t Size;
|
|
if (getObjectSize(ObjectSize->getArgOperand(0), Size, DL, TLI, EvalOptions) &&
|
|
isUIntN(ResultType->getBitWidth(), Size))
|
|
return ConstantInt::get(ResultType, Size);
|
|
} else {
|
|
LLVMContext &Ctx = ObjectSize->getFunction()->getContext();
|
|
ObjectSizeOffsetEvaluator Eval(DL, TLI, Ctx, EvalOptions);
|
|
SizeOffsetEvalType SizeOffsetPair =
|
|
Eval.compute(ObjectSize->getArgOperand(0));
|
|
|
|
if (SizeOffsetPair != ObjectSizeOffsetEvaluator::unknown()) {
|
|
IRBuilder<TargetFolder> Builder(Ctx, TargetFolder(DL));
|
|
Builder.SetInsertPoint(ObjectSize);
|
|
|
|
// If we've outside the end of the object, then we can always access
|
|
// exactly 0 bytes.
|
|
Value *ResultSize =
|
|
Builder.CreateSub(SizeOffsetPair.first, SizeOffsetPair.second);
|
|
Value *UseZero =
|
|
Builder.CreateICmpULT(SizeOffsetPair.first, SizeOffsetPair.second);
|
|
ResultSize = Builder.CreateZExtOrTrunc(ResultSize, ResultType);
|
|
return Builder.CreateSelect(UseZero, ConstantInt::get(ResultType, 0),
|
|
ResultSize);
|
|
}
|
|
}
|
|
|
|
if (!MustSucceed)
|
|
return nullptr;
|
|
|
|
return ConstantInt::get(ResultType, MaxVal ? -1ULL : 0);
|
|
}
|
|
|
|
STATISTIC(ObjectVisitorArgument,
|
|
"Number of arguments with unsolved size and offset");
|
|
STATISTIC(ObjectVisitorLoad,
|
|
"Number of load instructions with unsolved size and offset");
|
|
|
|
APInt ObjectSizeOffsetVisitor::align(APInt Size, uint64_t Alignment) {
|
|
if (Options.RoundToAlign && Alignment)
|
|
return APInt(IntTyBits, alignTo(Size.getZExtValue(), Align(Alignment)));
|
|
return Size;
|
|
}
|
|
|
|
ObjectSizeOffsetVisitor::ObjectSizeOffsetVisitor(const DataLayout &DL,
|
|
const TargetLibraryInfo *TLI,
|
|
LLVMContext &Context,
|
|
ObjectSizeOpts Options)
|
|
: DL(DL), TLI(TLI), Options(Options) {
|
|
// Pointer size must be rechecked for each object visited since it could have
|
|
// a different address space.
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
|
|
IntTyBits = DL.getIndexTypeSizeInBits(V->getType());
|
|
Zero = APInt::getNullValue(IntTyBits);
|
|
|
|
V = V->stripPointerCasts();
|
|
if (Instruction *I = dyn_cast<Instruction>(V)) {
|
|
// If we have already seen this instruction, bail out. Cycles can happen in
|
|
// unreachable code after constant propagation.
|
|
if (!SeenInsts.insert(I).second)
|
|
return unknown();
|
|
|
|
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
|
|
return visitGEPOperator(*GEP);
|
|
return visit(*I);
|
|
}
|
|
if (Argument *A = dyn_cast<Argument>(V))
|
|
return visitArgument(*A);
|
|
if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
|
|
return visitConstantPointerNull(*P);
|
|
if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
|
|
return visitGlobalAlias(*GA);
|
|
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
|
|
return visitGlobalVariable(*GV);
|
|
if (UndefValue *UV = dyn_cast<UndefValue>(V))
|
|
return visitUndefValue(*UV);
|
|
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
|
|
if (CE->getOpcode() == Instruction::IntToPtr)
|
|
return unknown(); // clueless
|
|
if (CE->getOpcode() == Instruction::GetElementPtr)
|
|
return visitGEPOperator(cast<GEPOperator>(*CE));
|
|
}
|
|
|
|
LLVM_DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: "
|
|
<< *V << '\n');
|
|
return unknown();
|
|
}
|
|
|
|
/// When we're compiling N-bit code, and the user uses parameters that are
|
|
/// greater than N bits (e.g. uint64_t on a 32-bit build), we can run into
|
|
/// trouble with APInt size issues. This function handles resizing + overflow
|
|
/// checks for us. Check and zext or trunc \p I depending on IntTyBits and
|
|
/// I's value.
