From ab71d7532fad832fc74548ba05c28890f6481603 Mon Sep 17 00:00:00 2001
From: Dipin Hora <dipinhora+github@gmail.com>
Date: Thu, 5 Dec 2024 09:28:57 -0500
Subject: [PATCH 1/5] Deterministic cerealisation for cross binary
 communication

Prior to this commit, serialisation used the `type_id` of the
types that it serialised and the `type_id`s assigned to types
can vary depending on the program being compiled. This makes it
impossible for cross binary serialisation even if the same pony
version and types are used.

This commit changes things so that serialisation now uses a
determnistically assigned `serialise_id` instead of the `type_id`.
This new `serialise_id` is guaranteed to be the same for the same
pony version and type (see details for caveats).

The changes include:

* adding a `size_t` size `serialise_id` to `pony_type_t`
* hashes the reach_type_t->name to generate either a 63 bit or
  31 bit `serialise_id` depending on target platform
* the hash for the `serialise_id` uses a `key` that is based on the
  blake2 encoding of the pony version, the target data model, and
  the endianness (i.e. `pony-0.58.7-ac1c51b69-lp64-le`). This is
  to ensure that only programs with the same `key` will have the
  same `serialise_id` to prevent silent data corruption during
  deserialisation due to subtle differences in platforms. This
  means that cross binary serialisation will only work for binaries
  of the same bit width (32 bit vs 64 bit), data model (ilp32, lp64,
  or llp64), and endianness (big endian or little endian)
* serialisation now uses the `serialise_id` instead of the `type_id`
* deserialisation now uses the `serialise_id` to look up the
  `type_id` to get the entry in the descriptor table instead of
  looking up the entry in the descriptor table directly based on
  `type_id`
---
 src/libponyc/ast/ast.c              |  3 +
 src/libponyc/ast/source.c           |  1 +
 src/libponyc/ast/stringtab.c        |  2 +
 src/libponyc/ast/symtab.c           |  1 +
 src/libponyc/ast/token.c            |  3 +
 src/libponyc/codegen/codegen.c      | 26 ++++++++
 src/libponyc/codegen/codegen.h      |  3 +
 src/libponyc/codegen/gendesc.c      | 92 +++++++++++++++++++++++------
 src/libponyc/codegen/gendesc.h      |  2 +
 src/libponyc/codegen/genexe.c       | 10 +++-
 src/libponyc/codegen/genname.c      |  7 +++
 src/libponyc/codegen/genname.h      |  2 +
 src/libponyc/codegen/genprim.c      |  8 +--
 src/libponyc/codegen/genserialise.c | 35 +++++------
 src/libponyc/codegen/genserialise.h |  4 +-
 src/libponyc/codegen/gentype.c      |  1 +
 src/libponyc/pass/pass.h            |  1 +
 src/libponyc/pkg/package.c          |  6 ++
 src/libponyc/pkg/program.c          |  1 +
 src/libponyc/reach/reach.c          | 33 +++++++++++
 src/libponyc/reach/reach.h          |  1 +
 src/libponyc/type/reify.c           |  1 +
 src/libponyrt/ds/fun.c              | 13 +++-
 src/libponyrt/ds/fun.h              |  4 ++
 src/libponyrt/ds/hash.h             |  1 +
 src/libponyrt/ds/list.h             |  1 +
 src/libponyrt/gc/cycle.c            |  1 +
 src/libponyrt/gc/serialise.c        | 29 +++++++--
 src/libponyrt/gc/serialise.h        |  3 +-
 src/libponyrt/pony.h                | 10 ++++
 src/libponyrt/sched/start.c         |  3 +-
 test/libponyrt/ds/hash.cc           |  1 +
 32 files changed, 255 insertions(+), 54 deletions(-)

diff --git a/src/libponyc/ast/ast.c b/src/libponyc/ast/ast.c
index d0774aea49..31d13660d5 100644
--- a/src/libponyc/ast/ast.c
+++ b/src/libponyc/ast/ast.c
@@ -2013,6 +2013,7 @@ static pony_type_t ast_signature_pony =
   sizeof(ast_signature_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   ast_signature_serialise_trace,
@@ -2092,6 +2093,7 @@ static pony_type_t ast_nominal_pkg_id_signature_pony =
   sizeof(ast_signature_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   ast_nominal_pkg_id_signature_serialise_trace,
@@ -2355,6 +2357,7 @@ static pony_type_t ast_pony =
   sizeof(ast_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   ast_serialise_trace,
diff --git a/src/libponyc/ast/source.c b/src/libponyc/ast/source.c
index 1e01cff87e..be0cbd926f 100644
--- a/src/libponyc/ast/source.c
+++ b/src/libponyc/ast/source.c
@@ -114,6 +114,7 @@ static pony_type_t source_pony =
   sizeof(source_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   source_serialise_trace,
diff --git a/src/libponyc/ast/stringtab.c b/src/libponyc/ast/stringtab.c
index 9a83b8efde..7b1ded094c 100644
--- a/src/libponyc/ast/stringtab.c
+++ b/src/libponyc/ast/stringtab.c
@@ -134,6 +134,7 @@ static __pony_thread_local struct _pony_type_t string_pony =
   0,
   0,
   0,
+  0,
   NULL,
   NULL,
   NULL,
@@ -220,6 +221,7 @@ static pony_type_t strlist_pony =
   sizeof(strlist_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   strlist_serialise_trace,
diff --git a/src/libponyc/ast/symtab.c b/src/libponyc/ast/symtab.c
index 09b9e67b99..b972254e4f 100644
--- a/src/libponyc/ast/symtab.c
+++ b/src/libponyc/ast/symtab.c
@@ -389,6 +389,7 @@ static pony_type_t symbol_pony =
   sizeof(symbol_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   symbol_serialise_trace,
diff --git a/src/libponyc/ast/token.c b/src/libponyc/ast/token.c
index 14ebb96be0..fb876e9492 100644
--- a/src/libponyc/ast/token.c
+++ b/src/libponyc/ast/token.c
@@ -404,6 +404,7 @@ static pony_type_t token_signature_pony =
   sizeof(token_signature_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   token_signature_serialise_trace,
@@ -458,6 +459,7 @@ static pony_type_t token_docstring_signature_pony =
   sizeof(token_signature_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   token_docstring_signature_serialise_trace,
@@ -546,6 +548,7 @@ static pony_type_t token_pony =
   sizeof(token_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   token_serialise_trace,
diff --git a/src/libponyc/codegen/codegen.c b/src/libponyc/codegen/codegen.c
index a4536e70f7..a0727e13a3 100644
--- a/src/libponyc/codegen/codegen.c
+++ b/src/libponyc/codegen/codegen.c
@@ -15,6 +15,7 @@
 #include "../../libponyrt/mem/pool.h"
 #include "ponyassert.h"
 
