Bernd Edlinger reported the following problem and fix in find_epilogue_using_linetable ( https://sourceware.org/pipermail/gdb-patches/2024-April/207928.html ). This came up in a discussion for a patch for PR31268, but it's an independent issue. Consider the following test-case: ... $ cat hello.c #include <stdio.h> int main() { printf("hello "); #include "world.inc" /*** End of hello.c ***/ $ cat world.inc printf("world\n"); return 0; } /*** End of world.inc ***/ $ gcc -g -o hello hello.c ... The corresponding disassembly for main is: ... 0000000000400557 <main>: 400557: 55 push %rbp 400558: 48 89 e5 mov %rsp,%rbp 40055b: bf 24 06 40 00 mov $0x400624,%edi 400560: b8 00 00 00 00 mov $0x0,%eax 400565: e8 f6 fe ff ff call 400460 <printf@plt> 40056a: bf 2b 06 40 00 mov $0x40062b,%edi 40056f: e8 dc fe ff ff call 400450 <puts@plt> 400574: b8 00 00 00 00 mov $0x0,%eax 400579: 5d pop %rbp 40057a: c3 ret ... And the corresponding line table is: ... hello.c: File name Line number Starting address View Stmt hello.c 3 0x400557 x hello.c 4 0x40055b x ./world.inc:[++] world.inc 1 0x40056a x world.inc 2 0x400574 x world.inc 3 0x400579 x world.inc - 0x40057b ... Now, say we have an epilogue_begin marker at 0x400579 in world.inc. We won't find it using find_epilogue_using_linetable, because it does: ... const struct symtab_and_line sal = find_pc_line (start_pc, 0); ... which gets us the line table for hello.c. Proposed patch: ... - const struct symtab_and_line sal = find_pc_line (start_pc, 0); + const struct symtab_and_line sal = find_pc_line (end_pc - 1, 0); ... which gets us the linetable for world.inc instead.
https://sourceware.org/pipermail/gdb-patches/2024-April/207960.html
The master branch has been updated by Bernd Edlinger <edlinger@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=730f5068f5fb6613e4faa2efc2309cd107562cbd commit 730f5068f5fb6613e4faa2efc2309cd107562cbd Author: Bernd Edlinger <bernd.edlinger@hotmail.de> Date: Tue Apr 9 09:27:53 2024 +0000 Handle two-linetable function in find_epilogue_using_linetable Consider the following test-case: ... $ cat hello.c int main() { printf("hello "); #include "world.inc" $ cat world.inc printf("world\n"); return 0; } $ gcc -g hello.c ... The line table for the compilation unit, consisting just of function main, is translated into these two gdb line tables, one for hello.c and one for world.inc: ... compunit_symtab: hello.c symtab: hello.c INDEX LINE REL-ADDRESS UNREL-ADDRESS IS-STMT PROLOGUE-END EPILOGUE-BEGIN 0 3 0x400557 0x400557 Y 1 4 0x40055b 0x40055b Y 2 END 0x40056a 0x40056a Y compunit_symtab: hello.c symtab: world.inc INDEX LINE REL-ADDRESS UNREL-ADDRESS IS-STMT PROLOGUE-END EPILOGUE-BEGIN 0 1 0x40056a 0x40056a Y 1 2 0x400574 0x400574 Y 2 3 0x400579 0x400579 Y 3 END 0x40057b 0x40057b Y ... The epilogue of main starts at 0x400579: ... 400579: 5d pop %rbp 40057a: c3 ret ... Now, say we have an epilogue_begin marker in the line table at 0x400579. We won't find it using find_epilogue_using_linetable, because it does: ... const struct symtab_and_line sal = find_pc_line (start_pc, 0); ... which gets us the line table for hello.c. Fix this by using "find_pc_line (end_pc - 1, 0)" instead. Tested on x86_64-linux. Co-Authored-By: Tom de Vries <tdevries@suse.de> PR symtab/31622 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31622
fixed on master
Fixed.