|
|
bool ObjectSizeOffsetVisitor::CheckedZextOrTrunc(APInt &I) {
|
|
// More bits than we can handle. Checking the bit width isn't necessary, but
|
|
// it's faster than checking active bits, and should give `false` in the
|
|
// vast majority of cases.
|
|
if (I.getBitWidth() > IntTyBits && I.getActiveBits() > IntTyBits)
|
|
return false;
|
|
if (I.getBitWidth() != IntTyBits)
|
|
I = I.zextOrTrunc(IntTyBits);
|
|
return true;
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitAllocaInst(AllocaInst &I) {
|
|
if (!I.getAllocatedType()->isSized())
|
|
return unknown();
|
|
|
|
if (isa<ScalableVectorType>(I.getAllocatedType()))
|
|
return unknown();
|
|
|
|
APInt Size(IntTyBits, DL.getTypeAllocSize(I.getAllocatedType()));
|
|
if (!I.isArrayAllocation())
|
|
return std::make_pair(align(Size, I.getAlignment()), Zero);
|
|
|
|
Value *ArraySize = I.getArraySize();
|
|
if (const ConstantInt *C = dyn_cast<ConstantInt>(ArraySize)) {
|
|
APInt NumElems = C->getValue();
|
|
if (!CheckedZextOrTrunc(NumElems))
|
|
return unknown();
|
|
|
|
bool Overflow;
|
|
Size = Size.umul_ov(NumElems, Overflow);
|
|
return Overflow ? unknown() : std::make_pair(align(Size, I.getAlignment()),
|
|
Zero);
|
|
}
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitArgument(Argument &A) {
|
|
Type *MemoryTy = A.getPointeeInMemoryValueType();
|
|
// No interprocedural analysis is done at the moment.
|
|
if (!MemoryTy|| !MemoryTy->isSized()) {
|
|
++ObjectVisitorArgument;
|
|
return unknown();
|
|
}
|
|
|
|
APInt Size(IntTyBits, DL.getTypeAllocSize(MemoryTy));
|
|
return std::make_pair(align(Size, A.getParamAlignment()), Zero);
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitCallBase(CallBase &CB) {
|
|
Optional<AllocFnsTy> FnData = getAllocationSize(&CB, TLI);
|
|
if (!FnData)
|
|
return unknown();
|
|
|
|
// Handle strdup-like functions separately.
|
|
if (FnData->AllocTy == StrDupLike) {
|
|
APInt Size(IntTyBits, GetStringLength(CB.getArgOperand(0)));
|
|
if (!Size)
|
|
return unknown();
|
|
|
|
// Strndup limits strlen.
|
|
if (FnData->FstParam > 0) {
|
|
ConstantInt *Arg =
|
|
dyn_cast<ConstantInt>(CB.getArgOperand(FnData->FstParam));
|
|
if (!Arg)
|
|
return unknown();
|
|
|
|
APInt MaxSize = Arg->getValue().zextOrSelf(IntTyBits);
|
|
if (Size.ugt(MaxSize))
|
|
Size = MaxSize + 1;
|
|
}
|
|
return std::make_pair(Size, Zero);
|
|
}
|
|
|
|
ConstantInt *Arg = dyn_cast<ConstantInt>(CB.getArgOperand(FnData->FstParam));
|
|
if (!Arg)
|
|
return unknown();
|
|
|
|
APInt Size = Arg->getValue();
|
|
if (!CheckedZextOrTrunc(Size))
|
|
return unknown();
|
|
|
|
// Size is determined by just 1 parameter.
|
|
if (FnData->SndParam < 0)
|
|
return std::make_pair(Size, Zero);
|
|
|
|
Arg = dyn_cast<ConstantInt>(CB.getArgOperand(FnData->SndParam));
|
|
if (!Arg)
|
|
return unknown();
|
|
|
|
APInt NumElems = Arg->getValue();
|
|
if (!CheckedZextOrTrunc(NumElems))
|
|
return unknown();
|
|
|
|
bool Overflow;
|
|
Size = Size.umul_ov(NumElems, Overflow);
|
|
return Overflow ? unknown() : std::make_pair(Size, Zero);
|
|
|
|
// TODO: handle more standard functions (+ wchar cousins):
|
|
// - strdup / strndup
|
|
// - strcpy / strncpy
|
|
// - strcat / strncat
|
|
// - memcpy / memmove
|
|
// - strcat / strncat
|
|
// - memset
|
|
}
|
|
|
|
SizeOffsetType
|
|
ObjectSizeOffsetVisitor::visitConstantPointerNull(ConstantPointerNull& CPN) {
|
|
// If null is unknown, there's nothing we can do. Additionally, non-zero
|
|
// address spaces can make use of null, so we don't presume to know anything
|
|
// about that.
