mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Alessandro Di Federico
0c671ea7ae
RemoveExceptionalCalls is a simple pass whose goal is to drop all the calls to functions marked as `Exceptional` and replace them with an `UnrechableInst`. This is mainly useful in the decompilation pipeline.
62 lines
1.7 KiB
C++
62 lines
1.7 KiB
C++
/// \file RemoveExceptionalCalls.cpp
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/// \brief
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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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#include "llvm/IR/Function.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "revng/FunctionIsolation/RemoveExceptionalCalls.h"
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#include "revng/Support/FunctionTags.h"
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#include "revng/Support/IRHelpers.h"
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using namespace llvm;
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char RemoveExceptionalCalls::ID = 0;
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using Register = RegisterPass<RemoveExceptionalCalls>;
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static Register
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X("remove-exceptional-functions", "Remove Exceptional Functions");
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bool RemoveExceptionalCalls::runOnModule(llvm::Module &M) {
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LLVMContext &C = M.getContext();
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// Collect all calls to exceptional functions in lifted functions
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std::set<CallBase *> ToErase;
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for (Function &F : FunctionTags::Exceptional.functions(&M))
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for (CallBase *Call : callers(&F))
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if (FunctionTags::Lifted.isTagOf(Call->getParent()->getParent()))
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ToErase.insert(Call);
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std::set<Function *> ToCleanup;
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for (CallBase *Call : ToErase) {
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BasicBlock *BB = Call->getParent();
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// Register function for cleanup
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ToCleanup.insert(BB->getParent());
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// Split containing basic block
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BB->splitBasicBlock(Call);
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// Drop terminator of the old basic block
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BB->getTerminator()->eraseFromParent();
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// Terminate with an unreachable
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new UnreachableInst(C, BB);
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// Drop function call
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auto *Undef = UndefValue::get(Call->getType());
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Call->replaceAllUsesWith(Undef);
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Call->eraseFromParent();
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}
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// Garbage collect dead blocks
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for (Function *F : ToCleanup)
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EliminateUnreachableBlocks(*F, nullptr, false);
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return true;
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}
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