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f5a950ad26d5b30a40259a13deec98e30f08a743
revng-revng/variablemanager.cpp
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Alessandro Di Federico f5a950ad26 Move assertModuleIsMaterialized to debug.cpp
2017-08-12 11:28:07 +02:00

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/// \file variablemanager.cpp
/// \brief This file handles the creation and management of global variables,
/// i.e. mainly parts of the CPU state
//
// This file is distributed under the MIT License. See LICENSE.md for details.
//
// Standard includes
#include <cstdint>
#include <stack>
#include <sstream>
#include <set>
#include <string>
// LLVM includes
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Casting.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
// Local includes
#include "debug.h"
#include "ir-helpers.h"
#include "variablemanager.h"
#include "revamb.h"
#include "ptcdump.h"
#include "ptcinterface.h"
using namespace llvm;
class OffsetValueStack {
private:
using OffsetValuePair = std::pair<int64_t, Value *>;
public:
void pushIfNew(int64_t Offset, Value *V) {
OffsetValuePair Element = { Offset, V };
if (!Seen.count(Element)) {
Seen.insert(Element);
Stack.push_back(Element);
}
}
void push(int64_t Offset, Value *V) {
OffsetValuePair Element = { Offset, V };
Stack.push_back(Element);
}
bool empty() { return Stack.empty(); }
std::pair<int64_t, Value *> pop() {
auto Result = Stack.back();
Stack.pop_back();
return Result;
}
// TODO: this is on O(n)
void cloneSisters(Value *Old, Value *New) {
for (auto &OVP : Stack)
if (OVP.second == Old)
push(OVP.first, New);
}
private:
std::set<OffsetValuePair> Seen;
std::vector<OffsetValuePair> Stack;
};
static const int64_t ErrorOffset = std::numeric_limits<int64_t>::max();
bool CorrectCPUStateUsagePass::runOnModule(Module& TheModule) {
OffsetValueStack WorkList;
Value *CPUStatePtr = TheModule.getGlobalVariable("env");
// Do we even have "env"?
if (CPUStatePtr == nullptr)
return false;
assert(CPUStatePtr->getType()->isPointerTy());
struct Specialization {
Function *F;
Function *Original;
std::vector<std::pair<unsigned, int64_t>> SpecializedArgs;
};
std::vector<Specialization> Specializations;
std::map<Function *, int64_t> OffsetFunctions;
const DataLayout& DL = TheModule.getDataLayout();
while (true) {
if (WorkList.empty()) {
for (Use& CPUStateUse : CPUStatePtr->uses()) {
auto *Load = cast<LoadInst>(CPUStateUse.getUser());
assert(Load->getPointerOperand() == CPUStatePtr);
WorkList.pushIfNew(Variables->EnvOffset, Load);
}
}
if (WorkList.empty())
break;
int64_t CurrentOffset;
Value *CurrentValue;
std::tie(CurrentOffset, CurrentValue) = WorkList.pop();
std::vector<std::tuple<User *, Value *, Value *>> Replacements;
for (Use& TheUse : CurrentValue->uses()) {
Instruction *TheUser = cast<Instruction>(TheUse.getUser());
auto Opcode = TheUser->getOpcode();
if (CurrentOffset == ErrorOffset
&& Opcode != Instruction::Load
&& Opcode != Instruction::Store) {
// Not loading or storing, propagate the error value
WorkList.push(ErrorOffset, TheUser);
continue;
