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//===--- StaticAssertCheck.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 "StaticAssertCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Expr.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include <optional>
#include <string>
using namespace clang::ast_matchers;
namespace clang::tidy::misc {
StaticAssertCheck::StaticAssertCheck(StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context) {}
void StaticAssertCheck::registerMatchers(MatchFinder *Finder) {
auto NegatedString = unaryOperator(
hasOperatorName("!"), hasUnaryOperand(ignoringImpCasts(stringLiteral())));
auto IsAlwaysFalse =
expr(anyOf(cxxBoolLiteral(equals(false)), integerLiteral(equals(0)),
cxxNullPtrLiteralExpr(), gnuNullExpr(), NegatedString))
.bind("isAlwaysFalse");
auto IsAlwaysFalseWithCast = ignoringParenImpCasts(anyOf(
IsAlwaysFalse, cStyleCastExpr(has(ignoringParenImpCasts(IsAlwaysFalse)))
.bind("castExpr")));
auto AssertExprRoot = anyOf(
binaryOperator(
hasAnyOperatorName("&&", "=="),
hasEitherOperand(ignoringImpCasts(stringLiteral().bind("assertMSG"))),
anyOf(binaryOperator(hasEitherOperand(IsAlwaysFalseWithCast)),
anything()))
.bind("assertExprRoot"),
IsAlwaysFalse);
auto NonConstexprFunctionCall =
callExpr(hasDeclaration(functionDecl(unless(isConstexpr()))));
auto AssertCondition =
expr(
anyOf(expr(ignoringParenCasts(anyOf(
AssertExprRoot, unaryOperator(hasUnaryOperand(
ignoringParenCasts(AssertExprRoot)))))),
anything()),
unless(findAll(NonConstexprFunctionCall)))
.bind("condition");
auto Condition =
anyOf(ignoringParenImpCasts(callExpr(
hasDeclaration(functionDecl(hasName("__builtin_expect"))),
hasArgument(0, AssertCondition))),
AssertCondition);
Finder->addMatcher(conditionalOperator(hasCondition(Condition),
unless(isInTemplateInstantiation()))
.bind("condStmt"),
this);
Finder->addMatcher(
ifStmt(hasCondition(Condition), unless(isInTemplateInstantiation()))
.bind("condStmt"),
this);
}
void StaticAssertCheck::check(const MatchFinder::MatchResult &Result) {
const ASTContext *ASTCtx = Result.Context;
const LangOptions &Opts = ASTCtx->getLangOpts();
const SourceManager &SM = ASTCtx->getSourceManager();
const auto *CondStmt = Result.Nodes.getNodeAs<Stmt>("condStmt");
const auto *Condition = Result.Nodes.getNodeAs<Expr>("condition");
const auto *IsAlwaysFalse = Result.Nodes.getNodeAs<Expr>("isAlwaysFalse");
const auto *AssertMSG = Result.Nodes.getNodeAs<StringLiteral>("assertMSG");
const auto *AssertExprRoot =
Result.Nodes.getNodeAs<BinaryOperator>("assertExprRoot");
const auto *CastExpr = Result.Nodes.getNodeAs<CStyleCastExpr>("castExpr");
SourceLocation AssertExpansionLoc = CondStmt->getBeginLoc();
if (!AssertExpansionLoc.isValid() || !AssertExpansionLoc.isMacroID())
return;
StringRef MacroName =
Lexer::getImmediateMacroName(AssertExpansionLoc, SM, Opts);
if (MacroName != "assert" || Condition->isValueDependent() ||
Condition->isTypeDependent() || Condition->isInstantiationDependent() ||
!Condition->isEvaluatable(*ASTCtx))
return;
// False literal is not the result of macro expansion.
if (IsAlwaysFalse && (!CastExpr || CastExpr->getType()->isPointerType())) {
SourceLocation FalseLiteralLoc =
SM.getImmediateSpellingLoc(IsAlwaysFalse->getExprLoc());
if (!FalseLiteralLoc.isMacroID())
return;
StringRef FalseMacroName =
Lexer::getImmediateMacroName(FalseLiteralLoc, SM, Opts);
if (FalseMacroName.compare_insensitive("false") == 0 ||
FalseMacroName.compare_insensitive("null") == 0)
return;
}
SourceLocation AssertLoc = SM.getImmediateMacroCallerLoc(AssertExpansionLoc);
SmallVector<FixItHint, 4> FixItHints;
SourceLocation LastParenLoc;
if (AssertLoc.isValid() && !AssertLoc.isMacroID() &&
(LastParenLoc = getLastParenLoc(ASTCtx, AssertLoc)).isValid()) {
FixItHints.push_back(
FixItHint::CreateReplacement(SourceRange(AssertLoc), "static_assert"));
if (AssertExprRoot) {
FixItHints.push_back(FixItHint::CreateRemoval(
SourceRange(AssertExprRoot->getOperatorLoc())));
FixItHints.push_back(FixItHint::CreateRemoval(
SourceRange(AssertMSG->getBeginLoc(), AssertMSG->getEndLoc())));
FixItHints.push_back(FixItHint::CreateInsertion(
LastParenLoc, (Twine(", \"") + AssertMSG->getString() + "\"").str()));
} else if (!Opts.CPlusPlus17) {
FixItHints.push_back(FixItHint::CreateInsertion(LastParenLoc, ", \"\""));
}
}
diag(AssertLoc, "found assert() that could be replaced by static_assert()")
<< FixItHints;
}
SourceLocation StaticAssertCheck::getLastParenLoc(const ASTContext *ASTCtx,
SourceLocation AssertLoc) {
const LangOptions &Opts = ASTCtx->getLangOpts();
const SourceManager &SM = ASTCtx->getSourceManager();
std::optional<llvm::MemoryBufferRef> Buffer =
SM.getBufferOrNone(SM.getFileID(AssertLoc));
if (!Buffer)
return SourceLocation();
const char *BufferPos = SM.getCharacterData(AssertLoc);
Token Token;
Lexer Lexer(SM.getLocForStartOfFile(SM.getFileID(AssertLoc)), Opts,
Buffer->getBufferStart(), BufferPos, Buffer->getBufferEnd());
// assert first left parenthesis
if (Lexer.LexFromRawLexer(Token) || Lexer.LexFromRawLexer(Token) ||
!Token.is(tok::l_paren))
return SourceLocation();
unsigned int ParenCount = 1;
while (ParenCount && !Lexer.LexFromRawLexer(Token)) {
if (Token.is(tok::l_paren))
++ParenCount;
else if (Token.is(tok::r_paren))
--ParenCount;
}
return Token.getLocation();
}
} // namespace clang::tidy::misc
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