[clang-tools-extra] 7e3ea55 - [clang-tidy] modernize-deprecated-headers check should respect extern "C" blocks
Balazs Benics via cfe-commits
cfe-commits at lists.llvm.org
Fri May 13 07:54:30 PDT 2022
Author: Balazs Benics
Date: 2022-05-13T16:54:13+02:00
New Revision: 7e3ea55da88a9d7feaa22f29d51f89fd0152a189
URL: https://github.com/llvm/llvm-project/commit/7e3ea55da88a9d7feaa22f29d51f89fd0152a189
DIFF: https://github.com/llvm/llvm-project/commit/7e3ea55da88a9d7feaa22f29d51f89fd0152a189.diff
LOG: [clang-tidy] modernize-deprecated-headers check should respect extern "C" blocks
The check should not report includes wrapped by `extern "C" { ... }` blocks,
such as:
```lang=C++
#ifdef __cplusplus
extern "C" {
#endif
#include "assert.h"
#ifdef __cplusplus
}
#endif
```
This pattern comes up sometimes in header files designed to be consumed
by both C and C++ source files.
The check now reports false reports when the header file is consumed by
a C++ translation unit.
In this change, I'm not emitting the reports immediately from the
`PPCallback`, rather aggregating them for further processing.
After all preprocessing is done, the matcher will be called on the
`TranslationUnitDecl`, ensuring that the check callback is called only
once.
Within that callback, I'm recursively visiting each decls, looking for
`LinkageSpecDecls` which represent the `extern "C"` specifier.
After this, I'm dropping all the reports coming from inside of it.
After the visitation is done, I'm emitting the reports I'm left with.
For performance reasons, I'm sorting the `IncludeMarkers` by their
corresponding locations.
This makes the scan `O(log(N)` when looking up the `IncludeMarkers`
affected by the given `extern "C"` block. For this, I'm using
`lower_bound()` and `upper_bound()`.
Reviewed By: whisperity
Differential Revision: https://reviews.llvm.org/D125209
Added:
clang-tools-extra/test/clang-tidy/checkers/Inputs/modernize-deprecated-headers/mylib.h
clang-tools-extra/test/clang-tidy/checkers/modernize-deprecated-headers-extern-c.cpp
Modified:
clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.cpp
clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.h
clang-tools-extra/docs/ReleaseNotes.rst
Removed:
################################################################################
diff --git a/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.cpp b/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.cpp
index 0b44bdaafe23..dd991221faab 100644
--- a/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.cpp
@@ -7,23 +7,37 @@
//===----------------------------------------------------------------------===//
#include "DeprecatedHeadersCheck.h"
+#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Lex/PPCallbacks.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringSet.h"
+#include <algorithm>
#include <vector>
namespace clang {
namespace tidy {
namespace modernize {
+namespace detail {
+bool operator<(const IncludeMarker &LHS, const IncludeMarker &RHS) {
+ return LHS.DecomposedDiagLoc < RHS.DecomposedDiagLoc;
+}
+bool operator<(const IncludeMarker &LHS,
+ const std::pair<FileID, unsigned> &RHS) {
+ return LHS.DecomposedDiagLoc < RHS;
+}
+bool operator<(const std::pair<FileID, unsigned> &LHS,
+ const IncludeMarker &RHS) {
