[llvm] [RemoveDIs][DebugInfo] Update SROA to handle DPVAssigns (PR #78475)
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Wed Jan 17 09:01:12 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
@llvm/pr-subscribers-debuginfo
Author: Stephen Tozer (SLTozer)
<details>
<summary>Changes</summary>
SROA needs to update llvm.dbg.assign intrinsics when it migrates debug info in response to alloca splitting; this patch updates the debug info migration code to handle DPVAssigns as well, making use of generic code to avoid duplication as much as possible.
---
Full diff: https://github.com/llvm/llvm-project/pull/78475.diff
2 Files Affected:
- (modified) llvm/include/llvm/IR/DebugInfo.h (+6)
- (modified) llvm/lib/Transforms/Scalar/SROA.cpp (+67-20)
``````````diff
diff --git a/llvm/include/llvm/IR/DebugInfo.h b/llvm/include/llvm/IR/DebugInfo.h
index e634f4bd2f5aaec..626f5d4b3191352 100644
--- a/llvm/include/llvm/IR/DebugInfo.h
+++ b/llvm/include/llvm/IR/DebugInfo.h
@@ -224,6 +224,12 @@ inline AssignmentMarkerRange getAssignmentMarkers(const Instruction *Inst) {
return make_range(Value::user_iterator(), Value::user_iterator());
}
+inline SmallVector<DPValue *> getDPVAssignmentMarkers(const Instruction *Inst) {
+ if (auto *ID = Inst->getMetadata(LLVMContext::MD_DIAssignID))
+ return cast<DIAssignID>(ID)->getAllDPValueUsers();
+ return {};
+}
+
/// Delete the llvm.dbg.assign intrinsics linked to \p Inst.
void deleteAssignmentMarkers(const Instruction *Inst);
diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index adf87ebb69f546b..79a75afbb6878b9 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -319,6 +319,29 @@ static DebugVariable getAggregateVariable(DbgVariableIntrinsic *DVI) {
return DebugVariable(DVI->getVariable(), std::nullopt,
DVI->getDebugLoc().getInlinedAt());
}
+static DebugVariable getAggregateVariable(DPValue *DPV) {
+ return DebugVariable(DPV->getVariable(), std::nullopt,
+ DPV->getDebugLoc().getInlinedAt());
+}
+
+static DPValue *createLinkedAssign(DPValue *, DIBuilder &DIB,
+ Instruction *LinkedInstr, Value *NewValue,
+ DILocalVariable *Variable,
+ DIExpression *Expression, Value *Address,
+ DIExpression *AddressExpression,
+ const DILocation *DI) {
+ (void)DIB;
+ return DPValue::createLinkedDPVAssign(LinkedInstr, NewValue, Variable,
+ Expression, Address, AddressExpression,
+ DI);
+}
+static DbgAssignIntrinsic *createLinkedAssign(
+ DbgAssignIntrinsic *, DIBuilder &DIB, Instruction *LinkedInstr,
+ Value *NewValue, DILocalVariable *Variable, DIExpression *Expression,
+ Value *Address, DIExpression *AddressExpression, const DILocation *DI) {
+ return DIB.insertDbgAssign(LinkedInstr, NewValue, Variable, Expression,
+ Address, AddressExpression, DI);
+}
/// Find linked dbg.assign and generate a new one with the correct
/// FragmentInfo. Link Inst to the new dbg.assign. If Value is nullptr the
@@ -340,8 +363,9 @@ static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
Instruction *Inst, Value *Dest, Value *Value,
const DataLayout &DL) {
auto MarkerRange = at::getAssignmentMarkers(OldInst);
+ auto DPVAssignMarkerRange = at::getDPVAssignmentMarkers(OldInst);
// Nothing to do if OldInst has no linked dbg.assign intrinsics.
- if (MarkerRange.empty())
+ if (MarkerRange.empty() && DPVAssignMarkerRange.empty())
return;
LLVM_DEBUG(dbgs() << " migrateDebugInfo\n");
@@ -362,6 +386,9 @@ static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
for (auto *DAI : at::getAssignmentMarkers(OldAlloca))
BaseFragments[getAggregateVariable(DAI)] =
DAI->getExpression()->getFragmentInfo();
+ for (auto *DPV : at::getDPVAssignmentMarkers(OldAlloca))
+ BaseFragments[getAggregateVariable(DPV)] =
+ DPV->getExpression()->getFragmentInfo();
// The new inst needs a DIAssignID unique metadata tag (if OldInst has
// one). It shouldn't already have one: assert this assumption.
@@ -371,7 +398,7 @@ static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
DIBuilder DIB(*OldInst->getModule(), /*AllowUnresolved*/ false);
assert(OldAlloca->isStaticAlloca());
- for (DbgAssignIntrinsic *DbgAssign : MarkerRange) {
+ auto MigrateDbgAssign = [&](auto DbgAssign) {
LLVM_DEBUG(dbgs() << " existing dbg.assign is: " << *DbgAssign
<< "\n");
auto *Expr = DbgAssign->getExpression();
@@ -382,7 +409,7 @@ static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
{
auto R = BaseFragments.find(getAggregateVariable(DbgAssign));
if (R == BaseFragments.end())
- continue;
+ return;
BaseFragment = R->second;
}
std::optional<DIExpression::FragmentInfo> CurrentFragment =
@@ -393,7 +420,7 @@ static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
BaseFragment, CurrentFragment, NewFragment);
if (Result == Skip)
- continue;
+ return;
if (Result == UseFrag && !(NewFragment == CurrentFragment)) {
if (CurrentFragment) {
// Rewrite NewFragment to be relative to the existing one (this is
@@ -425,9 +452,10 @@ static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
}
::Value *NewValue = Value ? Value : DbgAssign->getValue();
- auto *NewAssign = DIB.insertDbgAssign(
- Inst, NewValue, DbgAssign->getVariable(), Expr, Dest,
- DIExpression::get(Ctx, std::nullopt), DbgAssign->getDebugLoc());
+ auto *NewAssign = createLinkedAssign(
+ DbgAssign, DIB, Inst, NewValue, DbgAssign->getVariable(), Expr, Dest,
+ DIExpression::get(Expr->getContext(), std::nullopt),
+ DbgAssign->getDebugLoc());
// If we've updated the value but the original dbg.assign has an arglist
// then kill it now - we can't use the requested new value.
