mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Pietro Fezzardi
0eb179baf8
This commit makes possible to execute the GeneratedCodeBasicInfo (GCBI) Pass even on LLVM IR where the AnyPC and UnexpectedPC BasicBlocks are not present. This makes the GCBI pass more flexible, enabling more other passes to depend on it and to use it to retrieve informations on the generated code without architecture-dependent hacks. As an example, one can now use GCBI to retrieve the CSV representing the Stack Pointer Register or the Program Counter Register without relying on the register names (which are architecture-specific), even if some optimization pass along the decompilation pipeline has removed AnyPC or UnexpectedPC. Notice that the contracts of GCBI's methods has not been changed. Calling anyPC() or unexpectedPC() still asserts that those are not nullptr. The contract has just been moved from the execution stage of the pass (basically runOnModule), to the APIs used to query the results.
119 lines
3.7 KiB
C++
119 lines
3.7 KiB
C++
/// \file GeneratedCodeBasicInfo.cpp
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/// \brief Implements the GeneratedCodeBasicInfo pass which provides basic
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/// information about the translated code (e.g., which CSV is the PC).
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//
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// This file is distributed under the MIT License. See LICENSE.md for details.
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//
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// Standard includes
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#include <queue>
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#include <set>
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// LLVM includes
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Instructions.h"
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// Local libraries includes
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#include "revng/BasicAnalyses/GeneratedCodeBasicInfo.h"
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#include "revng/Support/Debug.h"
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using namespace llvm;
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char GeneratedCodeBasicInfo::ID = 0;
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using RegisterGCBI = RegisterPass<GeneratedCodeBasicInfo>;
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static RegisterGCBI X("gcbi", "Generated Code Basic Info", true, true);
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bool GeneratedCodeBasicInfo::runOnModule(llvm::Module &M) {
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Function &F = *M.getFunction("root");
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NewPC = M.getFunction("newpc");
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if (NewPC != nullptr) {
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MetaAddressStruct = cast<StructType>(NewPC->arg_begin()->getType());
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}
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revng_log(PassesLog, "Starting GeneratedCodeBasicInfo");
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RootFunction = &F;
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const char *MDName = "revng.input.architecture";
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NamedMDNode *InputArchMD = M.getOrInsertNamedMetadata(MDName);
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auto *Tuple = dyn_cast<MDTuple>(InputArchMD->getOperand(0));
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QuickMetadata QMD(M.getContext());
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{
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unsigned Index = 0;
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StringRef ArchTypeName = QMD.extract<StringRef>(Tuple, Index++);
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ArchType = Triple::getArchTypeForLLVMName(ArchTypeName);
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InstructionAlignment = QMD.extract<uint32_t>(Tuple, Index++);
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DelaySlotSize = QMD.extract<uint32_t>(Tuple, Index++);
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PC = M.getGlobalVariable(QMD.extract<StringRef>(Tuple, Index++), true);
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SP = M.getGlobalVariable(QMD.extract<StringRef>(Tuple, Index++), true);
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auto Operands = QMD.extract<MDTuple *>(Tuple, Index++)->operands();
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for (const MDOperand &Operand : Operands) {
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StringRef Name = QMD.extract<StringRef>(Operand.get());
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revng_assert(Name != "pc", "PC should not be considered an ABI register");
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GlobalVariable *CSV = M.getGlobalVariable(Name, true);
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ABIRegisters.push_back(CSV);
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ABIRegistersSet.insert(CSV);
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}
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}
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Type *PCType = PC->getType()->getPointerElementType();
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PCRegSize = M.getDataLayout().getTypeAllocSize(PCType);
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for (BasicBlock &BB : F) {
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if (!BB.empty()) {
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switch (getType(&BB)) {
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case BlockType::RootDispatcherBlock:
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revng_assert(Dispatcher == nullptr);
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Dispatcher = &BB;
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break;
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case BlockType::DispatcherFailureBlock:
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revng_assert(DispatcherFail == nullptr);
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DispatcherFail = &BB;
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break;
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case BlockType::AnyPCBlock:
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revng_assert(AnyPC == nullptr);
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AnyPC = &BB;
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break;
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case BlockType::UnexpectedPCBlock:
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revng_assert(UnexpectedPC == nullptr);
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UnexpectedPC = &BB;
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break;
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case BlockType::JumpTargetBlock: {
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auto *Call = cast<CallInst>(&*BB.begin());
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revng_assert(Call->getCalledFunction()->getName() == "newpc");
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JumpTargets[MetaAddress::fromConstant(Call->getArgOperand(0))] = &BB;
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break;
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}
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case BlockType::RootDispatcherHelperBlock:
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case BlockType::IndirectBranchDispatcherHelperBlock:
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case BlockType::EntryPoint:
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case BlockType::ExternalJumpsHandlerBlock:
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case BlockType::TranslatedBlock:
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// Nothing to do here
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break;
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}
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}
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}
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revng_assert(Dispatcher != nullptr);
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if (auto *NamedMD = M.getNamedMetadata("revng.csv")) {
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auto *Tuple = cast<MDTuple>(NamedMD->getOperand(0));
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for (const MDOperand &Operand : Tuple->operands()) {
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auto *CSV = cast<GlobalVariable>(QMD.extract<Constant *>(Operand.get()));
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CSVs.push_back(CSV);
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}
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}
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revng_log(PassesLog, "Ending GeneratedCodeBasicInfo");
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return false;
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}
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