Making CallContext and InlineCodeBlock less special-case-y

As committed, gen_node_support.pl excludes CallContext and InlineCodeBlock
from getting unneeded support functions via some very ad-hoc code.
(Right now, there are some other node types that are handled similarly,
but I'm looking to drive that set to empty.)  After looking at the
situation a bit, I think the problem is that these nodes are declared
in parsenodes.h even though they have exactly nothing to do with
parse trees.  What they are is function-calling API infrastructure,
so it seems like the most natural home for them is fmgr.h.  A weaker
case could be made for funcapi.h, perhaps.

So I tried moving them to fmgr.h, and it blew up because they need
typedef NodeTag while fmgr.h does not #include nodes.h.  I feel that
the most reasonable approach is to just give up on that bit of
micro-optimization and let fmgr.h include nodes.h.  It was already
doing a bit of hackery to compile "Node *" references without that
inclusion, so this seems more clean not less so.

Hence, I propose the attached.  (The changes in the PL files are
just to align them on a common best practice for an InlineCodeBlock
argument.)

            regards, tom lane

diff --git a/src/backend/nodes/Makefile b/src/backend/nodes/Makefile
index 79ce0a532f..03c488304e 100644
--- a/src/backend/nodes/Makefile
+++ b/src/backend/nodes/Makefile
@@ -43,6 +43,7 @@ node_headers = \
     nodes/parsenodes.h \
     nodes/replnodes.h \
     nodes/value.h \
+    fmgr.h \
     commands/trigger.h \
     commands/event_trigger.h \
     foreign/fdwapi.h \
diff --git a/src/backend/nodes/gen_node_support.pl b/src/backend/nodes/gen_node_support.pl
index 4a7902e6bf..eef2deb2d8 100644
--- a/src/backend/nodes/gen_node_support.pl
+++ b/src/backend/nodes/gen_node_support.pl
@@ -97,10 +97,8 @@ push @scalar_types, qw(QualCost);

 # XXX various things we are not publishing right now to stay level
 # with the manual system
-push @no_copy,  qw(CallContext InlineCodeBlock);
-push @no_equal, qw(CallContext InlineCodeBlock);
 push @no_read_write,
-  qw(AccessPriv AlterTableCmd CallContext CreateOpClassItem FunctionParameter InferClause InlineCodeBlock
ObjectWithArgsOnConflictClause PartitionCmd RoleSpec VacuumRelation); 
+  qw(AccessPriv AlterTableCmd CreateOpClassItem FunctionParameter InferClause ObjectWithArgs OnConflictClause
PartitionCmdRoleSpec VacuumRelation); 
 push @no_read, qw(A_ArrayExpr A_Indices A_Indirection AlterStatsStmt
   CollateClause ColumnDef ColumnRef CreateForeignTableStmt CreateStatsStmt
   CreateStmt FuncCall ImportForeignSchemaStmt IndexElem IndexStmt
@@ -298,7 +296,7 @@ foreach my $infile (@ARGV)
                     # Nodes from these files don't need support functions,
                     # just node tags.
                     if (elem basename($infile),
-                        qw(execnodes.h trigger.h event_trigger.h amapi.h tableam.h
+                        qw(execnodes.h fmgr.h trigger.h event_trigger.h amapi.h tableam.h
                         tsmapi.h fdwapi.h tuptable.h replnodes.h supportnodes.h)
                       )
                     {
diff --git a/src/include/fmgr.h b/src/include/fmgr.h
index 5314b73705..dfbf24897e 100644
--- a/src/include/fmgr.h
+++ b/src/include/fmgr.h
@@ -18,8 +18,9 @@
 #ifndef FMGR_H
 #define FMGR_H

-/* We don't want to include primnodes.h here, so make some stub references */
-typedef struct Node *fmNodePtr;
+#include "nodes/nodes.h"
+
+/* We don't want to include primnodes.h here, so make a stub reference */
 typedef struct Aggref *fmAggrefPtr;

 /* Likewise, avoid including execnodes.h here */
@@ -63,7 +64,7 @@ typedef struct FmgrInfo
     unsigned char fn_stats;        /* collect stats if track_functions > this */
     void       *fn_extra;        /* extra space for use by handler */
     MemoryContext fn_mcxt;        /* memory context to store fn_extra in */
-    fmNodePtr    fn_expr;        /* expression parse tree for call, or NULL */
+    Node       *fn_expr;        /* expression parse tree for call, or NULL */
 } FmgrInfo;

 /*
@@ -85,8 +86,8 @@ typedef struct FmgrInfo
 typedef struct FunctionCallInfoBaseData
 {
     FmgrInfo   *flinfo;            /* ptr to lookup info used for this call */
-    fmNodePtr    context;        /* pass info about context of call */
-    fmNodePtr    resultinfo;        /* pass or return extra info about result */
+    Node       *context;        /* pass info about context of call */
+    Node       *resultinfo;        /* pass or return extra info about result */
     Oid            fncollation;    /* collation for function to use */
 #define FIELDNO_FUNCTIONCALLINFODATA_ISNULL 4
     bool        isnull;            /* function must set true if result is NULL */
@@ -708,9 +709,9 @@ extern const Pg_finfo_record *fetch_finfo_record(void *filehandle, const char *f
 extern Oid    fmgr_internal_function(const char *proname);
 extern Oid    get_fn_expr_rettype(FmgrInfo *flinfo);
 extern Oid    get_fn_expr_argtype(FmgrInfo *flinfo, int argnum);
-extern Oid    get_call_expr_argtype(fmNodePtr expr, int argnum);
+extern Oid    get_call_expr_argtype(Node *expr, int argnum);
 extern bool get_fn_expr_arg_stable(FmgrInfo *flinfo, int argnum);
-extern bool get_call_expr_arg_stable(fmNodePtr expr, int argnum);
+extern bool get_call_expr_arg_stable(Node *expr, int argnum);
 extern bool get_fn_expr_variadic(FmgrInfo *flinfo);
 extern bytea *get_fn_opclass_options(FmgrInfo *flinfo);
 extern bool has_fn_opclass_options(FmgrInfo *flinfo);
@@ -751,6 +752,37 @@ extern void AggRegisterCallback(FunctionCallInfo fcinfo,
                                 fmExprContextCallbackFunction func,
                                 Datum arg);

