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//===--- AssertSideEffectCheck.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 "AssertSideEffectCheck.h"
#include "../utils/Matchers.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/ASTContext.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 <algorithm>
#include <string>
using namespace clang::ast_matchers;
namespace clang::tidy::bugprone {
namespace {
AST_MATCHER_P2(Expr, hasSideEffect, bool, CheckFunctionCalls,
clang::ast_matchers::internal::Matcher<NamedDecl>,
IgnoredFunctionsMatcher) {
const Expr *E = &Node;
if (const auto *Op = dyn_cast<UnaryOperator>(E)) {
UnaryOperator::Opcode OC = Op->getOpcode();
return OC == UO_PostInc || OC == UO_PostDec || OC == UO_PreInc ||
OC == UO_PreDec;
}
if (const auto *Op = dyn_cast<BinaryOperator>(E)) {
return Op->isAssignmentOp();
}
if (const auto *OpCallExpr = dyn_cast<CXXOperatorCallExpr>(E)) {
if (const auto *MethodDecl =
dyn_cast_or_null<CXXMethodDecl>(OpCallExpr->getDirectCallee()))
if (MethodDecl->isConst())
return false;
OverloadedOperatorKind OpKind = OpCallExpr->getOperator();
return OpKind == OO_Equal || OpKind == OO_PlusEqual ||
OpKind == OO_MinusEqual || OpKind == OO_StarEqual ||
OpKind == OO_SlashEqual || OpKind == OO_AmpEqual ||
OpKind == OO_PipeEqual || OpKind == OO_CaretEqual ||
OpKind == OO_LessLessEqual || OpKind == OO_GreaterGreaterEqual ||
OpKind == OO_LessLess || OpKind == OO_GreaterGreater ||
OpKind == OO_PlusPlus || OpKind == OO_MinusMinus ||
OpKind == OO_PercentEqual || OpKind == OO_New ||
OpKind == OO_Delete || OpKind == OO_Array_New ||
OpKind == OO_Array_Delete;
}
if (const auto *CExpr = dyn_cast<CallExpr>(E)) {
if (!CheckFunctionCalls)
return false;
if (const auto *FuncDecl = CExpr->getDirectCallee()) {
if (FuncDecl->getDeclName().isIdentifier() &&
IgnoredFunctionsMatcher.matches(*FuncDecl, Finder,
Builder)) // exceptions come here
return false;
for (size_t I = 0; I < FuncDecl->getNumParams(); I++) {
const ParmVarDecl *P = FuncDecl->getParamDecl(I);
const Expr *ArgExpr =
I < CExpr->getNumArgs() ? CExpr->getArg(I) : nullptr;
const QualType PT = P->getType().getCanonicalType();
if (ArgExpr && !ArgExpr->isXValue() && PT->isReferenceType() &&
!PT.getNonReferenceType().isConstQualified())
return true;
}
if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
return !MethodDecl->isConst();
}
return true;
}
return isa<CXXNewExpr>(E) || isa<CXXDeleteExpr>(E) || isa<CXXThrowExpr>(E);
}
} // namespace
AssertSideEffectCheck::AssertSideEffectCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
CheckFunctionCalls(Options.get("CheckFunctionCalls", false)),
RawAssertList(Options.get("AssertMacros", "assert,NSAssert,NSCAssert")),
IgnoredFunctions(utils::options::parseListPair(
"__builtin_expect;", Options.get("IgnoredFunctions", ""))) {
StringRef(RawAssertList).split(AssertMacros, ",", -1, false);
}
// The options are explained in AssertSideEffectCheck.h.
void AssertSideEffectCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "CheckFunctionCalls", CheckFunctionCalls);
Options.store(Opts, "AssertMacros", RawAssertList);
Options.store(Opts, "IgnoredFunctions",
utils::options::serializeStringList(IgnoredFunctions));
}
void AssertSideEffectCheck::registerMatchers(MatchFinder *Finder) {
auto IgnoredFunctionsMatcher =
matchers::matchesAnyListedName(IgnoredFunctions);
auto DescendantWithSideEffect =
traverse(TK_AsIs, hasDescendant(expr(hasSideEffect(
CheckFunctionCalls, IgnoredFunctionsMatcher))));
auto ConditionWithSideEffect = hasCondition(DescendantWithSideEffect);
Finder->addMatcher(
stmt(
anyOf(conditionalOperator(ConditionWithSideEffect),
ifStmt(ConditionWithSideEffect),
unaryOperator(hasOperatorName("!"),
hasUnaryOperand(unaryOperator(
hasOperatorName("!"),
hasUnaryOperand(DescendantWithSideEffect))))))
.bind("condStmt"),
this);
}
void AssertSideEffectCheck::check(const MatchFinder::MatchResult &Result) {
const SourceManager &SM = *Result.SourceManager;
const LangOptions LangOpts = getLangOpts();
SourceLocation Loc = Result.Nodes.getNodeAs<Stmt>("condStmt")->getBeginLoc();
StringRef AssertMacroName;
while (Loc.isValid() && Loc.isMacroID()) {
StringRef MacroName = Lexer::getImmediateMacroName(Loc, SM, LangOpts);
Loc = SM.getImmediateMacroCallerLoc(Loc);
// Check if this macro is an assert.
if (llvm::is_contained(AssertMacros, MacroName)) {
AssertMacroName = MacroName;
break;
}
}
if (AssertMacroName.empty())
return;
diag(Loc, "side effect in %0() condition discarded in release builds")
<< AssertMacroName;
}
} // namespace clang::tidy::bugprone
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