mirror of
https://github.com/lifting-bits/remill
synced 2026-06-21 13:56:07 +00:00
Peter Goodman
81 lines
2.4 KiB
C++
81 lines
2.4 KiB
C++
/* Copyright 2015 Peter Goodman (peter@trailofbits.com), all rights reserved. */
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#include <glog/logging.h>
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#include <llvm/IR/BasicBlock.h>
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#include <llvm/IR/Function.h>
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#include <llvm/IR/IRBuilder.h>
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#include <llvm/IR/Module.h>
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#include "mcsema/BC/Util.h"
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namespace mcsema {
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llvm::Function *&BlockMap::operator[](uintptr_t pc) {
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return this->std::unordered_map<uintptr_t, llvm::Function *>::operator[](pc);
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}
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llvm::Function *BlockMap::operator[](uintptr_t pc) const {
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const auto block_it = this->find(pc);
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if (this->end() == block_it) {
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LOG(WARNING) << "No block associated with PC " << pc;
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return nullptr;
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} else {
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return block_it->second;
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}
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}
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void InitFunctionAttributes(llvm::Function *F) {
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F->removeFnAttr(llvm::Attribute::NoReturn);
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F->addFnAttr(llvm::Attribute::NoUnwind);
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F->removeFnAttr(llvm::Attribute::UWTable);
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F->setCallingConv(llvm::CallingConv::Fast);
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F->setAlignment(0);
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}
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// Create a tail-call from one lifted function to another.
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void AddTerminatingTailCall(llvm::Function *From, llvm::Function *To) {
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if (From->isDeclaration()) {
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llvm::BasicBlock::Create(From->getContext(), "entry", From);
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}
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AddTerminatingTailCall(&(From->back()), To);
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}
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void AddTerminatingTailCall(llvm::BasicBlock *B, llvm::Function *To) {
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LOG_IF(ERROR, B->getTerminator() || B->getTerminatingMustTailCall())
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<< "Block already has a terminator; not adding fall-through call to: "
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<< (To ? To->getName().str() : "<unreachable>");
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llvm::IRBuilder<> ir(B);
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if (!To) {
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LOG(WARNING) << "Target block does not exist!";
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ir.CreateUnreachable();
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} else {
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llvm::Function *F = B->getParent();
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llvm::CallInst *C = ir.CreateCall(To, {FindStatePointer(F)});
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C->setTailCallKind(llvm::CallInst::TCK_MustTail);
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C->setCallingConv(llvm::CallingConv::Fast);
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ir.CreateRetVoid();
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}
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}
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// Find a local variable defined in the entry block of the function. We use
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// this to find register variables.
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llvm::Value *FindVarInFunction(llvm::Function *F, std::string name) {
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for (auto &I : F->getEntryBlock()) {
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if (I.getName() == name) {
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return &I;
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}
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}
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LOG(FATAL) << "Could not find variable " << name << " in function "
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<< F->getName().str();
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return nullptr;
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}
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// Find the machine state pointer.
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llvm::Value *FindStatePointer(llvm::Function *F) {
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return &*F->getArgumentList().begin();
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}
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} // namespace mcsema
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