Export clang-format16 via ydblib project

6e6be3a95868fde888d801b7590af4044049563f

1 files changed, 2560 insertions, 0 deletions

diff --git a/contrib/libs/clang16/lib/Sema/AnalysisBasedWarnings.cpp b/contrib/libs/clang16/lib/Sema/AnalysisBasedWarnings.cpp
new file mode 100644
index 0000000000..4530154ac9
--- /dev/null
+++ b/contrib/libs/clang16/lib/Sema/AnalysisBasedWarnings.cpp
@@ -0,0 +1,2560 @@
+//=- AnalysisBasedWarnings.cpp - Sema warnings based on libAnalysis -*- C++ -*-=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines analysis_warnings::[Policy,Executor].
+// Together they are used by Sema to issue warnings based on inexpensive
+// static analysis algorithms in libAnalysis.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Sema/AnalysisBasedWarnings.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/EvaluatedExprVisitor.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ExprObjC.h"
+#include "clang/AST/OperationKinds.h"
+#include "clang/AST/ParentMap.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/AST/StmtObjC.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
+#include "clang/Analysis/Analyses/CalledOnceCheck.h"
+#include "clang/Analysis/Analyses/Consumed.h"
+#include "clang/Analysis/Analyses/ReachableCode.h"
+#include "clang/Analysis/Analyses/ThreadSafety.h"
+#include "clang/Analysis/Analyses/UninitializedValues.h"
+#include "clang/Analysis/Analyses/UnsafeBufferUsage.h"
+#include "clang/Analysis/AnalysisDeclContext.h"
+#include "clang/Analysis/CFG.h"
+#include "clang/Analysis/CFGStmtMap.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Sema/ScopeInfo.h"
+#include "clang/Sema/SemaInternal.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Casting.h"
+#include <algorithm>
+#include <deque>
+#include <iterator>
+#include <optional>
+
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// Unreachable code analysis.
+//===----------------------------------------------------------------------===//
+
+namespace {
+  class UnreachableCodeHandler : public reachable_code::Callback {
+    Sema &S;
+    SourceRange PreviousSilenceableCondVal;
+
+  public:
+    UnreachableCodeHandler(Sema &s) : S(s) {}
+
+    void HandleUnreachable(reachable_code::UnreachableKind UK,
+                           SourceLocation L,
+                           SourceRange SilenceableCondVal,
+                           SourceRange R1,
+                           SourceRange R2) override {
+      // Avoid reporting multiple unreachable code diagnostics that are
+      // triggered by the same conditional value.
+      if (PreviousSilenceableCondVal.isValid() &&
+          SilenceableCondVal.isValid() &&
+          PreviousSilenceableCondVal == SilenceableCondVal)
+        return;
+      PreviousSilenceableCondVal = SilenceableCondVal;
+
+      unsigned diag = diag::warn_unreachable;
+      switch (UK) {
+        case reachable_code::UK_Break:
+          diag = diag::warn_unreachable_break;
+          break;
+        case reachable_code::UK_Return:
+          diag = diag::warn_unreachable_return;
+          break;
+        case reachable_code::UK_Loop_Increment:
+          diag = diag::warn_unreachable_loop_increment;
+          break;
+        case reachable_code::UK_Other:
+          break;
+      }
+
+      S.Diag(L, diag) << R1 << R2;
+
+      SourceLocation Open = SilenceableCondVal.getBegin();
+      if (Open.isValid()) {
+        SourceLocation Close = SilenceableCondVal.getEnd();
+        Close = S.getLocForEndOfToken(Close);
+        if (Close.isValid()) {
+          S.Diag(Open, diag::note_unreachable_silence)
+            << FixItHint::CreateInsertion(Open, "/* DISABLES CODE */ (")
+            << FixItHint::CreateInsertion(Close, ")");
+        }
+      }
+    }
+  };
+} // anonymous namespace
+
+/// CheckUnreachable - Check for unreachable code.
+static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC) {
+  // As a heuristic prune all diagnostics not in the main file.  Currently
+  // the majority of warnings in headers are false positives.  These
+  // are largely caused by configuration state, e.g. preprocessor
+  // defined code, etc.
+  //
+  // Note that this is also a performance optimization.  Analyzing
+  // headers many times can be expensive.
+  if (!S.getSourceManager().isInMainFile(AC.getDecl()->getBeginLoc()))
+    return;
+
+  UnreachableCodeHandler UC(S);
+  reachable_code::FindUnreachableCode(AC, S.getPreprocessor(), UC);
+}
+
+namespace {
+/// Warn on logical operator errors in CFGBuilder
+class LogicalErrorHandler : public CFGCallback {
+  Sema &S;
+
+public:
+  LogicalErrorHandler(Sema &S) : S(S) {}
+
+  static bool HasMacroID(const Expr *E) {
+    if (E->getExprLoc().isMacroID())
+      return true;
+
+    // Recurse to children.
+    for (const Stmt *SubStmt : E->children())
+      if (const Expr *SubExpr = dyn_cast_or_null<Expr>(SubStmt))
+        if (HasMacroID(SubExpr))
+          return true;
+
+    return false;
+  }
+
+  void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue) override {
+    if (HasMacroID(B))
+      return;
+
+    SourceRange DiagRange = B->getSourceRange();
+    S.Diag(B->getExprLoc(), diag::warn_tautological_overlap_comparison)
+        << DiagRange << isAlwaysTrue;
+  }
+
+  void compareBitwiseEquality(const BinaryOperator *B,
+                              bool isAlwaysTrue) override {
+    if (HasMacroID(B))
+      return;
+
+    SourceRange DiagRange = B->getSourceRange();
+    S.Diag(B->getExprLoc(), diag::warn_comparison_bitwise_always)
+        << DiagRange << isAlwaysTrue;
+  }
+
+  void compareBitwiseOr(const BinaryOperator *B) override {
+    if (HasMacroID(B))
+      return;
+
+    SourceRange DiagRange = B->getSourceRange();
+    S.Diag(B->getExprLoc(), diag::warn_comparison_bitwise_or) << DiagRange;
+  }
+
+  static bool hasActiveDiagnostics(DiagnosticsEngine &Diags,
+                                   SourceLocation Loc) {
+    return !Diags.isIgnored(diag::warn_tautological_overlap_comparison, Loc) ||
+           !Diags.isIgnored(diag::warn_comparison_bitwise_or, Loc);
+  }
+};
+} // anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// Check for infinite self-recursion in functions
+//===----------------------------------------------------------------------===//
+
+// Returns true if the function is called anywhere within the CFGBlock.
+// For member functions, the additional condition of being call from the
+// this pointer is required.
+static bool hasRecursiveCallInPath(const FunctionDecl *FD, CFGBlock &Block) {
+  // Process all the Stmt's in this block to find any calls to FD.
+  for (const auto &B : Block) {
+    if (B.getKind() != CFGElement::Statement)
+      continue;
+
+    const CallExpr *CE = dyn_cast<CallExpr>(B.getAs<CFGStmt>()->getStmt());
+    if (!CE || !CE->getCalleeDecl() ||
+        CE->getCalleeDecl()->getCanonicalDecl() != FD)
+      continue;
+
+    // Skip function calls which are qualified with a templated class.
+    if (const DeclRefExpr *DRE =
+            dyn_cast<DeclRefExpr>(CE->getCallee()->IgnoreParenImpCasts())) {
+      if (NestedNameSpecifier *NNS = DRE->getQualifier()) {
+        if (NNS->getKind() == NestedNameSpecifier::TypeSpec &&
+            isa<TemplateSpecializationType>(NNS->getAsType())) {
+          continue;
+        }
+      }
+    }
+
+    const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(CE);
+    if (!MCE || isa<CXXThisExpr>(MCE->getImplicitObjectArgument()) ||
+        !MCE->getMethodDecl()->isVirtual())
+      return true;
+  }
+  return false;
+}
+
+// Returns true if every path from the entry block passes through a call to FD.
+static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg) {
+  llvm::SmallPtrSet<CFGBlock *, 16> Visited;
+  llvm::SmallVector<CFGBlock *, 16> WorkList;
+  // Keep track of whether we found at least one recursive path.
+  bool foundRecursion = false;
+
+  const unsigned ExitID = cfg->getExit().getBlockID();
+
+  // Seed the work list with the entry block.
+  WorkList.push_back(&cfg->getEntry());
+
+  while (!WorkList.empty()) {
+    CFGBlock *Block = WorkList.pop_back_val();
+
+    for (auto I = Block->succ_begin(), E = Block->succ_end(); I != E; ++I) {
+      if (CFGBlock *SuccBlock = *I) {
+        if (!Visited.insert(SuccBlock).second)
+          continue;
+
+        // Found a path to the exit node without a recursive call.
+        if (ExitID == SuccBlock->getBlockID())
+          return false;
+
+        // If the successor block contains a recursive call, end analysis there.
+        if (hasRecursiveCallInPath(FD, *SuccBlock)) {
+          foundRecursion = true;
+          continue;
+        }
+
+        WorkList.push_back(SuccBlock);
+      }
+    }
+  }
+  return foundRecursion;
+}
+
+static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,
+                                   const Stmt *Body, AnalysisDeclContext &AC) {
+  FD = FD->getCanonicalDecl();
+
+  // Only run on non-templated functions and non-templated members of
+  // templated classes.
+  if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate &&
+      FD->getTemplatedKind() != FunctionDecl::TK_MemberSpecialization)
+    return;
+
+  CFG *cfg = AC.getCFG();
+  if (!cfg) return;
+
+  // If the exit block is unreachable, skip processing the function.
+  if (cfg->getExit().pred_empty())
+    return;
+
+  // Emit diagnostic if a recursive function call is detected for all paths.
+  if (checkForRecursiveFunctionCall(FD, cfg))
+    S.Diag(Body->getBeginLoc(), diag::warn_infinite_recursive_function);
+}
+
+//===----------------------------------------------------------------------===//
+// Check for throw in a non-throwing function.
+//===----------------------------------------------------------------------===//
+
+/// Determine whether an exception thrown by E, unwinding from ThrowBlock,
+/// can reach ExitBlock.
+static bool throwEscapes(Sema &S, const CXXThrowExpr *E, CFGBlock &ThrowBlock,
+                         CFG *Body) {
+  SmallVector<CFGBlock *, 16> Stack;
+  llvm::BitVector Queued(Body->getNumBlockIDs());
+
+  Stack.push_back(&ThrowBlock);
+  Queued[ThrowBlock.getBlockID()] = true;
+
+  while (!Stack.empty()) {
+    CFGBlock &UnwindBlock = *Stack.back();
+    Stack.pop_back();
+
+    for (auto &Succ : UnwindBlock.succs()) {
+      if (!Succ.isReachable() || Queued[Succ->getBlockID()])
+        continue;
+
+      if (Succ->getBlockID() == Body->getExit().getBlockID())
+        return true;
+
+      if (auto *Catch =
+              dyn_cast_or_null<CXXCatchStmt>(Succ->getLabel())) {
+        QualType Caught = Catch->getCaughtType();
+        if (Caught.isNull() || // catch (...) catches everything
+            !E->getSubExpr() || // throw; is considered cuaght by any handler
+            S.handlerCanCatch(Caught, E->getSubExpr()->getType()))
+          // Exception doesn't escape via this path.
