ARCCodeMotion: support bisecting individual optimized retain-instructions when debugging this pass.

Author: eeckstein

lib/SILOptimizer/Transforms/ARCCodeMotion.cpp

@@ -140,6 +140,8 @@ struct BlockState {
 /// code motion procedure should be.
 class CodeMotionContext {
 protected:
+  SILFunctionTransform *parentTransform;
+
   /// Dataflow needs multiple iteration to converge. If this is false, then we
   /// do not need to generate the genset or killset, i.e. we can simply do 1
   /// pessimistic data flow iteration.
@@ -202,11 +204,13 @@ class CodeMotionContext {
 
 public:
   /// Constructor.
-  CodeMotionContext(llvm::SpecificBumpPtrAllocator<BlockState> &BPA,
+  CodeMotionContext(SILFunctionTransform *parentTransform,
+                    llvm::SpecificBumpPtrAllocator<BlockState> &BPA,
                     SILFunction *F,
                     PostOrderFunctionInfo *PO, AliasAnalysis *AA,
                     RCIdentityFunctionInfo *RCFI)
-    : MultiIteration(true), BPA(BPA), F(F), PO(PO), AA(AA), RCFI(RCFI),
+    : parentTransform(parentTransform),
+      MultiIteration(true), BPA(BPA), F(F), PO(PO), AA(AA), RCFI(RCFI),
       InterestBlocks(F) {}
 
   /// virtual destructor.
@@ -310,11 +314,16 @@ class RetainBlockState : public BlockState {
 
 /// RetainCodeMotionContext - Context to perform retain code motion.
 class RetainCodeMotionContext : public CodeMotionContext {
-  /// All the retain block state for all the basic blocks in the function. 
+  /// All the retain block state for all the basic blocks in the function.
   BasicBlockData<RetainBlockState> BlockStates;
 
+  InstructionSet retainInstructions;
+
   ProgramTerminationFunctionInfo PTFI;
 
+  bool isRetain(SILInstruction *inst) const {
+    return retainInstructions.contains(inst);
+  }
   /// Return true if the instruction blocks the Ptr to be moved further.
   bool mayBlockCodeMotion(SILInstruction *II, SILValue Ptr) override {
     // NOTE: If more checks are to be added, place the most expensive in the
@@ -326,7 +335,7 @@ class RetainCodeMotionContext : public CodeMotionContext {
       return true;
     // Identical RC root blocks code motion, we will be able to move this retain
     // further once we move the blocking retain.
-    if (isRetainInstruction(II) && getRCRoot(II) == Ptr) {
+    if (isRetain(II) && getRCRoot(II) == Ptr) {
       LLVM_DEBUG(if (printCtx) llvm::dbgs()
                  << "Retain " << Ptr << "  at matching retain " << *II);
       return true;
@@ -353,17 +362,19 @@ class RetainCodeMotionContext : public CodeMotionContext {
     if (&*I->getParent()->begin() == I)
       return nullptr;
     auto Prev = &*std::prev(SILBasicBlock::iterator(I));
-    if (isRetainInstruction(Prev) && getRCRoot(Prev) == Root)
+    if (isRetain(Prev) && getRCRoot(Prev) == Root)
       return Prev;
     return nullptr;
   }
 
 public:
   /// Constructor.
-  RetainCodeMotionContext(llvm::SpecificBumpPtrAllocator<BlockState> &BPA,
+  RetainCodeMotionContext(SILFunctionTransform *parentTransform,
+                          llvm::SpecificBumpPtrAllocator<BlockState> &BPA,
                           SILFunction *F, PostOrderFunctionInfo *PO,
                           AliasAnalysis *AA, RCIdentityFunctionInfo *RCFI)
-      : CodeMotionContext(BPA, F, PO, AA, RCFI), BlockStates(F), PTFI(F) {}
+      : CodeMotionContext(parentTransform, BPA, F, PO, AA, RCFI),
+        BlockStates(F), retainInstructions(F), PTFI(F) {}
 
   /// virtual destructor.
   ~RetainCodeMotionContext() override {}
@@ -419,6 +430,9 @@ void RetainCodeMotionContext::initializeCodeMotionDataFlow() {
     for (auto &II : BB) {
       if (!isRetainInstruction(&II))
         continue;
+      if (!parentTransform->continueWithNextSubpassRun(&II))
+        continue;
+      retainInstructions.insert(&II);
       RCInstructions.insert(&II);
       SILValue Root = getRCRoot(&II);
       if (RCRootIndex.find(Root) != RCRootIndex.end())
@@ -457,7 +471,7 @@ void RetainCodeMotionContext::initializeCodeMotionBBMaxSet() {
    // NOTE: this is a conservative approximation, because some retains may be
    // blocked before it reaches this block.
    for (auto &II : *BB) {
-      if (!isRetainInstruction(&II))
+      if (!isRetain(&II))
         continue;
       State.BBMaxSet.set(RCRootIndex[getRCRoot(&II)]);
     }
@@ -479,7 +493,7 @@ void RetainCodeMotionContext::computeCodeMotionGenKillSet() {
         State.BBGenSet.reset(i);
       }
       // If this is a retain instruction, it also generates.
-      if (isRetainInstruction(&I)) {
+      if (isRetain(&I)) {
         unsigned idx = RCRootIndex[getRCRoot(&I)];
         State.BBGenSet.set(idx);
         assert(State.BBKillSet.test(idx) && "Killset computed incorrectly");
@@ -622,7 +636,7 @@ void RetainCodeMotionContext::computeCodeMotionInsertPoints() {
       }
 
       // If this is a retain instruction, it also generates.
-      if (isRetainInstruction(&*I)) {
+      if (isRetain(&*I)) {
         S.BBSetIn.set(RCRootIndex[getRCRoot(&*I)]);
       }
     }
@@ -668,8 +682,6 @@ class ReleaseBlockState : public BlockState {
 
 /// ReleaseCodeMotionContext - Context to perform release code motion.
 class ReleaseCodeMotionContext : public CodeMotionContext {
-  SILFunctionTransform *parentTransform;
-
   /// All the release block state for all the basic blocks in the function.
   BasicBlockData<ReleaseBlockState> BlockStates;
 
@@ -730,8 +742,7 @@ class ReleaseCodeMotionContext : public CodeMotionContext {
                            AliasAnalysis *AA, RCIdentityFunctionInfo *RCFI,
                            bool FreezeEpilogueReleases,
                            ConsumedArgToEpilogueReleaseMatcher &ERM)
-      : CodeMotionContext(BPA, F, PO, AA, RCFI),
-        parentTransform(parentTransform),
+      : CodeMotionContext(parentTransform, BPA, F, PO, AA, RCFI),
         BlockStates(F),
         releaseInstructions(F),
         FreezeEpilogueReleases(FreezeEpilogueReleases), ERM(ERM) {}
@@ -1232,7 +1243,7 @@ class ARCCodeMotion : public SILFunctionTransform {
       // Run release hoisting.
       InstChanged |= RelCM.run();
     } else {
-      RetainCodeMotionContext RetCM(BPA, F, PO, AA, RCFI);
+      RetainCodeMotionContext RetCM(this, BPA, F, PO, AA, RCFI);
       // Run retain sinking.
       InstChanged |= RetCM.run();
       // Eliminate any retains that are right before program termination