}
switch(Opcode) {
case Instruction::Load:
case Instruction::Store:
{
auto *Load = dyn_cast<LoadInst>(TheUser);
auto *Store = dyn_cast<StoreInst>(TheUser);
IRBuilder<> Builder(cast<Instruction>(TheUser));
bool Success = false;
if (Load != nullptr) {
unsigned Size = DL.getTypeSizeInBits(TheUser->getType()) / 8;
assert(Size != 0);
unsigned CurrentEnvOffset = CurrentOffset - EnvOffset;
auto *Loaded = Variables->loadFromEnvOffset(Builder,
Size,
CurrentEnvOffset);
Success = Loaded != nullptr;
if (Success)
TheUser->replaceAllUsesWith(Loaded);
} else {
Value *ToStore = Store->getValueOperand();
unsigned Size = DL.getTypeSizeInBits(ToStore->getType()) / 8;
assert(Size != 0);
unsigned CurrentEnvOffset = CurrentOffset - EnvOffset;
Success = Variables->storeToEnvOffset(Builder,
Size,
CurrentEnvOffset,
ToStore);
}
if (Success)
Replacements.push_back(std::make_tuple(TheUser, nullptr, nullptr));
else
Builder.CreateCall(TheModule.getFunction("abort"));
break;
}
case Instruction::IntToPtr:
case Instruction::BitCast:
{
// A bitcast, just propagate it
WorkList.push(CurrentOffset, TheUser);
break;
}
case Instruction::GetElementPtr:
{
// A GEP requires to update the offset
auto *GEP = cast<GetElementPtrInst>(TheUser);
unsigned AS = GEP->getPointerAddressSpace();
APInt APOffset(DL.getPointerSizeInBits(AS), 0, true);
bool Result = GEP->accumulateConstantOffset(DL, APOffset);
// TODO: do some kind of warning reporting here
// TODO: split the basic block and add an unreachable here
if (!Result) {
CallInst::Create(TheModule.getFunction("abort"), { }, GEP);
continue;
}
int64_t NewOffset = APOffset.getSExtValue();
WorkList.push(CurrentOffset + NewOffset, TheUser);
break;
}
case Instruction::Add:
{
unsigned OtherOperandIndex = 1 - TheUse.getOperandNo();
Value *OtherOperand = TheUser->getOperand(OtherOperandIndex);
if (!isa<ConstantInt>(OtherOperand)) {
auto *InvalidInst = cast<Instruction>(TheUser);
CallInst::Create(TheModule.getFunction("abort"), { }, InvalidInst);
continue;
}
int64_t Addend = cast<ConstantInt>(OtherOperand)->getSExtValue();
WorkList.push(CurrentOffset + Addend, TheUser);
break;
}
case Instruction::Call:
{
auto *Call = cast<CallInst>(TheUser);
Function *Callee = Call->getCalledFunction();
// Some casting with constant expressions?
if (Callee == nullptr) {
if (auto *Cast = dyn_cast<ConstantExpr>(Call->getCalledValue())) {
assert(Cast->getOpcode() == Instruction::BitCast);
Callee = cast<Function>(Cast->getOperand(0));
}
}
if (Callee != nullptr
&& Callee->getIntrinsicID() == Intrinsic::dbg_declare)
continue;
// We only support memcpys where the last parameter is constant
if (Callee == nullptr
|| (Callee->getIntrinsicID() == Intrinsic::memcpy
&& !isa<ConstantInt>(Call->getArgOperand(2)))) {
auto *InvalidInst = cast<Instruction>(TheUser);
CallInst::Create(TheModule.getFunction("abort"), { }, InvalidInst);
continue;
}
// We're memcpy'ing to the env
if (Callee->getIntrinsicID() == Intrinsic::memcpy) {
IRBuilder<> Builder(TheModule.getContext());
Builder.SetInsertPoint(Call);
unsigned EnvOpIndex = (Call->getArgOperand(0) == CurrentValue ?