+          break;
+      } else {
+        Stack.push_back(Succ);
+        Queued[Succ->getBlockID()] = true;
+      }
+    }
+  }
+
+  return false;
+}
+
+static void visitReachableThrows(
+    CFG *BodyCFG,
+    llvm::function_ref<void(const CXXThrowExpr *, CFGBlock &)> Visit) {
+  llvm::BitVector Reachable(BodyCFG->getNumBlockIDs());
+  clang::reachable_code::ScanReachableFromBlock(&BodyCFG->getEntry(), Reachable);
+  for (CFGBlock *B : *BodyCFG) {
+    if (!Reachable[B->getBlockID()])
+      continue;
+    for (CFGElement &E : *B) {
+      std::optional<CFGStmt> S = E.getAs<CFGStmt>();
+      if (!S)
+        continue;
+      if (auto *Throw = dyn_cast<CXXThrowExpr>(S->getStmt()))
+        Visit(Throw, *B);
+    }
+  }
+}
+
+static void EmitDiagForCXXThrowInNonThrowingFunc(Sema &S, SourceLocation OpLoc,
+                                                 const FunctionDecl *FD) {
+  if (!S.getSourceManager().isInSystemHeader(OpLoc) &&
+      FD->getTypeSourceInfo()) {
+    S.Diag(OpLoc, diag::warn_throw_in_noexcept_func) << FD;
+    if (S.getLangOpts().CPlusPlus11 &&
+        (isa<CXXDestructorDecl>(FD) ||
+         FD->getDeclName().getCXXOverloadedOperator() == OO_Delete ||
+         FD->getDeclName().getCXXOverloadedOperator() == OO_Array_Delete)) {
+      if (const auto *Ty = FD->getTypeSourceInfo()->getType()->
+                                         getAs<FunctionProtoType>())
+        S.Diag(FD->getLocation(), diag::note_throw_in_dtor)
+            << !isa<CXXDestructorDecl>(FD) << !Ty->hasExceptionSpec()
+            << FD->getExceptionSpecSourceRange();
+    } else
+      S.Diag(FD->getLocation(), diag::note_throw_in_function)
+          << FD->getExceptionSpecSourceRange();
+  }
+}
+
+static void checkThrowInNonThrowingFunc(Sema &S, const FunctionDecl *FD,
+                                        AnalysisDeclContext &AC) {
+  CFG *BodyCFG = AC.getCFG();
+  if (!BodyCFG)
+    return;
+  if (BodyCFG->getExit().pred_empty())
+    return;
+  visitReachableThrows(BodyCFG, [&](const CXXThrowExpr *Throw, CFGBlock &Block) {
+    if (throwEscapes(S, Throw, Block, BodyCFG))
+      EmitDiagForCXXThrowInNonThrowingFunc(S, Throw->getThrowLoc(), FD);
+  });
+}
+
+static bool isNoexcept(const FunctionDecl *FD) {
+  const auto *FPT = FD->getType()->castAs<FunctionProtoType>();
+  if (FPT->isNothrow() || FD->hasAttr<NoThrowAttr>())
+    return true;
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Check for missing return value.
+//===----------------------------------------------------------------------===//
+
+enum ControlFlowKind {
+  UnknownFallThrough,
+  NeverFallThrough,
+  MaybeFallThrough,
+  AlwaysFallThrough,
+  NeverFallThroughOrReturn
+};
+
+/// CheckFallThrough - Check that we don't fall off the end of a
+/// Statement that should return a value.
+///
+/// \returns AlwaysFallThrough iff we always fall off the end of the statement,
+/// MaybeFallThrough iff we might or might not fall off the end,
+/// NeverFallThroughOrReturn iff we never fall off the end of the statement or
+/// return.  We assume NeverFallThrough iff we never fall off the end of the
+/// statement but we may return.  We assume that functions not marked noreturn
+/// will return.
+static ControlFlowKind CheckFallThrough(AnalysisDeclContext &AC) {
+  CFG *cfg = AC.getCFG();
+  if (!cfg) return UnknownFallThrough;
+
+  // The CFG leaves in dead things, and we don't want the dead code paths to
+  // confuse us, so we mark all live things first.
+  llvm::BitVector live(cfg->getNumBlockIDs());
+  unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(),
+                                                          live);
+
+  bool AddEHEdges = AC.getAddEHEdges();
+  if (!AddEHEdges && count != cfg->getNumBlockIDs())
+    // When there are things remaining dead, and we didn't add EH edges
+    // from CallExprs to the catch clauses, we have to go back and
+    // mark them as live.
+    for (const auto *B : *cfg) {
+      if (!live[B->getBlockID()]) {
+        if (B->pred_begin() == B->pred_end()) {
+          const Stmt *Term = B->getTerminatorStmt();
+          if (Term && isa<CXXTryStmt>(Term))
+            // When not adding EH edges from calls, catch clauses
+            // can otherwise seem dead.  Avoid noting them as dead.
+            count += reachable_code::ScanReachableFromBlock(B, live);
+          continue;
+        }
+      }
+    }
+
+  // Now we know what is live, we check the live precessors of the exit block
+  // and look for fall through paths, being careful to ignore normal returns,
+  // and exceptional paths.
+  bool HasLiveReturn = false;
+  bool HasFakeEdge = false;
+  bool HasPlainEdge = false;
+  bool HasAbnormalEdge = false;
+
+  // Ignore default cases that aren't likely to be reachable because all
+  // enums in a switch(X) have explicit case statements.
+  CFGBlock::FilterOptions FO;
+  FO.IgnoreDefaultsWithCoveredEnums = 1;
+
+  for (CFGBlock::filtered_pred_iterator I =
+           cfg->getExit().filtered_pred_start_end(FO);
+       I.hasMore(); ++I) {
+    const CFGBlock &B = **I;
+    if (!live[B.getBlockID()])
+      continue;
+
+    // Skip blocks which contain an element marked as no-return. They don't
+    // represent actually viable edges into the exit block, so mark them as
+    // abnormal.
+    if (B.hasNoReturnElement()) {
+      HasAbnormalEdge = true;
+      continue;
+    }
+
+    // Destructors can appear after the 'return' in the CFG.  This is
+    // normal.  We need to look pass the destructors for the return
+    // statement (if it exists).
+    CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
+
+    for ( ; ri != re ; ++ri)
+      if (ri->getAs<CFGStmt>())
+        break;
+
+    // No more CFGElements in the block?
+    if (ri == re) {
+      const Stmt *Term = B.getTerminatorStmt();
+      if (Term && (isa<CXXTryStmt>(Term) || isa<ObjCAtTryStmt>(Term))) {
+        HasAbnormalEdge = true;
+        continue;
+      }
+      // A labeled empty statement, or the entry block...
+      HasPlainEdge = true;
+      continue;
+    }
+
+    CFGStmt CS = ri->castAs<CFGStmt>();
+    const Stmt *S = CS.getStmt();
+    if (isa<ReturnStmt>(S) || isa<CoreturnStmt>(S)) {
+      HasLiveReturn = true;
+      continue;
+    }
+    if (isa<ObjCAtThrowStmt>(S)) {
+      HasFakeEdge = true;
+      continue;
+    }
+    if (isa<CXXThrowExpr>(S)) {
+      HasFakeEdge = true;
+      continue;
+    }
+    if (isa<MSAsmStmt>(S)) {
+      // TODO: Verify this is correct.
+      HasFakeEdge = true;
+      HasLiveReturn = true;
+      continue;
+    }
+    if (isa<CXXTryStmt>(S)) {
+      HasAbnormalEdge = true;
+      continue;
+    }
+    if (!llvm::is_contained(B.succs(), &cfg->getExit())) {
+      HasAbnormalEdge = true;
+      continue;
+    }
+
+    HasPlainEdge = true;
+  }
+  if (!HasPlainEdge) {
+    if (HasLiveReturn)
+      return NeverFallThrough;
+    return NeverFallThroughOrReturn;
+  }
+  if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
+    return MaybeFallThrough;
+  // This says AlwaysFallThrough for calls to functions that are not marked
+  // noreturn, that don't return.  If people would like this warning to be more
+  // accurate, such functions should be marked as noreturn.
+  return AlwaysFallThrough;
+}
+
+namespace {
+
+struct CheckFallThroughDiagnostics {
+  unsigned diag_MaybeFallThrough_HasNoReturn;
+  unsigned diag_MaybeFallThrough_ReturnsNonVoid;
+  unsigned diag_AlwaysFallThrough_HasNoReturn;
+  unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
+  unsigned diag_NeverFallThroughOrReturn;
+  enum { Function, Block, Lambda, Coroutine } funMode;
+  SourceLocation FuncLoc;
+
+  static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
+    CheckFallThroughDiagnostics D;
+    D.FuncLoc = Func->getLocation();
+    D.diag_MaybeFallThrough_HasNoReturn =
+      diag::warn_falloff_noreturn_function;
+    D.diag_MaybeFallThrough_ReturnsNonVoid =
+      diag::warn_maybe_falloff_nonvoid_function;
+    D.diag_AlwaysFallThrough_HasNoReturn =
+      diag::warn_falloff_noreturn_function;
+    D.diag_AlwaysFallThrough_ReturnsNonVoid =
+      diag::warn_falloff_nonvoid_function;
+
+    // Don't suggest that virtual functions be marked "noreturn", since they
+    // might be overridden by non-noreturn functions.
+    bool isVirtualMethod = false;
+    if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
+      isVirtualMethod = Method->isVirtual();
+
+    // Don't suggest that template instantiations be marked "noreturn"
+    bool isTemplateInstantiation = false;
+    if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
+      isTemplateInstantiation = Function->isTemplateInstantiation();
+
+    if (!isVirtualMethod && !isTemplateInstantiation)
+      D.diag_NeverFallThroughOrReturn =
+        diag::warn_suggest_noreturn_function;
+    else
+      D.diag_NeverFallThroughOrReturn = 0;
+
+    D.funMode = Function;
+    return D;
+  }
+
+  static CheckFallThroughDiagnostics MakeForCoroutine(const Decl *Func) {
+    CheckFallThroughDiagnostics D;
+    D.FuncLoc = Func->getLocation();
+    D.diag_MaybeFallThrough_HasNoReturn = 0;
+    D.diag_MaybeFallThrough_ReturnsNonVoid =
+        diag::warn_maybe_falloff_nonvoid_coroutine;
+    D.diag_AlwaysFallThrough_HasNoReturn = 0;
+    D.diag_AlwaysFallThrough_ReturnsNonVoid =
+        diag::warn_falloff_nonvoid_coroutine;
+    D.funMode = Coroutine;
+    return D;
+  }
+
+  static CheckFallThroughDiagnostics MakeForBlock() {
+    CheckFallThroughDiagnostics D;
+    D.diag_MaybeFallThrough_HasNoReturn =
+      diag::err_noreturn_block_has_return_expr;
+    D.diag_MaybeFallThrough_ReturnsNonVoid =
+      diag::err_maybe_falloff_nonvoid_block;
+    D.diag_AlwaysFallThrough_HasNoReturn =
+      diag::err_noreturn_block_has_return_expr;
+    D.diag_AlwaysFallThrough_ReturnsNonVoid =
+      diag::err_falloff_nonvoid_block;
+    D.diag_NeverFallThroughOrReturn = 0;
+    D.funMode = Block;
+    return D;
+  }
+
+  static CheckFallThroughDiagnostics MakeForLambda() {
+    CheckFallThroughDiagnostics D;
+    D.diag_MaybeFallThrough_HasNoReturn =
+      diag::err_noreturn_lambda_has_return_expr;
+    D.diag_MaybeFallThrough_ReturnsNonVoid =
+      diag::warn_maybe_falloff_nonvoid_lambda;
+    D.diag_AlwaysFallThrough_HasNoReturn =
+      diag::err_noreturn_lambda_has_return_expr;
+    D.diag_AlwaysFallThrough_ReturnsNonVoid =
+      diag::warn_falloff_nonvoid_lambda;
+    D.diag_NeverFallThroughOrReturn = 0;
+    D.funMode = Lambda;
+    return D;
+  }
+
+  bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
+                        bool HasNoReturn) const {
+    if (funMode == Function) {
+      return (ReturnsVoid ||
+              D.isIgnored(diag::warn_maybe_falloff_nonvoid_function,
+                          FuncLoc)) &&
+             (!HasNoReturn ||
+              D.isIgnored(diag::warn_noreturn_function_has_return_expr,
+                          FuncLoc)) &&
+             (!ReturnsVoid ||
+              D.isIgnored(diag::warn_suggest_noreturn_block, FuncLoc));
+    }
+    if (funMode == Coroutine) {
+      return (ReturnsVoid ||
+              D.isIgnored(diag::warn_maybe_falloff_nonvoid_function, FuncLoc) ||
+              D.isIgnored(diag::warn_maybe_falloff_nonvoid_coroutine,
+                          FuncLoc)) &&
+             (!HasNoReturn);
+    }
+    // For blocks / lambdas.
