Sync to LLVM xf672b6170ce

clang-tools-extra/CMakeLists.txt

@@ -1,3 +1,5 @@
+include(CMakeDependentOption)
+
 add_subdirectory(clang-apply-replacements)
 add_subdirectory(clang-reorder-fields)
 add_subdirectory(modularize)
@@ -9,7 +11,6 @@ add_subdirectory(clang-doc)
 add_subdirectory(clang-include-fixer)
 add_subdirectory(clang-move)
 add_subdirectory(clang-query)
-add_subdirectory(clangd)
 add_subdirectory(pp-trace)
 add_subdirectory(tool-template)
 
@@ -25,3 +26,9 @@ if( CLANG_TOOLS_EXTRA_INCLUDE_DOCS )
   add_subdirectory(docs)
 endif()
 
+# clangd has its own CMake tree. It requires threads.
+CMAKE_DEPENDENT_OPTION(CLANG_ENABLE_CLANGD "Build clangd language server" ON
+                       "LLVM_ENABLE_THREADS" OFF)
+if (CLANG_ENABLE_CLANGD)
+  add_subdirectory(clangd)
+endif()

clang-tools-extra/clang-tidy/add_new_check.py

@@ -46,7 +46,7 @@ def adapt_cmake(module_path, check_name_camel):
 
 
 # Adds a header for the new check.
-def write_header(module_path, module, check_name, check_name_camel):
+def write_header(module_path, module, namespace, check_name, check_name_camel):
   check_name_dashes = module + '-' + check_name
   filename = os.path.join(module_path, check_name_camel) + '.h'
   print('Creating %s...' % filename)
@@ -73,7 +73,7 @@ def write_header(module_path, module, check_name, check_name_camel):
 
 namespace clang {
 namespace tidy {
-namespace %(module)s {
+namespace %(namespace)s {
 
 /// FIXME: Write a short description.
 ///
@@ -87,19 +87,20 @@ class %(check_name)s : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 };
 
-} // namespace %(module)s
+} // namespace %(namespace)s
 } // namespace tidy
 } // namespace clang
 
 #endif // %(header_guard)s
 """ % {'header_guard': header_guard,
        'check_name': check_name_camel,
        'check_name_dashes': check_name_dashes,
-       'module': module})
+       'module': module,
+       'namespace': namespace})
 
 
 # Adds the implementation of the new check.
-def write_implementation(module_path, module, check_name_camel):
+def write_implementation(module_path, module, namespace, check_name_camel):
   filename = os.path.join(module_path, check_name_camel) + '.cpp'
   print('Creating %s...' % filename)
   with open(filename, 'w') as f:
@@ -124,7 +125,7 @@ def write_implementation(module_path, module, check_name_camel):
 
 namespace clang {
 namespace tidy {
-namespace %(module)s {
+namespace %(namespace)s {
 
 void %(check_name)s::registerMatchers(MatchFinder *Finder) {
   // FIXME: Add matchers.
@@ -142,11 +143,12 @@ def write_implementation(module_path, module, check_name_camel):
       << FixItHint::CreateInsertion(MatchedDecl->getLocation(), "awesome_");
 }
 
-} // namespace %(module)s
+} // namespace %(namespace)s
 } // namespace tidy
 } // namespace clang
 """ % {'check_name': check_name_camel,
-       'module': module})
+       'module': module,
+       'namespace': namespace})
 
 
 # Modifies the module to include the new check.
@@ -375,8 +377,15 @@ def main():
 
   if not adapt_cmake(module_path, check_name_camel):
     return
-  write_header(module_path, module, check_name, check_name_camel)
-  write_implementation(module_path, module, check_name_camel)
+
+  # Map module names to namespace names that don't conflict with widely used top-level namespaces.
+  if module == 'llvm':
+    namespace = module + '_check'
+  else:
+    namespace = module
+
+  write_header(module_path, module, namespace, check_name, check_name_camel)
+  write_implementation(module_path, module, namespace, check_name_camel)
   adapt_module(module_path, module, check_name, check_name_camel)
   add_release_notes(module_path, module, check_name)
   test_extension = language_to_extension.get(args.language)

