Author: jgorbe
Date: Fri Apr 26 17:32:04 2019
New Revision: 359361
URL: http://llvm.org/viewvc/llvm-project?rev=359361&view=rev
Log:
Revert Fix interactions between __builtin_constant_p and constexpr to match
current trunk GCC.
This reverts r359059 (git commit 0b098754b73f3b96d00ecb1c7605760b11c90298)
Removed:
cfe/trunk/test/SemaCXX/builtin-constant-p.cpp
Modified:
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/lib/Sema/SemaChecking.cpp
cfe/trunk/test/SemaCXX/enable_if.cpp
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=359361&r1=359360&r2=359361&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Fri Apr 26 17:32:04 2019
@@ -7801,33 +7801,19 @@ EvaluateBuiltinClassifyType(const CallEx
}
/// EvaluateBuiltinConstantPForLValue - Determine the result of
-/// __builtin_constant_p when applied to the given pointer.
+/// __builtin_constant_p when applied to the given lvalue.
///
-/// A pointer is only "constant" if it is null (or a pointer cast to integer)
-/// or it points to the first character of a string literal.
-static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) {
- APValue::LValueBase Base = LV.getLValueBase();
- if (Base.isNull()) {
- // A null base is acceptable.
- return true;
- } else if (const Expr *E = Base.dyn_cast<const Expr *>()) {
- if (!isa<StringLiteral>(E))
- return false;
- return LV.getLValueOffset().isZero();
- } else {
- // Any other base is not constant enough for GCC.
- return false;
- }
+/// An lvalue is only "constant" if it is a pointer or reference to the first
+/// character of a string literal.
+template<typename LValue>
+static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) {
+ const Expr *E = LV.getLValueBase().template dyn_cast<const Expr*>();
+ return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero();
}
/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
/// GCC as we can manage.
-static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) {
- // Constant-folding is always enabled for the operand of __builtin_constant_p
- // (even when the enclosing evaluation context otherwise requires a strict
- // language-specific constant expression).
- FoldConstant Fold(Info, true);
-
+static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) {
QualType ArgType = Arg->getType();
// __builtin_constant_p always has one operand. The rules which gcc follows
@@ -7835,27 +7821,34 @@ static bool EvaluateBuiltinConstantP(Eva
//
// - If the operand is of integral, floating, complex or enumeration type,
// and can be folded to a known value of that type, it returns 1.
- // - If the operand can be folded to a pointer to the first character
- // of a string literal (or such a pointer cast to an integral type)
- // or to a null pointer or an integer cast to a pointer, it returns 1.
+ // - If the operand and can be folded to a pointer to the first character
+ // of a string literal (or such a pointer cast to an integral type), it
+ // returns 1.
//
// Otherwise, it returns 0.
//
// FIXME: GCC also intends to return 1 for literals of aggregate types, but
// its support for this does not currently work.
- if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() ||
- ArgType->isAnyComplexType() || ArgType->isPointerType() ||
- ArgType->isNullPtrType()) {
- APValue V;
- if (!::EvaluateAsRValue(Info, Arg, V))
+ if (ArgType->isIntegralOrEnumerationType()) {
+ Expr::EvalResult Result;
+ if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects)
return false;
- // For a pointer (possibly cast to integer), there are special rules.
+ APValue &V = Result.Val;
+ if (V.getKind() == APValue::Int)
+ return true;
if (V.getKind() == APValue::LValue)
return EvaluateBuiltinConstantPForLValue(V);
-
- // Otherwise, any constant value is good enough.
- return V.getKind() != APValue::Uninitialized;
+ } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) {
+ return Arg->isEvaluatable(Ctx);
+ } else if (ArgType->isPointerType() || Arg->isGLValue()) {
+ LValue LV;
+ Expr::EvalStatus Status;
+ EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
+ if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info)
+ : EvaluatePointer(Arg, LV, Info)) &&
+ !Status.HasSideEffects)
+ return EvaluateBuiltinConstantPForLValue(LV);
}
// Anything else isn't considered to be sufficiently constant.
