[PATCH v3 4/6] Dwarf: Fortran, support DW_TAG_entry_point.

Tim Wiederhake
2017-08-11T11:07:36Z

From: Bernhard Heckel <bernhard.heckel@intel.com>

Fortran provides additional entry-points to an subprogram. Those entry-points
may have only a subset of parameters of the original subprogram as well.

Add support for parsing DW_TAG_entry_point's for Fortran.

xxxx-yy-zz Bernhard Heckel <bernhard.heckel@intel.com>
Tim Wiederhake <tim.wiederhake@intel.com>

gdb/ChangeLog:
PR fortran/8043
PR fortran/9279
* gdb/dwarf2read.c (add_partial_symbol): Handle DW_TAG_entry_point.
(add_partial_entry_point): New function.
(add_partial_subprogram): Search for entry_points.
(process_die): Handle DW_TAG_entry_point.
(dwarf2_get_pc_bounds): Update low pc from DWARF.
(load_partial_dies): Save DW_TAG_entry_point's.
(load_partial_dies): Save DW_TAG_entry_point to hash table.
(load_partial_dies): Look into child's of DW_TAG_sub_program
for fortran.
(new_symbol_full): Process DW_TAG_entry_point.
(read_type_die_1): Handle DW_TAG_entry_point.

gdb/testsuite/ChangeLog:
* gdb.fortran/entry_point.f90: New file.
* gdb.fortran/entry_point.exp: New file.

---
gdb/dwarf2read.c | 97 +++++++++++++++++++++++++++++--
gdb/testsuite/gdb.fortran/entry_point.exp | 70 ++++++++++++++++++++++
gdb/testsuite/gdb.fortran/entry_point.f90 | 48 +++++++++++++++
3 files changed, 211 insertions(+), 4 deletions(-)
create mode 100644 gdb/testsuite/gdb.fortran/entry_point.exp
create mode 100644 gdb/testsuite/gdb.fortran/entry_point.f90

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index b7df134..0349db0 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -1556,6 +1556,10 @@ static void add_partial_module (struct partial_die_info *pdi, CORE_ADDR *lowpc,
static void add_partial_enumeration (struct partial_die_info *enum_pdi,
struct dwarf2_cu *cu);

+static void add_partial_entry_point (struct partial_die_info *pdi,
+ CORE_ADDR *lowpc, CORE_ADDR *highpc,
+ int need_pc, struct dwarf2_cu *cu);
+
static void add_partial_subprogram (struct partial_die_info *pdi,
CORE_ADDR *lowpc, CORE_ADDR *highpc,
int need_pc, struct dwarf2_cu *cu);
@@ -7132,6 +7136,27 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)

switch (pdi->tag)
{
+ case DW_TAG_entry_point:
+ {
+ /* Don't know any other language than fortran which is
+ using DW_TAG_entry_point. */
+ if (cu->language == language_fortran)
+ {
+ addr = gdbarch_adjust_dwarf2_addr (gdbarch, pdi->lowpc + baseaddr);
+ /* DW_TAG_entry_point provides an additional entry_point to an
+ existing sub_program. Therefore, we inherit the "external"
+ attribute from the sub_program to which the entry_point
+ belongs to. */
+ auto psymbols = pdi->die_parent->is_external
+ ? &objfile->global_psymbols : &objfile->static_psymbols;
+
+ add_psymbol_to_list (actual_name, strlen (actual_name),
+ built_actual_name != NULL, VAR_DOMAIN,
+ LOC_BLOCK, psymbols, addr, cu->language,
+ objfile);
+ }
+ break;
+ }
case DW_TAG_subprogram:
addr = gdbarch_adjust_dwarf2_addr (gdbarch, pdi->lowpc + baseaddr);
if (pdi->is_external || cu->language == language_ada)
@@ -7333,6 +7358,18 @@ add_partial_module (struct partial_die_info *pdi, CORE_ADDR *lowpc,
scan_partial_symbols (pdi->die_child, lowpc, highpc, set_addrmap, cu);
}

+static void
+add_partial_entry_point (struct partial_die_info *pdi,
+ CORE_ADDR *p_lowpc, CORE_ADDR *p_highpc,
+ int set_addrmap, struct dwarf2_cu *cu)
+{
+ if (pdi->name == NULL)
+ complaint (&symfile_complaints,
+ _("DW_TAG_entry_point have to have a name"));
+ else
+ add_partial_symbol (pdi, cu);
+}
+
/* Read a partial die corresponding to a subprogram and create a partial
symbol for that subprogram. When the CU language allows it, this
routine also defines a partial symbol for each nested subprogram
@@ -7403,6 +7440,16 @@ add_partial_subprogram (struct partial_die_info *pdi,
pdi = pdi->die_sibling;
}
}
+ else if (cu->language == language_fortran)
+ {
+ pdi = pdi->die_child;
+ while (pdi != NULL)
+ {
+ if (pdi->tag == DW_TAG_entry_point)
+ add_partial_entry_point (pdi, lowpc, highpc, set_addrmap, cu);
+ pdi = pdi->die_sibling;
+ }
+ }
}