+#include <blake2.h>
 #include <platform.h>
 #include <llvm-c/DebugInfo.h>
 #include <llvm-c/Initialization.h>
@@ -202,6 +203,13 @@ static void init_runtime(compile_t* c)
   c->msg_type = LLVMStructCreateNamed(c->context, "__message");
   LLVMStructSetBody(c->msg_type, params, 2, false);
 
+  // descriptor_offset_lookup
+  // uint32_t (*)(size_t)
+  params[0] = target_is_ilp32(c->opt->triple) ? c->i32 : c->i64;
+  c->descriptor_offset_lookup_type = LLVMFunctionType(c->i32, params, 1, false);
+  c->descriptor_offset_lookup_fn =
+    LLVMPointerType(c->descriptor_offset_lookup_type, 0);
+
   // trace
   // void (*)(i8*, __object*)
   params[0] = c->ptr;
@@ -856,6 +864,21 @@ bool codegen_pass_init(pass_opt_t* opt)
   else
     opt->cpu = LLVMGetHostCPUName();
 
+  opt->serialise_id_hash_key = (unsigned char*)ponyint_pool_alloc_size(16);
+
+  const char* version = "pony-" PONY_VERSION;
+  const char* data_model = target_is_ilp32(opt->triple) ? "ilp32" : (target_is_lp64(opt->triple) ? "lp64" : (target_is_llp64(opt->triple) ? "llp64" : "unknown"));
+  const char* endian = target_is_bigendian(opt->triple) ? "be" : "le";
+
+  printbuf_t* target_version_buf = printbuf_new();
+  printbuf(target_version_buf, "%s-%s-%s", version, data_model, endian);
+
+  int status = blake2b(opt->serialise_id_hash_key, 16, target_version_buf->m, target_version_buf->offset, NULL, 0);
+  (void)status;
+  pony_assert(status == 0);
+
+  printbuf_free(target_version_buf);
+
   return true;
 }
 
@@ -872,6 +895,9 @@ void codegen_pass_cleanup(pass_opt_t* opt)
   opt->triple = NULL;
   opt->cpu = NULL;
   opt->features = NULL;
+
+  ponyint_pool_free_size(16, opt->serialise_id_hash_key);
+  opt->serialise_id_hash_key = NULL;
 }
 
 bool codegen(ast_t* program, pass_opt_t* opt)
diff --git a/src/libponyc/codegen/codegen.h b/src/libponyc/codegen/codegen.h
index 822ea3982b..c95d943f05 100644
--- a/src/libponyc/codegen/codegen.h
+++ b/src/libponyc/codegen/codegen.h
@@ -172,6 +172,7 @@ typedef struct compile_t
   LLVMValueRef primitives_init;
   LLVMValueRef primitives_final;
   LLVMValueRef desc_table;
+  LLVMValueRef desc_table_offset_lookup_fn;
   LLVMValueRef numeric_sizes;
 
   LLVMTypeRef void_type;
@@ -187,6 +188,8 @@ typedef struct compile_t
 
   LLVMTypeRef ptr;
   LLVMTypeRef descriptor_type;
+  LLVMTypeRef descriptor_offset_lookup_type;
+  LLVMTypeRef descriptor_offset_lookup_fn;
   LLVMTypeRef field_descriptor;
   LLVMTypeRef object_type;
   LLVMTypeRef msg_type;
diff --git a/src/libponyc/codegen/gendesc.c b/src/libponyc/codegen/gendesc.c
index b1444d2a4b..f9455f4c52 100644
--- a/src/libponyc/codegen/gendesc.c
+++ b/src/libponyc/codegen/gendesc.c
@@ -12,24 +12,25 @@
 
 #define DESC_ID 0
 #define DESC_SIZE 1
-#define DESC_FIELD_COUNT 2
-#define DESC_FIELD_OFFSET 3
-#define DESC_INSTANCE 4
-#define DESC_TRACE 5
-#define DESC_SERIALISE_TRACE 6
-#define DESC_SERIALISE 7
-#define DESC_DESERIALISE 8
-#define DESC_CUSTOM_SERIALISE_SPACE 9
-#define DESC_CUSTOM_DESERIALISE 10
-#define DESC_DISPATCH 11
-#define DESC_FINALISE 12
-#define DESC_EVENT_NOTIFY 13
-#define DESC_MIGHT_REFERENCE_ACTOR 14
-#define DESC_TRAITS 15
-#define DESC_FIELDS 16
-#define DESC_VTABLE 17
-
-#define DESC_LENGTH 18
+#define DESC_SERIALISEID 2
+#define DESC_FIELD_COUNT 3
+#define DESC_FIELD_OFFSET 4
+#define DESC_INSTANCE 5
+#define DESC_TRACE 6
+#define DESC_SERIALISE_TRACE 7
+#define DESC_SERIALISE 8
+#define DESC_DESERIALISE 9
+#define DESC_CUSTOM_SERIALISE_SPACE 10
+#define DESC_CUSTOM_DESERIALISE 11
+#define DESC_DISPATCH 12
+#define DESC_FINALISE 13
+#define DESC_EVENT_NOTIFY 14
+#define DESC_MIGHT_REFERENCE_ACTOR 15
+#define DESC_TRAITS 16
+#define DESC_FIELDS 17
+#define DESC_VTABLE 18
+
+#define DESC_LENGTH 19
 
 static LLVMValueRef make_unbox_function(compile_t* c, reach_type_t* t,
   reach_method_t* m)
@@ -330,6 +331,7 @@ void gendesc_basetype(compile_t* c, LLVMTypeRef desc_type)
 
   params[DESC_ID] = c->i32;
   params[DESC_SIZE] = c->i32;
+  params[DESC_SERIALISEID] = target_is_ilp32(c->opt->triple) ? c->i32 : c->i64;
   params[DESC_FIELD_COUNT] = c->i32;
   params[DESC_FIELD_OFFSET] = c->i32;
   params[DESC_INSTANCE] = c->ptr;
@@ -377,6 +379,7 @@ void gendesc_type(compile_t* c, reach_type_t* t)
 
   params[DESC_ID] = c->i32;
   params[DESC_SIZE] = c->i32;
+  params[DESC_SERIALISEID] = target_is_ilp32(c->opt->triple) ? c->i32 : c->i64;
   params[DESC_FIELD_COUNT] = c->i32;
   params[DESC_FIELD_OFFSET] = c->i32;
   params[DESC_INSTANCE] = c->ptr;
@@ -414,6 +417,7 @@ void gendesc_init(compile_t* c, reach_type_t* t)
   LLVMValueRef args[DESC_LENGTH];
   args[DESC_ID] = LLVMConstInt(c->i32, t->type_id, false);
   args[DESC_SIZE] = LLVMConstInt(c->i32, c_t->abi_size, false);
+  args[DESC_SERIALISEID] = LLVMConstInt(target_is_ilp32(c->opt->triple) ? c->i32 : c->i64, t->serialise_id, false);
   args[DESC_FIELD_COUNT] = make_field_count(c, t);
   args[DESC_FIELD_OFFSET] = make_field_offset(c, t);
   args[DESC_INSTANCE] = make_desc_ptr(c, c_t->instance);
@@ -478,6 +482,58 @@ void gendesc_table(compile_t* c)
   ponyint_pool_free_size(size, args);
 }
 
