diff mbox

PR debug/49047 (linkage name missing for cdtors)

Message ID m3tychr05p.fsf@redhat.com
State New
Headers show

Commit Message

Dodji Seketeli May 26, 2011, 2:45 p.m. UTC 
Hello,

The constructors (resp. destructors) of a given class K are cloned.
For each constructor (resp. destructor) There is thus an abstract
version of the function and (at least) a concrete version that
actually contains the code of the abstract version.

The debug info generated for a constructor (resp. destructor) lacks
linkage name (DWARF attribute DW_AT_MIPS_linkage_name), making the job
of GDB slow and difficult when it tries to get the actual concrete
function that contains the constructor's code to, e.g, set a
breakpoint.

The patch below emits that linkage name for those concrete versions of
cloned public functions.

Tested on x86-64-unknown-linux-gnu against trunk.

gcc/

	* dwarf2out.c (gen_subprogram_die): Emit linkage name attribute
	for functions containing actual code for public cloned abstract
	functions.

gcc/testsuite/

	* g++.dg/debug/dwarf2/cdtor-1.C: New test.
---
 gcc/dwarf2out.c                             |   11 +++++++++++
 gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C |   17 +++++++++++++++++
 2 files changed, 28 insertions(+), 0 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C

Comments

Jason Merrill May 26, 2011, 3:19 p.m. UTC | #1 
Why not just call add_linkage_name after add_abstract_origin_attribute?

Jason
diff mbox

Patch

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 55453a3..85c01b1 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -19601,6 +19601,7 @@  gen_subprogram_die (tree decl, dw_die_ref context_die)
   dw_die_ref old_die = lookup_decl_die (decl);
   int declaration = (current_function_decl != decl
 		     || class_or_namespace_scope_p (context_die));
+  bool fn_has_code_addr_p = false;
 
   premark_used_types ();
 
@@ -19769,6 +19770,7 @@  gen_subprogram_die (tree decl, dw_die_ref context_die)
 	      /* We have already generated the labels.  */
 	      add_AT_lbl_id (subr_die, DW_AT_low_pc, fde->dw_fde_begin);
 	      add_AT_lbl_id (subr_die, DW_AT_high_pc, fde->dw_fde_end);
+	      fn_has_code_addr_p = true;
 	    }
 	  else
 	    {
@@ -19780,6 +19782,7 @@  gen_subprogram_die (tree decl, dw_die_ref context_die)
 	      ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_END_LABEL,
 					   current_function_funcdef_no);
 	      add_AT_lbl_id (subr_die, DW_AT_high_pc, label_id);
+	      fn_has_code_addr_p = true;
 	    }
 
 #if VMS_DEBUGGING_INFO
@@ -19929,6 +19932,14 @@  gen_subprogram_die (tree decl, dw_die_ref context_die)
       if (cfun->static_chain_decl)
 	add_AT_location_description (subr_die, DW_AT_static_link,
 		 loc_list_from_tree (cfun->static_chain_decl, 2));
+
+      if (fn_has_code_addr_p && origin && TREE_PUBLIC (origin))
+	/*  So this is where the actual code for a publicly accessible
+	    cloned function is.  Let's emit linkage name attribute for
+	    it.  This helps debuggers to e.g, set breakpoints into
+	    constructors/destructors when the user asks "break
+	    K::K".  */
+	add_linkage_name (subr_die, decl);
     }
 
   /* Generate child dies for template paramaters.  */
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C
new file mode 100644
index 0000000..6d39e54
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C
@@ -0,0 +1,17 @@ 
+// origin PR debug/49047
+// { dg-options "-g -dA" }
+// { dg-do compile }
+
+struct K
+{
+  K () { }
+  ~K () { }
+};
+
+int
+main()
+{
+    K k;
+}
+
+// { dg-final {scan-assembler-times "\[^\n\r\]*DW_AT_MIPS_linkage_name:" 2 } }