Details
High Description
hi -
I was seeing a SEGV running genreflex in a build of root 6.06/02 done
with gcc6. I got the crash running
genreflex x.h --selection_file=x.xml -o x_gen.cxx
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with x.h:
#include <map>
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#include <vector>
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typedef std::map<unsigned int, std::vector<const void*> >
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AttrListCVMap;
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void makeIndex()
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{
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std::pair<AttrListCVMap::iterator,bool> res;
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}
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and x.xml:
<lcgdict>
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<class pattern="*iterator<*pair<const*,const*"/>
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</lcgdict>
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I did not reproduce this crash with the builds on lxplus or with a build
with clang.
The crash was in ForwardDeclPrinter::Visit(clang::Decl*) because the pointer
passed in was not actually to a Decl (the first word of the structure
was 0x1, but it should have been a vtable pointer).
#0 0x0000000000a7e491 in clang::Decl::getCanonicalDecl (this=0x3b1d548)
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at /home/sss/root/root-6.06.02/src/root/interpreter/llvm/inst/include/clang/AST/DeclBase.h:712
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#1 0x0000000000b6c24d in cling::ForwardDeclPrinter::getCanonicalOrNamespace (
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this=0x7fffffff9900, D=0x3b1d548)
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at /home/sss/root/root-6.06.02/src/root/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.h:248
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#2 0x0000000000b6456f in cling::ForwardDeclPrinter::Visit (
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this=0x7fffffff9900, D=0x3b1d548)
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at /home/sss/root/root-6.06.02/src/root/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp:115
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#3 0x0000000000b69279 in cling::ForwardDeclPrinter::VisitTemplateName (
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this=0x7fffffff9900, TN=...)
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at /home/sss/root/root-6.06.02/src/root/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp:1125
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#4 0x0000000000b6913c in cling::ForwardDeclPrinter::VisitTemplateArgument (
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this=0x7fffffff9900, TA=...)
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at /home/sss/root/root-6.06.02/src/root/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp:1100
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#5 0x0000000000b68ad2 in cling::ForwardDeclPrinter::VisitClassTemplateSpecializationDecl (this=0x7fffffff9900, D=0x3b1d560)
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at /home/sss/root/root-6.06.02/src/root/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp:989
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I think the problem is actually a couple frames up,
in ForwardDeclPrinter::VisitTemplateArgument, we have:
case clang::TemplateArgument::Template: // intentional fall-through:
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case clang::TemplateArgument::Pack:
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VisitTemplateName(TA.getAsTemplateOrTemplatePattern());
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break;
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The argument here is:
$8 = (const clang::TemplateArgument &) @0x3b1d650: {{DeclArg = {Kind = 8,
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QT = 0x3b1d548, D = 0x321d570}, Integer = {Kind = 8, BitWidth = 1,
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IsUnsigned = 0, {VAL = 61986120, pVal = 0x3b1d548}, Type = 0x321d570},
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Args = {Kind = 8, NumArgs = 1, Args = 0x3b1d548}, TemplateArg = {Kind = 8,
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NumExpansions = 1, Name = 0x3b1d548}, TypeOrValue = {Kind = 8,
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V = 61986120}}}
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Kind==8 is Pack, so we hit this arm of the switch. However,
getAsTemplateOrTemplatePattern is:
TemplateName getAsTemplateOrTemplatePattern() const {
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assert((getKind() == Template || getKind() == TemplateExpansion) &&
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"Unexpected kind");
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return TemplateName::getFromVoidPointer(TemplateArg.Name);
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}
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... so this function cannot be called for a Pack.
(Evidently, assertions get disabled in the build...)
I tried this change, which i'm not at all sure is correct, but gets
genreflex functioning correctly for the cases i'm seeing.
diff --git a/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp b/interpre
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ter/cling/lib/Interpreter/ForwardDeclPrinter.cpp
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index d7a652e..9d4a2fc 100644
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--- a/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp
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+++ b/interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp
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@@ -1096,9 +1096,12 @@ namespace cling {
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Visit(TA.getAsDecl());
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break;
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case clang::TemplateArgument::Template: // intentional fall-through:
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- case clang::TemplateArgument::Pack:
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VisitTemplateName(TA.getAsTemplateOrTemplatePattern());
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break;
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+ case clang::TemplateArgument::Pack:
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+ for (const auto& arg : TA.pack_elements())
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+ VisitTemplateArgument (arg);
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+ break;
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case clang::TemplateArgument::Expression:
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{
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Expr* TAExpr = TA.getAsExpr();
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