mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-25 06:10:14 +01:00
Ivana Ivanovska
b68b6ae1e7
Uses `clang::Parser::ParseConstantExpression()` to parse the macro replacement tokens, added as a token stream to the preprocessor. This extends the support from simple object-like macros with a single replacement token, to multiple tokens like unary operators, binary operators, casting, nested macros etc. The support is still limited to macros that are evaluated to an integer constant. More types to be added as a follow-up. Part of #6303
73 lines
2.4 KiB
C++
73 lines
2.4 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
|
|
// Exceptions. See /LICENSE for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
|
|
#include "toolchain/check/cpp/macros.h"
|
|
|
|
#include "clang/AST/ASTContext.h"
|
|
#include "clang/AST/Expr.h"
|
|
#include "clang/Parse/Parser.h"
|
|
#include "clang/Sema/Sema.h"
|
|
|
|
namespace Carbon::Check {
|
|
|
|
auto TryEvaluateMacroToConstant(Context& context, SemIR::LocId loc_id,
|
|
SemIR::NameId name_id,
|
|
clang::MacroInfo* macro_info) -> clang::Expr* {
|
|
auto name_str_opt = context.names().GetAsStringIfIdentifier(name_id);
|
|
CARBON_CHECK(macro_info, "macro info missing");
|
|
|
|
if (macro_info->getNumTokens() == 0) {
|
|
context.TODO(loc_id, "Unsupported: macro with 0 replacement tokens");
|
|
return nullptr;
|
|
}
|
|
|
|
clang::Sema& sema = context.clang_sema();
|
|
clang::Preprocessor& preprocessor = sema.getPreprocessor();
|
|
clang::Parser parser(preprocessor, sema, false);
|
|
|
|
llvm::SmallVector<clang::Token> tokens(macro_info->tokens().begin(),
|
|
macro_info->tokens().end());
|
|
|
|
clang::Token current_token = parser.getCurToken();
|
|
|
|
// Add eof token
|
|
clang::Token eof;
|
|
eof.startToken();
|
|
eof.setKind(clang::tok::eof);
|
|
eof.setLocation(current_token.getEndLoc());
|
|
tokens.push_back(eof);
|
|
|
|
tokens.push_back(current_token);
|
|
|
|
preprocessor.EnterTokenStream(tokens, false, false);
|
|
parser.ConsumeAnyToken(true);
|
|
|
|
clang::ExprResult result = parser.ParseConstantExpression();
|
|
clang::Expr* result_expr = result.get();
|
|
|
|
bool success =
|
|
!result.isInvalid() && parser.getCurToken().is(clang::tok::eof);
|
|
|
|
if (!success) {
|
|
parser.SkipUntil(clang::tok::eof);
|
|
CARBON_DIAGNOSTIC(
|
|
InCppMacroEvaluation, Error,
|
|
"failed to evaluate macro Cpp.{0} to a valid constant expression",
|
|
std::string);
|
|
context.emitter().Emit(loc_id, InCppMacroEvaluation, (*name_str_opt).str());
|
|
return nullptr;
|
|
}
|
|
|
|
clang::Expr::EvalResult evaluated_result;
|
|
if (!result_expr->EvaluateAsInt(evaluated_result, sema.getASTContext())) {
|
|
context.TODO(loc_id, "non-integer constant expression in macro.");
|
|
return nullptr;
|
|
}
|
|
return clang::IntegerLiteral::Create(
|
|
sema.getASTContext(), evaluated_result.Val.getInt(),
|
|
result_expr->getType(), result_expr->getExprLoc());
|
|
}
|
|
|
|
} // namespace Carbon::Check
|