|
|
//
|
|
// TODO: How should this work with address space casts? We currently just drop
|
|
// them on the floor, but it's unclear what we should do when a NULL from
|
|
// addrspace(1) gets casted to addrspace(0) (or vice-versa).
|
|
if (Options.NullIsUnknownSize || CPN.getType()->getAddressSpace())
|
|
return unknown();
|
|
return std::make_pair(Zero, Zero);
|
|
}
|
|
|
|
SizeOffsetType
|
|
ObjectSizeOffsetVisitor::visitExtractElementInst(ExtractElementInst&) {
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetType
|
|
ObjectSizeOffsetVisitor::visitExtractValueInst(ExtractValueInst&) {
|
|
// Easy cases were already folded by previous passes.
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
|
|
SizeOffsetType PtrData = compute(GEP.getPointerOperand());
|
|
APInt Offset(DL.getIndexTypeSizeInBits(GEP.getPointerOperand()->getType()), 0);
|
|
if (!bothKnown(PtrData) || !GEP.accumulateConstantOffset(DL, Offset))
|
|
return unknown();
|
|
|
|
return std::make_pair(PtrData.first, PtrData.second + Offset);
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalAlias(GlobalAlias &GA) {
|
|
if (GA.isInterposable())
|
|
return unknown();
|
|
return compute(GA.getAliasee());
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
|
|
if (!GV.hasDefinitiveInitializer())
|
|
return unknown();
|
|
|
|
APInt Size(IntTyBits, DL.getTypeAllocSize(GV.getValueType()));
|
|
return std::make_pair(align(Size, GV.getAlignment()), Zero);
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitIntToPtrInst(IntToPtrInst&) {
|
|
// clueless
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitLoadInst(LoadInst&) {
|
|
++ObjectVisitorLoad;
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
|
|
// too complex to analyze statically.
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
|
|
SizeOffsetType TrueSide = compute(I.getTrueValue());
|
|
SizeOffsetType FalseSide = compute(I.getFalseValue());
|
|
if (bothKnown(TrueSide) && bothKnown(FalseSide)) {
|
|
if (TrueSide == FalseSide) {
|
|
return TrueSide;
|
|
}
|
|
|
|
APInt TrueResult = getSizeWithOverflow(TrueSide);
|
|
APInt FalseResult = getSizeWithOverflow(FalseSide);
|
|
|
|
if (TrueResult == FalseResult) {
|
|
return TrueSide;
|
|
}
|
|
if (Options.EvalMode == ObjectSizeOpts::Mode::Min) {
|
|
if (TrueResult.slt(FalseResult))
|
|
return TrueSide;
|
|
return FalseSide;
|
|
}
|
|
if (Options.EvalMode == ObjectSizeOpts::Mode::Max) {
|
|
if (TrueResult.sgt(FalseResult))
|
|
return TrueSide;
|
|
return FalseSide;
|
|
}
|
|
}
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitUndefValue(UndefValue&) {
|
|
return std::make_pair(Zero, Zero);
|
|
}
|
|
|
|
SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
|
|
LLVM_DEBUG(dbgs() << "ObjectSizeOffsetVisitor unknown instruction:" << I
|
|
<< '\n');
|
|
return unknown();
|
|
}
|
|
|
|
ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(
|
|
const DataLayout &DL, const TargetLibraryInfo *TLI, LLVMContext &Context,
|
|
ObjectSizeOpts EvalOpts)
|
|
: DL(DL), TLI(TLI), Context(Context),
|
|
Builder(Context, TargetFolder(DL),
|
|
IRBuilderCallbackInserter(
|
|
[&](Instruction *I) { InsertedInstructions.insert(I); })),
|
|
EvalOpts(EvalOpts) {
|
|
// IntTy and Zero must be set for each compute() since the address space may
|
|
// be different for later objects.
