vmiklos updated this revision to Diff 174439.
https://reviews.llvm.org/D54349
Files:
clang-tidy/readability/CMakeLists.txt
clang-tidy/readability/ReadabilityTidyModule.cpp
clang-tidy/readability/RedundantPreprocessorCheck.cpp
clang-tidy/readability/RedundantPreprocessorCheck.h
docs/ReleaseNotes.rst
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/readability-redundant-preprocessor.rst
test/clang-tidy/readability-redundant-preprocessor-ifdef.cpp
test/clang-tidy/readability-redundant-preprocessor.cpp
test/clang-tidy/readability-redundant-preprocessor.h
Index: test/clang-tidy/readability-redundant-preprocessor.h
===================================================================
--- /dev/null
+++ test/clang-tidy/readability-redundant-preprocessor.h
@@ -0,0 +1,5 @@
+#ifndef FOO
+#ifndef FOO // this would warn, but not in a header
+void f();
+#endif
+#endif
Index: test/clang-tidy/readability-redundant-preprocessor.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/readability-redundant-preprocessor.cpp
@@ -0,0 +1,84 @@
+// RUN: %check_clang_tidy %s readability-redundant-preprocessor %t -- -- -I %S
+
+// Positive testing.
+#ifndef FOO
+// CHECK-NOTES: [[@LINE+1]]:2: warning: nested redundant #ifndef; consider removing it [readability-redundant-preprocessor]
+#ifndef FOO
+// CHECK-NOTES: [[@LINE-3]]:2: note: previous #ifndef was here
+void f();
+#endif
+#endif
+
+// Positive testing of inverted condition.
+#ifndef FOO
+// CHECK-NOTES: [[@LINE+1]]:2: warning: nested redundant #ifdef; consider removing it [readability-redundant-preprocessor]
+#ifdef FOO
+// CHECK-NOTES: [[@LINE-3]]:2: note: previous #ifndef was here
+void f2();
+#endif
+#endif
+
+// Negative testing.
+#include "readability-redundant-preprocessor.h"
+
+#ifndef BAR
+void g();
+#endif
+
+#ifndef FOO
+#ifndef BAR
+void h();
+#endif
+#endif
+
+#ifndef FOO
+#ifdef BAR
+void i();
+#endif
+#endif
+
+// Positive #if testing.
+#define FOO 4
+
+#if FOO == 4
+// CHECK-NOTES: [[@LINE+1]]:2: warning: nested redundant #if; consider removing it [readability-redundant-preprocessor]
+#if FOO == 4
+// CHECK-NOTES: [[@LINE-3]]:2: note: previous #if was here
+void j();
+#endif
+#endif
+
+#if FOO == 3 + 1
+// CHECK-NOTES: [[@LINE+1]]:2: warning: nested redundant #if; consider removing it [readability-redundant-preprocessor]
+#if FOO == 3 + 1
+// CHECK-NOTES: [[@LINE-3]]:2: note: previous #if was here
+void j();
+#endif
+#endif
+
+#if FOO == \
+ 4
+// CHECK-NOTES: [[@LINE+1]]:2: warning: nested redundant #if; consider removing it [readability-redundant-preprocessor]
+#if FOO == \
+ 4
+// CHECK-NOTES: [[@LINE-5]]:2: note: previous #if was here
+void j();
+#endif
+#endif
+
+// Negative #if testing.
+#define BAR 4
+
+#if FOO == 4
+#if BAR == 4
+void k();
+#endif
+#endif
+
+#if FOO == \
+ 4
+#if BAR == \
+ 5
+void k();
+#endif
+#endif
Index: test/clang-tidy/readability-redundant-preprocessor-ifdef.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/readability-redundant-preprocessor-ifdef.cpp
@@ -0,0 +1,36 @@
+// RUN: %check_clang_tidy %s readability-redundant-preprocessor %t -- -- -DFOO
+
+// Positive testing.
+#ifdef FOO
+// CHECK-NOTES: [[@LINE+1]]:2: warning: nested redundant #ifdef; consider removing it [readability-redundant-preprocessor]
+#ifdef FOO
+// CHECK-NOTES: [[@LINE-3]]:2: note: previous #ifdef was here
+void f();
+#endif
+#endif
+
+// Positive testing of inverted condition.
+#ifdef FOO
+// CHECK-NOTES: [[@LINE+1]]:2: warning: nested redundant #ifndef; consider removing it [readability-redundant-preprocessor]
+#ifndef FOO
+// CHECK-NOTES: [[@LINE-3]]:2: note: previous #ifdef was here
+void f2();
+#endif
+#endif
+
+// Negative testing.
