Re: [PATCH][gdb/testsuite] Fix gdb.cp/step-and-next-inline.exp with gcc-11

Bernd Edlinger
2021-07-21T14:14:24Z

On 7/21/21 10:31 AM, Tom de Vries wrote:
> Hi,
>
> When running test-case gdb.cp/step-and-next-inline.exp with gcc-11, I run
> into:
> ...
> KPASS: gdb.cp/step-and-next-inline.exp: no_header: next step 1 \
> (PRMS symtab/25507)
> FAIL: gdb.cp/step-and-next-inline.exp: no_header: next step 2
> KPASS: gdb.cp/step-and-next-inline.exp: no_header: next step 3 \
> (PRMS symtab/25507)
> ...
>
> [ Note that I get the same result with gcc-11 and target board
> unix/gdb:debug_flags=-gdwarf-4, so this is not a dwarf 4 vs 5 issue. ]
>
> With gcc-10, I have this trace:
> ...
> 64 get_alias_set (&xx);
> get_alias_set (t=0x601038 <xx>) at step-and-next-inline.cc:51
> 51 if (t != NULL
> 40 if (t->x != i)
> 52 && TREE_TYPE (t).z != 1
> 43 return x;
> 53 && TREE_TYPE (t).z != 2
> 43 return x;
> 54 && TREE_TYPE (t).z != 3)
> 43 return x;
> main () at step-and-next-inline.cc:65
> 65 return 0;
> ...
> and with gcc-11, I have instead:
> ...
> 64 get_alias_set (&xx);
> get_alias_set (t=0x601038 <xx>) at step-and-next-inline.cc:51
> 51 if (t != NULL
> 52 && TREE_TYPE (t).z != 1
> 43 return x;
> 53 && TREE_TYPE (t).z != 2
> 43 return x;
> 54 && TREE_TYPE (t).z != 3)
> 43 return x;
> main () at step-and-next-inline.cc:65
> 65 return 0;
> ...
> and with clang-10, I have instead:
> ...
> 64 get_alias_set (&xx);
> get_alias_set (t=0x601034 <xx>) at step-and-next-inline.cc:51
> 51 if (t != NULL
> 52 && TREE_TYPE (t).z != 1
> 53 && TREE_TYPE (t).z != 2
> 54 && TREE_TYPE (t).z != 3)
> 51 if (t != NULL
> 57 }
> main () at step-and-next-inline.cc:65
> 65 return 0;
> ...
>
> The test-case tries to verify that we don't step into inlined function
> tree_check (lines 40-43) (so, with the clang trace we get that right).
>
> The test-case then tries to kfail the problems when using gcc, but this is
> done in such a way that the testing still gets out of sync after a failure.
> That is: the "next step 2" check that is supposed to match
> "TREE_TYPE (t).z != 2" is actually matching "TREE_TYPE (t).z != 1":
> ...
> (gdb) next^M
> 52 && TREE_TYPE (t).z != 1^M
> (gdb) PASS: gdb.cp/step-and-next-inline.exp: no_header: next step 2
> ...
>
> Fix this by issuing extra nexts to arrive at the required lines.
>
> Tested on x86_64-linux, with gcc-8, gcc-9, gcc-10, gcc-11, clang-8, clang-10
> and clang-12.
>
> Any comments?
>

Note that I've posted a patch series that would fix this test case for all
gcc/clang versions I've tested, although I admit I've tested fewer versions than you.

* Improve debugging of optimized code
https://sourceware.org/pipermail/gdb-patches/2021-January/175617.html

(2021-05-31) v2 posted at:
[0/4] https://sourceware.org/pipermail/gdb-patches/2021-May/179367.html
[1/4] https://sourceware.org/pipermail/gdb-patches/2021-May/179368.html
[2/4] https://sourceware.org/pipermail/gdb-patches/2021-May/179370.html
[3/4] https://sourceware.org/pipermail/gdb-patches/2021-May/179369.html

Thanks
Bernd.

