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This is libdwarf README[.md]

Updated 01 May 2022

For release libdwarf-0.4.1

REQUIREMENTS from a libdwarf.tar.xz

Mentioning some that might not be automatically in your base OS release. Restricting attention here to just building libdwarf and dwarfdump.

If the objects you work with do not have compressed-elf-section content zlib/libz are not required for building/using libdwarf/dwarfdump.

Ubuntu: 
sudo apt install pkgconf zlib1g zlib1g-dev
optional add: cmake meson 

FreeBSD:
pkg install bash python3 gmake binutils pkgconf lzlib
optional add: cmake meson

BUILDING from a libdwarf.tar.xz

This is always recommended as it's not necessary to have GNU autotools installed. These examples show doing a build in a directory different than the source as that is generally recommended practice.

GNU configure build

Note: if you get a build failure that mentions something about test/ and missing .Po object files add --disable-dependency-tracking to the configure command.

rm -rf /tmp/build
mkdir /tmp/build
cd /tmp
tar xf <path to>/libdwarf-0.4.0.tar.xz
cd  /tmp/build
/tmp/libdwarf-0.4.0/configure
make
make check

cmake build

README.cmake has details on the available cmake options.

Just like configure, except instead of configure do:

cmake  /tmp/libdwarf-0.4.0
make
ctest -R self

meson build

meson 0.45.1  on Ubuntu 18.04 fails.
meson 0.55.2  on Ubunto 20.04 works.
meson 0.60.3  on Freebsd 12.2 and Freebsd 13.0 works.

For the simplest example:

meson /tmp/libdwarf-0.4.0
ninja -j8

For a faster build with install and sanity tests:

prefx=/tmp/installtargetmeson
export CFLAGS="-g -pipe"
export CXXFLAGS="-g -pipe"
meson /tmp/libdwarf-0.4.0  \
  --prefix=$prefx \
  --default-library shared
ninja -j8 install
ninja test

BUILDING on linux from a git clone of the source tree with configure

This is not recommended as it requires you have GNU autotools and pkg-config installed. Here we assume the source is in a directory named /path/to/code

For example, on Ubuntu 20.04 sudo apt-get install autoconf libtool pkg-config

Note: if you get a build failure that mentions something about test/ and missing .Po object files add --disable-dependency-tracking to the configure command.

Using the source/build directories from above as examples, do :

# Standard Linux Build
cd /path/to/code
sh autogen.sh
cd /tmp/build
/path/to/code/configure
make
make check

BUILDING on MacOS from a git clone of the source tree with configure

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
brew install autoconf automake libtool
# Then use the  Standard Linux Build lines just above.

BUILDING from a git clone of the source tree with cmake

It's always recommended to do cmake builds in a clean directory. See also README.cmake Instead of configure do:

cmake  /path/to/code
make
ctest -R self

Options to configure on Linux/Unix

By default configure compiles and uses libdwarf.a. With --enable-shared appended to the configure step, both libdwarf.a and libdwarf.so are built and the runtimes built will reference libdwarf.so.

If you get a build failure that mentions something about test/ and missing .Po object files add --disable-dependency-tracking to the configure command. With that option do not assume you can alter source files and have make rebuild all necessary. See: https://www.gnu.org/savannah-checkouts/gnu/automake/history/automake-history.html#Dependency-Tracking-Evolution

With --enable-shared --disable-static appended to the configure step, libdwarf.so is built and used; libdwarf.a is not built.

Other options of possible interest:

--enable-wall to turn on compiler diagnostics 
--enable-dwarfexample to compile the example programs.

configure -h     shows the options available.

Sanity checking: gcc has some checks that can be done at runtime. -fsanitize=undefined is turned on by --enable-sanitize

Options to configure on Windows

All libdwarf builds are automatically shared object (dll) builds. No static libdwarf.a is supported.

Distributing

When ready to create a new source distribution do a build and then

make distcheck

INCOMPATIBILITIES. Changes to interfaces

Comparing libdwarf-0.4.0 to libdwarf-0.3.4 A few dealloc() functions changed name to have a consistent pattern for all such. Access to the DWARF5 .debug_names section is now fully implemented.

See the Recent Changes section in libdwarf.pdf (in the release).

Or see the latest online html version for the details..

Notice the table of contents at the right edge of the html page.

Reading DWARF from memory

If one has DWARF bytes in memory or in a kind of file system libdwarf cannot understand one should use

dwarf_object_init_b()
...call libdwarf functions...
dwarf_finish()

and create source to provide functions and data for the three struct types:

struct Dwarf_Obj_Access_Interface_a_s
struct Dwarf_Obj_Access_Methods_a_s
struct Dwarf_Obj_Access_Section_a_s

These functions and structs now seem complete (unlike the earlier libdwarf versions), hence the name and content changes.

For a worked out example of reading DWARF direct from memory with no file system involved see

src/bin/dwarfexample/jitreader.c

David Anderson.