bun:ffi: stop allocating TinyCC JIT memory from the CRT heap on Windows

patches/tinycc/tccrun.c.patch

@@ -0,0 +1,68 @@
+--- tccrun.c
++++ tccrun.c
+@@ -130,8 +130,15 @@
+     //printf("map %p %p %p\n", ptr, prw, (void*)ptr_diff);
+     size *= 2;
+ #else
++# ifdef _WIN32
++    /* Generated code is page-protected below; avoid changing CRT heap pages. */
++    ptr = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
++# else
+     ptr = tcc_malloc(size += PAGESIZE); /* one extra page to align malloc memory */
++# endif
+ #endif
++    if (!ptr)
++        return tcc_error_noabort("tccrun: could not allocate memory");
+     s1->run_ptr = ptr;
+     s1->run_size = size;
+     return ptr_diff;
+@@ -188,12 +195,20 @@
+ #ifdef CONFIG_SELINUX
+     munmap(ptr, size);
+ #else
++# ifdef _WIN32
++    (void)size;
++#  ifdef _WIN64
++    win64_del_function_table(s1->run_function_table);
++#  endif
++    VirtualFree(ptr, 0, MEM_RELEASE);
++# else
+     /* unprotect memory to make it usable for malloc again */
+     protect_pages((void*)PAGEALIGN(ptr), size - PAGESIZE, 2 /*rw*/);
+ # ifdef _WIN64
+     win64_del_function_table(s1->run_function_table);
+ # endif
+     tcc_free(ptr);
++# endif
+ #endif
+ }
+
+@@ -414,7 +429,11 @@
+             }
+             if (protect_pages((void*)addr, n, f) < 0)
+                 return tcc_error_noabort(
++#ifdef _WIN32
++                    "VirtualProtect failed");
++#else
+                     "mprotect failed (did you mean to configure --with-selinux?)");
++#endif
+         }
+     }
+
+@@ -487,11 +506,14 @@
+     void *p = NULL;
+     if (s1->uw_pdata) {
+         p = (void*)s1->uw_pdata->sh_addr;
+-        RtlAddFunctionTable(
++        if (!RtlAddFunctionTable(
+             (RUNTIME_FUNCTION*)p,
+             s1->uw_pdata->data_offset / sizeof (RUNTIME_FUNCTION),
+             s1->pe_imagebase
+-            );
++            )) {
++            tcc_error_noabort("RtlAddFunctionTable failed");
++            p = NULL;
++        }
+         s1->uw_pdata = NULL;
+     }
+     return p;

scripts/build/deps/tinycc.ts

@@ -28,7 +28,13 @@ export const tinycc: Dependency = {
     commit: TINYCC_COMMIT,
   }),
 
-  patches: ["patches/tinycc/tcc.h.patch"],
+  patches: [
+    "patches/tinycc/tcc.h.patch",
+    // Backport of upstream tinycc mob 6728a64f1b (win32: VirtualAlloc for run
+    // memory) and 601a088214 (win32 tccrun diagnostics); the pinned fork
+    // predates both. Drop once TINYCC_COMMIT advances past a merge of those.
+    "patches/tinycc/tccrun.c.patch",
+  ],
 
   build: cfg => {
     const sources = ["libtcc.c", "tccpp.c", "tccgen.c", "tccdbg.c", "tccelf.c", "tccasm.c", "tccrun.c"];