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[clang][AST] Widen TypeTraitExprBitfields.NumArgs to 16 bits. 

`32 - 8 - 1 - NumExprBits` is now only equal to 6, which is way too small.
Add a test so that this does not happen again.
This commit is contained in:
Bruno Ricci 2020-06-09 15:10:03 +01:00
parent 6d0f8345ac
commit 8dcc7eecb7
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GPG Key ID: D58C906B2F684D92
3 changed files with 40 additions and 2 deletions
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6
clang/include/clang/AST/Stmt.h
View File

@ -775,8 +775,10 @@ protected:
/// the trait evaluated true or false.
unsigned Value : 1;
/// The number of arguments to this type trait.
unsigned NumArgs : 32 - 8 - 1 - NumExprBits;
/// The number of arguments to this type trait. According to [implimits]
/// 8 bits would be enough, but we require (and test for) at least 16 bits
/// to mirror FunctionType.
unsigned NumArgs;
};
class DependentScopeDeclRefExprBitfields {

4
clang/lib/AST/ExprCXX.cpp
View File

@ -1580,8 +1580,12 @@ TypeTraitExpr::TypeTraitExpr(QualType T, SourceLocation Loc, TypeTrait Kind,
: Expr(TypeTraitExprClass, T, VK_RValue, OK_Ordinary), Loc(Loc),
RParenLoc(RParenLoc) {
TypeTraitExprBits.Kind = Kind;
assert(static_cast<unsigned>(Kind) == TypeTraitExprBits.Kind &&
"TypeTraitExprBits.Kind overflow!");
TypeTraitExprBits.Value = Value;
TypeTraitExprBits.NumArgs = Args.size();
assert(Args.size() == TypeTraitExprBits.NumArgs &&
"TypeTraitExprBits.NumArgs overflow!");
auto **ToArgs = getTrailingObjects<TypeSourceInfo *>();
for (unsigned I = 0, N = Args.size(); I != N; ++I)

32
clang/test/SemaCXX/type-traits.cpp
View File

@ -2829,3 +2829,35 @@ namespace ConstClass {
};
static_assert(!__is_trivially_assignable(B&, const B&), "");
}
namespace type_trait_expr_numargs_overflow {
// Make sure that TypeTraitExpr can store 16 bits worth of arguments.
struct S {
template <typename... Ts> S(Ts... ts) {
static_assert(sizeof...(ts) == 32768+1, "");
}
};
#define T4(X) X,X,X,X
#define T16(X) T4(X),T4(X),T4(X),T4(X)
#define T64(X) T16(X),T16(X),T16(X),T16(X)
#define T256(X) T64(X),T64(X),T64(X),T64(X)
#define T1024(X) T256(X),T256(X),T256(X),T256(X)
#define T4096(X) T1024(X),T1024(X),T1024(X),T1024(X)
#define T16384(X) T4096(X),T4096(X),T4096(X),T4096(X)
#define T32768(X) T16384(X),T16384(X)
void test() {
static_assert(__is_constructible(S, T32768(int), float), "");
}
#undef T4
#undef T16
#undef T64
#undef T256
#undef T1024
#undef T4096
#undef T16384
#undef T32768
} // namespace type_trait_expr_numargs_overflow