+#ifdef BAR
+void g();
+#endif
+
+#ifdef FOO
+#ifdef BAR
+void h();
+#endif
+#endif
+
+#ifdef FOO
+#ifndef BAR
+void i();
+#endif
+#endif
Index: docs/clang-tidy/checks/readability-redundant-preprocessor.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/readability-redundant-preprocessor.rst
@@ -0,0 +1,61 @@
+.. title:: clang-tidy - readability-redundant-preprocessor
+
+readability-redundant-preprocessor
+==================================
+
+Finds potentially redundant preprocessor directives. At the moment the
+following cases are detected:
+
+* `#ifdef` .. `#endif` pairs which are nested inside an outer pair with the
+ same condition. For example:
+
+.. code-block:: c++
+
+ #ifdef FOO
+ #ifdef FOO // inner ifdef is considered redundant
+ void f();
+ #endif
+ #endif
+
+* Same for `#ifndef` .. `#endif` pairs. For example:
+
+.. code-block:: c++
+
+ #ifndef FOO
+ #ifndef FOO // inner ifndef is considered redundant
+ void f();
+ #endif
+ #endif
+
+* `#ifndef` inside an `#ifdef` with the same condition:
+
+.. code-block:: c++
+
+ #ifdef FOO
+ #ifndef FOO // inner ifndef is considered redundant
+ void f();
+ #endif
+ #endif
+
+* `#ifdef` inside an `#ifndef` with the same condition:
+
+.. code-block:: c++
+
+ #ifndef FOO
+ #ifdef FOO // inner ifdef is considered redundant
+ void f();
+ #endif
+ #endif
+
+* `#if` .. `#endif` pairs which are nested inside an outer pair with the same
+ condition. For example:
+
+.. code-block:: c++
+
+ #define FOO 4
+ #if FOO == 4
+ #if FOO == 4 // inner if is considered redundant
+ void f();
+ #endif
+ #endif
+
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -248,6 +248,7 @@
readability-redundant-declaration
readability-redundant-function-ptr-dereference
readability-redundant-member-init
+ readability-redundant-preprocessor
readability-redundant-smartptr-get
readability-redundant-string-cstr
readability-redundant-string-init
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -167,6 +167,11 @@
Detects usage of magic numbers, numbers that are used as literals instead of
introduced via constants or symbols.
+- New :doc:`readability-redundant-preprocessor
+ <clang-tidy/checks/readability-redundant-preprocessor>` check.
+
+ Finds potentially redundant preprocessor directives.
+
- New :doc:`readability-uppercase-literal-suffix
<clang-tidy/checks/readability-uppercase-literal-suffix>` check.
Index: clang-tidy/readability/RedundantPreprocessorCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/readability/RedundantPreprocessorCheck.h
@@ -0,0 +1,35 @@
+//===--- RedundantPreprocessorCheck.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_READABILITY_REDUNDANTPREPROCESSORCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_REDUNDANTPREPROCESSORCHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+/// This check flags redundant preprocessor directives: nested directives with
+/// the same condition.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability-redundant-preprocessor.html
+class RedundantPreprocessorCheck : public ClangTidyCheck {
+public:
+ RedundantPreprocessorCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerPPCallbacks(CompilerInstance &Compiler) override;
+};
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_REDUNDANTPREPROCESSORCHECK_H
Index: clang-tidy/readability/RedundantPreprocessorCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/readability/RedundantPreprocessorCheck.cpp
@@ -0,0 +1,109 @@
+//===--- RedundantPreprocessorCheck.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 "RedundantPreprocessorCheck.h"
+#include "clang/Frontend/CompilerInstance.h"
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+namespace {
+/// Information about an opening preprocessor directive.
+struct PreprocessorEntry {
+ SourceLocation Loc;
+ /// Condition used after the preprocessor directive.
