feat: Add 32-bit platform support for graphid type (apache#2286)

* feat: Add 32-bit platform support for graphid type

This enables AGE to work on 32-bit platforms including WebAssembly (WASM).

Problem:
- graphid is int64 (8 bytes) with PASSEDBYVALUE
- On 32-bit systems, Datum is only 4 bytes
- PostgreSQL rejects pass-by-value types larger than Datum

Solution:
- Makefile-only change (no C code modifications)
- When SIZEOF_DATUM=4 is passed to make, strip PASSEDBYVALUE from the generated SQL
- If not specified, normal 64-bit behavior is preserved (PASSEDBYVALUE kept)

This change is backward compatible:
- 64-bit systems continue using pass-by-value
- 32-bit systems now work with pass-by-reference

Motivation: PGlite (PostgreSQL compiled to WebAssembly) uses 32-bit
pointers and requires this patch to run AGE.

Tested on:
- 64-bit Linux (regression tests pass)
- 32-bit WebAssembly via PGlite (all operations work)

Co-authored-by: abbuehlj <[email protected]>

Author: 2 people

Makefile

@@ -138,6 +138,10 @@ PG_CONFIG ?= pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)
 include $(PGXS)
 
+# 32-bit platform support: pass SIZEOF_DATUM=4 to enable (e.g., make SIZEOF_DATUM=4)
+# When SIZEOF_DATUM=4, PASSEDBYVALUE is stripped from graphid type for pass-by-reference.
+# If not specified, normal 64-bit behavior is used (PASSEDBYVALUE preserved).
+
 src/backend/parser/cypher_keywords.o: src/include/parser/cypher_kwlist_d.h
 
 src/include/parser/cypher_kwlist_d.h: src/include/parser/cypher_kwlist.h $(GEN_KEYWORDLIST_DEPS)
@@ -152,8 +156,14 @@ src/backend/parser/cypher_parser.bc: src/backend/parser/cypher_gram.c src/includ
 src/backend/parser/cypher_keywords.o: src/backend/parser/cypher_gram.c src/include/parser/cypher_gram_def.h
 src/backend/parser/cypher_keywords.bc: src/backend/parser/cypher_gram.c src/include/parser/cypher_gram_def.h
 
-$(age_sql):
+# Strip PASSEDBYVALUE on 32-bit (SIZEOF_DATUM=4) for graphid pass-by-reference
+$(age_sql): $(SQLS)
 	@cat $(SQLS) > $@
+ifeq ($(SIZEOF_DATUM),4)
+	@echo "32-bit build: removing PASSEDBYVALUE from graphid type"
+	@sed 's/^  PASSEDBYVALUE,$$/  -- PASSEDBYVALUE removed for 32-bit (see Makefile)/' $@ > [email protected] && mv [email protected] $@
+	@grep -q 'PASSEDBYVALUE removed for 32-bit' $@ || { echo "Error: PASSEDBYVALUE replacement failed in $@"; exit 1; }
+endif
 
 src/backend/parser/ag_scanner.c: FLEX_NO_BACKUP=yes