<html>
    <head>
      <base href="http://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - incorrect dwarf information about function arguments is produced in one case"
   href="http://llvm.org/bugs/show_bug.cgi?id=15662">15662</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>incorrect dwarf information about function arguments is produced in one case
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>3.2
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>FreeBSD
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>-New Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>avg@FreeBSD.org
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=10282" name="attach_10282" title="pre-processed source code">attachment 10282</a> <a href="attachment.cgi?id=10282&action=edit" title="pre-processed source code">[details]</a></span>
pre-processed source code

Function signature in FreeBSD source code is:

void _sx_xunlock(struct sx *sx, const char *file, int line);

clang generated dwarf information (as reported by objdump -W) is:
 <1><2c70>: Abbrev Number: 55 (DW_TAG_subprogram)
  <2c71>     DW_AT_name        : (indirect string, offset: 0x1817): _sx_xunlock
  <2c75>     DW_AT_decl_file   : 1
  <2c76>     DW_AT_decl_line   : 373
  <2c78>     DW_AT_prototyped  : 1
  <2c78>     DW_AT_external    : 1
  <2c78>     DW_AT_inline      : 1      (inlined)
 <2><2c79>: Abbrev Number: 51 (DW_TAG_formal_parameter)
  <2c7a>     DW_AT_name        : (indirect string, offset: 0xd061): line
  <2c7e>     DW_AT_decl_file   : 1
  <2c7f>     DW_AT_decl_line   : 373
  <2c81>     DW_AT_type        : <a2>
 <2><2c85>: Abbrev Number: 51 (DW_TAG_formal_parameter)
  <2c86>     DW_AT_name        : (indirect string, offset: 0xd056): sx
  <2c8a>     DW_AT_decl_file   : 1
  <2c8b>     DW_AT_decl_line   : 373
  <2c8d>     DW_AT_type        : <782c>
 <2><2c91>: Abbrev Number: 51 (DW_TAG_formal_parameter)
  <2c92>     DW_AT_name        : (indirect string, offset: 0xc67): file
  <2c96>     DW_AT_decl_file   : 1
  <2c97>     DW_AT_decl_line   : 373
  <2c99>     DW_AT_type        : <32>

That is, order of arguments is recorded as 'line', 'sx', 'file'.

Please see the attached preprocessed file.
My compilation options were:
-pipe -fno-strict-aliasing -march=amdfam10 -std=c99 -g -O -Wall
-Wredundant-decls
-Wnested-externs -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith
-Winline
-Wcast-qual -Wundef -Wno-pointer-sign -fformat-extensions
-Wmissing-include-dirs
-fdiagnostics-show-option -Wno-error-tautological-compare -Wno-error-empty-body
-Wno-error-parentheses-equality -nostdinc -fno-omit-frame-pointer
-mno-omit-leaf-frame-pointer -mno-aes -mno-avx -mcmodel=kernel -mno-red-zone
-mno-mmx -mno-sse -msoft-float -fno-asynchronous-unwind-tables -ffreestanding
-fstack-protector -Werror

clang is:
FreeBSD clang version 3.2 (tags/RELEASE_32/final 170710) 20121221

The problem doesn't seem to be a common one.
Thus far, I have seen it only with this function (out of many inspected).

Please also see this thread for a preliminary discussion of this issue:
<a href="http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-April/028829.html">http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-April/028829.html</a></pre>
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