mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Andrea Gussoni
371dc7ea97
We now craft a new decompilation pipeline. We remove the exceptions introduced as fallbacks to preserve the semantics, and we perform passes of `dce` and `simplifycfg` to remove all the superfluos basic block remaining after this change. To do this, we need an additional pass that removes also the calls to the `llvm.assume` intrinsic, and another pass of `dce` to remove all the dead uses. In addition, we also remove dead stores to the `cpu_loop_exiting` global variable in order to improve the decompiled code. As a byproduct of this, we remove also the dependency from the `-remove-pc-stores` pass, since its jobs is included by the changes mentioned above.
54 lines
1.4 KiB
C++
54 lines
1.4 KiB
C++
//
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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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// LLVM includes
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#include <llvm/ADT/SmallVector.h>
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#include <llvm/IR/Function.h>
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#include <llvm/IR/Module.h>
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// revng includes
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#include <revng/Support/IRHelpers.h>
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// Local libraries includes
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#include "revng-c/RemoveCpuLoopStore/RemoveCpuLoopStorePass.h"
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using namespace llvm;
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char RemoveCpuLoopStorePass::ID = 0;
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using Reg = RegisterPass<RemoveCpuLoopStorePass>;
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static Reg X("remove-cpu-loop-store", "Removes store to cpu_loop", true, true);
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bool RemoveCpuLoopStorePass::runOnFunction(Function &F) {
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if (not F.hasMetadata("revng.func.entry"))
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return false;
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// Retrieve the global variable `cpu_loop_exiting`
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Module *M = F.getParent();
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GlobalVariable *CpuLoop = M->getGlobalVariable("cpu_loop_exiting");
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// Remove in bulk all the users of the global variable. We directly cast
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// the user to a `llvm::StoreInst` by design (if we have another kind of user
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// our assumptions does not hold.
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SmallVector<Instruction *, 8> ToErase;
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for (User *U : CpuLoop->users()) {
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Instruction *I = cast<Instruction>(U);
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// Check only translated functions.
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if (I->getParent()->getParent() != &F)
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continue;
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StoreInst *Store = cast<StoreInst>(U);
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ToErase.push_back(Store);
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}
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// Remove in bulk all the store found before.
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bool Changed = not ToErase.empty();
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for (Instruction *I : ToErase) {
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I->eraseFromParent();
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}
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return Changed;
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}
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