Merge pull request #71810 from eeckstein/remove-inst-leak-checking

SIL: remove instruction leaks checking

Author: eeckstein

include/swift/AST/SILOptions.h

@@ -270,12 +270,6 @@ class SILOptions {
   /// Are we parsing the stdlib, i.e. -parse-stdlib?
   bool ParseStdlib = false;
 
-  /// If true, check for leaking instructions when the SILModule is destructed.
-  ///
-  /// Warning: this is not thread safe. It can only be enabled in case there
-  /// is a single SILModule in a single thread.
-  bool checkSILModuleLeaks = false;
-
   /// Are we building in embedded Swift mode?
   bool EmbeddedSwift = false;
 

include/swift/SIL/SILInstruction.h

@@ -900,11 +900,6 @@ class SILInstruction : public llvm::ilist_node<SILInstruction> {
     return NumDeletedInstructions;
   }
 
-  static void resetInstructionCounts() {
-    NumCreatedInstructions = 0;
-    NumDeletedInstructions = 0;
-  }
-
   /// Pretty-print the value.
   void dump() const;
   void print(raw_ostream &OS) const;

include/swift/SIL/SILModule.h

@@ -939,19 +939,6 @@ class SILModule {
   /// Check linear OSSA lifetimes, assuming complete OSSA.
   void verifyOwnership() const;
 
-  /// Check if there are any leaking instructions.
-  ///
-  /// Aborts with an error if more instructions are allocated than contained in
-  /// the module.
-  void checkForLeaks() const;
-
-  /// Check if there are any leaking instructions after the SILModule is
-  /// destructed.
-  ///
-  /// The SILModule destructor already calls checkForLeaks(). This function is
-  /// useful to check if the destructor itself destroys all data structures.
-  static void checkForLeaksAfterDestruction();
-
   /// Pretty-print the module.
   void dump(bool Verbose = false) const;
 

lib/DriverTool/sil_opt_main.cpp

@@ -708,7 +708,6 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   SILOpts.VerifySILOwnership = !options.DisableSILOwnershipVerifier;
   SILOpts.OptRecordFile = options.RemarksFilename;
   SILOpts.OptRecordPasses = options.RemarksPasses;
-  SILOpts.checkSILModuleLeaks = true;
   SILOpts.EnableStackProtection = true;
   SILOpts.EnableMoveInoutStackProtection = options.EnableMoveInoutStackProtection;
 

lib/FrontendTool/FrontendTool.cpp

@@ -2235,10 +2235,6 @@ int swift::performFrontend(ArrayRef<const char *> Args,
     llvm::setBugReportMsg(nullptr);
   }
 
-  /// Enable leaks checking because this SILModule is the only one in the process
-  /// (leaks checking is not thread safe).
-  Invocation.getSILOptions().checkSILModuleLeaks = true;
-
   PrettyStackTraceFrontend frontendTrace(Invocation);
 
   // Make an array of PrettyStackTrace objects to dump the configuration files

lib/IRGen/IRGen.cpp

@@ -1231,10 +1231,7 @@ GeneratedModule IRGenRequest::evaluate(Evaluator &evaluator,
   // Free the memory occupied by the SILModule.
   // Execute this task in parallel to the embedding of bitcode.
   auto SILModuleRelease = [&SILMod]() {
-    bool checkForLeaks = SILMod->getOptions().checkSILModuleLeaks;
     SILMod.reset(nullptr);
-    if (checkForLeaks)
-      SILModule::checkForLeaksAfterDestruction();
   };
   auto Thread = std::thread(SILModuleRelease);
   // Wait for the thread to terminate.
@@ -1546,10 +1543,7 @@ static void performParallelIRGeneration(IRGenDescriptor desc) {
   // Free the memory occupied by the SILModule.
   // Execute this task in parallel to the LLVM compilation.
   auto SILModuleRelease = [&SILMod]() {
-    bool checkForLeaks = SILMod->getOptions().checkSILModuleLeaks;
     SILMod.reset(nullptr);
-    if (checkForLeaks)
-      SILModule::checkForLeaksAfterDestruction();
   };
   auto releaseModuleThread = std::thread(SILModuleRelease);
 

lib/SIL/IR/SILModule.cpp

@@ -126,8 +126,6 @@ SILModule::SILModule(llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
 
