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revng-revng/lib/BasicAnalyses/GeneratedCodeBasicInfo.cpp
T
Alessandro Di Federico dc48188f37 Introduce MetaAddress
`MetaAddress` replaces all the `uint64_t` used to represent a virtual
address. Its main features are:

* It has a non-zero representation of invalid addresses.
* It supports tags to represent code that has different interpretations but
  resides at the same address in memory (namely ARM vs Thumb).
* Arithmetic operations cannot overflow.
* It supports epochs, a way we intend to employ to handle self-modifying code
  (i.e., different code at the same address at different times).
* It supports "address spaces", which enable handling architectures with
  multiple address spaces.
* It fits in two 64-bit registers.
2020-05-14 11:58:18 +02:00

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/// \file GeneratedCodeBasicInfo.cpp
/// \brief Implements the GeneratedCodeBasicInfo pass which provides basic
/// information about the translated code (e.g., which CSV is the PC).
//
// This file is distributed under the MIT License. See LICENSE.md for details.
//
// Standard includes
#include <queue>
#include <set>
// LLVM includes
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
// Local libraries includes
#include "revng/BasicAnalyses/GeneratedCodeBasicInfo.h"
#include "revng/Support/Debug.h"
using namespace llvm;
char GeneratedCodeBasicInfo::ID = 0;
using RegisterGCBI = RegisterPass<GeneratedCodeBasicInfo>;
static RegisterGCBI X("gcbi", "Generated Code Basic Info", true, true);
bool GeneratedCodeBasicInfo::runOnModule(llvm::Module &M) {
Function &F = *M.getFunction("root");
NewPC = M.getFunction("newpc");
if (NewPC != nullptr) {
MetaAddressStruct = cast<StructType>(NewPC->arg_begin()->getType());
}
revng_log(PassesLog, "Starting GeneratedCodeBasicInfo");
RootFunction = &F;
const char *MDName = "revng.input.architecture";
NamedMDNode *InputArchMD = M.getOrInsertNamedMetadata(MDName);
auto *Tuple = dyn_cast<MDTuple>(InputArchMD->getOperand(0));
QuickMetadata QMD(M.getContext());
{
unsigned Index = 0;
StringRef ArchTypeName = QMD.extract<StringRef>(Tuple, Index++);
ArchType = Triple::getArchTypeForLLVMName(ArchTypeName);
InstructionAlignment = QMD.extract<uint32_t>(Tuple, Index++);
DelaySlotSize = QMD.extract<uint32_t>(Tuple, Index++);
PC = M.getGlobalVariable(QMD.extract<StringRef>(Tuple, Index++), true);
SP = M.getGlobalVariable(QMD.extract<StringRef>(Tuple, Index++), true);
auto Operands = QMD.extract<MDTuple *>(Tuple, Index++)->operands();
for (const MDOperand &Operand : Operands) {
StringRef Name = QMD.extract<StringRef>(Operand.get());
revng_assert(Name != "pc", "PC should not be considered an ABI register");
GlobalVariable *CSV = M.getGlobalVariable(Name, true);
ABIRegisters.push_back(CSV);
}
}
Type *PCType = PC->getType()->getPointerElementType();
PCRegSize = M.getDataLayout().getTypeAllocSize(PCType);
for (BasicBlock &BB : F) {
if (!BB.empty()) {
switch (getType(&BB)) {
case BlockType::DispatcherBlock:
revng_assert(Dispatcher == nullptr);
Dispatcher = &BB;
break;
case BlockType::DispatcherFailureBlock:
revng_assert(DispatcherFail == nullptr);
DispatcherFail = &BB;
break;
case BlockType::AnyPCBlock:
revng_assert(AnyPC == nullptr);
AnyPC = &BB;
break;
case BlockType::UnexpectedPCBlock:
revng_assert(UnexpectedPC == nullptr);
UnexpectedPC = &BB;
break;
case BlockType::JumpTargetBlock: {
auto *Call = cast<CallInst>(&*BB.begin());
revng_assert(Call->getCalledFunction()->getName() == "newpc");
JumpTargets[MetaAddress::fromConstant(Call->getArgOperand(0))] = &BB;
break;
}
case BlockType::EntryPoint:
case BlockType::ExternalJumpsHandlerBlock:
case BlockType::UntypedBlock:
// Nothing to do here
break;
}
}
}
revng_assert(Dispatcher != nullptr && AnyPC != nullptr
&& UnexpectedPC != nullptr);
if (auto *NamedMD = M.getNamedMetadata("revng.csv")) {
auto *Tuple = cast<MDTuple>(NamedMD->getOperand(0));
for (const MDOperand &Operand : Tuple->operands()) {
auto *CSV = cast<GlobalVariable>(QMD.extract<Constant *>(Operand.get()));
CSVs.push_back(CSV);
}
}
revng_log(PassesLog, "Ending GeneratedCodeBasicInfo");
return false;
}