clang-tools-extra/clang-tidy/bugprone/BranchCloneCheck.cpp

@@ -0,0 +1,226 @@
+//===--- BranchCloneCheck.cpp - clang-tidy --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "BranchCloneCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Analysis/CloneDetection.h"
+#include "llvm/Support/Casting.h"
+
+using namespace clang;
+using namespace clang::ast_matchers;
+
+/// Returns true when the statements are Type I clones of each other.
+static bool areStatementsIdentical(const Stmt *LHS, const Stmt *RHS,
+                                   const ASTContext &Context) {
+  llvm::FoldingSetNodeID DataLHS, DataRHS;
+  LHS->Profile(DataLHS, Context, false);
+  RHS->Profile(DataRHS, Context, false);
+  return (DataLHS == DataRHS);
+}
+
+namespace {
+/// A branch in a switch may consist of several statements; while a branch in
+/// an if/else if/else chain is one statement (which may be a CompoundStmt).
+using SwitchBranch = llvm::SmallVector<const Stmt *, 2>;
+} // anonymous namespace
+
+/// Determines if the bodies of two branches in a switch statements are Type I
+/// clones of each other. This function only examines the body of the branch
+/// and ignores the `case X:` or `default:` at the start of the branch.
+static bool areSwitchBranchesIdentical(const SwitchBranch LHS,
+                                       const SwitchBranch RHS,
+                                       const ASTContext &Context) {
+  if (LHS.size() != RHS.size())
+    return false;
+
+  for (size_t i = 0, Size = LHS.size(); i < Size; i++) {
+    // NOTE: We strip goto labels and annotations in addition to stripping
+    // the `case X:` or `default:` labels, but it is very unlikely that this
+    // would casue false positives in real-world code.
+    if (!areStatementsIdentical(LHS[i]->stripLabelLikeStatements(),
+                                RHS[i]->stripLabelLikeStatements(), Context)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+void BranchCloneCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      ifStmt(stmt().bind("if"),
+             hasParent(stmt(unless(ifStmt(hasElse(equalsBoundNode("if")))))),
+             hasElse(stmt().bind("else"))),
+      this);
+  Finder->addMatcher(switchStmt().bind("switch"), this);
+  Finder->addMatcher(conditionalOperator().bind("condOp"), this);
+}
+
+void BranchCloneCheck::check(const MatchFinder::MatchResult &Result) {
+  const ASTContext &Context = *Result.Context;
+
+  if (const auto *IS = Result.Nodes.getNodeAs<IfStmt>("if")) {
+    const Stmt *Then = IS->getThen();
+    assert(Then && "An IfStmt must have a `then` branch!");
+
+    const Stmt *Else = Result.Nodes.getNodeAs<Stmt>("else");
+    assert(Else && "We only look for `if` statements with an `else` branch!");
+
+    if (!isa<IfStmt>(Else)) {
+      // Just a simple if with no `else if` branch.
+      if (areStatementsIdentical(Then->IgnoreContainers(),
+                                 Else->IgnoreContainers(), Context)) {
+        diag(IS->getBeginLoc(), "if with identical then and else branches");
+        diag(IS->getElseLoc(), "else branch starts here", DiagnosticIDs::Note);
+      }
+      return;
+    }
+
+    // This is the complicated case when we start an if/else if/else chain.
+    // To find all the duplicates, we collect all the branches into a vector.
+    llvm::SmallVector<const Stmt *, 4> Branches;
+    const IfStmt *Cur = IS;
+    while (true) {
+      // Store the `then` branch.
+      Branches.push_back(Cur->getThen());
+
+      Else = Cur->getElse();
+      // The chain ends if there is no `else` branch.
+      if (!Else)
+        break;
+
+      // Check if there is another `else if`...
+      Cur = dyn_cast<IfStmt>(Else);
+      if (!Cur) {
+        // ...this is just a plain `else` branch at the end of the chain.
+        Branches.push_back(Else);
+        break;
+      }
+    }
+
+    size_t N = Branches.size();
+    llvm::BitVector KnownAsClone(N);
+
+    for (size_t i = 0; i + 1 < N; i++) {
+      // We have already seen Branches[i] as a clone of an earlier branch.
+      if (KnownAsClone[i])
+        continue;
+
+      int NumCopies = 1;
+
+      for (size_t j = i + 1; j < N; j++) {
+        if (KnownAsClone[j] ||
+            !areStatementsIdentical(Branches[i]->IgnoreContainers(),
+                                    Branches[j]->IgnoreContainers(), Context))
+          continue;
+
+        NumCopies++;
+        KnownAsClone[j] = true;
+
+        if (NumCopies == 2) {
+          // We report the first occurence only when we find the second one.
+          diag(Branches[i]->getBeginLoc(),
+               "repeated branch in conditional chain");