0 : 1);
Value *BaseOp = Call->getArgOperand(1 - EnvOpIndex);
auto *ValueOp = cast<Constant>(Call->getArgOperand(2));
Value *BasePtr = Builder.CreatePtrToInt(BaseOp,
Builder.getInt64Ty());
uint64_t TotalSize = getZExtValue(ValueOp, DL);
uint64_t Offset = 0;
while (Offset < TotalSize) {
GlobalVariable *Var = nullptr;
Var = Variables->getByCPUStateOffset(CurrentOffset + Offset);
// Consider the case when there's simply nothing there (alignment
// space)
if (Var == nullptr) {
Offset++;
continue;
}
Type *PointeeTy = Var->getType()->getPointerElementType();
uint64_t Size = DL.getTypeSizeInBits(PointeeTy) / 8;
Value *Address = Builder.CreateAdd(Builder.getInt64(Offset),
BasePtr);
Value *Ptr = Builder.CreateIntToPtr(Address, Var->getType());
if (EnvOpIndex == 0)
Builder.CreateStore(Builder.CreateLoad(Ptr), Var);
else
Builder.CreateStore(Builder.CreateLoad(Var), Ptr);
Offset += Size;
}
if (Offset != TotalSize) {
auto *InvalidInstruction = cast<Instruction>(TheUser);
CallInst::Create(TheModule.getFunction("abort"),
{ },
InvalidInstruction);
continue;
}
// Set memcpy size to 0
auto *Zero = ConstantInt::get(Call->getArgOperand(2)->getType(), 0);
Call->setArgOperand(2, Zero);
continue;
}
assert((Callee->getName().startswith("helper")
|| !Callee->empty())
&& "external functions are not supported");
if (Callee->empty())
break;
// TODO: move all the specialization-handling code outside
// Is the callee already a specialization?
auto Comparison = [&Callee] (Specialization &S) {
return S.F == Callee;
};
auto CurrentSpecialization = std::find_if(Specializations.begin(),
Specializations.end(),
Comparison);
Function *Original = Callee;
std::vector<std::pair<unsigned, int64_t>> SpecializedArgs;
// If the callee was already a specialization, preserve its
// specialized arguments
if (CurrentSpecialization != Specializations.end()) {
// Check if we're good with this specialization
bool SpecializationMatches = false;
for (auto &P : CurrentSpecialization->SpecializedArgs) {
if (P.first == TheUse.getOperandNo()) {
assert(P.second == CurrentOffset);
SpecializationMatches = true;
break;
}
}
if (SpecializationMatches)
continue;
Original = CurrentSpecialization->Original;
SpecializedArgs = CurrentSpecialization->SpecializedArgs;
}
// Add the new argument to specialize
SpecializedArgs.push_back({ TheUse.getOperandNo(), CurrentOffset });
// Does the specialization we want already exists?
Specialization *Matching = nullptr;
for (Specialization &S : Specializations) {
if (S.Original == Original
&& S.SpecializedArgs.size() == SpecializedArgs.size()) {
Matching = &S;
for (std::pair<unsigned, int64_t> A : SpecializedArgs) {
bool Found = false;
for (std::pair<unsigned, int64_t> B : S.SpecializedArgs) {
if (A.first == B.first && A.second == B.second) {
Found = true;
break;
}
}
if (!Found) {
Matching = nullptr;
break;
}
}
if (Matching != nullptr)
break;
}
}
if (Matching == nullptr) {
// We need a new specialization
ValueToValueMapTy VTV;
SmallVector<ReturnInst *, 5> Returns;
// Clone existing function
std::stringstream NewName;
NewName << Callee->getName().str() << "_" << Specializations.size();
Callee->setLinkage(GlobalValue::InternalLinkage);
Function *NewFunc = Function::Create(Callee->getFunctionType(),
