[cfe-dev] [llvm-dev] Need template help building clang 3.4.2 on OpenVMS so we can bootstrap
Eli Friedman via cfe-dev
cfe-dev at lists.llvm.org
Wed Feb 27 19:14:27 PST 2019
The way it's supposed to work is via template specialization; there's a declaration "struct isa_impl<To, ::clang::DeclContext>" at the bottom of DeclBase.h which is supposed to be used. Not sure why your compiler doesn't like it. Maybe it's instantiating the template before it sees the specialization? Or maybe it's failing to find the specialization when it instantiates the template? Not sure. I guess in that particular context, you could explicitly call Decl::castFromDeclContext, but I'm not sure how many other places would need to be fixed.
Have you considered cross-compiling instead? That seems like less work than porting multiple versions of LLVM to OpenVMS.
-Eli
-----Original Message-----
From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of John Reagan via llvm-dev
Sent: Wednesday, February 27, 2019 1:06 PM
To: cfe-dev at lists.llvm.org; via llvm-dev <llvm-dev at lists.llvm.org>
Subject: [EXT] [llvm-dev] Need template help building clang 3.4.2 on OpenVMS so we can bootstrap
Summary: I need some help building an older clang. I'm getting errors
with casts inside of clang/include/clang/AST/DeclBase.h. I've hit the
limit of my template programming knowledge (not that deep to begin with)
and am looking for workarounds/suggestions. I'm not even sure if it is
the Casting.h support itself or the usage of it inside clang's DeclBase.h
Background: We're porting OpenVMS to x86 using LLVM. Our build
environment is OpenVMS Itanium using an old EDG/Intel C++ compiler
(allegedly C++03). I've been able to build LLVM 3.4.2 just fine (with
only minor tweaks) and we're using that backend with our legacy
frontends. I'm now needing to also build the matching clang 3.4.2 so I
can start the bootstrapping process to get us to a newer version on our
native systems.
Should clang 3.4.2 be buildable by a C++03 compiler like LLVM is?
That's my understanding. Or is it something in LLVM's Support/Casting.h
that only clang exploits?
Any template experts to help me resolve these just so we can bootstrap?
We're looking to use clang/LLVM 3.4.2 to build 3.8.0 as the next step
(we don't have CMake on OpenVMS Itanium due to old C++ compiler)
Thanks for helping!
John
On my first build attempt (we have a bash shell, make, etc. on OpenVMS),
I got errors compiling ParseAST.cpp. Including "incomplete type is not
allowed" and "explicit specialization of class "..." must precede its
first use. Which I resolved with adding an explicit #include
"clang/AST/DeclBase.h" in ParseAST.cpp prior to the other #include's.
Then that yielded
return To::classof(&Val);
...............^
%CXX-E-NOTMEMBER, class "clang::Decl" has no member "classof"
detected during:
instantiation of "bool llvm::iqsa_impl<To, From,
Enabler>::doit(const From &) [with To=clang::Decl,
From=llvm::remove_pointer<llvm::simplify_type<clang::Decl
Context *const>::NonConstSimpleType>::type,
Enabler=void]" at line 98 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa_impl_cl<To, const From
*>::doit(const From *) [with To=clang::Decl,
From=llvm::remove_pointer<llvm::simplify_type<clang::Decl
Context *const>::NonConstSimpleType>::type]" at
line 124
of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa_impl_wrap<To, FromTy,
FromTy>::doit(const FromTy &) [with To=clang::Decl,
FromTy=llvm::simplify_type<clang::DeclContext
*const>::SimpleType]" at line 114 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa_impl_wrap<To, From,
SimpleFrom>::doit(const From &) [with To=clang::Decl,
From=clang::DeclContext *const,
SimpleFrom=llvm::simplify_type<clang::DeclContext
*const>::SimpleType]" at line 135 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa<X,Y>(const Y &) [with
X=clang::Decl, Y=clang::DeclContext *]" at line 239 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "llvm::cast_retty<X, Y *>::ret_type
llvm::cast<X,Y>(Y *) [with X=clang::Decl,
Y=clang::DeclContext]" at line 1064 of
"LLVM$:[REAGAN.llvm-342.tools.clang.include.clang.AST]Dec
lBase.h;1"
at line number 55 in file
LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1
The offending source in DeclBase.h is
/// getParent - Returns the containing DeclContext.
DeclContext *getParent() {
return cast<Decl>(this)->getDeclContext();
-----------^^^^^^^^^^^^
}
const DeclContext *getParent() const {
return const_cast<DeclContext*>(this)->getParent();
}
So I guessed (perhaps wrongly?) that my host compiler wanted to see a
classof() for clang::Decl so I added this to DeclBase.h in Decl's public
section which matches what is done for DeclContext's classof().
static bool classof(const Decl *D) { return true; }
but that ended up with:
return To::classof(&Val);
.......................^
%CXX-E-INCOMPATIBLEPRM, argument of type "const
llvm::remove_pointer<llvm::simplify_type<clang::DeclContext
*const>::NonConstSimpleType>::type *" is incompatible with
parameter
of type "const clang::Decl *"
detected during:
instantiation of "bool llvm::isa_impl<To, From,
Enabler>::doit(const From &) [with To=clang::Decl,
From=llvm::remove_pointer<llvm::simplify_type<clang::Decl
Context *const>::NonConstSimpleType>::type,
Enabler=void]" at line 98 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa_impl_cl<To, const From
*>::doit(const From *) [with To=clang::Decl,
From=llvm::remove_pointer<llvm::simplify_type<clang::Decl
Context *const>::NonConstSimpleType>::type]" at
line 124
of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa_impl_wrap<To, FromTy,
FromTy>::doit(const FromTy &) [with To=clang::Decl,
FromTy=llvm::simplify_type<clang::DeclContext
*const>::SimpleType]" at line 114 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa_impl_wrap<To, From,
SimpleFrom>::doit(const From &) [with To=clang::Decl,
From=clang::DeclContext *const,
SimpleFrom=llvm::simplify_type<clang::DeclContext
*const>::SimpleType]" at line 135 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "bool llvm::isa<X,Y>(const Y &) [with
X=clang::Decl, Y=clang::DeclContext *]" at line 239 of
"LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1"
instantiation of "llvm::cast_retty<X, Y *>::ret_type
llvm::cast<X,Y>(Y *) [with X=clang::Decl,
Y=clang::DeclContext]" at line 1073 of
"LLVM$:[REAGAN.llvm-342.tools.clang.include.clang.AST]Dec
lBase.h;2"
at line number 55 in file
LLVM$:[REAGAN.llvm-342.include.llvm.Support]Casting.h;1
and still lots of other errors of the form
LEAF_TYPE(Enum)
^
%CXX-E-NOCONVERSIONFUN, no suitable conversion function from
"const clang::EnumType" to "const clang::EnumType *" exists
at line number 115 in file
LLVM$:[REAGAN.llvm-342.tools.clang.include.clang.AST]TypeNodes.def;1
and more "incomplete type is not allowed" errors.
And why is there very different form of non-const vs const for things
like getParent() and getLexicalParent()?
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