StripSymbols.cpp revision c86b67742a3298c0a5a715b57a64f11107b8a3f2
1e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner//===- StripSymbols.cpp - Strip symbols and debug info from a module ------===// 2fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 3e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner// The LLVM Compiler Infrastructure 4e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner// 5e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner// This file was developed by the LLVM research group and is distributed under 6e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner// the University of Illinois Open Source License. See LICENSE.TXT for details. 7fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 8e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner//===----------------------------------------------------------------------===// 9e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner// 10c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// The StripSymbols transformation implements code stripping. Specifically, it 11c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// can delete: 12c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// 13c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// * names for virtual registers 14c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// * symbols for internal globals and functions 15c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// * debug information 16e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner// 17c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// Note that this transformation makes code much less readable, so it should 18c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// only be used in situations where the 'strip' utility would be used, such as 19c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// reducing code size or making it harder to reverse engineer code. 20e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner// 21e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner//===----------------------------------------------------------------------===// 22e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 23e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner#include "llvm/Transforms/IPO.h" 24dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner#include "llvm/Constants.h" 25dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner#include "llvm/DerivedTypes.h" 26dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner#include "llvm/Instructions.h" 27e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner#include "llvm/Module.h" 28e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner#include "llvm/Pass.h" 29ef9b9a793949469cdaa4ab6d0173136229dcab7bReid Spencer#include "llvm/ValueSymbolTable.h" 3078d033e086e19e016273de014f9214aa6f3f844bReid Spencer#include "llvm/TypeSymbolTable.h" 319133fe28954d498fc4de13064c7d65bd811de02cReid Spencer#include "llvm/Support/Compiler.h" 32e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattnerusing namespace llvm; 33e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 34e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattnernamespace { 359133fe28954d498fc4de13064c7d65bd811de02cReid Spencer class VISIBILITY_HIDDEN StripSymbols : public ModulePass { 36e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner bool OnlyDebugInfo; 37e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner public: 38ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 39c2bbfc18e9adbbdcf5b3375d8d25e2452f7df7f1Dan Gohman explicit StripSymbols(bool ODI = false) 40794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel : ModulePass((intptr_t)&ID), OnlyDebugInfo(ODI) {} 41e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 42e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner virtual bool runOnModule(Module &M); 43e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 44e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 45e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner AU.setPreservesAll(); 46e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner } 47e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner }; 48794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 491997473cf72957d0e70322e2fe6fe2ab141c58a6Devang Patel char StripSymbols::ID = 0; 507f8897f22e88271cfa114998a4d6088e7c8e8e11Chris Lattner RegisterPass<StripSymbols> X("strip", "Strip all symbols from a module"); 51e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner} 52e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 53e3ad43c828280cf11e8631f1a814a51a0b168016Chris LattnerModulePass *llvm::createStripSymbolsPass(bool OnlyDebugInfo) { 54e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner return new StripSymbols(OnlyDebugInfo); 55e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner} 56e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 57dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattnerstatic void RemoveDeadConstant(Constant *C) { 58dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner assert(C->use_empty() && "Constant is not dead!"); 59dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner std::vector<Constant*> Operands; 60dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) 61dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (isa<DerivedType>(C->getOperand(i)->getType()) && 62dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner C->getOperand(i)->hasOneUse()) 63dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner Operands.push_back(C->getOperand(i)); 64dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) { 65dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (!GV->hasInternalLinkage()) return; // Don't delete non static globals. 66dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner GV->eraseFromParent(); 67dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 68dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner else if (!isa<Function>(C)) 69dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner C->destroyConstant(); 70fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 71dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // If the constant referenced anything, see if we can delete it as well. 72dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner while (!Operands.empty()) { 73dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner RemoveDeadConstant(Operands.back()); 74dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner Operands.pop_back(); 75dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 76dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner} 77e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 787f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner// Strip the symbol table of its names. 797f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner// 807f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattnerstatic void StripSymtab(ValueSymbolTable &ST) { 817f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner for (ValueSymbolTable::iterator VI = ST.begin(), VE = ST.end(); VI != VE; ) { 82dec628eead87b20773c98a00830580df211acc98Chris Lattner Value *V = VI->getValue(); 837f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner ++VI; 847f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasInternalLinkage()) { 857f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner // Set name to "", removing from symbol table! 867f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner V->setName(""); 877f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner } 887f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner } 897f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner} 907f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner 917f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner// Strip the symbol table of its names. 927f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattnerstatic void StripTypeSymtab(TypeSymbolTable &ST) { 937f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner for (TypeSymbolTable::iterator TI = ST.begin(), E = ST.end(); TI != E; ) 947f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner ST.remove(TI++); 957f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner} 967f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner 977f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner 987f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner 99e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattnerbool StripSymbols::runOnModule(Module &M) { 100e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner // If we're not just stripping debug info, strip all symbols from the 101e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner // functions and the names from any internal globals. 