GlobalValue::InternalLinkage,
NewName.str(),
Callee->getParent());
unsigned I = 0;
auto CalleeArg = Callee->arg_begin();
auto NewArg = NewFunc->arg_begin();
for (CalleeArg = Callee->arg_begin();
CalleeArg != Callee->arg_end();
CalleeArg++) {
NewArg->setName(CalleeArg->getName());
WorkList.cloneSisters(&*CalleeArg, &*NewArg);
VTV[&*CalleeArg] = &*NewArg++;
}
CloneFunctionInto(NewFunc, Callee, VTV, true, Returns);
Specialization New;
New.F = NewFunc;
New.Original = Original;
New.SpecializedArgs = SpecializedArgs;
Specializations.push_back(New);
Matching = &Specializations.back();
// The function is new, we have to explore its argument usage
// Find the corresponding argument
auto ArgsI = NewFunc->arg_begin();
for (I = 0;
I < Call->getNumArgOperands() && ArgsI != NewFunc->arg_end();
I++, ArgsI++) {
Use& ArgUse = Call->getArgOperandUse(I);
if (ArgUse.getOperandNo() == TheUse.getOperandNo())
break;
}
assert(I < Call->getNumArgOperands()
&& ArgsI != NewFunc->arg_end());
Value *TargetArg = static_cast<Value *>(&*ArgsI);
if (TargetArg->use_begin() != TargetArg->use_end()) {
assert(!NewFunc->isVarArg());
// If not already considered, enqueue the argument to the worklist
WorkList.pushIfNew(CurrentOffset, TargetArg);
}
}
auto It = OffsetFunctions.find(Matching->F);
if (It != OffsetFunctions.end())
WorkList.push(It->second, static_cast<Value *>(Call));
auto *OriginalCalleeTy = Call->getCalledValue()->getType();
Call->setCalledFunction(ConstantExpr::getBitCast(Matching->F,
OriginalCalleeTy));
break;
}
case Instruction::Ret:
{
// This function returns a pointer to the state
Function *CurrentFunction = TheUser->getParent()->getParent();
OffsetFunctions[CurrentFunction] = CurrentOffset;
for (User *FunctionUse : CurrentFunction->users()) {
auto Call = cast<CallInst>(FunctionUse);
assert(Call->getCalledFunction() == CurrentFunction);
WorkList.pushIfNew(CurrentOffset, static_cast<Value *>(Call));
}
break;
}
default:
// Unhandled situation, propagate an error value until the next load
WorkList.push(ErrorOffset, TheUser);
}
}
for (auto Replacement : Replacements)
if (std::get<1>(Replacement) == nullptr)
cast<Instruction>(std::get<0>(Replacement))->eraseFromParent();
else
std::get<0>(Replacement)->replaceUsesOfWith(std::get<1>(Replacement),
std::get<2>(Replacement));
}
return true;
}
char CorrectCPUStateUsagePass::ID = 0;
static RegisterPass<CorrectCPUStateUsagePass> X("correct-cpustate-usage",
"Correct CPUState Usage Pass",
false,
false);
static std::pair<Type *, unsigned> getTypeAtOffset(const DataLayout *TheLayout,
StructType *TheStruct,
intptr_t Offset,
unsigned Depth=0) {
const StructLayout *Layout = TheLayout->getStructLayout(TheStruct);
unsigned FieldIndex = Layout->getElementContainingOffset(Offset);
uint64_t FieldOffset = Layout->getElementOffset(FieldIndex);
Type *VariableType = TheStruct->getTypeAtIndex(FieldIndex);
intptr_t FieldEnd = (FieldOffset
+ TheLayout->getTypeSizeInBits(VariableType) / 8);
DBG("type-at-offset", dbg
<< std::string(Depth * 2, ' ')
<< "Offset: " << Offset << " "
<< "Name: " << TheStruct->getName().str() << " "
<< "Index: " << FieldIndex << " "
<< "Field offset: " << FieldOffset << " "
<< "\n");
if (Offset >= FieldEnd)
