[Bug 37130] New: Clang Static Analyzer: Memory Leak

https://bugs.winehq.org/show_bug.cgi?id=37130

Bug ID: 37130
           Summary: Clang Static Analyzer:  Memory Leak
           Product: Wine
           Version: 1.7.22
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]

Clang Static Analyzer identifies a potential memory leak

File: libs/wpp/ppl.yy.c

Location: line 4475, column 1

Description: Potential memory leak

static void macro_add_arg(int last)
{
  ..
  if(last || mep->args[mep->nargs-1][0])
  {
    yy_push_state(pp_macexp);
    push_buffer(NULL, NULL, NULL, last ? 2 : 1);
    ppy__scan_string(mep->args[mep->nargs-1]);
    //Clang: Calling 'ppy__scan_string'
    //Clang: Returned allocated memory
  }
    //Clang: Potential memory leak
}

The pyy__scan_string function has a non-used return value. Calling this
function will anyway make the malloc() function return the value, and after it
is called, memory must be freed.

Let's see how the call of the pyy__scan_string function leads to calling
malloc.

YY_BUFFER_STATE ppy__scan_string (yyconst char * yystr )
{
  return ppy__scan_bytes(yystr,strlen(yystr) );
}

YY_BUFFER_STATE ppy__scan_bytes  (yyconst char * yybytes,
                                  yy_size_t  _yybytes_len )
{
  YY_BUFFER_STATE b;
  char *buf;
  ...
  buf = (char *) ppy_alloc(n  );
  ...
  b = ppy__scan_buffer(buf,n );
  ...
  return b;
}

YY_BUFFER_STATE ppy__scan_buffer  (char * base, yy_size_t size )
{
  YY_BUFFER_STATE b;
    ...
  b=(YY_BUFFER_STATE) ppy_alloc(sizeof(struct yy_buffer_state));
  ...
  return b;
}

void *ppy_alloc (yy_size_t  size )
{
  return (void *) malloc( size );
}