Export clang-format16 via ydblib project

6e6be3a95868fde888d801b7590af4044049563f

1 files changed, 171 insertions, 0 deletions

diff --git a/contrib/libs/clang16/tools/extra/clang-tidy/misc/ThrowByValueCatchByReferenceCheck.cpp b/contrib/libs/clang16/tools/extra/clang-tidy/misc/ThrowByValueCatchByReferenceCheck.cpp
new file mode 100644
index 0000000000..abe7bed9df
--- /dev/null
+++ b/contrib/libs/clang16/tools/extra/clang-tidy/misc/ThrowByValueCatchByReferenceCheck.cpp
@@ -0,0 +1,171 @@
+//===--- ThrowByValueCatchByReferenceCheck.cpp - clang-tidy----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "ThrowByValueCatchByReferenceCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/OperationKinds.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::misc {
+
+ThrowByValueCatchByReferenceCheck::ThrowByValueCatchByReferenceCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      CheckAnonymousTemporaries(Options.get("CheckThrowTemporaries", true)),
+      WarnOnLargeObject(Options.get("WarnOnLargeObject", false)),
+      // Cannot access `ASTContext` from here so set it to an extremal value.
+      MaxSizeOptions(
+          Options.get("MaxSize", std::numeric_limits<uint64_t>::max())),
+      MaxSize(MaxSizeOptions) {}
+
+void ThrowByValueCatchByReferenceCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(cxxThrowExpr().bind("throw"), this);
+  Finder->addMatcher(cxxCatchStmt().bind("catch"), this);
+}
+
+void ThrowByValueCatchByReferenceCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "CheckThrowTemporaries", true);
+  Options.store(Opts, "WarnOnLargeObjects", WarnOnLargeObject);
+  Options.store(Opts, "MaxSize", MaxSizeOptions);
+}
+
+void ThrowByValueCatchByReferenceCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  diagnoseThrowLocations(Result.Nodes.getNodeAs<CXXThrowExpr>("throw"));
+  diagnoseCatchLocations(Result.Nodes.getNodeAs<CXXCatchStmt>("catch"),
+                         *Result.Context);
+}
+
+bool ThrowByValueCatchByReferenceCheck::isFunctionParameter(
+    const DeclRefExpr *DeclRefExpr) {
+  return isa<ParmVarDecl>(DeclRefExpr->getDecl());
+}
+
+bool ThrowByValueCatchByReferenceCheck::isCatchVariable(
+    const DeclRefExpr *DeclRefExpr) {
+  auto *ValueDecl = DeclRefExpr->getDecl();
+  if (auto *VarDecl = dyn_cast<clang::VarDecl>(ValueDecl))
+    return VarDecl->isExceptionVariable();
+  return false;
+}
+
+bool ThrowByValueCatchByReferenceCheck::isFunctionOrCatchVar(
+    const DeclRefExpr *DeclRefExpr) {
+  return isFunctionParameter(DeclRefExpr) || isCatchVariable(DeclRefExpr);
+}
+
+void ThrowByValueCatchByReferenceCheck::diagnoseThrowLocations(
+    const CXXThrowExpr *ThrowExpr) {
+  if (!ThrowExpr)
+    return;
+  auto *SubExpr = ThrowExpr->getSubExpr();
+  if (!SubExpr)
+    return;
+  auto QualType = SubExpr->getType();
+  if (QualType->isPointerType()) {
+    // The code is throwing a pointer.
+    // In case it is string literal, it is safe and we return.
+    auto *Inner = SubExpr->IgnoreParenImpCasts();
+    if (isa<StringLiteral>(Inner))
+      return;
+    // If it's a variable from a catch statement, we return as well.
+    auto *DeclRef = dyn_cast<DeclRefExpr>(Inner);
+    if (DeclRef && isCatchVariable(DeclRef)) {
+      return;
+    }
+    diag(SubExpr->getBeginLoc(), "throw expression throws a pointer; it should "
+                                 "throw a non-pointer value instead");
+  }
+  // If the throw statement does not throw by pointer then it throws by value
+  // which is ok.
+  // There are addition checks that emit diagnosis messages if the thrown value
+  // is not an RValue. See:
+  // https://www.securecoding.cert.org/confluence/display/cplusplus/ERR09-CPP.+Throw+anonymous+temporaries