return { nullptr, 0 };
if (VariableType->isIntegerTy())
return { VariableType, Offset - FieldOffset };
else if (VariableType->isArrayTy()) {
Type *ElementType = VariableType->getArrayElementType();
uint64_t ElementSize = TheLayout->getTypeSizeInBits(ElementType) / 8;
if (ElementType->isIntegerTy())
return { ElementType, (Offset - FieldOffset) % ElementSize };
return getTypeAtOffset(TheLayout,
cast<StructType>(ElementType),
(Offset - FieldOffset) % ElementSize,
Depth + 1);
} else if (VariableType->isStructTy())
return getTypeAtOffset(TheLayout,
cast<StructType>(VariableType),
Offset - FieldOffset,
Depth + 1);
else {
// TODO: do some kind of warning reporting here
return { nullptr, 0 };
}
}
VariableManager::VariableManager(Module& TheModule,
Module& HelpersModule,
Architecture& TargetArchitecture) :
TheModule(TheModule),
Builder(TheModule.getContext()),
CPUStateType(nullptr),
ModuleLayout(&HelpersModule.getDataLayout()),
EnvOffset(0),
Env(nullptr),
AliasScopeMDKindID(TheModule.getMDKindID("alias.scope")),
NoAliasMDKindID(TheModule.getMDKindID("noalias")),
TargetArchitecture(TargetArchitecture) {
auto *CPUStateAliasDomain = MDNode::getDistinct(TheModule.getContext(),
ArrayRef<Metadata *>());
auto *Temporary = MDNode::get(TheModule.getContext(), ArrayRef<Metadata *>());
auto *CPUStateScope = MDNode::getDistinct(TheModule.getContext(),
ArrayRef<Metadata *>({
Temporary,
CPUStateAliasDomain
}));
CPUStateScope->replaceOperandWith(0, CPUStateScope);
CPUStateScopeSet = MDNode::get(TheModule.getContext(),
ArrayRef<Metadata *>({ CPUStateScope }));
assert(ptc.initialized_env != nullptr);
using ElectionMap = std::map<StructType *, unsigned>;
using ElectionMapElement = std::pair<StructType * const, unsigned>;
ElectionMap EnvElection;
const std::string HelperPrefix = "helper_";
std::set<StructType *> Structs;
for (Function& HelperFunction : HelpersModule) {
FunctionType *HelperType = HelperFunction.getFunctionType();
Type *ReturnType = HelperType->getReturnType();
if (ReturnType->isPointerTy())
Structs.insert(dyn_cast<StructType>(ReturnType->getPointerElementType()));
for (Type *Param : HelperType->params())
if (Param->isPointerTy())
Structs.insert(dyn_cast<StructType>(Param->getPointerElementType()));
if (startsWith(HelperFunction.getName(), HelperPrefix)
&& HelperFunction.getFunctionType()->getNumParams() > 1) {
for (Type *Candidate : HelperType->params()) {
Structs.insert(dyn_cast<StructType>(Candidate));
if (Candidate->isPointerTy()) {
auto *PointeeType = Candidate->getPointerElementType();
auto *EnvType = dyn_cast<StructType>(PointeeType);
// Ensure it is a struct and not a union
if (EnvType != nullptr && EnvType->getNumElements() > 1) {
auto It = EnvElection.find(EnvType);
if (It != EnvElection.end())
EnvElection[EnvType]++;
else
EnvElection[EnvType] = 1;
}
}
}
}
}
Structs.erase(nullptr);
assert(EnvElection.size() > 0);
CPUStateType = std::max_element(EnvElection.begin(),
EnvElection.end(),
[] (ElectionMapElement& It1,
ElectionMapElement& It2) {
return It1.second < It2.second;
})->first;
// Look for structures containing CPUStateType as a member and promove them
// to CPUStateType. Basically this is a flexible way to keep track of the *CPU
// struct too (e.g. MIPSCPU).
