1 files changed, 414 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Transforms/IPO/StripSymbols.cpp b/contrib/llvm/lib/Transforms/IPO/StripSymbols.cpp
new file mode 100644
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+++ b/contrib/llvm/lib/Transforms/IPO/StripSymbols.cpp
@@ -0,0 +1,414 @@
+//===- StripSymbols.cpp - Strip symbols and debug info from a module ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// The StripSymbols transformation implements code stripping. Specifically, it
+// can delete:
+// 
+//   * names for virtual registers
+//   * symbols for internal globals and functions
+//   * debug information
+//
+// Note that this transformation 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 or making it harder to reverse engineer code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Constants.h"
+#include "llvm/DebugInfo.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/TypeFinder.h"
+#include "llvm/ValueSymbolTable.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+using namespace llvm;
+
+namespace {
+  class StripSymbols : public ModulePass {
+    bool OnlyDebugInfo;
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    explicit StripSymbols(bool ODI = false) 
+      : ModulePass(ID), OnlyDebugInfo(ODI) {
+        initializeStripSymbolsPass(*PassRegistry::getPassRegistry());
+      }
+
+    virtual bool runOnModule(Module &M);
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+    }
+  };
+
+  class StripNonDebugSymbols : public ModulePass {
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    explicit StripNonDebugSymbols()
+      : ModulePass(ID) {
+        initializeStripNonDebugSymbolsPass(*PassRegistry::getPassRegistry());
+      }
+
+    virtual bool runOnModule(Module &M);
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+    }
+  };
+
+  class StripDebugDeclare : public ModulePass {
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    explicit StripDebugDeclare()
+      : ModulePass(ID) {
+        initializeStripDebugDeclarePass(*PassRegistry::getPassRegistry());
+      }
+
+    virtual bool runOnModule(Module &M);
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+    }
+  };
+
+  class StripDeadDebugInfo : public ModulePass {
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    explicit StripDeadDebugInfo()
+      : ModulePass(ID) {
+        initializeStripDeadDebugInfoPass(*PassRegistry::getPassRegistry());
+      }
+
+    virtual bool runOnModule(Module &M);
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+    }
+  };
+}
+
+char StripSymbols::ID = 0;
+INITIALIZE_PASS(StripSymbols, "strip",
+                "Strip all symbols from a module", false, false)
+
+ModulePass *llvm::createStripSymbolsPass(bool OnlyDebugInfo) {
+  return new StripSymbols(OnlyDebugInfo);
+}
+
+char StripNonDebugSymbols::ID = 0;
+INITIALIZE_PASS(StripNonDebugSymbols, "strip-nondebug",
+                "Strip all symbols, except dbg symbols, from a module",
+                false, false)
+
+ModulePass *llvm::createStripNonDebugSymbolsPass() {
+  return new StripNonDebugSymbols();
+}
+
+char StripDebugDeclare::ID = 0;
+INITIALIZE_PASS(StripDebugDeclare, "strip-debug-declare",
+                "Strip all llvm.dbg.declare intrinsics", false, false)
+
+ModulePass *llvm::createStripDebugDeclarePass() {
+  return new StripDebugDeclare();
+}
+
+char StripDeadDebugInfo::ID = 0;
+INITIALIZE_PASS(StripDeadDebugInfo, "strip-dead-debug-info",
+                "Strip debug info for unused symbols", false, false)
+
+ModulePass *llvm::createStripDeadDebugInfoPass() {
+  return new StripDeadDebugInfo();
+}
+
+/// OnlyUsedBy - Return true if V is only used by Usr.
+static bool OnlyUsedBy(Value *V, Value *Usr) {
+  for(Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
+    User *U = *I;
+    if (U != Usr)
+      return false;
+  }
+  return true;
+}
+
+static void RemoveDeadConstant(Constant *C) {
+  assert(C->use_empty() && "Constant is not dead!");
+  SmallPtrSet<Constant*, 4> Operands;
+  for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
+    if (OnlyUsedBy(C->getOperand(i), C)) 
+      Operands.insert(cast<Constant>(C->getOperand(i)));
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
+    if (!GV->hasLocalLinkage()) return;   // Don't delete non static globals.
+    GV->eraseFromParent();
+  }
+  else if (!isa<Function>(C))
+    if (isa<CompositeType>(C->getType()))
+      C->destroyConstant();
+
+  // If the constant referenced anything, see if we can delete it as well.
+  for (SmallPtrSet<Constant*, 4>::iterator OI = Operands.begin(),
+         OE = Operands.end(); OI != OE; ++OI)
+    RemoveDeadConstant(*OI);
+}
+
+// Strip the symbol table of its names.
