nvptx-as reorders ".file" directives

[tschwinge]

While filing https://gcc.gnu.org/PR82202, I noticed that nvptx-as reorders .file directives, for example compiling libgomp/testsuite/libgomp.oacc-c-c++-common/loop-g-1.c with -fopenacc -O2 -foffload=nvptx-none='-save-temps -g' we got:

$ [...]/nvptx-none-as -o ccfEmvMv.s_ ccfEmvMv.s
$ diff -uw ccfEmvMv.s ccfEmvMv.s_
[...]
 // BEGIN FUNCTION DECL: main$_omp_fn$0
 .entry main$_omp_fn$0 (.param.u64 %in_ar0);
-
+.file 1 "source-gcc/libgomp/testsuite/libgomp.oacc-c-c++-common/loop-g-1.c"
 // BEGIN FUNCTION DEF: main$_omp_fn$0
 .entry main$_omp_fn$0 (.param.u64 %in_ar0)
 {
@@ -46,7 +44,6 @@
        @%r54   bra     $L7;
                mov.u64 %r37, %ar0;
                mov.u32 %r36, %ctaid.x;
-       .file 1 "source-gcc/libgomp/testsuite/libgomp.oacc-c-c++-common/loop-g-1.c"
        .loc 1 20 0
                shl.b32 %r39, %r36, 10;
                add.u32 %r40, %r39, %r36;

I don't think this is intentional?

[tschwinge]

This behavior got implemented in commit bd12880 "Deal with .file and .loc directives".

I'll asume that the reason lies in PTX 3.1, 10.5 DEBUGGING DIRECTIVES, Table 162. Debugging Directives: .file stating that "The .file directive is allowed only in the outermost scope".

So, the reordering of .file directives seems to be intentional, after all. But, it needs to be documented properly.