[llvm] 2db9244 - [RemoveDIs][DebugInfo] Make DIAssignID always replaceable (#78300)

[via llvm-commits]

Author: Stephen Tozer
Date: 2024-01-17T12:00:30Z
New Revision: 2db9244b6f66a4fd4c937de7b33a5b6dda4a06a8

URL: https://github.com/llvm/llvm-project/commit/2db9244b6f66a4fd4c937de7b33a5b6dda4a06a8
DIFF: https://github.com/llvm/llvm-project/commit/2db9244b6f66a4fd4c937de7b33a5b6dda4a06a8.diff

LOG: [RemoveDIs][DebugInfo] Make DIAssignID always replaceable (#78300)

This patch is a necessary step to allowing the new non-intrinsic debug
info to replace llvm.dbg.assign intrinsics. DIAssignIDs must be able to
look up the debug assigns that refer to them, and this patch makes them
always be considered "replaceable", allowing us to track and replace uses
for non-temporary instances.

Added: 
    

Modified: 
    llvm/include/llvm/IR/DebugInfoMetadata.h
    llvm/include/llvm/IR/Metadata.h
    llvm/lib/IR/DebugInfo.cpp
    llvm/lib/IR/Metadata.cpp
    llvm/lib/IR/Verifier.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index f521862b1a54c2..156f6eb49253de 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -323,6 +323,10 @@ class DIAssignID : public MDNode {
   // This node has no operands to replace.
   void replaceOperandWith(unsigned I, Metadata *New) = delete;
 
+  SmallVector<DPValue *> getAllDPValueUsers() {
+    return Context.getReplaceableUses()->getAllDPValueUsers();
+  }
+
   static DIAssignID *getDistinct(LLVMContext &Context) {
     return getImpl(Context, Distinct);
   }

diff  --git a/llvm/include/llvm/IR/Metadata.h b/llvm/include/llvm/IR/Metadata.h
index b512451d385f63..befb6975ca18d4 100644
--- a/llvm/include/llvm/IR/Metadata.h
+++ b/llvm/include/llvm/IR/Metadata.h
@@ -1057,6 +1057,7 @@ struct TempMDNodeDeleter {
 class MDNode : public Metadata {
   friend class ReplaceableMetadataImpl;
   friend class LLVMContextImpl;
+  friend class DIAssignID;
 
   /// The header that is coallocated with an MDNode along with its "small"
   /// operands. It is located immediately before the main body of the node.
@@ -1239,7 +1240,8 @@ class MDNode : public Metadata {
   bool isDistinct() const { return Storage == Distinct; }
   bool isTemporary() const { return Storage == Temporary; }
 
-  bool isReplaceable() const { return isTemporary(); }
+  bool isReplaceable() const { return isTemporary() || isAlwaysReplaceable(); }
+  bool isAlwaysReplaceable() const { return getMetadataID() == DIAssignIDKind; }
 
   /// RAUW a temporary.
   ///

diff  --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index b9ab6f8ffda7a7..312d670d5b30e7 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -1787,13 +1787,6 @@ void at::deleteAssignmentMarkers(const Instruction *Inst) {
 }
 
 void at::RAUW(DIAssignID *Old, DIAssignID *New) {
-  // Replace MetadataAsValue uses.
-  if (auto *OldIDAsValue =
-          MetadataAsValue::getIfExists(Old->getContext(), Old)) {
-    auto *NewIDAsValue = MetadataAsValue::get(Old->getContext(), New);
-    OldIDAsValue->replaceAllUsesWith(NewIDAsValue);
-  }
-
   // Replace attachments.
   AssignmentInstRange InstRange = getAssignmentInsts(Old);
   // Use intermediate storage for the instruction ptrs because the
@@ -1802,6 +1795,8 @@ void at::RAUW(DIAssignID *Old, DIAssignID *New) {
   SmallVector<Instruction *> InstVec(InstRange.begin(), InstRange.end());
   for (auto *I : InstVec)
     I->setMetadata(LLVMContext::MD_DIAssignID, New);
+
+  Old->replaceAllUsesWith(New);
 }
 
 void at::deleteAll(Function *F) {

diff  --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index c8f01da30b99ae..a9f64f5442341c 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -439,16 +439,22 @@ void ReplaceableMetadataImpl::resolveAllUses(bool ResolveUsers) {
 // commentry in DIArgList::handleChangedOperand for details. Hidden behind
 // conditional compilation to avoid a compile time regression.
 ReplaceableMetadataImpl *ReplaceableMetadataImpl::getOrCreate(Metadata &MD) {
-  if (auto *N = dyn_cast<MDNode>(&MD))
-    return N->isResolved() ? nullptr : N->Context.getOrCreateReplaceableUses();
+  if (auto *N = dyn_cast<MDNode>(&MD)) {
+    return !N->isResolved() || N->isAlwaysReplaceable()
+               ? N->Context.getOrCreateReplaceableUses()
+               : nullptr;
+  }
   if (auto ArgList = dyn_cast<DIArgList>(&MD))
     return ArgList;
   return dyn_cast<ValueAsMetadata>(&MD);
 }
 
 ReplaceableMetadataImpl *ReplaceableMetadataImpl::getIfExists(Metadata &MD) {
-  if (auto *N = dyn_cast<MDNode>(&MD))
-    return N->isResolved() ? nullptr : N->Context.getReplaceableUses();
+  if (auto *N = dyn_cast<MDNode>(&MD)) {
+    return !N->isResolved() || N->isAlwaysReplaceable()
+               ? N->Context.getReplaceableUses()
+               : nullptr;
+  }
   if (auto ArgList = dyn_cast<DIArgList>(&MD))
     return ArgList;
   return dyn_cast<ValueAsMetadata>(&MD);
@@ -456,7 +462,7 @@ ReplaceableMetadataImpl *ReplaceableMetadataImpl::getIfExists(Metadata &MD) {
 
 bool ReplaceableMetadataImpl::isReplaceable(const Metadata &MD) {
   if (auto *N = dyn_cast<MDNode>(&MD))
-    return !N->isResolved();
+    return !N->isResolved() || N->isAlwaysReplaceable();
   return isa<ValueAsMetadata>(&MD) || isa<DIArgList>(&MD);
 }
 

diff  --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 7ee658c71d3df0..91cf91fbc788bd 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -173,6 +173,11 @@ struct VerifierSupport {
     }
   }
 
+  void Write(const DPValue *V) {
+    if (V)
+      V->print(*OS, MST, false);
+  }
+
   void Write(const Metadata *MD) {
     if (!MD)
       return;
@@ -4740,6 +4745,12 @@ void Verifier::visitDIAssignIDMetadata(Instruction &I, MDNode *MD) {
                 "dbg.assign not in same function as inst", DAI, &I);
     }
   }
+  for (DPValue *DPV : cast<DIAssignID>(MD)->getAllDPValueUsers()) {
+    CheckDI(DPV->isDbgAssign(),
+            "!DIAssignID should only be used by Assign DPVs.", MD, DPV);
+    CheckDI(DPV->getFunction() == I.getFunction(),
+            "DPVAssign not in same function as inst", DPV, &I);
+  }
 }
 
 void Verifier::visitCallStackMetadata(MDNode *MD) {