+/*
+ * Support for DO blocks
+ *
+ * If a procedural language supports DO, it will provide a "laninline"
+ * handler function.  DO invokes that function passing an InlineCodeBlock
+ * node as the single argument.
+ */
+typedef struct InlineCodeBlock
+{
+    NodeTag        type;
+    char       *source_text;    /* source text of anonymous code block */
+    Oid            langOid;        /* OID of selected language */
+    bool        langIsTrusted;    /* trusted property of the language */
+    bool        atomic;            /* atomic execution context? */
+} InlineCodeBlock;
+
+/*
+ * Support for procedures
+ *
+ * Procedures are called using the same low-level mechanism as functions,
+ * but the fcinfo->context field is a CallContext node.  This lets the
+ * callee know that it is being called via CALL rather than function
+ * syntax, and provides information about whether the semantic context
+ * is atomic or non-atomic.
+ */
+typedef struct CallContext
+{
+    NodeTag        type;
+    bool        atomic;            /* atomic execution context? */
+} CallContext;
+
 /*
  * We allow plugin modules to hook function entry/exit.  This is intended
  * as support for loadable security policy modules, which may want to
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 0b6a7bb365..8011224d22 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -3370,8 +3370,6 @@ typedef struct AlterFunctionStmt

 /* ----------------------
  *        DO Statement
- *
- * DoStmt is the raw parser output, InlineCodeBlock is the execution-time API
  * ----------------------
  */
 typedef struct DoStmt
@@ -3380,15 +3378,6 @@ typedef struct DoStmt
     List       *args;            /* List of DefElem nodes */
 } DoStmt;

-typedef struct InlineCodeBlock
-{
-    NodeTag        type;
-    char       *source_text;    /* source text of anonymous code block */
-    Oid            langOid;        /* OID of selected language */
-    bool        langIsTrusted;    /* trusted property of the language */
-    bool        atomic;            /* atomic execution context */
-} InlineCodeBlock;
-
 /* ----------------------
  *        CALL statement
  *
@@ -3406,12 +3395,6 @@ typedef struct CallStmt
     List       *outargs;        /* transformed output-argument expressions */
 } CallStmt;

-typedef struct CallContext
-{
-    NodeTag        type;
-    bool        atomic;
-} CallContext;
-
 /* ----------------------
  *        Alter Object Rename Statement
  * ----------------------
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index edb93ec1c4..62c74a6da0 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -1881,7 +1881,7 @@ Datum
 plperl_inline_handler(PG_FUNCTION_ARGS)
 {
     LOCAL_FCINFO(fake_fcinfo, 0);
-    InlineCodeBlock *codeblock = (InlineCodeBlock *) PG_GETARG_POINTER(0);
+    InlineCodeBlock *codeblock = castNode(InlineCodeBlock, PG_GETARG_POINTER(0));
     FmgrInfo    flinfo;
     plperl_proc_desc desc;
     plperl_call_data *volatile save_call_data = current_call_data;
diff --git a/src/pl/plpgsql/src/pl_handler.c b/src/pl/plpgsql/src/pl_handler.c
index 190d286f1c..cee393e4e0 100644
--- a/src/pl/plpgsql/src/pl_handler.c
+++ b/src/pl/plpgsql/src/pl_handler.c
@@ -315,7 +315,7 @@ Datum
 plpgsql_inline_handler(PG_FUNCTION_ARGS)
 {
     LOCAL_FCINFO(fake_fcinfo, 0);
-    InlineCodeBlock *codeblock = castNode(InlineCodeBlock, DatumGetPointer(PG_GETARG_DATUM(0)));
+    InlineCodeBlock *codeblock = castNode(InlineCodeBlock, PG_GETARG_POINTER(0));
     PLpgSQL_function *func;
     FmgrInfo    flinfo;
     EState       *simple_eval_estate;
diff --git a/src/pl/plpython/plpy_main.c b/src/pl/plpython/plpy_main.c
index 0bce106495..a7012c6c5b 100644
--- a/src/pl/plpython/plpy_main.c
+++ b/src/pl/plpython/plpy_main.c
@@ -265,7 +265,7 @@ Datum
 plpython3_inline_handler(PG_FUNCTION_ARGS)
 {
     LOCAL_FCINFO(fake_fcinfo, 0);
-    InlineCodeBlock *codeblock = (InlineCodeBlock *) DatumGetPointer(PG_GETARG_DATUM(0));
+    InlineCodeBlock *codeblock = castNode(InlineCodeBlock, PG_GETARG_POINTER(0));
     FmgrInfo    flinfo;
     PLyProcedure proc;
     PLyExecutionContext *exec_ctx;
diff --git a/src/tools/msvc/Solution.pm b/src/tools/msvc/Solution.pm
index b8b1728df7..80d90294ba 100644
--- a/src/tools/msvc/Solution.pm
+++ b/src/tools/msvc/Solution.pm
@@ -855,6 +855,7 @@ EOF
           nodes/parsenodes.h
           nodes/replnodes.h
           nodes/value.h
+          fmgr.h
           commands/trigger.h
           commands/event_trigger.h
           foreign/fdwapi.h