/* Read a partial die corresponding to an enumeration type. */
@@ -8509,6 +8556,7 @@ process_die (struct die_info *die, struct dwarf2_cu *cu)
case DW_TAG_type_unit:
read_type_unit_scope (die, cu);
break;
+ case DW_TAG_entry_point:
case DW_TAG_subprogram:
case DW_TAG_inlined_subroutine:
read_func_scope (die, cu);
@@ -12500,6 +12548,27 @@ dwarf2_get_pc_bounds (struct die_info *die, CORE_ADDR *lowpc,
CORE_ADDR high = 0;
enum pc_bounds_kind ret;

+ if (die->tag == DW_TAG_entry_point)
+ {
+ /* Entry_point is embedded in an subprogram. Therefore, we can use the
+ highpc from its enveloping subprogram and get the lowpc from DWARF. */
+ ret = dwarf2_get_pc_bounds (die->parent, lowpc, highpc, cu, pst);
+ if (ret == PC_BOUNDS_NOT_PRESENT || ret == PC_BOUNDS_INVALID)
+ return ret;
+
+ attr = dwarf2_attr (die, DW_AT_low_pc, cu);
+ if (!attr)
+ {
+ complaint (&symfile_complaints,
+ _("DW_TAG_entry_point is missing DW_AT_low_pc"));
+ return PC_BOUNDS_INVALID;
+ }
+ low = attr_value_as_address (attr);
+ *lowpc = low;
+
+ return PC_BOUNDS_HIGH_LOW;
+ }
+
attr_high = dwarf2_attr (die, DW_AT_high_pc, cu);
if (attr_high)
{
@@ -16030,6 +16099,7 @@ load_partial_dies (const struct die_reader_specs *reader,
&& abbrev->tag != DW_TAG_constant
&& abbrev->tag != DW_TAG_enumerator
&& abbrev->tag != DW_TAG_subprogram
+ && abbrev->tag != DW_TAG_entry_point
&& abbrev->tag != DW_TAG_lexical_block
&& abbrev->tag != DW_TAG_variable
&& abbrev->tag != DW_TAG_namespace
@@ -16156,6 +16226,7 @@ load_partial_dies (const struct die_reader_specs *reader,
if (load_all
|| abbrev->tag == DW_TAG_constant
|| abbrev->tag == DW_TAG_subprogram
+ || abbrev->tag == DW_TAG_entry_point
|| abbrev->tag == DW_TAG_variable
|| abbrev->tag == DW_TAG_namespace
|| part_die->is_declaration)
@@ -16181,7 +16252,9 @@ load_partial_dies (const struct die_reader_specs *reader,
For Ada, we need to scan the children of subprograms and lexical
blocks as well because Ada allows the definition of nested
entities that could be interesting for the debugger, such as
- nested subprograms for instance. */
+ nested subprograms for instance.
+
+ For Fortran, we need to scan the children of subprogram. */
if (last_die->has_children
&& (load_all
|| last_die->tag == DW_TAG_namespace
@@ -16198,7 +16271,9 @@ load_partial_dies (const struct die_reader_specs *reader,
|| last_die->tag == DW_TAG_union_type))
|| (cu->language == language_ada
&& (last_die->tag == DW_TAG_subprogram
- || last_die->tag == DW_TAG_lexical_block))))
+ || last_die->tag == DW_TAG_lexical_block))
+ || (cu->language == language_fortran
+ && last_die->tag == DW_TAG_subprogram)))
{
nesting_level++;
parent_die = last_die;
@@ -19061,12 +19136,25 @@ new_symbol_full (struct die_info *die, struct type *type, struct dwarf2_cu *cu,
SYMBOL_ACLASS_INDEX (sym) = LOC_LABEL;
add_symbol_to_list (sym, cu->list_in_scope);
break;
+ case DW_TAG_entry_point:
case DW_TAG_subprogram:
+ /* Don't know any other language than fortran which is
+ using DW_TAG_entry_point. */
+ if ((die->tag == DW_TAG_entry_point)
+ && (cu->language != language_fortran))
+ break;
+
/* SYMBOL_BLOCK_VALUE (sym) will be filled in later by
finish_block. */
SYMBOL_ACLASS_INDEX (sym) = LOC_BLOCK;
- attr2 = dwarf2_attr (die, DW_AT_external, cu);
- if ((attr2 && (DW_UNSND (attr2) != 0))
+
+ /* DW_TAG_entry_point provides an additional entry_point to an