+ return LHS < RHS.DecomposedDiagLoc;
+}
-namespace {
class IncludeModernizePPCallbacks : public PPCallbacks {
public:
- explicit IncludeModernizePPCallbacks(ClangTidyCheck &Check,
- LangOptions LangOpts);
+ explicit IncludeModernizePPCallbacks(DeprecatedHeadersCheck &Check,
+ LangOptions LangOpts,
+ const SourceManager &SM);
void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
StringRef FileName, bool IsAngled,
@@ -33,22 +47,98 @@ class IncludeModernizePPCallbacks : public PPCallbacks {
SrcMgr::CharacteristicKind FileType) override;
private:
- ClangTidyCheck &Check;
+ DeprecatedHeadersCheck &Check;
LangOptions LangOpts;
llvm::StringMap<std::string> CStyledHeaderToCxx;
llvm::StringSet<> DeleteHeaders;
+ const SourceManager &SM;
+};
+
+class ExternCRefutationVisitor
+ : public RecursiveASTVisitor<ExternCRefutationVisitor> {
+ std::vector<IncludeMarker> &IncludesToBeProcessed;
+ const SourceManager &SM;
+
+public:
+ ExternCRefutationVisitor(std::vector<IncludeMarker> &IncludesToBeProcessed,
+ SourceManager &SM)
+ : IncludesToBeProcessed(IncludesToBeProcessed), SM(SM) {}
+ bool shouldWalkTypesOfTypeLocs() const { return false; }
+ bool shouldVisitLambdaBody() const { return false; }
+
+ bool VisitLinkageSpecDecl(LinkageSpecDecl *LinkSpecDecl) const {
+ if (LinkSpecDecl->getLanguage() != LinkageSpecDecl::lang_c ||
+ !LinkSpecDecl->hasBraces())
+ return true;
+
+ auto ExternCBlockBegin =
+ SM.getDecomposedExpansionLoc(LinkSpecDecl->getBeginLoc());
+ auto ExternCBlockEnd =
+ SM.getDecomposedExpansionLoc(LinkSpecDecl->getEndLoc());
+
+ auto Begin = IncludesToBeProcessed.begin();
+ auto End = IncludesToBeProcessed.end();
+ auto Low = std::lower_bound(Begin, End, ExternCBlockBegin);
+ auto Up = std::upper_bound(Low, End, ExternCBlockEnd);
+ IncludesToBeProcessed.erase(Low, Up);
+ return true;
+ }
};
-} // namespace
+} // namespace detail
void DeprecatedHeadersCheck::registerPPCallbacks(
const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
- PP->addPPCallbacks(
- ::std::make_unique<IncludeModernizePPCallbacks>(*this, getLangOpts()));
+ PP->addPPCallbacks(::std::make_unique<detail::IncludeModernizePPCallbacks>(
+ *this, getLangOpts(), PP->getSourceManager()));
+}
+void DeprecatedHeadersCheck::registerMatchers(
+ ast_matchers::MatchFinder *Finder) {
+ // Even though the checker operates on a "preprocessor" level, we still need
+ // to act on a "TranslationUnit" to acquire the AST where we can walk each
+ // Decl and look for `extern "C"` blocks where we will suppress the report we
+ // collected during the preprocessing phase.
+ // The `onStartOfTranslationUnit()` won't suffice, since we need some handle
+ // to the `ASTContext`.
+ Finder->addMatcher(ast_matchers::translationUnitDecl().bind("TU"), this);
+}
+
+void DeprecatedHeadersCheck::onEndOfTranslationUnit() {
+ IncludesToBeProcessed.clear();
+}
+
+void DeprecatedHeadersCheck::check(
+ const ast_matchers::MatchFinder::MatchResult &Result) {
+ SourceManager &SM = Result.Context->getSourceManager();
+ using detail::IncludeMarker;
+
+ llvm::sort(IncludesToBeProcessed);
+
+ // Suppress includes wrapped by `extern "C" { ... }` blocks.
+ detail::ExternCRefutationVisitor Visitor(IncludesToBeProcessed, SM);
+ Visitor.TraverseAST(*Result.Context);
+
+ // Emit all the remaining reports.
