[msp430-elf] Dwarf line numbers not being encoded properly?

[Orlando Arias]

Greetings,

I am not sure if this is the proper place to ask, but I have been
playing with the msp430-elf port of gcc/binutils/newlib/gdb and I have
been presenting an issue for a while now. Last September, I e-mailed the
GDB mailing list but the message went largely ignored. The bug report I
filed with GDB went ignored as well and remains open. To be honest, I am
not sure if the issue is with GDB, binutils or gcc, but GDB is unable to
read dwarf line numbers from binaries generated by binutils. When asking
about it in the GDB IRC channel, I was told it was because there was
some conflicting information on how these symbols were generated.
readelf is able to correctly identify the symbols because it uses a
different algorithm from GDB when reading them.

I am building the toolchain following the standard build procedure of

binutils -> gcc-stage1 -> newlib -> gcc -> gdb

When building newlib and disassembling some of the files I get this message:

$ msp430-elf-objdump -S /usr/msp430-elf/lib/crtn.o >/dev/null
msp430-elf-objdump: Dwarf Error: Line info data is bigger (0xfffffffc)
than the section (0x43)

which seems to relate to [1], but I ignored it, considering that no
linker script should be utilized to build this kind of thing at the
moment (I believe). Furthermore, gdb is able to read line numbers from
these portions of the executable, it is the main body of the program
where GDB fails to do anything.

I am building the toolchain with pristine sources using:

[binutils]
  ../configure --target=msp430-elf \
    --prefix=/usr \
    --disable-nls \
    --program-prefix=msp430-elf- \
    --enable-multilib \
    --disable-werror \
    --with-sysroot=/usr/msp430-elf \
    --host=${CHOST} \
    --build=${CHOST} \
    --disable-shared \
    --enable-lto

  make configure-host
  make
  make install

[gcc-stage1]
  export CFLAGS_FOR_TARGET="-Os -pipe"
  export CXXFLAGS_FOR_TARGET="-Os -pipe"

  ../configure \
    --prefix=/usr \
    --program-prefix=msp430-elf- \
    --target=msp430-elf \
    --host=$CHOST \
    --build=$CHOST \
    --disable-shared \
    --disable-nls \
    --disable-threads \
    --enable-languages=c \
    --enable-multilib \
    --without-headers \
    --with-newlib \
    --with-local-prefix=/usr/msp430-elf \
    --with-sysroot=/usr/msp430-elf \
    --with-as=/usr/bin/msp430-elf-as \
    --with-ld=/usr/bin/msp430-elf-ld \
    --disable-libgomp

  make all-gcc
  make install-gcc

[newlib]
  export CFLAGS_FOR_TARGET="-Os -g -ffunction-sections -fdata-sections"
  ../configure \
    --prefix=/usr \
    --target=msp430-elf \
    --disable-newlib-supplied-syscalls \
    --enable-newlib-reent-small \
    --disable-newlib-fseek-optimization \
    --disable-newlib-wide-orient \
    --enable-newlib-nano-formatted-io \
    --disable-newlib-io-float \
    --enable-newlib-nano-malloc \
    --disable-newlib-unbuf-stream-opt \
    --enable-lite-exit \
    --enable-newlib-global-atexit \
    --disable-nls

  make -j1
  make install

[gcc]
  export CFLAGS_FOR_TARGET="-Os -pipe"
  export CXXFLAGS_FOR_TARGET="-Os -pipe"

  ../configure \
    --prefix=/usr \
    --program-prefix=msp430-elf- \
    --target=msp430-elf \
    --host=${CHOST} \
    --build=${CHOST} \
    --disable-shared \
    --disable-nls \
    --disable-threads \
    --enable-languages=c,c++ \
    --enable-multilib \
    --with-system-zlib \
    --with-local-prefix=/usr/msp430-elf \
    --with-sysroot=/usr/msp430-elf \
    --with-as=/usr/bin/msp430-elf-as \
    --with-ld=/usr/bin/msp430-elf-ld \
    --disable-libgomp \
    --enable-interwork \
    --enable-addons

  make all-gcc all-target-libgcc
  make install-gcc install-target-libgcc

[gdb]
  ../configure \
    --prefix=/usr \
    --without-guile \
    --target=msp430-elf \
    --host=${CHOST} \
    --build=${CHOST} \
    --with-sysroot=/usr/msp430-elf \
    --disable-nls \
    --with-python=/usr/bin/python2 \
    --with-system-readline \
    --disable-werror \
    --disable-tui

  make
  make install

The GDB bug report can be found at [2] and the original mailing list
message at [3]. I have been told that TI's pre-compiled distribution of
the toolchain can handle line numbers in dwarf data just fine. Is there
a patch am I missing or some parameter am I not passing correctly to the
configure script? Thank you for your time.

Cheers,
Orlando.

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=17940
[2] https://sourceware.org/bugzilla/show_bug.cgi?id=19033
[3] https://sourceware.org/ml/gdb/2015-09/msg00030.html

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