//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-// This file implements stripping symbols out of symbol tables.
+// The StripSymbols transformation implements code stripping. Specifically, it
+// can delete:
+//
+// * names for virtual registers
+// * symbols for internal globals and functions
+// * debug information
//
-// Specifically, this allows you to strip all of the symbols out of:
-// * All functions in a module
-// * All non-essential symbols in a module (all function symbols + all module
-// scope symbols)
-// * Debug information.
-//
-// 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).
+// 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/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
+#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
+#include "llvm/Analysis/DebugInfo.h"
#include "llvm/ValueSymbolTable.h"
#include "llvm/TypeSymbolTable.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
namespace {
- class VISIBILITY_HIDDEN StripSymbols : public ModulePass {
+ class StripSymbols : public ModulePass {
bool OnlyDebugInfo;
public:
static char ID; // Pass identification, replacement for typeid
- StripSymbols(bool ODI = false)
- : ModulePass((intptr_t)&ID), OnlyDebugInfo(ODI) {}
+ explicit StripSymbols(bool ODI = false)
+ : ModulePass(&ID), OnlyDebugInfo(ODI) {}
virtual bool runOnModule(Module &M);
}
};
- char StripSymbols::ID = 0;
- RegisterPass<StripSymbols> X("strip", "Strip all symbols from a module");
+ class StripNonDebugSymbols : public ModulePass {
+ public:
+ static char ID; // Pass identification, replacement for typeid
+ explicit StripNonDebugSymbols()
+ : ModulePass(&ID) {}
+
+ 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) {}
+
+ virtual bool runOnModule(Module &M);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ }
+ };
}
+char StripSymbols::ID = 0;
+static RegisterPass<StripSymbols>
+X("strip", "Strip all symbols from a module");
+
ModulePass *llvm::createStripSymbolsPass(bool OnlyDebugInfo) {
return new StripSymbols(OnlyDebugInfo);
}
+char StripNonDebugSymbols::ID = 0;
+static RegisterPass<StripNonDebugSymbols>
+Y("strip-nondebug", "Strip all symbols, except dbg symbols, from a module");
+
+ModulePass *llvm::createStripNonDebugSymbolsPass() {
+ return new StripNonDebugSymbols();
+}
+
+char StripDebugDeclare::ID = 0;
+static RegisterPass<StripDebugDeclare>
+Z("strip-debug-declare", "Strip all llvm.dbg.declare intrinsics");
+
+ModulePass *llvm::createStripDebugDeclarePass() {
+ return new StripDebugDeclare();
+}
+
+/// 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!");
- std::vector<Constant*> Operands;
+ SmallPtrSet<Constant *, 4> Operands;
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
if (isa<DerivedType>(C->getOperand(i)->getType()) &&
- C->getOperand(i)->hasOneUse())
- Operands.push_back(C->getOperand(i));
+ OnlyUsedBy(C->getOperand(i), C))
+ Operands.insert(C->getOperand(i));
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
- if (!GV->hasInternalLinkage()) return; // Don't delete non static globals.
+ if (!GV->hasLocalLinkage()) return; // Don't delete non static globals.
GV->eraseFromParent();
}
else if (!isa<Function>(C))
- C->destroyConstant();
+ if (isa<CompositeType>(C->getType()))
+ C->destroyConstant();
// If the constant referenced anything, see if we can delete it as well.
- while (!Operands.empty()) {
- RemoveDeadConstant(Operands.back());
- Operands.pop_back();
- }
+ 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) {
+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)->hasInternalLinkage()) {
- // Set name to "", removing from symbol table!
- V->setName("");
+ 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 the symbol table of its names.
-static void StripTypeSymtab(TypeSymbolTable &ST) {
- for (TypeSymbolTable::iterator TI = ST.begin(), E = ST.end(); TI != E; )
- ST.remove(TI++);
+static void StripTypeSymtab(TypeSymbolTable &ST, bool PreserveDbgInfo) {
+ for (TypeSymbolTable::iterator TI = ST.begin(), E = ST.end(); TI != E; ) {
+ if (PreserveDbgInfo && strncmp(TI->first.c_str(), "llvm.dbg", 8) == 0)
+ ++TI;
+ else
+ ST.remove(TI++);
+ }
}
+/// 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) {
-bool StripSymbols::runOnModule(Module &M) {
- // If we're not just stripping debug info, strip all symbols from the
- // functions and the names from any internal globals.
