'gcc/testsuite/rust/link/link.exp': Fix 'runtest_file_p' usage

[tschwinge]

The recent commit 418aef1
"Support extern crate" (merged in
commit fd2bd65 "Merge #1362"), added
'gcc/testsuite/rust/link/link.exp', which I understand to be a hacked up
variant of the LTO multi-file testing harness (not reviewed in detail).

Since that commit, there are issues in parallel testing, so that, for example
with:

$ make -j12 check-rust RUNTESTFLAGS='--target_board=unix\{,-m32,-mx32\}'

..., the first variant does test as expected:

@@ -6490,9 +6490,31 @@ PASS: rust/execute/torture/trait9.rs   -Os   at line 13 (test for warnings, line
 PASS: rust/execute/torture/trait9.rs   -Os  (test for excess errors)
 PASS: rust/execute/torture/trait9.rs   -Os  execution test
 PASS: rust/execute/torture/trait9.rs   -Os  output pattern test
+Running /home/thomas/tmp/source/gcc/rust/build/trace-slim/source-gcc/gcc/testsuite/rust/link/link.exp ...
+PASS: rust/link/generic_function_0.rs   -O0  (test for excess errors)
+[...]
+PASS: rust/link/trait_import_0.rs   -Os  (test for excess errors)
                === rust Summary for unix ===

-# of expected passes           6445
+# of expected passes           6466
 # of expected failures         31

..., but we then get undesired changes for the second and following variants:

 Running target unix/-m32
 Running /home/thomas/tmp/source/gcc/rust/build/trace-slim/source-gcc/gcc/testsuite/rust/compile/compile.exp ...
 PASS: rust/compile/abi-options1.rs  at line 2 (test for errors, line 1)
 PASS: rust/compile/abi-options1.rs  at line 7 (test for errors, line 6)
 PASS: rust/compile/abi-options1.rs (test for excess errors)
-PASS: rust/compile/array3.rs  at line 2 (test for warnings, line 1)
-PASS: rust/compile/array3.rs (test for excess errors)
-PASS: rust/compile/array_empty_list.rs  at line 3 (test for errors, line 2)
-PASS: rust/compile/array_empty_list.rs (test for excess errors)
-PASS: rust/compile/arrays1.rs  (test for errors, line 3)
-PASS: rust/compile/arrays1.rs (test for excess errors)
 PASS: rust/compile/arrays2.rs  at line 4 (test for errors, line 3)
 PASS: rust/compile/arrays2.rs (test for excess errors)
 PASS: rust/compile/attr-mismatch-crate-name.rs (test for excess errors)
@@ -8355,110 +8371,215 @@ PASS: rust/compile/torture/generics17.rs   -O3 -g  (test for excess errors)
 PASS: rust/compile/torture/generics17.rs   -Os   at line 18 (test for warnings, line 17)
 PASS: rust/compile/torture/generics17.rs   -Os  (test for excess errors)
 PASS: rust/compile/torture/generics18.rs   -O0   at line 19 (test for warnings, line 18)
+PASS: rust/compile/torture/generics18.rs   -O0   at line 19 (test for warnings, line 18)
+PASS: rust/compile/torture/generics18.rs   -O0   at line 5 (test for warnings, line 4)
 PASS: rust/compile/torture/generics18.rs   -O0   at line 5 (test for warnings, line 4)
 PASS: rust/compile/torture/generics18.rs   -O0  (test for excess errors)
+PASS: rust/compile/torture/generics18.rs   -O0  (test for excess errors)

..., and so on.

This has been determined to be due to repetitive 'runtest_file_p' calls (it's
a mess...), thusly fixed (some would call it a "hack", no doubt), and verified
that, for example:

$ make -j12 check-rust RUNTESTFLAGS='--target_board=unix\{,-m32,-mx32\} link.exp=simple_function_0.rs'

... only runs the one test as indicated.

[philberty]

LGTM, thanks for looking into this for me. I hacked this up and I should really write up what its doing in here.

The idea is that the files named _0.rs are the main files and the _1.rs are compiled to objects first so that it generates crate metadata that the _0.rs file can read this metadata so extern crate works etc.

I feel like this test harness is missing the torture options on compiling the object file and any possible test annotations are ignored also which isn't great. I wasn't able to follow the code from the LTO test harness to actually link the objects together as well.

[philberty]

bors r+

[bors]

Build succeeded:

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