Files
revng-revng/lib/EarlyFunctionAnalysis/PromoteGlobalToLocalVars.cpp
Alessandro Di Federico f8bd4c3bac Move around some files in preparation for libtcg
* Make the following private headers public:
  * Lift/CPUStateAccessAnalysisPass.h
  * Lift/CSVOffsets.h
  * Lift/PTCDump.h
  * Lift/VariableManager.h
* Move from revngSupport to revngLift:
  * IRAnnotators.{h,cpp}
  * SelfReferencingDbgAnnotationWriter.{h,cpp}
* Move from revngSupport to revngModel:
  * FunctionTags.{h,cpp}
  * ProgramCounterHandler.{h,cpp}
* Move from revngSupport to revngRecompile:
  * OriginalAssemblyAnnotationWriter.{h,cpp}
2025-10-24 15:34:11 +02:00

56 lines
1.8 KiB
C++

/// \file PromoteGlobalToLocalVars.cpp
/// Promote CSVs in form of global variables to local variables.
//
// This file is distributed under the MIT License. See LICENSE.md for details.
//
#include "llvm/ADT/STLExtras.h"
#include "revng/EarlyFunctionAnalysis/PromoteGlobalToLocalVars.h"
#include "revng/Model/FunctionTags.h"
#include "revng/Support/IRHelpers.h"
#include "revng/Support/OpaqueRegisterUser.h"
using namespace llvm;
llvm::PreservedAnalyses
PromoteGlobalToLocalPass::run(llvm::Function &F,
llvm::FunctionAnalysisManager &FAM) {
// Collect the CSVs used by the current function.
std::map<GlobalVariable *, Value *> CSVMap;
for (auto &BB : F) {
for (auto &I : BB) {
Value *Pointer = nullptr;
if (auto *Load = dyn_cast<LoadInst>(&I))
Pointer = skipCasts(Load->getPointerOperand());
else if (auto *Store = dyn_cast<StoreInst>(&I))
Pointer = skipCasts(Store->getPointerOperand());
else
continue;
if (auto *CSV = dyn_cast_or_null<GlobalVariable>(Pointer))
CSVMap.try_emplace(CSV);
}
}
// TODO: the checks should be enabled conditionally based on the user.
revng::NonDebugInfoCheckingIRBuilder Builder(&F.getEntryBlock().front());
// Create an equivalent local variable, replace all the uses of the CSV.
for (GlobalVariable *CSV : toSortedByName(llvm::make_first_range(CSVMap))) {
auto *CSVTy = CSV->getValueType();
auto *Alloca = Builder.CreateAlloca(CSVTy, nullptr, CSV->getName());
replaceAllUsesInFunctionWith(&F, CSV, Alloca);
CSVMap[CSV] = Alloca;
}
// Load all the CSVs and store their value onto the local variables.
for (const auto &[CSV, Alloca] : CSVMap)
Builder.CreateStore(createLoad(Builder, CSV), Alloca);
return PreservedAnalyses::none();
}