Patchwork PING^2: [patch] pr/54508: fix incomplete debug information for class

login
register
mail settings
Submitter Paul Koning
Date Oct. 4, 2012, 4:09 p.m.
Message ID <C75A84166056C94F84D238A44AF9F6AD243D5E@AUSX10MPS303.AMER.DELL.COM>
Download mbox | patch
Permalink /patch/189202/
State New
Headers show

Comments

Paul Koning - Oct. 4, 2012, 4:09 p.m.
Ping ^ 2...

------

If the only reference in a source file is to a static method of a class, then GCC would output debug information for the class name but not any of its members or base classes.  The attached patch fixes this by having "prune_unused_types_mark" mark all of the parent's children if the parent DIE type is for a class.

The associated new testcase verifies this, and also verifies this that references to a function in a namespace do *not* cause other parts of that namespace to be emitted as debug information, but that references to a method in a class (or struct or union) do emit the other information for that class.

Checked by "make check" on dwarf2.exp.

Ok to commit?  This would close PR/54508.

	paul

ChangeLog:

2012-09-17  Paul Koning  <ni1d@arrl.net>

	* dwarf2out.c (prune_unused_types_mark): Mark all of parent's
	children if parent is a class.

testsuite/ChangeLog:

2012-09-17  Paul Koning  <ni1d@arrl.net>

	* g++.dg/debug/dwarf2/pr54508.C: New.
Cary Coutant - Oct. 4, 2012, 5:38 p.m.
>       /* We also have to mark its parents as used.
> -        (But we don't want to mark our parents' kids due to this.)  */
> +        (But we don't want to mark our parent's kids due to this,
> +        unless it is a class.)  */
>       if (die->die_parent)
> -       prune_unused_types_mark (die->die_parent, 0);
> +       prune_unused_types_mark (die->die_parent,
> +                                (die->die_parent->die_tag == DW_TAG_class_type ||
> +                                 die->die_parent->die_tag == DW_TAG_structure_type ||
> +                                 die->die_parent->die_tag == DW_TAG_union_type));

I'd suggest replacing these conditions with a call to class_scope_p().
That will also cover DW_TAG_interface_type, which might be irrelevant
for this particular case, but is probably good to cover in the general
case.

-cary
Paul Koning - Oct. 4, 2012, 8 p.m.
On Oct 4, 2012, at 12:09 PM, <Paul_Koning@Dell.com>
 <Paul_Koning@Dell.com> wrote:

> Ping ^ 2...
> 
> ------
> 
> If the only reference in a source file is to a static method of a class, then GCC would output debug information for the class name but not any of its members or base classes.  The attached patch fixes this by having "prune_unused_types_mark" mark all of the parent's children if the parent DIE type is for a class.
> 
> The associated new testcase verifies this, and also verifies this that references to a function in a namespace do *not* cause other parts of that namespace to be emitted as debug information, but that references to a method in a class (or struct or union) do emit the other information for that class.
> 
> Checked by "make check" on dwarf2.exp.

My apologies -- I missed something when I did that check.  Some existing testcases need to be adjusted to match.  Updated patch coming shortly.

	paul

Patch

Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c	(revision 191408)
+++ gcc/dwarf2out.c	(working copy)
@@ -21033,9 +21033,13 @@ 
      prune_unused_types_mark_generic_parms_dies (die);

      /* We also have to mark its parents as used.
-	 (But we don't want to mark our parents' kids due to this.)  */
+	 (But we don't want to mark our parent's kids due to this,
+	 unless it is a class.)  */
      if (die->die_parent)
-	prune_unused_types_mark (die->die_parent, 0);
+	prune_unused_types_mark (die->die_parent, 
+				 (die->die_parent->die_tag == DW_TAG_class_type ||
+				  die->die_parent->die_tag == DW_TAG_structure_type ||
+				  die->die_parent->die_tag == DW_TAG_union_type));

      /* Mark any referenced nodes.  */
      prune_unused_types_walk_attribs (die);
Index: testsuite/g++.dg/debug/dwarf2/pr54508.C
===================================================================
--- testsuite/g++.dg/debug/dwarf2/pr54508.C	(revision 0)
+++ testsuite/g++.dg/debug/dwarf2/pr54508.C	(revision 0)
@@ -0,0 +1,67 @@ 
+// PR debug/54508
+// { dg-do compile }
+// { dg-options "-g2 -dA" }
+
+// { dg-final { scan-assembler "\"cbase\\\\0\"\[ \t\]+\[#;/!|@\]+ DW_AT_name\|DW_AT_name: \"cbase\"" } }
+// { dg-final { scan-assembler "\"OPCODE\\\\0\"\[ \t\]+\[#;/!|@\]+ DW_AT_name\|DW_AT_name: \"OPCODE\"" } }
+// { dg-final { scan-assembler "\"bi\\\\0\"\[ \t\]+\[#;/!|@\]+ DW_AT_name" } }
+// { dg-final { scan-assembler "\"si\\\\0\"\[ \t\]+\[#;/!|@\]+ DW_AT_name" } }
+// { dg-final { scan-assembler "\"f1\\\\0\"\[ \t\]+\[#;/!|@\]+ DW_AT_name" } }
+// { dg-final { scan-assembler "\"f2\\\\0\"\[ \t\]+\[#;/!|@\]+ DW_AT_name" } }
+// { dg-final { scan-assembler-not "\"nc\\\\0\"\[ \t\]+\# DW_AT_name\|DW_AT_name: \"nc\"" } }
+
+class cbase
+
+{
+public:
+ static int si;
+    int bi;
+};
+
+class c : public cbase
+
+{
+public:
+ enum
+ {
+  OPCODE = 251
+ };
+ int i ;
+ static const char *testc (void) { return "foo"; }
+};
+
+struct s
+{
+    int f1;
+    static const char *tests (void) { return "test"; }
+};
+
+union u
+{
+    int f2;
+    double d;
+    static const char *testu (void) { return "test union"; }
+};
+
+namespace n 
+{
+    const char *ntest (void) { return "test n"; }
+
+    class nc
+    {
+    public:
+        int i;
+        static int sj;
+    };
+}
+
+extern void send (int, int, const void *, int);
+
+void test (int src)
+{
+  int cookie = 1;
+  send(src, c::OPCODE, c::testc (), cookie);
+  send(src, c::OPCODE, s::tests (), cookie);
+  send(src, c::OPCODE, u::testu (), cookie);
+  send(src, c::OPCODE, n::ntest (), cookie);
+}