https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85451
Bug ID: 85451
Summary: [offloading] Improve lto-wrapper error message when
not finding mkoffload
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: lto
Assignee: unassigned at gcc dot gnu.org
Reporter: vries at gcc dot gnu.org
CC: marxin at gcc dot gnu.org
Target Milestone: ---
When using an installed host/offloading compiler, you may run into this error
message:
...
$ ./install/bin/x86_64-pc-linux-gnu-gcc -fopenacc test.c
lto-wrapper: fatal error: problem with building target image for nvptx-none
compilation terminated.
/usr/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status
...
This means that mkoffload could not be found.
By providing -B with the path to accel/nvptx-none/mkoffload, we get past the
rror:
...
$ ./install/bin/x86_64-pc-linux-gnu-gcc -fopenacc test.c \
-B $(pwd -P)/install/offload-nvptx-none/libexec/gcc/x86_64-pc-linux-gnu/8.0.1
mkoffload: fatal error: offload compiler
x86_64-pc-linux-gnu-accel-nvptx-none-gcc not found
compilation terminated.
lto-wrapper: fatal error:
/home/vries/oacc/trunk/install/offload-nvptx-none/libexec/gcc/x86_64-pc-linux-gnu/8.0.1//accel/nvptx-none/mkoffload
returned 1 exit status
compilation terminated.
/usr/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status
...
And by providing another -B with the path to
x86_64-pc-linux-gnu-accel-nvptx-none-gcc, we finally succeed:
...
$ ./install/bin/x86_64-pc-linux-gnu-gcc -fopenacc test.c \
-B $(pwd -P)/install/offload-nvptx-none/bin \
-B$(pwd -P)/install/offload-nvptx-none/libexec/gcc/x86_64-pc-linux-gnu/8.0.1
$
...
From the last error message, it's easy to figure out that
x86_64-pc-linux-gnu-accel-nvptx-none-gcc cannot be found (though it doesn't
suggest using -B to fix that).
But from the first error message, it's impossible to know what's going wrong
without stepping with gdb through lto-wrapper.
