[binutils-gdb] gdb/dwarf: Use the function scope for DW_TAG_imported_declaration

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=90fe72f797828eabae2a876f7b4356ca7845123c

commit 90fe72f797828eabae2a876f7b4356ca7845123c
Author: Abdul Basit Ijaz <[email protected]>
Date:   Wed Apr 8 10:03:57 2026 +0200

    gdb/dwarf: Use the function scope for DW_TAG_imported_declaration
    
    All Fortran imported variable aliases (`use module, alias => var`)
    were being added to "global scope", regardless of whether they appeared
    in:
    - Program/module scope (should be global)
    - Function scope (should be local)
    
    This caused conflicts when different functions had the same alias name
    pointing to different variables.
    
    DW_TAG_imported_declaration and DW_TAG_namespace cases are now handled
    separately.  This patch modifies the case for DW_TAG_imported_
    declaration in the function new_symbol () to use cu->list_in_scope
    instead of global symbols for all languages.  This ensures that
    function-scoped aliases use the current scope rather than being forced
    into the global scope.
    
    Bug Scenario:
    
      subroutine sub1
        use mod1, var_i_alias=>var_i  ! alias points to mod1::var_i
        var_i_alias = 3
        var_i = 4
      end subroutine
    
      subroutine sub2
        use mod2, var_i_alias=>var_i  ! alias points to mod2::var_i
        var_i_alias = 23
        var_i = 25
      end subroutine
    
    Before: var_i_alias in sub2 incorrectly resolved to mod1::var_i
    (value 25)
    After: Each function's alias correctly resolves to its own imported
    variable (value 23)
    
    New test files verify the fix and include regression tests for global
    program-scope imports:
      - gdb/testsuite/gdb.fortran/module_declarations.exp
      - gdb/testsuite/gdb.fortran/module_declarations.f90
    
    Before the change:
    (gdb) print var_i_alias
    $4 = 25
    FAIL: gdb.fortran/module_declarations.exp: sub2_test: print var_i_alias
    
    After the change:
    (gdb) print var_i_alias
    $4 = 23
    PASS: gdb.fortran/module_declarations.exp: sub2_test: print var_i_alias
    
    Approved-By: Tom Tromey <[email protected]>

Diff:
---
 gdb/dwarf2/read.c                                 | 10 ++++
 gdb/testsuite/gdb.fortran/module_declarations.exp | 62 +++++++++++++++++++++++
 gdb/testsuite/gdb.fortran/module_declarations.f90 | 59 +++++++++++++++++++++
 3 files changed, 131 insertions(+)

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index a1081da2317..efe96f6510d 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -15846,6 +15846,16 @@ new_symbol (struct die_info *die, struct dwarf2_cu *cu, struct symbol *sym,
 	   : cu->list_in_scope);
       break;
     case DW_TAG_imported_declaration:
+      sym->set_domain (TYPE_DOMAIN);
+      sym->set_loc_class_index (LOC_TYPEDEF);
+      /* Use current scope context rather than forcing global scope.  This
+	 ensures variable aliases are scoped correctly (function-level,
+	 module-level, or program-level).  */
+      list_to_add
+	= ((cu->list_in_scope == &cu->get_builder ()->get_file_symbols ())
+	   ? &cu->get_builder ()->get_global_symbols ()
+	   : cu->list_in_scope);
+      break;
     case DW_TAG_namespace:
       sym->set_domain (TYPE_DOMAIN);
       sym->set_loc_class_index (LOC_TYPEDEF);
diff --git a/gdb/testsuite/gdb.fortran/module_declarations.exp b/gdb/testsuite/gdb.fortran/module_declarations.exp
new file mode 100644
index 00000000000..8953841c599
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/module_declarations.exp
@@ -0,0 +1,62 @@
+# Copyright 2026 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 "fortran.exp"
+
+require allow_fortran_tests
+
+standard_testfile .f90
+
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile {debug f90}] } {
+    return
+}
+
+if {![fortran_runto_main]} {
+    return
+}
+
+# Test global alias at program scope
+gdb_breakpoint [gdb_get_line_number "bp-main"]
+gdb_continue_to_breakpoint "bp-main" ".*bp-main.*"
+
+with_test_prefix "global_test" {
+    gdb_test "print global_alias" " = 200"
+    gdb_test "print global_var_i_from_mod1" " = 300"
+}
+
+gdb_breakpoint [gdb_get_line_number "bp-sub1"]
+gdb_continue_to_breakpoint "bp-sub1" ".*bp-sub1.*"
+
+with_test_prefix "sub1_test" {
+    gdb_test "print var_i_alias" " = 3"
+    gdb_test "print var_i" " = 4"
+}
+
+gdb_breakpoint [gdb_get_line_number "bp-sub2"]
+gdb_continue_to_breakpoint "bp-sub2" ".*bp-sub2.*"
+
+with_test_prefix "sub2_test" {
+    gdb_test "print var_i_alias" " = 23"
+    gdb_test "print var_i" " = 25"
+}
+
+# Test same-name variables shadowed within same function
+gdb_breakpoint [gdb_get_line_number "bp-sub3"]
+gdb_continue_to_breakpoint "bp-sub3" ".*bp-sub3.*"
+
+with_test_prefix "sub3_shadow_test" {
+    gdb_test "print var_i_from_mod1" " = 31"
+    gdb_test "print var_i_from_mod2" " = 32"
+}
diff --git a/gdb/testsuite/gdb.fortran/module_declarations.f90 b/gdb/testsuite/gdb.fortran/module_declarations.f90
new file mode 100644
index 00000000000..314e2405b34
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/module_declarations.f90
@@ -0,0 +1,59 @@
+! Copyright 2026 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/>.
+
+module mod1
+  implicit none
+  integer :: var_i = 1
+  integer :: global_var = 100
+end module mod1
+
+module mod2
+  implicit none
+  integer :: var_i = 2
+end module mod2
+
+subroutine sub1
+  use mod1, var_i_alias=>var_i
+  use mod2
+  implicit none
+  var_i_alias = 3
+  var_i = 4
+end subroutine  ! bp-sub1
+
+subroutine sub2
+  use mod1
+  use mod2, var_i_alias=>var_i
+  implicit none
+  var_i_alias = 23
+  var_i = 25
+end subroutine ! bp-sub2
+
+subroutine sub3
+  use mod1, var_i_from_mod1=>var_i
+  use mod2, var_i_from_mod2=>var_i
+  implicit none
+  var_i_from_mod1 = 31
+  var_i_from_mod2 = 32
+end subroutine ! bp-sub3
+
+program main
+  use mod1, global_alias=>global_var, global_var_i_from_mod1=>var_i
+  implicit none
+  global_alias = 200
+  global_var_i_from_mod1 = 300
+  call sub1  ! bp-main
+  call sub2
+  call sub3
+end