+    return ReturnsVoid && !HasNoReturn;
+  }
+};
+
+} // anonymous namespace
+
+/// CheckFallThroughForBody - Check that we don't fall off the end of a
+/// function that should return a value.  Check that we don't fall off the end
+/// of a noreturn function.  We assume that functions and blocks not marked
+/// noreturn will return.
+static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
+                                    QualType BlockType,
+                                    const CheckFallThroughDiagnostics &CD,
+                                    AnalysisDeclContext &AC,
+                                    sema::FunctionScopeInfo *FSI) {
+
+  bool ReturnsVoid = false;
+  bool HasNoReturn = false;
+  bool IsCoroutine = FSI->isCoroutine();
+
+  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+    if (const auto *CBody = dyn_cast<CoroutineBodyStmt>(Body))
+      ReturnsVoid = CBody->getFallthroughHandler() != nullptr;
+    else
+      ReturnsVoid = FD->getReturnType()->isVoidType();
+    HasNoReturn = FD->isNoReturn();
+  }
+  else if (const auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
+    ReturnsVoid = MD->getReturnType()->isVoidType();
+    HasNoReturn = MD->hasAttr<NoReturnAttr>();
+  }
+  else if (isa<BlockDecl>(D)) {
+    if (const FunctionType *FT =
+          BlockType->getPointeeType()->getAs<FunctionType>()) {
+      if (FT->getReturnType()->isVoidType())
+        ReturnsVoid = true;
+      if (FT->getNoReturnAttr())
+        HasNoReturn = true;
+    }
+  }
+
+  DiagnosticsEngine &Diags = S.getDiagnostics();
+
+  // Short circuit for compilation speed.
+  if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
+      return;
+  SourceLocation LBrace = Body->getBeginLoc(), RBrace = Body->getEndLoc();
+  auto EmitDiag = [&](SourceLocation Loc, unsigned DiagID) {
+    if (IsCoroutine)
+      S.Diag(Loc, DiagID) << FSI->CoroutinePromise->getType();
+    else
+      S.Diag(Loc, DiagID);
+  };
+
+  // cpu_dispatch functions permit empty function bodies for ICC compatibility.
+  if (D->getAsFunction() && D->getAsFunction()->isCPUDispatchMultiVersion())
+    return;
+
+  // Either in a function body compound statement, or a function-try-block.
+  switch (CheckFallThrough(AC)) {
+    case UnknownFallThrough:
+      break;
+
+    case MaybeFallThrough:
+      if (HasNoReturn)
+        EmitDiag(RBrace, CD.diag_MaybeFallThrough_HasNoReturn);
+      else if (!ReturnsVoid)
+        EmitDiag(RBrace, CD.diag_MaybeFallThrough_ReturnsNonVoid);
+      break;
+    case AlwaysFallThrough:
+      if (HasNoReturn)
+        EmitDiag(RBrace, CD.diag_AlwaysFallThrough_HasNoReturn);
+      else if (!ReturnsVoid)
+        EmitDiag(RBrace, CD.diag_AlwaysFallThrough_ReturnsNonVoid);
+      break;
+    case NeverFallThroughOrReturn:
+      if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
+        if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+          S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 0 << FD;
+        } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
+          S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 1 << MD;
+        } else {
+          S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn);
+        }
+      }
+      break;
+    case NeverFallThrough:
+      break;
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// -Wuninitialized
+//===----------------------------------------------------------------------===//
+
+namespace {
+/// ContainsReference - A visitor class to search for references to
+/// a particular declaration (the needle) within any evaluated component of an
+/// expression (recursively).
+class ContainsReference : public ConstEvaluatedExprVisitor<ContainsReference> {
+  bool FoundReference;
+  const DeclRefExpr *Needle;
+
+public:
+  typedef ConstEvaluatedExprVisitor<ContainsReference> Inherited;
+
+  ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
+    : Inherited(Context), FoundReference(false), Needle(Needle) {}
+
+  void VisitExpr(const Expr *E) {
+    // Stop evaluating if we already have a reference.
+    if (FoundReference)
+      return;
+
+    Inherited::VisitExpr(E);
+  }
+
+  void VisitDeclRefExpr(const DeclRefExpr *E) {
+    if (E == Needle)
+      FoundReference = true;
+    else
+      Inherited::VisitDeclRefExpr(E);
+  }
+
+  bool doesContainReference() const { return FoundReference; }
+};
+} // anonymous namespace
+
+static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
+  QualType VariableTy = VD->getType().getCanonicalType();
+  if (VariableTy->isBlockPointerType() &&
+      !VD->hasAttr<BlocksAttr>()) {
+    S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization)
+        << VD->getDeclName()
+        << FixItHint::CreateInsertion(VD->getLocation(), "__block ");
+    return true;
+  }
+
+  // Don't issue a fixit if there is already an initializer.
+  if (VD->getInit())
+    return false;
+
+  // Don't suggest a fixit inside macros.
+  if (VD->getEndLoc().isMacroID())
+    return false;
+
+  SourceLocation Loc = S.getLocForEndOfToken(VD->getEndLoc());
+
+  // Suggest possible initialization (if any).
+  std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
+  if (Init.empty())
+    return false;
+
+  S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
+    << FixItHint::CreateInsertion(Loc, Init);
+  return true;
+}
+
+/// Create a fixit to remove an if-like statement, on the assumption that its
+/// condition is CondVal.
+static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
+                          const Stmt *Else, bool CondVal,
+                          FixItHint &Fixit1, FixItHint &Fixit2) {
+  if (CondVal) {
+    // If condition is always true, remove all but the 'then'.
+    Fixit1 = FixItHint::CreateRemoval(
+        CharSourceRange::getCharRange(If->getBeginLoc(), Then->getBeginLoc()));
+    if (Else) {
+      SourceLocation ElseKwLoc = S.getLocForEndOfToken(Then->getEndLoc());
+      Fixit2 =
+          FixItHint::CreateRemoval(SourceRange(ElseKwLoc, Else->getEndLoc()));
+    }
+  } else {
+    // If condition is always false, remove all but the 'else'.
+    if (Else)
+      Fixit1 = FixItHint::CreateRemoval(CharSourceRange::getCharRange(
+          If->getBeginLoc(), Else->getBeginLoc()));
+    else
+      Fixit1 = FixItHint::CreateRemoval(If->getSourceRange());
+  }
+}
+
+/// DiagUninitUse -- Helper function to produce a diagnostic for an
+/// uninitialized use of a variable.
+static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
+                          bool IsCapturedByBlock) {
+  bool Diagnosed = false;
+
+  switch (Use.getKind()) {
+  case UninitUse::Always:
+    S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_var)
+        << VD->getDeclName() << IsCapturedByBlock
+        << Use.getUser()->getSourceRange();
+    return;
+
+  case UninitUse::AfterDecl:
+  case UninitUse::AfterCall:
+    S.Diag(VD->getLocation(), diag::warn_sometimes_uninit_var)
+      << VD->getDeclName() << IsCapturedByBlock
+      << (Use.getKind() == UninitUse::AfterDecl ? 4 : 5)
+      << const_cast<DeclContext*>(VD->getLexicalDeclContext())
+      << VD->getSourceRange();
+    S.Diag(Use.getUser()->getBeginLoc(), diag::note_uninit_var_use)
+        << IsCapturedByBlock << Use.getUser()->getSourceRange();
+    return;
+
+  case UninitUse::Maybe:
+  case UninitUse::Sometimes:
+    // Carry on to report sometimes-uninitialized branches, if possible,
+    // or a 'may be used uninitialized' diagnostic otherwise.
+    break;
+  }
+
+  // Diagnose each branch which leads to a sometimes-uninitialized use.
+  for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
+       I != E; ++I) {
+    assert(Use.getKind() == UninitUse::Sometimes);
+
+    const Expr *User = Use.getUser();
+    const Stmt *Term = I->Terminator;
+
+    // Information used when building the diagnostic.
+    unsigned DiagKind;
+    StringRef Str;
+    SourceRange Range;
+
+    // FixIts to suppress the diagnostic by removing the dead condition.
+    // For all binary terminators, branch 0 is taken if the condition is true,
+    // and branch 1 is taken if the condition is false.
+    int RemoveDiagKind = -1;
+    const char *FixitStr =
+        S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
+                                  : (I->Output ? "1" : "0");
+    FixItHint Fixit1, Fixit2;
+
+    switch (Term ? Term->getStmtClass() : Stmt::DeclStmtClass) {
+    default:
+      // Don't know how to report this. Just fall back to 'may be used
+      // uninitialized'. FIXME: Can this happen?
+      continue;
+
+    // "condition is true / condition is false".
+    case Stmt::IfStmtClass: {
+      const IfStmt *IS = cast<IfStmt>(Term);
+      DiagKind = 0;
+      Str = "if";
+      Range = IS->getCond()->getSourceRange();
+      RemoveDiagKind = 0;
+      CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
+                    I->Output, Fixit1, Fixit2);
+      break;
+    }
+    case Stmt::ConditionalOperatorClass: {
+      const ConditionalOperator *CO = cast<ConditionalOperator>(Term);
+      DiagKind = 0;
+      Str = "?:";
+      Range = CO->getCond()->getSourceRange();
+      RemoveDiagKind = 0;
+      CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
+                    I->Output, Fixit1, Fixit2);
+      break;
+    }
+    case Stmt::BinaryOperatorClass: {
+      const BinaryOperator *BO = cast<BinaryOperator>(Term);
+      if (!BO->isLogicalOp())
+        continue;
+      DiagKind = 0;
+      Str = BO->getOpcodeStr();
+      Range = BO->getLHS()->getSourceRange();
+      RemoveDiagKind = 0;
+      if ((BO->getOpcode() == BO_LAnd && I->Output) ||
+          (BO->getOpcode() == BO_LOr && !I->Output))
+        // true && y -> y, false || y -> y.
+        Fixit1 = FixItHint::CreateRemoval(
+            SourceRange(BO->getBeginLoc(), BO->getOperatorLoc()));
+      else
+        // false && y -> false, true || y -> true.
+        Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
+      break;
+    }
+
+    // "loop is entered / loop is exited".
+    case Stmt::WhileStmtClass:
+      DiagKind = 1;
+      Str = "while";
+      Range = cast<WhileStmt>(Term)->getCond()->getSourceRange();
+      RemoveDiagKind = 1;
+      Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
+      break;
+    case Stmt::ForStmtClass:
+      DiagKind = 1;
+      Str = "for";
+      Range = cast<ForStmt>(Term)->getCond()->getSourceRange();
+      RemoveDiagKind = 1;
+      if (I->Output)
+        Fixit1 = FixItHint::CreateRemoval(Range);
+      else
+        Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
+      break;
+    case Stmt::CXXForRangeStmtClass:
+      if (I->Output == 1) {
+        // The use occurs if a range-based for loop's body never executes.
+        // That may be impossible, and there's no syntactic fix for this,
+        // so treat it as a 'may be uninitialized' case.
+        continue;
+      }
+      DiagKind = 1;
+      Str = "for";
+      Range = cast<CXXForRangeStmt>(Term)->getRangeInit()->getSourceRange();
+      break;
+
+    // "condition is true / loop is exited".
+    case Stmt::DoStmtClass:
+      DiagKind = 2;
+      Str = "do";
+      Range = cast<DoStmt>(Term)->getCond()->getSourceRange();
+      RemoveDiagKind = 1;
+      Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
+      break;
+
+    // "switch case is taken".
+    case Stmt::CaseStmtClass:
+      DiagKind = 3;
+      Str = "case";
+      Range = cast<CaseStmt>(Term)->getLHS()->getSourceRange();
+      break;
+    case Stmt::DefaultStmtClass:
+      DiagKind = 3;
+      Str = "default";
+      Range = cast<DefaultStmt>(Term)->getDefaultLoc();
+      break;
+    }
+
+    S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
+      << VD->getDeclName() << IsCapturedByBlock << DiagKind
+      << Str << I->Output << Range;
+    S.Diag(User->getBeginLoc(), diag::note_uninit_var_use)
+        << IsCapturedByBlock << User->getSourceRange();
+    if (RemoveDiagKind != -1)
+      S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
+        << RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
+
+    Diagnosed = true;
+  }
+
+  if (!Diagnosed)
+    S.Diag(Use.getUser()->getBeginLoc(), diag::warn_maybe_uninit_var)
+        << VD->getDeclName() << IsCapturedByBlock
+        << Use.getUser()->getSourceRange();
+}
+
+/// Diagnose uninitialized const reference usages.
