llvm/clang/lib/Lex/PPExpressions.cpp

//===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the Preprocessor::EvaluateDirectiveExpression method,
// which parses and evaluates integer constant expressions for #if directives.
//
//===----------------------------------------------------------------------===//
//
// FIXME: implement testing for #assert's.
//
//===----------------------------------------------------------------------===//

#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Lex/CodeCompletionHandler.h"
#include "clang/Lex/LexDiagnostic.h"
#include "clang/Lex/LiteralSupport.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/PPCallbacks.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/Token.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/SaveAndRestore.h"
#include <cassert>

usingnamespaceclang;

namespace {

/// PPValue - Represents the value of a subexpression of a preprocessor
/// conditional and the source range covered by it.
class PPValue { … };

} // end anonymous namespace

static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
                                     Token &PeekTok, bool ValueLive,
                                     bool &IncludedUndefinedIds,
                                     Preprocessor &PP);

/// DefinedTracker - This struct is used while parsing expressions to keep track
/// of whether !defined(X) has been seen.
///
/// With this simple scheme, we handle the basic forms:
///    !defined(X)   and !defined X
/// but we also trivially handle (silly) stuff like:
///    !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)).
struct DefinedTracker { … };

/// EvaluateDefined - Process a 'defined(sym)' expression.
static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
                            bool ValueLive, Preprocessor &PP) { … }

/// EvaluateValue - Evaluate the token PeekTok (and any others needed) and
/// return the computed value in Result.  Return true if there was an error
/// parsing.  This function also returns information about the form of the
/// expression in DT.  See above for information on what DT means.
///
/// If ValueLive is false, then this value is being evaluated in a context where
/// the result is not used.  As such, avoid diagnostics that relate to
/// evaluation.
static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
                          bool ValueLive, Preprocessor &PP) { … }

/// getPrecedence - Return the precedence of the specified binary operator
/// token.  This returns:
///   ~0 - Invalid token.
///   14 -> 3 - various operators.
///    0 - 'eod' or ')'
static unsigned getPrecedence(tok::TokenKind Kind) { … }

static void diagnoseUnexpectedOperator(Preprocessor &PP, PPValue &LHS,
                                       Token &Tok) { … }

/// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is
/// PeekTok, and whose precedence is PeekPrec.  This returns the result in LHS.
///
/// If ValueLive is false, then this value is being evaluated in a context where
/// the result is not used.  As such, avoid diagnostics that relate to
/// evaluation, such as division by zero warnings.
static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
                                     Token &PeekTok, bool ValueLive,
                                     bool &IncludedUndefinedIds,
                                     Preprocessor &PP) { … }

/// EvaluateDirectiveExpression - Evaluate an integer constant expression that
/// may occur after a #if or #elif directive.  If the expression is equivalent
/// to "!defined(X)" return X in IfNDefMacro.
Preprocessor::DirectiveEvalResult
Preprocessor::EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro,
                                          Token &Tok, bool &EvaluatedDefined,
                                          bool CheckForEoD) { … }

Preprocessor::DirectiveEvalResult
Preprocessor::EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro,
                                          bool CheckForEoD) { … }