fix: free table68k + branch_condition_table on shutdown (#125)

The sanitizers CI job (added in PR #121) surfaced two ASAN leaks
totaling ~1.5 MB on every test run after the m68000 UBSAN noise
was filtered out:

  1. table68k (src/m68000/readcpu.c:928) -- 65536 * sizeof(struct
     instr) ~= 1.5 MB.  Allocated lazily on first m68k_pulse_reset,
     never freed.
  2. branch_condition_table (src/tom/gpu.c:257) -- 256 bytes (32 * 8
     conditional-flag LUT).  Allocated by GPUInit ->
     build_branch_condition_table, never freed.

Both are process-lifetime one-time inits.  In a libretro core that
gets dlopen'd / dlclose'd repeatedly (e.g., the iOS Provenance host),
these leaked on every load cycle.

Fix:
  - Add GPUDone() -- frees branch_condition_table, NULLs the pointer
    so a subsequent GPUInit re-allocates cleanly.  Wired into
    TOMDone alongside OPDone() / BlitterDone().
  - Add m68k_done() -- frees table68k, NULLs the pointer, resets the
    file-scope `emulation_initialized` flag (was function-static in
    m68k_pulse_reset; hoisted to file scope so the new done can
    reset it).  Wired into JaguarDone after the existing subsystem
    Done() calls.

Both done functions are idempotent and safe to call without a prior
init (free(NULL) is a no-op).

Closes #125.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

Author: JoeMatt

src/core/jaguar.c

@@ -919,6 +919,7 @@ void JaguarDone(void)
    DSPDone();
    TOMDone();
    JERRYDone();
+   m68k_done();
 }
 
 uint8_t * GetRamPtr(void)

src/m68000/m68kinterface.c

@@ -78,11 +78,25 @@ void M68KDebugResume(void)
 }
 
 
+// File-scope so m68k_done() below can reset it after freeing table68k.
+static uint32_t emulation_initialized = 0;
+
+// Free process-lifetime allocations made by read_table68k().  Called
+// from JaguarDone() so ASAN runs see a clean shutdown.
+extern struct instr * table68k;
+void m68k_done(void)
+{
+	if (table68k)
+	{
+		free(table68k);
+		table68k = NULL;
+	}
+	emulation_initialized = 0;
+}
+
 // Pulse the RESET line on the CPU
 void m68k_pulse_reset(void)
 {
-	static uint32_t emulation_initialized = 0;
-
 	// The first call to this function initializes the opcode handler jump table
 	if (!emulation_initialized)
 	{

src/m68000/m68kinterface.h

@@ -70,6 +70,7 @@ typedef enum
 #define M68K_INT_ACK_SPURIOUS      0xFFFFFFFE
 
 void m68k_pulse_reset(void);
+void m68k_done(void);
 int m68k_execute(int num_cycles);
 void m68k_set_irq(unsigned int int_level);
 

src/tom/gpu.c

@@ -642,6 +642,20 @@ void GPUInit(void)
    GPUReset();
 }
 
+void GPUDone(void)
+{
+   /* Release the branch-condition LUT so process-lifetime ASAN runs
+    * don't report it as a leak.  Safe to call without a matching
+    * GPUInit (free(NULL) is a no-op) and safe to re-call after a
+    * subsequent GPUInit (build_branch_condition_table early-outs on
+    * non-NULL pointer). */
+   if (branch_condition_table)
+   {
+      free(branch_condition_table);
+      branch_condition_table = NULL;
+   }
+}
+
 void GPUReset(void)
 {
    unsigned i;

src/tom/gpu.h

@@ -15,6 +15,7 @@ extern "C" {
 #define GPU_WORK_RAM_BASE		0x00F03000
 
 void GPUInit(void);
+void GPUDone(void);
 void GPUReset(void);
 void GPUExec(int32_t);
 void GPUUpdateRegisterBanks(void);

src/tom/tom.c

@@ -846,6 +846,7 @@ void TOMDone(void)
 {
    OPDone();
    BlitterDone();
+   GPUDone();
 }