+static bool DiagnoseUninitializedConstRefUse(Sema &S, const VarDecl *VD,
+                                             const UninitUse &Use) {
+  S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_const_reference)
+      << VD->getDeclName() << Use.getUser()->getSourceRange();
+  return true;
+}
+
+/// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
+/// uninitialized variable. This manages the different forms of diagnostic
+/// emitted for particular types of uses. Returns true if the use was diagnosed
+/// as a warning. If a particular use is one we omit warnings for, returns
+/// false.
+static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
+                                     const UninitUse &Use,
+                                     bool alwaysReportSelfInit = false) {
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
+    // Inspect the initializer of the variable declaration which is
+    // being referenced prior to its initialization. We emit
+    // specialized diagnostics for self-initialization, and we
+    // specifically avoid warning about self references which take the
+    // form of:
+    //
+    //   int x = x;
+    //
+    // This is used to indicate to GCC that 'x' is intentionally left
+    // uninitialized. Proven code paths which access 'x' in
+    // an uninitialized state after this will still warn.
+    if (const Expr *Initializer = VD->getInit()) {
+      if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
+        return false;
+
+      ContainsReference CR(S.Context, DRE);
+      CR.Visit(Initializer);
+      if (CR.doesContainReference()) {
+        S.Diag(DRE->getBeginLoc(), diag::warn_uninit_self_reference_in_init)
+            << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
+        return true;
+      }
+    }
+
+    DiagUninitUse(S, VD, Use, false);
+  } else {
+    const BlockExpr *BE = cast<BlockExpr>(Use.getUser());
+    if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
+      S.Diag(BE->getBeginLoc(),
+             diag::warn_uninit_byref_blockvar_captured_by_block)
+          << VD->getDeclName()
+          << VD->getType().getQualifiers().hasObjCLifetime();
+    else
+      DiagUninitUse(S, VD, Use, true);
+  }
+
+  // Report where the variable was declared when the use wasn't within
+  // the initializer of that declaration & we didn't already suggest
+  // an initialization fixit.
+  if (!SuggestInitializationFixit(S, VD))
+    S.Diag(VD->getBeginLoc(), diag::note_var_declared_here)
+        << VD->getDeclName();
+
+  return true;
+}
+
+namespace {
+  class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
+  public:
+    FallthroughMapper(Sema &S)
+      : FoundSwitchStatements(false),
+        S(S) {
+    }
+
+    bool foundSwitchStatements() const { return FoundSwitchStatements; }
+
+    void markFallthroughVisited(const AttributedStmt *Stmt) {
+      bool Found = FallthroughStmts.erase(Stmt);
+      assert(Found);
+      (void)Found;
+    }
+
+    typedef llvm::SmallPtrSet<const AttributedStmt*, 8> AttrStmts;
+
+    const AttrStmts &getFallthroughStmts() const {
+      return FallthroughStmts;
+    }
+
+    void fillReachableBlocks(CFG *Cfg) {
+      assert(ReachableBlocks.empty() && "ReachableBlocks already filled");
+      std::deque<const CFGBlock *> BlockQueue;
+
+      ReachableBlocks.insert(&Cfg->getEntry());
+      BlockQueue.push_back(&Cfg->getEntry());
+      // Mark all case blocks reachable to avoid problems with switching on
+      // constants, covered enums, etc.
+      // These blocks can contain fall-through annotations, and we don't want to
+      // issue a warn_fallthrough_attr_unreachable for them.
+      for (const auto *B : *Cfg) {
+        const Stmt *L = B->getLabel();
+        if (L && isa<SwitchCase>(L) && ReachableBlocks.insert(B).second)
+          BlockQueue.push_back(B);
+      }
+
+      while (!BlockQueue.empty()) {
+        const CFGBlock *P = BlockQueue.front();
+        BlockQueue.pop_front();
+        for (const CFGBlock *B : P->succs()) {
+          if (B && ReachableBlocks.insert(B).second)
+            BlockQueue.push_back(B);
+        }
+      }
+    }
+
+    bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt,
+                                   bool IsTemplateInstantiation) {
+      assert(!ReachableBlocks.empty() && "ReachableBlocks empty");
+
+      int UnannotatedCnt = 0;
+      AnnotatedCnt = 0;
+
+      std::deque<const CFGBlock*> BlockQueue(B.pred_begin(), B.pred_end());
+      while (!BlockQueue.empty()) {
+        const CFGBlock *P = BlockQueue.front();
+        BlockQueue.pop_front();
+        if (!P) continue;
+
+        const Stmt *Term = P->getTerminatorStmt();
+        if (Term && isa<SwitchStmt>(Term))
+          continue; // Switch statement, good.
+
+        const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
+        if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
+          continue; // Previous case label has no statements, good.
+
+        const LabelStmt *L = dyn_cast_or_null<LabelStmt>(P->getLabel());
+        if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
+          continue; // Case label is preceded with a normal label, good.
+
+        if (!ReachableBlocks.count(P)) {
+          for (const CFGElement &Elem : llvm::reverse(*P)) {
+            if (std::optional<CFGStmt> CS = Elem.getAs<CFGStmt>()) {
+            if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
+              // Don't issue a warning for an unreachable fallthrough
+              // attribute in template instantiations as it may not be
+              // unreachable in all instantiations of the template.
+              if (!IsTemplateInstantiation)
+                S.Diag(AS->getBeginLoc(),
+                       diag::warn_unreachable_fallthrough_attr);
+              markFallthroughVisited(AS);
+              ++AnnotatedCnt;
+              break;
+            }
+            // Don't care about other unreachable statements.
+            }
+          }
+          // If there are no unreachable statements, this may be a special
+          // case in CFG:
+          // case X: {
+          //    A a;  // A has a destructor.
+          //    break;
+          // }
+          // // <<<< This place is represented by a 'hanging' CFG block.
+          // case Y:
+          continue;
+        }
+
+        const Stmt *LastStmt = getLastStmt(*P);
+        if (const AttributedStmt *AS = asFallThroughAttr(LastStmt)) {
+          markFallthroughVisited(AS);
+          ++AnnotatedCnt;
+          continue; // Fallthrough annotation, good.
+        }
+
+        if (!LastStmt) { // This block contains no executable statements.
+          // Traverse its predecessors.
+          std::copy(P->pred_begin(), P->pred_end(),
+                    std::back_inserter(BlockQueue));
+          continue;
+        }
+
+        ++UnannotatedCnt;
+      }
+      return !!UnannotatedCnt;
+    }
+
+    // RecursiveASTVisitor setup.
+    bool shouldWalkTypesOfTypeLocs() const { return false; }
+
+    bool VisitAttributedStmt(AttributedStmt *S) {
+      if (asFallThroughAttr(S))
+        FallthroughStmts.insert(S);
+      return true;
+    }
+
+    bool VisitSwitchStmt(SwitchStmt *S) {
+      FoundSwitchStatements = true;
+      return true;
+    }
+
+    // We don't want to traverse local type declarations. We analyze their
+    // methods separately.
+    bool TraverseDecl(Decl *D) { return true; }
+
+    // We analyze lambda bodies separately. Skip them here.
+    bool TraverseLambdaExpr(LambdaExpr *LE) {
+      // Traverse the captures, but not the body.
+      for (const auto C : zip(LE->captures(), LE->capture_inits()))
+        TraverseLambdaCapture(LE, &std::get<0>(C), std::get<1>(C));
+      return true;
+    }
+
+  private:
+
+    static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
+      if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(S)) {
+        if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
+          return AS;
+      }
+      return nullptr;
+    }
+
+    static const Stmt *getLastStmt(const CFGBlock &B) {
+      if (const Stmt *Term = B.getTerminatorStmt())
+        return Term;
+      for (const CFGElement &Elem : llvm::reverse(B))
+        if (std::optional<CFGStmt> CS = Elem.getAs<CFGStmt>())
+          return CS->getStmt();
+      // Workaround to detect a statement thrown out by CFGBuilder:
+      //   case X: {} case Y:
+      //   case X: ; case Y:
+      if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(B.getLabel()))
+        if (!isa<SwitchCase>(SW->getSubStmt()))
+          return SW->getSubStmt();
+
+      return nullptr;
+    }
+
+    bool FoundSwitchStatements;
+    AttrStmts FallthroughStmts;
+    Sema &S;
+    llvm::SmallPtrSet<const CFGBlock *, 16> ReachableBlocks;
+  };
+} // anonymous namespace
+
+static StringRef getFallthroughAttrSpelling(Preprocessor &PP,
+                                            SourceLocation Loc) {
+  TokenValue FallthroughTokens[] = {
+    tok::l_square, tok::l_square,
+    PP.getIdentifierInfo("fallthrough"),
+    tok::r_square, tok::r_square
+  };
+
+  TokenValue ClangFallthroughTokens[] = {
+    tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
+    tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
+    tok::r_square, tok::r_square
+  };
+
+  bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17 && !PP.getLangOpts().C2x;
+
+  StringRef MacroName;
+  if (PreferClangAttr)
+    MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
+  if (MacroName.empty())
+    MacroName = PP.getLastMacroWithSpelling(Loc, FallthroughTokens);
+  if (MacroName.empty() && !PreferClangAttr)
+    MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
+  if (MacroName.empty()) {
+    if (!PreferClangAttr)
+      MacroName = "[[fallthrough]]";
+    else if (PP.getLangOpts().CPlusPlus)
+      MacroName = "[[clang::fallthrough]]";
+    else
+      MacroName = "__attribute__((fallthrough))";
+  }
+  return MacroName;
+}
+
+static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
+                                            bool PerFunction) {
+  FallthroughMapper FM(S);
+  FM.TraverseStmt(AC.getBody());
+
+  if (!FM.foundSwitchStatements())
+    return;
+
+  if (PerFunction && FM.getFallthroughStmts().empty())
+    return;
+
+  CFG *Cfg = AC.getCFG();
+
+  if (!Cfg)
+    return;
+
+  FM.fillReachableBlocks(Cfg);
+
+  for (const CFGBlock *B : llvm::reverse(*Cfg)) {
+    const Stmt *Label = B->getLabel();
+
+    if (!isa_and_nonnull<SwitchCase>(Label))
+      continue;
+
+    int AnnotatedCnt;
+
+    bool IsTemplateInstantiation = false;
+    if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(AC.getDecl()))
+      IsTemplateInstantiation = Function->isTemplateInstantiation();
+    if (!FM.checkFallThroughIntoBlock(*B, AnnotatedCnt,
+                                      IsTemplateInstantiation))
+      continue;
+
+    S.Diag(Label->getBeginLoc(),
+           PerFunction ? diag::warn_unannotated_fallthrough_per_function
+                       : diag::warn_unannotated_fallthrough);
+
+    if (!AnnotatedCnt) {
+      SourceLocation L = Label->getBeginLoc();
+      if (L.isMacroID())
+        continue;
+
+      const Stmt *Term = B->getTerminatorStmt();
+      // Skip empty cases.