+ for (const IncludeMarker &Entry : IncludesToBeProcessed) {
+ SourceLocation DiagLoc = SM.getComposedLoc(Entry.DecomposedDiagLoc.first,
+ Entry.DecomposedDiagLoc.second);
+ if (Entry.Replacement.empty()) {
+ diag(DiagLoc, "including '%0' has no effect in C++; consider removing it")
+ << Entry.FileName << FixItHint::CreateRemoval(Entry.ReplacementRange);
+ } else {
+ diag(DiagLoc, "inclusion of deprecated C++ header "
+ "'%0'; consider using '%1' instead")
+ << Entry.FileName << Entry.Replacement
+ << FixItHint::CreateReplacement(
+ Entry.ReplacementRange,
+ (llvm::Twine("<") + Entry.Replacement + ">").str());
+ }
+ }
}
-IncludeModernizePPCallbacks::IncludeModernizePPCallbacks(ClangTidyCheck &Check,
- LangOptions LangOpts)
- : Check(Check), LangOpts(LangOpts) {
+detail::IncludeModernizePPCallbacks::IncludeModernizePPCallbacks(
+ DeprecatedHeadersCheck &Check, LangOptions LangOpts,
+ const SourceManager &SM)
+ : Check(Check), LangOpts(LangOpts), SM(SM) {
for (const auto &KeyValue :
std::vector<std::pair<llvm::StringRef, std::string>>(
{{"assert.h", "cassert"},
@@ -89,7 +179,7 @@ IncludeModernizePPCallbacks::IncludeModernizePPCallbacks(ClangTidyCheck &Check,
}
}
-void IncludeModernizePPCallbacks::InclusionDirective(
+void detail::IncludeModernizePPCallbacks::InclusionDirective(
SourceLocation HashLoc, const Token &IncludeTok, StringRef FileName,
bool IsAngled, CharSourceRange FilenameRange, Optional<FileEntryRef> File,
StringRef SearchPath, StringRef RelativePath, const Module *Imported,
@@ -101,19 +191,16 @@ void IncludeModernizePPCallbacks::InclusionDirective(
// 1. Insert std prefix for every such symbol occurrence.
// 2. Insert `using namespace std;` to the beginning of TU.
// 3. Do nothing and let the user deal with the migration himself.
+ std::pair<FileID, unsigned> DiagLoc =
+ SM.getDecomposedExpansionLoc(FilenameRange.getBegin());
if (CStyledHeaderToCxx.count(FileName) != 0) {
- std::string Replacement =
- (llvm::Twine("<") + CStyledHeaderToCxx[FileName] + ">").str();
- Check.diag(FilenameRange.getBegin(), "inclusion of deprecated C++ header "
- "'%0'; consider using '%1' instead")
- << FileName << CStyledHeaderToCxx[FileName]
- << FixItHint::CreateReplacement(FilenameRange.getAsRange(),
- Replacement);
+ Check.IncludesToBeProcessed.push_back(
+ IncludeMarker{CStyledHeaderToCxx[FileName], FileName,
+ FilenameRange.getAsRange(), DiagLoc});
} else if (DeleteHeaders.count(FileName) != 0) {
- Check.diag(FilenameRange.getBegin(),
- "including '%0' has no effect in C++; consider removing it")
- << FileName << FixItHint::CreateRemoval(
- SourceRange(HashLoc, FilenameRange.getEnd()));
+ Check.IncludesToBeProcessed.push_back(
+ IncludeMarker{std::string{}, FileName,
+ SourceRange{HashLoc, FilenameRange.getEnd()}, DiagLoc});
}
}
diff --git a/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.h b/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.h
index 113b0ca182e0..1b76ca2ba2bb 100644
--- a/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.h
@@ -15,6 +15,22 @@ namespace clang {
namespace tidy {
namespace modernize {
+namespace detail {
+class IncludeModernizePPCallbacks;
+class ExternCRefutationVisitor;
+struct IncludeMarker {
+ std::string Replacement;
+ StringRef FileName;
+ SourceRange ReplacementRange;
+ std::pair<FileID, unsigned> DecomposedDiagLoc;
+};
+bool operator<(const IncludeMarker &LHS, const IncludeMarker &RHS);
+bool operator<(const IncludeMarker &LHS,
+ const std::pair<FileID, unsigned> &RHS);
+bool operator<(const std::pair<FileID, unsigned> &LHS,
+ const IncludeMarker &RHS);
+} // namespace detail
+
/// This check replaces deprecated C library headers with their C++ STL
/// alternatives.
