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//===- unittests/AST/EvaluateAsRValueTest.cpp -----------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// \file
// \brief Unit tests for evaluation of constant initializers.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Tooling/Tooling.h"
#include "gtest/gtest.h"
#include <map>
#include <string>
using namespace clang::tooling;
namespace {
// For each variable name encountered, whether its initializer was a
// constant.
typedef std::map<std::string, bool> VarInfoMap;
/// \brief Records information on variable initializers to a map.
class EvaluateConstantInitializersVisitor
: public clang::RecursiveASTVisitor<EvaluateConstantInitializersVisitor> {
public:
explicit EvaluateConstantInitializersVisitor(VarInfoMap &VarInfo)
: VarInfo(VarInfo) {}
/// \brief Checks that isConstantInitializer and EvaluateAsRValue agree
/// and don't crash.
///
/// For each VarDecl with an initializer this also records in VarInfo
/// whether the initializer could be evaluated as a constant.
bool VisitVarDecl(const clang::VarDecl *VD) {
if (const clang::Expr *Init = VD->getInit()) {
clang::Expr::EvalResult Result;
bool WasEvaluated = Init->EvaluateAsRValue(Result, VD->getASTContext());
VarInfo[VD->getNameAsString()] = WasEvaluated;
EXPECT_EQ(WasEvaluated, Init->isConstantInitializer(VD->getASTContext(),
false /*ForRef*/));
}
return true;
}
private:
VarInfoMap &VarInfo;
};
class EvaluateConstantInitializersAction : public clang::ASTFrontendAction {
public:
std::unique_ptr<clang::ASTConsumer>
CreateASTConsumer(clang::CompilerInstance &Compiler,
llvm::StringRef FilePath) override {
return std::make_unique<Consumer>();
}
private:
class Consumer : public clang::ASTConsumer {
public:
~Consumer() override {}
void HandleTranslationUnit(clang::ASTContext &Ctx) override {
VarInfoMap VarInfo;
EvaluateConstantInitializersVisitor Evaluator(VarInfo);
Evaluator.TraverseDecl(Ctx.getTranslationUnitDecl());
EXPECT_EQ(2u, VarInfo.size());
EXPECT_FALSE(VarInfo["Dependent"]);
EXPECT_TRUE(VarInfo["Constant"]);
EXPECT_EQ(2u, VarInfo.size());
}
};
};
}
TEST(EvaluateAsRValue, FailsGracefullyForUnknownTypes) {
// This is a regression test; the AST library used to trigger assertion
// failures because it assumed that the type of initializers was always
// known (which is true only after template instantiation).
std::string ModesToTest[] = {"-std=c++03", "-std=c++11", "-std=c++1y"};
for (std::string const &Mode : ModesToTest) {
std::vector<std::string> Args(1, Mode);
Args.push_back("-fno-delayed-template-parsing");
ASSERT_TRUE(runToolOnCodeWithArgs(
std::make_unique<EvaluateConstantInitializersAction>(),
"template <typename T>"
"struct vector {"
" explicit vector(int size);"
"};"
"template <typename R>"
"struct S {"
" vector<R> intervals() const {"
" vector<R> Dependent(2);"
" return Dependent;"
" }"
"};"
"void doSomething() {"
" int Constant = 2 + 2;"
" (void) Constant;"
"}",
Args));
}
}
class CheckLValueToRValueConversionVisitor
: public clang::RecursiveASTVisitor<CheckLValueToRValueConversionVisitor> {
public:
bool VisitDeclRefExpr(const clang::DeclRefExpr *E) {
clang::Expr::EvalResult Result;
E->EvaluateAsRValue(Result, E->getDecl()->getASTContext(), true);
EXPECT_TRUE(Result.Val.hasValue());
// Since EvaluateAsRValue does an implicit lvalue-to-rvalue conversion,
// the result cannot be a LValue.
EXPECT_FALSE(Result.Val.isLValue());
return true;
}
};
class CheckConversionAction : public clang::ASTFrontendAction {
public:
std::unique_ptr<clang::ASTConsumer>
CreateASTConsumer(clang::CompilerInstance &Compiler,
llvm::StringRef FilePath) override {
return std::make_unique<Consumer>();
}
private:
class Consumer : public clang::ASTConsumer {
public:
~Consumer() override {}
void HandleTranslationUnit(clang::ASTContext &Ctx) override {
CheckLValueToRValueConversionVisitor Evaluator;
Evaluator.TraverseDecl(Ctx.getTranslationUnitDecl());
}
};
};
TEST(EvaluateAsRValue, LValueToRValueConversionWorks) {
std::string ModesToTest[] = {"", "-fexperimental-new-constant-interpreter"};
for (std::string const &Mode : ModesToTest) {
std::vector<std::string> Args(1, Mode);
ASSERT_TRUE(runToolOnCodeWithArgs(std::make_unique<CheckConversionAction>(),
"constexpr int a = 20;\n"
"static_assert(a == 20, \"\");\n",
Args));
}
}
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