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
|
|
// XXX - Are vectors of pointers possible here?
|
|
IntTy = cast<IntegerType>(DL.getIndexType(V->getType()));
|
|
Zero = ConstantInt::get(IntTy, 0);
|
|
|
|
SizeOffsetEvalType Result = compute_(V);
|
|
|
|
if (!bothKnown(Result)) {
|
|
// Erase everything that was computed in this iteration from the cache, so
|
|
// that no dangling references are left behind. We could be a bit smarter if
|
|
// we kept a dependency graph. It's probably not worth the complexity.
|
|
for (const Value *SeenVal : SeenVals) {
|
|
CacheMapTy::iterator CacheIt = CacheMap.find(SeenVal);
|
|
// non-computable results can be safely cached
|
|
if (CacheIt != CacheMap.end() && anyKnown(CacheIt->second))
|
|
CacheMap.erase(CacheIt);
|
|
}
|
|
|
|
// Erase any instructions we inserted as part of the traversal.
|
|
for (Instruction *I : InsertedInstructions) {
|
|
I->replaceAllUsesWith(UndefValue::get(I->getType()));
|
|
I->eraseFromParent();
|
|
}
|
|
}
|
|
|
|
SeenVals.clear();
|
|
InsertedInstructions.clear();
|
|
return Result;
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
|
|
ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, EvalOpts);
|
|
SizeOffsetType Const = Visitor.compute(V);
|
|
if (Visitor.bothKnown(Const))
|
|
return std::make_pair(ConstantInt::get(Context, Const.first),
|
|
ConstantInt::get(Context, Const.second));
|
|
|
|
V = V->stripPointerCasts();
|
|
|
|
// Check cache.
|
|
CacheMapTy::iterator CacheIt = CacheMap.find(V);
|
|
if (CacheIt != CacheMap.end())
|
|
return CacheIt->second;
|
|
|
|
// Always generate code immediately before the instruction being
|
|
// processed, so that the generated code dominates the same BBs.
|
|
BuilderTy::InsertPointGuard Guard(Builder);
|
|
if (Instruction *I = dyn_cast<Instruction>(V))
|
|
Builder.SetInsertPoint(I);
|
|
|
|
// Now compute the size and offset.
|
|
SizeOffsetEvalType Result;
|
|
|
|
// Record the pointers that were handled in this run, so that they can be
|
|
// cleaned later if something fails. We also use this set to break cycles that
|
|
// can occur in dead code.
|
|
if (!SeenVals.insert(V).second) {
|
|
Result = unknown();
|
|
} else if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
|
|
Result = visitGEPOperator(*GEP);
|
|
} else if (Instruction *I = dyn_cast<Instruction>(V)) {
|
|
Result = visit(*I);
|
|
} else if (isa<Argument>(V) ||
|
|
(isa<ConstantExpr>(V) &&
|
|
cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
|
|
isa<GlobalAlias>(V) ||
|
|
isa<GlobalVariable>(V)) {
|
|
// Ignore values where we cannot do more than ObjectSizeVisitor.
|
|
Result = unknown();
|
|
} else {
|
|
LLVM_DEBUG(
|
|
dbgs() << "ObjectSizeOffsetEvaluator::compute() unhandled value: " << *V
|
|
<< '\n');
|
|
Result = unknown();
|
|
}
|
|
|
|
// Don't reuse CacheIt since it may be invalid at this point.
|
|
CacheMap[V] = Result;
|
|
return Result;
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitAllocaInst(AllocaInst &I) {
|
|
if (!I.getAllocatedType()->isSized())
|
|
return unknown();
|
|
|
|
// must be a VLA
|
|
assert(I.isArrayAllocation());
|
|
Value *ArraySize = I.getArraySize();
|
|
Value *Size = ConstantInt::get(ArraySize->getType(),
|
|
DL.getTypeAllocSize(I.getAllocatedType()));
|
|
Size = Builder.CreateMul(Size, ArraySize);
|
|
return std::make_pair(Size, Zero);
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallBase(CallBase &CB) {
|
|
Optional<AllocFnsTy> FnData = getAllocationSize(&CB, TLI);
|
|
if (!FnData)
|
|
return unknown();
|
|
|
|
// Handle strdup-like functions separately.
