r223852 - AST: Don't assume two zero sized objects live at different addresses
Will Wilson
will at indefiant.com
Thu Dec 11 03:34:03 PST 2014
Hi David,
Looks like r223852 might be responsible for the following failure I just
ran into:
Assertion failed: (D && "Cannot get layout of forward declarations!"),
function getASTRecordLayout, file clang/lib/AST/RecordLayoutBuilder.cpp,
line 2806.
0 clang 0x0000000102d14bee
llvm::sys::PrintStackTrace(__sFILE*) + 46
1 clang 0x0000000102d15f9b
PrintStackTraceSignalHandler(void*) + 27
2 clang 0x0000000102d163e5 SignalHandler(int) + 565
3 libsystem_platform.dylib 0x00007fff8e013f1a _sigtramp + 26
4 clang 0x00000001061d3dff guard variable for
isAllowedIDChar(unsigned int, clang::LangOptions const&)::C99AllowedIDChars
+ 144135
5 clang 0x0000000102d15fcb raise + 27
6 clang 0x0000000102d16082 abort + 18
7 clang 0x0000000102d16061 __assert_rtn + 129
8 clang 0x000000010558eecd
clang::ASTContext::getASTRecordLayout(clang::RecordDecl const*) const + 285
9 clang 0x00000001052345e7
clang::ASTContext::getTypeInfoImpl(clang::Type const*) const + 4951
10 clang 0x00000001052331b5
clang::ASTContext::getTypeInfo(clang::Type const*) const + 165
11 clang 0x00000001052a504c
clang::ASTContext::getTypeInfo(clang::QualType) const + 44
12 clang 0x00000001052acfe5
clang::ASTContext::getTypeSize(clang::QualType) const + 37
*13 clang 0x0000000105519b51 isZeroSized((anonymous
namespace)::LValue const&) + 113*
14 clang 0x00000001054d610e (anonymous
namespace)::IntExprEvaluator::VisitBinaryOperator(clang::BinaryOperator
const*) + 4590
15 clang 0x00000001054d3f08
clang::StmtVisitorBase<clang::make_const_ptr, (anonymous
namespace)::IntExprEvaluator, bool>::VisitBinNE(clang::BinaryOperator
const*) + 40
16 clang 0x00000001054d2240
clang::StmtVisitorBase<clang::make_const_ptr, (anonymous
namespace)::IntExprEvaluator, bool>::Visit(clang::Stmt const*) + 528
17 clang 0x00000001054cc232 Evaluate(clang::APValue&,
(anonymous namespace)::EvalInfo&, clang::Expr const*) + 450
18 clang 0x00000001054c81b1 EvaluateAsRValue((anonymous
namespace)::EvalInfo&, clang::Expr const*, clang::APValue&) + 177
19 clang 0x00000001054c7e1e
clang::Expr::EvaluateAsRValue(clang::Expr::EvalResult&, clang::ASTContext
const&) const + 190
20 clang 0x0000000104844cf3
clang::Sema::VerifyIntegerConstantExpression(clang::Expr*, llvm::APSInt*,
clang::Sema::VerifyICEDiagnoser&, bool) + 931
21 clang 0x00000001048425c8
clang::Sema::VerifyIntegerConstantExpression(clang::Expr*, llvm::APSInt*,
unsigned int, bool) + 120
22 clang 0x0000000104737c01
clang::Sema::BuildStaticAssertDeclaration(clang::SourceLocation,
clang::Expr*, clang::StringLiteral*, clang::SourceLocation, bool) + 369
23 clang 0x0000000104737a74
clang::Sema::ActOnStaticAssertDeclaration(clang::SourceLocation,
clang::Expr*, clang::Expr*, clang::SourceLocation) + 180
24 clang 0x00000001042dcb5c
clang::Parser::ParseStaticAssertDeclaration(clang::SourceLocation&) + 1564
25 clang 0x00000001042c0614
clang::Parser::ParseDeclaration(unsigned int, clang::SourceLocation&,
clang::Parser::ParsedAttributesWithRange&) + 852
26 clang 0x000000010435b003
clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&,
clang::ParsingDeclSpec*) + 2403
27 clang 0x000000010435a655
clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&) +
773
28 clang 0x00000001042b1d8c
clang::ParseAST(clang::Sema&, bool, bool) + 988
29 clang 0x00000001031db9fa
clang::ASTFrontendAction::ExecuteAction() + 522
30 clang 0x00000001037b80d3
clang::CodeGenAction::ExecuteAction() + 3939
31 clang 0x00000001031daf78
clang::FrontendAction::Execute() + 120
32 clang 0x000000010316cbf9
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1017
33 clang 0x000000010324c5f1
clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 3201
34 clang 0x0000000101373930 cc1_main(llvm::ArrayRef<char
const*>, char const*, void*) + 2496
Repro:
struct Foo;
struct Bar
{
static const Foo ms_struct;
};
static_assert(&Bar:: ms_struct != nullptr, "fail");
Will.
On 10 December 2014 at 09:32, David Majnemer <david.majnemer at gmail.com>
wrote:
> Author: majnemer
> Date: Tue Dec 9 17:32:34 2014
> New Revision: 223852
>
> URL: http://llvm.org/viewvc/llvm-project?rev=223852&view=rev
> Log:
> AST: Don't assume two zero sized objects live at different addresses
>
> Zero sized objects may overlap with each other or any other object.
>
> This fixes PR21786.
>
> Modified:
> cfe/trunk/lib/AST/ExprConstant.cpp
> cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
>
> Modified: cfe/trunk/lib/AST/ExprConstant.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=223852&r1=223851&r2=223852&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/AST/ExprConstant.cpp (original)
> +++ cfe/trunk/lib/AST/ExprConstant.cpp Tue Dec 9 17:32:34 2014
> @@ -1422,6 +1422,12 @@ static bool IsWeakLValue(const LValue &V
> return Decl && Decl->isWeak();
> }
>
> +static bool isZeroSized(const LValue &Value) {
> + const ValueDecl *Decl = GetLValueBaseDecl(Value);
> + return Decl && isa<VarDecl>(Decl) &&
> + Decl->getASTContext().getTypeSize(Decl->getType()) == 0;
> +}
> +
> static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
> // A null base expression indicates a null pointer. These are always
> // evaluatable, and they are false unless the offset is zero.
> @@ -6979,6 +6985,10 @@ bool IntExprEvaluator::VisitBinaryOperat
> (RHSValue.Base && RHSValue.Offset.isZero() &&
> isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
> return Error(E);
> + // We can't tell whether an object is at the same address as
> another
> + // zero sized object.
> + if (isZeroSized(LHSValue) || isZeroSized(RHSValue))
> + return Error(E);
> // Pointers with different bases cannot represent the same object.
> // (Note that clang defaults to -fmerge-all-constants, which can
> // lead to inconsistent results for comparisons involving the
> address
>
> Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=223852&r1=223851&r2=223852&view=diff
>
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original)
> +++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Tue Dec 9
> 17:32:34 2014
> @@ -1955,3 +1955,9 @@ namespace EmptyClass {
> constexpr E2 e2b(e2); // expected-error {{constant expression}}
> expected-note{{read of non-const}} expected-note {{in call}}
> constexpr E3 e3b(e3);
> }
> +
> +namespace PR21786 {
> + extern void (*start[])();
> + extern void (*end[])();
> + static_assert(&start != &end, ""); // expected-error {{constant
> expression}}
> +}
>
>
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>
--
*Indefiant *: http://www.indefiant.com
Home of Recode : Runtime C++ Editing for VS
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