std::set<StructType *> Visited;
bool Changed = true;
Visited.insert(CPUStateType);
while (Changed) {
Changed = false;
for (StructType *TheStruct : Structs) {
if (Visited.find(TheStruct) != Visited.end())
continue;
auto Begin = TheStruct->element_begin();
auto End = TheStruct->element_end();
auto Found = std::find(Begin, End, CPUStateType);
if (Found != End) {
unsigned Index = Found - Begin;
const StructLayout *Layout = nullptr;
Layout = ModuleLayout->getStructLayout(TheStruct);
EnvOffset += Layout->getElementOffset(Index);
CPUStateType = TheStruct;
Visited.insert(CPUStateType);
Changed = true;
break;
}
}
}
}
bool VariableManager::storeToCPUStateOffset(IRBuilder<> &Builder,
unsigned StoreSize,
unsigned Offset,
Value *ToStore) {
Value *Target;
unsigned Remaining;
std::tie(Target, Remaining) = getByCPUStateOffsetInternal(Offset);
assert(Target != nullptr);
if (Target == nullptr)
return false;
unsigned ShiftAmount = 0;
if (TargetArchitecture.isLittleEndian())
ShiftAmount = Remaining;
else {
// >> (Size1 - Size2) - Remaining;
Type *PointeeTy = Target->getType()->getPointerElementType();
unsigned GlobalSize = cast<IntegerType>(PointeeTy)->getBitWidth() / 8;
assert(GlobalSize != 0);
ShiftAmount = (GlobalSize - StoreSize) - Remaining;
}
ShiftAmount *= 8;
// Build blanking mask
uint64_t BitMask = (StoreSize == 8 ?
(uint64_t) -1
: ((uint64_t) 1 << StoreSize * 8) - 1);
assert(ShiftAmount != 64);
BitMask <<= ShiftAmount;
BitMask = ~BitMask;
auto *InputStoreTy = cast<IntegerType>(Builder.getIntNTy(StoreSize * 8));
auto *FieldTy = cast<IntegerType>(Target->getType()->getPointerElementType());
unsigned FieldSize = FieldTy->getBitWidth() / 8;
// Truncate value to store
auto *Truncated = Builder.CreateTrunc(ToStore, InputStoreTy);
// Are we trying to store more than it fits?
if (StoreSize > FieldSize) {
// It's OK as long as after what we're storing there's a hole
assert(getByCPUStateOffsetInternal(Offset + FieldSize).first == nullptr);
Truncated = Builder.CreateTrunc(Truncated, FieldTy);
}
// Re-extend
ToStore = Builder.CreateZExt(Truncated, FieldTy);
if (BitMask != 0) {
// Load the value
auto *LoadEnvField = Builder.CreateLoad(Target);
setAliasScope(LoadEnvField);
auto *Blanked = Builder.CreateAnd(LoadEnvField, BitMask);
// Shift value to store
ToStore = Builder.CreateShl(ToStore, ShiftAmount);
// Combine them
ToStore = Builder.CreateOr(ToStore, Blanked);
}
// Type *TargetPointer = Target->getType()->getPointerElementType();
// Value *ToStore = Builder.CreateZExt(InArguments[0], TargetPointer);
auto *Store = Builder.CreateStore(ToStore, Target);
setAliasScope(Store);
return true;
}
Value *VariableManager::loadFromCPUStateOffset(IRBuilder<> &Builder,
unsigned LoadSize,
unsigned Offset) {
Value *Target;
unsigned Remaining;
std::tie(Target, Remaining) = getByCPUStateOffsetInternal(Offset);
if (Target == nullptr)
return nullptr;
// Load the whole field
auto *LoadEnvField = Builder.CreateLoad(Target);
setAliasScope(LoadEnvField);
// Extract the desired part
// Shift right of the desired amount
unsigned ShiftAmount = 0;
if (TargetArchitecture.isLittleEndian())
ShiftAmount = Remaining;
else {
// >> (Size1 - Size2) - Remaining;
auto *LoadedTy = cast<IntegerType>(LoadEnvField->getType());
unsigned GlobalSize = LoadedTy->getBitWidth() / 8;
assert(GlobalSize != 0);
ShiftAmount = (GlobalSize - LoadSize) - Remaining;
}
ShiftAmount *= 8;
Value *Result = LoadEnvField;
if (ShiftAmount != 0)
Result = Builder.CreateLShr(Result, ShiftAmount);
Type *LoadTy = Builder.getIntNTy(LoadSize * 8);
// Are we trying to load more than its available in the field?
