/* Copyright 2020 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* This tests GDB's handling of the DWARF is-stmt field in the line table. This field is used when many addresses all represent the same source line. The address(es) at which it is suitable to place a breakpoint for a line are marked with is-stmt true, while address(es) that are not good places to place a breakpoint are marked as is-stmt false. In order to build a reproducible test and exercise GDB's is-stmt support, we will be generating our own DWARF. The test will contain a series of C source lines, ensuring that we get a series of assembler instructions. Each C source line will be given an assembler label, which we use to generate a fake line table. In this fake line table each assembler block is claimed to represent a single C source line, however, we will toggle the is-stmt flag. We can then debug this with GDB and test the handling of is-stmt. */ /* Used to insert labels with which we can build a fake line table. */ #define LL(N) asm ("line_label_" #N ": .globl line_label_" #N) volatile int var; volatile int bar; int main () { /* main prologue */ asm ("main_label: .globl main_label"); LL (1); var = 99; /* main, set var to 99 */ bar = 99; LL (2); var = 0; /* main, set var to 0 */ bar = 0; LL (3); var = 1; /* main, set var to 1 */ bar = 1; LL (4); var = 2; /* main, set var to 2 */ bar = 2; LL (5); return 0; /* main end */ } |