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Reply-To: noloader@gmail.com
From: Jeffrey Walton <noloader@gmail.com>
Date: Tue, 20 Apr 2021 12:39:26 -0400
Message-ID: <CAH8yC8=5f2vbP4NtHs6Zt2tTQnJG60z2Pdbep4QZ404iiQvr4w@mail.gmail.com>
Subject: Re: Best reference for understanding ELF format
To: Peng Yu <pengyu.ut@gmail.com>
Cc: libc-help <libc-help@sourceware.org>
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On Tue, Apr 20, 2021 at 12:29 PM Peng Yu via Libc-help
<libc-help@sourceware.org> wrote:
> ...
> People don't usually directly call ld to generate object, executable
> or shared library files.
>
> Instead, gcc/clang are called. So there is nothing wrong to say those
> files are produced by gcc/clang, at least at a superficially level.
> You can say that gcc/clang don't directly produce the ELF files.
> Nevertheless, this doesn't add too much to the topic of this thread.

I think Clang can produce object files directly. Clang has an
integrated assembler.

On OS X, sometimes you need to use -Wa,-q to enlist the Clang
Integrated Assembler because GNU toolchain is too old to consume code
for some ISA's, like AVX and AVX2. (That's assuming you're using a
modern GCC, like from Macports or Homebrew). That's why -Wa,-q shows
up in places like
https://github.com/weidai11/cryptopp/blob/master/GNUmakefile#L109.

Jeff