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revng-revng/include/revng/BasicAnalyses/FunctionCallIdentification.h
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2018-11-14 14:41:25 +01:00

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#ifndef FUNCTIONCALLIDENTIFICATION_H
#define FUNCTIONCALLIDENTIFICATION_H
//
// This file is distributed under the MIT License. See LICENSE.md for details.
//
// LLVM includes
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
// Local libraries includes
#include "revng/BasicAnalyses/GeneratedCodeBasicInfo.h"
#include "revng/Support/IRHelpers.h"
/// \brief Identify function call instructions
///
/// This pass parses the generated IR looking for terminator instructions which
/// look like function calls, i.e., they store the next program counter (the
/// return address) to a CSV (the link register) or in memory (the stack).
///
/// The pass also injects a call to the "funcion_call" function before
/// terminator instructions identified. The first argument represents the callee
/// basic block, the second the return basic block and the third the return
/// address.
class FunctionCallIdentification : public llvm::FunctionPass {
public:
static char ID;
public:
FunctionCallIdentification() : llvm::FunctionPass(ID) {}
void getAnalysisUsage(llvm::AnalysisUsage &AU) const override {
AU.setPreservesAll();
AU.addRequired<GeneratedCodeBasicInfo>();
}
bool runOnFunction(llvm::Function &F) override;
llvm::CallInst *getCall(llvm::Instruction *I) const {
return getCall(llvm::cast<llvm::TerminatorInst>(I));
}
llvm::CallInst *getCall(llvm::BasicBlock *BB) const {
return getCall(BB->getTerminator());
}
/// \brief Return true if \p T is a function call in the input assembly
llvm::CallInst *getCall(llvm::TerminatorInst *T) const {
revng_assert(T != nullptr);
llvm::Instruction *Previous = getPrevious(T);
while (Previous != nullptr && isMarker(Previous)) {
auto *Call = llvm::cast<llvm::CallInst>(Previous);
if (Call->getCalledFunction() == FunctionCall)
return Call;
Previous = getPrevious(Previous);
}
return nullptr;
}
/// \brief Return true if \p T is a function call in the input assembly
bool isCall(llvm::TerminatorInst *T) const { return getCall(T) != nullptr; }
bool isCall(llvm::Instruction *I) const { return getCall(I) != nullptr; }
bool isCall(llvm::BasicBlock *BB) const {
return isCall(BB->getTerminator());
}
llvm::BasicBlock *getFallthrough(llvm::BasicBlock *BB) const {
return getFallthrough(BB->getTerminator());
}
llvm::BasicBlock *getFallthrough(llvm::TerminatorInst *T) const {
revng_assert(T != nullptr);
llvm::Instruction *Previous = getPrevious(T);
while (Previous != nullptr && isMarker(Previous)) {
auto *Call = llvm::cast<llvm::CallInst>(Previous);
if (Call->getCalledFunction() == FunctionCall) {
auto *Fallthrough = llvm::cast<llvm::BlockAddress>(Call->getOperand(1));
return Fallthrough->getBasicBlock();
}
Previous = getPrevious(Previous);
}
revng_abort();
}
bool isFallthrough(uint64_t Address) const {
return FallthroughAddresses.count(Address) != 0;
}
bool isFallthrough(llvm::BasicBlock *BB) const {
return isFallthrough(getBasicBlockPC(BB));
}
bool isFallthrough(llvm::TerminatorInst *I) const {
return isFallthrough(I->getParent());
}
private:
llvm::Function *FunctionCall;
std::set<uint64_t> FallthroughAddresses;
};
#endif // FUNCTIONCALLIDENTIFICATION_H