/* Copyright 2018-2020 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/>. */ /* The idea here is to, via use of the dwarf assembler, create a function which occupies two non-contiguous address ranges. foo_cold and foo will be combined into a single function foo with a function bar in between these two ranges. This test case was motivated by a bug in which a function which occupied two non-contiguous address ranges was calling another function which resides in between these ranges. So we end up with a situation in which the low/start address of our constructed foo (in this case) will be less than any of the addresses in bar, but the high/end address of foo will be greater than any of bar's addresses. This situation was causing a problem in the caching code of find_pc_partial_function: When the low and high addresses of foo are placed in the cache, the simple check that was used to see if the cache was applicable would (incorrectly) succeed when presented with an address in bar. I.e. an address in bar presented as an input to find_pc_partial_function could produce the answer "this address belongs to foo". */ volatile int e = 0; void bar (void); void foo_cold (void); void baz (void); void foo (void) { /* foo prologue */ asm ("foo_label: .globl foo_label"); bar (); /* foo bar call */ asm ("foo_label2: .globl foo_label2"); if (e) foo_cold (); /* foo foo_cold call */ asm ("foo_label3: .globl foo_label3"); } /* foo end */ void bar (void) { asm ("bar_label: .globl bar_label"); } /* bar end */ void foo_cold (void) { /* foo_cold prologue */ asm ("foo_cold_label: .globl foo_cold_label"); baz (); /* foo_cold baz call */ asm ("foo_cold_label2: .globl foo_cold_label2"); } /* foo_cold end */ void baz (void) { asm ("baz_label: .globl baz_label"); } /* baz end */ int main (void) { /* main prologue */ asm ("main_label: .globl main_label"); foo (); /* main foo call */ asm ("main_label2: .globl main_label2"); return 0; /* main return */ } /* main end */ |