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Tighten up parsing logic in gen_node_support.pl.

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Teach this script to handle function pointer fields honestly.
Previously they were just silently ignored, but that's not likely to
be a behavior we can accept indefinitely.  This mostly entails fixing
it so that a field declaration spanning multiple lines can be parsed,
because we have a bunch of such fields that're laid out that way.
But that's a good improvement in its own right.

With that change and a minor regex adjustment, the only struct it
fails to parse in the node-defining headers is A_Const, because
of the embedded union.  The path of least resistance is to move
that union declaration outside the struct.

Having done those things, we can make it error out if it finds
any within-struct syntax it doesn't understand, which seems like
a pretty important property for robustness.

This commit doesn't change the output files at all; it's just in
the way of future-proofing.

Discussion: https://postgr.es/m/2593369.1657759779@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2022-07-14 09:04:23 -04:00
parent 5794491058
commit 7c0eb3c622
3 changed files with 90 additions and 20 deletions
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77
src/backend/nodes/gen_node_support.pl
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@@ -213,15 +213,39 @@ foreach my $infile (@ARGV)
}
$file_content .= $raw_file_content;
my $lineno = 0;
my $lineno = 0;
my $prevline = '';
foreach my $line (split /\n/, $file_content)
{
# per-physical-line processing
$lineno++;
chomp $line;
$line =~ s/\s*$//;
next if $line eq '';
next if $line =~ /^#(define|ifdef|endif)/;
# within a struct, don't process until we have whole logical line
if ($in_struct && $subline > 0)
{
if ($line =~ /;$/)
{
# found the end, re-attach any previous line(s)
$line = $prevline . $line;
$prevline = '';
}
elsif ($prevline eq ''
&& $line =~ /^\s*pg_node_attr\(([\w(), ]*)\)$/)
{
# special case: node-attributes line doesn't end with semi
}
else
{
# set it aside for a moment
$prevline .= $line . ' ';
next;
}
}
# we are analyzing a struct definition
if ($in_struct)
{
@@ -394,7 +418,7 @@ foreach my $infile (@ARGV)
}
# normal struct field
elsif ($line =~
/^\s*(.+)\s*\b(\w+)(\[\w+\])?\s*(?:pg_node_attr\(([\w(), ]*)\))?;/
/^\s*(.+)\s*\b(\w+)(\[[\w\s+]+\])?\s*(?:pg_node_attr\(([\w(), ]*)\))?;/
)
{
if ($is_node_struct)
@@ -441,13 +465,46 @@ foreach my $infile (@ARGV)
$my_field_attrs{$name} = \@attrs;
}
}
else
# function pointer field
elsif ($line =~
/^\s*([\w\s*]+)\s*\(\*(\w+)\)\s*\((.*)\)\s*(?:pg_node_attr\(([\w(), ]*)\))?;/
)
{
if ($is_node_struct)
{
#warn "$infile:$lineno: could not parse \"$line\"\n";
my $type = $1;
my $name = $2;
my $args = $3;
my $attrs = $4;
my @attrs;
if ($attrs)
{
@attrs = split /,\s*/, $attrs;
foreach my $attr (@attrs)
{
if ( $attr !~ /^copy_as\(\w+\)$/
&& $attr !~ /^read_as\(\w+\)$/
&& !elem $attr,
qw(equal_ignore read_write_ignore))
{
die
"$infile:$lineno: unrecognized attribute \"$attr\"\n";
}
}
}
push @my_fields, $name;
$my_field_types{$name} = 'function pointer';
$my_field_attrs{$name} = \@attrs;
}
}
else
{
# We're not too picky about what's outside structs,
# but we'd better understand everything inside.
die "$infile:$lineno: could not parse \"$line\"\n";
}
}
# not in a struct
else
@@ -709,6 +766,12 @@ _equal${n}(const $n *a, const $n *b)
unless $equal_ignore;
}
}
elsif ($t eq 'function pointer')
{
# we can copy and compare as a scalar
print $cff "\tCOPY_SCALAR_FIELD($f);\n" unless $copy_ignore;
print $eff "\tCOMPARE_SCALAR_FIELD($f);\n" unless $equal_ignore;
}
# node type
elsif ($t =~ /(\w+)\*/ and elem $1, @node_types)
{
@@ -980,6 +1043,12 @@ _read${n}(void)
unless $no_read;
}
}
elsif ($t eq 'function pointer')
{
# We don't print these, and we can't read them either
die "cannot read function pointer in struct \"$n\" field \"$f\"\n"
unless $no_read;
}
# Special treatments of several Path node fields
elsif ($t eq 'RelOptInfo*' && elem 'write_only_relids', @a)
{