[clang-tools-extra] [clang-tidy] warn when `true` is used as a preprocessor keyword in C (PR #128265)
via cfe-commits
cfe-commits at lists.llvm.org
Sat Feb 22 16:04:26 PST 2025
https://github.com/isuckatcs updated https://github.com/llvm/llvm-project/pull/128265
>From c13cf10fe9f63c4fa361985388ab1ab6c7e55514 Mon Sep 17 00:00:00 2001
From: isuckatcs <65320245+isuckatcs at users.noreply.github.com>
Date: Mon, 17 Feb 2025 22:50:49 +0100
Subject: [PATCH 1/5] add new check
---
.../bugprone/BugproneTidyModule.cpp | 3 +
.../clang-tidy/bugprone/CMakeLists.txt | 1 +
.../clang-tidy/bugprone/TrueMacroCheck.cpp | 97 +++++++++++++++++++
.../clang-tidy/bugprone/TrueMacroCheck.h | 29 ++++++
clang-tools-extra/docs/ReleaseNotes.rst | 5 +
.../clang-tidy/checks/bugprone/true-macro.rst | 6 ++
.../docs/clang-tidy/checks/list.rst | 1 +
.../clang-tidy/checkers/bugprone/true-macro.c | 14 +++
8 files changed, 156 insertions(+)
create mode 100644 clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
create mode 100644 clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
create mode 100644 clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c
diff --git a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
index c5f0b5b28418f..2893d7871a710 100644
--- a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -85,6 +85,7 @@
#include "TerminatingContinueCheck.h"
#include "ThrowKeywordMissingCheck.h"
#include "TooSmallLoopVariableCheck.h"
+#include "TrueMacroCheck.h"
#include "UncheckedOptionalAccessCheck.h"
#include "UndefinedMemoryManipulationCheck.h"
#include "UndelegatedConstructorCheck.h"
@@ -247,6 +248,8 @@ class BugproneModule : public ClangTidyModule {
"bugprone-throw-keyword-missing");
CheckFactories.registerCheck<TooSmallLoopVariableCheck>(
"bugprone-too-small-loop-variable");
+ CheckFactories.registerCheck<TrueMacroCheck>(
+ "bugprone-true-macro");
CheckFactories.registerCheck<UncheckedOptionalAccessCheck>(
"bugprone-unchecked-optional-access");
CheckFactories.registerCheck<UndefinedMemoryManipulationCheck>(
diff --git a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
index e8309c68b7fca..e479c3c137809 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -86,6 +86,7 @@ add_clang_library(clangTidyBugproneModule STATIC
TerminatingContinueCheck.cpp
ThrowKeywordMissingCheck.cpp
TooSmallLoopVariableCheck.cpp
+ TrueMacroCheck.cpp
UncheckedOptionalAccessCheck.cpp
UndefinedMemoryManipulationCheck.cpp
UndelegatedConstructorCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
new file mode 100644
index 0000000000000..a1940a1015af1
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
@@ -0,0 +1,97 @@
+//===--- TrueMacroCheck.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 "TrueMacroCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/PPCallbacks.h"
+#include "clang/Lex/Preprocessor.h"
+#include <iostream>
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+namespace {
+
+class MacroCallback : public PPCallbacks {
+ static constexpr const char *TrueMacroSpelling = "true";
+
+public:
+ MacroCallback(TrueMacroCheck *Check, const SourceManager &SM,
+ Preprocessor *PP)
+ : Check(Check), SM(&SM), PP(PP) {}
+ void MacroDefined(const Token &MacroNameTok,
+ const MacroDirective *MD) override {
+ if (PP->getSpelling(MacroNameTok) == TrueMacroSpelling)
+ TrueDefined = true;
+ }
+
+ virtual void MacroUndefined(const Token &MacroNameTok,
+ const MacroDefinition &MD,
+ const MacroDirective *Undef) override {
+ if (PP->getSpelling(MacroNameTok) == TrueMacroSpelling)
+ TrueDefined = false;
+ }
+
+ virtual void If(SourceLocation Loc, SourceRange ConditionRange,
+ ConditionValueKind ConditionValue) override {
+ StringRef Condition =
+ Lexer::getSourceText(CharSourceRange::getTokenRange(ConditionRange),
