Add support to uncompressed literal section

Starting from OTP-28 literals are not compressed anymore, so `LITT` will
contain uncompressed data.
OTP PR and issues contain further information about how to distinguish
between compressed and uncompressed sections.

See also:
- erlang/otp#8940
- erlang/otp#8967
- erlang/otp#8988

Signed-off-by: Davide Bettio <davide@uninstall.it>

Author: bettio

src/libAtomVM/module.c

@@ -56,6 +56,7 @@
         return;                                  \
     }
 
+static bool module_are_literals_compressed(const uint8_t *litT);
 #ifdef WITH_ZLIB
     static void *module_uncompress_literals(const uint8_t *litT, int size);
 #endif
@@ -294,20 +295,26 @@ Module *module_new_from_iff_binary(GlobalContext *global, const void *iff_binary
     list_init(&mod->line_ref_offsets);
 
     if (offsets[LITT]) {
-        #ifdef WITH_ZLIB
-            mod->literals_data = module_uncompress_literals(beam_file + offsets[LITT], sizes[LITT]);
-            if (IS_NULL_PTR(mod->literals_data)) {
+        if (!module_are_literals_compressed(beam_file + offsets[LITT])) {
+            mod->literals_data = beam_file + offsets[LITT] + LITT_HEADER_SIZE;
+            mod->free_literals_data = 0;
+
+        } else {
+            #ifdef WITH_ZLIB
+                mod->literals_data = module_uncompress_literals(beam_file + offsets[LITT], sizes[LITT]);
+                if (IS_NULL_PTR(mod->literals_data)) {
+                    module_destroy(mod);
+                    return NULL;
+                }
+                mod->free_literals_data = 1;
+            #else
+                fprintf(stderr, "Error: zlib required to uncompress literals.\n");
                 module_destroy(mod);
                 return NULL;
-            }
-        #else
-            fprintf(stderr, "Error: zlib required to uncompress literals.\n");
-            module_destroy(mod);
-            return NULL;
-        #endif
+            #endif
+        }
 
         mod->literals_table = module_build_literals_table(mod->literals_data);
-        mod->free_literals_data = 1;
 
     } else if (offsets[LITU]) {
         mod->literals_data = beam_file + offsets[LITU] + IFF_SECTION_HEADER_SIZE;
@@ -340,6 +347,12 @@ COLD_FUNC void module_destroy(Module *module)
     free(module);
 }
 
+static bool module_are_literals_compressed(const uint8_t *litT)
+{
+    uint32_t required_buf_size = READ_32_ALIGNED(litT + LITT_UNCOMPRESSED_SIZE_OFFSET);
+    return (required_buf_size != 0);
+}
+
 #ifdef WITH_ZLIB
 static void *module_uncompress_literals(const uint8_t *litT, int size)
 {

tools/packbeam/packbeam.c

@@ -47,6 +47,7 @@ typedef struct FileData {
 } FileData;
 
 static void pad_and_align(FILE *f);
+bool are_literals_compressed(const uint8_t *litT);
 static void *uncompress_literals(const uint8_t *litT, int size, size_t *uncompressedSize);
 static void add_module_header(FILE *f, const char *module_name, uint32_t flags);
 static void pack_beam_file(FILE *pack, const uint8_t *data, size_t size, const char *filename, int is_entrypoint, bool include_lines);
@@ -338,15 +339,21 @@ static void pack_beam_file(FILE *pack, const uint8_t *data, size_t size, const c
         assert_fwrite(data + offsets[LINT], sizes[LINT] + IFF_SECTION_HEADER_SIZE, pack);
         pad_and_align(pack);
     }
-
     if (offsets[LITT]) {
-        size_t u_size;
-        void *deflated = uncompress_literals(data + offsets[LITT], sizes[LITT], &u_size);
-        assert_fwrite("LitU", 4, pack);
-        uint32_t size_field = ENDIAN_SWAP_32(u_size);
-        assert_fwrite(&size_field, sizeof(size_field), pack);
-        assert_fwrite(deflated, u_size, pack);
-        free(deflated);
+        const uint8_t *litt = data + offsets[LITT];
+        size_t litt_size = sizes[LITT];
+        if (are_literals_compressed(litt)) {
+            size_t u_size;
+            void *deflated = uncompress_literals(data + offsets[LITT], litt_size, &u_size);
+            assert_fwrite("LitU", 4, pack);
+            uint32_t size_field = ENDIAN_SWAP_32(u_size);
+            assert_fwrite(&size_field, sizeof(size_field), pack);
+            assert_fwrite(deflated, u_size, pack);
+            free(deflated);
+        } else {
+            assert_fwrite(data + offsets[LITT], sizes[LITT] + IFF_SECTION_HEADER_SIZE, pack);
+            pad_and_align(pack);
+        }
     }
 
     pad_and_align(pack);
@@ -419,6 +426,12 @@ static int do_list(int argc, char **argv)
     return ret;
 }
 
+bool are_literals_compressed(const uint8_t *litT)
+{
+    unsigned int required_buf_size = READ_32_ALIGNED(litT + LITT_UNCOMPRESSED_SIZE_OFFSET);
+    return (required_buf_size != 0);
+}
+
 static void *uncompress_literals(const uint8_t *litT, int size, size_t *uncompressedSize)
 {
     unsigned int required_buf_size = READ_32_ALIGNED(litT + LITT_UNCOMPRESSED_SIZE_OFFSET);