id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc,lang,patch,platform
1425,pbc_merge does not correctly adjust constant offsets for parameter names,Austin_Hastings,,"I have some PIR code (NQP generated) that contains this line:
{{{
    $P519.""new_class""(""Foo::Child"", ""Foo::Parent"" :named(""parent""))
}}}

When I dump the generated bytecode from that single file, using pbc_dump -d, I get:
{{{
 0070:  00000023 00000022                                     set_args_pc
 0076:  00000024 0000000f                                     get_results_pc
 0078:  000002c4 00000001 0000001f                            callmethodcc_p_sc
 007b:  00000026 0000000f                                     set_returns_pc
}}}

Using pbc_dump (no -d) yields:
{{{
 0070:  00000023 00000022 00000001 0000001e 00000020 00000026 00000024 0000000f 
 0078:  000002c4 00000001 0000001f 00000026 0000000f 00000020 0000030f 00000002 
}}}
Thanks to Whiteknight++, I know that the 00000020 references the String-constant-parameter-name. When I look at the dumped constants table (noting that 00000020 = 32), I find:
{{{
    # 32:
    [ 'PFC_STRING', {
        FLAGS => 0x61100 (is_string,external,live,on_free_list)
        CHARSET  => 134667160,
        SIZE     => 6,
        DATA     => ""parent""
    } ],
}}}

When I use pbc_merge to merge my bytecode file with krt0.pbc, a runtime startup file, via:
{{{
pbc_merge --output=foo.pbc library/krt0.pbc t/Pmc/Array.pbc
}}}
I dump the result and find my same code at a different offset:
{{{
 00a8:  00000023 0000003e                                     set_args_pc
 00ae:  00000024 0000002b                                     get_results_pc
 00b0:  000002c4 00000001 0000003b                            callmethodcc_p_sc
 00b3:  00000026 0000002b                                     set_returns_pc
}}}
Dumping again without -d shows:
{{{
 00a8:  00000023 0000003e 00000001 0000003a 00000020 00000042 00000024 0000002b 
 00b0:  000002c4 00000001 0000003b 00000026 0000002b 00000020 0000030f 00000002 
}}}
And I see the 4 parameter values (PMC invocant, string ""Foo::Child"", string ""parent"", string ""Foo::Parent"") but note that 2 of those values have not been changed.

The 00000001 is a P-register reference (the invocant) and I don't expect it to change. The 00000020 is an argument name, in this case a string constant, and I *do* expect it to change.

Looking in the constants table for krt0.pbc I find #27 is the highest offset (28 entries), so I would expect 32+28 = 60 to be the new offset of ""parent"" in the merged file.

In fact, going to the merged foo.pbc file, I find offset #60 contains:
{{{
    # 60:
    [ 'PFC_STRING', {
        FLAGS => 0x61100 (is_string,external,live,on_free_list)
        CHARSET  => 134667160,
        SIZE     => 6,
        DATA     => ""parent""
    } ],
}}}
exactly what I expect, but offset #32 now has:
{{{
    # 32:
    [ 'PFC_STRING', {
        FLAGS => 0x61100 (is_string,external,live,on_free_list)
        CHARSET  => 134667160,
        SIZE     => 4,
        DATA     => ""main""
    } ],
}}}

I subsequently modified the p6object code to print out the ""main"" named-parameter, and sure enough I saw ""Foo::Parent"" come out.
",bug,closed,normal,,none,2.0.0,fatal,fixed,,,,,