+ PP->getSourceManager(), PP->getLangOpts());
+
+ for (auto &&Identifier : identifiersInCondition(Condition))
+ std::cout << Identifier.str() << ' ' << Identifier.size() << '\n';
+ }
+
+private:
+ void emitDiagnostic() {}
+
+ std::vector<StringRef> identifiersInCondition(StringRef Condition) {
+ const static auto Start = [](char C) {
+ return C == '_' || ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z');
+ };
+
+ const static auto Continue = [](char C) {
+ return ('0' <= C && C <= '9') || Start(C);
+ };
+
+ std::vector<StringRef> Identifiers;
+ const char *Str = nullptr;
+
+ for (size_t I = 0; I < Condition.size(); ++I) {
+ char C = Condition[I];
+
+ if (!Str && Start(C)) {
+ Str = Condition.begin() + I;
+ } else if (Str && !Continue(C)) {
+ Identifiers.emplace_back(Str, Condition.begin() + I - Str);
+ Str = nullptr;
+ }
+ }
+
+ if (Str)
+ Identifiers.emplace_back(Str, Condition.end() - Str);
+
+ return Identifiers;
+ }
+
+ bool TrueDefined = false;
+
+ TrueMacroCheck *Check;
+ const SourceManager *SM;
+ Preprocessor *PP;
+};
+} // namespace
+
+void TrueMacroCheck::registerPPCallbacks(const SourceManager &SM,
+ Preprocessor *PP,
+ Preprocessor *ModuleExpanderPP) {
+ PP->addPPCallbacks(std::make_unique<MacroCallback>(this, SM, PP));
+}
+
+} // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
new file mode 100644
index 0000000000000..ca6e5a7bfa64b
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
@@ -0,0 +1,29 @@
+//===--- TrueMacroCheck.h - clang-tidy --------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_TRUEMACROCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_TRUEMACROCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::bugprone {
+
+class TrueMacroCheck : public ClangTidyCheck {
+public:
+ TrueMacroCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
+ Preprocessor *ModuleExpanderPP) override;
+ bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+ return !LangOpts.CPlusPlus;
+ }
+};
+
+} // namespace clang::tidy::bugprone
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_TRUEMACROCHECK_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6b8fe22242417..49220fbb39836 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -91,6 +91,11 @@ Improvements to clang-tidy
New checks
^^^^^^^^^^
+- New :doc:`bugprone-true-macro
+ <clang-tidy/checks/bugprone/true-macro>` check.
+
+ FIXME: Write a short description.
+
New check aliases
^^^^^^^^^^^^^^^^^
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
new file mode 100644
index 0000000000000..70b313774ef15
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
@@ -0,0 +1,6 @@
+.. title:: clang-tidy - bugprone-true-macro
+
+bugprone-true-macro
+===================
+
+FIXME: Describe what patterns does the check detect and why. Give examples.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index 7b9b905ef7671..2940e8ee7248a 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -153,6 +153,7 @@ Clang-Tidy Checks
:doc:`bugprone-terminating-continue <bugprone/terminating-continue>`, "Yes"
:doc:`bugprone-throw-keyword-missing <bugprone/throw-keyword-missing>`,
:doc:`bugprone-too-small-loop-variable <bugprone/too-small-loop-variable>`,
+ :doc:`bugprone-true-macro <bugprone/true-macro>`, "Yes"
:doc:`bugprone-unchecked-optional-access <bugprone/unchecked-optional-access>`,
:doc:`bugprone-undefined-memory-manipulation <bugprone/undefined-memory-manipulation>`,
:doc:`bugprone-undelegated-constructor <bugprone/undelegated-constructor>`,
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c
new file mode 100644
index 0000000000000..25ce8b63bb4cd
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c
@@ -0,0 +1,14 @@
+// RUN: %check_clang_tidy -std=c99-or-later %s bugprone-true-macro %t
+
+// FIXME: Add something that triggers the check here.
