[RFA, patch] Add missing source location info to thunks

[Cary Coutant]

Here's a revised patch, with testcase added, and with Steven's
suggested change...

-cary


2012-08-06  Cary Coutant  <ccoutant@google.com>

gcc/
	* cgraphunit.c (assemble_thunk): Add source line info.
	* final.c (final): Check for non-null cfg pointer.
	* testsuite/g++.dg/debug/dwarf2/non-virtual-thunk.C: New test case.


commit db557f2dabd9658e59a5111dd156aa39d691bf22
Author: Cary Coutant <ccoutant@google.com>
Date:   Mon Aug 6 12:48:31 2012 -0700

    Add line number info for thunks; fix an ICE when -dA used with thunks.

    gcc/
        * cgraphunit.c (assemble_thunk): Add source line info.
        * final.c (final): Check for non-null cfg pointer.
        * testsuite/g++.dg/debug/dwarf2/non-virtual-thunk.C: New test case.


diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index a6591b5..2dd0871 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -1381,6 +1381,10 @@ assemble_thunk (struct cgraph_node *node)
       init_function_start (thunk_fndecl);
       cfun->is_thunk = 1;
       assemble_start_function (thunk_fndecl, fnname);
+      (*debug_hooks->source_line) (DECL_SOURCE_LINE (thunk_fndecl),
+                                  DECL_SOURCE_FILE (thunk_fndecl),
+                                  /* discriminator */ 0,
+                                  /* is_stmt */ 1);

       targetm.asm_out.output_mi_thunk (asm_out_file, thunk_fndecl,
                                       fixed_offset, virtual_value, alias);
diff --git a/gcc/final.c b/gcc/final.c
index cdae011..30890b3 100644
--- a/gcc/final.c
+++ b/gcc/final.c
@@ -1863,11 +1863,13 @@ final (rtx first, FILE *file, int optimize_p)
       start_to_bb = XCNEWVEC (basic_block, bb_map_size);
       end_to_bb = XCNEWVEC (basic_block, bb_map_size);

-      FOR_EACH_BB_REVERSE (bb)
-       {
-         start_to_bb[INSN_UID (BB_HEAD (bb))] = bb;
-         end_to_bb[INSN_UID (BB_END (bb))] = bb;
-       }
+      /* There is no cfg for a thunk.  */
+      if (!cfun->is_thunk)
+       FOR_EACH_BB_REVERSE (bb)
+         {
+           start_to_bb[INSN_UID (BB_HEAD (bb))] = bb;
+           end_to_bb[INSN_UID (BB_END (bb))] = bb;
+         }
     }

   /* Output the insns.  */
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/non-virtual-thunk.C
b/gcc/testsuite/g++.dg/debug/dwar
new file mode 100644
index 0000000..8ad347a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/non-virtual-thunk.C
@@ -0,0 +1,39 @@
+// { dg-do compile }
+// { dg-options "-g2 -dA" }
+
+// Verify that line number info is output for the non-virtual
+// thunks for C::~C().
+// { dg-final { scan-assembler "thunk.C:30" } }
+
+class A
+{
+ public:
+  A();
+  virtual ~A();
+ private:
+  int i;
+};
+
+class B
+{
+ public:
+  B();
+  virtual ~B();
+ private:
+  int i;
+};
+
+class C : public A, public B
+{
+ public:
+  C();
+  virtual ~C(); // line 30
+};
+
+C::C()
+{
+}
+
+C::~C()
+{
+}