Tighten up parsing logic in gen_node_support.pl.

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

diff --git a/src/backend/nodes/gen_node_support.pl b/src/backend/nodes/gen_node_support.pl
index 96af17516aa7701f776a66402d15a57d058b8bc7..975e456ee2dfef63ed863f8ba2418d9ea5190db0 100644 (file)
--- a/src/backend/nodes/gen_node_support.pl
+++ b/src/backend/nodes/gen_node_support.pl
@@ -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)
        {

diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index b0c9c5f2ef67d6d5505ca63c74b9bdd63c527371..98fe1abaa28a89bcd48715e148ab64e5be6d4ebe 100644 (file)
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -303,26 +303,26 @@ typedef struct A_Expr
 
 /*
  * A_Const - a literal constant
+ *
+ * Value nodes are inline for performance.  You can treat 'val' as a node,
+ * as in IsA(&val, Integer).  'val' is not valid if isnull is true.
  */
+union ValUnion
+{
+   Node        node;
+   Integer     ival;
+   Float       fval;
+   Boolean     boolval;
+   String      sval;
+   BitString   bsval;
+};
+
 typedef struct A_Const
 {
    pg_node_attr(custom_copy_equal, custom_read_write, no_read)
 
    NodeTag     type;
-
-   /*
-    * Value nodes are inline for performance.  You can treat 'val' as a node,
-    * as in IsA(&val, Integer).  'val' is not valid if isnull is true.
-    */
-   union ValUnion
-   {
-       Node        node;
-       Integer     ival;
-       Float       fval;
-       Boolean     boolval;
-       String      sval;
-       BitString   bsval;
-   }           val;
+   union ValUnion val;
    bool        isnull;         /* SQL NULL constant */
    int         location;       /* token location, or -1 if unknown */
 } A_Const;

diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 44ffc73f1559bacc42272a1bb0afe80079b6e00a..69ba254372dd98ce2aaf7a595653d35e84f7ae18 100644 (file)
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1098,7 +1098,7 @@ struct IndexOptInfo
 
    /*
     * Remaining fields are copied from the index AM's API struct
-    * (IndexAmRoutine)
+    * (IndexAmRoutine).  We don't bother to dump them.
     */
    bool        amcanorderbyop pg_node_attr(read_write_ignore);
    bool        amoptionalkey pg_node_attr(read_write_ignore);
@@ -1111,8 +1111,9 @@ struct IndexOptInfo
    bool        amcanparallel pg_node_attr(read_write_ignore);
    /* does AM have ammarkpos interface? */
    bool        amcanmarkpos pg_node_attr(read_write_ignore);
+   /* AM's cost estimator */
    /* Rather than include amapi.h here, we declare amcostestimate like this */
-   void        (*amcostestimate) ();   /* AM's cost estimator */
+   void        (*amcostestimate) () pg_node_attr(read_write_ignore);
 };
 
 /*