- if (!OnlyDebugInfo) {
- for (Module::global_iterator I = M.global_begin(), E = M.global_end();
- I != E; ++I)
- if (I->hasInternalLinkage())
- I->setName(""); // Internal symbols can't participate in linkage
+ SmallPtrSet<const GlobalValue*, 8> llvmUsedValues;
+ findUsedValues(M.getGlobalVariable("llvm.used"), llvmUsedValues);
+ findUsedValues(M.getGlobalVariable("llvm.compiler.used"), llvmUsedValues);
- for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
- if (I->hasInternalLinkage())
+ 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
- StripSymtab(I->getValueSymbolTable());
- }
-
- // Remove all names from types.
- StripTypeSymtab(M.getTypeSymbolTable());
}
+
+ 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.
+ StripTypeSymtab(M.getTypeSymbolTable(), 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) {
- // 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.
+ // Remove all of the calls to the debugger intrinsics, and remove them from
+ // the module.
Function *FuncStart = M.getFunction("llvm.dbg.func.start");
Function *StopPoint = M.getFunction("llvm.dbg.stoppoint");
Function *RegionStart = M.getFunction("llvm.dbg.region.start");
Function *RegionEnd = M.getFunction("llvm.dbg.region.end");
Function *Declare = M.getFunction("llvm.dbg.declare");
- if (!FuncStart && !StopPoint && !RegionStart && !RegionEnd && !Declare)
- return true;
-
- std::vector<GlobalVariable*> DeadGlobals;
- // Remove all of the calls to the debugger intrinsics, and remove them from
- // the module.
if (FuncStart) {
while (!FuncStart->use_empty()) {
CallInst *CI = cast<CallInst>(FuncStart->use_back());
- Value *Arg = CI->getOperand(1);
- assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
CI->eraseFromParent();
- if (Arg->use_empty())
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
- DeadGlobals.push_back(GV);
}
FuncStart->eraseFromParent();
}
if (StopPoint) {
while (!StopPoint->use_empty()) {
CallInst *CI = cast<CallInst>(StopPoint->use_back());
- Value *Arg = CI->getOperand(3);
- assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
CI->eraseFromParent();
- if (Arg->use_empty())
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
- DeadGlobals.push_back(GV);
}
StopPoint->eraseFromParent();
}
if (RegionStart) {
while (!RegionStart->use_empty()) {
CallInst *CI = cast<CallInst>(RegionStart->use_back());
- Value *Arg = CI->getOperand(1);
- assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
CI->eraseFromParent();
- if (Arg->use_empty())
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
- DeadGlobals.push_back(GV);
}
RegionStart->eraseFromParent();
}
if (RegionEnd) {
while (!RegionEnd->use_empty()) {
CallInst *CI = cast<CallInst>(RegionEnd->use_back());
- Value *Arg = CI->getOperand(1);
- assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
CI->eraseFromParent();
- if (Arg->use_empty())
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
- DeadGlobals.push_back(GV);
}
RegionEnd->eraseFromParent();
}
if (Declare) {
while (!Declare->use_empty()) {
CallInst *CI = cast<CallInst>(Declare->use_back());
- Value *Arg = CI->getOperand(2);
+ CI->eraseFromParent();
+ }
+ Declare->eraseFromParent();
+ }
+
+ NamedMDNode *NMD = M.getNamedMetadata("llvm.dbg.gv");
+ if (NMD)
+ NMD->eraseFromParent();
+
+ // Remove dead metadata.
+ M.getContext().RemoveDeadMetadata();
+ return true;
+}
+
+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->getOperand(1);
+ Value *Arg2 = CI->getOperand(2);
assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
CI->eraseFromParent();
- if (Arg->use_empty())
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
- DeadGlobals.push_back(GV);
+ 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();
}
- // Finally, delete any internal globals that were only used by the debugger
- // intrinsics.
- while (!DeadGlobals.empty()) {
- GlobalVariable *GV = DeadGlobals.back();
- DeadGlobals.pop_back();
- if (GV->hasInternalLinkage())
- RemoveDeadConstant(GV);
+ // Delete all llvm.dbg.global_variables.
+ for (Module::global_iterator I = M.global_begin(), E = M.global_end();
+ I != E; ++I) {
+ GlobalVariable *GV = dyn_cast<GlobalVariable>(I);
+ if (!GV) continue;
+ if (GV->use_empty() && GV->getName().startswith("llvm.dbg.global_variable"))
+ DeadConstants.push_back(GV);
+ }
+
+ 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;
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