@@ -8266,7 +8259,7 @@ bool IntExprEvaluator::VisitBuiltinCallE
case Builtin::BI__builtin_constant_p: {
auto Arg = E->getArg(0);
- if (EvaluateBuiltinConstantP(Info, Arg))
+ if (EvaluateBuiltinConstantP(Info.Ctx, Arg))
return Success(true, E);
auto ArgTy = Arg->IgnoreImplicit()->getType();
if (!Info.InConstantContext && !Arg->HasSideEffects(Info.Ctx) &&
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=359361&r1=359360&r2=359361&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Fri Apr 26 17:32:04 2019
@@ -1199,14 +1199,10 @@ Sema::CheckBuiltinFunctionCall(FunctionD
if (checkArgCount(*this, TheCall, 1)) return true;
TheCall->setType(Context.IntTy);
break;
- case Builtin::BI__builtin_constant_p: {
+ case Builtin::BI__builtin_constant_p:
if (checkArgCount(*this, TheCall, 1)) return true;
- ExprResult Arg = DefaultFunctionArrayLvalueConversion(TheCall->getArg(0));
- if (Arg.isInvalid()) return true;
- TheCall->setArg(0, Arg.get());
TheCall->setType(Context.IntTy);
break;
- }
case Builtin::BI__builtin_launder:
return SemaBuiltinLaunder(*this, TheCall);
case Builtin::BI__sync_fetch_and_add:
Removed: cfe/trunk/test/SemaCXX/builtin-constant-p.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/builtin-constant-p.cpp?rev=359360&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/builtin-constant-p.cpp (original)
+++ cfe/trunk/test/SemaCXX/builtin-constant-p.cpp (removed)
@@ -1,61 +0,0 @@
-// RUN: %clang_cc1 -std=c++17 -verify %s
-
-using intptr_t = __INTPTR_TYPE__;
-
-// Test interaction of constexpr and __builtin_constant_p.
-
-template<typename T> constexpr bool bcp(T t) {
- return __builtin_constant_p(t);
-}
-template<typename T> constexpr bool bcp_fold(T t) {
- return __builtin_constant_p(((void)(intptr_t)&t, t));
-}
-
-constexpr intptr_t ensure_fold_is_generally_not_enabled = // expected-error
{{constant expression}}
- (intptr_t)&ensure_fold_is_generally_not_enabled; // expected-note {{cast}}
-
-constexpr intptr_t ptr_to_int(const void *p) {
- return __builtin_constant_p(1) ? (intptr_t)p : (intptr_t)p;
-}
-
-constexpr int *int_to_ptr(intptr_t n) {
- return __builtin_constant_p(1) ? (int*)n : (int*)n;
-}
-
-int x;
-
-// Integer and floating point constants encountered during constant expression
-// evaluation are considered constant. So is nullptr_t.
-static_assert(bcp(1));
-static_assert(bcp_fold(1));
-static_assert(bcp(1.0));
-static_assert(bcp_fold(1.0));
-static_assert(bcp(nullptr));
-static_assert(bcp_fold(nullptr));
-
-// Pointers to the start of strings are considered constant.
-static_assert(bcp("foo"));
-static_assert(bcp_fold("foo"));
-
-// Null pointers are considered constant.
-static_assert(bcp<int*>(nullptr));
-static_assert(bcp_fold<int*>(nullptr));
-static_assert(bcp<const char*>(nullptr));
-static_assert(bcp_fold<const char*>(nullptr));
-
-// Other pointers are not.
-static_assert(!bcp(&x));
-static_assert(!bcp_fold(&x));
-
-// Pointers cast to integers follow the rules for pointers.
-static_assert(bcp(ptr_to_int("foo")));
-static_assert(bcp_fold(ptr_to_int("foo")));
-static_assert(!bcp(ptr_to_int(&x)));
-static_assert(!bcp_fold(ptr_to_int(&x)));
-
-// Integers cast to pointers follow the integer rules.
-static_assert(bcp(int_to_ptr(0)));
-static_assert(bcp_fold(int_to_ptr(0)));
-static_assert(bcp(int_to_ptr(123))); // GCC rejects these due to not
recognizing
-static_assert(bcp_fold(int_to_ptr(123))); // the bcp conditional in
'int_to_ptr' ...
-static_assert(__builtin_constant_p((int*)123)); // ... but GCC accepts this
Modified: cfe/trunk/test/SemaCXX/enable_if.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/enable_if.cpp?rev=359361&r1=359360&r2=359361&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/enable_if.cpp (original)
+++ cfe/trunk/test/SemaCXX/enable_if.cpp Fri Apr 26 17:32:04 2019
@@ -522,14 +522,3 @@ void test() {
InConstantContext::foo("abc");
}
} // namespace InConstantContext
-
-namespace StringLiteralDetector {
- void need_string_literal(const char *p)
__attribute__((enable_if(__builtin_constant_p(p), "argument is not a string
literal"))); // expected-note 2{{not a string literal}}
- void test(const char *unknown) {
- need_string_literal("foo");
- need_string_literal(unknown); // expected-error {{no matching function}}
- constexpr char str[] = "bar";
- need_string_literal(str); // expected-error {{no matching function}}
- }
-}
-
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