+          diag(Lexer::getLocForEndOfToken(Branches[i]->getEndLoc(), 0,
+                                          *Result.SourceManager, getLangOpts()),
+               "end of the original", DiagnosticIDs::Note);
+        }
+
+        diag(Branches[j]->getBeginLoc(), "clone %0 starts here",
+             DiagnosticIDs::Note)
+            << (NumCopies - 1);
+      }
+    }
+    return;
+  }
+
+  if (const auto *CO = Result.Nodes.getNodeAs<ConditionalOperator>("condOp")) {
+    // We do not try to detect chains of ?: operators.
+    if (areStatementsIdentical(CO->getTrueExpr(), CO->getFalseExpr(), Context))
+      diag(CO->getQuestionLoc(),
+           "conditional operator with identical true and false expressions");
+
+    return;
+  }
+
+  if (const auto *SS = Result.Nodes.getNodeAs<SwitchStmt>("switch")) {
+    const CompoundStmt *Body = dyn_cast_or_null<CompoundStmt>(SS->getBody());
+
+    // Code like
+    //   switch (x) case 0: case 1: foobar();
+    // is legal and calls foobar() if and only if x is either 0 or 1;
+    // but we do not try to distinguish branches in such code.
+    if (!Body)
+      return;
+
+    // We will first collect the branches of the switch statements. For the
+    // sake of simplicity we say that branches are delimited by the SwitchCase
+    // (`case:` or `default:`) children of Body; that is, we ignore `case:` or
+    // `default:` labels embedded inside other statements and we do not follow
+    // the effects of `break` and other manipulation of the control-flow.
+    llvm::SmallVector<SwitchBranch, 4> Branches;
+    for (const Stmt *S : Body->body()) {
+      // If this is a `case` or `default`, we start a new, empty branch.
+      if (isa<SwitchCase>(S))
+        Branches.emplace_back();
+
+      // There may be code before the first branch (which can be dead code
+      // and can be code reached either through goto or through case labels
+      // that are embedded inside e.g. inner compound statements); we do not
+      // store those statements in branches.
+      if (!Branches.empty())
+        Branches.back().push_back(S);
+    }
+
+    auto End = Branches.end();
+    auto BeginCurrent = Branches.begin();
+    while (BeginCurrent < End) {
+      auto EndCurrent = BeginCurrent + 1;
+      while (EndCurrent < End &&
+             areSwitchBranchesIdentical(*BeginCurrent, *EndCurrent, Context)) {
+        ++EndCurrent;
+      }
+      // At this point the iterator range {BeginCurrent, EndCurrent} contains a
+      // complete family of consecutive identical branches.
+      if (EndCurrent > BeginCurrent + 1) {
+        diag(BeginCurrent->front()->getBeginLoc(),
+             "switch has %0 consecutive identical branches")
+            << static_cast<int>(std::distance(BeginCurrent, EndCurrent));
+
+        SourceLocation EndLoc = (EndCurrent - 1)->back()->getEndLoc();
+        // If the case statement is generated from a macro, it's SourceLocation
+        // may be invalid, resuling in an assertation failure down the line.
+        // While not optimal, try the begin location in this case, it's still
+        // better then nothing.
+        if (EndLoc.isInvalid())
+          EndLoc = (EndCurrent - 1)->back()->getBeginLoc();
+
+        if (EndLoc.isMacroID())
+          EndLoc = Context.getSourceManager().getExpansionLoc(EndLoc);
+
+        diag(Lexer::getLocForEndOfToken(EndLoc, 0, *Result.SourceManager,
+                                        getLangOpts()),
+             "last of these clones ends here", DiagnosticIDs::Note);
+      }
+      BeginCurrent = EndCurrent;
+    }
+    return;
+  }
+
+  llvm_unreachable("No if statement and no switch statement.");
+}
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang

clang-tools-extra/clang-tidy/bugprone/BranchCloneCheck.h

@@ -0,0 +1,39 @@
+//===--- BranchCloneCheck.h - clang-tidy ------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_BRANCHCLONECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_BRANCHCLONECHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+/// A check for detecting if/else if/else chains where two or more branches are
+/// Type I clones of each other (that is, they contain identical code), for
+/// detecting switch statements where two or more consecutive branches are
+/// Type I clones of each other, and for detecting conditional operators where
+/// the true and false expressions are Type I clones of each other.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone-branch-clone.html
+class BranchCloneCheck : public ClangTidyCheck {
+public:
+  BranchCloneCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_BRANCHCLONECHECK_H