llvm dev - Sep 2018 - Function Signature

Hi

I was wondering whether I can extract the function signature from the dwarf
debugging information or symbol table. I mean the argument list and the
return variables.

I know that in dwarf debugging information, a subprogram represents a
function. However, I could not find the information that is related to the
function signature. Any ideas? Many Thanks

Regards
Muhui
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The subprogram DIE provides the return type in DW_AT_type.  Formal parameters
are described using children of the subprogram DIE; note that the
formal_parameter DIEs are required to be in the correct order, but are not
required to be consective (that is, you need to look at all the direct children
of the subprogram DIE).  Also, implicit parameters will be described explicitly
in the DWARF; this includes things like a hidden return-value pointer, or the
'this' pointer for a C++ class method. Implicit parameters ought to have
the DW_AT_artificial flag.

Hope this helps,
--paulr

From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Muhui
Jiang via llvm-dev
Sent: Saturday, September 29, 2018 9:09 AM
To: llvm-dev
Subject: [llvm-dev] Function Signature

Hi

I was wondering whether I can extract the function signature from the dwarf
debugging information or symbol table. I mean the argument list and the return
variables.

I know that in dwarf debugging information, a subprogram represents a function.
However, I could not find the information that is related to the function
signature. Any ideas? Many Thanks

Regards
Muhui
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Also you can just find the DW_TAG_subprogram entry for the interesting
function then look at DW_AT_linkage_name and demangle it.  Although if it's
a C function, this won't work because it's not mangled.  This is easier
than enumerating children recursively, but does not cover all possible use
cases.

On Sat, Sep 29, 2018 at 9:56 AM via llvm-dev <llvm-dev at lists.llvm.org>
wrote:
> The subprogram DIE provides the return type in DW_AT_type.  Formal
> parameters are described using children of the subprogram DIE; note that
> the formal_parameter DIEs are required to be in the correct order, but are
> not required to be consective (that is, you need to look at all the direct
> children of the subprogram DIE).  Also, implicit parameters will be
> described explicitly in the DWARF; this includes things like a hidden
> return-value pointer, or the 'this' pointer for a C++ class method.
> Implicit parameters ought to have the DW_AT_artificial flag.
>
>
>
> Hope this helps,
>
> --paulr
>
>
>
> *From:* llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] *On Behalf Of
*Muhui
> Jiang via llvm-dev
> *Sent:* Saturday, September 29, 2018 9:09 AM
> *To:* llvm-dev
> *Subject:* [llvm-dev] Function Signature
>
>
>
> Hi
>
>
>
> I was wondering whether I can extract the function signature from the
> dwarf debugging information or symbol table. I mean the argument list and
> the return variables.
>
>
>
> I know that in dwarf debugging information, a subprogram represents a
> function. However, I could not find the information that is related to the
> function signature. Any ideas? Many Thanks
>
>
>
> Regards
>
> Muhui
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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