+//
+static void StripSymtab(ValueSymbolTable &ST, bool PreserveDbgInfo) {
+  for (ValueSymbolTable::iterator VI = ST.begin(), VE = ST.end(); VI != VE; ) {
+    Value *V = VI->getValue();
+    ++VI;
+    if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasLocalLinkage()) {
+      if (!PreserveDbgInfo || !V->getName().startswith("llvm.dbg"))
+        // Set name to "", removing from symbol table!
+        V->setName("");
+    }
+  }
+}
+
+// Strip any named types of their names.
+static void StripTypeNames(Module &M, bool PreserveDbgInfo) {
+  TypeFinder StructTypes;
+  StructTypes.run(M, false);
+
+  for (unsigned i = 0, e = StructTypes.size(); i != e; ++i) {
+    StructType *STy = StructTypes[i];
+    if (STy->isLiteral() || STy->getName().empty()) continue;
+    
+    if (PreserveDbgInfo && STy->getName().startswith("llvm.dbg"))
+      continue;
+
+    STy->setName("");
+  }
+}
+
+/// Find values that are marked as llvm.used.
+static void findUsedValues(GlobalVariable *LLVMUsed,
+                           SmallPtrSet<const GlobalValue*, 8> &UsedValues) {
+  if (LLVMUsed == 0) return;
+  UsedValues.insert(LLVMUsed);
+  
+  ConstantArray *Inits = dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
+  if (Inits == 0) return;
+  
+  for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
+    if (GlobalValue *GV = 
+          dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
+      UsedValues.insert(GV);
+}
+
+/// StripSymbolNames - Strip symbol names.
+static bool StripSymbolNames(Module &M, bool PreserveDbgInfo) {
+
+  SmallPtrSet<const GlobalValue*, 8> llvmUsedValues;
+  findUsedValues(M.getGlobalVariable("llvm.used"), llvmUsedValues);
+  findUsedValues(M.getGlobalVariable("llvm.compiler.used"), llvmUsedValues);
+
+  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
+    if (I->hasLocalLinkage() && llvmUsedValues.count(I) == 0)
+      if (!PreserveDbgInfo || !I->getName().startswith("llvm.dbg"))
+        I->setName("");     // Internal symbols can't participate in linkage
+  }
+  
+  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
+    if (I->hasLocalLinkage() && llvmUsedValues.count(I) == 0)
+      if (!PreserveDbgInfo || !I->getName().startswith("llvm.dbg"))
+        I->setName("");     // Internal symbols can't participate in linkage
+    StripSymtab(I->getValueSymbolTable(), PreserveDbgInfo);
+  }
+  
+  // Remove all names from types.
+  StripTypeNames(M, PreserveDbgInfo);
+
+  return true;
+}
+
+// StripDebugInfo - Strip debug info in the module if it exists.  
+// To do this, we remove llvm.dbg.func.start, llvm.dbg.stoppoint, and 
+// llvm.dbg.region.end calls, and any globals they point to if now dead.
+static bool StripDebugInfo(Module &M) {
+
+  bool Changed = false;
+
+  // Remove all of the calls to the debugger intrinsics, and remove them from
+  // the module.
+  if (Function *Declare = M.getFunction("llvm.dbg.declare")) {
+    while (!Declare->use_empty()) {
+      CallInst *CI = cast<CallInst>(Declare->use_back());
+      CI->eraseFromParent();
+    }
+    Declare->eraseFromParent();
+    Changed = true;
+  }
+
+  if (Function *DbgVal = M.getFunction("llvm.dbg.value")) {
+    while (!DbgVal->use_empty()) {
+      CallInst *CI = cast<CallInst>(DbgVal->use_back());
+      CI->eraseFromParent();
+    }
+    DbgVal->eraseFromParent();
+    Changed = true;
+  }
+
+  for (Module::named_metadata_iterator NMI = M.named_metadata_begin(),
+         NME = M.named_metadata_end(); NMI != NME;) {
+    NamedMDNode *NMD = NMI;
+    ++NMI;
+    if (NMD->getName().startswith("llvm.dbg.")) {
+      NMD->eraseFromParent();
+      Changed = true;
+    }
+  }
+
+  for (Module::iterator MI = M.begin(), ME = M.end(); MI != ME; ++MI)
+    for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE;
+         ++FI)
+      for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); BI != BE;
+           ++BI) {
+        if (!BI->getDebugLoc().isUnknown()) {
+          Changed = true;
+          BI->setDebugLoc(DebugLoc());
+        }
+      }
+
+  return Changed;
+}
+
+bool StripSymbols::runOnModule(Module &M) {
+  bool Changed = false;
+  Changed |= StripDebugInfo(M);
+  if (!OnlyDebugInfo)
