================ @@ -0,0 +1,70 @@ +//===----------------------------------------------------------------------===// +// +// 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 "RedundantZeroInitializerCheck.h" +#include "clang/AST/Decl.h" +#include "clang/AST/Expr.h" +#include "clang/AST/TypeLoc.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" + +using namespace clang::ast_matchers; + +namespace clang::tidy::modernize { + +namespace { +// Matches an explicitly written ``{<single element>}`` list. ``isExplicit()`` +// excludes compiler-synthesized subobject lists (e.g. from brace elision in a +// multi-dimensional array), which are not written with braces in the source. +AST_MATCHER(InitListExpr, isSingleElementBracedList) { + return Node.isExplicit() && Node.getNumInits() == 1; +} + +// Matches an initializer list inside a macro expansion. +AST_MATCHER(InitListExpr, isInMacro) { + return Node.getBeginLoc().isMacroID() || Node.getEndLoc().isMacroID(); +} + +// Matches a variable whose array bound is deduced from the initializer +// (``T a[] = ...``); replacing ``{0}`` with ``{}`` there would change the size. +AST_MATCHER(VarDecl, hasDeducedArrayBound) { + const TypeSourceInfo *TSI = Node.getTypeSourceInfo(); + if (!TSI) + return false; + const auto ATL = TSI->getTypeLoc().getAs<ArrayTypeLoc>(); + return ATL && !ATL.getSizeExpr(); +} +} // namespace + +void RedundantZeroInitializerCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher( + initListExpr( + hasType(constantArrayType()), isSingleElementBracedList(), + hasInit(0, ignoringParenImpCasts(integerLiteral(equals(0)))), + unless(isInMacro()), + // In a dependent pattern the element type is unknown, so `{}` may not + // be equivalent to `{0}`. An instantiation shares the pattern's + // written braces, so rewriting one could break a sibling. + unless(isInstantiationDependent()), + unless(isInTemplateInstantiation()), + // A deduced array bound (`T a[] = {0}`) would change size under `{}`. + unless(hasParent(varDecl(hasDeducedArrayBound())))) ---------------- zwuis wrote:
```cpp varDecl(hasTypeLoc(/* custom matcher */)) ``` https://github.com/llvm/llvm-project/pull/209367 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
