Linking target code fails when using gold

[pfaffe]

Compiling and linking code using the target directives fails in the final linker step when gold is the linker.

Reproducing example:

int main() {
  double x[n];
  double y[n];

#pragma omp target data map(tofrom : x[0 : n], y[0 : n])
  {
#pragma omp target
#pragma omp for
    for (int i = 0; i < n; i++)
      y[i] += 1.2 * x[i];
  }
}

Clang invokation:
clang-3.8 -fopenmp -omptargets=nvptx64sm_30-nvidia-linux -g -O3 -std=c99 test.c -v

Result:

/usr/bin/ld: error: /tmp/a-192dbd.lk:22:8: syntax error, unexpected STRING
/usr/bin/ld: fatal error: unable to parse script file /tmp/a-192dbd.lk

Where /usr/bin/ld is ld.gold.

[ghost]

Philip,

can you please provide the /tmp/a-192dbd.lk file?
The problem apparently is bfd-gold incompatibility, so we will redirect it.

Sergos

[pfaffe]

Here are the contents of the linker script:

TARGET(binary)
INPUT(/tmp/test-006862.so)
SECTIONS
{
  .openmptgt :
  ALIGN(0x10)
  {
    . = ALIGN(0x10);
    PROVIDE_HIDDEN(__omptgt__img_start_nvptx64sm_30_nvidia_linux = .);
    /tmp/test-006862.so
    PROVIDE_HIDDEN(__omptgt__img_end_nvptx64sm_30_nvidia_linux = .);
  }
  .openmptgt_host_entries :
  ALIGN(0x10)
  SUBALIGN(0x01)
  {
    PROVIDE_HIDDEN(__omptgt__host_entries_begin = .);
    *(.openmptgt_host_entries)
    PROVIDE_HIDDEN(__omptgt__host_entries_end = .);
  }
}
INSERT BEFORE .data

[carlobertolli]

Hi Sergos

I thought that the map Clause was not available yet in any case - can you please confirm?

Thanks

-- Carlo

Sent from my iPhone

On Mar 17, 2016, at 7:50 AM, Sergos [email protected] wrote:

Philip,

can you please provide the /tmp/a-192dbd.lk file?
The problem apparently is bfd-gold incompatibility, so we will redirect it.

Sergos

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[sfantao]

This is a known issue. The embedding of binaries into a fat binary is
controlled by this linker script, but gold does not support the full set of
directives ld does. I investigated this before and was unable to find
something that works well for gold.

The initial design of gold meant to not support any linker scripts. Then
they end up supporting some cases, but "INSERT BEFORE .data" is not one of
them if I remember correctly.

Thanks,
Samuel

From: Philip Pfaffe [email protected]
To: clang-omp/clang_trunk [email protected]
Date: 03/17/2016 07:58 AM
Subject: Re: [clang_trunk] Linking target code fails when using gold
(#30)

Here are the contents of the linker script:

TARGET(binary)
INPUT(/tmp/test-006862.so)
SECTIONS
{
.openmptgt :
ALIGN(0x10)
{
. = ALIGN(0x10);
PROVIDE_HIDDEN(__omptgt__img_start_nvptx64sm_30_nvidia_linux = .);
/tmp/test-006862.so
PROVIDE_HIDDEN(__omptgt__img_end_nvptx64sm_30_nvidia_linux = .);
}
.openmptgt_host_entries :
ALIGN(0x10)
SUBALIGN(0x01)
{
PROVIDE_HIDDEN(__omptgt__host_entries_begin = .);
*(.openmptgt_host_entries)
PROVIDE_HIDDEN(__omptgt__host_entries_end = .);
}
}
INSERT BEFORE .data

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[carlobertolli]

Hi Carlo,

I think this about the github version. Map clause is already there (and
most of the target stuff as well).

Thanks,
Samuel

From: Carlo Bertolli/Watson/IBM
To: "clang-omp/clang_trunk" <reply
+00094b3d268df7aef9403082e9f5d144b5b52d370be84a4792cf0000000113025c1492a169ce086ff069@reply.github.com>
Cc: Samuel F Antao/Watson/IBM@ibmus
Date: 03/17/2016 09:02 AM
Subject: Re: [clang_trunk] Linking target code fails when using gold
(#30)

Hi Sergos

I thought that the map Clause was not available yet in any case - can you
please confirm?

Thanks

-- Carlo

Sent from my iPhone

On Mar 17, 2016, at 7:50 AM, Sergos [email protected] wrote:

  Philip,


  can you please provide the /tmp/a-192dbd.lk file?
  The problem apparently is bfd-gold incompatibility, so we will
  redirect it.


  Sergos


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