[Bug debug/101987] New: gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[Bug debug/101987] New: gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[dcmay at copper dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101987

            Bug ID: 101987
           Summary: gcc 10.3.1 fails to generate debugging information for
                    aarch64 .S files
           Product: gcc
           Version: 10.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcmay at copper dot net
  Target Milestone: ---

Created attachment 51325
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51325&action=edit
simple makefile project

Using the ARM / linaro aarch64-none-elf build of gcc 10.3.1, building a bare
metal bootloader, (at least) the boot.S entry code is missing all debugging
information. As such, gdb fails to step or honor breakpoints in the startup
code.

linaro's 10.2.1 version generates debugging information as expected; and the
same file compiled with the Ubuntu 20.04 gcc-10.3.0 aarch64 cross compiler
matches exactly (except for AS version number), when viewed using objdump -W.

The problem is trivially reproduced using the attached project, which builds
with missing debug info in target/boot.o using linaro's 10.3.1 cross compiler.

[Bug debug/101987] gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101987

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-08-19
             Status|UNCONFIRMED                 |WAITING

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
GCC seems to be involving as correctly with -g on the trunk:
 ./as --gdwarf2 -v -EL -mabi=lp64 -o /tmp/ccu6moah.o /tmp/ccOieH6c.s


Can you provide the output of "aarch64-none-elf-gcc -v -g boot.S -c"

[Bug debug/101987] gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[dcmay at copper dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101987

--- Comment #2 from Dietmar May <dcmay at copper dot net> ---
$ /opt/linaro/10.3.1/bin/aarch64-none-elf-gcc -v -g src/boot.S -c
Using built-in specs.
COLLECT_GCC=/opt/linaro/10.3.1/bin/aarch64-none-elf-gcc
Target: aarch64-none-elf
Configured with: /data/jenkins/workspace/GNU-toolchain/arm-10/src/gcc/configure
--target=aarch64-none-elf
--prefix=/data/jenkins/workspace/GNU-toolchain/arm-10/build-aarch64-none-elf/install//
--with-gmp=/data/jenkins/workspace/GNU-toolchain/arm-10/build-aarch64-none-elf/host-tools
--with-mpfr=/data/jenkins/workspace/GNU-toolchain/arm-10/build-aarch64-none-elf/host-tools
--with-mpc=/data/jenkins/workspace/GNU-toolchain/arm-10/build-aarch64-none-elf/host-tools
--with-isl=/data/jenkins/workspace/GNU-toolchain/arm-10/build-aarch64-none-elf/host-tools
--disable-shared --disable-nls --disable-threads --disable-tls
--enable-checking=release --enable-languages=c,c++,fortran --with-newlib
--with-pkgversion='GNU Toolchain for the A-profile Architecture 10.3-2021.07
(arm-10.29)' --with-bugurl=https://bugs.linaro.org/
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 10.3.1 20210621 (GNU Toolchain for the A-profile Architecture
10.3-2021.07 (arm-10.29)) 
COLLECT_GCC_OPTIONS='-v' '-g' '-c' '-mlittle-endian' '-mabi=lp64'
 /opt/linaro/10.3.1/bin/../libexec/gcc/aarch64-none-elf/10.3.1/cc1 -E -lang-asm
-quiet -v -iprefix /opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/
src/boot.S -mlittle-endian -mabi=lp64 -g -fworking-directory
-fno-directives-only -o /tmp/ccjOmWwv.s
ignoring nonexistent directory
"/opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/sys-include"
ignoring duplicate directory
"/opt/linaro/10.3.1/bin/../lib/gcc/../../lib/gcc/aarch64-none-elf/10.3.1/include"
ignoring duplicate directory
"/opt/linaro/10.3.1/bin/../lib/gcc/../../lib/gcc/aarch64-none-elf/10.3.1/include-fixed"
ignoring nonexistent directory
"/opt/linaro/10.3.1/bin/../lib/gcc/../../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/sys-include"
ignoring duplicate directory
"/opt/linaro/10.3.1/bin/../lib/gcc/../../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/include"
#include "..." search starts here:
#include <...> search starts here:
 /opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/include
 /opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/include-fixed

/opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-g' '-c' '-mlittle-endian' '-mabi=lp64'

/opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/bin/as
--gdwarf2 -EL -mabi=lp64 -o boot.o /tmp/ccjOmWwv.s
COMPILER_PATH=/opt/linaro/10.3.1/bin/../libexec/gcc/aarch64-none-elf/10.3.1/:/opt/linaro/10.3.1/bin/../libexec/gcc/:/opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/bin/
LIBRARY_PATH=/opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/:/opt/linaro/10.3.1/bin/../lib/gcc/:/opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/lib/
COLLECT_GCC_OPTIONS='-v' '-g' '-c' '-mlittle-endian' '-mabi=lp64'

[Bug debug/101987] gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101987

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |INVALID
             Status|WAITING                     |RESOLVED

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
> /opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/../../../../aarch64-none-elf/bin/as --gdwarf2 -EL -mabi=lp64 -o boot.o /tmp/ccjOmWwv.s

So GCC is doing the right thing; that is passing --gdwarf2 which enables
emitting debug info for the assembly file.  It is either a binutils issue or it
is a bug in your makefile.

You should report this to the Linaro folks anyways since they are the release
of the toolchain.

[Bug debug/101987] gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[dcmay at copper dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101987

Dietmar May <dcmay at copper dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|INVALID                     |FIXED

--- Comment #4 from Dietmar May <dcmay at copper dot net> ---
You're correct.


$ /opt/linaro/10.3.1/bin/../libexec/gcc/aarch64-none-elf/10.3.1/cc1 -E
-lang-asm -quiet -v -iprefix
/opt/linaro/10.3.1/bin/../lib/gcc/aarch64-none-elf/10.3.1/ src/boot.S
-mlittle-endian -mabi=lp64 -g -fworking-directory -fno-directives-only -o tmp.s

preprocesses the .S -> .s for as


$ /opt/linaro/10.2.1/bin/aarch64-none-elf-as --gdwarf2 -EL -mabi=lp64 -o boot.o
tmp.s

yields a .o file with debug info


$ /opt/linaro/10.3.1/bin/aarch64-none-elf-as --gdwarf2 -EL -mabi=lp64 -o boot.o
tmp.s

yields a .o file missing debug info


ergo it's not a gcc issue.

Thanks for helping to diagnose this so quickly.

[Bug debug/101987] gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101987

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|FIXED                       |INVALID

[Bug debug/101987] gcc 10.3.1 fails to generate debugging information for aarch64 .S files

[dcmay at copper dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101987

--- Comment #5 from Dietmar May <dcmay at copper dot net> ---
I've confirmed that the issue is present in binutils 2.36.1, but not 2.35.1

ARM / Linaro's aarch64 10.2.1 toolchain uses binutils 2.35.1
Their 10.3.1 toolchain uses binutils 2.36.1

By copying the 'as' binary from 10.2.1 to the 10.3.1 toolchain, I've confirmed
that the boot.o file contains debugging information, and this problem does not
appear.

In other words, running with gcc 10.3.1, but with the binutils 2.35.1 as
assembler, there is no problem.

I've also confirmed this by assembling using my own mingw build of binutils
2.36.1