+void f();
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: function 'f' is insufficiently awesome [bugprone-true-macro]
+
+// FIXME: Verify the applied fix.
+// * Make the CHECK patterns specific enough and try to make verified lines
+// unique to avoid incorrect matches.
+// * Use {{}} for regular expressions.
+// CHECK-FIXES: {{^}}void awesome_f();{{$}}
+
+// FIXME: Add something that doesn't trigger the check here.
+void awesome_f2();
>From 92170548bd83e4f396854452c9a16220e224a22c Mon Sep 17 00:00:00 2001
From: isuckatcs <65320245+isuckatcs at users.noreply.github.com>
Date: Tue, 18 Feb 2025 23:04:44 +0100
Subject: [PATCH 2/5] implement check
---
.../clang-tidy/bugprone/TrueMacroCheck.cpp | 46 +++++++++++++++----
1 file changed, 36 insertions(+), 10 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
index a1940a1015af1..4b1375db34039 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
@@ -7,11 +7,9 @@
//===----------------------------------------------------------------------===//
#include "TrueMacroCheck.h"
-#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/PPCallbacks.h"
#include "clang/Lex/Preprocessor.h"
-#include <iostream>
using namespace clang::ast_matchers;
@@ -22,11 +20,20 @@ class MacroCallback : public PPCallbacks {
static constexpr const char *TrueMacroSpelling = "true";
public:
- MacroCallback(TrueMacroCheck *Check, const SourceManager &SM,
- Preprocessor *PP)
- : Check(Check), SM(&SM), PP(PP) {}
+ MacroCallback(TrueMacroCheck *Check, Preprocessor *PP)
+ : Check(Check), PP(PP) {}
void MacroDefined(const Token &MacroNameTok,
const MacroDirective *MD) override {
+ if (TrueDefined)
+ return;
+
+ const MacroInfo *MI = MD->getMacroInfo();
+ for (const Token &Tok : MI->tokens()) {
+ if (PP->getSpelling(Tok) == TrueMacroSpelling)
+ emitDiagnostics(Tok.getLocation(),
+ {Tok.getLocation(), Tok.getEndLoc()});
+ }
+
if (PP->getSpelling(MacroNameTok) == TrueMacroSpelling)
TrueDefined = true;
}
@@ -44,12 +51,32 @@ class MacroCallback : public PPCallbacks {
Lexer::getSourceText(CharSourceRange::getTokenRange(ConditionRange),
PP->getSourceManager(), PP->getLangOpts());
- for (auto &&Identifier : identifiersInCondition(Condition))
- std::cout << Identifier.str() << ' ' << Identifier.size() << '\n';
+ if (!TrueDefined && Condition == TrueMacroSpelling) {
+ emitDiagnostics(ConditionRange.getBegin(), ConditionRange);
+ return;
+ }
+
+ for (auto &&Identifier : identifiersInCondition(Condition)) {
+ if (!TrueDefined && Identifier == TrueMacroSpelling) {
+ emitDiagnostics(Loc, {}, true);
+ break;
+ }
+ }
}
private:
- void emitDiagnostic() {}
+ void emitDiagnostics(SourceLocation Loc, SourceRange ReplaceRange,
+ bool InCondition = false) {
+ DiagnosticBuilder Builder =
+ Check->diag(Loc, "in C 'true'%select{| in the condition}0 is treated "
+ "as an undefined "
+ "macro and evaluates to a falsy value; "
+ "consider replacing it with '1'")
+ << InCondition;
+
+ if (!InCondition)
+ Builder << FixItHint::CreateReplacement(ReplaceRange, "1");
+ }
std::vector<StringRef> identifiersInCondition(StringRef Condition) {
const static auto Start = [](char C) {
@@ -83,7 +110,6 @@ class MacroCallback : public PPCallbacks {
bool TrueDefined = false;
TrueMacroCheck *Check;
- const SourceManager *SM;
Preprocessor *PP;
};
} // namespace
@@ -91,7 +117,7 @@ class MacroCallback : public PPCallbacks {
void TrueMacroCheck::registerPPCallbacks(const SourceManager &SM,
Preprocessor *PP,
Preprocessor *ModuleExpanderPP) {
- PP->addPPCallbacks(std::make_unique<MacroCallback>(this, SM, PP));
+ PP->addPPCallbacks(std::make_unique<MacroCallback>(this, PP));
}
} // namespace clang::tidy::bugprone
>From f6aefcb282e7129a668bb64ebc56c4863efdae59 Mon Sep 17 00:00:00 2001
From: isuckatcs <65320245+isuckatcs at users.noreply.github.com>