@@ -461,9 +489,11 @@ static void migrateDebugInfo(AllocaInst *OldAlloca, bool IsSplit,
NewAssign->moveBefore(DbgAssign);
NewAssign->setDebugLoc(DbgAssign->getDebugLoc());
- LLVM_DEBUG(dbgs() << "Created new assign intrinsic: " << *NewAssign
- << "\n");
- }
+ LLVM_DEBUG(dbgs() << "Created new assign: " << *NewAssign << "\n");
+ };
+
+ for_each(MarkerRange, MigrateDbgAssign);
+ for_each(DPVAssignMarkerRange, MigrateDbgAssign);
}
namespace {
@@ -3108,6 +3138,7 @@ class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
// emit dbg.assign intrinsics for mem intrinsics storing through non-
// constant geps, or storing a variable number of bytes.
assert(at::getAssignmentMarkers(&II).empty() &&
+ at::getDPVAssignmentMarkers(&II).empty() &&
"AT: Unexpected link to non-const GEP");
deleteIfTriviallyDead(OldPtr);
return false;
@@ -3254,11 +3285,13 @@ class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
Value *AdjustedPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
if (IsDest) {
// Update the address component of linked dbg.assigns.
- for (auto *DAI : at::getAssignmentMarkers(&II)) {
- if (llvm::is_contained(DAI->location_ops(), II.getDest()) ||
- DAI->getAddress() == II.getDest())
- DAI->replaceVariableLocationOp(II.getDest(), AdjustedPtr);
- }
+ auto UpdateAssignAddress = [&](auto *DbgAssign) {
+ if (llvm::is_contained(DbgAssign->location_ops(), II.getDest()) ||
+ DbgAssign->getAddress() == II.getDest())
+ DbgAssign->replaceVariableLocationOp(II.getDest(), AdjustedPtr);
+ };
+ for_each(at::getAssignmentMarkers(&II), UpdateAssignAddress);
+ for_each(at::getDPVAssignmentMarkers(&II), UpdateAssignAddress);
II.setDest(AdjustedPtr);
II.setDestAlignment(SliceAlign);
} else {
@@ -3842,6 +3875,7 @@ class AggLoadStoreRewriter : public InstVisitor<AggLoadStoreRewriter, bool> {
DL);
} else {
assert(at::getAssignmentMarkers(Store).empty() &&
+ at::getDPVAssignmentMarkers(Store).empty() &&
"AT: unexpected debug.assign linked to store through "
"unbounded GEP");
}
@@ -4861,10 +4895,21 @@ static void insertNewDbgInst(DIBuilder &DIB, DPValue *Orig, AllocaInst *NewAddr,
DIExpression *NewFragmentExpr,
Instruction *BeforeInst) {
(void)DIB;
- DPValue *New = new DPValue(ValueAsMetadata::get(NewAddr), Orig->getVariable(),
- NewFragmentExpr, Orig->getDebugLoc(),
- DPValue::LocationType::Declare);
- BeforeInst->getParent()->insertDPValueBefore(New, BeforeInst->getIterator());
+ if (Orig->isDbgDeclare()) {
+ DPValue *DPV = DPValue::createDPVDeclare(NewAddr, Orig->getVariable(), NewFragmentExpr,
+ Orig->getDebugLoc());
+ BeforeInst->getParent()->insertDPValueBefore(DPV, BeforeInst->getIterator());
+ return;
+ }
+ if (!NewAddr->hasMetadata(LLVMContext::MD_DIAssignID)) {
+ NewAddr->setMetadata(LLVMContext::MD_DIAssignID,
+ DIAssignID::getDistinct(NewAddr->getContext()));
+ }
+ auto *NewAssign = DPValue::createLinkedDPVAssign(
+ NewAddr, Orig->getValue(), Orig->getVariable(), NewFragmentExpr, NewAddr,
+ Orig->getAddressExpression(), Orig->getDebugLoc());
+ LLVM_DEBUG(dbgs() << "Created new DPVAssign: " << *NewAssign << "\n");
+ (void)NewAssign;
}
/// Walks the slices of an alloca and form partitions based on them,
@@ -5042,6 +5087,7 @@ bool SROA::splitAlloca(AllocaInst &AI, AllocaSlices &AS) {
for_each(findDbgDeclares(&AI), MigrateOne);
for_each(findDPVDeclares(&AI), MigrateOne);
for_each(at::getAssignmentMarkers(&AI), MigrateOne);
+ for_each(at::getDPVAssignmentMarkers(&AI), MigrateOne);
return Changed;
}
@@ -5262,8 +5308,9 @@ std::pair<bool /*Changed*/, bool /*CFGChanged*/> SROA::runSROA(Function &F) {
"Should not have modified the CFG when told to preserve it.");
if (Changed && isAssignmentTrackingEnabled(*F.getParent())) {
- for (auto &BB : F)
+ for (auto &BB : F) {
RemoveRedundantDbgInstrs(&BB);
+ }
}
return {Changed, CFGChanged};
``````````
</details>
https://github.com/llvm/llvm-project/pull/78475
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