gcc 4.9.2 parse question -- how to build a call expression

[Dinh Le <dinh@xxxxxxxx>]

Hi,

I manually add the call_expr statement

    sqlite3_prepare_v2 (sqldb0, sql, tlen, stmt, 0);

into the parse tree using the following code:

    fn = lookup_name (get_identifier ("sqlite3_prepare_v2"));
    argarr[0] = lookup_name (get_identifier ("db"));
    argarr[1] = lookup_name (get_identifier ("sql"));
    argarr[2] = lookup_name (get_identifier ("len"));
    argarr[3] = lookup_name (get_identifier ("stmt"));
    argarr[4] = null_pointer_node;
    check_function_arguments (TREE_TYPE (fn), 5, argarr);
    stmt = build_call_expr_loc_array (input_location, fn, 5, argarr);
    add_stmt (stmt);

where the variables were declared as:

    struct sqlite3 *db;
    char *sql = "SELECT name FROM plist";
    int len = strlen(sql)+1;
    struct sqlite3_stmt **stmt;

My program compiled successfully but generated segmentation fault
at sqlite3_prepare_v2 because the parameters received there are not
correctly aligned as shown by GDB below

    Starting program: /home/dinh/SRC/SAMPLES/a.out
    [Thread debugging using libthread_db enabled]
    Using host libthread_db library 
"/lib/x86_64-linux-gnu/libthread_db.so.1".

    Program received signal SIGSEGV, Segmentation fault.
    0x00007ffff7b66bde in sqlite3LockAndPrepare (db=0x601078,
        zSql=0x1e <error: Cannot access memory at address 0x1e>, 
nBytes=-8848,
        saveSqlFlag=1, pOld=0x0, ppStmt=0x0, pzTail=0x601078) at 
sqlite3.c:105117
    105117      *ppStmt = 0;
    (gdb) bt
    #0  0x00007ffff7b66bde in sqlite3LockAndPrepare (db=0x601078,
        zSql=0x1e <error: Cannot access memory at address 0x1e>, 
nBytes=-8848,
        saveSqlFlag=1, pOld=0x0, ppStmt=0x0, pzTail=0x601078) at 
sqlite3.c:105117
    #1  0x00007ffff7b66e1a in sqlite3_prepare_v2 (db=0x601078,
        zSql=0x1e <error: Cannot access memory at address 0x1e>, 
nBytes=-8848,
        ppStmt=0x0, pzTail=0x601078) at sqlite3.c:105199
    #2  0x0000000000400953 in main () at t22.c:16

The code generated by "-fdump-tree-gimple" looks fine,  In fact, I am able
to compile the (slightly modified) gimple code and run its executable
without any problem.  There are mislignment problems with the ways I
built the parse tree above.  Can some GCC expert please show me the
correct way of building a general call_expr.

Thank you much.

Dinh