https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113182
Bug ID: 113182
Summary: [14 Regression] FAIL: g++.dg/cpp0x/udlit-namespace.C
-std=c++14 execution test
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
Assignee: unassigned at gcc dot gnu.org
Reporter: danglin at gcc dot gnu.org
CC: jemarch at gcc dot gnu.org
Target Milestone: ---
Host: hppa64-hp-hpux11.11
Target: hppa64-hp-hpux11.11
Build: hppa64-hp-hpux11.11
Executing on host: /home/dave/gnu/gcc/objdir64/gcc/testsuite/g++/../../xg++
-B/h
ome/dave/gnu/gcc/objdir64/gcc/testsuite/g++/../../ exceptions_enabled19821.cc
-fdiagnostics-plain-output -nostdinc++
-I/home/dave/gnu/gcc/objdir64/hppa64-h
p-hpux11.11/libstdc++-v3/include/hppa64-hp-hpux11.11
-I/home/dave/gnu/gcc/objdir
64/hppa64-hp-hpux11.11/libstdc++-v3/include
-I/home/dave/gnu/gcc/gcc/libstdc++-v
3/libsupc++ -I/home/dave/gnu/gcc/gcc/libstdc++-v3/include/backward
-I/home/dave/
gnu/gcc/gcc/libstdc++-v3/testsuite/util -fmessage-length=0
-Wno-complain-wrong-l
ang -S -o exceptions_enabled19821.s (timeout = 300)
spawn -ignore SIGHUP /home/dave/gnu/gcc/objdir64/gcc/testsuite/g++/../../xg++
-B
/home/dave/gnu/gcc/objdir64/gcc/testsuite/g++/../../ exceptions_enabled19821.cc
-fdiagnostics-plain-output -nostdinc++
-I/home/dave/gnu/gcc/objdir64/hppa64-hp-h
pux11.11/libstdc++-v3/include/hppa64-hp-hpux11.11
-I/home/dave/gnu/gcc/objdir64/
hppa64-hp-hpux11.11/libstdc++-v3/include
-I/home/dave/gnu/gcc/gcc/libstdc++-v3/l
ibsupc++ -I/home/dave/gnu/gcc/gcc/libstdc++-v3/include/backward
-I/home/dave/gnu
/gcc/gcc/libstdc++-v3/testsuite/util -fmessage-length=0
-Wno-complain-wrong-lang
-S -o exceptions_enabled19821.s
PASS: g++.dg/cpp0x/udlit-namespace.C -std=c++14 (test for excess errors)
Setting LD_LIBRARY_PATH to
.:/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/.libs:/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/.libs:/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/experimental/.libs:/home/dave/gnu/gcc/objdir64/gcc/testsuite/g++/../..:.:/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/.libs:/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/.libs:/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/experimental/.libs:/home/dave/gnu/gcc/objdir64/gcc/testsuite/g++/../..
Execution timeout is: 300
spawn [open ...]
FAIL: g++.dg/cpp0x/udlit-namespace.C -std=c++14 execution test
Similar fails:
FAIL: g++.dg/cpp0x/udlit-namespace.C -std=c++17 execution test
FAIL: g++.dg/cpp0x/udlit-namespace.C -std=c++20 execution test
(gdb) r
Starting program:
/home/dave/gnu/gcc/objdir64/gcc/testsuite/g++/udlit-namespace.exe
Program received signal SIGSEGV, Segmentation fault.
0x800003ffbfcd3000 in ?? ()
from
/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/.libs/libstdc++.sl.6
(gdb) bt
#0 0x800003ffbfcd3000 in ?? ()
from
/home/dave/gnu/gcc/objdir64/hppa64-hp-hpux11.11/./libstdc++-v3/src/.libs/libstdc++.sl.6
#1 0x800003ffbfe5f3f4 in fmodl (x=<optimized out>, y=<optimized out>)
at ../../../../../gcc/libstdc++-v3/src/c++98/math_stubs_long_double.cc:117
Backtrace stopped: Cannot access memory at address 0x3333333333333323
This problem was introduced by the following commit:
bash-5.1$ git bisect bad
f31a019d1161ec78846473da743aedf49cca8c27 is the first bad commit
commit f31a019d1161ec78846473da743aedf49cca8c27
Author: Jose E. Marchesi <jose.march...@oracle.com>
Date: Fri Nov 24 06:30:28 2023 +0100
Emit funcall external declarations only if actually used.
