Dwarf: Fortran, support DW_TAG_entry_point.

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.

2016-06-01  Bernhard Heckel  <bernhard.heckel@intel.com>

gdb/Changelog:
	* gdb/dwarf2read.c (add_partial_symbol): Handle DW_TAG_entry_point.
	(add_partial_entry_point): New.
	(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.
	* gdb.fortran/entry_point.exp: New.

Change-Id: I886699802fc940cd9b995806c32a85a05cf57dc4

3 files changed, 204 insertions, 1 deletions

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index ed10e03812f..945ca614ac1 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -1425,6 +1425,10 @@ 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);
@@ -6911,6 +6915,25 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
 
   switch (pdi->tag)
     {
+    case DW_TAG_entry_point:
+      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.  */
+      if (pdi->die_parent->is_external)
+	add_psymbol_to_list (actual_name, strlen (actual_name),
+			     built_actual_name != NULL,
+			     VAR_DOMAIN, LOC_BLOCK,
+			     &objfile->global_psymbols,
+			     addr, cu->language, objfile);
+      else
+	add_psymbol_to_list (actual_name, strlen (actual_name),
+			     built_actual_name != NULL,
+			     VAR_DOMAIN, LOC_BLOCK,
+			     &objfile->static_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)
@@ -7108,6 +7131,17 @@ 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
@@ -7178,6 +7212,16 @@ 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.  */
@@ -8282,6 +8326,7 @@ 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);
@@ -12063,6 +12108,27 @@ 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 it's enveloping subprogram and get the
+         lowpc from DWARF.  */
+      if (PC_BOUNDS_INVALID == dwarf2_get_pc_bounds (die->parent, lowpc, highpc, cu, pst))
+	return PC_BOUNDS_INVALID;
+
+      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)
     {
@@ -15632,6 +15698,7 @@ 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
@@ -15758,6 +15825,7 @@ 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)
@@ -15799,7 +15867,9 @@ 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;
@@ -18440,6 +18510,20 @@ 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:
+	  /* SYMBOL_BLOCK_VALUE (sym) will be filled in later by
+	     finish_block.  */
+	  SYMBOL_ACLASS_INDEX (sym) = LOC_BLOCK;
+	  /* 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->parent, DW_AT_external, cu);
+	  if (attr2 && (DW_UNSND (attr2) != 0))
+	    list_to_add = &global_symbols;
+	  else
+	    list_to_add = cu->list_in_scope;
+	  break;
 	case DW_TAG_subprogram:
 	  /* SYMBOL_BLOCK_VALUE (sym) will be filled in later by
 	     finish_block.  */
@@ -19124,6 +19208,7 @@ 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 100755
index 00000000000..5c3accf3505
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/entry_point.exp
@@ -0,0 +1,70 @@
+# 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/>.

+

+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 {

+    perror "couldn't run to breakpoint MAIN__"

+    continue

+}

+

+# 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 "tim"

+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 100755
index 00000000000..1aa6fbd9ab3
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/entry_point.f90
@@ -0,0 +1,48 @@
+! 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/>.

+

+program TestEntryPoint

+

+  call foo(1,2,3,4)

+  call bar(4,5,6,7)

+  call tim(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 tim(J)

+    goto 200

+

+1000 A = C + 1

+     C = J * 1.5

+

+    return

+  end subroutine