+      while (B->empty() && !Term && B->succ_size() == 1) {
+        B = *B->succ_begin();
+        Term = B->getTerminatorStmt();
+      }
+      if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
+        Preprocessor &PP = S.getPreprocessor();
+        StringRef AnnotationSpelling = getFallthroughAttrSpelling(PP, L);
+        SmallString<64> TextToInsert(AnnotationSpelling);
+        TextToInsert += "; ";
+        S.Diag(L, diag::note_insert_fallthrough_fixit)
+            << AnnotationSpelling
+            << FixItHint::CreateInsertion(L, TextToInsert);
+      }
+      S.Diag(L, diag::note_insert_break_fixit)
+          << FixItHint::CreateInsertion(L, "break; ");
+    }
+  }
+
+  for (const auto *F : FM.getFallthroughStmts())
+    S.Diag(F->getBeginLoc(), diag::err_fallthrough_attr_invalid_placement);
+}
+
+static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
+                     const Stmt *S) {
+  assert(S);
+
+  do {
+    switch (S->getStmtClass()) {
+    case Stmt::ForStmtClass:
+    case Stmt::WhileStmtClass:
+    case Stmt::CXXForRangeStmtClass:
+    case Stmt::ObjCForCollectionStmtClass:
+      return true;
+    case Stmt::DoStmtClass: {
+      Expr::EvalResult Result;
+      if (!cast<DoStmt>(S)->getCond()->EvaluateAsInt(Result, Ctx))
+        return true;
+      return Result.Val.getInt().getBoolValue();
+    }
+    default:
+      break;
+    }
+  } while ((S = PM.getParent(S)));
+
+  return false;
+}
+
+static void diagnoseRepeatedUseOfWeak(Sema &S,
+                                      const sema::FunctionScopeInfo *CurFn,
+                                      const Decl *D,
+                                      const ParentMap &PM) {
+  typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
+  typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
+  typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
+  typedef std::pair<const Stmt *, WeakObjectUseMap::const_iterator>
+  StmtUsesPair;
+
+  ASTContext &Ctx = S.getASTContext();
+
+  const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
+
+  // Extract all weak objects that are referenced more than once.
+  SmallVector<StmtUsesPair, 8> UsesByStmt;
+  for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
+       I != E; ++I) {
+    const WeakUseVector &Uses = I->second;
+
+    // Find the first read of the weak object.
+    WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
+    for ( ; UI != UE; ++UI) {
+      if (UI->isUnsafe())
+        break;
+    }
+
+    // If there were only writes to this object, don't warn.
+    if (UI == UE)
+      continue;
+
+    // If there was only one read, followed by any number of writes, and the
+    // read is not within a loop, don't warn. Additionally, don't warn in a
+    // loop if the base object is a local variable -- local variables are often
+    // changed in loops.
+    if (UI == Uses.begin()) {
+      WeakUseVector::const_iterator UI2 = UI;
+      for (++UI2; UI2 != UE; ++UI2)
+        if (UI2->isUnsafe())
+          break;
+
+      if (UI2 == UE) {
+        if (!isInLoop(Ctx, PM, UI->getUseExpr()))
+          continue;
+
+        const WeakObjectProfileTy &Profile = I->first;
+        if (!Profile.isExactProfile())
+          continue;
+
+        const NamedDecl *Base = Profile.getBase();
+        if (!Base)
+          Base = Profile.getProperty();
+        assert(Base && "A profile always has a base or property.");
+
+        if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Base))
+          if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Base))
+            continue;
+      }
+    }
+
+    UsesByStmt.push_back(StmtUsesPair(UI->getUseExpr(), I));
+  }
+
+  if (UsesByStmt.empty())
+    return;
+
+  // Sort by first use so that we emit the warnings in a deterministic order.
+  SourceManager &SM = S.getSourceManager();
+  llvm::sort(UsesByStmt,
+             [&SM](const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
+               return SM.isBeforeInTranslationUnit(LHS.first->getBeginLoc(),
+                                                   RHS.first->getBeginLoc());
+             });
+
+  // Classify the current code body for better warning text.
+  // This enum should stay in sync with the cases in
+  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
+  // FIXME: Should we use a common classification enum and the same set of
+  // possibilities all throughout Sema?
+  enum {
+    Function,
+    Method,
+    Block,
+    Lambda
+  } FunctionKind;
+
+  if (isa<sema::BlockScopeInfo>(CurFn))
+    FunctionKind = Block;
+  else if (isa<sema::LambdaScopeInfo>(CurFn))
+    FunctionKind = Lambda;
+  else if (isa<ObjCMethodDecl>(D))
+    FunctionKind = Method;
+  else
+    FunctionKind = Function;
+
+  // Iterate through the sorted problems and emit warnings for each.
+  for (const auto &P : UsesByStmt) {
+    const Stmt *FirstRead = P.first;
+    const WeakObjectProfileTy &Key = P.second->first;
+    const WeakUseVector &Uses = P.second->second;
+
+    // For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
+    // may not contain enough information to determine that these are different
+    // properties. We can only be 100% sure of a repeated use in certain cases,
+    // and we adjust the diagnostic kind accordingly so that the less certain
+    // case can be turned off if it is too noisy.
+    unsigned DiagKind;
+    if (Key.isExactProfile())
+      DiagKind = diag::warn_arc_repeated_use_of_weak;
+    else
+      DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
+
+    // Classify the weak object being accessed for better warning text.
+    // This enum should stay in sync with the cases in
+    // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
+    enum {
+      Variable,
+      Property,
+      ImplicitProperty,
+      Ivar
+    } ObjectKind;
+
+    const NamedDecl *KeyProp = Key.getProperty();
+    if (isa<VarDecl>(KeyProp))
+      ObjectKind = Variable;
+    else if (isa<ObjCPropertyDecl>(KeyProp))
+      ObjectKind = Property;
+    else if (isa<ObjCMethodDecl>(KeyProp))
+      ObjectKind = ImplicitProperty;
+    else if (isa<ObjCIvarDecl>(KeyProp))
+      ObjectKind = Ivar;
+    else
+      llvm_unreachable("Unexpected weak object kind!");
+
+    // Do not warn about IBOutlet weak property receivers being set to null
+    // since they are typically only used from the main thread.
+    if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(KeyProp))
+      if (Prop->hasAttr<IBOutletAttr>())
+        continue;
+
+    // Show the first time the object was read.
+    S.Diag(FirstRead->getBeginLoc(), DiagKind)
+        << int(ObjectKind) << KeyProp << int(FunctionKind)
+        << FirstRead->getSourceRange();
+
+    // Print all the other accesses as notes.
+    for (const auto &Use : Uses) {
+      if (Use.getUseExpr() == FirstRead)
+        continue;
+      S.Diag(Use.getUseExpr()->getBeginLoc(),
+             diag::note_arc_weak_also_accessed_here)
+          << Use.getUseExpr()->getSourceRange();
+    }
+  }
+}
+
+namespace clang {
+namespace {
+typedef SmallVector<PartialDiagnosticAt, 1> OptionalNotes;
+typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
+typedef std::list<DelayedDiag> DiagList;
+
+struct SortDiagBySourceLocation {
+  SourceManager &SM;
+  SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
+
+  bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
+    // Although this call will be slow, this is only called when outputting
+    // multiple warnings.
+    return SM.isBeforeInTranslationUnit(left.first.first, right.first.first);
+  }
+};
+} // anonymous namespace
+} // namespace clang
+
+namespace {
+class UninitValsDiagReporter : public UninitVariablesHandler {
+  Sema &S;
+  typedef SmallVector<UninitUse, 2> UsesVec;
+  typedef llvm::PointerIntPair<UsesVec *, 1, bool> MappedType;
+  // Prefer using MapVector to DenseMap, so that iteration order will be
+  // the same as insertion order. This is needed to obtain a deterministic
+  // order of diagnostics when calling flushDiagnostics().
+  typedef llvm::MapVector<const VarDecl *, MappedType> UsesMap;
+  UsesMap uses;
+  UsesMap constRefUses;
+
+public:
+  UninitValsDiagReporter(Sema &S) : S(S) {}
+  ~UninitValsDiagReporter() override { flushDiagnostics(); }
+
+  MappedType &getUses(UsesMap &um, const VarDecl *vd) {
+    MappedType &V = um[vd];
+    if (!V.getPointer())
+      V.setPointer(new UsesVec());
+    return V;
+  }
+
+  void handleUseOfUninitVariable(const VarDecl *vd,
+                                 const UninitUse &use) override {
+    getUses(uses, vd).getPointer()->push_back(use);
+  }
+
+  void handleConstRefUseOfUninitVariable(const VarDecl *vd,
+                                         const UninitUse &use) override {
+    getUses(constRefUses, vd).getPointer()->push_back(use);
+  }
+
+  void handleSelfInit(const VarDecl *vd) override {
+    getUses(uses, vd).setInt(true);
+    getUses(constRefUses, vd).setInt(true);
+  }
+
+  void flushDiagnostics() {
+    for (const auto &P : uses) {
+      const VarDecl *vd = P.first;
+      const MappedType &V = P.second;
+
+      UsesVec *vec = V.getPointer();
+      bool hasSelfInit = V.getInt();
+
+      // Specially handle the case where we have uses of an uninitialized
+      // variable, but the root cause is an idiomatic self-init.  We want
+      // to report the diagnostic at the self-init since that is the root cause.
+      if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
+        DiagnoseUninitializedUse(S, vd,
+                                 UninitUse(vd->getInit()->IgnoreParenCasts(),
+                                           /* isAlwaysUninit */ true),
+                                 /* alwaysReportSelfInit */ true);
+      else {
+        // Sort the uses by their SourceLocations.  While not strictly
+        // guaranteed to produce them in line/column order, this will provide
+        // a stable ordering.
+        llvm::sort(*vec, [](const UninitUse &a, const UninitUse &b) {
+          // Prefer a more confident report over a less confident one.
+          if (a.getKind() != b.getKind())
+            return a.getKind() > b.getKind();
+          return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
+        });
+
+        for (const auto &U : *vec) {
+          // If we have self-init, downgrade all uses to 'may be uninitialized'.
+          UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
+
+          if (DiagnoseUninitializedUse(S, vd, Use))
+            // Skip further diagnostics for this variable. We try to warn only
+            // on the first point at which a variable is used uninitialized.
+            break;
+        }
+      }
+
+      // Release the uses vector.
+      delete vec;
+    }
+
+    uses.clear();
+
+    // Flush all const reference uses diags.
+    for (const auto &P : constRefUses) {
+      const VarDecl *vd = P.first;
+      const MappedType &V = P.second;
+
+      UsesVec *vec = V.getPointer();
+      bool hasSelfInit = V.getInt();
+
+      if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
+        DiagnoseUninitializedUse(S, vd,
+                                 UninitUse(vd->getInit()->IgnoreParenCasts(),
+                                           /* isAlwaysUninit */ true),
+                                 /* alwaysReportSelfInit */ true);
+      else {
+        for (const auto &U : *vec) {
+          if (DiagnoseUninitializedConstRefUse(S, vd, U))
+            break;
+        }
+      }
+
+      // Release the uses vector.
+      delete vec;
+    }
+
+    constRefUses.clear();
+  }
+
+private:
+  static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
+    return llvm::any_of(*vec, [](const UninitUse &U) {
+      return U.getKind() == UninitUse::Always ||
+             U.getKind() == UninitUse::AfterCall ||
+             U.getKind() == UninitUse::AfterDecl;
+    });
+  }
+};
+
+/// Inter-procedural data for the called-once checker.
+class CalledOnceInterProceduralData {
+public:
+  // Add the delayed warning for the given block.
+  void addDelayedWarning(const BlockDecl *Block,
+                         PartialDiagnosticAt &&Warning) {
+    DelayedBlockWarnings[Block].emplace_back(std::move(Warning));
+  }
+  // Report all of the warnings we've gathered for the given block.
+  void flushWarnings(const BlockDecl *Block, Sema &S) {
+    for (const PartialDiagnosticAt &Delayed : DelayedBlockWarnings[Block])
+      S.Diag(Delayed.first, Delayed.second);
+
+    discardWarnings(Block);
+  }
+  // Discard all of the warnings we've gathered for the given block.
