| Summary: | C asm statement results in C source in assembler listing, even without -ah option | ||
|---|---|---|---|
| Product: | binutils | Reporter: | Paul D. DeRocco <pderocco> |
| Component: | gas | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | nickc |
| Priority: | P2 | ||
| Version: | 2.27 | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | ||
| Attachments: | Files to reproduce bug | ||
The master branch has been updated by Nick Clifton <nickc@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=39865a7f420ab4ca4dec6ed27339618a5d5dc366 commit 39865a7f420ab4ca4dec6ed27339618a5d5dc366 Author: Nick Clifton <nickc@redhat.com> Date: Wed Oct 11 16:48:16 2017 +0100 Disable the inclusion of logical input files in the assembler listing output unless high level source listing has been enabled. PR 21977 * listing.c (listing_newline): Use the name of the current physical input file, rather than the current logical input file, unless including high level source in the listing. * input-scrub.c (as_where_physical): New function. Returns the name of the current physical input file. * as.h: Add prototype for as_where_physical. Hi Paul, Right - I have checked in a small patch to prevent the inclusion of the source file in the listing output unless -ah is used. I have not changed the behaviour when -ah is used however, even though it can produce extravagantly long listings, as you pointed out. I am worried that there are users out there who might rely upon this behaviour, so I did not want to change it. Cheers Nick |
Created attachment 10353 [details] Files to reproduce bug I've attached several files in a Zip file: test-inline.c -- a five-line C program that uses an asm statement. test-inline.sh -- the command line that was generated by Eclipse to compile it. Note it has no -g option, but it explicitly passes -aldg to the assembler, to produce a low-level listing, strip debug output, and show the assembler options. test-inline.S -- the assembly language spat out by the compiler. It only contains the expansion of the asm, but wraps it in #APP and #NO_APP, and a directive indicating what C source line generated it. test-inline.lst -- the assembler listing. foo.txt -- a snippet from a much larger program's assembler listing (see below). Even though -ah isn't passed to the assembler, when it sees #APP, it fetches the C source and inserts it into the listing. Yet it doesn't just show the asm statement, but it shows everything before it back to the beginning of the file, which on a real program can be a lot of junk. Second, while it follows the C source with the expanded asm output (the "addl %edx, %eax"), it puts the hex opcodes on the same line as the C asm statement, not the expansion. It takes some work to make it do that, so whoever wrote that part of the assembler must have thought it was a Good Idea, not an accident. If you look at foo.txt, you can see that when it does this in more complicated cases, which I can't really narrow down to a short test program, it can get confused and put the opcodes before the wrong C source lines. But the more immediate, and probably easier to fix, problem is that with no -ah option, the assembler has no business doing any of this. It looks like the code that handles the #APP comment just assumes that C source should be included, without seeing if -ah was specified. In a big program with a lot of asm statements inside inline functions inside include files, the result is an almost unreadable assembler listing. All I want is a clean listing with no C source. That should be pretty simple.