//
// The StripSymbols transformation implements code stripping. Specifically, it
// can delete:
-//
+//
// * names for virtual registers
// * symbols for internal globals and functions
// * debug information
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Instructions.h"
-#include "llvm/Module.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/TypeFinder.h"
+#include "llvm/IR/ValueSymbolTable.h"
#include "llvm/Pass.h"
-#include "llvm/Analysis/DebugInfo.h"
-#include "llvm/ValueSymbolTable.h"
-#include "llvm/TypeSymbolTable.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
namespace {
bool OnlyDebugInfo;
public:
static char ID; // Pass identification, replacement for typeid
- explicit StripSymbols(bool ODI = false)
- : ModulePass(&ID), OnlyDebugInfo(ODI) {}
+ explicit StripSymbols(bool ODI = false)
+ : ModulePass(ID), OnlyDebugInfo(ODI) {
+ initializeStripSymbolsPass(*PassRegistry::getPassRegistry());
+ }
- virtual bool runOnModule(Module &M);
+ bool runOnModule(Module &M) override;
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
};
public:
static char ID; // Pass identification, replacement for typeid
explicit StripNonDebugSymbols()
- : ModulePass(&ID) {}
+ : ModulePass(ID) {
+ initializeStripNonDebugSymbolsPass(*PassRegistry::getPassRegistry());
+ }
- virtual bool runOnModule(Module &M);
+ bool runOnModule(Module &M) override;
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
};
public:
static char ID; // Pass identification, replacement for typeid
explicit StripDebugDeclare()
- : ModulePass(&ID) {}
+ : ModulePass(ID) {
+ initializeStripDebugDeclarePass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnModule(Module &M) override;
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ 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);
+ bool runOnModule(Module &M) override;
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
};
}
char StripSymbols::ID = 0;
-static RegisterPass<StripSymbols>
-X("strip", "Strip all symbols from a module");
+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;
-static RegisterPass<StripNonDebugSymbols>
-Y("strip-nondebug", "Strip all symbols, except dbg symbols, from a module");
+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;
-static RegisterPass<StripDebugDeclare>
-Z("strip-debug-declare", "Strip all llvm.dbg.declare intrinsics");
+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;
+ for (User *U : V->users())
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 (isa<DerivedType>(C->getOperand(i)->getType()) &&
- OnlyUsedBy(C->getOperand(i), C))
- Operands.insert(cast<Constant>(C->getOperand(i)));
+ for (Value *Op : C->operands())
+ if (OnlyUsedBy(Op, C))
+ Operands.insert(cast<Constant>(Op));
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
- if (!GV->hasLocalLinkage()) 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 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);
+ for (Constant *O : Operands)
+ RemoveDeadConstant(O);
}
// Strip the symbol table of its names.
}
}
-// Strip the symbol table of its names.
-static void StripTypeSymtab(TypeSymbolTable &ST, bool PreserveDbgInfo) {
- for (TypeSymbolTable::iterator TI = ST.begin(), E = ST.end(); TI != E; ) {
- if (PreserveDbgInfo && StringRef(TI->first).startswith("llvm.dbg"))
- ++TI;
- else
- ST.remove(TI++);
+// 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;
+ SmallPtrSetImpl<const GlobalValue*> &UsedValues) {
+ if (!LLVMUsed) return;
UsedValues.insert(LLVMUsed);
-
- ConstantArray *Inits = dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
- if (Inits == 0) return;
-
+
+ ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
+
for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
- if (GlobalValue *GV =
+ if (GlobalValue *GV =
dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
UsedValues.insert(GV);
}
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.
- 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) {
-
- 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;
- }
- NamedMDNode *NMD = M.getNamedMetadata("llvm.dbg.gv");
- if (NMD) {
- Changed = true;
- NMD->eraseFromParent();
- }
-
- NMD = M.getNamedMetadata("llvm.dbg.lv");
- if (NMD) {
- Changed = true;
- NMD->eraseFromParent();
- }
-
- unsigned MDDbgKind = M.getMDKindID("dbg");
- 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)
- BI->setMetadata(MDDbgKind, 0);
+ // Remove all names from types.
+ StripTypeNames(M, PreserveDbgInfo);
return true;
}
if (Declare) {
while (!Declare->use_empty()) {
- CallInst *CI = cast<CallInst>(Declare->use_back());
- Value *Arg1 = CI->getOperand(1);
- Value *Arg2 = CI->getOperand(2);
+ CallInst *CI = cast<CallInst>(Declare->user_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))
+ if (Constant *C = dyn_cast<Constant>(Arg1))
DeadConstants.push_back(C);
- else
+ else
RecursivelyDeleteTriviallyDeadInstructions(Arg1);
}
if (Arg2->use_empty())
- if (Constant *C = dyn_cast<Constant>(Arg2))
+ if (Constant *C = dyn_cast<Constant>(Arg2))
DeadConstants.push_back(C);
}
Declare->eraseFromParent();
return true;
}
+
+/// Remove any debug info for global variables/functions in the given module for
+/// which said global variable/function no longer exists (i.e. is null).
+///
+/// Debugging information 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.
+bool StripDeadDebugInfo::runOnModule(Module &M) {
+ bool Changed = false;
+
+ LLVMContext &C = M.getContext();
+
+ // Find all debug info in F. This is actually overkill in terms of what we
+ // want to do, but we want to try and be as resilient as possible in the face
+ // of potential debug info changes by using the formal interfaces given to us
+ // as much as possible.
+ DebugInfoFinder F;
+ F.processModule(M);
+
+ // For each compile unit, find the live set of global variables/functions and
+ // replace the current list of potentially dead global variables/functions
+ // with the live list.
+ SmallVector<Metadata *, 64> LiveGlobalVariables;
+ SmallVector<Metadata *, 64> LiveSubprograms;
+ DenseSet<const MDNode *> VisitedSet;
+
+ for (DICompileUnit *DIC : F.compile_units()) {
+ // Create our live subprogram list.
+ bool SubprogramChange = false;
+ for (DISubprogram *DISP : DIC->getSubprograms()) {
+ // Make sure we visit each subprogram only once.
+ if (!VisitedSet.insert(DISP).second)
+ continue;
+
+ // If the function referenced by DISP is not null, the function is live.
+ if (DISP->getFunction())
+ LiveSubprograms.push_back(DISP);
+ else
+ SubprogramChange = true;
+ }
+
+ // Create our live global variable list.
+ bool GlobalVariableChange = false;
+ for (DIGlobalVariable *DIG : DIC->getGlobalVariables()) {
+ // Make sure we only visit each global variable only once.
+ if (!VisitedSet.insert(DIG).second)
+ continue;
+
+ // If the global variable referenced by DIG is not null, the global
+ // variable is live.
+ if (DIG->getVariable())
+ LiveGlobalVariables.push_back(DIG);
+ else
+ GlobalVariableChange = true;
+ }
+
+ // If we found dead subprograms or global variables, replace the current
+ // subprogram list/global variable list with our new live subprogram/global
+ // variable list.
+ if (SubprogramChange) {
+ DIC->replaceSubprograms(MDTuple::get(C, LiveSubprograms));
+ Changed = true;
+ }
+
+ if (GlobalVariableChange) {
+ DIC->replaceGlobalVariables(MDTuple::get(C, LiveGlobalVariables));
+ Changed = true;
+ }
+
+ // Reset lists for the next iteration.
+ LiveSubprograms.clear();
+ LiveGlobalVariables.clear();
+ }
+
+ return Changed;
+}
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