#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
+#include "llvm/Metadata.h"
+#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/CFG.h"
-#include "llvm/Support/Compiler.h"
#include <algorithm>
using namespace llvm;
STATISTIC(NumDeadAlloca, "Number of dead alloca's removed");
STATISTIC(NumPHIInsert, "Number of PHI nodes inserted");
-// Provide DenseMapInfo for all pointers.
namespace llvm {
template<>
struct DenseMapInfo<std::pair<BasicBlock*, unsigned> > {
static bool isEqual(const EltTy &LHS, const EltTy &RHS) {
return LHS == RHS;
}
- static bool isPod() { return true; }
};
}
return false; // Don't allow a store OF the AI, only INTO the AI.
if (SI->isVolatile())
return false;
- } else if (const BitCastInst *BC = dyn_cast<BitCastInst>(*UI)) {
- // A bitcast that does not feed into debug info inhibits promotion.
- if (!BC->hasOneUse() || !isa<DbgInfoIntrinsic>(*BC->use_begin()))
- return false;
- // If the only use is by debug info, this alloca will not exist in
- // non-debug code, so don't try to promote; this ensures the same
- // codegen with debug info. Otherwise, debug info should not
- // inhibit promotion (but we must examine other uses).
- if (AI->hasOneUse())
- return false;
} else {
return false;
}
return true;
}
+/// Finds the llvm.dbg.declare intrinsic describing V, if any.
+static DbgDeclareInst *findDbgDeclare(Value *V) {
+ if (MDNode *DebugNode = MDNode::getIfExists(V->getContext(), &V, 1))
+ for (Value::use_iterator UI = DebugNode->use_begin(),
+ E = DebugNode->use_end(); UI != E; ++UI)
+ if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(*UI))
+ return DDI;
+
+ return 0;
+}
+
namespace {
struct AllocaInfo;
// Data package used by RenamePass()
- class VISIBILITY_HIDDEN RenamePassData {
+ class RenamePassData {
public:
typedef std::vector<Value *> ValVector;
- RenamePassData() {}
+ RenamePassData() : BB(NULL), Pred(NULL), Values() {}
RenamePassData(BasicBlock *B, BasicBlock *P,
const ValVector &V) : BB(B), Pred(P), Values(V) {}
BasicBlock *BB;
///
/// This functionality is important because it avoids scanning large basic
/// blocks multiple times when promoting many allocas in the same block.
- class VISIBILITY_HIDDEN LargeBlockInfo {
+ class LargeBlockInfo {
/// InstNumbers - For each instruction that we track, keep the index of the
/// instruction. The index starts out as the number of the instruction from
/// the start of the block.
}
};
- struct VISIBILITY_HIDDEN PromoteMem2Reg {
+ struct PromoteMem2Reg {
/// Allocas - The alloca instructions being promoted.
///
std::vector<AllocaInst*> Allocas;
DominatorTree &DT;
DominanceFrontier &DF;
+ DIFactory *DIF;
/// AST - An AliasSetTracker object to update. If null, don't update it.
///
AliasSetTracker *AST;
-
+
/// AllocaLookup - Reverse mapping of Allocas.
///
std::map<AllocaInst*, unsigned> AllocaLookup;
///
std::vector<Value*> PointerAllocaValues;
+ /// AllocaDbgDeclares - For each alloca, we keep track of the dbg.declare
+ /// intrinsic that describes it, if any, so that we can convert it to a
+ /// dbg.value intrinsic if the alloca gets promoted.
+ SmallVector<DbgDeclareInst*, 8> AllocaDbgDeclares;
+
/// Visited - The set of basic blocks the renamer has already visited.