Date: Sat, 22 Feb 2025 03:14:04 +0100
Subject: [PATCH 3/5] started testing and writing docs
---
.../clang-tidy/bugprone/TrueMacroCheck.h | 5 +++++
clang-tools-extra/docs/ReleaseNotes.rst | 2 +-
.../clang-tidy/checks/bugprone/true-macro.rst | 16 +++++++++++++++-
.../checkers/bugprone/true-macro-condition.c | 10 ++++++++++
.../checkers/bugprone/true-macro-defintion.c | 5 +++++
.../clang-tidy/checkers/bugprone/true-macro.c | 14 --------------
6 files changed, 36 insertions(+), 16 deletions(-)
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
delete mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c
diff --git a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
index ca6e5a7bfa64b..24116dfcbeb4e 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
@@ -13,6 +13,11 @@
namespace clang::tidy::bugprone {
+/// This check gives a warning if `true` is used in the preprocessor when not
+/// defined in C.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/true-macro.html
class TrueMacroCheck : public ClangTidyCheck {
public:
TrueMacroCheck(StringRef Name, ClangTidyContext *Context)
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 49220fbb39836..51683093e5d23 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -94,7 +94,7 @@ New checks
- New :doc:`bugprone-true-macro
<clang-tidy/checks/bugprone/true-macro>` check.
- FIXME: Write a short description.
+ This check gives a warning if ``true`` is used in the preprocessor when not defined in C.
New check aliases
^^^^^^^^^^^^^^^^^
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
index 70b313774ef15..a5551ed9d9f2c 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
@@ -3,4 +3,18 @@
bugprone-true-macro
===================
-FIXME: Describe what patterns does the check detect and why. Give examples.
+In C++, ``true`` is considered a keyword by the preprocessor so an ``#if true`` enters the true branch,
+while in C, ``true`` is not treated as a special keyword by the preprocessor, so the false branch is entered.
+
+The following snippet returns ``1`` in C++, but ``0`` in C.
+
+.. code-block:: c++
+ int main() {
+ #if true
+ return 1;
+ #else
+ return 0;
+ #endif
+ }
+
+The check also offers fix-it hints.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c
new file mode 100644
index 0000000000000..6495c282f34f4
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c
@@ -0,0 +1,10 @@
+// RUN: %check_clang_tidy -std=c99-or-later %s bugprone-true-macro %t
+
+#if true
+// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+// CHECK-FIXES: 1
+#endif
+
+#if false || true
+// CHECK-MESSAGES: :[[@LINE-1]]:2: warning: in C 'true' in the condition is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+#endif
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
new file mode 100644
index 0000000000000..981a0e84cc241
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
@@ -0,0 +1,5 @@
+// RUN: %check_clang_tidy -std=c99-or-later %s bugprone-true-macro %t
+
+#define FOO true
+// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+// CHECK-FIXES: 1
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c
deleted file mode 100644
index 25ce8b63bb4cd..0000000000000
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro.c
+++ /dev/null
@@ -1,14 +0,0 @@
-// RUN: %check_clang_tidy -std=c99-or-later %s bugprone-true-macro %t
-
-// FIXME: Add something that triggers the check here.
-void f();
-// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: function 'f' is insufficiently awesome [bugprone-true-macro]
-
-// FIXME: Verify the applied fix.
-// * Make the CHECK patterns specific enough and try to make verified lines
-// unique to avoid incorrect matches.
-// * Use {{}} for regular expressions.
-// CHECK-FIXES: {{^}}void awesome_f();{{$}}
-
-// FIXME: Add something that doesn't trigger the check here.