+    Changed |= StripSymbolNames(M, false);
+  return Changed;
+}
+
+bool StripNonDebugSymbols::runOnModule(Module &M) {
+  return StripSymbolNames(M, true);
+}
+
+bool StripDebugDeclare::runOnModule(Module &M) {
+
+  Function *Declare = M.getFunction("llvm.dbg.declare");
+  std::vector<Constant*> DeadConstants;
+
+  if (Declare) {
+    while (!Declare->use_empty()) {
+      CallInst *CI = cast<CallInst>(Declare->use_back());
+      Value *Arg1 = CI->getArgOperand(0);
+      Value *Arg2 = CI->getArgOperand(1);
+      assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
+      CI->eraseFromParent();
+      if (Arg1->use_empty()) {
+        if (Constant *C = dyn_cast<Constant>(Arg1)) 
+          DeadConstants.push_back(C);
+        else 
+          RecursivelyDeleteTriviallyDeadInstructions(Arg1);
+      }
+      if (Arg2->use_empty())
+        if (Constant *C = dyn_cast<Constant>(Arg2)) 
+          DeadConstants.push_back(C);
+    }
+    Declare->eraseFromParent();
+  }
+
+  while (!DeadConstants.empty()) {
+    Constant *C = DeadConstants.back();
+    DeadConstants.pop_back();
+    if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
+      if (GV->hasLocalLinkage())
+        RemoveDeadConstant(GV);
+    } else
+      RemoveDeadConstant(C);
+  }
+
+  return true;
+}
+
+/// getRealLinkageName - If special LLVM prefix that is used to inform the asm 
+/// printer to not emit usual symbol prefix before the symbol name is used then
+/// return linkage name after skipping this special LLVM prefix.
+static StringRef getRealLinkageName(StringRef LinkageName) {
+  char One = '\1';
+  if (LinkageName.startswith(StringRef(&One, 1)))
+    return LinkageName.substr(1);
+  return LinkageName;
+}
+
+bool StripDeadDebugInfo::runOnModule(Module &M) {
+  bool Changed = false;
+
+  // Debugging infomration is encoded in llvm IR using metadata. This is designed
+  // such a way that debug info for symbols preserved even if symbols are
+  // optimized away by the optimizer. This special pass removes debug info for 
+  // such symbols.
+
+  // llvm.dbg.gv keeps track of debug info for global variables.
+  if (NamedMDNode *NMD = M.getNamedMetadata("llvm.dbg.gv")) {
+    SmallVector<MDNode *, 8> MDs;
+    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
+      if (DIGlobalVariable(NMD->getOperand(i)).Verify())
+        MDs.push_back(NMD->getOperand(i));
+      else
+        Changed = true;
+    NMD->eraseFromParent();
+    NMD = NULL;
+
+    for (SmallVector<MDNode *, 8>::iterator I = MDs.begin(),
+           E = MDs.end(); I != E; ++I) {
+      GlobalVariable *GV = DIGlobalVariable(*I).getGlobal();
+      if (GV && M.getGlobalVariable(GV->getName(), true)) {
+        if (!NMD)
+          NMD = M.getOrInsertNamedMetadata("llvm.dbg.gv");
+        NMD->addOperand(*I);
+      }
+      else
+        Changed = true;
+    }
+  }
+
+  // llvm.dbg.sp keeps track of debug info for subprograms.
+  if (NamedMDNode *NMD = M.getNamedMetadata("llvm.dbg.sp")) {
+    SmallVector<MDNode *, 8> MDs;
+    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
+      if (DISubprogram(NMD->getOperand(i)).Verify())
+        MDs.push_back(NMD->getOperand(i));
+      else
+        Changed = true;
+    NMD->eraseFromParent();
+    NMD = NULL;
+
+    for (SmallVector<MDNode *, 8>::iterator I = MDs.begin(),
+           E = MDs.end(); I != E; ++I) {
+      bool FnIsLive = false;
+      if (Function *F = DISubprogram(*I).getFunction())
+        if (M.getFunction(F->getName()))
+          FnIsLive = true;
+      if (FnIsLive) {
+          if (!NMD)
+            NMD = M.getOrInsertNamedMetadata("llvm.dbg.sp");
+          NMD->addOperand(*I);
+      } else {
+        // Remove llvm.dbg.lv.fnname named mdnode which may have been used
+        // to hold debug info for dead function's local variables.
+        StringRef FName = DISubprogram(*I).getLinkageName();
+        if (FName.empty())
+          FName = DISubprogram(*I).getName();
+        if (NamedMDNode *LVNMD = 
+            M.getNamedMetadata(Twine("llvm.dbg.lv.", 
+                                     getRealLinkageName(FName)))) 
+          LVNMD->eraseFromParent();
+      }
+    }
+  }
+
+  return Changed;
+}