102e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner if (!OnlyDebugInfo) { 1037f8897f22e88271cfa114998a4d6088e7c8e8e11Chris Lattner for (Module::global_iterator I = M.global_begin(), E = M.global_end(); 1047f8897f22e88271cfa114998a4d6088e7c8e8e11Chris Lattner I != E; ++I) 105e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner if (I->hasInternalLinkage()) 106e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner I->setName(""); // Internal symbols can't participate in linkage 107e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 108e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) { 109e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner if (I->hasInternalLinkage()) 110e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner I->setName(""); // Internal symbols can't participate in linkage 1117f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner StripSymtab(I->getValueSymbolTable()); 112e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner } 113b2f6c0075cc1aafce3c83a756242f148429ade0fChris Lattner 114b2f6c0075cc1aafce3c83a756242f148429ade0fChris Lattner // Remove all names from types. 1157f1444bc0aefdd924e9b231e20d4c0529311e141Chris Lattner StripTypeSymtab(M.getTypeSymbolTable()); 116e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner } 117e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner 118dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // Strip debug info in the module if it exists. To do this, we remove 119dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // llvm.dbg.func.start, llvm.dbg.stoppoint, and llvm.dbg.region.end calls, and 120dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // any globals they point to if now dead. 121688b0490e22eb67623f5aaa24406209be74efcb2Reid Spencer Function *FuncStart = M.getFunction("llvm.dbg.func.start"); 122688b0490e22eb67623f5aaa24406209be74efcb2Reid Spencer Function *StopPoint = M.getFunction("llvm.dbg.stoppoint"); 123688b0490e22eb67623f5aaa24406209be74efcb2Reid Spencer Function *RegionStart = M.getFunction("llvm.dbg.region.start"); 124688b0490e22eb67623f5aaa24406209be74efcb2Reid Spencer Function *RegionEnd = M.getFunction("llvm.dbg.region.end"); 125688b0490e22eb67623f5aaa24406209be74efcb2Reid Spencer Function *Declare = M.getFunction("llvm.dbg.declare"); 1264ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (!FuncStart && !StopPoint && !RegionStart && !RegionEnd && !Declare) 127dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner return true; 128dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner 129dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner std::vector<GlobalVariable*> DeadGlobals; 130dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner 131dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // Remove all of the calls to the debugger intrinsics, and remove them from 132dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // the module. 133dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (FuncStart) { 134dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner while (!FuncStart->use_empty()) { 135dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner CallInst *CI = cast<CallInst>(FuncStart->use_back()); 136dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner Value *Arg = CI->getOperand(1); 1374ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey assert(CI->use_empty() && "llvm.dbg intrinsic should have void result"); 138dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner CI->eraseFromParent(); 139dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (Arg->use_empty()) 140dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg)) 141dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner DeadGlobals.push_back(GV); 142dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 143dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner FuncStart->eraseFromParent(); 144dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 145dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (StopPoint) { 146dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner while (!StopPoint->use_empty()) { 147dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner CallInst *CI = cast<CallInst>(StopPoint->use_back()); 148f4321a3a438833dade457e24da6e1e6907cabcd5Jim Laskey Value *Arg = CI->getOperand(3); 1494ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey assert(CI->use_empty() && "llvm.dbg intrinsic should have void result"); 150dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner CI->eraseFromParent(); 151dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (Arg->use_empty()) 152dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg)) 153dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner DeadGlobals.push_back(GV); 154dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 155dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner StopPoint->eraseFromParent(); 156dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 1574ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (RegionStart) { 1584ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey while (!RegionStart->use_empty()) { 1594ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey CallInst *CI = cast<CallInst>(RegionStart->use_back()); 1604ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey Value *Arg = CI->getOperand(1); 1614ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey assert(CI->use_empty() && "llvm.dbg intrinsic should have void result"); 1624ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey CI->eraseFromParent(); 1634ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (Arg->use_empty()) 1644ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg)) 1654ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey DeadGlobals.push_back(GV); 1664ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey } 1674ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey RegionStart->eraseFromParent(); 1684ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey } 169dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (RegionEnd) { 170dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner while (!RegionEnd->use_empty()) { 171dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner CallInst *CI = cast<CallInst>(RegionEnd->use_back()); 1724ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey Value *Arg = CI->getOperand(1); 1734ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey assert(CI->use_empty() && "llvm.dbg intrinsic should have void result"); 174dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner CI->eraseFromParent(); 1754ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (Arg->use_empty()) 1764ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg)) 1774ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey DeadGlobals.push_back(GV); 178dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 179dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner RegionEnd->eraseFromParent(); 180dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 1814ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (Declare) { 1824ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey while (!Declare->use_empty()) { 1834ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey CallInst *CI = cast<CallInst>(Declare->use_back()); 1844ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey Value *Arg = CI->getOperand(2); 1854ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey assert(CI->use_empty() && "llvm.dbg intrinsic should have void result"); 1864ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey CI->eraseFromParent(); 1874ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (Arg->use_empty()) 1884ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg)) 1894ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey DeadGlobals.push_back(GV); 1904ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey } 1914ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey Declare->eraseFromParent(); 1924ca9757a39a1bf3bd1264a77e52db62e02cc85fbJim Laskey } 193dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner 194dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // Finally, delete any internal globals that were only used by the debugger 195dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner // intrinsics. 196dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner while (!DeadGlobals.empty()) { 197dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner GlobalVariable *GV = DeadGlobals.back(); 198dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner DeadGlobals.pop_back(); 199dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner if (GV->hasInternalLinkage()) 200dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner RemoveDeadConstant(GV); 201dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner } 202dd0ecf67316d68940fda2733faacf73b8bd22ec6Chris Lattner 203fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman return true; 204e3ad43c828280cf11e8631f1a814a51a0b168016Chris Lattner} 205