From 525174e886044ce3538b13545939421032f77a1b Mon Sep 17 00:00:00 2001 From: Felix Willgerodt Date: Tue, 20 Apr 2021 08:43:08 +0200 Subject: [PATCH] gdb: Allow address space qualifier parsing in C++. The goal of this patch is to allow target dependent address space qualifiers in the C++ expression parser. This can be useful for memory examination on targets that actually use different address spaces in hardware without having to deep-dive into implementation details of the whole solution. GDB uses the @ symbol to parse address space qualifiers. The only current user that I am aware of is the __flash support for avr, which was added in "Add support for the __flash qualifier on AVR" (487d975399dfcb2bb2f0998a7d12bd62acdd9fa1) and only works for C. One use-case of the AVR patch is: ~~~ const __flash char data_in_flash = 0xab; int main (void) { const __flash char *pointer_to_flash = &data_in_flash; } ~~~ ~~~ (gdb) print pointer_to_flash $1 = 0x1e8 "\253" (gdb) print/x *pointer_to_flash $2 = 0xab (gdb) x/x pointer_to_flash 0x1e8 : 0xXXXXXXab (gdb) (gdb) p/x *(char* @flash) pointer_to_flash $3 = 0xab ~~~ I want to enable a similar usage of e.g. @local in C++. Before this patch (using "set debug parser on"): ~~~ (gdb) p *(int* @local) 0x1234 (...) Reading a token: Next token is token '@' () Shifting token '@' () Entering state 46 Reading a token: Next token is token UNKNOWN_CPP_NAME (ssym) A syntax error in expression, near `local) &x'. ~~~ After: ~~~ (gdb) p *(int* @local) 0x1234 (...) Reading a token: Next token is token '@' () Shifting token '@' () Entering state 46 Reading a token: Next token is token UNKNOWN_CPP_NAME (ssym) Shifting token UNKNOWN_CPP_NAME (ssym) Entering state 121 Reducing stack by rule 278 (line 1773): $1 = token UNKNOWN_CPP_NAME (ssym) -> $$ = nterm name () Stack now 0 49 52 76 222 337 46 Entering state 167 Reducing stack by rule 131 (line 1225): $1 = token '@' () $2 = nterm name () Unknown address space specifier: "local" ~~~ The "Unknown address space qualifier" is the right behaviour, as I ran this on a target that doesn't have multiple address spaces and therefore obviously no support for such qualifiers. gdb/ChangeLog: 2021-04-20 Felix Willgerodt * c-exp.y (single_qualifier): Handle UNKNOWN_CPP_NAME. gdb/testsuite/ChangeLog: 2021-04-20 Felix Willgerodt * gdb.base/address_space_qualifier.exp: New file. --- gdb/ChangeLog | 4 +++ gdb/c-exp.y | 5 +++ gdb/testsuite/ChangeLog | 4 +++ .../gdb.base/address_space_qualifier.exp | 35 +++++++++++++++++++ 4 files changed, 48 insertions(+) create mode 100644 gdb/testsuite/gdb.base/address_space_qualifier.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index a7f079e70e3..8692c0f8c43 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,7 @@ +2021-04-20 Felix Willgerodt + + * c-exp.y (single_qualifier): Handle UNKNOWN_CPP_NAME. + 2021-04-19 Andrew Burgess * producer.c: Replace 'regex' include with 'gdb_regex.h'. diff --git a/gdb/c-exp.y b/gdb/c-exp.y index 865b1554de1..3e416f4e2c7 100644 --- a/gdb/c-exp.y +++ b/gdb/c-exp.y @@ -1267,6 +1267,11 @@ single_qualifier: cpstate->type_stack.insert (pstate, copy_name ($2.stoken).c_str ()); } + | '@' UNKNOWN_CPP_NAME + { + cpstate->type_stack.insert (pstate, + copy_name ($2.stoken).c_str ()); + } ; qualifier_seq_noopt: diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 2bc845c0275..68e46652581 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2021-04-20 Felix Willgerodt + + * gdb.base/address_space_qualifier.exp: New file. + 2021-04-19 Tom Tromey PR gdb/27742: diff --git a/gdb/testsuite/gdb.base/address_space_qualifier.exp b/gdb/testsuite/gdb.base/address_space_qualifier.exp new file mode 100644 index 00000000000..b8209dc565b --- /dev/null +++ b/gdb/testsuite/gdb.base/address_space_qualifier.exp @@ -0,0 +1,35 @@ +# Copyright 2021 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 . */ + +# Regression test for expression evaluation of address space qualifiers +# in C and C++. + +gdb_exit +gdb_start +gdb_reinitialize_dir $srcdir/$subdir + +gdb_test_no_output "set language c" + +with_test_prefix "C" { + gdb_test "p *(@somerandomqualifiername int *) 0x12345678" \ + "Unknown address space specifier: \"somerandomqualifiername\"" +} + +gdb_test_no_output "set language c++" + +with_test_prefix "C++" { + gdb_test "p *(@somerandomqualifiername int *) 0x12345678" \ + "Unknown address space specifier: \"somerandomqualifiername\"" +} -- 2.30.2