+void gendesc_table_lookup(compile_t* c)
+{
+  reach_type_t* t;
+  size_t i = HASHMAP_BEGIN;
+
+  LLVMValueRef desc_lkp_fn = codegen_addfun(c, "__DescOffsetLookupFn",
+    c->descriptor_offset_lookup_type, false);
+  codegen_startfun(c, desc_lkp_fn, NULL, NULL, NULL, false);
+  LLVMSetFunctionCallConv(desc_lkp_fn, LLVMCCallConv);
+  LLVMSetLinkage(desc_lkp_fn, LLVMExternalLinkage);
+
+  LLVMBasicBlockRef unreachable = codegen_block(c, "unreachable");
+
+  // Read the serialise ID.
+  LLVMValueRef serialise_id = LLVMGetParam(desc_lkp_fn, 0);
+
+  // switch based on serialise_id
+  LLVMValueRef serialise_switch = LLVMBuildSwitch(c->builder, serialise_id, unreachable, 0);
+
+  // the default case is unreachable unless something major has gone wrong
+  LLVMPositionBuilderAtEnd(c->builder, unreachable);
+
+  LLVMValueRef ret = LLVMConstInt(c->i32, (uint32_t)-1, false);
+  LLVMBuildRet(c->builder, ret);
+
+  while((t = reach_types_next(&c->reach->types, &i)) != NULL)
+  {
+    if(t->is_trait || (t->underlying == TK_STRUCT))
+      continue;
+
+    pony_assert(t->serialise_id != (uint64_t)-1);
+
+    LLVMBasicBlockRef type_block = codegen_block(c,
+      genname_type_with_id(t->name, t->serialise_id));
+
+    LLVMAddCase(serialise_switch, LLVMConstInt(target_is_ilp32(c->opt->triple) ? c->i32 : c->i64, t->serialise_id, false),
+      type_block);
+
+    LLVMPositionBuilderAtEnd(c->builder, type_block);
+
+    ret = LLVMConstInt(c->i32, t->type_id, false);
+    LLVMBuildRet(c->builder, ret);
+  }
+
+  // Mark the default case as unreachable.
+  LLVMPositionBuilderAtEnd(c->builder, unreachable);
+
+  codegen_finishfun(c);
+
+  c->desc_table_offset_lookup_fn = make_desc_ptr(c, desc_lkp_fn);
+}
+
 static LLVMValueRef desc_field(compile_t* c, LLVMValueRef desc, int index)
 {
   LLVMTypeRef field_type = LLVMStructGetTypeAtIndex(c->descriptor_type, index);
diff --git a/src/libponyc/codegen/gendesc.h b/src/libponyc/codegen/gendesc.h
index 97c76aea27..cd8f7a90a7 100644
--- a/src/libponyc/codegen/gendesc.h
+++ b/src/libponyc/codegen/gendesc.h
@@ -14,6 +14,8 @@ void gendesc_init(compile_t* c, reach_type_t* t);
 
 void gendesc_table(compile_t* c);
 
+void gendesc_table_lookup(compile_t* c);
+
 LLVMValueRef gendesc_fetch(compile_t* c, LLVMValueRef object);
 
 LLVMValueRef gendesc_typeid(compile_t* c, LLVMValueRef desc);
diff --git a/src/libponyc/codegen/genexe.c b/src/libponyc/codegen/genexe.c
index 9ae3ff1679..832c83969a 100644
--- a/src/libponyc/codegen/genexe.c
+++ b/src/libponyc/codegen/genexe.c
@@ -52,14 +52,16 @@ static LLVMValueRef make_lang_features_init(compile_t* c)
     boolean = c->i8;
 
   uint32_t desc_table_size = reach_max_type_id(c->reach);
+  LLVMValueRef desc_table_lookup_fn = c->desc_table_offset_lookup_fn;
 
-  LLVMTypeRef f_params[4];
+  LLVMTypeRef f_params[5];
   f_params[0] = boolean;
   f_params[1] = boolean;
   f_params[2] = c->ptr;
   f_params[3] = c->intptr;
+  f_params[4] = c->descriptor_offset_lookup_fn;
 
-  LLVMTypeRef lfi_type = LLVMStructTypeInContext(c->context, f_params, 4,
+  LLVMTypeRef lfi_type = LLVMStructTypeInContext(c->context, f_params, 5,
     false);
 
   LLVMBasicBlockRef this_block = LLVMGetInsertBlock(c->builder);
@@ -89,6 +91,10 @@ static LLVMValueRef make_lang_features_init(compile_t* c)
   LLVMBuildStore(c->builder, LLVMConstInt(c->intptr, desc_table_size, false),
     field);
 
+  field = LLVMBuildStructGEP2(c->builder, lfi_type, lfi_object, 4, "");
+  LLVMBuildStore(c->builder, LLVMBuildBitCast(c->builder, desc_table_lookup_fn,
+    c->descriptor_offset_lookup_fn, ""), field);
+
   return lfi_object;
 }
 
diff --git a/src/libponyc/codegen/genname.c b/src/libponyc/codegen/genname.c
index a481f31dca..cab07cf70a 100644
--- a/src/libponyc/codegen/genname.c
+++ b/src/libponyc/codegen/genname.c
@@ -199,3 +199,10 @@ const char* genname_program_fn(const char* program, const char* name)
 {
   return stringtab_two(program, name);
 }
+
+const char* genname_type_with_id(const char* type, uint64_t type_id)
+{
+  printbuf_t* buf = printbuf_new();
+  printbuf(buf, "%s_%" PRIu64, type, type_id);
+  return stringtab_buf(buf);
+}
diff --git a/src/libponyc/codegen/genname.h b/src/libponyc/codegen/genname.h
index 13d39ee334..ce160524b0 100644
--- a/src/libponyc/codegen/genname.h
+++ b/src/libponyc/codegen/genname.h
@@ -42,6 +42,8 @@ const char* genname_unsafe(const char* name);
 
 const char* genname_program_fn(const char* program, const char* name);
 
+const char* genname_type_with_id(const char* type, uint64_t type_id);
+
 PONY_EXTERN_C_END
 