if (auto FieldTy = dyn_cast<IntegerType>(Result->getType())) {
unsigned FieldSize = FieldTy->getBitWidth() / 8;
if (FieldSize < LoadSize) {
// It's OK as long as after what we can't load there's a hole
assert(getByCPUStateOffsetInternal(Offset + FieldSize).first == nullptr);
Result = Builder.CreateZExt(Result, LoadTy);
}
}
// Truncate of the desired amount
return Builder.CreateTrunc(Result, LoadTy);
}
// TODO: `newFunction` reflects the tcg terminology but in this context is
// highly misleading
void VariableManager::newFunction(Instruction *Delimiter,
PTCInstructionList *Instructions) {
LocalTemporaries.clear();
newBasicBlock(Delimiter, Instructions);
}
/// Informs the VariableManager that a new basic block has begun, so it can
/// discard basic block-level variables.
///
/// \param Delimiter the new point where to insert allocations for local
/// variables.
/// \param Instructions the new PTCInstructionList to use from now on.
void VariableManager::newBasicBlock(Instruction *Delimiter,
PTCInstructionList *Instructions) {
Temporaries.clear();
if (Instructions != nullptr)
this->Instructions = Instructions;
if (Delimiter != nullptr)
Builder.SetInsertPoint(Delimiter);
}
void VariableManager::newBasicBlock(BasicBlock *Delimiter,
PTCInstructionList *Instructions) {
Temporaries.clear();
if (Instructions != nullptr)
this->Instructions = Instructions;
if (Delimiter != nullptr)
Builder.SetInsertPoint(Delimiter);
}
bool VariableManager::isEnv(Value *TheValue) {
auto *Load = dyn_cast<LoadInst>(TheValue);
if (Load != nullptr)
return Load->getPointerOperand() == Env;
return TheValue == Env;
}
static ConstantInt *fromBytes(IntegerType *Type, void *Data) {
switch (Type->getBitWidth()) {
case 8:
return ConstantInt::get(Type, *(static_cast<uint8_t *>(Data)));
case 16:
return ConstantInt::get(Type, *(static_cast<uint16_t *>(Data)));
case 32:
return ConstantInt::get(Type, *(static_cast<uint32_t *>(Data)));
case 64:
return ConstantInt::get(Type, *(static_cast<uint64_t *>(Data)));
}
llvm_unreachable("Unexpected type");
}
// TODO: document that it can return nullptr
GlobalVariable* VariableManager::getByCPUStateOffset(intptr_t Offset,
std::string Name) {
GlobalVariable *Result = nullptr;
unsigned Remaining;
std::tie(Result, Remaining) = getByCPUStateOffsetInternal(Offset, Name);
assert(Remaining == 0);
return Result;
}
std::pair<GlobalVariable*, unsigned>
VariableManager::getByCPUStateOffsetInternal(intptr_t Offset,
std::string Name) {
if (Offset == ErrorOffset)
return { nullptr, 0 };
GlobalsMap::iterator it = CPUStateGlobals.find(Offset);
if (it == CPUStateGlobals.end() ||
(Name.size() != 0 && !it->second->getName().equals_lower(Name))) {
Type *VariableType;
unsigned Remaining;
std::tie(VariableType, Remaining) = getTypeAtOffset(ModuleLayout,
CPUStateType,
Offset);
// Check we're not trying to go inside an existing variable
if (Remaining != 0) {
GlobalsMap::iterator it = CPUStateGlobals.find(Offset - Remaining);
if (it != CPUStateGlobals.end())
return { it->second, Remaining };
}
// Unsupported type, let the caller handle the situation
if (VariableType == nullptr)
return { nullptr, 0 };
if (Name.size() == 0) {
std::stringstream NameStream;
NameStream << "state_0x" << std::hex << Offset;
Name = NameStream.str();
}
// TODO: offset could be negative, we could segfault here
auto *InitialValue = fromBytes(cast<IntegerType>(VariableType),
ptc.initialized_env - EnvOffset + Offset);
auto *NewVariable = new GlobalVariable(TheModule,
VariableType,
false,
GlobalValue::ExternalLinkage,
InitialValue,
Name);
assert(NewVariable != nullptr);
if (it != CPUStateGlobals.end()) {
it->second->replaceAllUsesWith(NewVariable);
it->second->eraseFromParent();
}
CPUStateGlobals[Offset] = NewVariable;
return { NewVariable, Remaining };
} else {
return { it->second, 0 };
}
}
Value *VariableManager::getOrCreate(unsigned TemporaryId, bool Reading) {
assert(Instructions != nullptr);
PTCTemp *Temporary = ptc_temp_get(Instructions, TemporaryId);
Type *VariableType = Temporary->type == PTC_TYPE_I32 ?
