This patch adds support for DW_AT_main_subprogram.
This is PR symtab/16264.
DW_AT_main_subprogram is used to mark a program's entry point. GCC
can emit this, and I hope to change the Rust compiler to emit it as
well.
GDB already supports an older, pre-DWARF 4 convention adopted by
FORTRAN compilers, namely to emit DW_AT_calling_convention for the
"main" function. However, I think this support in GDB had a small
bug, in that it seems to rely on the DW_AT_name being read before
DW_AT_calling_convention. This patch fixes this as well.
Built and regtested on x86-64 Fedora 24 and the buildbot. New test
case included.
2016-12-02 Tom Tromey <tom@tromey.com>
PR symtab/16264:
* dwarf2read.c (struct partial_die_info) <main_subprogram>: New
member.
(add_partial_symbol): Call set_objfile_main_name.
(read_partial_die): Handle DW_AT_main_subprogram.
<DW_AT_calling_convention>: don't call set_objfile_main_name, but
set main_subprogram flag.
2016-12-02 Tom Tromey <tom@tromey.com>
* gdb.dwarf2/main-subprogram.c: New file.
* gdb.dwarf2/main-subprogram.exp: New file.
+2016-12-02 Tom Tromey <tom@tromey.com>
+
+ PR symtab/16264:
+ * dwarf2read.c (struct partial_die_info) <main_subprogram>: New
+ member.
+ (add_partial_symbol): Call set_objfile_main_name.
+ (read_partial_die): Handle DW_AT_main_subprogram.
+ <DW_AT_calling_convention>: don't call set_objfile_main_name, but
+ set main_subprogram flag.
+
2016-12-02 Simon Marchi <simon.marchi@ericsson.com>
* tracefile-tfile.c (tfile_write_status): Adjust to renames.
unsigned int has_pc_info : 1;
unsigned int may_be_inlined : 1;
+ /* This DIE has been marked DW_AT_main_subprogram. */
+ unsigned int main_subprogram : 1;
+
/* Flag set if the SCOPE field of this structure has been
computed. */
unsigned int scope_set : 1;
&objfile->static_psymbols,
addr, cu->language, objfile);
}
+
+ if (pdi->main_subprogram && actual_name != NULL)
+ set_objfile_main_name (objfile, actual_name, cu->language);
break;
case DW_TAG_constant:
{
to describe functions' calling conventions.
However, because it's a necessary piece of information in
- Fortran, and because DW_CC_program is the only piece of debugging
- information whose definition refers to a 'main program' at all,
- several compilers have begun marking Fortran main programs with
- DW_CC_program --- even when those functions use the standard
- calling conventions.
-
- So until DWARF specifies a way to provide this information and
- compilers pick up the new representation, we'll support this
- practice. */
+ Fortran, and before DWARF 4 DW_CC_program was the only
+ piece of debugging information whose definition refers to
+ a 'main program' at all, several compilers marked Fortran
+ main programs with DW_CC_program --- even when those
+ functions use the standard calling conventions.
+
+ Although DWARF now specifies a way to provide this
+ information, we support this practice for backward
+ compatibility. */
if (DW_UNSND (&attr) == DW_CC_program
- && cu->language == language_fortran
- && part_die->name != NULL)
- set_objfile_main_name (objfile, part_die->name, language_fortran);
+ && cu->language == language_fortran)
+ part_die->main_subprogram = 1;
break;
case DW_AT_inline:
if (DW_UNSND (&attr) == DW_INL_inlined
}
break;
+ case DW_AT_main_subprogram:
+ part_die->main_subprogram = DW_UNSND (&attr);
+ break;
+
default:
break;
}
+2016-12-02 Tom Tromey <tom@tromey.com>
+
+ * gdb.dwarf2/main-subprogram.c: New file.
+ * gdb.dwarf2/main-subprogram.exp: New file.
+
2016-12-01 Luis Machado <lgustavo@codesourcery.com>
* gdb.base/maint.exp: Remove timeout handling for gdb_test_multiple.
--- /dev/null
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2016 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/>. */
+
+int
+mymain ()
+{
+ asm ("mymain_label: .globl mymain_label");
+ return 0;
+}
+
+int
+main()
+{
+ return mymain ();
+}
--- /dev/null
+# Copyright 2016 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/>.
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-4 and use gas.
+if {![dwarf2_support]} {
+ return 0
+}
+
+standard_testfile main-subprogram.c enum-type-dw.S
+
+# Make some DWARF for the test.
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+ global srcdir subdir srcfile
+
+ set range [function_range mymain ${srcdir}/${subdir}/${srcfile}]
+ set mymain_start [lindex $range 0]
+ set mymain_length [lindex $range 1]
+
+ cu {} {
+ DW_TAG_compile_unit {
+ {DW_AT_language @DW_LANG_C}
+ {DW_AT_name main-subprogram.c}
+ {DW_AT_comp_dir /tmp}
+ } {
+ declare_labels type
+
+ type: DW_TAG_base_type {
+ {DW_AT_byte_size 4 DW_FORM_sdata}
+ {DW_AT_encoding @DW_ATE_signed}
+ {DW_AT_name int}
+ }
+
+ DW_TAG_subprogram {
+ {name mymain}
+ {low_pc $mymain_start addr}
+ {high_pc "$mymain_start + $mymain_length" addr}
+ {type :$type}
+ {DW_AT_main_subprogram 1 flag}
+ } {
+ }
+ }
+ }
+}
+
+if {[prepare_for_testing ${testfile}.exp ${testfile} \
+ [list $srcfile $asm_file] {nodebug}]} {
+ return -1
+}
+
+# Test that the "start" command stops in the "mymain" function.
+# This should happen because we used DW_AT_main_subprogram to tell gdb
+# that this was the real "main".
+
+if {[gdb_start_cmd] < 0} {
+ untested "could not start ${testfile}"
+ return -1
+}
+
+gdb_test "" "Temporary breakpoint .* mymain.*" "stopped at mymain"
projects / binutils-gdb.git / commitdiff