 #endif
diff --git a/src/libponyc/codegen/genprim.c b/src/libponyc/codegen/genprim.c
index d5fb517ec2..4da0b2b73b 100644
--- a/src/libponyc/codegen/genprim.c
+++ b/src/libponyc/codegen/genprim.c
@@ -776,7 +776,7 @@ void genprim_array_serialise(compile_t* c, reach_type_t* t)
   LLVMValueRef offset_addr = LLVMBuildInBoundsGEP2(c->builder, c->i8, addr,
     &offset, 1, "");
 
-  genserialise_typeid(c, t, offset_addr);
+  genserialise_serialiseid(c, t, offset_addr);
 
   // Don't serialise our contents if we are opaque.
   LLVMBasicBlockRef body_block = codegen_block(c, "body");
@@ -890,7 +890,7 @@ void genprim_array_deserialise(compile_t* c, reach_type_t* t)
 
   LLVMValueRef ctx = LLVMGetParam(c_t->deserialise_fn, 0);
   LLVMValueRef object = LLVMGetParam(c_t->deserialise_fn, 1);
-  gendeserialise_typeid(c, c_t, object);
+  gendeserialise_serialiseid(c, c_t, object);
 
   // Deserialise the array contents.
   LLVMValueRef alloc = field_value(c, c_t->structure, object, 2);
@@ -1010,7 +1010,7 @@ void genprim_string_serialise(compile_t* c, reach_type_t* t)
   LLVMValueRef offset_addr = LLVMBuildInBoundsGEP2(c->builder, c->i8, addr,
     &offset, 1, "");
 
-  genserialise_typeid(c, t, offset_addr);
+  genserialise_serialiseid(c, t, offset_addr);
 
   // Don't serialise our contents if we are opaque.
   LLVMBasicBlockRef body_block = codegen_block(c, "body");
@@ -1069,7 +1069,7 @@ void genprim_string_deserialise(compile_t* c, reach_type_t* t)
   LLVMValueRef ctx = LLVMGetParam(c_t->deserialise_fn, 0);
   LLVMValueRef object = LLVMGetParam(c_t->deserialise_fn, 1);
 
-  gendeserialise_typeid(c, c_t, object);
+  gendeserialise_serialiseid(c, c_t, object);
 
   // Deserialise the string contents.
   LLVMValueRef alloc = field_value(c, c_t->structure, object, 2);
diff --git a/src/libponyc/codegen/genserialise.c b/src/libponyc/codegen/genserialise.c
index e641dcd67a..f2abaf5f66 100644
--- a/src/libponyc/codegen/genserialise.c
+++ b/src/libponyc/codegen/genserialise.c
@@ -3,6 +3,7 @@
 #include "gendesc.h"
 #include "genfun.h"
 #include "genname.h"
+#include "genopt.h"
 #include "genprim.h"
 #include "ponyassert.h"
 #include "../../libponyrt/mem/pool.h"
@@ -19,7 +20,7 @@ static void serialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
   {
     case TK_PRIMITIVE:
     {
-      genserialise_typeid(c, t, offset);
+      genserialise_serialiseid(c, t, offset);
 
       if(c_t->primitive != NULL)
       {
@@ -37,7 +38,7 @@ static void serialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
 
     case TK_CLASS:
     {
-      genserialise_typeid(c, t, offset);
+      genserialise_serialiseid(c, t, offset);
       extra++;
       break;
     }
@@ -45,7 +46,7 @@ static void serialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
     case TK_ACTOR:
     {
       // Skip the actor pad.
-      genserialise_typeid(c, t, offset);
+      genserialise_serialiseid(c, t, offset);
       extra += 2;
       break;
     }
@@ -54,7 +55,7 @@ static void serialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
     {
       if(!is_bare_tuple)
       {
-        genserialise_typeid(c, t, offset);
+        genserialise_serialiseid(c, t, offset);
         object = LLVMBuildStructGEP2(c->builder, c_t->structure, object, 1, "");
         LLVMValueRef size = LLVMConstInt(c->intptr,
           LLVMOffsetOfElement(c->target_data, structure, 1), false);
@@ -103,10 +104,10 @@ static void serialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
   }
 }
 
-void genserialise_typeid(compile_t* c, reach_type_t* t, LLVMValueRef offset)
+void genserialise_serialiseid(compile_t* c, reach_type_t* t, LLVMValueRef offset)
 {
-  // Write the type id instead of the descriptor.
-  LLVMValueRef value = LLVMConstInt(c->intptr, t->type_id, false);
+  // Write the serialise id instead of the descriptor.
+  LLVMValueRef value = LLVMConstInt(target_is_ilp32(c->opt->triple) ? c->i32 : c->i64, t->serialise_id, false);
   LLVMBuildStore(c->builder, value, offset);
 }
 
@@ -136,7 +137,7 @@ static void serialise_bare_interface(compile_t* c, reach_type_t* t,
     LLVMValueRef test = LLVMBuildICmp(c->builder, LLVMIntEQ, obj,
       ((compile_type_t*)sub->c_type)->instance, "");
     LLVMBuildCondBr(c->builder, test, post_block, next_block);
-    LLVMValueRef value = LLVMConstInt(c->intptr, sub->type_id, false);
+    LLVMValueRef value = LLVMConstInt(target_is_ilp32(c->opt->triple) ? c->i32 : c->i64, sub->serialise_id, false);
     LLVMAddIncoming(phi, &value, &current_block, 1);
     LLVMPositionBuilderAtEnd(c->builder, next_block);
     sub = next;
@@ -145,7 +146,7 @@ static void serialise_bare_interface(compile_t* c, reach_type_t* t,
   }
 
   LLVMBuildBr(c->builder, post_block);
-  LLVMValueRef value = LLVMConstInt(c->intptr, sub->type_id, false);
+  LLVMValueRef value = LLVMConstInt(target_is_ilp32(c->opt->triple) ? c->i32 : c->i64, sub->serialise_id, false);
   LLVMAddIncoming(phi, &value, &current_block, 1);
 
   LLVMMoveBasicBlockAfter(post_block, current_block);
@@ -168,12 +169,12 @@ void genserialise_element(compile_t* c, reach_type_t* t, bool embed,
     LLVMValueRef value = LLVMBuildLoad2(c->builder, c_t->mem_type, ptr, "");
     LLVMBuildStore(c->builder, value, offset);
   } else if(t->bare_method != NULL) {
-    // Bare object, either write the type id directly if it is a concrete object
-    // or compute the type id based on the object value and write it if it isn't.
+    // Bare object, either write the serialise_id id directly if it is a concrete object
+    // or compute the serialise_id id based on the object value and write it if it isn't.
     switch(t->underlying)
     {
       case TK_PRIMITIVE:
-        genserialise_typeid(c, t, offset);
+        genserialise_serialiseid(c, t, offset);
         break;
 
       case TK_INTERFACE:
@@ -237,7 +238,7 @@ static void deserialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
     case TK_PRIMITIVE:
     case TK_CLASS:
     {
-      gendeserialise_typeid(c, c_t, object);
+      gendeserialise_serialiseid(c, c_t, object);
       extra++;
       break;
     }
@@ -245,7 +246,7 @@ static void deserialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
     case TK_ACTOR:
     {
       // Skip the actor pad.
-      gendeserialise_typeid(c, c_t, object);
+      gendeserialise_serialiseid(c, c_t, object);
       extra += 2;
       break;
     }
@@ -254,7 +255,7 @@ static void deserialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
     {
       if(!is_bare_tuple)
       {
-        gendeserialise_typeid(c, c_t, object);
+        gendeserialise_serialiseid(c, c_t, object);
         object = LLVMBuildStructGEP2(c->builder, c_t->structure, object, 1, "");
       }
 
