4 Commits

Author SHA1 Message Date
Takuya Shimizu
491b2810fb [clang][SemaCXX] Diagnose tautological uses of consteval if and is_constant_evaluated
This patch makes clang diagnose extensive cases of consteval if and is_constant_evaluated usage that are tautologically true or false.
This introduces a new IsRuntimeEvaluated boolean flag to Sema::ExpressionEvaluationContextRecord that means the immediate appearance of if consteval or is_constant_evaluated are tautologically false(e.g. inside if !consteval {} block or non-constexpr-qualified function definition body)
This patch also pushes new expression evaluation context when parsing the condition of if constexpr and initializer of constexpr variables so that Sema can be aware that the use of consteval if and is_consteval are tautologically true in if constexpr condition and constexpr variable initializers.
BEFORE this patch, the warning for is_constant_evaluated was emitted from constant evaluator. This patch moves the warning logic to Sema in order to diagnose tautological use of is_constant_evaluated in the same way as consteval if.

This patch separates initializer evaluation context from InitializerScopeRAII.
This fixes a bug that was happening when user takes address of function address in initializers of non-local variables.

Fixes https://github.com/llvm/llvm-project/issues/43760
Fixes https://github.com/llvm/llvm-project/issues/51567

Reviewed By: cor3ntin, ldionne
Differential Revision: https://reviews.llvm.org/D155064
2023-09-27 09:26:06 +09:00
Shafik Yaghmour
67ee18cc7a [Clang] Add machinery to catch overflow in unary minus outside of a constant expression context
We provide several diagnostics for various undefined behaviors due to signed
integer overflow outside of a constant expression context. We were missing the
machinery to catch overflows due to unary minus.

Fixes: https://github.com/llvm/llvm-project/issues/31643

Differential Revision: https://reviews.llvm.org/D142867
2023-01-31 09:35:12 -08:00
Evgeny Shulgin
2bb50a55b0 [clang] Fix time profile in "isIntegerConstantExpr"
The time profiler in `Expr::isIntegerConstantExpr` used to
call `Loc->printToString`, it was inconsistent with other time
profiles in the file and caused segfaults if `Loc` was `nullptr`.

Fixes https://github.com/llvm/llvm-project/issues/58551

Reviewed By: dyung, jloser

Differential Revision: https://reviews.llvm.org/D136549
2022-10-23 23:17:56 +00:00
Evgeny Shulgin
27d8eedd5a [clang] Add time profile for constant evaluation
Add time profiler for various constexpr evaluation events
so that slow event could be visible on the visualized flame chart.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D136022
2022-10-21 23:24:44 +00:00