There are many places in GCC where alternative local sequences are
tried in order to determine what is the cheapest or best alternative
to use in the current target. When any of these sequences involve a
libcall, the current implementation of emit_library_call_value_1
introduce a side-effect consisting on emitting an external declaration
for the funcall (such as __divdi3) which is thus emitted even if the
sequence that does the libcall is not retained.
This is problematic in targets such as BPF, because the kernel loader
chokes on the spurious symbol __divdi3 and makes the resulting BPF
object unloadable. Note that BPF objects are not linked before being
loaded.
This patch changes asssemble_external_libcall to defer emitting
declarations of external libcall symbols, by saving the call tree
nodes in a temporary list pending_libcall_symbols and letting
process_pending_assembly_externals to emit them only if they have been
referenced. Solution suggested and sketched by Richard Sandiford.
Regtested in x86_64-linux-gnu.
Tested with host x86_64-linux-gnu with target bpf-unknown-none.
gcc/ChangeLog
PR target/109253
* varasm.cc (pending_libcall_symbols): New variable.
(process_pending_assemble_externals): Process
pending_libcall_symbols.
(assemble_external_libcall): Defer emitting external libcall
symbols to process_pending_assemble_externals.
gcc/testsuite/ChangeLog
PR target/109253
* gcc.target/bpf/divmod-libcall-1.c: New test.
* gcc.target/bpf/divmod-libcall-2.c: Likewise.
* gcc.c-torture/compile/libcall-2.c: Likewise.
gcc/testsuite/gcc.c-torture/compile/libcall-2.c | 8 ++++++++
gcc/testsuite/gcc.target/bpf/divmod-libcall-1.c | 19 +++++++++++++++++++
gcc/testsuite/gcc.target/bpf/divmod-libcall-2.c | 16 ++++++++++++++++
gcc/varasm.cc | 22 +++++++++++++++++++++-
4 files changed, 64 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.c-torture/compile/libcall-2.c
create mode 100644 gcc/testsuite/gcc.target/bpf/divmod-libcall-1.c
create mode 100644 gcc/testsuite/gcc.target/bpf/divmod-libcall-2.c
The problem is we have lost the types for libcall symbols.
bash-5.1$ /usr/bin/nm
./hppa64-hp-hpux11.11/libstdc++-v3/src/c++98/math_stubs_long_double.o|less
[Index] Value Size Type Bind O Shndx Name
[0] | 0| 0|NOTYP|LOCAL|0| UNDEF|
...
[69] | 0| 0|NOTYP|GLOB |0| UNDEF|_U_Qfadd
[43] | 0| 0|NOTYP|GLOB |0|
UNDEF|_U_Qfcnvff_dbl_to_quad
[42] | 0| 0|NOTYP|GLOB |0|
UNDEF|_U_Qfcnvff_quad_to_dbl
[71] | 0| 0|NOTYP|GLOB |0| UNDEF|_U_Qfdiv
[70] | 0| 0|NOTYP|GLOB |0| UNDEF|_U_Qfeq
[72] | 0| 0|NOTYP|GLOB |0| UNDEF|_U_Qfmpy
[45] | 0| 0|FUNC |GLOB |0| UNDEF|acos
[44] | 0| 64|FUNC |GLOB |0|.text.acosl|acosl
_U_Qfcnvff_dbl_to_quad, etc, need to have type FUNC. The HP linker does
not correctly handle calls to symbols that have type NOTYP. As a result,
the call to _U_Qfcnvff_dbl_to_quad branches to a data address. This
generates a segmentation fault.
See pa_init_libfuncs() in pa.cc.
