[2/3] GDB: Bring back the handling of DW_CC_program
Commit Message
Fix a functional regression and restore the handling of DW_CC_program
code of DW_AT_calling_convention attribute for determining the name of
the starting function of the program where the DW_AT_main_subprogram
attribute has not been provided, such as with Fortran code compiled with
GCC versions 4.5.4 and below, or where DWARF version 3 or below has been
requested. Without it "main" is considered the starting function. Cf.
GCC PR fortran/43414.
Original code was removed with commit 6209cde4ddb8 ("Delete DWARF
psymtab code"), and then an update to complement commit 81873cc81eff
("[gdb/symtab] Support DW_AT_main_subprogram with -readnow.") has also
been included here.
---
NB this was discovered with and is covered by the test case included with
3/3; it has been verified to trigger with GCC 4.4.7 and will likely also
with other configurations.
---
gdb/dwarf2/read.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
gdb-main-name-dw-cc-program.diff
===================================================================
@@ -9994,6 +9994,18 @@ inherit_abstract_dies (struct die_info *
compute_delayed_physnames (origin_cu);
}
+/* Return TRUE if the given DIE is the program's "main". */
+
+static bool
+dwarf2_func_is_main_p (struct die_info *die, struct dwarf2_cu *cu)
+{
+ if (dwarf2_flag_true_p (die, DW_AT_main_subprogram, cu))
+ return true;
+ struct attribute *attr = dwarf2_attr (die, DW_AT_calling_convention, cu);
+ return (attr != nullptr
+ && attr->constant_value (DW_CC_normal) == DW_CC_program);
+}
+
static void
read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
{
@@ -10084,7 +10096,7 @@ read_func_scope (struct die_info *die, s
newobj = cu->get_builder ()->push_context (0, lowpc);
newobj->name = new_symbol (die, read_type_die (die, cu), cu, templ_func);
- if (dwarf2_flag_true_p (die, DW_AT_main_subprogram, cu))
+ if (dwarf2_func_is_main_p (die, cu))
set_objfile_main_name (objfile, newobj->name->linkage_name (),
cu->lang ());
@@ -16141,6 +16153,11 @@ cooked_indexer::scan_attributes (dwarf2_
*flags |= IS_MAIN;
break;
+ case DW_AT_calling_convention:
+ if (attr.constant_value (DW_CC_normal) == DW_CC_program)
+ *flags |= IS_MAIN;
+ break;
+
case DW_AT_declaration:
is_declaration = attr.as_boolean ();
break;