diff options
author | Erik Pilkington <erik.pilkington@gmail.com> | 2019-07-02 18:28:13 +0000 |
---|---|---|
committer | Erik Pilkington <erik.pilkington@gmail.com> | 2019-07-02 18:28:13 +0000 |
commit | 159cd770e3ea0c5cba37006c4dc96b3235670f0d (patch) | |
tree | 0f7c041619d7593e111a77c1f79954b83b6dbf99 /lib/Sema/TreeTransform.h | |
parent | 54b8029400637989d16f8467643c46296e62e1d3 (diff) | |
download | clang-159cd770e3ea0c5cba37006c4dc96b3235670f0d.tar.gz |
[C++2a] Add __builtin_bit_cast, used to implement std::bit_cast
This commit adds a new builtin, __builtin_bit_cast(T, v), which performs a
bit_cast from a value v to a type T. This expression can be evaluated at
compile time under specific circumstances.
The compile time evaluation currently doesn't support bit-fields, but I'm
planning on fixing this in a follow up (some of the logic for figuring this out
is in CodeGen). I'm also planning follow-ups for supporting some more esoteric
types that the constexpr evaluator supports, as well as extending
__builtin_memcpy constexpr evaluation to use the same infrastructure.
rdar://44987528
Differential revision: https://reviews.llvm.org/D62825
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@364954 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Sema/TreeTransform.h')
-rw-r--r-- | lib/Sema/TreeTransform.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h index 953889c6a0..7edb2a8d80 100644 --- a/lib/Sema/TreeTransform.h +++ b/lib/Sema/TreeTransform.h @@ -2652,6 +2652,16 @@ public: ListInitialization); } + /// Build a new C++ __builtin_bit_cast expression. + /// + /// By default, performs semantic analysis to build the new expression. + /// Subclasses may override this routine to provide different behavior. + ExprResult RebuildBuiltinBitCastExpr(SourceLocation KWLoc, + TypeSourceInfo *TSI, Expr *Sub, + SourceLocation RParenLoc) { + return getSema().BuildBuiltinBitCastExpr(KWLoc, TSI, Sub, RParenLoc); + } + /// Build a new C++ typeid(type) expression. /// /// By default, performs semantic analysis to build the new expression. @@ -10247,6 +10257,22 @@ TreeTransform<Derived>::TransformCXXNamedCastExpr(CXXNamedCastExpr *E) { template<typename Derived> ExprResult +TreeTransform<Derived>::TransformBuiltinBitCastExpr(BuiltinBitCastExpr *BCE) { + TypeSourceInfo *TSI = + getDerived().TransformType(BCE->getTypeInfoAsWritten()); + if (!TSI) + return ExprError(); + + ExprResult Sub = getDerived().TransformExpr(BCE->getSubExpr()); + if (Sub.isInvalid()) + return ExprError(); + + return getDerived().RebuildBuiltinBitCastExpr(BCE->getBeginLoc(), TSI, + Sub.get(), BCE->getEndLoc()); +} + +template<typename Derived> +ExprResult TreeTransform<Derived>::TransformCXXStaticCastExpr(CXXStaticCastExpr *E) { return getDerived().TransformCXXNamedCastExpr(E); } |