+  void discardWarnings(const BlockDecl *Block) {
+    DelayedBlockWarnings.erase(Block);
+  }
+
+private:
+  using DelayedDiagnostics = SmallVector<PartialDiagnosticAt, 2>;
+  llvm::DenseMap<const BlockDecl *, DelayedDiagnostics> DelayedBlockWarnings;
+};
+
+class CalledOnceCheckReporter : public CalledOnceCheckHandler {
+public:
+  CalledOnceCheckReporter(Sema &S, CalledOnceInterProceduralData &Data)
+      : S(S), Data(Data) {}
+  void handleDoubleCall(const ParmVarDecl *Parameter, const Expr *Call,
+                        const Expr *PrevCall, bool IsCompletionHandler,
+                        bool Poised) override {
+    auto DiagToReport = IsCompletionHandler
+                            ? diag::warn_completion_handler_called_twice
+                            : diag::warn_called_once_gets_called_twice;
+    S.Diag(Call->getBeginLoc(), DiagToReport) << Parameter;
+    S.Diag(PrevCall->getBeginLoc(), diag::note_called_once_gets_called_twice)
+        << Poised;
+  }
+
+  void handleNeverCalled(const ParmVarDecl *Parameter,
+                         bool IsCompletionHandler) override {
+    auto DiagToReport = IsCompletionHandler
+                            ? diag::warn_completion_handler_never_called
+                            : diag::warn_called_once_never_called;
+    S.Diag(Parameter->getBeginLoc(), DiagToReport)
+        << Parameter << /* Captured */ false;
+  }
+
+  void handleNeverCalled(const ParmVarDecl *Parameter, const Decl *Function,
+                         const Stmt *Where, NeverCalledReason Reason,
+                         bool IsCalledDirectly,
+                         bool IsCompletionHandler) override {
+    auto DiagToReport = IsCompletionHandler
+                            ? diag::warn_completion_handler_never_called_when
+                            : diag::warn_called_once_never_called_when;
+    PartialDiagnosticAt Warning(Where->getBeginLoc(), S.PDiag(DiagToReport)
+                                                          << Parameter
+                                                          << IsCalledDirectly
+                                                          << (unsigned)Reason);
+
+    if (const auto *Block = dyn_cast<BlockDecl>(Function)) {
+      // We shouldn't report these warnings on blocks immediately
+      Data.addDelayedWarning(Block, std::move(Warning));
+    } else {
+      S.Diag(Warning.first, Warning.second);
+    }
+  }
+
+  void handleCapturedNeverCalled(const ParmVarDecl *Parameter,
+                                 const Decl *Where,
+                                 bool IsCompletionHandler) override {
+    auto DiagToReport = IsCompletionHandler
+                            ? diag::warn_completion_handler_never_called
+                            : diag::warn_called_once_never_called;
+    S.Diag(Where->getBeginLoc(), DiagToReport)
+        << Parameter << /* Captured */ true;
+  }
+
+  void
+  handleBlockThatIsGuaranteedToBeCalledOnce(const BlockDecl *Block) override {
+    Data.flushWarnings(Block, S);
+  }
+
+  void handleBlockWithNoGuarantees(const BlockDecl *Block) override {
+    Data.discardWarnings(Block);
+  }
+
+private:
+  Sema &S;
+  CalledOnceInterProceduralData &Data;
+};
+
+constexpr unsigned CalledOnceWarnings[] = {
+    diag::warn_called_once_never_called,
+    diag::warn_called_once_never_called_when,
+    diag::warn_called_once_gets_called_twice};
+
+constexpr unsigned CompletionHandlerWarnings[]{
+    diag::warn_completion_handler_never_called,
+    diag::warn_completion_handler_never_called_when,
+    diag::warn_completion_handler_called_twice};
+
+bool shouldAnalyzeCalledOnceImpl(llvm::ArrayRef<unsigned> DiagIDs,
+                                 const DiagnosticsEngine &Diags,
+                                 SourceLocation At) {
+  return llvm::any_of(DiagIDs, [&Diags, At](unsigned DiagID) {
+    return !Diags.isIgnored(DiagID, At);
+  });
+}
+
+bool shouldAnalyzeCalledOnceConventions(const DiagnosticsEngine &Diags,
+                                        SourceLocation At) {
+  return shouldAnalyzeCalledOnceImpl(CompletionHandlerWarnings, Diags, At);
+}
+
+bool shouldAnalyzeCalledOnceParameters(const DiagnosticsEngine &Diags,
+                                       SourceLocation At) {
+  return shouldAnalyzeCalledOnceImpl(CalledOnceWarnings, Diags, At) ||
+         shouldAnalyzeCalledOnceConventions(Diags, At);
+}
+} // anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// -Wthread-safety
+//===----------------------------------------------------------------------===//
+namespace clang {
+namespace threadSafety {
+namespace {
+class ThreadSafetyReporter : public clang::threadSafety::ThreadSafetyHandler {
+  Sema &S;
+  DiagList Warnings;
+  SourceLocation FunLocation, FunEndLocation;
+
+  const FunctionDecl *CurrentFunction;
+  bool Verbose;
+
+  OptionalNotes getNotes() const {
+    if (Verbose && CurrentFunction) {
+      PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
+                                S.PDiag(diag::note_thread_warning_in_fun)
+                                    << CurrentFunction);
+      return OptionalNotes(1, FNote);
+    }
+    return OptionalNotes();
+  }
+
+  OptionalNotes getNotes(const PartialDiagnosticAt &Note) const {
+    OptionalNotes ONS(1, Note);
+    if (Verbose && CurrentFunction) {
+      PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
+                                S.PDiag(diag::note_thread_warning_in_fun)
+                                    << CurrentFunction);
+      ONS.push_back(std::move(FNote));
+    }
+    return ONS;
+  }
+
+  OptionalNotes getNotes(const PartialDiagnosticAt &Note1,
+                         const PartialDiagnosticAt &Note2) const {
+    OptionalNotes ONS;
+    ONS.push_back(Note1);
+    ONS.push_back(Note2);
+    if (Verbose && CurrentFunction) {
+      PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
+                                S.PDiag(diag::note_thread_warning_in_fun)
+                                    << CurrentFunction);
+      ONS.push_back(std::move(FNote));
+    }
+    return ONS;
+  }
+
+  OptionalNotes makeLockedHereNote(SourceLocation LocLocked, StringRef Kind) {
+    return LocLocked.isValid()
+               ? getNotes(PartialDiagnosticAt(
+                     LocLocked, S.PDiag(diag::note_locked_here) << Kind))
+               : getNotes();
+  }
+
+  OptionalNotes makeUnlockedHereNote(SourceLocation LocUnlocked,
+                                     StringRef Kind) {
+    return LocUnlocked.isValid()
+               ? getNotes(PartialDiagnosticAt(
+                     LocUnlocked, S.PDiag(diag::note_unlocked_here) << Kind))
+               : getNotes();
+  }
+
+ public:
+  ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
+    : S(S), FunLocation(FL), FunEndLocation(FEL),
+      CurrentFunction(nullptr), Verbose(false) {}
+
+  void setVerbose(bool b) { Verbose = b; }
+
+  /// Emit all buffered diagnostics in order of sourcelocation.
+  /// We need to output diagnostics produced while iterating through
+  /// the lockset in deterministic order, so this function orders diagnostics
+  /// and outputs them.
+  void emitDiagnostics() {
+    Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
+    for (const auto &Diag : Warnings) {
+      S.Diag(Diag.first.first, Diag.first.second);
+      for (const auto &Note : Diag.second)
+        S.Diag(Note.first, Note.second);
+    }
+  }
+
+  void handleInvalidLockExp(SourceLocation Loc) override {
+    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_cannot_resolve_lock)
+                                         << Loc);
+    Warnings.emplace_back(std::move(Warning), getNotes());
+  }
+
+  void handleUnmatchedUnlock(StringRef Kind, Name LockName, SourceLocation Loc,
+                             SourceLocation LocPreviousUnlock) override {
+    if (Loc.isInvalid())
+      Loc = FunLocation;
+    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_unlock_but_no_lock)
+                                         << Kind << LockName);
+    Warnings.emplace_back(std::move(Warning),
+                          makeUnlockedHereNote(LocPreviousUnlock, Kind));
+  }
+
+  void handleIncorrectUnlockKind(StringRef Kind, Name LockName,
+                                 LockKind Expected, LockKind Received,
+                                 SourceLocation LocLocked,
+                                 SourceLocation LocUnlock) override {
+    if (LocUnlock.isInvalid())
+      LocUnlock = FunLocation;
+    PartialDiagnosticAt Warning(
+        LocUnlock, S.PDiag(diag::warn_unlock_kind_mismatch)
+                       << Kind << LockName << Received << Expected);
+    Warnings.emplace_back(std::move(Warning),
+                          makeLockedHereNote(LocLocked, Kind));
+  }
+
+  void handleDoubleLock(StringRef Kind, Name LockName, SourceLocation LocLocked,
+                        SourceLocation LocDoubleLock) override {
+    if (LocDoubleLock.isInvalid())
+      LocDoubleLock = FunLocation;
+    PartialDiagnosticAt Warning(LocDoubleLock, S.PDiag(diag::warn_double_lock)
+                                                   << Kind << LockName);
+    Warnings.emplace_back(std::move(Warning),
+                          makeLockedHereNote(LocLocked, Kind));
+  }
+
+  void handleMutexHeldEndOfScope(StringRef Kind, Name LockName,
+                                 SourceLocation LocLocked,
+                                 SourceLocation LocEndOfScope,
+                                 LockErrorKind LEK) override {
+    unsigned DiagID = 0;
+    switch (LEK) {
+      case LEK_LockedSomePredecessors:
+        DiagID = diag::warn_lock_some_predecessors;
+        break;
+      case LEK_LockedSomeLoopIterations:
+        DiagID = diag::warn_expecting_lock_held_on_loop;
+        break;
+      case LEK_LockedAtEndOfFunction:
+        DiagID = diag::warn_no_unlock;
+        break;
+      case LEK_NotLockedAtEndOfFunction:
+        DiagID = diag::warn_expecting_locked;
+        break;
+    }
+    if (LocEndOfScope.isInvalid())
+      LocEndOfScope = FunEndLocation;
+
+    PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << Kind
+                                                               << LockName);
+    Warnings.emplace_back(std::move(Warning),
+                          makeLockedHereNote(LocLocked, Kind));
+  }
+
+  void handleExclusiveAndShared(StringRef Kind, Name LockName,
+                                SourceLocation Loc1,
+                                SourceLocation Loc2) override {
+    PartialDiagnosticAt Warning(Loc1,
+                                S.PDiag(diag::warn_lock_exclusive_and_shared)
+                                    << Kind << LockName);
+    PartialDiagnosticAt Note(Loc2, S.PDiag(diag::note_lock_exclusive_and_shared)
+                                       << Kind << LockName);
+    Warnings.emplace_back(std::move(Warning), getNotes(Note));
+  }
+
+  void handleNoMutexHeld(const NamedDecl *D, ProtectedOperationKind POK,
+                         AccessKind AK, SourceLocation Loc) override {
+    assert((POK == POK_VarAccess || POK == POK_VarDereference) &&
+           "Only works for variables");
+    unsigned DiagID = POK == POK_VarAccess?
