| /* Compile-time valid expression checker for GDB, the GNU debugger. |
| |
| Copyright (C) 2017-2024 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| /* Helper macros used to build compile-time unit tests that make sure |
| that invalid expressions that should not compile would not compile, |
| and that expressions that should compile do compile, and have the |
| right type. This is mainly used to verify that some utility's API |
| is really as safe as intended. */ |
| |
| #ifndef COMMON_VALID_EXPR_H |
| #define COMMON_VALID_EXPR_H |
| |
| #include "gdbsupport/preprocessor.h" |
| #include "gdbsupport/traits.h" |
| |
| /* Macro that uses SFINAE magic to detect whether the EXPR expression |
| is either valid or ill-formed, at compile time, without actually |
| producing compile-time errors. I.e., check that bad uses of the |
| types (e.g., involving mismatching types) would be caught at |
| compile time. If the expression is valid, also check whether the |
| expression has the right type. |
| |
| EXPR must be defined in terms of some of the template parameters, |
| so that template substitution failure discards the overload instead |
| of causing a real compile error. TYPES is thus the list of types |
| involved in the expression, and TYPENAMES is the same list, but |
| with each element prefixed by "typename". These are passed as |
| template parameter types to the templates within the macro. |
| |
| VALID is a boolean that indicates whether the expression is |
| supposed to be valid or invalid. |
| |
| EXPR_TYPE is the expected type of EXPR. Only meaningful iff VALID |
| is true. If VALID is false, then you must pass "void" as expected |
| type. |
| |
| Each invocation of the macro is wrapped in its own namespace to |
| avoid ODR violations. The generated namespace only includes the |
| line number, so client code should wrap sets of calls in a |
| test-specific namespace too, to fully guarantee uniqueness between |
| the multiple clients in the codebase. */ |
| #define CHECK_VALID_EXPR_INT(TYPENAMES, TYPES, VALID, EXPR_TYPE, EXPR) \ |
| namespace CONCAT (check_valid_expr, __LINE__) { \ |
| \ |
| template <TYPENAMES, typename = decltype (EXPR)> \ |
| struct archetype \ |
| { \ |
| }; \ |
| \ |
| static_assert (gdb::is_detected_exact<archetype<TYPES, EXPR_TYPE>, \ |
| archetype, TYPES>::value == VALID, \ |
| ""); \ |
| } /* namespace */ |
| |
| /* A few convenience macros that support expressions involving a |
| varying numbers of types. If you need more types, feel free to add |
| another variant. */ |
| |
| #define CHECK_VALID_EXPR_1(T1, VALID, EXPR_TYPE, EXPR) \ |
| CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1), \ |
| ESC_PARENS (T1), \ |
| VALID, EXPR_TYPE, EXPR) |
| |
| #define CHECK_VALID_EXPR_2(T1, T2, VALID, EXPR_TYPE, EXPR) \ |
| CHECK_VALID_EXPR_INT (ESC_PARENS(typename T1, typename T2), \ |
| ESC_PARENS (T1, T2), \ |
| VALID, EXPR_TYPE, EXPR) |
| |
| #define CHECK_VALID_EXPR_3(T1, T2, T3, VALID, EXPR_TYPE, EXPR) \ |
| CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, typename T3), \ |
| ESC_PARENS (T1, T2, T3), \ |
| VALID, EXPR_TYPE, EXPR) |
| |
| #define CHECK_VALID_EXPR_4(T1, T2, T3, T4, VALID, EXPR_TYPE, EXPR) \ |
| CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, \ |
| typename T3, typename T4), \ |
| ESC_PARENS (T1, T2, T3, T4), \ |
| VALID, EXPR_TYPE, EXPR) |
| |
| #define CHECK_VALID_EXPR_5(T1, T2, T3, T4, T5, VALID, EXPR_TYPE, EXPR) \ |
| CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, \ |
| typename T3, typename T4, \ |
| typename T5), \ |
| ESC_PARENS (T1, T2, T3, T4, T5), \ |
| VALID, EXPR_TYPE, EXPR) |
| |
| #define CHECK_VALID_EXPR_6(T1, T2, T3, T4, T5, T6, \ |
| VALID, EXPR_TYPE, EXPR) \ |
| CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, \ |
| typename T3, typename T4, \ |
| typename T5, typename T6), \ |
| ESC_PARENS (T1, T2, T3, T4, T5, T6), \ |
| VALID, EXPR_TYPE, EXPR) |
| |
| #endif /* COMMON_VALID_EXPR_H */ |