zytore.blogg.se - Chromium symbol

#Chromium symbol install
#Chromium symbol code

See the symbol files documentation for more details. Crashpad uses the same output format here. build id) as well as all the function names and reduced CFI data from DWARF. We use Google Breakpad currently to generate symbol files (. debug files are used during symbol generation (the next section), and by local developers when using debuggers like gdb.

#Chromium symbol install

all our release builders) will build & install the debug information all the time. Additionally, cros_install_debug_syms can be run manually.īuilders that build from source (e.g. Builders will produce separate binpkgs to help speed things up for developers.īy default, the debug symbols from binpkgs won't be installed locally unless build_packages is run with -withdebugsymbols. The default binpkgs produced locally include the separate debug files in the package's binpkg file. This automatically runs after the ebuild’s src_install phase. The content of /usr/lib/debug/ tree is managed by Portage‘s estrip tool. Objcopy has a -only-keep-debug flag to pull out the debug information into the bug file before we strip it from the bash source. usr/lib/debug/.build-id/xx/yy.debug (where xx/yy are parts of the build-id) is a symlink to e.g. There are also symlinks to easily locate the debug information via build-ids. bin/bash debug information is found at /usr/lib/debug/bin/bug). Typically it matches the path as it exists on the filesystem (e.g. These can be found under the /usr/lib/debug/ tree. Once we've finished linking everything, we create separate debug files (which are often colloquially referred to as “splitdebug”). See the gdb documentation for more details. In the minidump world, this is the same as the module id. This is a unique fingerprint of the program’s loaded code. One critical aspect here is the concept of the executable‘s build-id. This generally covers the src_compile stage of ebuild.

So even if you tweaked debug settings for a specific package, you might have to chase down debug settings in dependencies, as well as the toolchain itself. These are often referred to as C runtime objects and have names like crtn.o.

The toolchain also implicitly links in a few objects directly.

You can see this with glibc‘s libc_nonshared.a, clang’s & gcc's libgcc.a, etc. glibc & clang/gcc) provide a few small static libraries that are always implicitly linked in.

Even if you don‘t think you’re using static libraries, the vast majority of the time you actually are.

In Chromium OS, many packages are only static archives (e.g.

When working with static libraries, many objects might come from other packages via those archives (i.e.

The input objects might not be entirely from the current package.

When we link all the inputs into a single object, we need to gather all that debug information and bundle it in the output. compiler) has to correctly produce DWARF data even in spite of all the optimizations it has to apply. This sounds easy enough (just add -g everywhere), but this can be subtle.

#Chromium symbol code

Compileįirst, we need to compile code with debug information enabled. We don't currently utilize this in Chromium OS. Compressionĭebug information could be compressed at various points in the process. The quality of debugging depends quite a bit on this. The foundation of the system depends on the DWARF format.

Crash servers use symbol files (and other algorithms) to walk the stack and associate addresses with symbols.Crash reports generated & uploaded to crash servers (we don't cover this).Symbol files uploaded to the symbol server backends.Separate debug files processed into symbol files (.gdb) use output ELF & separate debug files when run by developers Debug info split out into separate debug files (e.g.debug files under /usr/lib/debug/).Debug info gathered at link time from inputs (objects, libraries, etc.) into the final output.Debug info generated at compile time in each compilation unit.