+                        diag::warn_variable_requires_any_lock:
+                        diag::warn_var_deref_requires_any_lock;
+    PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
+      << D << getLockKindFromAccessKind(AK));
+    Warnings.emplace_back(std::move(Warning), getNotes());
+  }
+
+  void handleMutexNotHeld(StringRef Kind, const NamedDecl *D,
+                          ProtectedOperationKind POK, Name LockName,
+                          LockKind LK, SourceLocation Loc,
+                          Name *PossibleMatch) override {
+    unsigned DiagID = 0;
+    if (PossibleMatch) {
+      switch (POK) {
+        case POK_VarAccess:
+          DiagID = diag::warn_variable_requires_lock_precise;
+          break;
+        case POK_VarDereference:
+          DiagID = diag::warn_var_deref_requires_lock_precise;
+          break;
+        case POK_FunctionCall:
+          DiagID = diag::warn_fun_requires_lock_precise;
+          break;
+        case POK_PassByRef:
+          DiagID = diag::warn_guarded_pass_by_reference;
+          break;
+        case POK_PtPassByRef:
+          DiagID = diag::warn_pt_guarded_pass_by_reference;
+          break;
+      }
+      PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
+                                                       << D
+                                                       << LockName << LK);
+      PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
+                                        << *PossibleMatch);
+      if (Verbose && POK == POK_VarAccess) {
+        PartialDiagnosticAt VNote(D->getLocation(),
+                                  S.PDiag(diag::note_guarded_by_declared_here)
+                                      << D->getDeclName());
+        Warnings.emplace_back(std::move(Warning), getNotes(Note, VNote));
+      } else
+        Warnings.emplace_back(std::move(Warning), getNotes(Note));
+    } else {
+      switch (POK) {
+        case POK_VarAccess:
+          DiagID = diag::warn_variable_requires_lock;
+          break;
+        case POK_VarDereference:
+          DiagID = diag::warn_var_deref_requires_lock;
+          break;
+        case POK_FunctionCall:
+          DiagID = diag::warn_fun_requires_lock;
+          break;
+        case POK_PassByRef:
+          DiagID = diag::warn_guarded_pass_by_reference;
+          break;
+        case POK_PtPassByRef:
+          DiagID = diag::warn_pt_guarded_pass_by_reference;
+          break;
+      }
+      PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
+                                                       << D
+                                                       << LockName << LK);
+      if (Verbose && POK == POK_VarAccess) {
+        PartialDiagnosticAt Note(D->getLocation(),
+                                 S.PDiag(diag::note_guarded_by_declared_here));
+        Warnings.emplace_back(std::move(Warning), getNotes(Note));
+      } else
+        Warnings.emplace_back(std::move(Warning), getNotes());
+    }
+  }
+
+  void handleNegativeNotHeld(StringRef Kind, Name LockName, Name Neg,
+                             SourceLocation Loc) override {
+    PartialDiagnosticAt Warning(Loc,
+        S.PDiag(diag::warn_acquire_requires_negative_cap)
+        << Kind << LockName << Neg);
+    Warnings.emplace_back(std::move(Warning), getNotes());
+  }
+
+  void handleNegativeNotHeld(const NamedDecl *D, Name LockName,
+                             SourceLocation Loc) override {
+    PartialDiagnosticAt Warning(
+        Loc, S.PDiag(diag::warn_fun_requires_negative_cap) << D << LockName);
+    Warnings.emplace_back(std::move(Warning), getNotes());
+  }
+
+  void handleFunExcludesLock(StringRef Kind, Name FunName, Name LockName,
+                             SourceLocation Loc) override {
+    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_fun_excludes_mutex)
+                                         << Kind << FunName << LockName);
+    Warnings.emplace_back(std::move(Warning), getNotes());
+  }
+
+  void handleLockAcquiredBefore(StringRef Kind, Name L1Name, Name L2Name,
+                                SourceLocation Loc) override {
+    PartialDiagnosticAt Warning(Loc,
+      S.PDiag(diag::warn_acquired_before) << Kind << L1Name << L2Name);
+    Warnings.emplace_back(std::move(Warning), getNotes());
+  }
+
+  void handleBeforeAfterCycle(Name L1Name, SourceLocation Loc) override {
+    PartialDiagnosticAt Warning(Loc,
+      S.PDiag(diag::warn_acquired_before_after_cycle) << L1Name);
+    Warnings.emplace_back(std::move(Warning), getNotes());
+  }
+
+  void enterFunction(const FunctionDecl* FD) override {
+    CurrentFunction = FD;
+  }
+
+  void leaveFunction(const FunctionDecl* FD) override {
+    CurrentFunction = nullptr;
+  }
+};
+} // anonymous namespace
+} // namespace threadSafety
+} // namespace clang
+
+//===----------------------------------------------------------------------===//
+// -Wconsumed
+//===----------------------------------------------------------------------===//
+
+namespace clang {
+namespace consumed {
+namespace {
+class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
+
+  Sema &S;
+  DiagList Warnings;
+
+public:
+
+  ConsumedWarningsHandler(Sema &S) : S(S) {}
+
+  void emitDiagnostics() override {
+    Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
+    for (const auto &Diag : Warnings) {
+      S.Diag(Diag.first.first, Diag.first.second);
+      for (const auto &Note : Diag.second)
+        S.Diag(Note.first, Note.second);
+    }
+  }
+
+  void warnLoopStateMismatch(SourceLocation Loc,
+                             StringRef VariableName) override {
+    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_loop_state_mismatch) <<
+      VariableName);
+
+    Warnings.emplace_back(std::move(Warning), OptionalNotes());
+  }
+
+  void warnParamReturnTypestateMismatch(SourceLocation Loc,
+                                        StringRef VariableName,
+                                        StringRef ExpectedState,
+                                        StringRef ObservedState) override {
+
+    PartialDiagnosticAt Warning(Loc, S.PDiag(
+      diag::warn_param_return_typestate_mismatch) << VariableName <<
+        ExpectedState << ObservedState);
+
+    Warnings.emplace_back(std::move(Warning), OptionalNotes());
+  }
+
+  void warnParamTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
+                                  StringRef ObservedState) override {
+
+    PartialDiagnosticAt Warning(Loc, S.PDiag(
+      diag::warn_param_typestate_mismatch) << ExpectedState << ObservedState);
+
+    Warnings.emplace_back(std::move(Warning), OptionalNotes());
+  }
+
+  void warnReturnTypestateForUnconsumableType(SourceLocation Loc,
+                                              StringRef TypeName) override {
+    PartialDiagnosticAt Warning(Loc, S.PDiag(
+      diag::warn_return_typestate_for_unconsumable_type) << TypeName);
+
+    Warnings.emplace_back(std::move(Warning), OptionalNotes());
+  }
+
+  void warnReturnTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
+                                   StringRef ObservedState) override {
+
+    PartialDiagnosticAt Warning(Loc, S.PDiag(
+      diag::warn_return_typestate_mismatch) << ExpectedState << ObservedState);
+
+    Warnings.emplace_back(std::move(Warning), OptionalNotes());
+  }
+
+  void warnUseOfTempInInvalidState(StringRef MethodName, StringRef State,
+                                   SourceLocation Loc) override {
+
+    PartialDiagnosticAt Warning(Loc, S.PDiag(
+      diag::warn_use_of_temp_in_invalid_state) << MethodName << State);
+
+    Warnings.emplace_back(std::move(Warning), OptionalNotes());
+  }
+
+  void warnUseInInvalidState(StringRef MethodName, StringRef VariableName,
+                             StringRef State, SourceLocation Loc) override {
+
+    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_in_invalid_state) <<
+                                MethodName << VariableName << State);
+
+    Warnings.emplace_back(std::move(Warning), OptionalNotes());
+  }
+};
+} // anonymous namespace
+} // namespace consumed
+} // namespace clang
+
+//===----------------------------------------------------------------------===//
+// Unsafe buffer usage analysis.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class UnsafeBufferUsageReporter : public UnsafeBufferUsageHandler {
+  Sema &S;
+
+public:
+  UnsafeBufferUsageReporter(Sema &S) : S(S) {}
+
+  void handleUnsafeOperation(const Stmt *Operation,
+                             bool IsRelatedToDecl) override {
+    SourceLocation Loc;
+    SourceRange Range;
+    unsigned MsgParam = 0;
+    if (const auto *ASE = dyn_cast<ArraySubscriptExpr>(Operation)) {
+      Loc = ASE->getBase()->getExprLoc();
+      Range = ASE->getBase()->getSourceRange();
+      MsgParam = 2;
+    } else if (const auto *BO = dyn_cast<BinaryOperator>(Operation)) {
+      BinaryOperator::Opcode Op = BO->getOpcode();
+      if (Op == BO_Add || Op == BO_AddAssign || Op == BO_Sub ||
+          Op == BO_SubAssign) {
+        if (BO->getRHS()->getType()->isIntegerType()) {
+          Loc = BO->getLHS()->getExprLoc();
+          Range = BO->getLHS()->getSourceRange();
+        } else {
+          Loc = BO->getRHS()->getExprLoc();
+          Range = BO->getRHS()->getSourceRange();
+        }
+        MsgParam = 1;
+      }
+    } else if (const auto *UO = dyn_cast<UnaryOperator>(Operation)) {
+      UnaryOperator::Opcode Op = UO->getOpcode();
+      if (Op == UO_PreInc || Op == UO_PreDec || Op == UO_PostInc ||
+          Op == UO_PostDec) {
+        Loc = UO->getSubExpr()->getExprLoc();
+        Range = UO->getSubExpr()->getSourceRange();
+        MsgParam = 1;
+      }
+    } else {
+      Loc = Operation->getBeginLoc();
+      Range = Operation->getSourceRange();
+    }
+    if (IsRelatedToDecl)
+      S.Diag(Loc, diag::note_unsafe_buffer_operation) << MsgParam << Range;
+    else
+      S.Diag(Loc, diag::warn_unsafe_buffer_operation) << MsgParam << Range;
+  }
+
+  // FIXME: rename to handleUnsafeVariable
+  void handleFixableVariable(const VarDecl *Variable,
+                             FixItList &&Fixes) override {
+    const auto &D =
+        S.Diag(Variable->getLocation(), diag::warn_unsafe_buffer_variable);
+    D << Variable;
+    D << (Variable->getType()->isPointerType() ? 0 : 1);
+    D << Variable->getSourceRange();
+    for (const auto &F : Fixes)
+      D << F;
+  }
+};
+} // namespace
+
+//===----------------------------------------------------------------------===//
+// AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
+//  warnings on a function, method, or block.
+//===----------------------------------------------------------------------===//
+
+sema::AnalysisBasedWarnings::Policy::Policy() {
+  enableCheckFallThrough = 1;
+  enableCheckUnreachable = 0;
+  enableThreadSafetyAnalysis = 0;
+  enableConsumedAnalysis = 0;
+}
+
+/// InterProceduralData aims to be a storage of whatever data should be passed
+/// between analyses of different functions.
+///
+/// At the moment, its primary goal is to make the information gathered during
+/// the analysis of the blocks available during the analysis of the enclosing
+/// function.  This is important due to the fact that blocks are analyzed before
+/// the enclosed function is even parsed fully, so it is not viable to access
+/// anything in the outer scope while analyzing the block.  On the other hand,
+/// re-building CFG for blocks and re-analyzing them when we do have all the
+/// information (i.e. during the analysis of the enclosing function) seems to be
+/// ill-designed.
+class sema::AnalysisBasedWarnings::InterProceduralData {
+public:
+  // It is important to analyze blocks within functions because it's a very
+  // common pattern to capture completion handler parameters by blocks.
+  CalledOnceInterProceduralData CalledOnceData;
+};
+
+static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag) {
+  return (unsigned)!D.isIgnored(diag, SourceLocation());
+}
+
+sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s)
+    : S(s), IPData(std::make_unique<InterProceduralData>()),
+      NumFunctionsAnalyzed(0), NumFunctionsWithBadCFGs(0), NumCFGBlocks(0),
+      MaxCFGBlocksPerFunction(0), NumUninitAnalysisFunctions(0),
+      NumUninitAnalysisVariables(0), MaxUninitAnalysisVariablesPerFunction(0),
+      NumUninitAnalysisBlockVisits(0),
+      MaxUninitAnalysisBlockVisitsPerFunction(0) {
+
+  using namespace diag;
+  DiagnosticsEngine &D = S.getDiagnostics();
+
+  DefaultPolicy.enableCheckUnreachable =
+      isEnabled(D, warn_unreachable) || isEnabled(D, warn_unreachable_break) ||
+      isEnabled(D, warn_unreachable_return) ||
+      isEnabled(D, warn_unreachable_loop_increment);
+
+  DefaultPolicy.enableThreadSafetyAnalysis = isEnabled(D, warn_double_lock);
+
+  DefaultPolicy.enableConsumedAnalysis =
+      isEnabled(D, warn_use_in_invalid_state);
+}
+
+// We need this here for unique_ptr with forward declared class.
+sema::AnalysisBasedWarnings::~AnalysisBasedWarnings() = default;
+
+static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) {
+  for (const auto &D : fscope->PossiblyUnreachableDiags)
+    S.Diag(D.Loc, D.PD);
+}
+
+void clang::sema::AnalysisBasedWarnings::IssueWarnings(
+    sema::AnalysisBasedWarnings::Policy P, sema::FunctionScopeInfo *fscope,
+    const Decl *D, QualType BlockType) {
+
+  // We avoid doing analysis-based warnings when there are errors for
+  // two reasons:
+  // (1) The CFGs often can't be constructed (if the body is invalid), so
+  //     don't bother trying.
+  // (2) The code already has problems; running the analysis just takes more
+  //     time.