-void awesome_f2();
>From 44a5541f25a2627cd43a3bf4e2e192deff67cc74 Mon Sep 17 00:00:00 2001
From: isuckatcs <65320245+isuckatcs at users.noreply.github.com>
Date: Sat, 22 Feb 2025 11:43:42 +0100
Subject: [PATCH 4/5] fix errors
---
.../bugprone/BugproneTidyModule.cpp | 3 +-
.../clang-tidy/checks/bugprone/true-macro.rst | 4 +-
.../checkers/bugprone/true-macro-condition.c | 10 -----
.../checkers/bugprone/true-macro-defintion.c | 38 +++++++++++++++++++
4 files changed, 42 insertions(+), 13 deletions(-)
delete mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c
diff --git a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
index 2893d7871a710..6d993669f2303 100644
--- a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -248,8 +248,7 @@ class BugproneModule : public ClangTidyModule {
"bugprone-throw-keyword-missing");
CheckFactories.registerCheck<TooSmallLoopVariableCheck>(
"bugprone-too-small-loop-variable");
- CheckFactories.registerCheck<TrueMacroCheck>(
- "bugprone-true-macro");
+ CheckFactories.registerCheck<TrueMacroCheck>("bugprone-true-macro");
CheckFactories.registerCheck<UncheckedOptionalAccessCheck>(
"bugprone-unchecked-optional-access");
CheckFactories.registerCheck<UndefinedMemoryManipulationCheck>(
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
index a5551ed9d9f2c..89ec804130b37 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
@@ -9,6 +9,7 @@ while in C, ``true`` is not treated as a special keyword by the preprocessor, so
The following snippet returns ``1`` in C++, but ``0`` in C.
.. code-block:: c++
+
int main() {
#if true
return 1;
@@ -17,4 +18,5 @@ The following snippet returns ``1`` in C++, but ``0`` in C.
#endif
}
-The check also offers fix-it hints.
+The check identifies such cases, when ``true`` is used without being defined first and also offers fix-its in
+some cases.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c
deleted file mode 100644
index 6495c282f34f4..0000000000000
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-condition.c
+++ /dev/null
@@ -1,10 +0,0 @@
-// RUN: %check_clang_tidy -std=c99-or-later %s bugprone-true-macro %t
-
-#if true
-// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
-// CHECK-FIXES: 1
-#endif
-
-#if false || true
-// CHECK-MESSAGES: :[[@LINE-1]]:2: warning: in C 'true' in the condition is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
-#endif
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
index 981a0e84cc241..060f42c4aee0f 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
@@ -3,3 +3,41 @@
#define FOO true
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
// CHECK-FIXES: 1
+
+#if true
+// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+// CHECK-FIXES: 1
+#endif
+
+#if false || true
+// CHECK-MESSAGES: :[[@LINE-1]]:2: warning: in C 'true' in the condition is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+#endif
+
+#define true 1
+
+#define FOO true
+
+#if true
+#endif
+
+#if false || true
+#endif
+
+#undef true
+
+#define FOO true
+// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+// CHECK-FIXES: 1
+
+#if true
+// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+// CHECK-FIXES: 1
+#endif
+
+#if false || true
+// CHECK-MESSAGES: :[[@LINE-1]]:2: warning: in C 'true' in the condition is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+#endif
+
+#define true true
+// CHECK-MESSAGES: :[[@LINE-1]]:14: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
+// CHECK-FIXES: 1
>From 46af06bac6fad5f0c16aaefec6c32695ebc3b266 Mon Sep 17 00:00:00 2001
From: isuckatcs <65320245+isuckatcs at users.noreply.github.com>
Date: Sun, 23 Feb 2025 00:56:10 +0100
Subject: [PATCH 5/5] addressed comments
---
.../clang-tidy/bugprone/TrueMacroCheck.cpp | 4 ++--
clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h | 10 +++++++---
clang-tools-extra/docs/ReleaseNotes.rst | 7 ++++++-
.../docs/clang-tidy/checks/bugprone/true-macro.rst | 9 +++++----
.../checkers/bugprone/true-macro-defintion.c | 4 +++-
5 files changed, 23 insertions(+), 11 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
index 4b1375db34039..20634f8a460c6 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.cpp
@@ -47,7 +47,7 @@ class MacroCallback : public PPCallbacks {
virtual void If(SourceLocation Loc, SourceRange ConditionRange,
ConditionValueKind ConditionValue) override {
- StringRef Condition =
+ const StringRef Condition =
Lexer::getSourceText(CharSourceRange::getTokenRange(ConditionRange),
PP->getSourceManager(), PP->getLangOpts());
@@ -91,7 +91,7 @@ class MacroCallback : public PPCallbacks {
const char *Str = nullptr;
for (size_t I = 0; I < Condition.size(); ++I) {
- char C = Condition[I];
+ const char C = Condition[I];
if (!Str && Start(C)) {
Str = Condition.begin() + I;
diff --git a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
index 24116dfcbeb4e..f018bb46e0442 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/TrueMacroCheck.h
@@ -13,8 +13,12 @@
namespace clang::tidy::bugprone {
-/// This check gives a warning if `true` is used in the preprocessor when not
-/// defined in C.
