Fix off-by one comparison bug in comparing function parameters

* src/abg-comparison.cc
	(function_decl_diff::ensure_lookup_tables_populated): Function
	parameters that are diff'ed start at the first non-implicit
	parameter, not at the first parameter.  Oops.
	* tests/data/test-diff-dwarf/test3-v0.o: New test input binary.
	* tests/data/test-diff-dwarf/test3-v0.cc: Source code for the
	binary above.
	* tests/data/test-diff-dwarf/test3-v1.o: New test input binary.
	* tests/data/test-diff-dwarf/test3-v1.cc: Source code for the
	binary above.
	* tests/data/test-diff-dwarf/test3-report.txt: Reference report
	for the diff of the new test inputs.
	* tests/test-diff-dwarf.cc: Use the test inputs above to run new
	tests.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>

src/abg-comparison.cc

@@ -4353,7 +4353,8 @@ function_decl_diff::ensure_lookup_tables_populated()
        i != priv_->parm_changes_.deletions().end();
        ++i)
     {
-      parm = deleted_parameter_at(i->index());
+      parm = *(first_function_decl()->get_first_non_implicit_parm()
+	       + i->index());
       parm_name = parm->get_name_id();
       // If for a reason the type name is empty we want to know and
       // fix that.
@@ -4372,7 +4373,7 @@ function_decl_diff::ensure_lookup_tables_populated()
 	   j != i->inserted_indexes().end();
 	   ++j)
 	{
-	  parm = inserted_parameter_at(*j);
+	  parm = *(second_function_decl()->get_first_non_implicit_parm() + *j);
 	  parm_name = parm->get_name_id();
 	  // If for a reason the type name is empty we want to know and
 	  // fix that.

tests/data/test-diff-dwarf/test3-report.txt

@@ -0,0 +1,13 @@
+Functions changes summary: 0 Removed, 1 Changed, 0 Added function
+Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
+
+1 function with some indirect sub-type change:
+
+  [C]'method void C1::foo(C0&)' has some indirect sub-type changes:
+    parameter 1 of type 'C0&' has sub-type changes:
+      in referenced type 'struct C0':
+        size changed from 32 to 64 bits
+        1 data member insertion:
+          'char C0::m1', at offset 32 (in bits)
+
+

tests/data/test-diff-dwarf/test3-v0.cc

@@ -0,0 +1,19 @@
+struct C0
+{
+  typedef int Int;
+  Int m0;
+
+  C0()
+    :m0(0)
+  {}
+ };
+
+struct C1
+{
+  void
+  foo(C0&);
+};
+
+void
+C1::foo(C0&)
+{}

tests/data/test-diff-dwarf/test3-v1.cc

@@ -0,0 +1,21 @@
+struct C0
+{
+  typedef int Int;
+  Int m0;
+  char m1;
+
+  C0()
+    :m0(0),
+     m1(0)
+  {}
+ };
+
+struct C1
+{
+  void
+  foo(C0&);
+};
+
+void
+C1::foo(C0&)
+{}

tests/test-diff-dwarf.cc

@@ -74,6 +74,12 @@ InOutSpec in_out_specs[] =
     "data/test-diff-dwarf/test2-report.txt",
     "output/test-diff-dwarf/test2-report.txt"
   },
+  {
+    "data/test-diff-dwarf/test3-v0.o",
+    "data/test-diff-dwarf/test3-v1.o",
+    "data/test-diff-dwarf/test3-report.txt",
+    "output/test-diff-dwarf/test3-report.txt"
+  },
   // This should be the last entry
   {NULL, NULL, NULL, NULL}
 };