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https://github.com/RPCS3/llvm-mirror.git
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53e199440e
llvm-svn: 21427
149 lines
5.1 KiB
C++
149 lines
5.1 KiB
C++
//===- StripSymbols.cpp - Strip symbols and debug info from a module ------===//
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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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// * Debug information.
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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/IPO.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Instructions.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/SymbolTable.h"
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using namespace llvm;
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namespace {
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class StripSymbols : public ModulePass {
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bool OnlyDebugInfo;
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public:
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StripSymbols(bool ODI = false) : OnlyDebugInfo(ODI) {}
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virtual bool runOnModule(Module &M);
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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<StripSymbols> X("strip", "Strip all symbols from a module");
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}
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ModulePass *llvm::createStripSymbolsPass(bool OnlyDebugInfo) {
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return new StripSymbols(OnlyDebugInfo);
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}
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static void RemoveDeadConstant(Constant *C) {
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assert(C->use_empty() && "Constant is not dead!");
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std::vector<Constant*> Operands;
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for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
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if (isa<DerivedType>(C->getOperand(i)->getType()) &&
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C->getOperand(i)->hasOneUse())
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Operands.push_back(C->getOperand(i));
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if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
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if (!GV->hasInternalLinkage()) return; // Don't delete non static globals.
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GV->eraseFromParent();
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}
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else if (!isa<Function>(C))
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C->destroyConstant();
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// If the constant referenced anything, see if we can delete it as well.
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while (!Operands.empty()) {
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RemoveDeadConstant(Operands.back());
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Operands.pop_back();
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}
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}
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bool StripSymbols::runOnModule(Module &M) {
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// If we're not just stripping debug info, strip all symbols from the
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// functions and the names from any internal globals.
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if (!OnlyDebugInfo) {
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for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
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if (I->hasInternalLinkage())
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I->setName(""); // Internal symbols can't participate in linkage
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
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if (I->hasInternalLinkage())
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I->setName(""); // Internal symbols can't participate in linkage
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I->getSymbolTable().strip();
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}
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}
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// Strip debug info in the module if it exists. To do this, we remove
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// llvm.dbg.func.start, llvm.dbg.stoppoint, and llvm.dbg.region.end calls, and
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// any globals they point to if now dead.
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Function *FuncStart = M.getNamedFunction("llvm.dbg.func.start");
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Function *StopPoint = M.getNamedFunction("llvm.dbg.stoppoint");
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Function *RegionEnd = M.getNamedFunction("llvm.dbg.region.end");
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if (!FuncStart && !StopPoint && !RegionEnd)
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return true;
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std::vector<GlobalVariable*> DeadGlobals;
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// Remove all of the calls to the debugger intrinsics, and remove them from
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// the module.
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if (FuncStart) {
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Value *RV = UndefValue::get(StopPoint->getFunctionType()->getReturnType());
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while (!FuncStart->use_empty()) {
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CallInst *CI = cast<CallInst>(FuncStart->use_back());
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Value *Arg = CI->getOperand(1);
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CI->replaceAllUsesWith(RV);
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CI->eraseFromParent();
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if (Arg->use_empty())
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if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
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DeadGlobals.push_back(GV);
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}
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FuncStart->eraseFromParent();
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}
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if (StopPoint) {
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Value *RV = UndefValue::get(StopPoint->getFunctionType()->getReturnType());
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while (!StopPoint->use_empty()) {
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CallInst *CI = cast<CallInst>(StopPoint->use_back());
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Value *Arg = CI->getOperand(4);
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CI->replaceAllUsesWith(RV);
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CI->eraseFromParent();
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if (Arg->use_empty())
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if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
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DeadGlobals.push_back(GV);
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}
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StopPoint->eraseFromParent();
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}
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if (RegionEnd) {
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Value *RV = UndefValue::get(RegionEnd->getFunctionType()->getReturnType());
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while (!RegionEnd->use_empty()) {
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CallInst *CI = cast<CallInst>(RegionEnd->use_back());
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CI->replaceAllUsesWith(RV);
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CI->eraseFromParent();
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}
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RegionEnd->eraseFromParent();
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}
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// Finally, delete any internal globals that were only used by the debugger
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// intrinsics.
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while (!DeadGlobals.empty()) {
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GlobalVariable *GV = DeadGlobals.back();
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DeadGlobals.pop_back();
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if (GV->hasInternalLinkage())
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RemoveDeadConstant(GV);
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}
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return true;
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}
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