[Bug debug/105070] New: Missing debug info for switch statement
liyd2021 at gmail dot com
gcc-bugzilla@gcc.gnu.org
Sun Mar 27 16:27:50 GMT 2022
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105070
Bug ID: 105070
Summary: Missing debug info for switch statement
Product: gcc
Version: 11.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: liyd2021 at gmail dot com
Target Milestone: ---
Affected versions: gcc 11.1.0, since gcc 9
(terminal) $ gcc-9 -v
Using built-in specs.
COLLECT_GCC=gcc-9
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
9.4.0-1ubuntu1~20.04' --with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-9
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-gnu-unique-object --disable-vtable-verify --enable-plugin
--enable-default-pie --with-system-zlib --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-9-yTrUTS/gcc-9-9.4.0/debian/tmp-nvptx/usr,hsa
--without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04)
Debugging the following program will directly hit "return 1" instead of the
"switch (x)" in this specific case.
Did not observe this problem on other switch-cases.
(terminal) $ cat a.c && gcc -g -OO a.c
extern void abort(void);
int foo(int x) {
switch (x) {
case 1:
case 3:
case 5:
return 1;
default:
return 0;
}
}
int main() {
int i, r;
for (i = 0; i < 6; i++) {
r = foo(i);
if(i == 1 || i == 3 || i == 5){
if(r == 0){
abort();
}
}
}
return 0;
}
--------------------
(terminal) $ gdb a.out
(gdb) b foo
Breakpoint 1 at 0x4011b3: file a.c, line 8.
(gdb) r
Breakpoint 1, foo (x=1) at a.c:8
8 return 1;
(gdb) c
Continuing.
Breakpoint 1, foo (x=3) at a.c:8
8 return 1;
(gdb) c
Continuing.
Breakpoint 1, foo (x=5) at a.c:8
8 return 1;
This bug seemed to be missing debug_line.
(terminal) $ readelf --debug-dump=decodedline a.out
Contents of the .debug_line section:
CU: a.c:
File Line Starting address View Stmt
a.c 3 0x401185 x
a.c 8 0x4011b3 x <-- line 4 is missing
a.c 10 0x4011ba x
a.c 12 0x4011bf x
a.c 14 0x4011c1 x
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