 SILModule::~SILModule() {
 #ifndef NDEBUG
-  checkForLeaks();
-
   NumSlabsAllocated += numAllocatedSlabs;
   assert(numAllocatedSlabs == freeSlabs.size() && "leaking slabs in SILModule");
 #endif
@@ -163,65 +161,6 @@ SILModule::~SILModule() {
   flushDeletedInsts();
 }
 
-void SILModule::checkForLeaks() const {
-
-  /// Leak checking is not thread safe, because the instruction counters are
-  /// global non-atomic variables. Leak checking can only be done in case there
-  /// is a single SILModule in a single thread.
-  if (!getOptions().checkSILModuleLeaks)
-    return;
-
-  int instsInModule = scheduledForDeletion.size();
-
-  for (const SILFunction &F : *this) {
-    const SILFunction *sn = &F;
-    do {
-      for (const SILBasicBlock &block : *sn) {
-        instsInModule += std::distance(block.begin(), block.end());
-      }
-    } while ((sn = sn->snapshots) != nullptr);
-  }
-  for (const SILFunction &F : zombieFunctions) {
-    const SILFunction *sn = &F;
-    do {
-      for (const SILBasicBlock &block : F) {
-        instsInModule += std::distance(block.begin(), block.end());
-      }
-    } while ((sn = sn->snapshots) != nullptr);
-  }
-  for (const SILGlobalVariable &global : getSILGlobals()) {
-      instsInModule += std::distance(global.StaticInitializerBlock.begin(),
-                                     global.StaticInitializerBlock.end());
-  }
-  
-  int numAllocated = SILInstruction::getNumCreatedInstructions() -
-                       SILInstruction::getNumDeletedInstructions();
-                       
-  if (numAllocated != instsInModule) {
-    llvm::errs() << "Leaking instructions!\n";
-    llvm::errs() << "Allocated instructions: " << numAllocated << '\n';
-    llvm::errs() << "Instructions in module: " << instsInModule << '\n';
-    llvm_unreachable("leaking instructions");
-  }
-  
-  assert(PlaceholderValue::getNumPlaceholderValuesAlive() == 0 &&
-         "leaking placeholders");
-}
-
-void SILModule::checkForLeaksAfterDestruction() {
-// Disabled in release (non-assert) builds because this check fails in rare
-// cases in lldb, causing crashes. rdar://70826934
-#ifndef NDEBUG
-  int numAllocated = SILInstruction::getNumCreatedInstructions() -
-                     SILInstruction::getNumDeletedInstructions();
-
-  if (numAllocated != 0) {
-    llvm::errs() << "Leaking " << numAllocated << " instructions!\n";
-    llvm_unreachable("leaking instructions");
-  }
-#endif
-}
-
 std::unique_ptr<SILModule> SILModule::createEmptyModule(
     llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
     Lowering::TypeConverter &TC, const SILOptions &Options,

lib/SIL/Parser/ParseSIL.cpp

@@ -101,9 +101,6 @@ ParseSILModuleRequest::evaluate(Evaluator &evaluator,
   auto bufferID = SF->getBufferID();
   assert(bufferID);
 
-  // For leak detection.
-  SILInstruction::resetInstructionCounts();
-
   auto silMod = SILModule::createEmptyModule(desc.context, desc.conv,
                                              desc.opts);
   SILParserState parserState(*silMod.get());

lib/SIL/Verifier/SILVerifier.cpp

@@ -7255,8 +7255,6 @@ void SILModule::verify(CalleeCache *calleeCache,
   if (!verificationEnabled(*this))
     return;
 
-  checkForLeaks();
-
   // Uniquing set to catch symbol name collisions.
   llvm::DenseSet<StringRef> symbolNames;
 

lib/SILGen/SILGen.cpp

@@ -2115,9 +2115,6 @@ ASTLoweringRequest::evaluate(Evaluator &evaluator,
     return evaluateOrFatal(evaluator, ParseSILModuleRequest{desc});
   }
 
-  // For leak detection.
-  SILInstruction::resetInstructionCounts();
-
   auto silMod = SILModule::createEmptyModule(desc.context, desc.conv,
                                              desc.opts, desc.irgenOptions);