> Thanks,
> - Tom
>
> [gdb/testsuite] Fix gdb.cp/step-and-next-inline.exp with gcc-11
>
> gdb/testsuite/ChangeLog:
>
> 2021-07-20 Tom de Vries <tdevries@suse.de>
>
> * gdb.cp/step-and-next-inline.cc (tree_check, get_alias_set, main):
> Tag closing brace with comment.
> * gdb.cp/step-and-next-inline.h: Update to keep identical with
> step-and-next-inline.cc.
> * gdb.cp/step-and-next-inline.exp: Issue extra next when required.
>
> ---
> gdb/testsuite/gdb.cp/step-and-next-inline.cc | 6 +-
> gdb/testsuite/gdb.cp/step-and-next-inline.exp | 89 ++++++++++++++++++++++++---
> gdb/testsuite/gdb.cp/step-and-next-inline.h | 2 +-
> 3 files changed, 84 insertions(+), 13 deletions(-)
>
> diff --git a/gdb/testsuite/gdb.cp/step-and-next-inline.cc b/gdb/testsuite/gdb.cp/step-and-next-inline.cc
> index 6f0a7fbda9e..26b29d01777 100644
> --- a/gdb/testsuite/gdb.cp/step-and-next-inline.cc
> +++ b/gdb/testsuite/gdb.cp/step-and-next-inline.cc
> @@ -41,7 +41,7 @@ tree_check (tree *t, int i)
> abort();
> tree *x = t;
> return x;
> -}
> +} // tree-check
>
> #endif /* USE_NEXT_INLINE_H */
>
> @@ -54,7 +54,7 @@ get_alias_set (tree *t)
> && TREE_TYPE (t).z != 3)
> return 0;
> return 1;
> -}
> +} // get_alias_set
>
> tree xx;
>
> @@ -63,4 +63,4 @@ main()
> {
> get_alias_set (&xx);
> return 0;
> -}
> +} // main
> diff --git a/gdb/testsuite/gdb.cp/step-and-next-inline.exp b/gdb/testsuite/gdb.cp/step-and-next-inline.exp
> index 85f7b8d5af1..13d801bb539 100644
> --- a/gdb/testsuite/gdb.cp/step-and-next-inline.exp
> +++ b/gdb/testsuite/gdb.cp/step-and-next-inline.exp
> @@ -67,29 +67,100 @@ proc do_test { use_header } {
> gdb_test "step" ".*" "step into get_alias_set"
> gdb_test "bt" "\\s*\\#0\\s+get_alias_set\[^\r\]*${srcfile}:.*" \
> "not in inline 1"
> +
> # It's possible that this first failure (when not using a header
> # file) is GCC's fault, though the remaining failures would best
> # be fixed by adding location views support (though it could be
> # that some easier heuristic could be figured out). Still, it is
> # not certain that the first failure wouldn't also be fixed by
> # having location view support, so for now it is tagged as such.
> - if {[test_compiler_info gcc*] && !$use_header} {
> - setup_kfail "*-*-*" symtab/25507
> + set have_kfail [expr [test_compiler_info gcc*] && !$use_header]
> +
> + set ok 1
> + gdb_test_multiple "next" "next step 1" {
> + -re -wrap "if \\(t->x != i\\)" {
> + set ok 0
> + send_gdb "next\n"
> + exp_continue
> + }
> + -re -wrap ".*TREE_TYPE.* != 1" {
> + if { $ok } {
> + pass $gdb_test_name
> + } else {
> + if { $have_kfail } {
> + setup_kfail "*-*-*" symtab/25507
> + }
> + fail $gdb_test_name
> + }
> + }
> }
> - gdb_test "next" ".*TREE_TYPE.*" "next step 1"
> gdb_test "bt" "\\s*\\#0\\s+get_alias_set\[^\r\]*${srcfile}:.*" \
> "not in inline 2"
> - gdb_test "next" ".*TREE_TYPE.*" "next step 2"
> +
> + set ok 1
> + gdb_test_multiple "next" "next step 2" {
> + -re -wrap "return x;" {
> + set ok 0
> + send_gdb "next\n"
> + exp_continue
> + }
> + -re -wrap ".*TREE_TYPE.* != 2" {
> + if { $ok } {
> + pass $gdb_test_name
> + } else {
> + if { $have_kfail } {
> + setup_kfail "*-*-*" symtab/25507
> + }
> + fail $gdb_test_name
> + }
> + }
> + }
> gdb_test "bt" "\\s*\\#0\\s+get_alias_set\[^\r\]*${srcfile}:.*" \
> "not in inline 3"
> - if {[test_compiler_info gcc*] && !$use_header} {
> - setup_kfail "*-*-*" symtab/25507
> +
> + set ok 1
> + gdb_test_multiple "next" "next step 3" {
> + -re -wrap "return x;" {
> + set ok 0
> + send_gdb "next\n"
> + exp_continue
> + }
> + -re -wrap ".*TREE_TYPE.* != 3\\)" {
> + if { $ok } {
> + pass $gdb_test_name
> + } else {
> + if { $have_kfail } {
> + setup_kfail "*-*-*" symtab/25507
> + }
> + fail $gdb_test_name
> + }
> + }
> }
> - gdb_test "next" ".*TREE_TYPE.*" "next step 3"
> gdb_test "bt" "\\s*\\#0\\s+get_alias_set\[^\r\]*${srcfile}:.*" \
> "not in inline 4"
> - if {!$use_header} { setup_kfail "*-*-*" symtab/25507 }
> - gdb_test "next" "return 0.*" "next step 4"
> +
> + set ok 1
> + gdb_test_multiple "next" "next step 4" {
> + -re -wrap "(if \\(t != NULL|\} // get_alias_set)" {
> + send_gdb "next\n"
> + exp_continue
> + }
> + -re -wrap "return x;" {
> + set ok 0
> + send_gdb "next\n"
> + exp_continue
> + }
> + -re -wrap "return 0.*" {
> + if { $ok } {
> + pass $gdb_test_name
> + } else {
> + if { $have_kfail } {
> + setup_kfail "*-*-*" symtab/25507
> + }
> + fail $gdb_test_name
> + }
> + }
> + }
> gdb_test "bt" \
> "\\s*\\#0\\s+(main|get_alias_set)\[^\r\]*${srcfile}:.*" \
> "not in inline 5"
> diff --git a/gdb/testsuite/gdb.cp/step-and-next-inline.h b/gdb/testsuite/gdb.cp/step-and-next-inline.h
> index 8eb4b71d3cc..bf45d8a388c 100644
> --- a/gdb/testsuite/gdb.cp/step-and-next-inline.h
> +++ b/gdb/testsuite/gdb.cp/step-and-next-inline.h
> @@ -35,4 +35,4 @@ tree_check (tree *t, int i)
> abort();
> tree *x = t;
> return x;
> -}
> +} // tree_check
>