+/// In C++, ``true`` is considered a keyword by the preprocessor so an ``#if
+/// true`` enters the true branch, while in C, ``true`` is not treated as a
+/// special keyword by the preprocessor, so the false branch is entered.
+///
+/// The check identifies such cases, when ``true`` is used without being
+/// defined first and also offers fix-its in some cases.
///
/// For the user-facing documentation see:
/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/true-macro.html
@@ -25,7 +29,7 @@ class TrueMacroCheck : public ClangTidyCheck {
void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
Preprocessor *ModuleExpanderPP) override;
bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
- return !LangOpts.CPlusPlus;
+ return LangOpts.C99 || LangOpts.C11 || LangOpts.C17;
}
};
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 51683093e5d23..2bbd62517980e 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -94,7 +94,12 @@ New checks
- New :doc:`bugprone-true-macro
<clang-tidy/checks/bugprone/true-macro>` check.
- This check gives a warning if ``true`` is used in the preprocessor when not defined in C.
+ In C++, ``true`` is considered a keyword by the preprocessor so an ``#if true``
+ enters the true branch, while in C, ``true`` is not treated as a special
+ keyword by the preprocessor, so the false branch is entered.
+
+ The check identifies such cases, when ``true`` is used without being defined
+ first and also offers fix-its in some cases.
New check aliases
^^^^^^^^^^^^^^^^^
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
index 89ec804130b37..6dbe964270dcc 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/true-macro.rst
@@ -3,8 +3,9 @@
bugprone-true-macro
===================
-In C++, ``true`` is considered a keyword by the preprocessor so an ``#if true`` enters the true branch,
-while in C, ``true`` is not treated as a special keyword by the preprocessor, so the false branch is entered.
+In C++, ``true`` is considered a keyword by the preprocessor so an ``#if true``
+enters the true branch, while in C, ``true`` is not treated as a special
+keyword by the preprocessor, so the false branch is entered.
The following snippet returns ``1`` in C++, but ``0`` in C.
@@ -18,5 +19,5 @@ The following snippet returns ``1`` in C++, but ``0`` in C.
#endif
}
-The check identifies such cases, when ``true`` is used without being defined first and also offers fix-its in
-some cases.
+The check identifies such cases, when ``true`` is used without being defined
+first and also offers fix-its in some cases.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
index 060f42c4aee0f..82f2e6eb20cb8 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/true-macro-defintion.c
@@ -1,4 +1,6 @@
-// RUN: %check_clang_tidy -std=c99-or-later %s bugprone-true-macro %t
+// RUN: %check_clang_tidy -std=c99 %s bugprone-true-macro %t
+// RUN: %check_clang_tidy -std=c11 %s bugprone-true-macro %t
+// RUN: %check_clang_tidy -std=c17 %s bugprone-true-macro %t
#define FOO true
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: in C 'true' is treated as an undefined macro and evaluates to a falsy value; consider replacing it with '1' [bugprone-true-macro]
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