+  DiagnosticsEngine &Diags = S.getDiagnostics();
+
+  // Do not do any analysis if we are going to just ignore them.
+  if (Diags.getIgnoreAllWarnings() ||
+      (Diags.getSuppressSystemWarnings() &&
+       S.SourceMgr.isInSystemHeader(D->getLocation())))
+    return;
+
+  // For code in dependent contexts, we'll do this at instantiation time.
+  if (cast<DeclContext>(D)->isDependentContext())
+    return;
+
+  if (S.hasUncompilableErrorOccurred()) {
+    // Flush out any possibly unreachable diagnostics.
+    flushDiagnostics(S, fscope);
+    return;
+  }
+
+  const Stmt *Body = D->getBody();
+  assert(Body);
+
+  // Construct the analysis context with the specified CFG build options.
+  AnalysisDeclContext AC(/* AnalysisDeclContextManager */ nullptr, D);
+
+  // Don't generate EH edges for CallExprs as we'd like to avoid the n^2
+  // explosion for destructors that can result and the compile time hit.
+  AC.getCFGBuildOptions().PruneTriviallyFalseEdges = true;
+  AC.getCFGBuildOptions().AddEHEdges = false;
+  AC.getCFGBuildOptions().AddInitializers = true;
+  AC.getCFGBuildOptions().AddImplicitDtors = true;
+  AC.getCFGBuildOptions().AddTemporaryDtors = true;
+  AC.getCFGBuildOptions().AddCXXNewAllocator = false;
+  AC.getCFGBuildOptions().AddCXXDefaultInitExprInCtors = true;
+
+  // Force that certain expressions appear as CFGElements in the CFG.  This
+  // is used to speed up various analyses.
+  // FIXME: This isn't the right factoring.  This is here for initial
+  // prototyping, but we need a way for analyses to say what expressions they
+  // expect to always be CFGElements and then fill in the BuildOptions
+  // appropriately.  This is essentially a layering violation.
+  if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis ||
+      P.enableConsumedAnalysis) {
+    // Unreachable code analysis and thread safety require a linearized CFG.
+    AC.getCFGBuildOptions().setAllAlwaysAdd();
+  }
+  else {
+    AC.getCFGBuildOptions()
+      .setAlwaysAdd(Stmt::BinaryOperatorClass)
+      .setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
+      .setAlwaysAdd(Stmt::BlockExprClass)
+      .setAlwaysAdd(Stmt::CStyleCastExprClass)
+      .setAlwaysAdd(Stmt::DeclRefExprClass)
+      .setAlwaysAdd(Stmt::ImplicitCastExprClass)
+      .setAlwaysAdd(Stmt::UnaryOperatorClass);
+  }
+
+  // Install the logical handler.
+  std::optional<LogicalErrorHandler> LEH;
+  if (LogicalErrorHandler::hasActiveDiagnostics(Diags, D->getBeginLoc())) {
+    LEH.emplace(S);
+    AC.getCFGBuildOptions().Observer = &*LEH;
+  }
+
+  // Emit delayed diagnostics.
+  if (!fscope->PossiblyUnreachableDiags.empty()) {
+    bool analyzed = false;
+
+    // Register the expressions with the CFGBuilder.
+    for (const auto &D : fscope->PossiblyUnreachableDiags) {
+      for (const Stmt *S : D.Stmts)
+        AC.registerForcedBlockExpression(S);
+    }
+
+    if (AC.getCFG()) {
+      analyzed = true;
+      for (const auto &D : fscope->PossiblyUnreachableDiags) {
+        bool AllReachable = true;
+        for (const Stmt *S : D.Stmts) {
+          const CFGBlock *block = AC.getBlockForRegisteredExpression(S);
+          CFGReverseBlockReachabilityAnalysis *cra =
+              AC.getCFGReachablityAnalysis();
+          // FIXME: We should be able to assert that block is non-null, but
+          // the CFG analysis can skip potentially-evaluated expressions in
+          // edge cases; see test/Sema/vla-2.c.
+          if (block && cra) {
+            // Can this block be reached from the entrance?
+            if (!cra->isReachable(&AC.getCFG()->getEntry(), block)) {
+              AllReachable = false;
+              break;
+            }
+          }
+          // If we cannot map to a basic block, assume the statement is
+          // reachable.
+        }
+
+        if (AllReachable)
+          S.Diag(D.Loc, D.PD);
+      }
+    }
+
+    if (!analyzed)
+      flushDiagnostics(S, fscope);
+  }
+
+  // Warning: check missing 'return'
+  if (P.enableCheckFallThrough) {
+    const CheckFallThroughDiagnostics &CD =
+        (isa<BlockDecl>(D)
+             ? CheckFallThroughDiagnostics::MakeForBlock()
+             : (isa<CXXMethodDecl>(D) &&
+                cast<CXXMethodDecl>(D)->getOverloadedOperator() == OO_Call &&
+                cast<CXXMethodDecl>(D)->getParent()->isLambda())
+                   ? CheckFallThroughDiagnostics::MakeForLambda()
+                   : (fscope->isCoroutine()
+                          ? CheckFallThroughDiagnostics::MakeForCoroutine(D)
+                          : CheckFallThroughDiagnostics::MakeForFunction(D)));
+    CheckFallThroughForBody(S, D, Body, BlockType, CD, AC, fscope);
+  }
+
+  // Warning: check for unreachable code
+  if (P.enableCheckUnreachable) {
+    // Only check for unreachable code on non-template instantiations.
+    // Different template instantiations can effectively change the control-flow
+    // and it is very difficult to prove that a snippet of code in a template
+    // is unreachable for all instantiations.
+    bool isTemplateInstantiation = false;
+    if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
+      isTemplateInstantiation = Function->isTemplateInstantiation();
+    if (!isTemplateInstantiation)
+      CheckUnreachable(S, AC);
+  }
+
+  // Check for thread safety violations
+  if (P.enableThreadSafetyAnalysis) {
+    SourceLocation FL = AC.getDecl()->getLocation();
+    SourceLocation FEL = AC.getDecl()->getEndLoc();
+    threadSafety::ThreadSafetyReporter Reporter(S, FL, FEL);
+    if (!Diags.isIgnored(diag::warn_thread_safety_beta, D->getBeginLoc()))
+      Reporter.setIssueBetaWarnings(true);
+    if (!Diags.isIgnored(diag::warn_thread_safety_verbose, D->getBeginLoc()))
+      Reporter.setVerbose(true);
+
+    threadSafety::runThreadSafetyAnalysis(AC, Reporter,
+                                          &S.ThreadSafetyDeclCache);
+    Reporter.emitDiagnostics();
+  }
+
+  // Check for violations of consumed properties.
+  if (P.enableConsumedAnalysis) {
+    consumed::ConsumedWarningsHandler WarningHandler(S);
+    consumed::ConsumedAnalyzer Analyzer(WarningHandler);
+    Analyzer.run(AC);
+  }
+
+  if (!Diags.isIgnored(diag::warn_uninit_var, D->getBeginLoc()) ||
+      !Diags.isIgnored(diag::warn_sometimes_uninit_var, D->getBeginLoc()) ||
+      !Diags.isIgnored(diag::warn_maybe_uninit_var, D->getBeginLoc()) ||
+      !Diags.isIgnored(diag::warn_uninit_const_reference, D->getBeginLoc())) {
+    if (CFG *cfg = AC.getCFG()) {
+      UninitValsDiagReporter reporter(S);
+      UninitVariablesAnalysisStats stats;
+      std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats));
+      runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC,
+                                        reporter, stats);
+
+      if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
+        ++NumUninitAnalysisFunctions;
+        NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
+        NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
+        MaxUninitAnalysisVariablesPerFunction =
+            std::max(MaxUninitAnalysisVariablesPerFunction,
+                     stats.NumVariablesAnalyzed);
+        MaxUninitAnalysisBlockVisitsPerFunction =
+            std::max(MaxUninitAnalysisBlockVisitsPerFunction,
+                     stats.NumBlockVisits);
+      }
+    }
+  }
+
+  // Check for violations of "called once" parameter properties.
+  if (S.getLangOpts().ObjC && !S.getLangOpts().CPlusPlus &&
+      shouldAnalyzeCalledOnceParameters(Diags, D->getBeginLoc())) {
+    if (AC.getCFG()) {
+      CalledOnceCheckReporter Reporter(S, IPData->CalledOnceData);
+      checkCalledOnceParameters(
+          AC, Reporter,
+          shouldAnalyzeCalledOnceConventions(Diags, D->getBeginLoc()));
+    }
+  }
+
+  bool FallThroughDiagFull =
+      !Diags.isIgnored(diag::warn_unannotated_fallthrough, D->getBeginLoc());
+  bool FallThroughDiagPerFunction = !Diags.isIgnored(
+      diag::warn_unannotated_fallthrough_per_function, D->getBeginLoc());
+  if (FallThroughDiagFull || FallThroughDiagPerFunction ||
+      fscope->HasFallthroughStmt) {
+    DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
+  }
+
+  if (S.getLangOpts().ObjCWeak &&
+      !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, D->getBeginLoc()))
+    diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
+
+
+  // Check for infinite self-recursion in functions
+  if (!Diags.isIgnored(diag::warn_infinite_recursive_function,
+                       D->getBeginLoc())) {
+    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+      checkRecursiveFunction(S, FD, Body, AC);
+    }
+  }
+
+  // Check for throw out of non-throwing function.
+  if (!Diags.isIgnored(diag::warn_throw_in_noexcept_func, D->getBeginLoc()))
+    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
+      if (S.getLangOpts().CPlusPlus && isNoexcept(FD))
+        checkThrowInNonThrowingFunc(S, FD, AC);
+
+  // Emit unsafe buffer usage warnings and fixits.
+  if (!Diags.isIgnored(diag::warn_unsafe_buffer_operation, D->getBeginLoc()) ||
+      !Diags.isIgnored(diag::warn_unsafe_buffer_variable, D->getBeginLoc())) {
+    UnsafeBufferUsageReporter R(S);
+    checkUnsafeBufferUsage(D, R);
+  }
+
+  // If none of the previous checks caused a CFG build, trigger one here
+  // for the logical error handler.
+  if (LogicalErrorHandler::hasActiveDiagnostics(Diags, D->getBeginLoc())) {
+    AC.getCFG();
+  }
+
+  // Collect statistics about the CFG if it was built.
+  if (S.CollectStats && AC.isCFGBuilt()) {
+    ++NumFunctionsAnalyzed;
+    if (CFG *cfg = AC.getCFG()) {
+      // If we successfully built a CFG for this context, record some more
+      // detail information about it.
+      NumCFGBlocks += cfg->getNumBlockIDs();
+      MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction,
+                                         cfg->getNumBlockIDs());
+    } else {
+      ++NumFunctionsWithBadCFGs;
+    }
+  }
+}
+
+void clang::sema::AnalysisBasedWarnings::PrintStats() const {
+  llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
+
+  unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
+  unsigned AvgCFGBlocksPerFunction =
+      !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
+  llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
+               << NumFunctionsWithBadCFGs << " w/o CFGs).\n"
+               << "  " << NumCFGBlocks << " CFG blocks built.\n"
+               << "  " << AvgCFGBlocksPerFunction
+               << " average CFG blocks per function.\n"
+               << "  " << MaxCFGBlocksPerFunction
+               << " max CFG blocks per function.\n";
+
+  unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
+      : NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
+  unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
+      : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
+  llvm::errs() << NumUninitAnalysisFunctions
+               << " functions analyzed for uninitialiazed variables\n"
+               << "  " << NumUninitAnalysisVariables << " variables analyzed.\n"
+               << "  " << AvgUninitVariablesPerFunction
+               << " average variables per function.\n"
+               << "  " << MaxUninitAnalysisVariablesPerFunction
+               << " max variables per function.\n"
+               << "  " << NumUninitAnalysisBlockVisits << " block visits.\n"
+               << "  " << AvgUninitBlockVisitsPerFunction
+               << " average block visits per function.\n"
+               << "  " << MaxUninitAnalysisBlockVisitsPerFunction
+               << " max block visits per function.\n";
+}