@@ -274,9 +275,9 @@ static void deserialise(compile_t* c, reach_type_t* t, LLVMValueRef ctx,
   }
 }
 
-void gendeserialise_typeid(compile_t* c, compile_type_t* t, LLVMValueRef object)
+void gendeserialise_serialiseid(compile_t* c, compile_type_t* t, LLVMValueRef object)
 {
-  // Write the descriptor instead of the type id.
+  // Write the descriptor instead of the serialiseid id.
   LLVMValueRef desc_ptr = LLVMBuildStructGEP2(c->builder, t->structure, object,
     0, "");
   LLVMBuildStore(c->builder, t->desc, desc_ptr);
diff --git a/src/libponyc/codegen/genserialise.h b/src/libponyc/codegen/genserialise.h
index 45743be46e..92d4d9803f 100644
--- a/src/libponyc/codegen/genserialise.h
+++ b/src/libponyc/codegen/genserialise.h
@@ -11,9 +11,9 @@ typedef struct compile_type_t compile_type_t;
 void genserialise_element(compile_t* c, reach_type_t* t, bool embed,
   LLVMValueRef ctx, LLVMValueRef ptr, LLVMValueRef offset);
 
-void genserialise_typeid(compile_t* c, reach_type_t* t, LLVMValueRef offset);
+void genserialise_serialiseid(compile_t* c, reach_type_t* t, LLVMValueRef offset);
 
-void gendeserialise_typeid(compile_t* c, compile_type_t* t, LLVMValueRef offset);
+void gendeserialise_serialiseid(compile_t* c, compile_type_t* t, LLVMValueRef offset);
 
 void gendeserialise_element(compile_t* c, reach_type_t* t, bool embed,
   LLVMValueRef ctx, LLVMValueRef ptr);
diff --git a/src/libponyc/codegen/gentype.c b/src/libponyc/codegen/gentype.c
index 049947c0aa..6c93bb7947 100644
--- a/src/libponyc/codegen/gentype.c
+++ b/src/libponyc/codegen/gentype.c
@@ -744,6 +744,7 @@ bool gentypes(compile_t* c)
   }
 
   gendesc_table(c);
+  gendesc_table_lookup(c);
 
   c->numeric_sizes = gen_numeric_size_table(c);
 
diff --git a/src/libponyc/pass/pass.h b/src/libponyc/pass/pass.h
index c3356dcab6..5a52ced437 100644
--- a/src/libponyc/pass/pass.h
+++ b/src/libponyc/pass/pass.h
@@ -313,6 +313,7 @@ typedef struct pass_opt_t
   char* abi;
   char* cpu;
   char* features;
+  unsigned char* serialise_id_hash_key;
 
   typecheck_t check;
 
diff --git a/src/libponyc/pkg/package.c b/src/libponyc/pkg/package.c
index 531f707987..2ee105ac05 100644
--- a/src/libponyc/pkg/package.c
+++ b/src/libponyc/pkg/package.c
@@ -1430,6 +1430,7 @@ static pony_type_t package_dep_signature_pony =
   sizeof(package_signature_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   package_dep_signature_serialise_trace,
@@ -1459,6 +1460,7 @@ static pony_type_t package_signature_pony =
   sizeof(package_signature_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   package_signature_serialise_trace,
@@ -1537,6 +1539,7 @@ static pony_type_t package_group_dep_signature_pony =
   sizeof(const char*),
   0,
   0,
+  0,
   NULL,
   NULL,
   package_group_dep_signature_serialise_trace,
@@ -1566,6 +1569,7 @@ static pony_type_t package_group_signature_pony =
   sizeof(const char*),
   0,
   0,
+  0,
   NULL,
   NULL,
   package_group_signature_serialise_trace,
@@ -1715,6 +1719,7 @@ static pony_type_t package_pony =
   sizeof(package_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   package_serialise_trace,
@@ -1788,6 +1793,7 @@ static pony_type_t package_group_pony =
   sizeof(package_group_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   package_group_serialise_trace,
diff --git a/src/libponyc/pkg/program.c b/src/libponyc/pkg/program.c
index a27095a91b..fb60c2979b 100644
--- a/src/libponyc/pkg/program.c
+++ b/src/libponyc/pkg/program.c
@@ -425,6 +425,7 @@ static pony_type_t program_pony =
   sizeof(program_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   program_serialise_trace,
diff --git a/src/libponyc/reach/reach.c b/src/libponyc/reach/reach.c
index ea2e77ae7d..8e3760595f 100644
--- a/src/libponyc/reach/reach.c
+++ b/src/libponyc/reach/reach.c
@@ -2,6 +2,7 @@
 #include "subtype.h"
 #include "../ast/astbuild.h"
 #include "../codegen/genname.h"
+#include "../codegen/genopt.h"
 #include "../pass/expr.h"
 #include "../type/assemble.h"
 #include "../type/cap.h"
@@ -740,6 +741,7 @@ static reach_type_t* add_reach_type(reach_t* r, ast_t* type)
   t->ast = set_cap_and_ephemeral(type, TK_REF, TK_NONE);
   t->ast_cap = ast_dup(type);
   t->type_id = (uint32_t)-1;
+  t->serialise_id = (uint64_t)-1;
 
   ast_set_scope(t->ast, NULL);
   ast_set_scope(t->ast_cap, NULL);
@@ -794,6 +796,15 @@ static reach_type_t* add_tuple(reach_t* r, ast_t* type, pass_opt_t* opt)
   t->type_id = get_new_tuple_id(r);
   t->can_be_boxed = true;
 
+  // TODO: ideally should be hashing AST tree for type name, fields and their types/names
+  // Only use 63/31 bits of the hash because we need the high bit for primitive types
+  if(target_is_ilp32(opt->triple))
+    t->serialise_id = (ponyint_hash_str_custom_key32(opt->serialise_id_hash_key, t->name) >> 1);
+  else
+    t->serialise_id = (ponyint_hash_str_custom_key64(opt->serialise_id_hash_key, t->name) >> 1);
+
+  pony_assert(t->serialise_id != ((uint64_t)-1)); // -1 is for `Pointer`s
+
   t->field_count = (uint32_t)ast_childcount(t->ast);
   t->fields = (reach_field_t*)ponyint_pool_alloc_size(
       t->field_count * sizeof(reach_field_t));
@@ -926,6 +937,15 @@ static reach_type_t* add_nominal(reach_t* r, ast_t* type, pass_opt_t* opt)
       t->type_id = get_new_object_id(r);
   }
 
