Serge_Preis created this revision.
Herald added subscribers: rengolin, aemerson.
This fixes problem described as bug:31405
https://bugs.llvm.org//show_bug.cgi?id=31405
Itanium ABI: debug assertion in template mangling with declype return
The problem is that FunctionTypeDepthState is not properly managed in templated
decltype() construct mangling resulting in assertion inside mangler
mangler: /home/spreis/LLVM/llvm/tools/clang/lib/AST/ItaniumMangle.cpp:3976:
void (anonymous namespace)::CXXNameMangler::mangleFunctionParam(const
clang::ParmVarDecl *): Assertion `parmDepth < FunctionTypeDepth.getDepth()'
failed.
Aborted (core dumped)
for code as simple as `template <typename T> auto foo(T x) -> const
decltype(x);`
The fix is to properly save/restore FunctionTypeDepthState before/after
mangling of type in decltype. This exactly same way FunctionTypeDepthState
treated in other similar places in a mangler.
While in normal operation mangling of non-instantiated templates is not needed,
some tools like source code indexers and others may need this. Also in most
cases mangling of template functions does work, so described assertion looks
like a flaw rather than actual guard.
See issue description above for more details including stack trace of the
issue, reproducer example and simple mangling matcher exhibiting the issue.
https://reviews.llvm.org/D32428
Files:
lib/AST/ItaniumMangle.cpp
Index: lib/AST/ItaniumMangle.cpp
===================================================================
--- lib/AST/ItaniumMangle.cpp
+++ lib/AST/ItaniumMangle.cpp
@@ -4539,9 +4539,11 @@
const FunctionProtoType *Proto =
cast<FunctionProtoType>(FD->getType()->getAs<FunctionType>());
+ FunctionTypeDepthState saved = TrackReturnTypeTags.FunctionTypeDepth.push();
TrackReturnTypeTags.FunctionTypeDepth.enterResultType();
TrackReturnTypeTags.mangleType(Proto->getReturnType());
TrackReturnTypeTags.FunctionTypeDepth.leaveResultType();
+ TrackReturnTypeTags.FunctionTypeDepth.pop(saved);
return TrackReturnTypeTags.AbiTagsRoot.getSortedUniqueUsedAbiTags();
}
Index: lib/AST/ItaniumMangle.cpp
===================================================================
--- lib/AST/ItaniumMangle.cpp
+++ lib/AST/ItaniumMangle.cpp
@@ -4539,9 +4539,11 @@
const FunctionProtoType *Proto =
cast<FunctionProtoType>(FD->getType()->getAs<FunctionType>());
+ FunctionTypeDepthState saved = TrackReturnTypeTags.FunctionTypeDepth.push();
TrackReturnTypeTags.FunctionTypeDepth.enterResultType();
TrackReturnTypeTags.mangleType(Proto->getReturnType());
TrackReturnTypeTags.FunctionTypeDepth.leaveResultType();
+ TrackReturnTypeTags.FunctionTypeDepth.pop(saved);
return TrackReturnTypeTags.AbiTagsRoot.getSortedUniqueUsedAbiTags();
}
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