[llvm-bugs] [Bug 27427] New: Segmentation fault during semantic analysis of a nested class that inherits from a template type parameter

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=27427

            Bug ID: 27427
           Summary: Segmentation fault during semantic analysis of a
                    nested class that inherits from a template type
                    parameter
           Product: clang
           Version: trunk
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: C++
          Assignee: unassignedclangbugs at nondot.org
          Reporter: rcraik at ca.ibm.com
                CC: dgregor at apple.com, llvm-bugs at lists.llvm.org
    Classification: Unclassified

With the following testcase:
//t.cpp
template <class T> int f()
{
        struct B : T {
        };

        struct C : virtual T , virtual B {
        };

    return 0;
}


clang hits a segmentation fault:
clang t.cpp
0  clang-3.9 0x0000000013436c60 llvm::sys::PrintStackTrace(llvm::raw_ostream&)
+ 68
1  clang-3.9 0x0000000013437050
2  clang-3.9 0x000000001343516c llvm::sys::RunSignalHandlers() + 180
3  clang-3.9 0x0000000013436514
4            0x00003fffac060478 __kernel_sigtramp_rt64 + 0
5  clang-3.9 0x0000000013a19f64
6  clang-3.9 0x0000000016559cb0
clang::CXXRecordDecl::isDerivedFrom(clang::CXXRecordDecl const*,
clang::CXXBasePaths&) const + 64
7  clang-3.9 0x000000001557d530
clang::Sema::AttachBaseSpecifiers(clang::CXXRecordDecl*,
llvm::MutableArrayRef<clang::CXXBaseSpecifier*>) + 1596
8  clang-3.9 0x000000001557d82c clang::Sema::ActOnBaseSpecifiers(clang::Decl*,
llvm::MutableArrayRef<clang::CXXBaseSpecifier*>) + 168
9  clang-3.9 0x0000000015010b48 clang::Parser::ParseBaseClause(clang::Decl*) +
344
10 clang-3.9 0x00000000150158d4
clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation,
clang::SourceLocation, clang::Parser::ParsedAttributesWithRange&, unsigned int,
clang::Decl*) + 1584
11 clang-3.9 0x000000001501063c
clang::Parser::ParseClassSpecifier(clang::tok::TokenKind,
clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo
const&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext,
clang::Parser::ParsedAttributesWithRange&) + 8296
12 clang-3.9 0x0000000014fefb68
clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&,
clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier,
clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*) + 11680
13 clang-3.9 0x0000000014fe8cfc clang::Parser::ParseSimpleDeclaration(unsigned
int, clang::SourceLocation&, clang::Parser::ParsedAttributesWithRange&, bool,
clang::Parser::ForRangeInit*) + 168
14 clang-3.9 0x0000000014fe8be0 clang::Parser::ParseDeclaration(unsigned int,
clang::SourceLocation&, clang::Parser::ParsedAttributesWithRange&) + 924
15 clang-3.9 0x0000000015076afc
clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*,
32u>&, clang::Parser::AllowedContsructsKind, clang::SourceLocation*,
clang::Parser::ParsedAttributesWithRange&) + 2164
16 clang-3.9 0x0000000015075eb0
clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*,
32u>&, clang::Parser::AllowedContsructsKind, clang::SourceLocation*) + 204
17 clang-3.9 0x0000000015079700 clang::Parser::ParseCompoundStatementBody(bool)
+ 964
18 clang-3.9 0x000000001507cf64
clang::Parser::ParseFunctionStatementBody(clang::Decl*,
clang::Parser::ParseScope&) + 472
19 clang-3.9 0x0000000014fc6554
clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&,
clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) +
3132
20 clang-3.9 0x0000000015087dd8
clang::Parser::ParseSingleDeclarationAfterTemplate(unsigned int,
clang::Parser::ParsedTemplateInfo const&, clang::ParsingDeclRAIIObject&,
clang::SourceLocation&, clang::AccessSpecifier, clang::AttributeList*) + 2188
21 clang-3.9 0x00000000150874e0
clang::Parser::ParseTemplateDeclarationOrSpecialization(unsigned int,
clang::SourceLocation&, clang::AccessSpecifier, clang::AttributeList*) + 1112
22 clang-3.9 0x0000000015087048
clang::Parser::ParseDeclarationStartingWithTemplate(unsigned int,
clang::SourceLocation&, clang::AccessSpecifier, clang::AttributeList*) + 284
23 clang-3.9 0x0000000014fe8a40 clang::Parser::ParseDeclaration(unsigned int,
clang::SourceLocation&, clang::Parser::ParsedAttributesWithRange&) + 508
24 clang-3.9 0x0000000014fc4afc
clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&,
clang::ParsingDeclSpec*) + 3272
25 clang-3.9 0x0000000014fc3dd8
clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&) + 812
26 clang-3.9 0x0000000014fbecd8 clang::ParseAST(clang::Sema&, bool, bool) + 464
27 clang-3.9 0x0000000013dd3dd4 clang::ASTFrontendAction::ExecuteAction() + 468
28 clang-3.9 0x000000001430521c clang::CodeGenAction::ExecuteAction() + 1720
29 clang-3.9 0x0000000013dd36a0 clang::FrontendAction::Execute() + 188
30 clang-3.9 0x0000000013d66f2c
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1304
31 clang-3.9 0x0000000013f51904
clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1692
32 clang-3.9 0x000000001129adc0 cc1_main(llvm::ArrayRef<char const*>, char
const*, void*) + 1156
33 clang-3.9 0x000000001128a68c
34 clang-3.9 0x000000001128b028 main + 1844
35 libc.so.6 0x00003fffaba94580
36 libc.so.6 0x00003fffaba94774 __libc_start_main + 196


This was introduced in r226423 - PR6037, specifically this change in
Sema::AttachBaseSpecifiers:

+      bool found
+        = Class->isDerivedFrom(CanonicalBase->getAsCXXRecordDecl(), Paths);
+      assert(found);

For the given testcase CanonicalBase->getAsCXXRecordDecl() returns null because
CanonicalBase is (at its heart) a TemplateTypeParmType, so a segmentation fault
occurs inside isDerivedFrom when Base is dereferenced.

One workaround for this problem is to continue if CanonicalBase represents a
TemplateTypeParmType

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20160419/68a586d7/attachment-0001.html>