Builder.getInt32Ty() : Builder.getInt64Ty();
if (ptc_temp_is_global(Instructions, TemporaryId)) {
// Basically we use fixed_reg to detect "env"
if (Temporary->fixed_reg == 0) {
Value *Result = getByCPUStateOffset(EnvOffset + Temporary->mem_offset,
StringRef(Temporary->name));
assert(Result != nullptr);
return Result;
} else {
GlobalsMap::iterator it = OtherGlobals.find(TemporaryId);
if (it != OtherGlobals.end()) {
return it->second;
} else {
// TODO: what do we have here, apart from env?
auto InitialValue = ConstantInt::get(VariableType, 0);
GlobalVariable *Result = new GlobalVariable(TheModule,
VariableType,
false,
GlobalValue::CommonLinkage,
InitialValue,
StringRef(Temporary->name));
if (Result->getName() == "env")
Env = Result;
OtherGlobals[TemporaryId] = Result;
return Result;
}
}
} else if (Temporary->temp_local) {
auto it = LocalTemporaries.find(TemporaryId);
if (it != LocalTemporaries.end()) {
return it->second;
} else {
AllocaInst *NewTemporary = Builder.CreateAlloca(VariableType);
LocalTemporaries[TemporaryId] = NewTemporary;
return NewTemporary;
}
} else {
auto it = Temporaries.find(TemporaryId);
if (it != Temporaries.end()) {
return it->second;
} else {
// Can't read a temporary if it has never been written, we're probably
// translating rubbish
if (Reading)
return nullptr;
AllocaInst *NewTemporary = Builder.CreateAlloca(VariableType);
Temporaries[TemporaryId] = NewTemporary;
return NewTemporary;
}
}
}
template LoadInst *VariableManager::setAliasScope(LoadInst *);
template StoreInst *VariableManager::setAliasScope(StoreInst *);
template<typename T>
T *VariableManager::setAliasScope(T *Instruction) {
auto *Pointer = Instruction->getPointerOperand();
if (isa<AllocaInst>(Pointer))
return Instruction;
Instruction->setMetadata(AliasScopeMDKindID, CPUStateScopeSet);
return Instruction;
}
template LoadInst *VariableManager::setNoAlias(LoadInst *);
template StoreInst *VariableManager::setNoAlias(StoreInst *);
template<typename T>
T *VariableManager::setNoAlias(T *Instruction) {
Instruction->setMetadata(NoAliasMDKindID, CPUStateScopeSet);
return Instruction;
}
Value *VariableManager::computeEnvAddress(Type *TargetType,
Instruction *InsertBefore,
unsigned Offset) {
auto *LoadEnv = new LoadInst(Env, "", InsertBefore);
Type *EnvType = Env->getType()->getPointerElementType();
Value *Integer = LoadEnv;
if (Offset != 0)
Integer = BinaryOperator::Create(Instruction::Add,
LoadEnv,
ConstantInt::get(EnvType, Offset),
"",
InsertBefore);
return new IntToPtrInst(Integer, TargetType, "", InsertBefore);
}
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