[clang-tidy] Rename android-file-open-flag and fix a bug

Summary:
1. Rename android-file-open-flag to android-cloexec-open.
2. Handle a case when the function is passed as an argument of a function-like macro.

Reviewers: chh

Reviewed By: chh

Subscribers: srhines, mgorny, JDevlieghere, xazax.hun, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D34633

llvm-svn: 306728

1 files changed, 100 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/android/CloexecOpenCheck.cpp b/clang-tools-extra/clang-tidy/android/CloexecOpenCheck.cpp
new file mode 100644
index 00000000000..4dfe3951d93
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/android/CloexecOpenCheck.cpp
@@ -0,0 +1,100 @@
+//===--- CloexecOpenCheck.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 "CloexecOpenCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+namespace {
+static constexpr const char *O_CLOEXEC = "O_CLOEXEC";
+
+bool hasCloseOnExecFlag(const Expr *Flags, const SourceManager &SM,
+                        const LangOptions &LangOpts) {
+  // If the Flag is an integer constant, check it.
+  if (isa<IntegerLiteral>(Flags)) {
+    if (!SM.isMacroBodyExpansion(Flags->getLocStart()) &&
+        !SM.isMacroArgExpansion(Flags->getLocStart()))
+      return false;
+
+    // Get the Marco name.
+    auto MacroName = Lexer::getSourceText(
+        CharSourceRange::getTokenRange(Flags->getSourceRange()), SM, LangOpts);
+
+    return MacroName == O_CLOEXEC;
+  }
+  // If it's a binary OR operation.
+  if (const auto *BO = dyn_cast<BinaryOperator>(Flags))
+    if (BO->getOpcode() == clang::BinaryOperatorKind::BO_Or)
+      return hasCloseOnExecFlag(BO->getLHS()->IgnoreParenCasts(), SM,
+                                LangOpts) ||
+             hasCloseOnExecFlag(BO->getRHS()->IgnoreParenCasts(), SM, LangOpts);
+
+  // Otherwise, assume it has the flag.
+  return true;
+}
+} // namespace
+
+void CloexecOpenCheck::registerMatchers(MatchFinder *Finder) {
+  auto CharPointerType = hasType(pointerType(pointee(isAnyCharacter())));
+
+  Finder->addMatcher(
+      callExpr(callee(functionDecl(isExternC(), returns(isInteger()),
+                                   hasAnyName("open", "open64"),
+                                   hasParameter(0, CharPointerType),
+                                   hasParameter(1, hasType(isInteger())))
+                          .bind("funcDecl")))
+          .bind("openFn"),
+      this);
+  Finder->addMatcher(
+      callExpr(callee(functionDecl(isExternC(), returns(isInteger()),
+                                   hasName("openat"),
+                                   hasParameter(0, hasType(isInteger())),
+                                   hasParameter(1, CharPointerType),
+                                   hasParameter(2, hasType(isInteger())))
+                          .bind("funcDecl")))
+          .bind("openatFn"),
+      this);
+}
+
+void CloexecOpenCheck::check(const MatchFinder::MatchResult &Result) {
+  const Expr *FlagArg = nullptr;
+  if (const auto *OpenFnCall = Result.Nodes.getNodeAs<CallExpr>("openFn"))
+    FlagArg = OpenFnCall->getArg(1);
+  else if (const auto *OpenFnCall =
+               Result.Nodes.getNodeAs<CallExpr>("openatFn"))
+    FlagArg = OpenFnCall->getArg(2);
+  assert(FlagArg);
+
+  const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>("funcDecl");
+
+  // Check the required flag.
+  SourceManager &SM = *Result.SourceManager;
+  if (hasCloseOnExecFlag(FlagArg->IgnoreParenCasts(), SM,
+                         Result.Context->getLangOpts()))
+    return;
+
+  SourceLocation EndLoc =
+      Lexer::getLocForEndOfToken(SM.getFileLoc(FlagArg->getLocEnd()), 0, SM,
+                                 Result.Context->getLangOpts());
+
+  diag(EndLoc, "%0 should use %1 where possible")
+      << FD << O_CLOEXEC
+      << FixItHint::CreateInsertion(EndLoc, (Twine(" | ") + O_CLOEXEC).str());
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang