scott.linder added inline comments.
================ Comment at: docs/ClangCommandLineReference.rst:797 + +Generate a section .LLVM.command.line containing the clang driver command line. + ---------------- rjmccall wrote: > 1. Is this section always called `.LLVM.command.line`, or does it differ by > target object-file format? > 2. For that matter, is this actually supported by all object-file formats? > 3. Please describe the format of the section. Is it just a flat C string? > Is it nul-terminated? Are different options combined with spaces, and if so, > does that mean that interior spaces in command line arguments are impossible > to distinguish? If the latter, I assume that this is required behavior for > backward compatibility; please at least apologize for that in the > documentation. :) For (1) I think the answer should be that we emit `.LLVM.command.line` (or whatever name we land on) for every object-file format with the concept of names for sections. For (2), I have only implemented this for ELF so far in LLVM. I don't know how reasonable that is, and if it isn't I can look at adding it to other common object-file formats that LLVM supports. For (3), my current proposal for the format is the same as the `.comment` section for idents: null-surrounded strings. Interior spaces are escaped, in the same manner as for the -g variant. There may still be more thought to put into the format, as the GCC version null-terminates each individual option; the reason I avoided this is that during object linking the options of many command-lines simply get mixed together, which seems less than useful. As an example, for ELF `clang -frecord-command-line -S "foo .c"` produces the ASM: ``` .section .LLVM.command.line,"MS",@progbits,1 .zero 1 .ascii "/usr/local/bin/clang-8 -frecord-command-line -S foo\\ .c" .zero 1 ``` And for multiple command-lines in a single object (e.g. linking three objects with recorded command-lines) this would be: ``` .section .LLVM.command.line,"MS",@progbits,1 .zero 1 .ascii "/usr/local/bin/clang-8 -frecord-command-line -c foo\\ .c" .zero 1 .ascii "/usr/local/bin/clang-8 -frecord-command-line -some -unique -options -c bar.c" .zero 1 .ascii "/usr/local/bin/clang-8 -frecord-command-line -something -else -c baz.c" .zero 1 ``` I will try to capture more of this in the documentation. https://reviews.llvm.org/D54489 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
