[gcc r13-6419] c++, debug: Fix up locus of DW_TAG_imported_module [PR108716]

[gcc r13-6419] c++, debug: Fix up locus of DW_TAG_imported_module [PR108716]

[Jakub Jelinek]

https://gcc.gnu.org/g:4d82022bfd15d36717bf60a11e75e9ea02204269

commit r13-6419-g4d82022bfd15d36717bf60a11e75e9ea02204269
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Mar 2 19:17:52 2023 +0100

    c++, debug: Fix up locus of DW_TAG_imported_module [PR108716]
    
    Before IMPORTED_DECL has been introduced in PR37410, we used to emit correct
    DW_AT_decl_line on DW_TAG_imported_module on the testcase below, after that
    change we haven't emitted it at all for a while and after some time
    started emitting incorrect locus, in particular the location of } closing
    the function.
    
    The problem is that while we have correct EXPR_LOCATION on the USING_STMT,
    when genericizing that USING_STMT into IMPORTED_DECL we don't copy the
    location to DECL_SOURCE_LOCATION, so it gets whatever input_location happens
    to be when it is created.
    
    2023-03-02  Jakub Jelinek  <jakub@redhat.com>
    
            PR debug/108716
            * cp-gimplify.cc (cp_genericize_r) <case USING_STMT>: Set
            DECL_SOURCE_LOCATION on IMPORTED_DECL to expression location
            of USING_STMT or input_location.
    
            * g++.dg/debug/dwarf2/pr108716.C: New test.

Diff:
---
 gcc/cp/cp-gimplify.cc                        |  2 ++
 gcc/testsuite/g++.dg/debug/dwarf2/pr108716.C | 14 ++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index 32fe53521cc..921b0e4b120 100644
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -1530,6 +1530,8 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
 		tree using_directive = make_node (IMPORTED_DECL);
 		TREE_TYPE (using_directive) = void_type_node;
 		DECL_CONTEXT (using_directive) = current_function_decl;
+		DECL_SOURCE_LOCATION (using_directive)
+		  = cp_expr_loc_or_input_loc (stmt);
 
 		IMPORTED_DECL_ASSOCIATED_DECL (using_directive) = decl;
 		DECL_CHAIN (using_directive) = BLOCK_VARS (block);
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/pr108716.C b/gcc/testsuite/g++.dg/debug/dwarf2/pr108716.C
new file mode 100644
index 00000000000..59ed52424da
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/pr108716.C
@@ -0,0 +1,14 @@
+// PR debug/108716
+// { dg-options "-O0 -gdwarf-5 -dA -fno-merge-debug-strings" }
+// { dg-final { scan-assembler "DIE \\(\[^\n\r\]*\\) DW_TAG_imported_module\[^\n\r\]*\[\n\r]*\[^\n\r\]* DW_AT_decl_file\[^\n\r\]*\[\n\r]*\[^\n\r\]*0xc\[^\n\r\]* DW_AT_decl_line\[^\n\r\]*\[\n\r]*(\[^\n\r\]*0x13\[^\n\r\]* DW_AT_decl_column\[^\n\r\]*\[\n\r]*)?" } }
+
+namespace M {
+  int x = 1;
+}
+
+int
+main ()
+{
+  using namespace M;
+  return 0;
+}