[Bug c++/56856] New: the location of -Wformat warnings point *after* the format string

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56856

             Bug #: 56856
           Summary: the location of -Wformat warnings point *after* the
                    format string
    Classification: Unclassified
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: m...@gcc.gnu.org


$ cc1plus gcc/testsuite/g++.dg/ext/builtin4.C -Wall
gcc/testsuite/g++.dg/ext/builtin4.C:9:14: warning: format ‘%d’ expects a
matching ‘int’ argument [-Wformat=]
   printf("%d");   // { dg-warning "expects a matching" }
              ^

Unfortunately, the format_tree we get at the time of the warning does not seem
to have a valid location either:

(gdb) p debug_tree(format_tree)
 <nop_expr 0x7ffff7567660
    type <pointer_type 0x7ffff741d9d8
        type <integer_type 0x7ffff741d930 char readonly string-flag QI
            size <integer_cst 0x7ffff73f7f80 constant 8>
            unit size <integer_cst 0x7ffff73f7fa0 constant 1>
            align 8 symtab 0 alias set -1 canonical type 0x7ffff741d930
precision 8 min <integer_cst 0x7ffff73f7fe0 -128> max <integer_cst
0x7ffff7414020 127>
            pointer_to_this <pointer_type 0x7ffff741d9d8>>
        unsigned SI
        size <integer_cst 0x7ffff73f7dc0 constant 32>
        unit size <integer_cst 0x7ffff73f7de0 constant 4>
        align 32 symtab 0 alias set -1 canonical type 0x7ffff741d9d8
        pointer_to_this <pointer_type 0x7ffff7420690>>
    readonly constant
    arg 0 <addr_expr 0x7ffff7567640
        type <pointer_type 0x7ffff755dbd0 type <array_type 0x7ffff755da80>
            unsigned SI size <integer_cst 0x7ffff73f7dc0 32> unit size
<integer_cst 0x7ffff73f7de0 4>
            align 32 symtab 0 alias set -1 canonical type 0x7ffff755dbd0>
        readonly constant
        arg 0 <string_cst 0x7ffff7565990 type <array_type 0x7ffff755da80>
            readonly constant static "%d\000">>>