+  // TODO: ideally should be hashing AST tree for type name, fields and their types/names
+  // Only use 63/31 bits of the hash because we need the high bit for primitive types
+  if(target_is_ilp32(opt->triple))
+    t->serialise_id = (ponyint_hash_str_custom_key32(opt->serialise_id_hash_key, t->name) >> 1);
+  else
+    t->serialise_id = (ponyint_hash_str_custom_key64(opt->serialise_id_hash_key, t->name) >> 1);
+
+  pony_assert(t->serialise_id != ((uint64_t)-1)); // -1 is for `Pointer`s
+
   if(ast_id(def) != TK_PRIMITIVE)
     return t;
 
@@ -1510,6 +1530,10 @@ void reach_dump(reach_t* r)
     size_t j = HASHMAP_BEGIN;
     reach_method_name_t* n;
 
+    printf("    serialise_id: %" PRIu64 "\n", t->serialise_id);
+    printf("    is_trait: %s\n", (t->is_trait)?"true":"false");
+    printf("    can_be_boxed: %s\n", (t->can_be_boxed)?"true":"false");
+
     printf("    vtable: %d\n", t->vtable_size);
 
     while((n = reach_method_names_next(&t->methods, &j)) != NULL)
@@ -1529,6 +1553,8 @@ void reach_dump(reach_t* r)
       printf("    %s\n", t2->name);
     }
   }
+
+  printf("  Total Type Count: %d\n", r->total_type_count);
 }
 
 static void reach_param_serialise_trace(pony_ctx_t* ctx, void* object)
@@ -1571,6 +1597,7 @@ static pony_type_t reach_param_pony =
   sizeof(reach_param_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   reach_param_serialise_trace,
@@ -1706,6 +1733,7 @@ static pony_type_t reach_method_pony =
   sizeof(reach_method_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   reach_method_serialise_trace,
@@ -1769,6 +1797,7 @@ static pony_type_t reach_method_name_pony =
   sizeof(reach_method_name_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   reach_method_name_serialise_trace,
@@ -1827,6 +1856,7 @@ static pony_type_t reach_field_pony =
   sizeof(reach_field_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   reach_field_serialise_trace,
@@ -1898,6 +1928,7 @@ static void reach_type_serialise(pony_ctx_t* ctx, void* object, void* buf,
   dst->vtable_size = t->vtable_size;
   dst->can_be_boxed = t->can_be_boxed;
   dst->is_trait = t->is_trait;
+  dst->serialise_id = t->serialise_id;
 
   dst->field_count = t->field_count;
   dst->fields = (reach_field_t*)pony_serialise_offset(ctx, t->fields);
@@ -1951,6 +1982,7 @@ static pony_type_t reach_type_pony =
   sizeof(reach_type_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   reach_type_serialise_trace,
@@ -2010,6 +2042,7 @@ static pony_type_t reach_pony =
   sizeof(reach_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   reach_serialise_trace,
diff --git a/src/libponyc/reach/reach.h b/src/libponyc/reach/reach.h
index afd0f79025..eee7f81e25 100644
--- a/src/libponyc/reach/reach.h
+++ b/src/libponyc/reach/reach.h
@@ -99,6 +99,7 @@ struct reach_type_t
   reach_type_cache_t subtypes;
   uint32_t type_id;
   uint32_t vtable_size;
+  uint64_t serialise_id;
   bool can_be_boxed;
   bool is_trait;
 
diff --git a/src/libponyc/type/reify.c b/src/libponyc/type/reify.c
index 5ad7e185d1..7a2586d3bd 100644
--- a/src/libponyc/type/reify.c
+++ b/src/libponyc/type/reify.c
@@ -561,6 +561,7 @@ static pony_type_t deferred_reification_pony =
   sizeof(deferred_reification_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   deferred_reification_serialise_trace,
diff --git a/src/libponyrt/ds/fun.c b/src/libponyrt/ds/fun.c
index a9c14d14ec..d0c36d55b7 100644
--- a/src/libponyrt/ds/fun.c
+++ b/src/libponyrt/ds/fun.c
@@ -9,8 +9,6 @@ static const unsigned char the_key[16] = {
 };
 
 
-#ifdef PLATFORM_IS_ILP32
-
 #define ROTL32(x, b) (uint32_t)(((x) << (b)) | ((x) >> (32 - (b))))
 
 #define SIPROUND32 \
@@ -76,7 +74,6 @@ static uint32_t halfsiphash24(const unsigned char* key, const unsigned char* in,
 
   return v0 ^ v1 ^ v2 ^ v3;
 }
-#endif
 
 #define ROTL64(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
 
@@ -149,6 +146,16 @@ PONY_API uint64_t ponyint_hash_block64(const void* p, size_t len)
   return siphash24(the_key, (const unsigned char*)p, len);
 }
 
+uint32_t ponyint_hash_str_custom_key32(const unsigned char* key, const char* str)
+{
+  return halfsiphash24((const unsigned char *)key, (const unsigned char *)str, strlen(str));
+}
+
+uint64_t ponyint_hash_str_custom_key64(const unsigned char* key, const char* str)
+{
+  return siphash24((const unsigned char *)key, (const unsigned char *)str, strlen(str));
+}
+
 size_t ponyint_hash_str(const char* str)
 {
 #ifdef PLATFORM_IS_ILP32
diff --git a/src/libponyrt/ds/fun.h b/src/libponyrt/ds/fun.h
index b19976bc0d..d8310e837c 100644
--- a/src/libponyrt/ds/fun.h
+++ b/src/libponyrt/ds/fun.h
@@ -25,6 +25,10 @@ PONY_API size_t ponyint_hash_block(const void* p, size_t len);
 
 PONY_API uint64_t ponyint_hash_block64(const void* p, size_t len);
 