///
SmallPtrSet<BasicBlock*, 16> Visited;
public:
PromoteMem2Reg(const std::vector<AllocaInst*> &A, DominatorTree &dt,
DominanceFrontier &df, AliasSetTracker *ast)
- : Allocas(A), DT(dt), DF(df), AST(ast) {}
+ : Allocas(A), DT(dt), DF(df), DIF(0), AST(ast) {}
+ ~PromoteMem2Reg() {
+ if (DIF) delete DIF;
+ }
void run();
LargeBlockInfo &LBI);
void PromoteSingleBlockAlloca(AllocaInst *AI, AllocaInfo &Info,
LargeBlockInfo &LBI);
+ void ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI, StoreInst *SI,
+ uint64_t Offset);
void RenamePass(BasicBlock *BB, BasicBlock *Pred,
bool OnlyUsedInOneBlock;
Value *AllocaPointerVal;
+ DbgDeclareInst *DbgDeclare;
void clear() {
DefiningBlocks.clear();
OnlyBlock = 0;
OnlyUsedInOneBlock = true;
AllocaPointerVal = 0;
+ DbgDeclare = 0;
}
/// AnalyzeAlloca - Scan the uses of the specified alloca, filling in our
// As we scan the uses of the alloca instruction, keep track of stores,
// and decide whether all of the loads and stores to the alloca are within
// the same basic block.
- for (Value::use_iterator U = AI->use_begin(), E = AI->use_end();
- U != E;) {
- Instruction *User = cast<Instruction>(*U);
- ++U;
- if (BitCastInst *BC = dyn_cast<BitCastInst>(User)) {
- // Remove any uses of this alloca in DbgInfoInstrinsics.
- assert(BC->hasOneUse() && "Unexpected alloca uses!");
- DbgInfoIntrinsic *DI = cast<DbgInfoIntrinsic>(*BC->use_begin());
- DI->eraseFromParent();
- BC->eraseFromParent();
- continue;
- }
- else if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
+ for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
+ UI != E;) {
+ Instruction *User = cast<Instruction>(*UI++);
+
+ if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
// Remember the basic blocks which define new values for the alloca
DefiningBlocks.push_back(SI->getParent());
AllocaPointerVal = SI->getOperand(0);
OnlyUsedInOneBlock = false;
}
}
+
+ DbgDeclare = findDbgDeclare(AI);
}
};
} // end of anonymous namespace
Function &F = *DF.getRoot()->getParent();
if (AST) PointerAllocaValues.resize(Allocas.size());
+ AllocaDbgDeclares.resize(Allocas.size());
AllocaInfo Info;
LargeBlockInfo LBI;
// Finally, after the scan, check to see if the store is all that is left.
if (Info.UsingBlocks.empty()) {
+ // Record debuginfo for the store before removing it.
+ ConvertDebugDeclareToDebugValue(Info.DbgDeclare, Info.OnlyStore, 0);
// Remove the (now dead) store and alloca.
Info.OnlyStore->eraseFromParent();
LBI.deleteValue(Info.OnlyStore);
// Remove the (now dead) stores and alloca.
while (!AI->use_empty()) {
StoreInst *SI = cast<StoreInst>(AI->use_back());
+ // Record debuginfo for the store before removing it.
+ ConvertDebugDeclareToDebugValue(Info.DbgDeclare, SI, 0);
SI->eraseFromParent();
LBI.deleteValue(SI);
}
// stored into the alloca.
if (AST)
PointerAllocaValues[AllocaNum] = Info.AllocaPointerVal;
+
+ // Remember the dbg.declare intrinsic describing this alloca, if any.
+ if (Info.DbgDeclare) AllocaDbgDeclares[AllocaNum] = Info.DbgDeclare;
// Keep the reverse mapping of the 'Allocas' array for the rename pass.
AllocaLookup[Allocas[AllocaNum]] = AllocaNum;
//
std::vector<RenamePassData> RenamePassWorkList;
RenamePassWorkList.push_back(RenamePassData(F.begin(), 0, Values));
- while (!RenamePassWorkList.empty()) {
+ do {
RenamePassData RPD;
RPD.swap(RenamePassWorkList.back());
RenamePassWorkList.pop_back();
// RenamePass may add new worklist entries.