+ existing sub_program. Therefore, we inherit the "external"
+ attribute from the sub_program to which the entry_point
+ belongs to. */
+ attr2 = dwarf2_attr (die->tag == DW_TAG_entry_point ? die->parent
+ : die, DW_AT_external, cu);
+ if ((attr2 != NULL && (DW_UNSND (attr2) != 0))
|| cu->language == language_ada)
{
/* Subprograms marked external are stored as a global symbol.
@@ -19746,6 +19834,7 @@ read_type_die_1 (struct die_info *die, struct dwarf2_cu *cu)
case DW_TAG_enumeration_type:
this_type = read_enumeration_type (die, cu);
break;
+ case DW_TAG_entry_point:
case DW_TAG_subprogram:
case DW_TAG_subroutine_type:
case DW_TAG_inlined_subroutine:
diff --git a/gdb/testsuite/gdb.fortran/entry_point.exp b/gdb/testsuite/gdb.fortran/entry_point.exp
new file mode 100644
index 0000000..1ed18a2
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/entry_point.exp
@@ -0,0 +1,70 @@
+# Copyright 2017 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/>.
+
+if { [skip_fortran_tests] } { return -1 }
+
+standard_testfile .f90
+load_lib "fortran.exp"
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug f90}]} {
+ return -1
+}
+
+if ![runto MAIN__] then {
+ untested "couldn't run to breakpoint MAIN__"
+ return -1
+}
+
+# Test if we can set a breakpoint via entry-point name
+set ept_name "foo"
+gdb_breakpoint $ept_name
+gdb_test "continue" \
+ [multi_line "Breakpoint $decimal, $ept_name \\(j=1, k=2, l=3, i1=4\\) at .*" \
+ ".*"] \
+ "continue to breakpoint: $ept_name"
+
+gdb_test "print j" "= 1" "print j, entered via $ept_name"
+gdb_test "print k" "= 2" "print k, entered via $ept_name"
+gdb_test "print l" "= 3" "print l, entered via $ept_name"
+gdb_test "print i1" "= 4" "print i1, entered via $ept_name"
+gdb_test "info args" \
+ [multi_line "j = 1" \
+ "k = 2" \
+ "l = 3" \
+ "i1 = 4"] \
+ "info args, entered via $ept_name"
+
+# Test if we can set a breakpoint via function name
+set ept_name "bar"
+gdb_breakpoint $ept_name
+gdb_test "continue" \
+ [multi_line "Breakpoint $decimal, $ept_name \\(i=4, j=5, k=6, i1=7\\) at .*" \
+ ".*"] \
+ "continue to breakpoint: $ept_name"
+
+gdb_test "print i" "= 4" "print i, entered via $ept_name"
+gdb_test "print j" "= 5" "print j, entered via $ept_name"
+gdb_test "print k" "= 6" "print k, entered via $ept_name"
+gdb_test "print i1" "= 7" "print i1, entered via $ept_name"
+
+set ept_name "baz"
+gdb_breakpoint $ept_name
+gdb_test "continue" \
+ [multi_line "Breakpoint $decimal, $ept_name \\(j=1\\) at .*" \
+ ".*"] \
+ "continue to breakpoint: $ept_name"
+
+gdb_test "print j" "= 1" "print j, entered via $ept_name"
+gdb_test "info args" "j = 1" "info args, entered via $ept_name"
diff --git a/gdb/testsuite/gdb.fortran/entry_point.f90 b/gdb/testsuite/gdb.fortran/entry_point.f90
new file mode 100644
index 0000000..1d43930
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/entry_point.f90
@@ -0,0 +1,48 @@
+! Copyright 2017 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/>.
+
+program TestEntryPoint
+
+ call foo(1,2,3,4)
+ call bar(4,5,6,7)
+ call baz(1)
+
+end program TestEntryPoint
+
+ subroutine bar(I,J,K,I1)
+ INTEGER I,J,K,L,I1
+ INTEGER A
+ REAL C
+
+ A = 0
+ C = 0.0
+
+ A = I + K + I1
+ goto 1000
+
+ entry foo(J,K,L,I1)
+ A = J + K + L + I1
+
+200 C = J
+ goto 1000
+
+ entry baz(J)
+ goto 200
+
+1000 A = C + 1
+ C = J * 1.5
+
+ return
+ end subroutine
--
2.7.4