+uint32_t ponyint_hash_str_custom_key32(const unsigned char* key, const char* str);
+
+uint64_t ponyint_hash_str_custom_key64(const unsigned char* key, const char* str);
+
 size_t ponyint_hash_str(const char* str);
 
 size_t ponyint_hash_ptr(const void* p);
diff --git a/src/libponyrt/ds/hash.h b/src/libponyrt/ds/hash.h
index 39f07138f5..7f08c17336 100644
--- a/src/libponyrt/ds/hash.h
+++ b/src/libponyrt/ds/hash.h
@@ -251,6 +251,7 @@ void ponyint_hashmap_deserialise(pony_ctx_t* ctx, void* object,
     sizeof(name_t), \
     0, \
     0, \
+    0, \
     NULL, \
     NULL, \
     name##_serialise_trace, \
diff --git a/src/libponyrt/ds/list.h b/src/libponyrt/ds/list.h
index 089927e4b2..4a829c691d 100644
--- a/src/libponyrt/ds/list.h
+++ b/src/libponyrt/ds/list.h
@@ -167,6 +167,7 @@ void ponyint_list_deserialise(pony_ctx_t* ctx, void* object,
     sizeof(name_t), \
     0, \
     0, \
+    0, \
     NULL, \
     NULL, \
     name##_serialise_trace, \
diff --git a/src/libponyrt/gc/cycle.c b/src/libponyrt/gc/cycle.c
index 349f08b1d0..6cac328459 100644
--- a/src/libponyrt/gc/cycle.c
+++ b/src/libponyrt/gc/cycle.c
@@ -1225,6 +1225,7 @@ static pony_type_t cycle_type =
   sizeof(detector_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   NULL,
diff --git a/src/libponyrt/gc/serialise.c b/src/libponyrt/gc/serialise.c
index 624e1309e3..6d4b22cb5c 100644
--- a/src/libponyrt/gc/serialise.c
+++ b/src/libponyrt/gc/serialise.c
@@ -20,6 +20,7 @@ PONY_EXTERN_C_BEGIN
 
 static size_t desc_table_size = 0;
 static pony_type_t** desc_table = NULL;
+static desc_offset_lookup_fn desc_table_offset_lookup_fn = NULL;
 
 PONY_EXTERN_C_END
 
@@ -81,22 +82,38 @@ static void custom_deserialise(pony_ctx_t* ctx)
   }
 }
 
-bool ponyint_serialise_setup(pony_type_t** table, size_t table_size)
+bool ponyint_serialise_setup(pony_type_t** table, size_t table_size,
+  desc_offset_lookup_fn desc_table_offset_lookup)
 {
 #ifndef PONY_NDEBUG
   for(uint32_t i = 0; i < table_size; i++)
   {
     if(table[i] != NULL)
+    {
       pony_assert(table[i]->id == i);
+      pony_assert(desc_table_offset_lookup(table[i]->serialise_id) == i);
+    }
   }
 #endif
 
   desc_table = table;
   desc_table_size = table_size;
+  desc_table_offset_lookup_fn = desc_table_offset_lookup;
 
   return true;
 }
 
+static pony_type_t* get_descriptor(size_t serialise_id)
+{
+  uint32_t offset = desc_table_offset_lookup_fn(serialise_id);
+
+  // fail even in release builds because this is unrecoverable
+  if(offset >= desc_table_size || offset < 0)
+    ponyint_assert_fail("deserialise offset invalid", __FILE__, __LINE__, __func__);
+
+  return desc_table[offset];
+}
+
 void ponyint_serialise_object(pony_ctx_t* ctx, void* p, pony_type_t* t,
   int mutability)
 {
@@ -194,7 +211,7 @@ PONY_API size_t pony_serialise_offset(pony_ctx_t* ctx, void* p)
   // If we are not in the map, we are an untraced primitive. Return the type id
   // with the high bit set.
   pony_type_t* t = *(pony_type_t**)p;
-  return (size_t)t->id | HIGH_BIT;
+  return (size_t)t->serialise_id | HIGH_BIT;
 }
 
 PONY_API void pony_serialise(pony_ctx_t* ctx, void* p, pony_type_t* t,
@@ -253,7 +270,7 @@ PONY_API void* pony_deserialise_offset(pony_ctx_t* ctx, pony_type_t* t,
     // Return the global instance, if there is one. It's ok to return null if
     // there is no global instance, as this will then be an unserialised
     // field in an opaque object.
-    t = desc_table[offset];
+    t = get_descriptor(offset);
     return t->instance;
   }
 
@@ -277,9 +294,9 @@ PONY_API void* pony_deserialise_offset(pony_ctx_t* ctx, pony_type_t* t,
       abort();
     }
 
-    // Turn the type id into a descriptor pointer.
-    uintptr_t id = *(uintptr_t*)((uintptr_t)ctx->serialise_buffer + offset);
-    t = desc_table[id];
+    // Turn the serialise id into a descriptor pointer.
+    size_t id = *(uintptr_t*)((uintptr_t)ctx->serialise_buffer + offset);
+    t = get_descriptor(id);
   }
 
   // If it's a primitive, return the global instance.
diff --git a/src/libponyrt/gc/serialise.h b/src/libponyrt/gc/serialise.h
index 4a41da9af9..d31b30ad88 100644
--- a/src/libponyrt/gc/serialise.h
+++ b/src/libponyrt/gc/serialise.h
@@ -23,7 +23,8 @@ typedef struct serialise_t serialise_t;
 
 DECLARE_HASHMAP(ponyint_serialise, ponyint_serialise_t, serialise_t);
 
-bool ponyint_serialise_setup(pony_type_t** table, size_t table_size);
+bool ponyint_serialise_setup(pony_type_t** table, size_t table_size,
+  desc_offset_lookup_fn desc_table_offset_lookup);
 
 void ponyint_serialise_object(pony_ctx_t* ctx, void* p, pony_type_t* t,
   int mutability);
diff --git a/src/libponyrt/pony.h b/src/libponyrt/pony.h
index eed07d3a2e..9aaf8a0a76 100644
--- a/src/libponyrt/pony.h
+++ b/src/libponyrt/pony.h
@@ -134,6 +134,7 @@ typedef const struct _pony_type_t
 {
   uint32_t id;
   uint32_t size;
+  size_t serialise_id;
   uint32_t field_count;
   uint32_t field_offset;
   void* instance;
@@ -152,6 +153,12 @@ typedef const struct _pony_type_t
   void* vtable;
 } pony_type_t;
 
+/** Desc table lookup function.
+ *
+ * A function to convert `serialise_id`s to offsets in the desc table
+ */
+typedef uint32_t (*desc_offset_lookup_fn)(size_t serialise_id);
+
 /** Language feature initialiser.
  *
  * Contains initialisers for the various language features initialised by
@@ -178,6 +185,9 @@ typedef struct pony_language_features_init_t
 
   /// The total size of the descriptor_table array.
   size_t descriptor_table_size;
+
+  /// The function to translate `serialise_id`s to offsets in the desc_table
+  desc_offset_lookup_fn desc_table_offset_lookup;
 } pony_language_features_init_t;
 
