forked from Imagelibrary/binutils-gdb
6deb7a8185
This commit was inspired by this stackoverflow post: https://stackoverflow.com/questions/73491793/why-is-there-a-%C2%B1-in-lea-rax-rip-%C2%B1-0xeb3 One of the comments helpfully links to this Python test case: from pygments import formatters, lexers, highlight def colorize_disasm(content, gdbarch): try: lexer = lexers.get_lexer_by_name("asm") formatter = formatters.TerminalFormatter() return highlight(content, lexer, formatter).rstrip().encode() except: return None print(colorize_disasm("lea [rip+0x211] # COMMENT", None).decode()) Run the test case and you should see that the '+' character is underlined, and could be confused with a combined +/- symbol. What's happening is that Pygments is failing to parse the input text, and the '+' is actually being marked in the error style. The error style is red and underlined. It is worth noting that the assembly instruction being disassembled here is an x86-64 instruction in the 'intel' disassembly style, rather than the default att style. Clearly the Pygments module expects the att syntax by default. If we change the test case to this: from pygments import formatters, lexers, highlight def colorize_disasm(content, gdbarch): try: lexer = lexers.get_lexer_by_name("asm") lexer.add_filter('raiseonerror') formatter = formatters.TerminalFormatter() return highlight(content, lexer, formatter).rstrip().encode() except: return None res = colorize_disasm("lea rax,[rip+0xeb3] # COMMENT", None) if res: print(res.decode()) else: print("No result!") Here I've added the call: lexer.add_filter('raiseonerror'), and I am now checking to see if the result is None or not. Running this and the test now print 'No result!' - instead of styling the '+' in the error style, we instead give up on the styling attempt. There are two things we need to fix relating to this disassembly text. First, Pygments is expecting att style disassembly, not the intel style that this example uses. Fortunately, Pygments also supports the intel style, all we need to do is use the 'nasm' lexer instead of the 'asm' lexer. However, this leads to the second problem; in our disassembler line we have '# COMMENT'. The "official" Intel disassembler style uses ';' for its comment character, however, gas and libopcodes use '#' as the comment character, as gas uses ';' for an instruction separator. Unfortunately, Pygments expects ';' as the comment character, and treats '#' as an error, which means, with the addition of the 'raiseonerror' filter, that any line containing a '#' comment, will not get styled correctly. However, as the i386 disassembler never produces a '#' character other than for comments, we can easily "fix" Pygments parsing of the disassembly line. This is done by creating a filter. This filter looks for an Error token with the value '#', we then change this into a comment token. Every token after this (until the end of the line) is also converted into a comment. In this commit I do the following: 1. Check the 'disassembly-flavor' setting and select between the 'asm' and 'nasm' lexers based on the setting. If the setting is not available then the 'asm' lexer is used by default, 2. Use "add_filter('raiseonerror')" to ensure that the formatted output will not include any error text, which would be underlined, and might be confusing, 3. If the 'nasm' lexer is selected, then add an additional filter that will format '#' and all other text on the line, as a comment, and 4. If Pygments throws an exception, instead of returning None, return the original, unmodified content. This will mean that this one instruction is printed without styling, but GDB will continue to call into the Python code to style later instructions. I haven't included a test specifically for the above error case, though I have manually check that the above case now styles correctly (with no underline). The existing style tests check that the disassembler styling still works though, so I know I've not generally broken things. One final thought I have after looking at this issue is that I wonder now if using Pygments for styling disassembly from every architecture is actually a good idea? Clearly, the 'asm' lexer is OK with att style x86-64, but not OK with intel style x86-64, so who knows how well it will handle other random architectures? When I first added this feature I tested it against some random RISC-V, ARM, and X86-64 (att style) code, and it seemed fine, but I never tried to make an exhaustive check of all instructions, so its quite possible that there are corner cases where things are styled incorrectly. With the above changes I think that things should be a bit better now. If a particular instruction doesn't parse correctly then our Pygments based styling code will just not style that one instruction. This is combined with the fact that many architectures are now moving to libopcodes based styling, which is much more reliable. So, I think it is fine to keep using Pygments as a fallback mechanism for styling all architectures, even if we know it might not be perfect in all cases.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.