twn_textures.c: support for .so rodata inference

src/game_object/twn_linux_game_object.c

@@ -140,3 +140,10 @@ bool game_object_try_reloading(void) {
 void game_object_tick(void) {
     game_tick_callback();
 }
+
+void *game_object_get_game_tick_address(void) {
+#pragma GCC diagnostic push 
+#pragma GCC diagnostic ignored "-Wpedantic"
+    return (void *)&game_tick_callback;
+#pragma GCC diagnostic pop
+}

src/game_object/twn_static_game_object.c

@@ -19,3 +19,10 @@ bool game_object_try_reloading(void) {
 void game_object_tick(void) {
     game_tick();
 }
+
+void *game_object_get_game_tick_address(void) {
+#pragma GCC diagnostic push 
+#pragma GCC diagnostic ignored "-Wpedantic"
+    return (void *)&game_tick;
+#pragma GCC diagnostic pop
+}

src/system/linux/twn_elf.c

@@ -1,10 +1,13 @@
-#include "elf.h"
+#include "twn_elf.h"
+#include "twn_game_object_c.h"
 
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/auxv.h>
 #include <elf.h>
 #include <linux/limits.h>
+#define __USE_GNU
+#include <dlfcn.h>
 
 #include <stdbool.h>
 #include <stdio.h>
@@ -17,10 +20,21 @@ bool infer_elf_section_bounds(const char *const restrict name,
 {
     bool result = false;
     char buf[PATH_MAX];
-    ssize_t l = readlink("/proc/self/exe", buf, PATH_MAX);
-    if (l == -1)
-        goto ERR_CANT_READLINK;
-    buf[l] = 0; /* readlink() doesn't write a terminator */
+    bool from_shared_object;
+    Dl_info info;
+
+    if (!dladdr(game_object_get_game_tick_address(), &info)) {
+        /* statically linked */
+        from_shared_object = false;
+        ssize_t l = readlink("/proc/self/exe", buf, PATH_MAX);
+        if (l == -1)
+            goto ERR_CANT_READLINK;
+        buf[l] = 0; /* readlink() doesn't write a terminator */
+    } else {
+        /* dynamically linked */
+        from_shared_object = true;
+        memcpy(buf, "libgame.so", sizeof "libgame.so");
+    }
 
     int elf = open(buf, O_RDONLY);
     if (elf == -1)
@@ -51,8 +65,15 @@ bool infer_elf_section_bounds(const char *const restrict name,
 
         if (strcmp(&sh[shdr.sh_name], name) == 0) {
             result = true;
-            *vm_start = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr;
-            *vm_end   = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr + shdr.sh_size;
+
+            if (!from_shared_object) {
+                *vm_start = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr;
+                *vm_end   = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr + shdr.sh_size;
+            } else {
+                *vm_start = (uintptr_t)info.dli_fbase + (char *)shdr.sh_addr;
+                *vm_end   = (uintptr_t)info.dli_fbase + (char *)shdr.sh_addr + shdr.sh_size;
+            }
+
             break;
         }
     }

src/twn_game_object.c

@@ -1,12 +0,0 @@
-#if defined(TWN_FEATURE_DYNLIB_GAME)
-    #if defined(__linux__)
-        #include "game_object/twn_linux_game_object_c.h"
-    #elif defined(_WIN32)
-        #include "game_object/twn_win32_game_object_c.h"
-    #else
-        #warning "TWN_FEATURE_DYNLIB_GAME is set, but not supported"
-        #include "game_object/twn_static_game_object_c.h"
-    #endif
-#else
-    #include "game_object/twn_static_game_object_c.h"
-#endif

src/twn_game_object_c.h

@@ -18,5 +18,6 @@ bool game_object_try_reloading(void);
 
 void game_object_tick(void);
 
+void *game_object_get_game_tick_address(void);
 
 #endif

src/twn_textures.c

@@ -413,7 +413,7 @@ void textures_update_atlas(struct texture_cache *cache) {
 }
 
 /* EXPERIMANTAL: LIKELY TO BE REMOVED! */
-#if defined(__linux__) && !defined(HOT_RELOAD_SUPPORT) /* use rodata elf section for fast lookups of repeating textures */
+#if defined(__linux__) /* use rodata elf section for fast lookups of repeating textures */
 
 #include "system/linux/twn_elf.h"