[clang-tidy] new cppcoreguidelines-narrowing-conversions check.
Summary:
Checks for narrowing conversions, e.g.
int i = 0;
i += 0.1;
This has what some might consider false positives for:
i += ceil(d);
Reviewers: alexfh, hokein
Subscribers: srhines, nemanjai, mgorny, JDevlieghere, xazax.hun, kbarton
Differential Revision: https://reviews.llvm.org/D38455
llvm-svn: 333066
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
index 2ce1a08..49fedd6 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -4,6 +4,7 @@
AvoidGotoCheck.cpp
CppCoreGuidelinesTidyModule.cpp
InterfacesGlobalInitCheck.cpp
+ NarrowingConversionsCheck.cpp
NoMallocCheck.cpp
OwningMemoryCheck.cpp
ProBoundsArrayToPointerDecayCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
index 51824ec..a039259 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -13,6 +13,7 @@
#include "../misc/UnconventionalAssignOperatorCheck.h"
#include "AvoidGotoCheck.h"
#include "InterfacesGlobalInitCheck.h"
+#include "NarrowingConversionsCheck.h"
#include "NoMallocCheck.h"
#include "OwningMemoryCheck.h"
#include "ProBoundsArrayToPointerDecayCheck.h"
@@ -40,6 +41,8 @@
"cppcoreguidelines-avoid-goto");
CheckFactories.registerCheck<InterfacesGlobalInitCheck>(
"cppcoreguidelines-interfaces-global-init");
+ CheckFactories.registerCheck<NarrowingConversionsCheck>(
+ "cppcoreguidelines-narrowing-conversions");
CheckFactories.registerCheck<NoMallocCheck>("cppcoreguidelines-no-malloc");
CheckFactories.registerCheck<OwningMemoryCheck>(
"cppcoreguidelines-owning-memory");
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
new file mode 100644
index 0000000..2c5676e
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
@@ -0,0 +1,70 @@
+//===--- NarrowingConversionsCheck.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 "NarrowingConversionsCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace cppcoreguidelines {
+
+// FIXME: Check double -> float truncation. Pay attention to casts:
+void NarrowingConversionsCheck::registerMatchers(MatchFinder *Finder) {
+ // ceil() and floor() are guaranteed to return integers, even though the type
+ // is not integral.
+ const auto IsCeilFloorCall = callExpr(callee(functionDecl(
+ hasAnyName("::ceil", "::std::ceil", "::floor", "::std::floor"))));
+
+ const auto IsFloatExpr =
+ expr(hasType(realFloatingPointType()), unless(IsCeilFloorCall));
+
+ // casts:
+ // i = 0.5;
+ // void f(int); f(0.5);
+ Finder->addMatcher(implicitCastExpr(hasImplicitDestinationType(isInteger()),
+ hasSourceExpression(IsFloatExpr),
+ unless(hasParent(castExpr())),
+ unless(isInTemplateInstantiation()))
+ .bind("cast"),
+ this);
+
+ // Binary operators:
+ // i += 0.5;
+ Finder->addMatcher(
+ binaryOperator(isAssignmentOperator(),
+ // The `=` case generates an implicit cast which is covered
+ // by the previous matcher.
+ unless(hasOperatorName("=")),
+ hasLHS(hasType(isInteger())), hasRHS(IsFloatExpr),
+ unless(isInTemplateInstantiation()))
+ .bind("op"),
+ this);
+}
+
+void NarrowingConversionsCheck::check(const MatchFinder::MatchResult &Result) {
+ if (const auto *Op = Result.Nodes.getNodeAs<BinaryOperator>("op")) {
+ if (Op->getLocStart().isMacroID())
+ return;
+ diag(Op->getOperatorLoc(), "narrowing conversion from %0 to %1")
+ << Op->getRHS()->getType() << Op->getLHS()->getType();
+ return;
+ }
+ const auto *Cast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
+ if (Cast->getLocStart().isMacroID())
+ return;
+ diag(Cast->getExprLoc(), "narrowing conversion from %0 to %1")
+ << Cast->getSubExpr()->getType() << Cast->getType();
+}
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
new file mode 100644
index 0000000..35f58bc
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
@@ -0,0 +1,37 @@
+//===--- NarrowingConversionsCheck.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_CPPCOREGUIDELINES_NARROWING_CONVERSIONS_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_NARROWING_CONVERSIONS_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace cppcoreguidelines {
+
+/// Checks for narrowing conversions, e.g:
+/// int i = 0;
+/// i += 0.1;
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-narrowing-conversions.html
+class NarrowingConversionsCheck : public ClangTidyCheck {
+public:
+ NarrowingConversionsCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_NARROWING_CONVERSIONS_H