Re: [gomp4] Add tables generation

[Ilya Verbin <iverbin at gmail dot com>]

>+#ifdef ACCEL_COMPILER
>+  /* Decls are placed in reversed order in fat-objects, so we need to
>+     revert them back if we compile target.  */
>...

Actually this change is incorrect.  If host binary is built with -flto, then
both host gcc and target gcc read decls from lto and target_lto sections in the
same order, and resulting tables are identical.
So, in this case there is no need to change the order.

But what if one wants to link non-lto host object files with a target image,
produced from target_lto sections?
In this case the order of host table, produced during ordinary compilation will
differ from the order of target table, produced during lto compilation.

Jakub, what do you think?


Here is a simple example with 4 functions and 4 global variables:

#define N 100

#pragma omp declare target
int arr1[N];
int arr2[N];
int arr3[N];
int arr4[N];
#pragma omp end declare target

void foo ()
{
  #pragma omp target
  for (int i = 0; i < N; i++)
    arr1[i] = 41 + i;

  #pragma omp target
  for (int i = 0; i < N; i++)
    arr2[i] = 42 + i;

  #pragma omp target
  for (int i = 0; i < N; i++)
    arr3[i] = 43 + i;

  #pragma omp target
  for (int i = 0; i < N; i++)
    arr4[i] = 44 + i;
}


I print DECL_NAME ((*v_funcs)[i]) and DECL_NAME ((*v_vars)[i]) in
omp_finish_file:

Host compilation:
$ gcc -std=c99 -fopenmp -flto -c test.c -o test.o

host func 0: foo._omp_fn.0
host func 1: foo._omp_fn.1
host func 2: foo._omp_fn.2
host func 3: foo._omp_fn.3
host var 0:  arr4
host var 1:  arr3
host var 2:  arr2
host var 3:  arr1

Host lto and target lto:
$ gcc -std=c99 -fopenmp -flto test.o -o test

host func 0: foo._omp_fn.3
host func 1: foo._omp_fn.2
host func 2: foo._omp_fn.1
host func 3: foo._omp_fn.0
host var 0:  arr4
host var 1:  arr3
host var 2:  arr2
host var 3:  arr1

target func 0: foo._omp_fn.3
target func 1: foo._omp_fn.2
target func 2: foo._omp_fn.1
target func 3: foo._omp_fn.0
target var 0:  arr4
target var 1:  arr3
target var 2:  arr2
target var 3:  arr1

The func tables produced during ordinary compilation and lto are different.

  -- Ilya