|
|
if (FnData->AllocTy == StrDupLike) {
|
|
// TODO
|
|
return unknown();
|
|
}
|
|
|
|
Value *FirstArg = CB.getArgOperand(FnData->FstParam);
|
|
FirstArg = Builder.CreateZExtOrTrunc(FirstArg, IntTy);
|
|
if (FnData->SndParam < 0)
|
|
return std::make_pair(FirstArg, Zero);
|
|
|
|
Value *SecondArg = CB.getArgOperand(FnData->SndParam);
|
|
SecondArg = Builder.CreateZExtOrTrunc(SecondArg, IntTy);
|
|
Value *Size = Builder.CreateMul(FirstArg, SecondArg);
|
|
return std::make_pair(Size, Zero);
|
|
|
|
// TODO: handle more standard functions (+ wchar cousins):
|
|
// - strdup / strndup
|
|
// - strcpy / strncpy
|
|
// - strcat / strncat
|
|
// - memcpy / memmove
|
|
// - strcat / strncat
|
|
// - memset
|
|
}
|
|
|
|
SizeOffsetEvalType
|
|
ObjectSizeOffsetEvaluator::visitExtractElementInst(ExtractElementInst&) {
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetEvalType
|
|
ObjectSizeOffsetEvaluator::visitExtractValueInst(ExtractValueInst&) {
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetEvalType
|
|
ObjectSizeOffsetEvaluator::visitGEPOperator(GEPOperator &GEP) {
|
|
SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
|
|
if (!bothKnown(PtrData))
|
|
return unknown();
|
|
|
|
Value *Offset = EmitGEPOffset(&Builder, DL, &GEP, /*NoAssumptions=*/true);
|
|
Offset = Builder.CreateAdd(PtrData.second, Offset);
|
|
return std::make_pair(PtrData.first, Offset);
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitIntToPtrInst(IntToPtrInst&) {
|
|
// clueless
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitLoadInst(LoadInst&) {
|
|
return unknown();
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitPHINode(PHINode &PHI) {
|
|
// Create 2 PHIs: one for size and another for offset.
|
|
PHINode *SizePHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
|
|
PHINode *OffsetPHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
|
|
|
|
// Insert right away in the cache to handle recursive PHIs.
|
|
CacheMap[&PHI] = std::make_pair(SizePHI, OffsetPHI);
|
|
|
|
// Compute offset/size for each PHI incoming pointer.
|
|
for (unsigned i = 0, e = PHI.getNumIncomingValues(); i != e; ++i) {
|
|
Builder.SetInsertPoint(&*PHI.getIncomingBlock(i)->getFirstInsertionPt());
|
|
SizeOffsetEvalType EdgeData = compute_(PHI.getIncomingValue(i));
|
|
|
|
if (!bothKnown(EdgeData)) {
|
|
OffsetPHI->replaceAllUsesWith(UndefValue::get(IntTy));
|
|
OffsetPHI->eraseFromParent();
|
|
InsertedInstructions.erase(OffsetPHI);
|
|
SizePHI->replaceAllUsesWith(UndefValue::get(IntTy));
|
|
SizePHI->eraseFromParent();
|
|
InsertedInstructions.erase(SizePHI);
|
|
return unknown();
|
|
}
|
|
SizePHI->addIncoming(EdgeData.first, PHI.getIncomingBlock(i));
|
|
OffsetPHI->addIncoming(EdgeData.second, PHI.getIncomingBlock(i));
|
|
}
|
|
|
|
Value *Size = SizePHI, *Offset = OffsetPHI;
|
|
if (Value *Tmp = SizePHI->hasConstantValue()) {
|
|
Size = Tmp;
|
|
SizePHI->replaceAllUsesWith(Size);
|
|
SizePHI->eraseFromParent();
|
|
InsertedInstructions.erase(SizePHI);
|
|
}
|
|
if (Value *Tmp = OffsetPHI->hasConstantValue()) {
|
|
Offset = Tmp;
|
|
OffsetPHI->replaceAllUsesWith(Offset);
|
|
OffsetPHI->eraseFromParent();
|
|
InsertedInstructions.erase(OffsetPHI);
|
|
}
|
|
return std::make_pair(Size, Offset);
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
|
|
SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
|
|
SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
|
|
|
|
if (!bothKnown(TrueSide) || !bothKnown(FalseSide))
|
|
return unknown();
|
|
if (TrueSide == FalseSide)
|
|
return TrueSide;
|
|
|
|
Value *Size = Builder.CreateSelect(I.getCondition(), TrueSide.first,
|
|
FalseSide.first);
|
|
Value *Offset = Builder.CreateSelect(I.getCondition(), TrueSide.second,
|
|
FalseSide.second);
|
|
return std::make_pair(Size, Offset);
|
|
}
|
|
|
|
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitInstruction(Instruction &I) {
|
|
LLVM_DEBUG(dbgs() << "ObjectSizeOffsetEvaluator unknown instruction:" << I
|
|
<< '\n');
|
|
return unknown();
|
|
}
|