[Bug translator/17959] New: Something (broken DWARF?) causes Systemtap to generate C code with uint0_t types

[Bug translator/17959] New: Something (broken DWARF?) causes Systemtap to generate C code with uint0_t types

[aram.h at mgk dot ro]

https://sourceware.org/bugzilla/show_bug.cgi?id=17959

            Bug ID: 17959
           Summary: Something (broken DWARF?) causes Systemtap to generate
                    C code with uint0_t types
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: translator
          Assignee: systemtap at sourceware dot org
          Reporter: aram.h at mgk dot ro
                CC: mjw at redhat dot com

When using systemtap on Go binaries that work around issue 17957 and 17958,
systemtap will fail to create the kernel module because the generated C code
uses uint0_t types:

/tmp/stapUOqJjk/stap_ea1e3b08acea61492ed2615b6f549cbe_535512_src.c: In function
‘function__dwarf_tvar_get__p__261’:
/tmp/stapUOqJjk/stap_ea1e3b08acea61492ed2615b6f549cbe_535512_src.c:12640:7:
error: unknown type name ‘uint0_t’
     { uint0_t value = deref (sizeof addr, addr); addr = value; }
       ^
/tmp/stapUOqJjk/stap_ea1e3b08acea61492ed2615b6f549cbe_535512_src.c: In function
‘function__dwarf_tvar_get__p__585’:
/tmp/stapUOqJjk/stap_ea1e3b08acea61492ed2615b6f549cbe_535512_src.c:12712:7:
error: unknown type name ‘uint0_t’
     { uint0_t value = deref (sizeof addr, addr); addr = value; }
       ^
/tmp/stapUOqJjk/stap_ea1e3b08acea61492ed2615b6f549cbe_535512_src.c: In function
‘function__dwarf_tvar_get_addr_647’:
/tmp/stapUOqJjk/stap_ea1e3b08acea61492ed2615b6f549cbe_535512_src.c:13060:7:
error: unknown type name ‘uint0_t’
     { uint0_t value = deref (sizeof addr, addr); addr = value; }
       ^

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[Bug translator/17959] Something (broken DWARF?) causes Systemtap to generate C code with uint0_t types

[aram.h at mgk dot ro]

https://sourceware.org/bugzilla/show_bug.cgi?id=17959

Aram Hăvărneanu <aram.h at mgk dot ro> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aram.h at mgk dot ro

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[Bug translator/17959] Something (broken DWARF?) causes Systemtap to generate C code with uint0_t types

[aram.h at mgk dot ro]

https://sourceware.org/bugzilla/show_bug.cgi?id=17959

--- Comment #1 from Aram Hăvărneanu <aram.h at mgk dot ro> ---
Created attachment 8122
  --> https://sourceware.org/bugzilla/attachment.cgi?id=8122&action=edit
Generated src.c.

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[Bug translator/17959] Something (broken DWARF?) causes Systemtap to generate C code with uint0_t types

[aram.h at mgk dot ro]

https://sourceware.org/bugzilla/show_bug.cgi?id=17959

--- Comment #2 from Aram Hăvărneanu <aram.h at mgk dot ro> ---
Added generated src.c.

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[Bug translator/17959] Something (broken DWARF?) causes Systemtap to generate C code with uint0_t types

[mjw at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17959

--- Comment #3 from Mark Wielaard <mjw at redhat dot com> ---
This seems to be caused by a "sizeless" pointer type.

The following quick hack seems to solve the issue:

diff --git a/loc2c.c b/loc2c.c
index aef999c..b179240 100644
--- a/loc2c.c
+++ b/loc2c.c
@@ -2132,7 +2132,7 @@ c_translate_pointer (struct obstack *pool, int indent,
   Dwarf_Attribute attr_mem;
   Dwarf_Word byte_size;
   if (dwarf_attr_integrate (typedie, DW_AT_byte_size, &attr_mem) == NULL)
-    byte_size = 0;
+    byte_size = max_fetch_size (*input, typedie);
   else if (dwarf_formudata (&attr_mem, &byte_size) != 0)
     FAIL (*input,
          N_("cannot get byte_size attribute for type %s: %s"),

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[Bug translator/17959] Something (broken DWARF?) causes Systemtap to generate C code with uint0_t types

[mjw at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17959

Mark Wielaard <mjw at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Mark Wielaard <mjw at redhat dot com> ---
commit 4bfa7779843bda6f74c547a42a092a2974d07b9e
Author: Mark Wielaard <mjw@redhat.com>
Date:   Thu Apr 9 16:51:56 2015 +0200

    PR17959 Allow size-less pointer types.

    golang might produce a DW_TAG_pointer_type without any size. Assume
    the size of the pointer is equal to the address size of the DWARF CU
    in that case. Otherwise we might try to create values of type uint0_t.

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