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.c (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.

(cherry picked from commit 4d82022bfd15d36717bf60a11e75e9ea02204269)

diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index 7f94796ea0105a373dcec72f9aa1109ec56a8bae..6432e82fdead003c2196887f6f336e21709a7002 100644 (file)
--- a/gcc/cp/cp-gimplify.c
+++ b/gcc/cp/cp-gimplify.c
@@ -1590,6 +1590,8 @@ 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_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 (file)
index 0000000..59ed524
--- /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;
+}