forked from OSchip/llvm-project
86 lines
2.8 KiB
C++
86 lines
2.8 KiB
C++
//===- SymbolStripping.cpp - Strip symbols for functions and modules ------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements stripping symbols out of symbol tables.
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//
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// Specifically, this allows you to strip all of the symbols out of:
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// * All functions in a module
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// * All non-essential symbols in a module (all function symbols + all module
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// scope symbols)
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//
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// Notice that:
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// * This pass makes code much less readable, so it should only be used in
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// situations where the 'strip' utility would be used (such as reducing
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// code size, and making it harder to reverse engineer code).
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Module.h"
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#include "llvm/SymbolTable.h"
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#include "llvm/Pass.h"
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using namespace llvm;
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static bool StripSymbolTable(SymbolTable &SymTab) {
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bool RemovedSymbol = false;
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for (SymbolTable::iterator I = SymTab.begin(); I != SymTab.end();) {
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// Removing items from the plane can cause the plane itself to get deleted.
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// If this happens, make sure we incremented our plane iterator already!
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std::map<const std::string, Value *> &Plane = (I++)->second;
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SymbolTable::type_iterator B = Plane.begin(), Bend = Plane.end();
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while (B != Bend) { // Found nonempty type plane!
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Value *V = B->second;
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if (isa<Constant>(V) || isa<Type>(V)) {
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SymTab.type_remove(B++);
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RemovedSymbol = true;
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} else {
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++B;
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if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasInternalLinkage()){
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// Set name to "", removing from symbol table!
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V->setName("", &SymTab);
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RemovedSymbol = true;
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}
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}
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}
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}
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return RemovedSymbol;
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}
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namespace {
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struct SymbolStripping : public FunctionPass {
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virtual bool runOnFunction(Function &F) {
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return StripSymbolTable(F.getSymbolTable());
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}
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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}
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};
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RegisterOpt<SymbolStripping> X("strip", "Strip symbols from functions");
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struct FullSymbolStripping : public SymbolStripping {
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virtual bool doInitialization(Module &M) {
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return StripSymbolTable(M.getSymbolTable());
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}
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};
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RegisterOpt<FullSymbolStripping> Y("mstrip",
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"Strip symbols from module and functions");
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}
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Pass *llvm::createSymbolStrippingPass() {
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return new SymbolStripping();
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}
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Pass *llvm::createFullSymbolStrippingPass() {
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return new FullSymbolStripping();
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}
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