 /// The currently executing context.
diff --git a/src/libponyrt/sched/start.c b/src/libponyrt/sched/start.c
index a7acca53fa..71d3621316 100644
--- a/src/libponyrt/sched/start.c
+++ b/src/libponyrt/sched/start.c
@@ -334,7 +334,8 @@ PONY_API bool pony_start(bool library, int* exit_code,
 
     if(language_init.init_serialisation &&
       !ponyint_serialise_setup(language_init.descriptor_table,
-        language_init.descriptor_table_size))
+        language_init.descriptor_table_size,
+        language_init.desc_table_offset_lookup))
     {
       atomic_store_explicit(&running, NOT_RUNNING, memory_order_relaxed);
       return false;
diff --git a/test/libponyrt/ds/hash.cc b/test/libponyrt/ds/hash.cc
index 4a4ea1f1c2..663dfe42c0 100644
--- a/test/libponyrt/ds/hash.cc
+++ b/test/libponyrt/ds/hash.cc
@@ -72,6 +72,7 @@ static pony_type_t hash_elem_pony =
   sizeof(hash_elem_t),
   0,
   0,
+  0,
   NULL,
   NULL,
   hash_elem_serialise_trace,

From 162a6732a162bf44aa798600fc041f41cb9e0774 Mon Sep 17 00:00:00 2001
From: Dipin Hora <dipinhora+github@gmail.com>
Date: Thu, 5 Dec 2024 10:58:28 -0500
Subject: [PATCH 2/5] remove always false if condition

---
 src/libponyrt/gc/serialise.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libponyrt/gc/serialise.c b/src/libponyrt/gc/serialise.c
index 6d4b22cb5c..75fbdb4aef 100644
--- a/src/libponyrt/gc/serialise.c
+++ b/src/libponyrt/gc/serialise.c
@@ -108,7 +108,7 @@ static pony_type_t* get_descriptor(size_t serialise_id)
   uint32_t offset = desc_table_offset_lookup_fn(serialise_id);
 
   // fail even in release builds because this is unrecoverable
-  if(offset >= desc_table_size || offset < 0)
+  if(offset >= desc_table_size)
     ponyint_assert_fail("deserialise offset invalid", __FILE__, __LINE__, __func__);
 
   return desc_table[offset];

From 1a80c4e811280bbf3133ddb8257740f70ba31010 Mon Sep 17 00:00:00 2001
From: Dipin Hora <dipinhora+github@gmail.com>
Date: Thu, 5 Dec 2024 11:48:56 -0500
Subject: [PATCH 3/5] add release notes

---
 .release-notes/4567.md | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 .release-notes/4567.md

diff --git a/.release-notes/4567.md b/.release-notes/4567.md
new file mode 100644
index 0000000000..da14f858e4
--- /dev/null
+++ b/.release-notes/4567.md
@@ -0,0 +1,3 @@
+## Deterministic cerealisation for cross binary communication
+
+Pony built-in serialisation can now be used between binaries compiled with the same version of the pony compiler (this would likely result in segfaults previously). Cross binary serialisation will only work for binaries of the same bit width (32 bit vs 64 bit), data model (ilp32, lp64, or llp64), and endianness (big endian or little endian) but is not limited to a single platform (for example: one can mix and match x86_64 linux and aarch64 linux because they have the same bitwidth, data model, and endianness).

From e4a197d25acfd210753451522ee2b6fe60a9aca7 Mon Sep 17 00:00:00 2001
From: Sean T Allen <sean@seantallen.com>
Date: Thu, 5 Dec 2024 14:16:40 -0500
Subject: [PATCH 4/5] Update .release-notes/4567.md

---
 .release-notes/4567.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.release-notes/4567.md b/.release-notes/4567.md
index da14f858e4..77d6b3ae7b 100644
--- a/.release-notes/4567.md
+++ b/.release-notes/4567.md
@@ -1,3 +1,3 @@
-## Deterministic cerealisation for cross binary communication
+## Deterministic serialisation for cross binary communication
 
 Pony built-in serialisation can now be used between binaries compiled with the same version of the pony compiler (this would likely result in segfaults previously). Cross binary serialisation will only work for binaries of the same bit width (32 bit vs 64 bit), data model (ilp32, lp64, or llp64), and endianness (big endian or little endian) but is not limited to a single platform (for example: one can mix and match x86_64 linux and aarch64 linux because they have the same bitwidth, data model, and endianness).

From c357dcd19313e11b74374ead1d2f972e9c0e0840 Mon Sep 17 00:00:00 2001
From: Dipin Hora <dipinhora+github@gmail.com>
Date: Thu, 19 Dec 2024 19:14:43 -0500
Subject: [PATCH 5/5] Update serialise package docs and remove release notes

---
 .release-notes/4567.md            |  3 ---
 packages/serialise/serialise.pony | 16 +++++++++-------
 2 files changed, 9 insertions(+), 10 deletions(-)
 delete mode 100644 .release-notes/4567.md

diff --git a/.release-notes/4567.md b/.release-notes/4567.md
deleted file mode 100644
index 77d6b3ae7b..0000000000
--- a/.release-notes/4567.md
+++ /dev/null
@@ -1,3 +0,0 @@
-## Deterministic serialisation for cross binary communication
-
-Pony built-in serialisation can now be used between binaries compiled with the same version of the pony compiler (this would likely result in segfaults previously). Cross binary serialisation will only work for binaries of the same bit width (32 bit vs 64 bit), data model (ilp32, lp64, or llp64), and endianness (big endian or little endian) but is not limited to a single platform (for example: one can mix and match x86_64 linux and aarch64 linux because they have the same bitwidth, data model, and endianness).
diff --git a/packages/serialise/serialise.pony b/packages/serialise/serialise.pony
index 66e71fc535..d169ba7ce8 100644
--- a/packages/serialise/serialise.pony
+++ b/packages/serialise/serialise.pony
@@ -15,16 +15,18 @@ invariants. However, if only "trusted" data (i.e. data produced by Pony
 serialisation from the same binary) is deserialised, it will always maintain a
 well-formed heap and all object invariants.
 
-Note that serialised data is not usable between different Pony binaries. This is
-due to the use of type identifiers rather than a heavy-weight self-describing
-serialisation schema. This also means it isn't safe to deserialise something
-serialised by the same program compiled for a different platform.
+Note that serialised data can be used between binaries compiled with the same
+version of the pony compiler. Cross binary serialisation will only work for
+binaries of the same bit width (32 bit vs 64 bit), data model (ilp32, lp64, or
+llp64), and endianness (big endian or little endian) but is not limited to a
+single platform (for example: one can mix and match x86_64 linux and aarch64
+linux because they have the same bitwidth, data model, and endianness).
 
 The [Serialise.signature](serialise-Serialise.md#signature) method is provided
 for the purposes of comparing communicating Pony binaries to determine if they
-are the same. Confirming this before deserialising data can help mitigate the
-risk of accidental serialisation across different Pony binaries, but does not on
-its own address the security issues of accepting data from untrusted sources.
+are compatible. Confirming this before deserialising data can help mitigate the
+risk of accidental serialisation across incompatible Pony binaries, but does not
+on its own address the security issues of accepting data from untrusted sources.
 """
 
 use @"internal.signature"[Array[U8] val]()