RenamePass(RPD.BB, RPD.Pred, RPD.Values, RenamePassWorkList);
- }
+ } while (!RenamePassWorkList.empty());
// The renamer uses the Visited set to avoid infinite loops. Clear it now.
Visited.clear();
PHINode *PN = I->second;
// If this PHI node merges one value and/or undefs, get the value.
- if (Value *V = PN->hasConstantValue(true)) {
- if (!isa<Instruction>(V) ||
- properlyDominates(cast<Instruction>(V), PN)) {
- if (AST && isa<PointerType>(PN->getType()))
- AST->deleteValue(PN);
- PN->replaceAllUsesWith(V);
- PN->eraseFromParent();
- NewPhiNodes.erase(I++);
- EliminatedAPHI = true;
- continue;
- }
+ if (Value *V = PN->hasConstantValue(&DT)) {
+ if (AST && isa<PointerType>(PN->getType()))
+ AST->deleteValue(PN);
+ PN->replaceAllUsesWith(V);
+ PN->eraseFromParent();
+ NewPhiNodes.erase(I++);
+ EliminatedAPHI = true;
+ continue;
}
++I;
}
LiveInBlockWorklist.pop_back();
--i, --e;
break;
- } else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+ }
+
+ if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (LI->getOperand(0) != AI) continue;
// Okay, we found a load before a store to the alloca. It is actually
}
// Otherwise, we *can* safely rewrite this load.
- LI->replaceAllUsesWith(OnlyStore->getOperand(0));
+ Value *ReplVal = OnlyStore->getOperand(0);
+ // If the replacement value is the load, this must occur in unreachable
+ // code.
+ if (ReplVal == LI)
+ ReplVal = UndefValue::get(LI->getType());
+ LI->replaceAllUsesWith(ReplVal);
if (AST && isa<PointerType>(LI->getType()))
AST->deleteValue(LI);
LI->eraseFromParent();
}
}
+namespace {
/// StoreIndexSearchPredicate - This is a helper predicate used to search by the
/// first element of a pair.
}
};
+}
+
/// PromoteSingleBlockAlloca - Many allocas are only used within a single basic
/// block. If this is the case, avoid traversing the CFG and inserting a lot of
/// potentially useless PHI nodes by just performing a single linear pass over
}
}
+// Inserts a llvm.dbg.value instrinsic before the stores to an alloca'd value
+// that has an associated llvm.dbg.decl intrinsic.
+void PromoteMem2Reg::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+ StoreInst *SI,
+ uint64_t Offset) {
+ if (!DDI)
+ return;
+
+ DIVariable DIVar(DDI->getVariable());
+ if (!DIVar.getNode())
+ return;
+
+ if (!DIF)
+ DIF = new DIFactory(*SI->getParent()->getParent()->getParent());
+ DIF->InsertDbgValueIntrinsic(SI->getOperand(0), Offset, DIVar, SI);
+}
// QueuePhiNode - queues a phi-node to be added to a basic-block for a specific
// Alloca returns true if there wasn't already a phi-node for that variable
// Create a PhiNode using the dereferenced type... and add the phi-node to the
// BasicBlock.
PN = PHINode::Create(Allocas[AllocaNo]->getAllocatedType(),
- Allocas[AllocaNo]->getName() + "." +
- utostr(Version++), BB->begin());
+ Allocas[AllocaNo]->getName() + "." + Twine(Version++),
+ BB->begin());
++NumPHIInsert;
PhiToAllocaMap[PN] = AllocaNo;
PN->reserveOperandSpace(getNumPreds(BB));
// what value were we writing?
IncomingVals[ai->second] = SI->getOperand(0);
+ // Record debuginfo for the store before removing it.
+ ConvertDebugDeclareToDebugValue(AllocaDbgDeclares[ai->second], SI, 0);
BB->getInstList().erase(SI);
}
}
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