| Summary: | inconsistent behaviors at -O2 | ||
|---|---|---|---|
| Product: | gdb | Reporter: | Anonymous <iamanonymous.cs> |
| Component: | gdb | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED DUPLICATE | ||
| Severity: | normal | CC: | rguenth |
| Priority: | P2 | ||
| Version: | HEAD | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | ||
gdb does not support location views. this is all known behaviour. (gdb) maint info line-table objfile: /home/yibiao/DeVIL/a.out ((struct objfile *) 0x557a30fda120) compunit_symtab: ((struct compunit_symtab *) 0x557a30fd1400) symtab: /home/yibiao/DeVIL/small.c ((struct symtab *) 0x557a30fd1480) linetable: ((struct linetable *) 0x557a3101af00): INDEX LINE ADDRESS IS-STMT 0 5 0x0000555555555080 Y 1 7 0x0000555555555088 2 6 0x000055555555508d 3 7 0x00005555555550a1 4 8 0x00005555555550a6 5 6 0x00005555555550ae 6 7 0x00005555555550b3 Y 7 8 0x00005555555550b3 Y 8 7 0x00005555555550b3 9 6 0x00005555555550b8 10 6 0x00005555555550bb 11 7 0x00005555555550c5 12 8 0x00005555555550cb 13 7 0x00005555555550d1 14 8 0x00005555555550d3 15 7 0x00005555555550d6 16 8 0x00005555555550da 17 9 0x00005555555550e2 Y 18 10 0x00005555555550e2 19 END 0x00005555555550fc Y *** This bug has been marked as a duplicate of bug 25507 *** |
Consider test case: ... $ cat small.c #include <string.h> volatile int one = 1; int main() { char a1[] = {(char)one, 2, 3, 4}; char a2[] = {1, (char)(2*one), 3, 4}; int res = memcmp (a1, a2, 5 + one); return res; } ... When stepping using step Line 7 is not hit by gdb. ... $ gcc -O2 -g small.c; gdb -q a.out Reading symbols from a.out... (gdb) b main Breakpoint 1 at 0x401040: file small.c, line 6. (gdb) r Starting program: /home/yibiao/Debugger/a.out Breakpoint 1, main () at small.c:6 6 char a1[] = {(char)one, 2, 3, 4}; (gdb) step 8 int res = memcmp (a1, a2, 5 + one); (gdb) ... When stepping using stepi, Line 7 is hit after Line 6 by gdb. ... $ gcc -O2 -g small.c; gdb -q a.out Reading symbols from a.out... (gdb) b main Breakpoint 1 at 0x401040: file small.c, line 6. (gdb) si The program is not being run. (gdb) r Starting program: /home/yibiao/Debugger/a.out Breakpoint 1, main () at small.c:6 6 char a1[] = {(char)one, 2, 3, 4}; (gdb) si 0x0000000000401044 6 char a1[] = {(char)one, 2, 3, 4}; (gdb) si 0x000000000040104a 7 char a2[] = {1, (char)(2*one), 3, 4}; (gdb) $ gcc --version gcc (GCC) 10.0.1 20200419 (experimental) Copyright (C) 2020 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ gdb --version GNU gdb (GDB) 10.0.50.20200517-git Copyright (C) 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.