Re: [committed mig] Do not generate code dereferencing type-punned pointers

[David Michael]

On Sun, Feb 15, 2015 at 11:09 AM, Justus Winter
<4winter@informatik.uni-hamburg.de> wrote:
> * utils.c (WriteFieldDeclPrim): Generate a union with an additional
> pointer field for variable-length arrays.

This makes GDB's awk script go haywire because it doesn't know how to
deal with unions.  The following is a workaround to get it building
again, but I'm not sure of its correctness.  Can someone more
knowledgeable than me check on this?

Thanks.

David

--- gdb/reply_mig_hack.awk
+++ gdb/reply_mig_hack.awk
@@ -68,6 +68,11 @@
   print; next;
 }

+parse_phase == 4 && /^[ \t]*union {/ {
+  parse_phase = 4.5;
+  print; next;
+}
+
 parse_phase == 4 {
   # The value field for an argument.
   arg_name[num_args] = $2;
@@ -78,6 +83,22 @@
   print; next;
 }

+parse_phase == 4.5 {
+  arg_name[num_args] = $2;
+  sub (/[][0-9;]*$/, "", arg_name[num_args]);
+  arg_type[num_args] = "data_t";
+  arg_name[num_args + 1] = arg_name[num_args] "Cnt";
+  arg_type[num_args + 1] = "mach_msg_type_number_t";
+  num_args += 2;
+  parse_phase = 4.6;
+  print; next;
+}
+
+parse_phase == 4.6 && /}/ {
+  parse_phase = 3;
+  print; next;
+}
+
 parse_phase == 5 && /^[ \t]*(auto |static |)const mach_msg_type_t/ {
   # The type check structure for an argument.
   arg_check_name[num_checks] = $(NF - 2);