///
@@ -41,6 +57,14 @@ class DeprecatedHeadersCheck : public ClangTidyCheck {
}
void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
Preprocessor *ModuleExpanderPP) override;
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void onEndOfTranslationUnit() override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+ friend class detail::IncludeModernizePPCallbacks;
+ friend class detail::ExternCRefutationVisitor;
+ std::vector<detail::IncludeMarker> IncludesToBeProcessed;
};
} // namespace modernize
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 00124b0cad75..806e5d10a5fd 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -170,6 +170,11 @@ Changes in existing checks
<clang-tidy/checks/misc-redundant-expression>` involving assignments in
conditions. This fixes `Issue 35853 <https://github.com/llvm/llvm-project/issues/35853>`_.
+- Fixed a false positive in :doc:`modernize-deprecated-headers
+ <clang-tidy/checks/modernize-deprecated-headers>` involving including
+ C header files from C++ files wrapped by ``extern "C" { ... }`` blocks.
+ Such includes will be ignored by now.
+
- Improved :doc:`performance-inefficient-vector-operation
<clang-tidy/checks/performance-inefficient-vector-operation>` to work when
the vector is a member of a structure.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/Inputs/modernize-deprecated-headers/mylib.h b/clang-tools-extra/test/clang-tidy/checkers/Inputs/modernize-deprecated-headers/mylib.h
new file mode 100644
index 000000000000..e6adb8fd98e8
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/Inputs/modernize-deprecated-headers/mylib.h
@@ -0,0 +1 @@
+#include "assert.h"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize-deprecated-headers-extern-c.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize-deprecated-headers-extern-c.cpp
new file mode 100644
index 000000000000..344f7ac5a289
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize-deprecated-headers-extern-c.cpp
@@ -0,0 +1,53 @@
+// RUN: %check_clang_tidy -std=c++11-or-later %s modernize-deprecated-headers %t \
+// RUN: -- -header-filter='.*' -system-headers \
+// RUN: -extra-arg-before=-isystem%S/Inputs/modernize-deprecated-headers
+
+#define EXTERN_C extern "C"
+
+extern "C++" {
+// We should still have the warnings here.
+#include <stdbool.h>
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: including 'stdbool.h' has no effect in C++; consider removing it [modernize-deprecated-headers]
+}
+
+#include <assert.h>
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: inclusion of deprecated C++ header 'assert.h'; consider using 'cassert' instead [modernize-deprecated-headers]
+// CHECK-FIXES: {{^}}#include <cassert>{{$}}
+
+#include <stdbool.h>
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: including 'stdbool.h' has no effect in C++; consider removing it [modernize-deprecated-headers]
+
+#include <mylib.h>
+// CHECK-MESSAGES: mylib.h:1:10: warning: inclusion of deprecated C++ header 'assert.h'; consider using 'cassert' instead [modernize-deprecated-headers]
+
+namespace wrapping {
+extern "C" {
+#include <assert.h> // no-warning
+#include <mylib.h> // no-warning
+#include <stdbool.h> // no-warning
+}
+} // namespace wrapping
+
+extern "C" {
+namespace wrapped {
+#include <assert.h> // no-warning
+#include <mylib.h> // no-warning
+#include <stdbool.h> // no-warning
+} // namespace wrapped
+}
+
+namespace wrapping {
+extern "C" {
+namespace wrapped {
+#include <assert.h> // no-warning
+#include <mylib.h> // no-warning
+#include <stdbool.h> // no-warning
+} // namespace wrapped
+}
+} // namespace wrapping
+
+EXTERN_C {
+#include <assert.h> // no-warning
+#include <mylib.h> // no-warning
+#include <stdbool.h> // no-warning
+}
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