[PATCH] Fix PR87443, bogus/missing DW_AT_abstract_origins

[Richard Biener]

This fixes mentioned PR (I should stop looking at generated debug
info...) where it notes that concrete inline instance DW_TAG_lexical_block
miss DW_AT_abstract_origin attributes pointing to the abstract instance
and that inline instances of DW_TAG_lexical_block have 
DW_AT_abstract_origins pointing to other inline or concrete instances
rather than the abstract instance.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

I even added a testcase.  Yay.

OK?

Thanks,
Richard.

2018-09-26  Richard Biener  <rguent...@suse.de>

        PR debug/87443
        * dwarf2out.c (gen_lexical_block_die): Do not equate inline
        or concrete instance DIE to the tree.  Create abstract origin
        attributes also for concrete instances.

        * gcc.dg/debug/dwarf2/inline5.c: New testcase.

Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c     (revision 264594)
+++ gcc/dwarf2out.c     (working copy)
@@ -24091,18 +24091,16 @@ gen_lexical_block_die (tree stmt, dw_die
     }
   else if (BLOCK_ABSTRACT_ORIGIN (stmt))
     {
-      /* If this is an inlined instance, create a new lexical die for
-        anything below to attach DW_AT_abstract_origin to.  */
+      /* If this is an inlined or conrecte instance, create a new lexical
+        die for anything below to attach DW_AT_abstract_origin to.  */
       if (old_die)
-       {
-         stmt_die = new_die (DW_TAG_lexical_block, context_die, stmt);
-         equate_block_to_die (stmt, stmt_die);
-         old_die = NULL;
-       }
+       stmt_die = new_die (DW_TAG_lexical_block, context_die, stmt);
 
       tree origin = block_ultimate_origin (stmt);
-      if (origin != NULL_TREE && origin != stmt)
+      if (origin != NULL_TREE && (origin != stmt || old_die))
        add_abstract_origin_attribute (stmt_die, origin);
+
+      old_die = NULL;
     }
 
   if (old_die)

Index: gcc/testsuite/gcc.dg/debug/dwarf2/inline5.c
===================================================================
--- gcc/testsuite/gcc.dg/debug/dwarf2/inline5.c (nonexistent)
+++ gcc/testsuite/gcc.dg/debug/dwarf2/inline5.c (working copy)
@@ -0,0 +1,26 @@
+/* Verify that the concrete instance DW_TAG_lexical_block has an abstract
+   origin.  Verify that the inline instance has the abstract instance as
+   abstract origin rather than the concrete one.  */
+/* { dg-options "-O -gdwarf -dA" } */
+/* { dg-do compile } */
+/* { dg-final { scan-assembler-times "DW_TAG_inlined_subroutine" 2 } } */
+/* { dg-final { scan-assembler-times "DW_TAG_lexical_block\\)\[^#\]*# 
DW_AT_abstract_origin" 2 } } */
+/* { dg-final { scan-assembler-times "DW_TAG_lexical_block\\)\[^#\]*# \\(DIE 
\\(0x\[0-9a-f\]*\\) DW_TAG_variable" 1 } } */
+/* We do not know which is output first so look for both invalid abstract
+   origins on the lexical blocks (knowing that the abstract instance has
+   no attribute following the DW_TAG_lexical_block.  */
+/* { dg-final { scan-assembler-not "\\(DIE \\(0x(\[0-9a-f\]*)\\) 
DW_TAG_lexical_block\\)\[^#\]*# 
\[^(\].*DW_TAG_lexical_block\\)\[^#x\]*x\\1\[^#\]*# DW_AT_abstract_origin" } } 
*/
+/* { dg-final { scan-assembler-not 
"DW_TAG_lexical_block\\)\[^#x\]*x(\[0-9a-f\]*)\[^#\]*# 
DW_AT_abstract_origin.*\\(DIE \\(0x\\1\\) DW_TAG_lexical_block\\)\[^#\]*# 
DW_AT" } } */
+
+int foo (int i)
+{
+    {
+      volatile int j = i + 3;
+      return j - 2;
+    }
+}
+int main()
+{
+  volatile int z = foo (-1);
+  return z;
+}