+ std::string Condition;
+};
+
+class RedundantPreprocessorCallbacks : public PPCallbacks {
+ enum DirectiveKind { DK_If = 0, DK_Ifdef = 1, DK_Ifndef = 2 };
+
+public:
+ explicit RedundantPreprocessorCallbacks(ClangTidyCheck &Check,
+ Preprocessor &PP)
+ : Check(Check), PP(PP),
+ WarningDescription("nested redundant %select{#if|#ifdef|#ifndef}0; "
+ "consider removing it"),
+ NoteDescription("previous %select{#if|#ifdef|#ifndef}0 was here") {}
+
+ void If(SourceLocation Loc, SourceRange ConditionRange,
+ ConditionValueKind ConditionValue) override {
+ StringRef Condition =
+ Lexer::getSourceText(CharSourceRange::getTokenRange(ConditionRange),
+ PP.getSourceManager(), PP.getLangOpts());
+ CheckMacroRedundancy(Loc, Condition, IfStack, DK_If, DK_If, true);
+ }
+
+ void Ifdef(SourceLocation Loc, const Token &MacroNameTok,
+ const MacroDefinition &MacroDefinition) override {
+ std::string MacroName = PP.getSpelling(MacroNameTok);
+ CheckMacroRedundancy(Loc, MacroName, IfdefStack, DK_Ifdef, DK_Ifdef, true);
+ CheckMacroRedundancy(Loc, MacroName, IfndefStack, DK_Ifdef, DK_Ifndef,
+ false);
+ }
+
+ void Ifndef(SourceLocation Loc, const Token &MacroNameTok,
+ const MacroDefinition &MacroDefinition) override {
+ std::string MacroName = PP.getSpelling(MacroNameTok);
+ CheckMacroRedundancy(Loc, MacroName, IfndefStack, DK_Ifndef, DK_Ifndef,
+ true);
+ CheckMacroRedundancy(Loc, MacroName, IfdefStack, DK_Ifndef, DK_Ifdef,
+ false);
+ }
+
+ void Endif(SourceLocation Loc, SourceLocation IfLoc) override {
+ if (!IfStack.empty() && IfLoc == IfStack.back().Loc)
+ IfStack.pop_back();
+ if (!IfdefStack.empty() && IfLoc == IfdefStack.back().Loc)
+ IfdefStack.pop_back();
+ if (!IfndefStack.empty() && IfLoc == IfndefStack.back().Loc)
+ IfndefStack.pop_back();
+ }
+
+private:
+ void CheckMacroRedundancy(SourceLocation Loc, StringRef MacroName,
+ SmallVector<PreprocessorEntry, 4> &Stack,
+ DirectiveKind WarningKind, DirectiveKind NoteKind,
+ bool Store) {
+ if (PP.getSourceManager().isInMainFile(Loc)) {
+ for (const auto &Entry : Stack) {
+ if (Entry.Condition == MacroName) {
+ Check.diag(Loc, WarningDescription) << WarningKind;
+ Check.diag(Entry.Loc, NoteDescription, DiagnosticIDs::Note)
+ << NoteKind;
+ }
+ }
+ }
+
+ if (Store)
+ // This is an actual directive to be remembered.
+ Stack.push_back({Loc, MacroName});
+ }
+
+ ClangTidyCheck &Check;
+ Preprocessor &PP;
+ SmallVector<PreprocessorEntry, 4> IfStack;
+ SmallVector<PreprocessorEntry, 4> IfdefStack;
+ SmallVector<PreprocessorEntry, 4> IfndefStack;
+ const std::string WarningDescription;
+ const std::string NoteDescription;
+};
+} // namespace
+
+void RedundantPreprocessorCheck::registerPPCallbacks(
+ CompilerInstance &Compiler) {
+ Compiler.getPreprocessor().addPPCallbacks(
+ ::llvm::make_unique<RedundantPreprocessorCallbacks>(
+ *this, Compiler.getPreprocessor()));
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/readability/ReadabilityTidyModule.cpp
===================================================================
--- clang-tidy/readability/ReadabilityTidyModule.cpp
+++ clang-tidy/readability/ReadabilityTidyModule.cpp
@@ -31,6 +31,7 @@
#include "RedundantDeclarationCheck.h"
#include "RedundantFunctionPtrDereferenceCheck.h"
#include "RedundantMemberInitCheck.h"
+#include "RedundantPreprocessorCheck.h"
#include "RedundantSmartptrGetCheck.h"
#include "RedundantStringCStrCheck.h"
#include "RedundantStringInitCheck.h"
@@ -83,6 +84,8 @@
"readability-redundant-function-ptr-dereference");
CheckFactories.registerCheck<RedundantMemberInitCheck>(
"readability-redundant-member-init");
+ CheckFactories.registerCheck<RedundantPreprocessorCheck>(
+ "readability-redundant-preprocessor");
CheckFactories.registerCheck<SimplifySubscriptExprCheck>(
"readability-simplify-subscript-expr");
CheckFactories.registerCheck<StaticAccessedThroughInstanceCheck>(
Index: clang-tidy/readability/CMakeLists.txt
===================================================================
--- clang-tidy/readability/CMakeLists.txt
+++ clang-tidy/readability/CMakeLists.txt
@@ -24,6 +24,7 @@
RedundantDeclarationCheck.cpp
RedundantFunctionPtrDereferenceCheck.cpp
RedundantMemberInitCheck.cpp
+ RedundantPreprocessorCheck.cpp
RedundantSmartptrGetCheck.cpp
RedundantStringCStrCheck.cpp
RedundantStringInitCheck.cpp
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