+  // This behavior can be influenced by an option.
+
+  // If we encounter a CXXThrowExpr, we move through all casts until you either
+  // encounter a DeclRefExpr or a CXXConstructExpr.
+  // If it's a DeclRefExpr, we emit a message if the referenced variable is not
+  // a catch variable or function parameter.
+  // When encountering a CopyOrMoveConstructor: emit message if after casts,
+  // the expression is a LValue
+  if (CheckAnonymousTemporaries) {
+    bool Emit = false;
+    auto *CurrentSubExpr = SubExpr->IgnoreImpCasts();
+    const auto *VariableReference = dyn_cast<DeclRefExpr>(CurrentSubExpr);
+    const auto *ConstructorCall = dyn_cast<CXXConstructExpr>(CurrentSubExpr);
+    // If we have a DeclRefExpr, we flag for emitting a diagnosis message in
+    // case the referenced variable is neither a function parameter nor a
+    // variable declared in the catch statement.
+    if (VariableReference)
+      Emit = !isFunctionOrCatchVar(VariableReference);
+    else if (ConstructorCall &&
+             ConstructorCall->getConstructor()->isCopyOrMoveConstructor()) {
+      // If we have a copy / move construction, we emit a diagnosis message if
+      // the object that we copy construct from is neither a function parameter
+      // nor a variable declared in a catch statement
+      auto ArgIter =
+          ConstructorCall
+              ->arg_begin(); // there's only one for copy constructors
+      auto *CurrentSubExpr = (*ArgIter)->IgnoreImpCasts();
+      if (CurrentSubExpr->isLValue()) {
+        if (auto *Tmp = dyn_cast<DeclRefExpr>(CurrentSubExpr))
+          Emit = !isFunctionOrCatchVar(Tmp);
+        else if (isa<CallExpr>(CurrentSubExpr))
+          Emit = true;
+      }
+    }
+    if (Emit)
+      diag(SubExpr->getBeginLoc(),
+           "throw expression should throw anonymous temporary values instead");
+  }
+}
+
+void ThrowByValueCatchByReferenceCheck::diagnoseCatchLocations(
+    const CXXCatchStmt *CatchStmt, ASTContext &Context) {
+  if (!CatchStmt)
+    return;
+  auto CaughtType = CatchStmt->getCaughtType();
+  if (CaughtType.isNull())
+    return;
+  auto *VarDecl = CatchStmt->getExceptionDecl();
+  if (const auto *PT = CaughtType.getCanonicalType()->getAs<PointerType>()) {
+    const char *DiagMsgCatchReference =
+        "catch handler catches a pointer value; "
+        "should throw a non-pointer value and "
+        "catch by reference instead";
+    // We do not diagnose when catching pointer to strings since we also allow
+    // throwing string literals.
+    if (!PT->getPointeeType()->isAnyCharacterType())
+      diag(VarDecl->getBeginLoc(), DiagMsgCatchReference);
+  } else if (!CaughtType->isReferenceType()) {
+    const char *DiagMsgCatchReference = "catch handler catches by value; "
+                                        "should catch by reference instead";
+    // If it's not a pointer and not a reference then it must be caught "by
+    // value". In this case we should emit a diagnosis message unless the type
+    // is trivial.
+    if (!CaughtType.isTrivialType(Context)) {
+      diag(VarDecl->getBeginLoc(), DiagMsgCatchReference);
+    } else if (WarnOnLargeObject) {
+      // If the type is trivial, then catching it by reference is not dangerous.
+      // However, catching large objects by value decreases the performance.
+
+      // We can now access `ASTContext` so if `MaxSize` is an extremal value
+      // then set it to the size of `size_t`.
+      if (MaxSize == std::numeric_limits<uint64_t>::max())
+        MaxSize = Context.getTypeSize(Context.getSizeType());
+      if (Context.getTypeSize(CaughtType) > MaxSize)
+        diag(VarDecl->getBeginLoc(), DiagMsgCatchReference);
+    }
+  }
+}
+
+} // namespace clang::tidy::misc