llvm-project/llvm/lib/Transforms/Scalar/SymbolStripping.cpp

72 lines
2.2 KiB
C++

//===- SymbolStripping.cpp - Strip symbols for functions and modules ------===//
//
// This file implements stripping symbols out of symbol tables.
//
// Specifically, this allows you to strip all of the symbols out of:
// * A function
// * All functions in a module
// * All symbols in a module (all function symbols + all module scope symbols)
//
// Notice that:
// * This pass makes code much less readable, so it should only be used in
// situations where the 'strip' utility would be used (such as reducing
// code size, and making it harder to reverse engineer code).
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Scalar.h"
#include "llvm/Module.h"
#include "llvm/Function.h"
#include "llvm/SymbolTable.h"
#include "llvm/Pass.h"
static bool StripSymbolTable(SymbolTable *SymTab) {
if (SymTab == 0) return false; // No symbol table? No problem.
bool RemovedSymbol = false;
for (SymbolTable::iterator I = SymTab->begin(); I != SymTab->end(); ++I) {
std::map<const std::string, Value *> &Plane = I->second;
SymbolTable::type_iterator B;
while ((B = Plane.begin()) != Plane.end()) { // Found nonempty type plane!
Value *V = B->second;
if (isa<Constant>(V) || isa<Type>(V))
SymTab->type_remove(B);
else
V->setName("", SymTab); // Set name to "", removing from symbol table!
RemovedSymbol = true;
assert(Plane.begin() != B && "Symbol not removed from table!");
}
}
return RemovedSymbol;
}
namespace {
struct SymbolStripping : public FunctionPass {
const char *getPassName() const { return "Strip Symbols from Functions"; }
virtual bool runOnFunction(Function &F) {
return StripSymbolTable(F.getSymbolTable());
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
struct FullSymbolStripping : public SymbolStripping {
const char *getPassName() const { return "Strip Symbols from Module"; }
virtual bool doInitialization(Module &M) {
return StripSymbolTable(M.getSymbolTable());
}
};
}
Pass *createSymbolStrippingPass() {
return new SymbolStripping();
}
Pass *createFullSymbolStrippingPass() {
return new FullSymbolStripping();
}